SRF2013 - List of Keywords (vacuum)

Paper	Title	Other Keywords	Page
MOIOA02	Status and Challenges of Spiral2 SRF Linac	cryomodule, linac, cavity, ion	11
	R. Ferdinand, P.-E. Bernaudin, M. Di Giacomo GANIL, Caen, France P. Bosland CEA/IRFU, Gif-sur-Yvette, France Y. Gómez Martínez LPSC, Grenoble Cedex, France G. Olry IPN, Orsay, France
	GANIL is presently extending its experimental facility with the new SPIRAL2 project. It is based on a multi-beam Superconducting Linac Driver delivering 5 mA deuterons up to 40 MeV and 1 mA heavy ions up to 14.5 MeV/u. Several domains of research in nuclear physics at the limits of stability will be covered by this new accelerator. SPIRAL2 construction has two phases. SPIRAL2 phase 1 includes the superconducting accelerator driver, and the construction of the two research areas where the accelerated protons and deuterons will generate extremely intense neutron beams for fundamental physics experiments and numerous applications. SPIRAL2 will also accelerate stable heavy ion beams of very high intensity. The phase2 includes the RIB production building and links to the existing GANIL accelerator complex for RIB post acceleration. The Superconducting Linac incorporates many innovative developments of the Quarter-Wave resonators and their associated cryogenic and RF systems. The installation of the SPIRAL2 accelerator at GANIL has started. Status of the Spiral 2 SRF linac will be presented, focusing on the various SRF challenges met by this project and how/what solutions were chosen. * on behalf of the SPIRAL2 project and superconducting teams
	Slides MOIOA02 [87.841 MB]

MOP009	A Summary of the Advanced Photon Source (APS) Short Pulse X-ray (SPX) R&D Accomplishments	cavity, cryomodule, LLRF, laser	92
	A. Nassiri, N.D. Arnold, T.G. Berenc, M. Borland, B. Brajuskovic, D.J. Bromberek, J. Carwardine, G. Decker, L. Emery, J.D. Fuerst, J.P. Holzbauer, D. Horan, J.A. Kaluzny, J.S. Kerby, F. Lenkszus, R.M. Lill, H. Ma, V. Sajaev, B.K. Stillwell, G.J. Waldschmidt, M. White, G. Wu, Y. Yang, A. Zholents ANL, Argonne, USA J.M. Byrd, L.R. Doolittle, G. Huang LBNL, Berkeley, California, USA P. Dhakal, J. Henry, J.D. Mammosser, J. Matalevich, R.A. Rimmer, H. Wang, K.M. Wilson JLAB, Newport News, Virginia, USA Z. Li, L. Xiao SLAC, Menlo Park, California, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06H11357. The Advanced Photon Source Upgrade Project (APS-U) at Argonne will include generation of short-pulse x-rays based on Zholents’ [1] deflecting cavity scheme. We have chosen superconducting (SC) cavities in order to have a continuous train of crabbed bunches and flexibility of operating modes. Since early 2012, in collaboration with Jefferson National Laboratory, we have made significant progress prototyping and testing a number of single-cell deflecting cavities. We have designed, prototyped, and tested silicon carbide as damping material for higher-order-mode (HOM) dampers, which are broadband to handle the HOM power across the frequency spectrum produced by the APS beam. In collaboration with Lawrence Berkeley National Laboratory, we have developing a state-of-the-art timing and synchronization system for distributing stable rf signals over optical fiber capable of achieving tens of femtoseconds phase drift and jitter. Collaboration with the Advanced Computations Department at Stanford Linear Accelerator Center is looking into simulations of complex, multi- cavity geometries. This contribution provides a progress report on the current R&D status of the SPX project. [1] A. Zholents et al., NIM A 425, 385 (1999).

MOP014	Cold Tests of SSR1 Resonators for PXIE	cavity, radiation, cryomodule, SRF	112
	A.I. Sukhanov, M.H. Awida, P. Berrutti, C.M. Ginsburg, T.N. Khabiboulline, O.S. Melnychuk, R.V. Pilipenko, Y.M. Pischalnikov, L. Ristori, A.M. Rowe, D.A. Sergatskov, V.P. Yakovlev Fermilab, Batavia, USA
	Fermilab is currently building the Project X Injector experiment (PXIE). PXIE linac will accelerate 1 mA H⁻ beam up to 30 MeV and serve as a testbed for validation of Project X concepts and mitigation of technical risks. A cryomodule of eight superconducting RF Single Spoke Resonators of type 1 (SSR1) cavities operating at 325 MHz is an integral part of PXIE. Ten SSR1 cavities were manufactured in industry and delivered to Fermilab. In this paper we discuss surface processing and tests of bare SSR1 cavities at the Fermilab Vertical Test Stand (VTS). We report on the measured performance parameters of nine cavities achieved during tests.

MOP030	Post-Production Dimensional Control of the Cold Masses and Vacuum Vessels for the XFEL Cryomodules	controls, alignment, cryomodule, site	165
	S. Barbanotti, W. Benecke, K. Jensch, M. Noak, M. Schlösser DESY, Hamburg, Germany
	The very tight alignment tolerances required in the XFEL Linac reflect in very tight tolerances for the production of the main cryomodule components. To verify the adherence to the specified tolerances of the cold masses and vacuum vessels, dimensional controls with laser tracker are performed at the production site following DESY experts’ instructions and verified at DESY with an independent measurement. We present here the measurement strategy and a summary of the results obtained so far.

MOP031	Quality Control of the Vessel and Cold Mass Production for the 1.3 GHz XFEL Cryomodules	controls, cryomodule, operation, cavity	168
	S. Barbanotti, H. Hintz, K. Jensch, W. Maschmann DESY, Hamburg, Germany
	The industrial production of one hundred cold masses and vacuum vessels for the 1.3 GHz XFEL cryomodules is now fully in operation. Quality checks at the companies and controls at DESY assure the quality level required for the cryomodule assembly. Verification of the main production steps, non-destructive tests, dimensional controls are performed by DESY personnel before accepting the components. This paper resumes the quality control strategy and the results for the first components produced by the companies.

MOP036	New Technique and Result of Laser Welded SCRF Cavity Developed at RRCAT	cavity, laser, niobium, experiment	186
	P. Khare, R. Arya, J. Dwivedi, R. Ghosh, G. Gilankar, C. Gupta, P.D. Gupta, A. Jain, S.C. Joshi, G.V. Kane, R. Kaul, P.K. Kush, G. Mundra, S.M. Oak, C.K. Pithawa, P. Ram Sankar, S.B. Roy, V.C. Sahni, R.S. Sandha, P. Shrivastava, B.N. Upadhyay RRCAT, Indore (M.P.), India C.A. Cooper, C.M. Ginsburg, A. Grassellino, C.S. Mishra, A.M. Rowe Fermilab, Batavia, USA
	A new technique to fabricate SCRF cavities with the help of laser welding process has been developed at Raja Ramanna Centre for Advanced Technology RRCAT), Indore, Department of Atomic Energy, India. In this technique, a pulsed Nd:YAG laser has been used and welding was performed in inert gas environment, in a specially designed welding rig. The advantages of this technique are reduced cost, small heat affected zone, no necessity to weld in vacuum and enhanced rate of production. The paper describes the technique and fabrication method of a single-cell 1.3 GHz SCRF cavity which was fabricated at RRCAT with this new technique. It also discusses the test result of this cavity which was processed and tested at Fermilab. The cavity reached an Eacc of 17MV/m with a Q0 of 1.4 E +10 at 2K. The cavity is being barrel polished for further improvement.

MOP037	Test of the 1.3 GHz Superconducting Cavities for the European X-ray Free Electron Laser	cavity, HOM, software, pick-up	191
	K. Krzysik DESY, Hamburg, Germany B. Dzieza, W. Gaj, D. Karolczyk, K. Kasprzak, L.M. Kolwicz-Chodak, A. Kotarba, A. Krawczyk, W. Maciocha, A. Marendziak, K. Myalski, S. Myalski, T. Ostrowicz, B. Prochal, M. Sienkiewicz, M. Skiba, J. Świerbleski, M. Wiencek, J. Zbroja, A. Zwozniak IFJ-PAN, Kraków, Poland
	The European X-ray Free Electron Laser (XFEL) is currently under construction in Germany in Hamburg area. A linear accelerating part of the XFEL is going to consist of 808 superconducting 9-cell Niobium cavities installed in 101 accelerating modules. Before assembly into modules the cavities are tested in a dedicated test facilities. The testing procedures are prepared based on DESY expertise and available software from Tesla Test Facility (TTF) Collaboration and Free electron LASer for Hamburg (FLASH). RF test provides the most important information about cavity performance: maximum available gradient and dependence of quality factor and radiation on the gradient. Results of the RF test determine, whether a cavity is shipped to CEA Saclay (France) to be assembled into a module or send for retreatment to improve its performance. In this paper we present the most important aspects of the cavity RF test procedure.

MOP040	Industrialization of European XFEL Preparation Cycle “Final EP ” at Research Instruments Company	cavity, controls, acceleration, radiation	201
	A. Matheisen, N. Krupka, M. Schalwat, A. Schmidt, M. Schmökel, W. Singer, B. van der Horst DESY, Hamburg, Germany P. Michelato, L. Monaco INFN/LASA, Segrate (MI), Italy M. Pekeler RI Research Instruments GmbH, Bergisch Gladbach, Germany
	In the Specification for XFEL Cavity preparation (R1) two different preparation sequences are presented. Research Instruments Company as one of the two companies contracted for XFEL cavity production and preparation has chosen the so called “final EP” cycle. Major infrastructure components like EP facility and the BCP facility were pre- qualified. This existing and the new set up areas like the cleanroom are distributed over the ground area of the industrial park Bergisch Gladbach. The process flow given in the DESY specification needed adaptation to this scenario. Additional infrastructure beside the once specified needed to be set up to ensure the same quality of processes even with a changed work flow. The general lay out of the facility, matched work flow of preparation and test results of resonators processed by RI company in their infrastructure will be reported. (R1) Series Surface and acceptance test preparation of superconducting cavities for the European Xfel (XFEL/A - D) JUNE 30, 2009

MOP042	Quality Control and Processes Optimization for the EXFEL Superconducting Cavities Series Production at Ettore Zanon spa	cavity, controls, operation, SRF	208
	L. Facci, D. Rizzetto Ettore Zanon S.p.A., Nuclear Division, Schio, Italy G. Corniani Ettore Zanon S.p.A., Schio, Italy A. Matheisen DESY, Hamburg, Germany P. Michelato, L. Monaco INFN/LASA, Segrate (MI), Italy
	The construction of the European XFEL forced the first mass production of Niobium bulk SRF cavities. In this context Ettore Zanon S.p.A. built a fully new facility designed to produce four fully treated and He tank equipped cavities per week, ready to be tested at DESY. The facility already reached the foreseen production rate. The guarantee of the highest quality of the resonators produced requires a very strict quality control plan. At the same time, the requirements of the industrial production in terms of time, cost and productivity must be satisfied. As a consequence processes must be standardized and working times optimized. In the following, after the description of the production facility, we would like to highlight and discuss the strategies and arrangements adopted in the various critical fields (clean room, vacuum, etc.) to ensure the foreseen results. Moreover correlation between cavities performances and production cycle parameters will be investigated and discussed.

MOP044	Performance Characteristics of Jefferson Lab’s New SRF Infrastructure	SRF, cavity, cryomodule, cryogenics	216
	C.E. Reece, P. Denny, A.V. Reilly JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. In the past two years, Jefferson Lab has reconfigured and renovated its SRF support infrastructure as part of the Technology and Engineering Development Facility project, TEDF. The most significant changes are in the cleanroom and chemistry facilities. We report the initial characterization data on the new ultra-pure water systems, cleanroom facilities, describe the reconfiguration of existing facilities and also opportunities for flexible growth presented by the new arrangement.

MOP047	Set up of Production Line for EXFEL Beam Position Monitor and Quadrupol Units for Cavity String Assembly at CEA	alignment, controls, quadrupole, status	224
	M. Schalwat, M. Koepke, A. Matheisen, H. Weitkämper DESY, Hamburg, Germany
	The super conducting (s.c.) accelerator models of the EXFEL consist of eight s.c. resonators, one s.c. quadrupol magnet and one beam position monitor. These components are connected inside ISO 4 cleanroom at CEA Saclay to a so called cavity string under the guidance of the XFEL WP 09 activities. The eight s.c. cavities are handed from DESY to CEA for string assembly after successful RF test. The beam- position monitor and Quadrupol units (BQU) are assembled and cleaned in the DESY cleanroom at DESY Hamburg to the same standard’s of cleanliness as requested for s.c. Cavities. The completed BQU units are handed over to CEA IRFU / WP 9 in “ready for installation to cavity string“ status. The setup of infrastructure, the qualification of processes and transport as well as the ramp up to a delivery rate of 1 BQU per week will be presented.

MOP051	The Statistics of Industrial XFEL Cavities Fabrication at Research Instruments	cavity, target, controls, status	234
	A.A. Sulimov, J.H. Thie DESY, Hamburg, Germany M. Pekeler, D. Trompetter RI Research Instruments GmbH, Bergisch Gladbach, Germany
	Serial production of superconducting cavities for European-XFEL was successfully started at Research Instrument (RI) at the end of last year. The production rate (3-4 cavities a week) allows us to summarize the results and present the statistics of industrial cavity fabrication. Many parameters have been traced during different steps of cavity production. The most interesting of them, as cavity length, frequency, field flatness and eccentricity, are presented and discussed.
	Poster MOP051 [0.769 MB]

MOP057	Developments and Tests of a 700 MHz Cryomodule for the Superconducting Linac of MYRRHA	cavity, cryomodule, linac, cryogenics	250
	F. Bouly CERN, Geneva, Switzerland S. Berthelot, J.-L. Biarrotte, M. El Yakoubi, C. Joly, J. Lesrel, E. Rampnoux IPN, Orsay, France A. Bosotti, R. Paparella, P. Pierini INFN/LASA, Segrate (MI), Italy
	Funding: This work is being supported by the European Atomic Energy Community’s EURATOM) Seventh Framework Programme under grant agreement n°269565(MAX project). The MYRRHA (“Multi-purpose Hybrid Research reactor for High-tech Applications”) project aims at the construction of a new flexible fast spectrum research reactor. This reactor will operate as an Accelerator Driven System demonstrator. The criticality will be sustained by an external spallation neutron flux; produced thanks to a 600 MeV high intensity proton beam. This CW beam will be delivered by a superconducting linac which must fulfil very stringent reliability requirements. In this purpose, the accelerator design is based on a redundant and fault-tolerant scheme to enable the rapid mitigation of RF failures. To carry out “real scale” reliability-oriented experiments a prototype of cryomodule was developed by INFN Milano and installed at IPN Orsay. The module holds a 700 MHz 5-cell elliptical cavity (βg = 0.47) equipped with its blade frequency tuner. Several tests were carried out to commission the experimental set-up. We review here the obtained results and the lessons learnt by operating this module, as well as the on-going developments.

MOP059	Management for the Long-Term Reliability of the Diamond Superconducting RF Cavities	cavity, SRF, ion, electron	255
	P. Gu, C. Christou, M.P. Cox, S.A. Pande, A.F. Rankin, H.S. Shiers, A.V. Watkins Diamond, Oxfordshire, United Kingdom
	Diamond started operation with users in January 2007 and the Diamond storage ring superconducting RF cavities used to be the largest single contributor to unplanned beam trips. Extensive effort has been dedicated to understand and improve the long-term stability of the SRF cavities. Our experience shows that the long-term stability of superconducting RF cavities relies heavily on the surface conditions. Gases keep accumulating on the cold surfaces with time due to its huge cryo-pumping capacity. The integral effect will ultimately lead to fast vacuum trips during operation. In Diamond, we have developed a systematic approach to control the long-term stability of the SRF cavities. We will discuss here our approach and also present the future work that should be completed.

MOP062	Production of 500 MHz SRF Modules the KEKB-type for Taiwan Photon Source	SRF, cavity, niobium, operation	263
	Ch. Wang, L.-H. Chang, M.H. Chang, L.J. Chen, F.-T. Chung, M.-C. Lin, Y.-H. Lin, Z.K. Liu, C.H. Lo, M.H. Tsai, T.-T. Yang, M.-S. Yeh, T.-C. Yu NSRRC, Hsinchu, Taiwan T. Furuya, K. Hara, T. Honma, A. Kabe, Y. Kojima, S. Mitsunobu, Y. Morita, H. Nakai, K. Nakanishi, M. Nishiwaki, S. Takano KEK, Ibaraki, Japan F. Inoue, K. Sennyu, T. Yanagisawa MHI, Hiroshima, Japan
	The KEKB-type single-cell 500-MHz superconducting radio frequency (SRF) modules have been selected to power the 3 GeV, 500 mA, storage ring of the constructing Taiwan Photon Source (TPS) at National Synchrotron Radiation Research Center (NSRRC). The design target is to routinely deliver RF forward power up to 300 kW, CW, to single SRF module with highly reliable operation. Three sets of SRF modules have been successfully produced under a tight collaboration with High Energy Accelerator Research Organization (KEK) and Mitsubishi Heavy Industries Ltd. (MHI), after obtaining the technology transfer from KEK. MHI is responsible for the mechanical fabrication and cryo-module assembly, KEK for the surface and RF treatments of the niobium cavities, high power input couplers and HOM dampers and for the liquid-helium tests of the cryo-modules, and NSRRC for the electronic/diagnostic system, final assembly and system integration, high power horizontal test, and reliable test. This work reports the results obtained during the production of these three SRF modules at KEK and NSRRC.

MOP063	Mature Operation of CESR-Type 500-MHz SRF Module at Taiwan Light Source	SRF, operation, cavity, cryogenics	266
	Ch. Wang, L.-H. Chang, M.H. Chang, L.J. Chen, F.-T. Chung, M.-C. Lin, Y.-H. Lin, Z.K. Liu, C.H. Lo, M.H. Tsai, T.-T. Yang, M.-S. Yeh, T.-C. Yu NSRRC, Hsinchu, Taiwan
	The Cornell-type 500-MHz SRF module has been routinely operated since the end of 2004 to power the 1.5 GeV Taiwan Light Source with 360 mA in top-up mode. A new record of SRF operation with mean time between failures (MTBF)up to 800 hr has been achieved in the 1st half of 2013 that is compatible with the best operational record of room temperature cavities ever made in the same machine. To meet the user’s strict requirements on highly operational reliability, developing in advanced diagnostic instrumentation together with user-friendly event logging software does never stop. Here, we review our SRF operational experience in last 9 years.

MOP064	Operational Experience with the SOLEIL Superconducting RF System	cavity, cryogenics, operation, HOM	269
	P. Marchand, J.P. Baete, R.C. Cuoq, H.D. Dias, M. Diop, J.L. Labelle, R. Lopes, M. Louvet, C.M. Monnot, S. Petit, F. Ribeiro, T. Ruan, R. Sreedharan, K. Tavakoli SOLEIL, Gif-sur-Yvette, France
	In the SOLEIL storage ring, two cryomodules provide to the electron beam an accelerating voltage of 3-4 MV and a power of 575 kW at 352 MHz. Each cryomodule contains a pair of superconducting cavities, cooled with liquid Helium at 4K, which is supplied by a single 350 W cryogenic plant. The RF power is provided by 4 solid state amplifiers, each delivering up to 180 kW. The parasitic impedances of the high order modes are strongly mitigated by means of four coaxial couplers, located on the central pipe connecting the two cavities. Seven years of operational experience with this system as well as its upgrades are reported.

MOP067	Results From Initial Tests of the 1st Production Prototype β=0.29 and β=0.53 HWR Cavities for FRIB	cavity, linac, target, cryomodule	280
	J.P. Ozelis, C. Compton, K. Elliott, M. Hodek, M. Leitner, I.M. Malloch, D. Miller, S.J. Miller, D. Norton, R. Oweiss, J. Popielarski, L. Popielarski, A.P. Rauch, K. Saito, G.J. Velianoff, D.R. Victory FRIB, East Lansing, USA
	Funding: Work supported by US DOE Cooperative Agreement DE-SC0000661 and Michigan State University The first prototypes of the β=0.53 and β=0.29 HWR production design cavities for FRIB were fabricated early this year by Roark Manufacturing Company and delivered to MSU. These cavities have undergone an extensive evaluation program to verify both mechanical and RF performance before proceeding with fabrication of a pre-production run of 10 cavities. Results from physical inspections, warm RF measurements, chemical processing, and cryogenic vertical testing will be presented.

MOP073	IHEP 1.3 GHz Low Loss Large Grain 9-cell Cavity Fabrication, Processing and Test	cavity, HOM, SRF, niobium	305
	J.Y. Zhai, J. Gao, S. Jin, Z.Q. Li, Y. Liu, Z.C. Liu, Z.H. Mi, X.H. Peng, T.X. Zhao, H.J. Zheng IHEP, Beijing, People's Republic of China C.A. Cooper, C.M. Ginsburg, T.N. Khabiboulline, A.M. Rowe, D.A. Sergatskov Fermilab, Batavia, USA J.X. Wang, H. Yu, H. Yuan BIAM, Beijing, People's Republic of China
	The combination of the low-loss shape and large grain niobium material is expected to be the possible way to achieve higher gradient and lower cost for ILC 9-cell cavities, and will be essential for the ILC 1 TeV upgrade. As the key component of the “IHEP 1.3 GHz SRF Accelerating Unit Project”, a low-loss shape 9-cell cavity with full end groups using Ningxia large grain niobium (IHEP-02) was fabricated at IHEP in 2012. The cavity was processed (CBP and EP) and tested at FNAL. The cavity processing,test performance and gradient limitation is reported in this paper. We will weld the helium vessel, assemble the magnetic shield and install the cavity to IHEP ILC-TC1 cryomodule.

MOP074	Design and Construction of the Main Linac Cryomodule for the Energy Recovery Linac Project at Cornell	linac, cryomodule, alignment, cryogenics	308
	R.G. Eichhorn, B. Bullock, J.V. Conway, Y. He, T.I. O'Connel, P. Quigley, D.M. Sabol, J. Sears, E.N. Smith, V. Veshcherevich Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Cornell University has been designing and building superconducting accelerators for various applications for more than 50 years. Currently, an energy-recovery linac (ERL) based synchrotron-light facility is proposed making use of the existing CESR facility. As part of the phase 1 R&D program funded by the NSF, critical challenges in the design were addressed, one of them being a full linac cryo-module. It houses 6 superconducting cavities- operated at 1.8 K in continuous wave (CW) mode - with individual HOM absorbers and one magnet/ BPM section. Pushing the limits, a high quality factor of the cavities and high beam currents (2*100 mA)are targeted. We will present the design of the main linac module (MLC) being finalized recently, its cryogenic features and report on the status of the fabrication which started in late 2012

MOP077	Cryomodule Component Development for the APS Upgrade Short Pulse X-Ray Project	cavity, cryomodule, HOM, alignment	314
	J.P. Holzbauer, J.D. Fuerst, A. Nassiri, Y. Shiroyanagi, B.K. Stillwell, G.J. Waldschmidt, G. Wu ANL, Argonne, USA G. Cheng, J. Henry, J.D. Mammosser, J. Matalevich, J.P. Preble, R.A. Rimmer, H. Wang, K.M. Wilson, M. Wiseman, S. Yang JLAB, Newport News, Virginia, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CHI1357 at ANL and under U.S. DOE Contract No. DE-AC05-06OR23177 at Jefferson Lab. The short pulse x-ray (SPX) part of the Advanced Photon Source Upgrade calls for the installation of a two-cavity cryomodule in the APS ring to study cavity-beam interaction, including HOM damping and cavity timing and synchronization. Design of this cryomodule is underway at Jefferson Lab in collaboration with the APS Upgrade team at ANL. The cryomodule design faces several challenges including tight spacing to fit in the APS ring, a complex set of cavity waveguides including HOM waveguides and dampers enclosed in the insulating vacuum space, and tight alignment tolerances due to the APS high beam-current (up to 150 mA). Given these constraints, special focus has been put on modifying existing CEBAF-style designs, including a cavity tuner and alignment scheme, to accommodate these challenges. The thermal design has also required extensive work including coupled thermal-mechanical simulations to determine the effects of cool-down on both alignment and waveguides. This work will be presented and discussed in this paper.

MOP078	Horizontal Testing of a Dressed Deflecting Mode Cavity for the APS Upgrade Short Pulse X-Ray Project	cavity, controls, operation, photon	321
	J.P. Holzbauer, N.D. Arnold, T.G. Berenc, D.J. Bromberek, J. Carwardine, N.P. Di Monte, J.D. Fuerst, A.E. Grelick, D. Horan, J.A. Kaluzny, J.W. Lang, H. Ma, T.L. Mann, D.A. Meyer, M.E. Middendorf, A. Nassiri, Y. Shiroyanagi, J.H. Vacca, G.J. Waldschmidt, R.D. Wright, G. Wu, Y. Yang, A. Zholents ANL, Argonne, USA E.R. Harms, W. Schappert Fermilab, Batavia, USA J.D. Mammosser JLAB, Newport News, Virginia, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CHI1357. The short pulse x-ray (SPX) part of the Advanced Photon Source (APS) Upgrade is an effort to enhance time-resolved experiments on a few-ps-scale at the APS. The goal of SPX is the generation of short pulses of x-rays for pump-probe time-resolved capability using superconducting rf (SRF) deflecting cavities. These cavities will create a correlation between longitudinal position in the electron bunch and vertical momentum. The light produced by this bunch can be passed through a slit to produce a pulse of light much shorter (1-2 ps instead of 100 ps) than the bunch length at reduced flux. An SPX cavity has been tested with a helium vessel and tuner. In addition to studying rf performance with more realistic cooling, this test allowed integration and operation of many systems designed for SPX cryomodule in-ring operation. These systems included an APS-constructed 5 kW, 2.815 GHz amplifier, a digital low-level rf controller system designed and fabricated in collaboration with LBNL, a cavity tuner, and instrumentation systems designed for the existing APS infrastructure. Cavity performance and subsystem performance will be reported and discussed in this paper. A. Zholents et al., NIM A 425, 385 (1999). ** A. Nassiri et al., “Status of the Short-Pulse X-Ray Project at the Advanced Photon Source,” IPAC 2012, New Orleans, LA, May 2012.

MOP079	Design and Test of a Cryogenic Seal for Rectangular Waveguide Using VATSEAL Technology	cryogenics, superconducting-RF, detector, controls	325
	J.D. Fuerst, J.P. Holzbauer, J.A. Kaluzny, C.R. Montiel, Y. Shiroyanagi, B.K. Stillwell ANL, Argonne, USA
	Funding: This work was supported by the U. S. Department of Energy, Office of Science, under contract No. DE-AC02-06CH11357. A commercially available rectangular metal seal from VAT Vacuum Valves AG has been evaluated and cold tested as a possible cryogenic seal for srf cavities. A program of analysis and cryogenic testing was undertaken to evaluate seal parameters and suitability. Seal line loads, bolt torque and resultant flange/seal deformation at low temperature and during thermal cycling were calculated both statically and via time-dependent numerical simulation to confirm the mechanical integrity of the flange/seal system. Cold testing of flange/waveguide assemblies included thermal shocks in liquid nitrogen and realistic cool-downs below the λ point. Acceptable seal performance has been demonstrated under all test conditions although seal joint assembly is sensitive to details including bolt torque, flange flatness, and surface finish.

MOP080	Design of a New Horizontal Test Cryostat for SCRF Cavities at the Uppsala University	cavity, cryomodule, radiation, operation	328
	T. Junquera, P. Bujard, N.R. Chevalier, J.P. Thermeau Accelerators and Cryogenic Systems, Orsay, France L. Hermansson, M. Noor, R.J.M.Y. Ruber, R. Santiago Kern Uppsala University, Uppsala, Sweden H. Saugnac IPN, Orsay, France
	At Uppsala University, the FREIA facility for research and development of new accelerators and associated instrumentation, is presently in construction. Associated to a new Helium Liquefier, a Horizontal Test Cryostat will be used for high power RF tests of completely equipped SC cavities. This paper presents the main characteristics of the cryostat and the associated cryogenic distribution system. Two types of cavities have been considered for test purpose: SC elliptical cavities for future free electron lasers and SC cavities for high intensity proton accelerators (i.e. SC spokes). A special valve box including a subcooling stage and power coupler cooling with supercritical Helium supply have been designed, for temperature operation ranging from 2K to 4.2 K. This facility will play an essential role in the development and test of cavities, couplers and cryomodules for the ESS project. High power RF sources will be installed in order to allow unique and complete tests of spoke cavities and cryomodules at high nominal peak power.

MOP082	Development and Test of a New Cryostat Module for the Injector of the S-DALINAC*	electron, operation, cavity, linac	334
	T. Kürzeder, J. Conrad, F. Hug, N. Pietralla, A. Richter, S.T. Sievers TU Darmstadt, Darmstadt, Germany R.G. Eichhorn Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: *This work is supported by the DFG through the Collaborative Research Center SFB 634. The present injector of the superconducting Darmstadt electron linear accelerator S-DALINAC provides an electron beam of up to 10 MeV kinetic energy and up to 60 μA current in continuous wave operation. A new cryostat module has been constructed to replace the actual one in order to provide higher beam energies of up to 14 MeV and currents of up to 250 μA for nuclear resonance fluorescence experiments at the Darmstadt High Intensity Photon Setup (DHIPS). As before two 20-cell superconducting microwave cavities will be operated at an acceleration frequency of 3 GHz in a liquid helium bath at 2 K. For the injector upgrade two new elliptical 20-cell niobium cavities were also manufactured and in addition a third spare one. The rf power is transferred to the cavities by an also newly developed waveguide-transition line and input couplers. We report on the construction of the cryostat module and its components and present the results of a first cooling-down procedure.

MOP084	ESS Cryomodules for Elliptical Cavities	cryomodule, cryogenics, cavity, operation	341
	G. Olivier, J.P. Thermeau IPN, Orsay, France P. Bosland CEA/IRFU, Gif-sur-Yvette, France C. Darve ESS, Lund, Sweden
	The European Spallation Source will be the world's most powerfull neutron source. IPN Orsay undertakes the development of the ESS linac cryomodules for both medium and high beta elliptical cavities which constitute the high energy section. A medium beta technical demonstrator will be built in a first time. The cryomodules are composed of 4 superconducting cavities cooled at 2K. The cold mass assembly is hanged in an intermediate structure located inside the vacuum vessel. A 50K fixed temperature is implemented by the mean of an aluminium shield. Each cryomodule is connected to the cryogenic distribution line. The vacuum vessel is 6.3m long and has a 1.2m diameter. The poster describes the general design,the solutions implemented, the characteristics of the main components and the mechanical/thermal calculations .

MOP085	Status of the Superconducting Proton Linac (SPL) Cryomodule	cavity, cryogenics, operation, linac	345
	V. Parma, R. Bonomi, O. Capatina, J.K. Chambrillon, E. Montesinos, K.M. Schirm, A. Vande Craen, G. Vandoni, R. van Weelderen CERN, Geneva, Switzerland G. Devanz CEA/IRFU, Gif-sur-Yvette, France P. Duchesne, P. Duthil, S. Rousselot IPN, Orsay, France
	The Superconducting Proton Linac (SPL) is an R&D effort conducted by CERN in partnership with other international laboratories, aimed at developing key technologies for the construction of a multi-megawatt proton linac based on state-of-the-art SRF technology. Such an accelerator would serve as a driver in new physics facilities for neutrinos and/or radioactive ion beams. Amongst the main objectives of this effort, are the development of 704 MHz bulk niobium β=1 elliptical cavities (operating at 2 K and providing an accelerating field of 25 MV/m) and the test of a string of cavities integrated in a machine-type cryo-module. In an initial phase, only four out of the eight cavities of the SPL cryo-module will be tested in a half- length cryo-module developed for this purpose, which nonetheless preserves the main features of the full size machine. This paper presents the final design of the cryo-module and the status of the construction of the main cryostat parts. Preliminary plans for the assembly and testing of the cryo-module at CERN are presented and discussed.

MOP089	Design of the ESS Spoke Cryomodule	cryomodule, cavity, operation, cryogenics	357
	D. Reynet, S. Bousson, S. Brault, P. Duchesne, P. Duthil, N. Gandolfo, G. Olry, E. Rampnoux IPN, Orsay, France
	The European Spallation Source (ESS) project brings together 17 European countries to develop the world’s most powerful neutron source feeding multidisplinary researches. The superconducting part of the linear accelerator consists in 59 cryomodules housing different superconducting radiofrequency (SRF) resonators among which 28 paired β=0.5 352.2 MHz SRF niobium double Spoke cavities, held at 2K in a saturated helium bath. A prototype Spoke cryomodule with two cavities equipped with their 300kW RF power couplers is now being designed and will be constructed and tested at full power by the end of 2015 for the validation of all chosen technical solutions. It integrates all the interfaces necessary to be operational within a linac machine. Its assembly requires dedicated tooling and procedures in and out of a clean room. The design takes into account an industrial approach for the management of the fabrication costs. This prototype will have to guarantee an accelerating field of 8MV/m while optimizing the energy consumption and will aim at assessing the maintenance operations issues. We propose to present the design of this cryomodule and its related tooling.

TUIOC05	Purification of 6 GHz Cavities by Induction Heating	cavity, induction, niobium, SRF	419
	A.A. Rossi, A. Battistello, M. Checchin, V. Palmieri, S. Stark, F. Stivanello, R.K. Thakur, G. Yu INFN/LNL, Legnaro (PD), Italy
	We have developed an innovative technique for purification of bulk-Nb 6GHz RF cavities under ultra-high vacuum (UHV) system. The main advantages of 6 GHz bulk-Nb cavities are saving cost, materials and time to collect statistics of surface treatments and RF test. Cavities are RF tested before and after high temperature treatment under UHV conditions. Induction heating method is used to anneal the cavity at temperatures higher than 2000°C and close to the melting point of Nb for less than a minute while few seconds at maximum temperature. Before RF test and UHV annealing, the surface treatment processes like tumbling, chemical, electro-chemical (such as BCP and EP), ultrasonic cleaning and high pressure rinsing (HPR) have been employed. This kind of Nb 6 GHz cavity purification allow to reduce hydrogen, oxygen and other elemental impurities content, which effects on cavity Q-factor degradation, by a rapid annealing over 2000°C and a subsequent rapid reduction at room temperature.
	Slides TUIOC05 [42.171 MB]

TUP007	Vortex Penetration Field in the Multilayered Coating Model	cavity, superconductivity, electromagnetic-fields	430
	T. Kubo, T. Saeki KEK, Ibaraki, Japan Y. Iwashita Kyoto ICR, Uji, Kyoto, Japan
	A multilayered structure with a single superconductor layer and a single insulator layer deposited on a bulk superconductor is studied. General formulae for the vortex penetration-field of the superconductor layer and the magnetic field on the bulk superconductor which is shielded by the superconductor and insulator layers are derived with a rigorous calculation of the magnetic field attenuation in the multilayered structure. The formulae depend not only on the material and the thickness of the superconductor layer but also on the thickness of the insulator layer. The results can be applied to superconducting accelerating cavities with the multilayered structure. Using the formulae, a combination of the thicknesses of superconductor and insulator layers to enhance the RF breakdown field limits can be found for any given materials. (Submitted on 25 Apr 2013) T. Kubo, Y. Iwashita and T. Saeki, arXiv:1304.6876 [physics.acc-ph](Submitted on 25 Apr 2013); arXiv:1306.4823 [physics.acc-ph](Proc. of IPAC13); arXiv:1307.0583 [physics.acc-ph](Proc. of SRF2013)

TUP014	Fast Table Top Niobium Hydride Investigations Using Direct Imaging in a Cryo-Stage	niobium, cavity, cryogenics, laser	447
	F.L. Barkov, A. Grassellino, A. Romanenko Fermilab, Batavia, USA
	Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy. Performance of niobium SRF cavities can be strongly affected by hydrogen segregation into lossy niobium hydrides as known for "hydrogen Q disease" at higher concentration of dissolved H and may be a reason for the "high field Q slope" at lower concentrations. With the use of optical cryostat and laser confocal microscope we have developed a "table top technique" for direct observation of hydride precipitation, and studied formation, morphology, and time evolution of hydrides after different treatments used for cavities. Our results show that hydrides can form at the niobium surface at 90-180K depending mainly on H concentration and the cooldown rate. A lot of H is absorbed by bulk niobium during mechanical polishing, which leads to the formation of very large (>10 microns) hydrides. Both EP and BCP do not influence H concentration significantly provided that temperature during treatments is kept below 15C. 800C degassing reduces H concentration and precludes large hydride precipitation. 120C baking and mechanical deformation do not change H concentration but affect hydride precipitation through their influence on the number of nucleation centers and H binding defects.

TUP029	Heat Treatment of SRF Cavities in a Low-Pressure Atmosphere	cavity, SRF, niobium, resonance	487
	D. Gonnella, F. Furuta, M. Liepe Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: NSF Recent results from FNAL on baking superconducting RF cavities at high temperatures in a low-pressure atmosphere of a few mTorr indicate that such treatments can increase the medium field quality factor. In this paper we report on studies from Cornell, giving new insight into the mechanism behind this effect.

TUP043	Nanostructural TEM/STEM Studies of Hot and Cold Spots in SRF Cavities	niobium, cavity, electron, SRF	504
	Y. Trenikhina, J. Zasadzinski IIT, Chicago, USA A. Romanenko Fermilab, Batavia, USA
	Direct TEM/STEM imaging and spectroscopic chemical characterization by EELS/EDS of the surface of the SRF cavity cutouts before and after the treatments (e.g. in situ mild vacuum bake and rinsing with hydrofluoric acid) down to subnanometer scale is implemented to correspond the changes in niobium surface to the SRF performance of the cavities. We also report current results of the direct search, using cryogenic TEM stage, for suggested phase transformations in the niobium-hydrogen system* on “hot” and “cold” spot cavity cutouts, which may help clarifying the mechanism of the high field Q slope and its empirical cure. *A. Romanenko, F. Barkov, L. D. Cooley, A. Grassellino, Supercond. Sci. Technol. 26 (2013) 035003.

TUP048	Preparations and VT Results of ERL7-cell at Cornell	cavity, cryomodule, target, radiation	521
	F. Furuta, B. Bullock, R.G. Eichhorn, B. Elmore, A. Ganshin, G.M. Ge, G.H. Hoffstaetter, J.J. Kaufman, M. Liepe, J. Sears Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	We have fabricated 7 ERL 7-cell cavities for Cornell ERL project. 4 nu-stiffened and 3-stiffened cavities have been fabricated in house so far. Specification values of our 7-cell is 16.2MV/m with Qo of 2.0·10¹⁰ at 1.8K. In this report, we will describe our surface treatments recipe which is based on BCP and the results of vertical tests of these 7-cell cavities.

TUP051	Horizontal High Pressure Water Rinsing for Performance Recovery	cavity, cryomodule, operation, factory	527
	Y. Morita, K. Akai, T. Furuya, A. Kabe, S. Mitsunobu, M. Nishiwaki KEK, Ibaraki, Japan
	Eight superconducting accelerating cavities were operated for more than ten years at the KEKB machine. Those cavities are also used at SuperKEKB. During the KEKB operation, Q values of some cavities were degraded. Cause of the degradation was contamination by air dusts at a repair of vacuum seals or a gasket replacement of input couplers. So far, those degradations are acceptable for the SuperKEKB operation, however, further degradation will make the operation unstable and, in the worst case, make it impossible. High pressure rinsing (HPR) is an effective method to clean the cavity surface. In order to apply HPR, however, the cavity has to be disassembled from a cryomodule. The disassembly takes time and costs. Furthermore, re-sealed vacuum flanges bring the risk of vacuum leakage again. Therefore we have developed a horizontal HPR. This method applies a high pressure water jet that is inserted horizontally into the cavity in the cryomodule. The wasted water is extracted with an aspirator. This method does not require the disassembly. We applied the horizontal HPR to our degraded cavity. Its RF performance has been successfully recovered.

TUP056	Industrialization of European XFEL Preparation Cycle “BCP Flash” at Ettore Zanon Company	cavity, controls, acceleration, pick-up	547
	A. Matheisen, N. Krupka, M. Schalwat, A. Schmidt, W. Singer, N. Steinhau Kühl, B. van der Horst DESY, Hamburg, Germany G. Corniani Ettore Zanon S.p.A., Schio, Italy P. Michelato, L. Monaco INFN/LASA, Segrate (MI), Italy
	In the Specification for XFEL Cavity preparation (R1) two different preparation sequences are presented. Ettore Zanon Company as one of the two companies contracted for XFEL cavity production and preparation has chosen the so called BCP flash cycle. To fulfill the requested work flow and quality of infrastructure and processes, the company set up a complete new infrastructure in refurbished fabrication halls. The layout of the facility, set up of work flow of preparation and test results of resonators processed by E.Zanon in their infrastructure will be reported. (R1) Series Surface and acceptance test preparation of superconducting cavities for the European Xfel (XFEL/A - D) JUNE 30, 2009

TUP058	Recent Findings on Nitrogen Treated Niobium	niobium, cavity, SRF, solenoid	558
	R.G. Eichhorn, A. Ganshin, A. Holmes, J.J. Kaufman, S.R. Markham, S. Posen, E.N. Smith Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Recent findings on Nitrogen treated Niobiums Based on recent findings at Fermilab, Cornell investigated the role of Nitrogen being present during the cavity hydrogen degassing process. We treated several samples at different temperatures being exposed to nitrogen between 10 minutes and 3 hours at pressures around 15 mbar as well as single cell cavities. This contribution will summarize our findings from surface analysis, Tc measurements and cavity Qs, addressing the question, if such a process can form Niobium-Nitride.

TUP059	TM-Furnace Qualification at Cornell	cavity, SRF, cryomodule	561
	F. Furuta, B. Bullock, R.G. Eichhorn, A. Ganshin, G.M. Ge, G.H. Hoffstaetter, J.J. Kaufman, M. Liepe, J. Sears Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Cornell's SRF group had new vacuum furnace for hydrogen degassing of SRF Nb cavity. Systematic study and testing have been done to qualify this new furnace. We will report the results of those qualification tests include cavity bake and vertical testing.

TUP062	Application of In-Vacuum Infrared Pyrometry During Fabrication of European XFEL Niobium Cavities	cavity, operation, electron, niobium	570
	L. Monaco, P. Michelato, D. Sertore INFN/LASA, Segrate (MI), Italy V. Battista, G. Corniani, M. Festa Ettore Zanon S.p.A., Schio, Italy C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy
	A technique to measure the temperature of Niobium components in vacuum during Electron Beam Welding (EBW) operation is presented and results obtained on the large scale cavity production for the European XFEL are discussed. During the EBW process, the knowledge of the components temperature during the welding operation could help both for the better choice of the welding parameters and for the optimization of the production cycle. In collaboration with the Italian firm Ettore Zanon (EZ), we developed a system able to measure the temperature of Nb components in vacuum during EBW operation using a IR pyrometer placed outside the vacuum chamber through an appropriate vacuum viewport. In the paper the experience of this device during the production of Nb components for the XFEL 1.3 GHz cavity production is discussed.

TUP067	Hydrogen Saturation and the Thermal Conductivity of Superconducting Niobium	niobium, cavity, superconductivity, lattice	589
	S.K. Chandrasekaran MSU, East Lansing, USA T.R. Bieler Michigan State University, East Lansing, USA C. Compton FRIB, East Lansing, USA N.T. Wright (MSU), East Lansing, USA
	Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics, through Grant No. DE-S0004222 The thermal conductivity k of Nb at less than 3 K is dominated by phonon transport. In Nb with sufficiently few lattice imperfections, a maximum in k occurs at 1.8 K, called the phonon peak (PP). A large PP is desired to reduce potential local hot spots and contributes to an increased Q factor. The magnitude of the PP is sensitive to SRF cavity manufacturing processes. The effect of interstitial hydrogen on the magnitude of the PP is examined by subjecting two bicrystal Nb specimens to 300 C for 1 h in a 75% H2, 25% N2 atmosphere at 0.5 atm. Prior to hydrogen infusion, specimen 1 was heated to 800 C for 2 h, while specimen 2 was heated to 1100 C for 4 h. Both specimens displayed a 25% reduction in the PP due to the additional hydrogen, independent of their crystal orientations and heat treatment histories. An 800 C vacuum heating for 2 h was found to be sufficient to recover the PP in specimen 1, while an 1100 C heating for 4 h was required to recover the PP in one of the grains of specimen 2. The results suggest that hydrogen trapped in the Nb lattice will degas when the Nb is heated to at least the temperature to which it was heated at prior to the hydrogen infusion step.

TUP071	Development of Nb3Sn Cavity Vapor Diffusion Deposition System	niobium, cavity, impedance, controls	603
	G.V. Eremeev, W.A. Clemens, K. Macha, H. Park, R.S. Williams JLAB, Newport News, Virginia, USA H. Park ODU, Norfolk, Virginia, USA
	Funding: Work supported by DOE. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Alternative BCS superconductors with the superconducting critical temperature higher than that of niobium theoretically surpass the limitations of niobium. The feasibility of technology has been demonstrated at 1.5 GHz with Nb3Sn vapor deposition technique at Wuppertal University. The benefit at these frequencies is more pronounced at 4.2 K, where Nb3Sn coated cavities show RF resistances an order of magnitude lower than that of niobium. At Jefferson Lab we started the development of Nb3Sn vapor diffusion deposition system within an R&D development program towards compact light sources. Here we present the current progress of the system development.

TUP073	Niobium Coatings for the HIE-ISOLDE QWR Superconducting Accelerating Cavities	cavity, niobium, cathode, SRF	611
	N.M. Jecklin, S. Calatroni, L.M.A. Ferreira, I. Mondino, A. Sublet, M. Therasse, W. Venturini Delsolaro CERN, Geneva, Switzerland B. Delaup EPFL, Lausanne, Switzerland
	The HIE-ISOLDE project is the upgrade of the existing ISOLDE facility at CERN, which is dedicated to the production of a large variety of radioactive ion beams for nuclear physics experiments. A new linac made of 20 β=10.3% and 12 β=6.3% QWR superconducting accelerating cavities at 101 MHz will be built, and in a first phase two cryomodules of 5 high-beta cavities each are scheduled to accelerate first beams in 2015. The cavities are made of a copper substrate, with a sputter-coated superconductive niobium layer, operated at 4.5 K with an accelerating field of 6 MV/m at 10W RF losses (Q0=4.5e8) In this paper we will discuss the baseline surface treatment and coating procedure which allows obtaining the required performance, as well as the steps undertaken in order to prepare series production of the required number of cavities guaranteeing their quality and functionality.

TUP092	MUSICC3D: a Code for Modeling the Multipacting	cavity, electron, simulation, RF-structure	683
	T. Hamelin, M. Chabot, J.-L. Coacolo, J. Lesrel, G. Martinet IPN, Orsay, France
	IPNO has conducted an effort to develop a 3D code for modeling multipacting in RF structures. The MUSICC3D program is using particle in cell method. Based on Runge Kutta method and using relativistic equation of motion, it solves the trajectory of a particle (e-) in the RF field. The integrations over the multi differential Secondary Emission Yield (SEY) (E_in, Alpha_in ,E_out, Alpha_out)) is made with Montecarlo method. Two running modes are available. The first one is using a model of virtual particle (i.e. the charge of a unique particle “rebounding” in the interior of the cavity is made by the product of SEYs occurring at each interaction with the walls). The other one makes generation of a full cascade of individual electrons. Benchmarking calculations have been done with analytical calculations and 2D particle in cell code (MULTIPAC). In all these cases the effects of the different inputs for the multi differential SEY have been investigated. Its intend is to give a guide to determine which precision on the SEY is needed to perform accurate multipacting calculations. Benchmarking with real cavity has been recently started and results with QWR Spiral2 cavities are presented. Hatch, Multipacting Modes etc., Physical Review. Wood, Investigations into Multipactor Breakdown etc., ESA Journal. Geng, Multipacting Simulations etc., Particule Accelerator Conference.

TUP094	Influence of Heat Treatments on Field Emitters on Nb Crystals	cavity, site, status, power-supply	690
	S. Lagotzky, G. Müller Bergische Universität Wuppertal, Wuppertal, Germany A. Matheisen, D. Reschke DESY, Hamburg, Germany
	Funding: Funding by HGF Alliance and the BMBF project 05H12PX6 Systematic investigations of the enhanced field emission (EFE) of HPR-cleaned large grain (LG) and single crystal (SC) Nb samples (Ra < 0.5μm) revealed an exponential increase of the emitter number density N with electric surface field Es and strong activation effects of the remaining particulates. Different types of EFE activation were observed: by high E partially combined with a micro-discharge or by heat treatments (HT) [1]. In cavities, EFE activation might also occur due to enhanced rf losses of particulates. Therefore, we have started a test series with two LG and two SC typically prepared Nb samples (40 μm BCP, 140 μm EP and HPR at DESY). At first all emitters (1 nA) up to Es = 160 MV/m were localized by means of correlated field emission microscopy (FESM). Then systematically varied in-situ HT between 122°C (24 h) and 400°C (2 h) were applied to investigate the activation of emitters due to the change of the natural Nb oxide. For all samples a significant increase of N with stronger HT up to 32 emitters/cm² at 400°C were obtained resulting in some activated emitters already at Es = 40 MV/m. Final SEM images of the activated emitters will also be discussed. [1] A. Navitski et. al, subm. to PRSTAB 2013

WEIOA02	Energetic Condensation Growth of Niobium Films	cavity, ion, lattice, plasma	761
	M. Krishnan, I. Irfan AASC, San Leandro, California, USA
	Funding: The AASC research is supported by the US Department of Energy via several SBIR research grants Energetic Condensation refers to thinfilm growth on a surface using ~100eV ions, versus lower energy deposition using sputtering (~1-10eV with no substrate bias) or still lower energy thermal evaporation. The relatively high incident energy of energetic condensation creates defects and vacancies within the first few atomic layers and enables diffusion to lower free-energy sites in the lattice. Shallow defects migrate to the heated surface and are annihilated, leading to low-defect crystal growth. It has been shown [1] that the purer the film, the closer are its superconducting parameters to those of the bulk metal. Use of cathodic arc plasmas was proposed in 2000 by Langner [TESLA Rep. 2000-15, Ed. D. Proch, DESY 2000], followed by detailed development of the process [2]. AASC picked up from the European Community-Research Infrastructure Activity and has demonstrated very high RRR=541 in Nb films grown on crystal substrates [3]. Ongoing work to coat 1.3GHz copper cavities using cathodic arc plasmas, as well as growth of higher temperature films such as NbTiN, Nb3Sn and MgB2 are described. A related technique for energetic condensation using an ECR plasma source is also described. 1. C. Benvenuti et al, IEEE Trans. Appl. Supercond. 9 (1999) 900 2. R. Russo et al, Supercond. Sci. Technol. 18 (2005) L41-L44 3. M. Krishnan et al, Supercond. Sci. Technol. 24, 115002 (2011)
	Slides WEIOA02 [14.616 MB]

WEIOA03	Nb Sputtered Quarter Wave Resonators for the HIE-ISOLDE	cavity, cathode, niobium, linac	767
	W. Venturini Delsolaro, S. Calatroni, A. D'Elia, B. Delaup, N.M. Jecklin, Y. Kadi, P. Maesen, I. Mondino, A. Sublet, M. Therasse CERN, Geneva, Switzerland A. D'Elia UMAN, Manchester, United Kingdom D.A. Franco Lespinasse, G. Keppel, V. Palmieri, S. Stark INFN/LNL, Legnaro (PD), Italy
	The HIE-ISOLDE superconducting linac will be based on quarter wave resonators (QWRs), made by Niobium sputtering on Copper. The operating frequency at 4.5 K is 101.28 MHz and the required performance for the high beta cavity is 6 MV/m accelerating field for 10 W maximum power dissipation. These challenging specifications were recently met at CERN at the end of a vigorous development program. The paper reports on the progress of the cavity RF performance with the evolution of the sputtering process; it equally illustrates the parallel R&D which is ongoing at CERN and at INFN in the quest for even higher performances.
	Slides WEIOA03 [14.564 MB]

WEIOA04	Nb3Sn for SRF Application	niobium, cavity, SRF, laser	773
	M. Liepe, S. Posen Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	The superconductor Nb3Sn is a promising alternative to standard niobium for SRF applications for two reasons: Its larger superconducting energy gap results in significantly lower BCS surface resistance at typical SRF operating temperatures. Additionally, theoretical predictions suggest that the maximum operating field of Nb3Sn cavities could be twice that of niobium cavities. Early work on a small number of Nb3Sn coated cavities indeed showed 2K to 4.2K quality factors well above what is achievable with niobium, though at accelerating fields below ~10 MV/m only. After many years of worldwide inactivity, Cornell has taken the lead and initiated a new R&D program on Nb3Sn to explore its full potential for SRF applications. New facilities for coating cavities with Nb3Sn have been set up at Cornell, and 1.3 GHz single cell cavities have been coated and tested. This talk presents the Cornell Nb3Sn program, discusses first promising results obtained, and also gives an overview of other Nb3Sn SRF work worldwide.
	Slides WEIOA04 [3.854 MB]

WEIOC02	Multilayers Activities at Saclay / Orsay	niobium, cavity, SRF, superconductivity	789
	C. B. Baumier, G. Martinet IPN, Orsay, France C.Z. Antoine CEA/IRFU, Gif-sur-Yvette, France F. F. Fortuna CSNSM, ORSAY CAMPUS, France J.C. Villegier CEA/INAC, Grenoble Cedex 9, France
	In the investigations on the high gradient SRF cavities, the superconducting multilayer is a promising alternative. The predictions show that an SIS (Superconductor/Isolator/Superconductor) nano-composite could improve the efficiency limited by the bulk Nb it-self used today for accelerating cavities. We start, at the IPNO lab in collaboration with the CSNSM lab (CNRS) and Irfu lab (CEA), an experimental study to test the screening effect on multilayer assemblies. Based on 3rd harmonic magnetometer and a TE011 SRF cavity, measurements of first critical magnetic field HC1 and surface resistance of samples have been performed. Along with these first results, we are starting the development of a MBE deposition. This set-up is devoted to optimise the best organisation of the multilayer to produce the model sample, and to find, in a close future, a realistic solution to apply this technique on an accelerating SRF cavity. Labex P2IO funding
	Slides WEIOC02 [3.035 MB]

THIOA02	The Challenge to Assemble 100 Cryomodules for the European E-XFEL	cryomodule, cavity, controls, linac	816
	C. Madec CEA, Gif-sur-Yvette, France S. Berry, J.-P. Charrier, M. Fontaine, Y. Gasser, O. Napoly, C.S. Simon, T.V. Vacher, B. Visentin CEA/DSM/IRFU, France P. Charon, C. Cloué, G. Monnereau, J.L. Perrin, D. Roudier, Y. Sauce, T. Trublet CEA/IRFU, Gif-sur-Yvette, France
	As In-Kind contributor to the E-XFEL project, CEA is committed to the integration on the Saclay site of the 100 cryomodules (CM) of the superconducting linac as well as to the procurement of miscellaneous parts including 31 cold beam position monitors (BPM) of the re-entrant type. The assembly infrastructure has been renovated from the previous Saturne Synchrotron Laboratory facility: it includes a 200 m2 clean room complex with 112 m2 under ISO4, 1325 m2 of assembly platforms and 400 m2 of storage area. In parallel, CEA has conducted industrial studies and three cryomodule assembly prototyping both aiming at preparing the industrial file, the quality management system and the commissioning of the assembly plant, tooling and control equipment. In 2012, the contract of the integration has been awarded to ALSYOM. The first pre-series modules have been assembled and are being tested at DESY. This paper will present the challenges of the module integration from the preparation phase to the industrial phase.
	Slides THIOA02 [17.641 MB]

THIOA04	Low-Beta Cryomodule Design Optimized for Large-Scale Linac Installations	cryomodule, alignment, solenoid, cryogenics	825
	S.J. Miller, B. Bird, N.K. Bultman, F. Casagrande, A.D. Fox, M.J. Johnson, M. Leitner, T. Nellis, J.P. Ozelis, X. Rao, R.J. Rose, M. Shuptar, K. Witgen, Y. Xu FRIB, East Lansing, Michigan, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. This paper will present most recent design developments at FRIB to optimize low-beta cryomodules for large-scale linac installations. FRIB, which requires the fabrication of 53 cryomodules, has to emphasize ease of assembly and alignment plus low cost. This paper will present experimental results of a novel kinematic rail support system which significantly eases cryomodule assembly. Design choices for mass-production are presented. Results of vibration calculations and measurements on a FRIB prototype cryomodule will be reported.
	Slides THIOA04 [10.842 MB]

THIOB01	CEBAF Upgrade: Cryomodule Performance and Lessons Learned	cryomodule, cavity, linac, controls	836
	M.A. Drury, J. Hogan, C. Hovater, L.K. King, H. Park, J.P. Preble, R.A. Rimmer, H. Wang, M. Wiseman JLAB, Newport News, Virginia, USA G.K. Davis, C.E. Reece JLab, Newport News, Virginia, USA F. Marhauser Muons, Inc, Illinois, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract DE-AC05-06OR23177. The Thomas Jefferson National Accelerator Facility is currently engaged in the 12 GeV Upgrade Project. The goal of the 12 GeV Upgrade is a doubling of the available beam energy of the Continuous Electron Beam Accelerator Facility (CEBAF) from 6 GeV to 12 GeV. The increase in beam energy will largely be due to the addition of ten C100 cryomodules and the associated RF in the CEBAF linacs. These cryomodules are designed to deliver 100 MeV per cryomodule. Each C100 cryomodule contains a string of eight seven-cell, electro-polished, superconducting RF cavities. While an average performance of 100 MV is needed to achieve the overall 12 GeV beam energy goal, the actual performance goal for the cryomodules is an average energy gain of 108 MV to provide operational headroom. All ten of the C100 cryomodules are installed in the linac tunnels and are on schedule to be commissioned by September 2013. Commissioned performance has ranged from 104 MV to 118 MV. In May, 2012, a test of an early C100 achieved 108 MV with full beam loading. This paper will discuss the performance of the C100 cryomodules along with operational challenges and lessons learned for future designs. The U.S. Govt. retains a non-exclusive, paid-up,irrevocable,world-wide license to publish or reproduce this manuscript.
	Slides THIOB01 [2.534 MB]

THIOD02	Faced Issues in ReA3 Quarter-Wave Resonators and Their Successful Resolution	cavity, linac, cryomodule, operation	873
	A. Facco NSCL, East Lansing, Michigan, USA C. Compton, J.L. Crisp, K. Elliott, A. Facco, M. Hodek, M.J. Johnson, M. Leitner, I.M. Malloch, D. Miller, S.J. Miller, D. Morris, D. Norton, R. Oweiss, J.P. Ozelis, J. Popielarski, L. Popielarski, K. Saito, N.R. Usher, G.J. Velianoff, D.R. Victory, J. Wei, K. Witgen, Y. Xu, S. Zhao FRIB, East Lansing, Michigan, USA A. Facco INFN/LNL, Legnaro (PD), Italy
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. The 80.5 MHz, β=0.085 QWR production cavities for the ReA3 project at MSU have initially shown puzzling behavior and unexpected lack of performance. This was due to a combination of design problems and subtle mechanical effects which have been pointed out during a brief but intense testing campaign made by the FRIB SRF group. The same cavities could be eventually refurbished and brought to performance well above original specifications. This work will be presented with emphasis to the technical problems encountered, their diagnosis and the adopted solutions.
	Slides THIOD02 [8.256 MB]

THP005	Characteristics and Fabrication of Spoke Cavities for High-Velocity Applications	cavity, operation, target, superconductivity	902
	C.S. Hopper, J.R. Delayen, H. Park ODU, Norfolk, Virginia, USA J.R. Delayen, H. Park JLAB, Newport News, Virginia, USA
	A 500 MHz, velocity-of-light, two-spoke cavity has been designed and optimized for possible use in a compact light source [1]. Here we present the mechanical analysis and steps taken in fabrication of this cavity at Jefferson Lab. *[1] T. Satogata et al, “Compact Accelerator Design for a Compact Light Source,” IPAC13, Shanghai, China, May 2013.

THP012	Rebuild of Capture Cavity 1 at Fermilab	cavity, cryomodule, operation, SRF	917
	E.R. Harms, T.T. Arkan, E. Borissov, N. Dhanaraj, A. Hocker, Y.O. Orlov, T.J. Peterson, K.S. Premo Fermilab, Batavia, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. The front end of the proposed Advanced Superconducting Test Accelerator at Fermilab employs two single cavity cryomodules, known as ‘Capture Cavity 1’ and ‘Capture Cavity 2’, for the first stage of acceleration. Capture Cavity 1 was previously used as the accelerating structure for the A0 Photoinjector to a peak energy of ~14 Mev. In its new location a gradient of ~25 MV/m is required. This has necessitated a major rebuild of the cryomodule including replacement of the cavity with a higher gradient one. Retrofitting the cavity and making upgrades to the module required significant re-design. The design choices and their rationale, summary of the rebuild, and early test results are presented.

THP024	Lorentz Force Detuning Simulations of Spoke Cavities With Different Stiffening Elements	cavity, simulation, radiation, operation	946
	J.L. Muñoz, F.J. Bermejo ESS Bilbao, Zamudio, Spain
	Lorentz force detuning caused by radiation pressure on the Nb cavity walls is of concern in cavity design and operation since its magnitude can approach the cavity bandwidth. This effect can be reduced using pasive stiffening elements in the cavity. In this work, Lorentz force detuning has been studied by numerical simulations for spoke cavities. Different stiffening elements has been considered. Static and dynamic behaviour have been analyzed by means of 3D static and transient electromagnetic and mechanical coupled finite elements simulations.

THP026	Cage Cavity: A Low Cost, High Performance SRF Accelerating Structure	cavity, SRF, HOM, simulation	950
	J. Noonan, T.L. Smith, M. Virgo, G.J. Waldschmidt ANL, Argonne, USA J.W. Lewellen LANL, Los Alamos, New Mexico, USA
	Funding: Funded by Office of Naval Research. Argonne National Laboratory is operated by UChicago-Argonne LLC for the Department of Energy The Cage Cavity is a new SRF cavity technology using tubes formed into the shape of a solid wall cavity then assembled into a closed volume. The theory is that the cage cavity will form a resonant cavity at RF frequencies below a critical frequency at which the cage structure behaves as a solid structure. Several cage cavity structures have been fabricated and measured that demonstrate good RF properties. Comparison of simulations and measurements for these structures will be discussed. More importantly, simulations have identified a new cage cavity configuration in which an SRF cage cavity’s quality factor is greater than 10exp10. The cage cavity must operate in a vacuum vessel which is also an RF cavity. By choosing the cage cavity resonant frequency to be decoupled from the vessel higher order resonances, simulations show that the cage cavity Q is ~95% of a solid wall SRF cavity. The Cage Cavity design, fabrication costs, and high order mode behavior have a number of advantages over solid wall cavities. However, the cage cavity also has limitations. The design and properties of the cage cavity will be discussed and compared with existing SRF cavities.

THP050	Development of Power Coupler for Superconducting Spoke Cavities for China ADS Proton Linac	cavity, coupling, simulation, Windows	1024
	X. Chen, T.M. Huang, H.Y. Lin, Q. Ma, F. Meng, W.M. Pan, Y.H. Peng IHEP, Beijing, People's Republic of China
	Abstract: The China-ADS proton linac adopts β=0.12 superconducting Spoke cavities. Each cavity is powered via a 325MHz coaxial power coupler. The coupler is to feed 6kW maximum power though it is designed to handle at 15kW .Two coupler sets have been made by IHEP so far, and a 10kW RF power in continuous travelling wave mode has passed through the coupler during high power test in late January 2013. An introduction of this coupler design and the room temperature test results are presented in this paper.

THP052	Cornell’s Beam Line Higher Order Mode Absorbers	HOM, linac, cryomodule, damping	1027
	R.G. Eichhorn, J.V. Conway, Y. He, Y. Li, T.I. O'Connel, P. Quigley, J. Sears, N.R.A. Valles Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA V.D. Shemelin Cornell University, Ithaca, New York, USA
	Efficient damping of the higher-order modes (HOMs) of the superconducting cavities is essential for the proposed energy recovery linac at Cornell that aims for high beam currents and short bunches. Designing these HOM beamline absorbers has been a long endeavor, sometimes including disappointing results. We will review the design, the findings on the prototype and the final choices made for the 7 HOM absorbers being built for the main linac cryomodule (MLC) prototype.

THP054	Last Spiral 2 Couplers Preparation and RF Conditioning	cryomodule, multipactoring, controls, cavity	1036
	Y. Gómez Martínez, M.A. Baylac, P. Boge, T. Cabanel, P. De Lamberterie, M. Marton, R. Micoud LPSC, Grenoble Cedex, France
	Six crymodules are ready to be installed in the SPIRAL 2 LINAC. We present here the protocols used for the preparation and for the RF conditioning of the couplers and the obtained results.

THP055	Ferrite Covered Ceramic Break HOM Damper	cavity, gun, HOM, damping	1040
	H. Hahn, S.A. Belomestnykh, I. Ben-Zvi, L.R. Hammons, V. Litvinenko, R.J. Todd, D. Weiss, W. Xu BNL, Upton, Long Island, New York, USA A. Burrill HZB, Berlin, Germany J. Dai Stony Brook University, Stony Brook, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under contract no. DE-AC02-98CH10886 with the DOE. The Brookhaven Energy Recovery Linac (ERL) is operated as R&D setup for high-current, high charge electron beams. It is comprised of a superconducting (SC) five-cell cavity and a half-cell SC photoinjector electron RF gun. Achieving the performance objectives requires effective HOM damping in the linac and gun cavity. Among the HOM dampers being developed is a beam-tube type HOM load for the electron gun consisting of a ceramic break surrounded by ferrite tiles. This design is innovative in its approach and achieves a variety of ends including broadband HOM damping and protection of the superconducting cavity from potential damage of the separately cooled ferrite tiles. The damper properties are described by the coupling impedance to a beam and the external Q to constrain the unloaded mode Q’s. Measured results for the gun damper at room and superconducting temperatures are presented

THP056	Validation Procedures for the IFMIF Power Coupler Prototypes	operation, controls, target, linac	1043
	H. Jenhani, P. Carbonnier, Y. Gasser, N. Grouas, P. Hardy, V.M. Hennion, F. Orsini, Y. Penichot, B. Renard, D. Roudier CEA/IRFU, Gif-sur-Yvette, France S.J. Einarson, T.A. Treado CPI, Beverley, Massachusetts, USA D. Regidor, M. Weber CIEMAT, Madrid, Spain
	In the framework of the International Fusion Materials Irradiation Facility (IFMIF), which consists of two high power CW accelerator drivers, each delivering a 125 mA deuteron beam at 40 MeV, a Linear IFMIF Prototype Accelerator (LIPAc) is presently under design for the first phase of the project. The first two IFMIF Power Coupler Prototypes were manufactured for LIPAc. Series of acceptance tests have been performed successfully. Prototype Power Couplers have been then cleaned and assembled in an ISO 5 cleanroom. A dedicated test bench allowing RF conditioning of the couplers up to 200 kW CW at 175 MHz was achieved. RF power conditioning is planned to start during October 2013.

THP065	Design of 352.21 MHz RF Power Input Coupler and Window for the European Spallation Source Project (ESS)	operation, cavity, multipactoring, SRF	1069
	E. Rampnoux, S. Bousson, S. Brault, P. Duchesne, P. Duthil, G. Olry, D. Reynet IPN, Orsay, France
	A 352.21 MHz RF high power coupler window was designed by IPNO to meet the specification requirements for the ESS accelerator project. This designed is based on IPNO’s power coupler developments performed in the framework of the EURISOL Design Study project for which two power couplers using coaxial technology without chokes systems around the ceramic disc have been designed and tested successfully up to 20 kW RF power level in CW mode. For ESS project, the RF power input window was developed and designed to reliability operate at an average power level of 25 kW up to 300 kW in pulsed and continuous wave modes. This 352.21 MHz RF window was developed to remove the chocks usually used and provided the following advantages: more reliability, less expensive to manufacture, better vacuum, easier cleaning, less secondary electron-multipacting with specificity to present a bandwidth close to 1 GHz.

THP067	Testing of Copper Plating Quality on ReA3 Coupler Bellows and Approach to Improved Plating for FRIB Production	SRF, experiment, cavity, controls	1077
	L. Popielarski, M. Goodrich, M. Hodek, I.M. Malloch, N.M. Nicholas, R. Oweiss, J. Popielarski, N. Putnam, K. Saito, D.R. Victory FRIB, East Lansing, Michigan, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. The SRF community faces difficulties finding repeatable, quality copper plating for fundamental power coupler (FPC) components. The copper plating of ten small custom bellows of β=0.085 Quarter-Wave Resonator (QWR) variable couplers for the ReAccelerator project has presented technical challenges. An improvement plan has been established and includes: better defining plating requirements and specification, creating testing processes to assure plating quality (Acceptance Criteria Listing (ACL)), identify viable plating vendors, develop clean, robust plating fixtures, procedures and quality assurance steps with multiple vendors, and perform ACL testing on plated bellows. A total of 24 prototype and production plated bellows are analyzed through acceptance testing, which include a vacuum leak check, tape test, 1000 psi water rinse, thermal cycle at 77K, borescope inspection and final leak check. Select bellows have been processed and tested with a quarter-wave resonator. A summary of the plating improvement program, plated bellows acceptance statistics, and RF test results will be reported.

THP072	Input Coupler for Cornell ERL Main Linac	linac, cavity, cryomodule, operation	1094
	V. Veshcherevich, P. Quigley Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Work is supported by the National Science Foundation grant DMR-0807731. Each cavity of the Cornell ERL Main Linac has a single coaxial type input coupler with fixed coupling, Qext = 6.5×E7. The input coupler will operate at RF power up to 5 kW at full reflection. The coupler design is based on the design of TTF-III input coupler with appropriate modifications and with taking into account the Cornell experience with couplers for ERL Injector. Seven couplers have been fabricated by CPI, Beverly and tested at Cornell on the test stand up to 5 kW CW. No major issues were noticed during the test. One coupler was attached to the prototype linac cavity. The cavity was successfully tested with great results achieved inside the horizontal test cryomodule. Six other couplers will be installed in the Main Linac Cryomodule (MLC) Prototype.

THP073	HOM Dampers and Waveguide for the Short Pulse X-Ray (SPX) Project	HOM, cavity, cryomodule, damping	1098
	G.J. Waldschmidt, B. Brajuskovic, D.J. Bromberek, J.D. Fuerst, J.P. Holzbauer, A. Nassiri, Y. Shiroyanagi, G. Wu ANL, Argonne, USA V.D. Shemelin Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357. The production of HOM dampers for the superconducting SPX cavities has been undertaken at the Advanced Photon Source. The dampers are vacuum compatible loads that utilize a four wedge design in WR284 rectangular waveguide. The rf lossy material consists of hexoloy silicon carbide (SiC) due to its suitable mechanical and electrical material properties. Issues regarding manufacturing consist of initial SiC material failure due to fabrication stresses as well as substandard soldering bonds of the SiC to the copper damper bodies. In addition, integration into the cryomodule consists of rf, thermal, and mechanical design considerations of the dampers and the waveguide transmission lines. An analysis of the manufacturing and integration issues and remedies are discussed further in this paper.

THP079	Improvement of the Pneumatic Frequency Tuner of the Superconducting Resonators at IUAC	controls, linac, cavity, feedback	1107
	A. Pandey, G.K. Chaudhari, R.N. Dutt, S. Ghosh, D. Kanjilal, J. Karmakar, D.S. Mathuria, P. Patra, A. Rai, A. Roy, B.K. Sahu, S.K. Saini IUAC, New Delhi, India
	The existing phase locking scheme of the quarter wave resonators used in superconducting linear accelerator of Inter University Accelerator Centre consists of a fast (electronic) and a slow time scale (pneumatic) control. Presently, helium gas operated mechanical tuners are being used to phase lock the resonators against the master oscillator frequency and different ion beams have been accelerated and delivered to conduct experiments. The present pneumatic frequency tuner has two limitations: (a) no proportional flow control in vacuum condition (b) large hysteresis problem in the proportional valve responsible for gas flow control. Due to these limitations, the system becomes non-linear and the response time is very slow (~sec). Using the existing system, phase locking of a resonator becomes delicate and time consuming. In addition, it was found to be difficult to implement auto phase locking mechanism on the resonator. To overcome these problems and to improve the dynamics of the existing tuner, a new pneumatic tuning system has been adopted. Details of the existing tuning mechanism and the modified tuning system along with the test results will be presented in the paper.

THP080	SRF Cavity Tuning for Low Beam Loading	cavity, resonance, operation, cryomodule	1110
	N. Solyak, E. Borissov, I.V. Gonin, C.J. Grimm, T.N. Khabiboulline, R.V. Pilipenko, Y.M. Pischalnikov, W. Schappert, V.P. Yakovlev Fermilab, Batavia, USA
	The design of 5-cell elliptical 650 MHz β=0.9 cavities to accelerate H⁻ beam of 1 mA average current in the range 467-3000 MeV for the Project X Linac is currently under development at Fermilab. The low beam current enables cavities to operate with high loaded Q’s and low bandwidth, making them very sensitive to microphonics. Mechanical vibrations and the Lorentz force can drive cavities off resonance during operation; therefore the proper design of the tuning system is very important part of cavity mechanical design. In this paper we review the design, performance, operation, reliability and cost of fast and slow tuners for 1.3 GHz elliptical cavities. We also present a design of the slow and fast tuners for 650 MHz β=0.9 cavities based on this experience. The HV in the new design is equipped with the tuners located at the end of the cavity instead of the initially proposed blade tuner located in the middle. We will present the results of ANSYS analyses of mechanical properties of tuners.

FRIOB02	Development and Performance of 325 MHz Single Spoke Resonators for Project X	cavity, operation, niobium, electron	1187
	L. Ristori, M.H. Awida, P. Berrutti, C.M. Ginsburg, I.V. Gonin, T.N. Khabiboulline, M. Merio, T.H. Nicol, D. Passarelli, A.M. Rowe, D.A. Sergatskov, A.I. Sukhanov, V.P. Yakovlev Fermilab, Batavia, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy. Two types of single spoke resonators will be utilized for beam-acceleration in the low energy part of the Project X linac. SSR1 and SSR2 operate at 325 MHz and at an optimal beta of 0.22 and 0.51 respectively. After the initial phase of prototyping, a production run of 10 SSR1 resonators was recently completed in US industry. The qualification of this group of resonators in the Fermilab VTS is proceeding successfully and nearly complete. The first qualified resonator has been outfitted with a Stainless Steel helium vessel. Preliminary test results for the first jacketed SSR1 are presented. The first RF power couplers were ordered, the design of the double-lever tuning mechanism is almost complete.
	Slides FRIOB02 [8.800 MB]

Paper

Title

Other Keywords

Page

MOIOA02

Status and Challenges of Spiral2 SRF Linac

cryomodule, linac, cavity, ion

11

R. Ferdinand, P.-E. Bernaudin, M. Di Giacomo
GANIL, Caen, France
P. Bosland
CEA/IRFU, Gif-sur-Yvette, France
Y. Gómez Martínez
LPSC, Grenoble Cedex, France
G. Olry
IPN, Orsay, France

GANIL is presently extending its experimental facility with the new SPIRAL2 project. It is based on a multi-beam Superconducting Linac Driver delivering 5 mA deuterons up to 40 MeV and 1 mA heavy ions up to 14.5 MeV/u. Several domains of research in nuclear physics at the limits of stability will be covered by this new accelerator. SPIRAL2 construction has two phases. SPIRAL2 phase 1 includes the superconducting accelerator driver, and the construction of the two research areas where the accelerated protons and deuterons will generate extremely intense neutron beams for fundamental physics experiments and numerous applications. SPIRAL2 will also accelerate stable heavy ion beams of very high intensity. The phase2 includes the RIB production building and links to the existing GANIL accelerator complex for RIB post acceleration. The Superconducting Linac incorporates many innovative developments of the Quarter-Wave resonators and their associated cryogenic and RF systems. The installation of the SPIRAL2 accelerator at GANIL has started. Status of the Spiral 2 SRF linac will be presented, focusing on the various SRF challenges met by this project and how/what solutions were chosen.
* on behalf of the SPIRAL2 project and superconducting teams

Slides MOIOA02 [87.841 MB]

MOP009

A Summary of the Advanced Photon Source (APS) Short Pulse X-ray (SPX) R&D Accomplishments

cavity, cryomodule, LLRF, laser

92

A. Nassiri, N.D. Arnold, T.G. Berenc, M. Borland, B. Brajuskovic, D.J. Bromberek, J. Carwardine, G. Decker, L. Emery, J.D. Fuerst, J.P. Holzbauer, D. Horan, J.A. Kaluzny, J.S. Kerby, F. Lenkszus, R.M. Lill, H. Ma, V. Sajaev, B.K. Stillwell, G.J. Waldschmidt, M. White, G. Wu, Y. Yang, A. Zholents
ANL, Argonne, USA
J.M. Byrd, L.R. Doolittle, G. Huang
LBNL, Berkeley, California, USA
P. Dhakal, J. Henry, J.D. Mammosser, J. Matalevich, R.A. Rimmer, H. Wang, K.M. Wilson
JLAB, Newport News, Virginia, USA
Z. Li, L. Xiao
SLAC, Menlo Park, California, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06H11357.
The Advanced Photon Source Upgrade Project (APS-U) at Argonne will include generation of short-pulse x-rays based on Zholents’ [1] deflecting cavity scheme. We have chosen superconducting (SC) cavities in order to have a continuous train of crabbed bunches and flexibility of operating modes. Since early 2012, in collaboration with Jefferson National Laboratory, we have made significant progress prototyping and testing a number of single-cell deflecting cavities. We have designed, prototyped, and tested silicon carbide as damping material for higher-order-mode (HOM) dampers, which are broadband to handle the HOM power across the frequency spectrum produced by the APS beam. In collaboration with Lawrence Berkeley National Laboratory, we have developing a state-of-the-art timing and synchronization system for distributing stable rf signals over optical fiber capable of achieving tens of femtoseconds phase drift and jitter. Collaboration with the Advanced Computations Department at Stanford Linear Accelerator Center is looking into simulations of complex, multi- cavity geometries. This contribution provides a progress report on the current R&D status of the SPX project.
[1] A. Zholents et al., NIM A 425, 385 (1999).

MOP014

Cold Tests of SSR1 Resonators for PXIE

cavity, radiation, cryomodule, SRF

112

A.I. Sukhanov, M.H. Awida, P. Berrutti, C.M. Ginsburg, T.N. Khabiboulline, O.S. Melnychuk, R.V. Pilipenko, Y.M. Pischalnikov, L. Ristori, A.M. Rowe, D.A. Sergatskov, V.P. Yakovlev
Fermilab, Batavia, USA

Fermilab is currently building the Project X Injector experiment (PXIE). PXIE linac will accelerate 1 mA H⁻ beam up to 30 MeV and serve as a testbed for validation of Project X concepts and mitigation of technical risks. A cryomodule of eight superconducting RF Single Spoke Resonators of type 1 (SSR1) cavities operating at 325 MHz is an integral part of PXIE. Ten SSR1 cavities were manufactured in industry and delivered to Fermilab. In this paper we discuss surface processing and tests of bare SSR1 cavities at the Fermilab Vertical Test Stand (VTS). We report on the measured performance parameters of nine cavities achieved during tests.

MOP030

Post-Production Dimensional Control of the Cold Masses and Vacuum Vessels for the XFEL Cryomodules

controls, alignment, cryomodule, site

165

S. Barbanotti, W. Benecke, K. Jensch, M. Noak, M. Schlösser
DESY, Hamburg, Germany

The very tight alignment tolerances required in the XFEL Linac reflect in very tight tolerances for the production of the main cryomodule components. To verify the adherence to the specified tolerances of the cold masses and vacuum vessels, dimensional controls with laser tracker are performed at the production site following DESY experts’ instructions and verified at DESY with an independent measurement. We present here the measurement strategy and a summary of the results obtained so far.

MOP031

Quality Control of the Vessel and Cold Mass Production for the 1.3 GHz XFEL Cryomodules

controls, cryomodule, operation, cavity

168

S. Barbanotti, H. Hintz, K. Jensch, W. Maschmann
DESY, Hamburg, Germany

The industrial production of one hundred cold masses and vacuum vessels for the 1.3 GHz XFEL cryomodules is now fully in operation. Quality checks at the companies and controls at DESY assure the quality level required for the cryomodule assembly. Verification of the main production steps, non-destructive tests, dimensional controls are performed by DESY personnel before accepting the components. This paper resumes the quality control strategy and the results for the first components produced by the companies.

MOP036

New Technique and Result of Laser Welded SCRF Cavity Developed at RRCAT

cavity, laser, niobium, experiment

186

P. Khare, R. Arya, J. Dwivedi, R. Ghosh, G. Gilankar, C. Gupta, P.D. Gupta, A. Jain, S.C. Joshi, G.V. Kane, R. Kaul, P.K. Kush, G. Mundra, S.M. Oak, C.K. Pithawa, P. Ram Sankar, S.B. Roy, V.C. Sahni, R.S. Sandha, P. Shrivastava, B.N. Upadhyay
RRCAT, Indore (M.P.), India
C.A. Cooper, C.M. Ginsburg, A. Grassellino, C.S. Mishra, A.M. Rowe
Fermilab, Batavia, USA

A new technique to fabricate SCRF cavities with the help of laser welding process has been developed at Raja Ramanna Centre for Advanced Technology RRCAT), Indore, Department of Atomic Energy, India. In this technique, a pulsed Nd:YAG laser has been used and welding was performed in inert gas environment, in a specially designed welding rig. The advantages of this technique are reduced cost, small heat affected zone, no necessity to weld in vacuum and enhanced rate of production. The paper describes the technique and fabrication method of a single-cell 1.3 GHz SCRF cavity which was fabricated at RRCAT with this new technique. It also discusses the test result of this cavity which was processed and tested at Fermilab. The cavity reached an Eacc of 17MV/m with a Q0 of 1.4 E +10 at 2K. The cavity is being barrel polished for further improvement.

MOP037

Test of the 1.3 GHz Superconducting Cavities for the European X-ray Free Electron Laser

cavity, HOM, software, pick-up

191

K. Krzysik
DESY, Hamburg, Germany
B. Dzieza, W. Gaj, D. Karolczyk, K. Kasprzak, L.M. Kolwicz-Chodak, A. Kotarba, A. Krawczyk, W. Maciocha, A. Marendziak, K. Myalski, S. Myalski, T. Ostrowicz, B. Prochal, M. Sienkiewicz, M. Skiba, J. Świerbleski, M. Wiencek, J. Zbroja, A. Zwozniak
IFJ-PAN, Kraków, Poland

The European X-ray Free Electron Laser (XFEL) is currently under construction in Germany in Hamburg area. A linear accelerating part of the XFEL is going to consist of 808 superconducting 9-cell Niobium cavities installed in 101 accelerating modules. Before assembly into modules the cavities are tested in a dedicated test facilities. The testing procedures are prepared based on DESY expertise and available software from Tesla Test Facility (TTF) Collaboration and Free electron LASer for Hamburg (FLASH). RF test provides the most important information about cavity performance: maximum available gradient and dependence of quality factor and radiation on the gradient. Results of the RF test determine, whether a cavity is shipped to CEA Saclay (France) to be assembled into a module or send for retreatment to improve its performance. In this paper we present the most important aspects of the cavity RF test procedure.

MOP040

Industrialization of European XFEL Preparation Cycle “Final EP ” at Research Instruments Company

cavity, controls, acceleration, radiation

201

A. Matheisen, N. Krupka, M. Schalwat, A. Schmidt, M. Schmökel, W. Singer, B. van der Horst
DESY, Hamburg, Germany
P. Michelato, L. Monaco
INFN/LASA, Segrate (MI), Italy
M. Pekeler
RI Research Instruments GmbH, Bergisch Gladbach, Germany

In the Specification for XFEL Cavity preparation (R1) two different preparation sequences are presented. Research Instruments Company as one of the two companies contracted for XFEL cavity production and preparation has chosen the so called “final EP” cycle. Major infrastructure components like EP facility and the BCP facility were pre- qualified. This existing and the new set up areas like the cleanroom are distributed over the ground area of the industrial park Bergisch Gladbach. The process flow given in the DESY specification needed adaptation to this scenario. Additional infrastructure beside the once specified needed to be set up to ensure the same quality of processes even with a changed work flow. The general lay out of the facility, matched work flow of preparation and test results of resonators processed by RI company in their infrastructure will be reported.
(R1) Series Surface and acceptance test preparation of superconducting cavities for the European Xfel (XFEL/A - D) JUNE 30, 2009

MOP042

Quality Control and Processes Optimization for the EXFEL Superconducting Cavities Series Production at Ettore Zanon spa

cavity, controls, operation, SRF

208

L. Facci, D. Rizzetto
Ettore Zanon S.p.A., Nuclear Division, Schio, Italy
G. Corniani
Ettore Zanon S.p.A., Schio, Italy
A. Matheisen
DESY, Hamburg, Germany
P. Michelato, L. Monaco
INFN/LASA, Segrate (MI), Italy

The construction of the European XFEL forced the first mass production of Niobium bulk SRF cavities. In this context Ettore Zanon S.p.A. built a fully new facility designed to produce four fully treated and He tank equipped cavities per week, ready to be tested at DESY. The facility already reached the foreseen production rate. The guarantee of the highest quality of the resonators produced requires a very strict quality control plan. At the same time, the requirements of the industrial production in terms of time, cost and productivity must be satisfied. As a consequence processes must be standardized and working times optimized. In the following, after the description of the production facility, we would like to highlight and discuss the strategies and arrangements adopted in the various critical fields (clean room, vacuum, etc.) to ensure the foreseen results. Moreover correlation between cavities performances and production cycle parameters will be investigated and discussed.

MOP044

Performance Characteristics of Jefferson Lab’s New SRF Infrastructure

SRF, cavity, cryomodule, cryogenics

216

C.E. Reece, P. Denny, A.V. Reilly
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
In the past two years, Jefferson Lab has reconfigured and renovated its SRF support infrastructure as part of the Technology and Engineering Development Facility project, TEDF. The most significant changes are in the cleanroom and chemistry facilities. We report the initial characterization data on the new ultra-pure water systems, cleanroom facilities, describe the reconfiguration of existing facilities and also opportunities for flexible growth presented by the new arrangement.

MOP047

Set up of Production Line for EXFEL Beam Position Monitor and Quadrupol Units for Cavity String Assembly at CEA

alignment, controls, quadrupole, status

224

M. Schalwat, M. Koepke, A. Matheisen, H. Weitkämper
DESY, Hamburg, Germany

The super conducting (s.c.) accelerator models of the EXFEL consist of eight s.c. resonators, one s.c. quadrupol magnet and one beam position monitor. These components are connected inside ISO 4 cleanroom at CEA Saclay to a so called cavity string under the guidance of the XFEL WP 09 activities. The eight s.c. cavities are handed from DESY to CEA for string assembly after successful RF test. The beam- position monitor and Quadrupol units (BQU) are assembled and cleaned in the DESY cleanroom at DESY Hamburg to the same standard’s of cleanliness as requested for s.c. Cavities. The completed BQU units are handed over to CEA IRFU / WP 9 in “ready for installation to cavity string“ status. The setup of infrastructure, the qualification of processes and transport as well as the ramp up to a delivery rate of 1 BQU per week will be presented.

MOP051

The Statistics of Industrial XFEL Cavities Fabrication at Research Instruments

cavity, target, controls, status

234

A.A. Sulimov, J.H. Thie
DESY, Hamburg, Germany
M. Pekeler, D. Trompetter
RI Research Instruments GmbH, Bergisch Gladbach, Germany

Serial production of superconducting cavities for European-XFEL was successfully started at Research Instrument (RI) at the end of last year. The production rate (3-4 cavities a week) allows us to summarize the results and present the statistics of industrial cavity fabrication. Many parameters have been traced during different steps of cavity production. The most interesting of them, as cavity length, frequency, field flatness and eccentricity, are presented and discussed.

Poster MOP051 [0.769 MB]

MOP057

Developments and Tests of a 700 MHz Cryomodule for the Superconducting Linac of MYRRHA

cavity, cryomodule, linac, cryogenics

250

F. Bouly
CERN, Geneva, Switzerland
S. Berthelot, J.-L. Biarrotte, M. El Yakoubi, C. Joly, J. Lesrel, E. Rampnoux
IPN, Orsay, France
A. Bosotti, R. Paparella, P. Pierini
INFN/LASA, Segrate (MI), Italy

Funding: This work is being supported by the European Atomic Energy Community’s EURATOM) Seventh Framework Programme under grant agreement n°269565(MAX project).
The MYRRHA (“Multi-purpose Hybrid Research reactor for High-tech Applications”) project aims at the construction of a new flexible fast spectrum research reactor. This reactor will operate as an Accelerator Driven System demonstrator. The criticality will be sustained by an external spallation neutron flux; produced thanks to a 600 MeV high intensity proton beam. This CW beam will be delivered by a superconducting linac which must fulfil very stringent reliability requirements. In this purpose, the accelerator design is based on a redundant and fault-tolerant scheme to enable the rapid mitigation of RF failures. To carry out “real scale” reliability-oriented experiments a prototype of cryomodule was developed by INFN Milano and installed at IPN Orsay. The module holds a 700 MHz 5-cell elliptical cavity (βg = 0.47) equipped with its blade frequency tuner. Several tests were carried out to commission the experimental set-up. We review here the obtained results and the lessons learnt by operating this module, as well as the on-going developments.

MOP059

Management for the Long-Term Reliability of the Diamond Superconducting RF Cavities

cavity, SRF, ion, electron

255

P. Gu, C. Christou, M.P. Cox, S.A. Pande, A.F. Rankin, H.S. Shiers, A.V. Watkins
Diamond, Oxfordshire, United Kingdom

Diamond started operation with users in January 2007 and the Diamond storage ring superconducting RF cavities used to be the largest single contributor to unplanned beam trips. Extensive effort has been dedicated to understand and improve the long-term stability of the SRF cavities. Our experience shows that the long-term stability of superconducting RF cavities relies heavily on the surface conditions. Gases keep accumulating on the cold surfaces with time due to its huge cryo-pumping capacity. The integral effect will ultimately lead to fast vacuum trips during operation. In Diamond, we have developed a systematic approach to control the long-term stability of the SRF cavities. We will discuss here our approach and also present the future work that should be completed.

MOP062

Production of 500 MHz SRF Modules the KEKB-type for Taiwan Photon Source

SRF, cavity, niobium, operation

263

Ch. Wang, L.-H. Chang, M.H. Chang, L.J. Chen, F.-T. Chung, M.-C. Lin, Y.-H. Lin, Z.K. Liu, C.H. Lo, M.H. Tsai, T.-T. Yang, M.-S. Yeh, T.-C. Yu
NSRRC, Hsinchu, Taiwan
T. Furuya, K. Hara, T. Honma, A. Kabe, Y. Kojima, S. Mitsunobu, Y. Morita, H. Nakai, K. Nakanishi, M. Nishiwaki, S. Takano
KEK, Ibaraki, Japan
F. Inoue, K. Sennyu, T. Yanagisawa
MHI, Hiroshima, Japan

The KEKB-type single-cell 500-MHz superconducting radio frequency (SRF) modules have been selected to power the 3 GeV, 500 mA, storage ring of the constructing Taiwan Photon Source (TPS) at National Synchrotron Radiation Research Center (NSRRC). The design target is to routinely deliver RF forward power up to 300 kW, CW, to single SRF module with highly reliable operation. Three sets of SRF modules have been successfully produced under a tight collaboration with High Energy Accelerator Research Organization (KEK) and Mitsubishi Heavy Industries Ltd. (MHI), after obtaining the technology transfer from KEK. MHI is responsible for the mechanical fabrication and cryo-module assembly, KEK for the surface and RF treatments of the niobium cavities, high power input couplers and HOM dampers and for the liquid-helium tests of the cryo-modules, and NSRRC for the electronic/diagnostic system, final assembly and system integration, high power horizontal test, and reliable test. This work reports the results obtained during the production of these three SRF modules at KEK and NSRRC.

MOP063

Mature Operation of CESR-Type 500-MHz SRF Module at Taiwan Light Source

SRF, operation, cavity, cryogenics

266

Ch. Wang, L.-H. Chang, M.H. Chang, L.J. Chen, F.-T. Chung, M.-C. Lin, Y.-H. Lin, Z.K. Liu, C.H. Lo, M.H. Tsai, T.-T. Yang, M.-S. Yeh, T.-C. Yu
NSRRC, Hsinchu, Taiwan

The Cornell-type 500-MHz SRF module has been routinely operated since the end of 2004 to power the 1.5 GeV Taiwan Light Source with 360 mA in top-up mode. A new record of SRF operation with mean time between failures (MTBF)up to 800 hr has been achieved in the 1st half of 2013 that is compatible with the best operational record of room temperature cavities ever made in the same machine. To meet the user’s strict requirements on highly operational reliability, developing in advanced diagnostic instrumentation together with user-friendly event logging software does never stop. Here, we review our SRF operational experience in last 9 years.

MOP064

Operational Experience with the SOLEIL Superconducting RF System

cavity, cryogenics, operation, HOM

269

P. Marchand, J.P. Baete, R.C. Cuoq, H.D. Dias, M. Diop, J.L. Labelle, R. Lopes, M. Louvet, C.M. Monnot, S. Petit, F. Ribeiro, T. Ruan, R. Sreedharan, K. Tavakoli
SOLEIL, Gif-sur-Yvette, France

In the SOLEIL storage ring, two cryomodules provide to the electron beam an accelerating voltage of 3-4 MV and a power of 575 kW at 352 MHz. Each cryomodule contains a pair of superconducting cavities, cooled with liquid Helium at 4K, which is supplied by a single 350 W cryogenic plant. The RF power is provided by 4 solid state amplifiers, each delivering up to 180 kW. The parasitic impedances of the high order modes are strongly mitigated by means of four coaxial couplers, located on the central pipe connecting the two cavities. Seven years of operational experience with this system as well as its upgrades are reported.

MOP067

Results From Initial Tests of the 1st Production Prototype β=0.29 and β=0.53 HWR Cavities for FRIB

cavity, linac, target, cryomodule

280

J.P. Ozelis, C. Compton, K. Elliott, M. Hodek, M. Leitner, I.M. Malloch, D. Miller, S.J. Miller, D. Norton, R. Oweiss, J. Popielarski, L. Popielarski, A.P. Rauch, K. Saito, G.J. Velianoff, D.R. Victory
FRIB, East Lansing, USA

Funding: Work supported by US DOE Cooperative Agreement DE-SC0000661 and Michigan State University
The first prototypes of the β=0.53 and β=0.29 HWR production design cavities for FRIB were fabricated early this year by Roark Manufacturing Company and delivered to MSU. These cavities have undergone an extensive evaluation program to verify both mechanical and RF performance before proceeding with fabrication of a pre-production run of 10 cavities. Results from physical inspections, warm RF measurements, chemical processing, and cryogenic vertical testing will be presented.

MOP073

IHEP 1.3 GHz Low Loss Large Grain 9-cell Cavity Fabrication, Processing and Test

cavity, HOM, SRF, niobium

305

J.Y. Zhai, J. Gao, S. Jin, Z.Q. Li, Y. Liu, Z.C. Liu, Z.H. Mi, X.H. Peng, T.X. Zhao, H.J. Zheng
IHEP, Beijing, People's Republic of China
C.A. Cooper, C.M. Ginsburg, T.N. Khabiboulline, A.M. Rowe, D.A. Sergatskov
Fermilab, Batavia, USA
J.X. Wang, H. Yu, H. Yuan
BIAM, Beijing, People's Republic of China

The combination of the low-loss shape and large grain niobium material is expected to be the possible way to achieve higher gradient and lower cost for ILC 9-cell cavities, and will be essential for the ILC 1 TeV upgrade. As the key component of the “IHEP 1.3 GHz SRF Accelerating Unit Project”, a low-loss shape 9-cell cavity with full end groups using Ningxia large grain niobium (IHEP-02) was fabricated at IHEP in 2012. The cavity was processed (CBP and EP) and tested at FNAL. The cavity processing,test performance and gradient limitation is reported in this paper. We will weld the helium vessel, assemble the magnetic shield and install the cavity to IHEP ILC-TC1 cryomodule.

MOP074

Design and Construction of the Main Linac Cryomodule for the Energy Recovery Linac Project at Cornell

linac, cryomodule, alignment, cryogenics

308

R.G. Eichhorn, B. Bullock, J.V. Conway, Y. He, T.I. O'Connel, P. Quigley, D.M. Sabol, J. Sears, E.N. Smith, V. Veshcherevich
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Cornell University has been designing and building superconducting accelerators for various applications for more than 50 years. Currently, an energy-recovery linac (ERL) based synchrotron-light facility is proposed making use of the existing CESR facility. As part of the phase 1 R&D program funded by the NSF, critical challenges in the design were addressed, one of them being a full linac cryo-module. It houses 6 superconducting cavities- operated at 1.8 K in continuous wave (CW) mode - with individual HOM absorbers and one magnet/ BPM section. Pushing the limits, a high quality factor of the cavities and high beam currents (2*100 mA)are targeted. We will present the design of the main linac module (MLC) being finalized recently, its cryogenic features and report on the status of the fabrication which started in late 2012

MOP077

Cryomodule Component Development for the APS Upgrade Short Pulse X-Ray Project

cavity, cryomodule, HOM, alignment

314

J.P. Holzbauer, J.D. Fuerst, A. Nassiri, Y. Shiroyanagi, B.K. Stillwell, G.J. Waldschmidt, G. Wu
ANL, Argonne, USA
G. Cheng, J. Henry, J.D. Mammosser, J. Matalevich, J.P. Preble, R.A. Rimmer, H. Wang, K.M. Wilson, M. Wiseman, S. Yang
JLAB, Newport News, Virginia, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CHI1357 at ANL and under U.S. DOE Contract No. DE-AC05-06OR23177 at Jefferson Lab.
The short pulse x-ray (SPX) part of the Advanced Photon Source Upgrade calls for the installation of a two-cavity cryomodule in the APS ring to study cavity-beam interaction, including HOM damping and cavity timing and synchronization. Design of this cryomodule is underway at Jefferson Lab in collaboration with the APS Upgrade team at ANL. The cryomodule design faces several challenges including tight spacing to fit in the APS ring, a complex set of cavity waveguides including HOM waveguides and dampers enclosed in the insulating vacuum space, and tight alignment tolerances due to the APS high beam-current (up to 150 mA). Given these constraints, special focus has been put on modifying existing CEBAF-style designs, including a cavity tuner and alignment scheme, to accommodate these challenges. The thermal design has also required extensive work including coupled thermal-mechanical simulations to determine the effects of cool-down on both alignment and waveguides. This work will be presented and discussed in this paper.

MOP078

Horizontal Testing of a Dressed Deflecting Mode Cavity for the APS Upgrade Short Pulse X-Ray Project

cavity, controls, operation, photon

321

J.P. Holzbauer, N.D. Arnold, T.G. Berenc, D.J. Bromberek, J. Carwardine, N.P. Di Monte, J.D. Fuerst, A.E. Grelick, D. Horan, J.A. Kaluzny, J.W. Lang, H. Ma, T.L. Mann, D.A. Meyer, M.E. Middendorf, A. Nassiri, Y. Shiroyanagi, J.H. Vacca, G.J. Waldschmidt, R.D. Wright, G. Wu, Y. Yang, A. Zholents
ANL, Argonne, USA
E.R. Harms, W. Schappert
Fermilab, Batavia, USA
J.D. Mammosser
JLAB, Newport News, Virginia, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CHI1357.
The short pulse x-ray (SPX) part of the Advanced Photon Source (APS) Upgrade is an effort to enhance time-resolved experiments on a few-ps-scale at the APS. The goal of SPX is the generation of short pulses of x-rays for pump-probe time-resolved capability using superconducting rf (SRF) deflecting cavities*. These cavities will create a correlation between longitudinal position in the electron bunch and vertical momentum**. The light produced by this bunch can be passed through a slit to produce a pulse of light much shorter (1-2 ps instead of 100 ps) than the bunch length at reduced flux. An SPX cavity has been tested with a helium vessel and tuner. In addition to studying rf performance with more realistic cooling, this test allowed integration and operation of many systems designed for SPX cryomodule in-ring operation. These systems included an APS-constructed 5 kW, 2.815 GHz amplifier, a digital low-level rf controller system designed and fabricated in collaboration with LBNL, a cavity tuner, and instrumentation systems designed for the existing APS infrastructure. Cavity performance and subsystem performance will be reported and discussed in this paper.
* A. Zholents et al., NIM A 425, 385 (1999).
** A. Nassiri et al., “Status of the Short-Pulse X-Ray Project at the Advanced Photon Source,” IPAC 2012, New Orleans, LA, May 2012.

MOP079

Design and Test of a Cryogenic Seal for Rectangular Waveguide Using VATSEAL Technology

cryogenics, superconducting-RF, detector, controls

325

J.D. Fuerst, J.P. Holzbauer, J.A. Kaluzny, C.R. Montiel, Y. Shiroyanagi, B.K. Stillwell
ANL, Argonne, USA

Funding: This work was supported by the U. S. Department of Energy, Office of Science, under contract No. DE-AC02-06CH11357.
A commercially available rectangular metal seal from VAT Vacuum Valves AG has been evaluated and cold tested as a possible cryogenic seal for srf cavities. A program of analysis and cryogenic testing was undertaken to evaluate seal parameters and suitability. Seal line loads, bolt torque and resultant flange/seal deformation at low temperature and during thermal cycling were calculated both statically and via time-dependent numerical simulation to confirm the mechanical integrity of the flange/seal system. Cold testing of flange/waveguide assemblies included thermal shocks in liquid nitrogen and realistic cool-downs below the λ point. Acceptable seal performance has been demonstrated under all test conditions although seal joint assembly is sensitive to details including bolt torque, flange flatness, and surface finish.

MOP080

Design of a New Horizontal Test Cryostat for SCRF Cavities at the Uppsala University

cavity, cryomodule, radiation, operation

328

T. Junquera, P. Bujard, N.R. Chevalier, J.P. Thermeau
Accelerators and Cryogenic Systems, Orsay, France
L. Hermansson, M. Noor, R.J.M.Y. Ruber, R. Santiago Kern
Uppsala University, Uppsala, Sweden
H. Saugnac
IPN, Orsay, France

At Uppsala University, the FREIA facility for research and development of new accelerators and associated instrumentation, is presently in construction. Associated to a new Helium Liquefier, a Horizontal Test Cryostat will be used for high power RF tests of completely equipped SC cavities. This paper presents the main characteristics of the cryostat and the associated cryogenic distribution system. Two types of cavities have been considered for test purpose: SC elliptical cavities for future free electron lasers and SC cavities for high intensity proton accelerators (i.e. SC spokes). A special valve box including a subcooling stage and power coupler cooling with supercritical Helium supply have been designed, for temperature operation ranging from 2K to 4.2 K. This facility will play an essential role in the development and test of cavities, couplers and cryomodules for the ESS project. High power RF sources will be installed in order to allow unique and complete tests of spoke cavities and cryomodules at high nominal peak power.

MOP082

Development and Test of a New Cryostat Module for the Injector of the S-DALINAC*

electron, operation, cavity, linac

334

T. Kürzeder, J. Conrad, F. Hug, N. Pietralla, A. Richter, S.T. Sievers
TU Darmstadt, Darmstadt, Germany
R.G. Eichhorn
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: *This work is supported by the DFG through the Collaborative Research Center SFB 634.
The present injector of the superconducting Darmstadt electron linear accelerator S-DALINAC provides an electron beam of up to 10 MeV kinetic energy and up to 60 μA current in continuous wave operation. A new cryostat module has been constructed to replace the actual one in order to provide higher beam energies of up to 14 MeV and currents of up to 250 μA for nuclear resonance fluorescence experiments at the Darmstadt High Intensity Photon Setup (DHIPS). As before two 20-cell superconducting microwave cavities will be operated at an acceleration frequency of 3 GHz in a liquid helium bath at 2 K. For the injector upgrade two new elliptical 20-cell niobium cavities were also manufactured and in addition a third spare one. The rf power is transferred to the cavities by an also newly developed waveguide-transition line and input couplers. We report on the construction of the cryostat module and its components and present the results of a first cooling-down procedure.

MOP084

ESS Cryomodules for Elliptical Cavities

cryomodule, cryogenics, cavity, operation

341

G. Olivier, J.P. Thermeau
IPN, Orsay, France
P. Bosland
CEA/IRFU, Gif-sur-Yvette, France
C. Darve
ESS, Lund, Sweden

The European Spallation Source will be the world's most powerfull neutron source. IPN Orsay undertakes the development of the ESS linac cryomodules for both medium and high beta elliptical cavities which constitute the high energy section. A medium beta technical demonstrator will be built in a first time. The cryomodules are composed of 4 superconducting cavities cooled at 2K. The cold mass assembly is hanged in an intermediate structure located inside the vacuum vessel. A 50K fixed temperature is implemented by the mean of an aluminium shield. Each cryomodule is connected to the cryogenic distribution line. The vacuum vessel is 6.3m long and has a 1.2m diameter. The poster describes the general design,the solutions implemented, the characteristics of the main components and the mechanical/thermal calculations .

MOP085

Status of the Superconducting Proton Linac (SPL) Cryomodule

cavity, cryogenics, operation, linac

345

V. Parma, R. Bonomi, O. Capatina, J.K. Chambrillon, E. Montesinos, K.M. Schirm, A. Vande Craen, G. Vandoni, R. van Weelderen
CERN, Geneva, Switzerland
G. Devanz
CEA/IRFU, Gif-sur-Yvette, France
P. Duchesne, P. Duthil, S. Rousselot
IPN, Orsay, France

The Superconducting Proton Linac (SPL) is an R&D effort conducted by CERN in partnership with other international laboratories, aimed at developing key technologies for the construction of a multi-megawatt proton linac based on state-of-the-art SRF technology. Such an accelerator would serve as a driver in new physics facilities for neutrinos and/or radioactive ion beams. Amongst the main objectives of this effort, are the development of 704 MHz bulk niobium β=1 elliptical cavities (operating at 2 K and providing an accelerating field of 25 MV/m) and the test of a string of cavities integrated in a machine-type cryo-module. In an initial phase, only four out of the eight cavities of the SPL cryo-module will be tested in a half- length cryo-module developed for this purpose, which nonetheless preserves the main features of the full size machine. This paper presents the final design of the cryo-module and the status of the construction of the main cryostat parts. Preliminary plans for the assembly and testing of the cryo-module at CERN are presented and discussed.

MOP089

Design of the ESS Spoke Cryomodule

cryomodule, cavity, operation, cryogenics

357

D. Reynet, S. Bousson, S. Brault, P. Duchesne, P. Duthil, N. Gandolfo, G. Olry, E. Rampnoux
IPN, Orsay, France

The European Spallation Source (ESS) project brings together 17 European countries to develop the world’s most powerful neutron source feeding multidisplinary researches. The superconducting part of the linear accelerator consists in 59 cryomodules housing different superconducting radiofrequency (SRF) resonators among which 28 paired β=0.5 352.2 MHz SRF niobium double Spoke cavities, held at 2K in a saturated helium bath. A prototype Spoke cryomodule with two cavities equipped with their 300kW RF power couplers is now being designed and will be constructed and tested at full power by the end of 2015 for the validation of all chosen technical solutions. It integrates all the interfaces necessary to be operational within a linac machine. Its assembly requires dedicated tooling and procedures in and out of a clean room. The design takes into account an industrial approach for the management of the fabrication costs. This prototype will have to guarantee an accelerating field of 8MV/m while optimizing the energy consumption and will aim at assessing the maintenance operations issues. We propose to present the design of this cryomodule and its related tooling.

TUIOC05

Purification of 6 GHz Cavities by Induction Heating

cavity, induction, niobium, SRF

419

A.A. Rossi, A. Battistello, M. Checchin, V. Palmieri, S. Stark, F. Stivanello, R.K. Thakur, G. Yu
INFN/LNL, Legnaro (PD), Italy

We have developed an innovative technique for purification of bulk-Nb 6GHz RF cavities under ultra-high vacuum (UHV) system. The main advantages of 6 GHz bulk-Nb cavities are saving cost, materials and time to collect statistics of surface treatments and RF test. Cavities are RF tested before and after high temperature treatment under UHV conditions. Induction heating method is used to anneal the cavity at temperatures higher than 2000°C and close to the melting point of Nb for less than a minute while few seconds at maximum temperature. Before RF test and UHV annealing, the surface treatment processes like tumbling, chemical, electro-chemical (such as BCP and EP), ultrasonic cleaning and high pressure rinsing (HPR) have been employed. This kind of Nb 6 GHz cavity purification allow to reduce hydrogen, oxygen and other elemental impurities content, which effects on cavity Q-factor degradation, by a rapid annealing over 2000°C and a subsequent rapid reduction at room temperature.

Slides TUIOC05 [42.171 MB]

TUP007

Vortex Penetration Field in the Multilayered Coating Model

cavity, superconductivity, electromagnetic-fields

430

T. Kubo, T. Saeki
KEK, Ibaraki, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan

A multilayered structure with a single superconductor layer and a single insulator layer deposited on a bulk superconductor is studied. General formulae for the vortex penetration-field of the superconductor layer and the magnetic field on the bulk superconductor which is shielded by the superconductor and insulator layers are derived with a rigorous calculation of the magnetic field attenuation in the multilayered structure. The formulae depend not only on the material and the thickness of the superconductor layer but also on the thickness of the insulator layer. The results can be applied to superconducting accelerating cavities with the multilayered structure. Using the formulae, a combination of the thicknesses of superconductor and insulator layers to enhance the RF breakdown field limits can be found for any given materials. (Submitted on 25 Apr 2013)
T. Kubo, Y. Iwashita and T. Saeki, arXiv:1304.6876 [physics.acc-ph](Submitted on 25 Apr 2013); arXiv:1306.4823 [physics.acc-ph](Proc. of IPAC13); arXiv:1307.0583 [physics.acc-ph](Proc. of SRF2013)

TUP014

Fast Table Top Niobium Hydride Investigations Using Direct Imaging in a Cryo-Stage

niobium, cavity, cryogenics, laser

447

F.L. Barkov, A. Grassellino, A. Romanenko
Fermilab, Batavia, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
Performance of niobium SRF cavities can be strongly affected by hydrogen segregation into lossy niobium hydrides as known for "hydrogen Q disease" at higher concentration of dissolved H and may be a reason for the "high field Q slope" at lower concentrations. With the use of optical cryostat and laser confocal microscope we have developed a "table top technique" for direct observation of hydride precipitation, and studied formation, morphology, and time evolution of hydrides after different treatments used for cavities. Our results show that hydrides can form at the niobium surface at 90-180K depending mainly on H concentration and the cooldown rate. A lot of H is absorbed by bulk niobium during mechanical polishing, which leads to the formation of very large (>10 microns) hydrides. Both EP and BCP do not influence H concentration significantly provided that temperature during treatments is kept below 15C. 800C degassing reduces H concentration and precludes large hydride precipitation. 120C baking and mechanical deformation do not change H concentration but affect hydride precipitation through their influence on the number of nucleation centers and H binding defects.

TUP029

Heat Treatment of SRF Cavities in a Low-Pressure Atmosphere

cavity, SRF, niobium, resonance

487

D. Gonnella, F. Furuta, M. Liepe
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: NSF
Recent results from FNAL on baking superconducting RF cavities at high temperatures in a low-pressure atmosphere of a few mTorr indicate that such treatments can increase the medium field quality factor. In this paper we report on studies from Cornell, giving new insight into the mechanism behind this effect.

TUP043

Nanostructural TEM/STEM Studies of Hot and Cold Spots in SRF Cavities

niobium, cavity, electron, SRF

504

Y. Trenikhina, J. Zasadzinski
IIT, Chicago, USA
A. Romanenko
Fermilab, Batavia, USA

Direct TEM/STEM imaging and spectroscopic chemical characterization by EELS/EDS of the surface of the SRF cavity cutouts before and after the treatments (e.g. in situ mild vacuum bake and rinsing with hydrofluoric acid) down to subnanometer scale is implemented to correspond the changes in niobium surface to the SRF performance of the cavities. We also report current results of the direct search, using cryogenic TEM stage, for suggested phase transformations in the niobium-hydrogen system* on “hot” and “cold” spot cavity cutouts, which may help clarifying the mechanism of the high field Q slope and its empirical cure.
*A. Romanenko, F. Barkov, L. D. Cooley, A. Grassellino, Supercond. Sci. Technol. 26 (2013) 035003.

TUP048

Preparations and VT Results of ERL7-cell at Cornell

cavity, cryomodule, target, radiation

521

F. Furuta, B. Bullock, R.G. Eichhorn, B. Elmore, A. Ganshin, G.M. Ge, G.H. Hoffstaetter, J.J. Kaufman, M. Liepe, J. Sears
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

We have fabricated 7 ERL 7-cell cavities for Cornell ERL project. 4 nu-stiffened and 3-stiffened cavities have been fabricated in house so far. Specification values of our 7-cell is 16.2MV/m with Qo of 2.0·10¹⁰ at 1.8K. In this report, we will describe our surface treatments recipe which is based on BCP and the results of vertical tests of these 7-cell cavities.

TUP051

Horizontal High Pressure Water Rinsing for Performance Recovery

cavity, cryomodule, operation, factory

527

Y. Morita, K. Akai, T. Furuya, A. Kabe, S. Mitsunobu, M. Nishiwaki
KEK, Ibaraki, Japan

Eight superconducting accelerating cavities were operated for more than ten years at the KEKB machine. Those cavities are also used at SuperKEKB. During the KEKB operation, Q values of some cavities were degraded. Cause of the degradation was contamination by air dusts at a repair of vacuum seals or a gasket replacement of input couplers. So far, those degradations are acceptable for the SuperKEKB operation, however, further degradation will make the operation unstable and, in the worst case, make it impossible. High pressure rinsing (HPR) is an effective method to clean the cavity surface. In order to apply HPR, however, the cavity has to be disassembled from a cryomodule. The disassembly takes time and costs. Furthermore, re-sealed vacuum flanges bring the risk of vacuum leakage again. Therefore we have developed a horizontal HPR. This method applies a high pressure water jet that is inserted horizontally into the cavity in the cryomodule. The wasted water is extracted with an aspirator. This method does not require the disassembly. We applied the horizontal HPR to our degraded cavity. Its RF performance has been successfully recovered.

TUP056

Industrialization of European XFEL Preparation Cycle “BCP Flash” at Ettore Zanon Company

cavity, controls, acceleration, pick-up

547

A. Matheisen, N. Krupka, M. Schalwat, A. Schmidt, W. Singer, N. Steinhau Kühl, B. van der Horst
DESY, Hamburg, Germany
G. Corniani
Ettore Zanon S.p.A., Schio, Italy
P. Michelato, L. Monaco
INFN/LASA, Segrate (MI), Italy

In the Specification for XFEL Cavity preparation (R1) two different preparation sequences are presented. Ettore Zanon Company as one of the two companies contracted for XFEL cavity production and preparation has chosen the so called BCP flash cycle. To fulfill the requested work flow and quality of infrastructure and processes, the company set up a complete new infrastructure in refurbished fabrication halls. The layout of the facility, set up of work flow of preparation and test results of resonators processed by E.Zanon in their infrastructure will be reported.
(R1) Series Surface and acceptance test preparation of superconducting cavities for the European Xfel (XFEL/A - D) JUNE 30, 2009

TUP058

Recent Findings on Nitrogen Treated Niobium

niobium, cavity, SRF, solenoid

558

R.G. Eichhorn, A. Ganshin, A. Holmes, J.J. Kaufman, S.R. Markham, S. Posen, E.N. Smith
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Recent findings on Nitrogen treated Niobiums Based on recent findings at Fermilab, Cornell investigated the role of Nitrogen being present during the cavity hydrogen degassing process. We treated several samples at different temperatures being exposed to nitrogen between 10 minutes and 3 hours at pressures around 15 mbar as well as single cell cavities. This contribution will summarize our findings from surface analysis, Tc measurements and cavity Qs, addressing the question, if such a process can form Niobium-Nitride.

TUP059

TM-Furnace Qualification at Cornell

cavity, SRF, cryomodule

561

F. Furuta, B. Bullock, R.G. Eichhorn, A. Ganshin, G.M. Ge, G.H. Hoffstaetter, J.J. Kaufman, M. Liepe, J. Sears
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Cornell's SRF group had new vacuum furnace for hydrogen degassing of SRF Nb cavity. Systematic study and testing have been done to qualify this new furnace. We will report the results of those qualification tests include cavity bake and vertical testing.

TUP062

Application of In-Vacuum Infrared Pyrometry During Fabrication of European XFEL Niobium Cavities

cavity, operation, electron, niobium

570

L. Monaco, P. Michelato, D. Sertore
INFN/LASA, Segrate (MI), Italy
V. Battista, G. Corniani, M. Festa
Ettore Zanon S.p.A., Schio, Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy

A technique to measure the temperature of Niobium components in vacuum during Electron Beam Welding (EBW) operation is presented and results obtained on the large scale cavity production for the European XFEL are discussed. During the EBW process, the knowledge of the components temperature during the welding operation could help both for the better choice of the welding parameters and for the optimization of the production cycle. In collaboration with the Italian firm Ettore Zanon (EZ), we developed a system able to measure the temperature of Nb components in vacuum during EBW operation using a IR pyrometer placed outside the vacuum chamber through an appropriate vacuum viewport. In the paper the experience of this device during the production of Nb components for the XFEL 1.3 GHz cavity production is discussed.

TUP067

Hydrogen Saturation and the Thermal Conductivity of Superconducting Niobium

niobium, cavity, superconductivity, lattice

589

S.K. Chandrasekaran
MSU, East Lansing, USA
T.R. Bieler
Michigan State University, East Lansing, USA
C. Compton
FRIB, East Lansing, USA
N.T. Wright
(MSU), East Lansing, USA

Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics, through Grant No. DE-S0004222
The thermal conductivity k of Nb at less than 3 K is dominated by phonon transport. In Nb with sufficiently few lattice imperfections, a maximum in k occurs at 1.8 K, called the phonon peak (PP). A large PP is desired to reduce potential local hot spots and contributes to an increased Q factor. The magnitude of the PP is sensitive to SRF cavity manufacturing processes. The effect of interstitial hydrogen on the magnitude of the PP is examined by subjecting two bicrystal Nb specimens to 300 C for 1 h in a 75% H2, 25% N2 atmosphere at 0.5 atm. Prior to hydrogen infusion, specimen 1 was heated to 800 C for 2 h, while specimen 2 was heated to 1100 C for 4 h. Both specimens displayed a 25% reduction in the PP due to the additional hydrogen, independent of their crystal orientations and heat treatment histories. An 800 C vacuum heating for 2 h was found to be sufficient to recover the PP in specimen 1, while an 1100 C heating for 4 h was required to recover the PP in one of the grains of specimen 2. The results suggest that hydrogen trapped in the Nb lattice will degas when the Nb is heated to at least the temperature to which it was heated at prior to the hydrogen infusion step.

TUP071

Development of Nb3Sn Cavity Vapor Diffusion Deposition System

niobium, cavity, impedance, controls

603

G.V. Eremeev, W.A. Clemens, K. Macha, H. Park, R.S. Williams
JLAB, Newport News, Virginia, USA
H. Park
ODU, Norfolk, Virginia, USA

Funding: Work supported by DOE. Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Alternative BCS superconductors with the superconducting critical temperature higher than that of niobium theoretically surpass the limitations of niobium. The feasibility of technology has been demonstrated at 1.5 GHz with Nb3Sn vapor deposition technique at Wuppertal University. The benefit at these frequencies is more pronounced at 4.2 K, where Nb3Sn coated cavities show RF resistances an order of magnitude lower than that of niobium. At Jefferson Lab we started the development of Nb3Sn vapor diffusion deposition system within an R&D development program towards compact light sources. Here we present the current progress of the system development.

TUP073

Niobium Coatings for the HIE-ISOLDE QWR Superconducting Accelerating Cavities

cavity, niobium, cathode, SRF

611

N.M. Jecklin, S. Calatroni, L.M.A. Ferreira, I. Mondino, A. Sublet, M. Therasse, W. Venturini Delsolaro
CERN, Geneva, Switzerland
B. Delaup
EPFL, Lausanne, Switzerland

The HIE-ISOLDE project is the upgrade of the existing ISOLDE facility at CERN, which is dedicated to the production of a large variety of radioactive ion beams for nuclear physics experiments. A new linac made of 20 β=10.3% and 12 β=6.3% QWR superconducting accelerating cavities at 101 MHz will be built, and in a first phase two cryomodules of 5 high-beta cavities each are scheduled to accelerate first beams in 2015. The cavities are made of a copper substrate, with a sputter-coated superconductive niobium layer, operated at 4.5 K with an accelerating field of 6 MV/m at 10W RF losses (Q0=4.5e8) In this paper we will discuss the baseline surface treatment and coating procedure which allows obtaining the required performance, as well as the steps undertaken in order to prepare series production of the required number of cavities guaranteeing their quality and functionality.

TUP092

MUSICC3D: a Code for Modeling the Multipacting

cavity, electron, simulation, RF-structure

683

T. Hamelin, M. Chabot, J.-L. Coacolo, J. Lesrel, G. Martinet
IPN, Orsay, France

IPNO has conducted an effort to develop a 3D code for modeling multipacting in RF structures. The MUSICC3D program is using particle in cell method. Based on Runge Kutta method and using relativistic equation of motion, it solves the trajectory of a particle (e-) in the RF field. The integrations over the multi differential Secondary Emission Yield (SEY) (E_in, Alpha_in ,E_out, Alpha_out)) is made with Montecarlo method. Two running modes are available. The first one is using a model of virtual particle (i.e. the charge of a unique particle “rebounding” in the interior of the cavity is made by the product of SEYs occurring at each interaction with the walls). The other one makes generation of a full cascade of individual electrons. Benchmarking calculations have been done with analytical calculations and 2D particle in cell code (MULTIPAC). In all these cases the effects of the different inputs for the multi differential SEY have been investigated. Its intend is to give a guide to determine which precision on the SEY is needed to perform accurate multipacting calculations. Benchmarking with real cavity has been recently started and results with QWR Spiral2 cavities are presented.
Hatch, Multipacting Modes etc., Physical Review.
Wood, Investigations into Multipactor Breakdown etc., ESA Journal.
Geng, Multipacting Simulations etc., Particule Accelerator Conference.

TUP094

Influence of Heat Treatments on Field Emitters on Nb Crystals

cavity, site, status, power-supply

690

S. Lagotzky, G. Müller
Bergische Universität Wuppertal, Wuppertal, Germany
A. Matheisen, D. Reschke
DESY, Hamburg, Germany

Funding: Funding by HGF Alliance and the BMBF project 05H12PX6
Systematic investigations of the enhanced field emission (EFE) of HPR-cleaned large grain (LG) and single crystal (SC) Nb samples (Ra < 0.5μm) revealed an exponential increase of the emitter number density N with electric surface field Es and strong activation effects of the remaining particulates. Different types of EFE activation were observed: by high E partially combined with a micro-discharge or by heat treatments (HT) [1]. In cavities, EFE activation might also occur due to enhanced rf losses of particulates. Therefore, we have started a test series with two LG and two SC typically prepared Nb samples (40 μm BCP, 140 μm EP and HPR at DESY). At first all emitters (1 nA) up to Es = 160 MV/m were localized by means of correlated field emission microscopy (FESM). Then systematically varied in-situ HT between 122°C (24 h) and 400°C (2 h) were applied to investigate the activation of emitters due to the change of the natural Nb oxide. For all samples a significant increase of N with stronger HT up to 32 emitters/cm² at 400°C were obtained resulting in some activated emitters already at Es = 40 MV/m. Final SEM images of the activated emitters will also be discussed.
[1] A. Navitski et. al, subm. to PRSTAB 2013

WEIOA02

Energetic Condensation Growth of Niobium Films

cavity, ion, lattice, plasma

761

M. Krishnan, I. Irfan
AASC, San Leandro, California, USA

Funding: The AASC research is supported by the US Department of Energy via several SBIR research grants
Energetic Condensation refers to thinfilm growth on a surface using ~100eV ions, versus lower energy deposition using sputtering (~1-10eV with no substrate bias) or still lower energy thermal evaporation. The relatively high incident energy of energetic condensation creates defects and vacancies within the first few atomic layers and enables diffusion to lower free-energy sites in the lattice. Shallow defects migrate to the heated surface and are annihilated, leading to low-defect crystal growth. It has been shown [1] that the purer the film, the closer are its superconducting parameters to those of the bulk metal. Use of cathodic arc plasmas was proposed in 2000 by Langner [TESLA Rep. 2000-15, Ed. D. Proch, DESY 2000], followed by detailed development of the process [2]. AASC picked up from the European Community-Research Infrastructure Activity and has demonstrated very high RRR=541 in Nb films grown on crystal substrates [3]. Ongoing work to coat 1.3GHz copper cavities using cathodic arc plasmas, as well as growth of higher temperature films such as NbTiN, Nb3Sn and MgB2 are described. A related technique for energetic condensation using an ECR plasma source is also described.
1. C. Benvenuti et al, IEEE Trans. Appl. Supercond. 9 (1999) 900
2. R. Russo et al, Supercond. Sci. Technol. 18 (2005) L41-L44
3. M. Krishnan et al, Supercond. Sci. Technol. 24, 115002 (2011)

Slides WEIOA02 [14.616 MB]

WEIOA03

Nb Sputtered Quarter Wave Resonators for the HIE-ISOLDE

cavity, cathode, niobium, linac

767

W. Venturini Delsolaro, S. Calatroni, A. D'Elia, B. Delaup, N.M. Jecklin, Y. Kadi, P. Maesen, I. Mondino, A. Sublet, M. Therasse
CERN, Geneva, Switzerland
A. D'Elia
UMAN, Manchester, United Kingdom
D.A. Franco Lespinasse, G. Keppel, V. Palmieri, S. Stark
INFN/LNL, Legnaro (PD), Italy

The HIE-ISOLDE superconducting linac will be based on quarter wave resonators (QWRs), made by Niobium sputtering on Copper. The operating frequency at 4.5 K is 101.28 MHz and the required performance for the high beta cavity is 6 MV/m accelerating field for 10 W maximum power dissipation. These challenging specifications were recently met at CERN at the end of a vigorous development program. The paper reports on the progress of the cavity RF performance with the evolution of the sputtering process; it equally illustrates the parallel R&D which is ongoing at CERN and at INFN in the quest for even higher performances.

Slides WEIOA03 [14.564 MB]

WEIOA04

Nb3Sn for SRF Application

niobium, cavity, SRF, laser

773

M. Liepe, S. Posen
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

The superconductor Nb3Sn is a promising alternative to standard niobium for SRF applications for two reasons: Its larger superconducting energy gap results in significantly lower BCS surface resistance at typical SRF operating temperatures. Additionally, theoretical predictions suggest that the maximum operating field of Nb3Sn cavities could be twice that of niobium cavities. Early work on a small number of Nb3Sn coated cavities indeed showed 2K to 4.2K quality factors well above what is achievable with niobium, though at accelerating fields below ~10 MV/m only. After many years of worldwide inactivity, Cornell has taken the lead and initiated a new R&D program on Nb3Sn to explore its full potential for SRF applications. New facilities for coating cavities with Nb3Sn have been set up at Cornell, and 1.3 GHz single cell cavities have been coated and tested. This talk presents the Cornell Nb3Sn program, discusses first promising results obtained, and also gives an overview of other Nb3Sn SRF work worldwide.

Slides WEIOA04 [3.854 MB]

WEIOC02

Multilayers Activities at Saclay / Orsay

niobium, cavity, SRF, superconductivity

789

C. B. Baumier, G. Martinet
IPN, Orsay, France
C.Z. Antoine
CEA/IRFU, Gif-sur-Yvette, France
F. F. Fortuna
CSNSM, ORSAY CAMPUS, France
J.C. Villegier
CEA/INAC, Grenoble Cedex 9, France

In the investigations on the high gradient SRF cavities, the superconducting multilayer is a promising alternative. The predictions show that an SIS (Superconductor/Isolator/Superconductor) nano-composite could improve the efficiency limited by the bulk Nb it-self used today for accelerating cavities. We start, at the IPNO lab in collaboration with the CSNSM lab (CNRS) and Irfu lab (CEA), an experimental study to test the screening effect on multilayer assemblies. Based on 3rd harmonic magnetometer and a TE011 SRF cavity, measurements of first critical magnetic field HC1 and surface resistance of samples have been performed. Along with these first results, we are starting the development of a MBE deposition. This set-up is devoted to optimise the best organisation of the multilayer to produce the model sample, and to find, in a close future, a realistic solution to apply this technique on an accelerating SRF cavity.
Labex P2IO funding

Slides WEIOC02 [3.035 MB]

THIOA02

The Challenge to Assemble 100 Cryomodules for the European E-XFEL

cryomodule, cavity, controls, linac

816

C. Madec
CEA, Gif-sur-Yvette, France
S. Berry, J.-P. Charrier, M. Fontaine, Y. Gasser, O. Napoly, C.S. Simon, T.V. Vacher, B. Visentin
CEA/DSM/IRFU, France
P. Charon, C. Cloué, G. Monnereau, J.L. Perrin, D. Roudier, Y. Sauce, T. Trublet
CEA/IRFU, Gif-sur-Yvette, France

As In-Kind contributor to the E-XFEL project, CEA is committed to the integration on the Saclay site of the 100 cryomodules (CM) of the superconducting linac as well as to the procurement of miscellaneous parts including 31 cold beam position monitors (BPM) of the re-entrant type. The assembly infrastructure has been renovated from the previous Saturne Synchrotron Laboratory facility: it includes a 200 m2 clean room complex with 112 m2 under ISO4, 1325 m2 of assembly platforms and 400 m2 of storage area. In parallel, CEA has conducted industrial studies and three cryomodule assembly prototyping both aiming at preparing the industrial file, the quality management system and the commissioning of the assembly plant, tooling and control equipment. In 2012, the contract of the integration has been awarded to ALSYOM. The first pre-series modules have been assembled and are being tested at DESY. This paper will present the challenges of the module integration from the preparation phase to the industrial phase.

Slides THIOA02 [17.641 MB]

THIOA04

Low-Beta Cryomodule Design Optimized for Large-Scale Linac Installations

cryomodule, alignment, solenoid, cryogenics

825

S.J. Miller, B. Bird, N.K. Bultman, F. Casagrande, A.D. Fox, M.J. Johnson, M. Leitner, T. Nellis, J.P. Ozelis, X. Rao, R.J. Rose, M. Shuptar, K. Witgen, Y. Xu
FRIB, East Lansing, Michigan, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
This paper will present most recent design developments at FRIB to optimize low-beta cryomodules for large-scale linac installations. FRIB, which requires the fabrication of 53 cryomodules, has to emphasize ease of assembly and alignment plus low cost. This paper will present experimental results of a novel kinematic rail support system which significantly eases cryomodule assembly. Design choices for mass-production are presented. Results of vibration calculations and measurements on a FRIB prototype cryomodule will be reported.

Slides THIOA04 [10.842 MB]

THIOB01

CEBAF Upgrade: Cryomodule Performance and Lessons Learned

cryomodule, cavity, linac, controls

836

M.A. Drury, J. Hogan, C. Hovater, L.K. King, H. Park, J.P. Preble, R.A. Rimmer, H. Wang, M. Wiseman
JLAB, Newport News, Virginia, USA
G.K. Davis, C.E. Reece
JLab, Newport News, Virginia, USA
F. Marhauser
Muons, Inc, Illinois, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract DE-AC05-06OR23177.
The Thomas Jefferson National Accelerator Facility is currently engaged in the 12 GeV Upgrade Project. The goal of the 12 GeV Upgrade is a doubling of the available beam energy of the Continuous Electron Beam Accelerator Facility (CEBAF) from 6 GeV to 12 GeV. The increase in beam energy will largely be due to the addition of ten C100 cryomodules and the associated RF in the CEBAF linacs. These cryomodules are designed to deliver 100 MeV per cryomodule. Each C100 cryomodule contains a string of eight seven-cell, electro-polished, superconducting RF cavities. While an average performance of 100 MV is needed to achieve the overall 12 GeV beam energy goal, the actual performance goal for the cryomodules is an average energy gain of 108 MV to provide operational headroom. All ten of the C100 cryomodules are installed in the linac tunnels and are on schedule to be commissioned by September 2013. Commissioned performance has ranged from 104 MV to 118 MV. In May, 2012, a test of an early C100 achieved 108 MV with full beam loading. This paper will discuss the performance of the C100 cryomodules along with operational challenges and lessons learned for future designs.
The U.S. Govt. retains a non-exclusive, paid-up,irrevocable,world-wide license to publish or reproduce this manuscript.

Slides THIOB01 [2.534 MB]

THIOD02

Faced Issues in ReA3 Quarter-Wave Resonators and Their Successful Resolution

cavity, linac, cryomodule, operation

873

A. Facco
NSCL, East Lansing, Michigan, USA
C. Compton, J.L. Crisp, K. Elliott, A. Facco, M. Hodek, M.J. Johnson, M. Leitner, I.M. Malloch, D. Miller, S.J. Miller, D. Morris, D. Norton, R. Oweiss, J.P. Ozelis, J. Popielarski, L. Popielarski, K. Saito, N.R. Usher, G.J. Velianoff, D.R. Victory, J. Wei, K. Witgen, Y. Xu, S. Zhao
FRIB, East Lansing, Michigan, USA
A. Facco
INFN/LNL, Legnaro (PD), Italy

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
The 80.5 MHz, β=0.085 QWR production cavities for the ReA3 project at MSU have initially shown puzzling behavior and unexpected lack of performance. This was due to a combination of design problems and subtle mechanical effects which have been pointed out during a brief but intense testing campaign made by the FRIB SRF group. The same cavities could be eventually refurbished and brought to performance well above original specifications. This work will be presented with emphasis to the technical problems encountered, their diagnosis and the adopted solutions.

Slides THIOD02 [8.256 MB]

THP005

Characteristics and Fabrication of Spoke Cavities for High-Velocity Applications

cavity, operation, target, superconductivity

902

C.S. Hopper, J.R. Delayen, H. Park
ODU, Norfolk, Virginia, USA
J.R. Delayen, H. Park
JLAB, Newport News, Virginia, USA

A 500 MHz, velocity-of-light, two-spoke cavity has been designed and optimized for possible use in a compact light source [1]. Here we present the mechanical analysis and steps taken in fabrication of this cavity at Jefferson Lab.
*[1] T. Satogata et al, “Compact Accelerator Design for a Compact Light Source,” IPAC13, Shanghai, China, May 2013.

THP012

Rebuild of Capture Cavity 1 at Fermilab

cavity, cryomodule, operation, SRF

917

E.R. Harms, T.T. Arkan, E. Borissov, N. Dhanaraj, A. Hocker, Y.O. Orlov, T.J. Peterson, K.S. Premo
Fermilab, Batavia, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The front end of the proposed Advanced Superconducting Test Accelerator at Fermilab employs two single cavity cryomodules, known as ‘Capture Cavity 1’ and ‘Capture Cavity 2’, for the first stage of acceleration. Capture Cavity 1 was previously used as the accelerating structure for the A0 Photoinjector to a peak energy of ~14 Mev. In its new location a gradient of ~25 MV/m is required. This has necessitated a major rebuild of the cryomodule including replacement of the cavity with a higher gradient one. Retrofitting the cavity and making upgrades to the module required significant re-design. The design choices and their rationale, summary of the rebuild, and early test results are presented.

THP024

Lorentz Force Detuning Simulations of Spoke Cavities With Different Stiffening Elements

cavity, simulation, radiation, operation

946

J.L. Muñoz, F.J. Bermejo
ESS Bilbao, Zamudio, Spain

Lorentz force detuning caused by radiation pressure on the Nb cavity walls is of concern in cavity design and operation since its magnitude can approach the cavity bandwidth. This effect can be reduced using pasive stiffening elements in the cavity. In this work, Lorentz force detuning has been studied by numerical simulations for spoke cavities. Different stiffening elements has been considered. Static and dynamic behaviour have been analyzed by means of 3D static and transient electromagnetic and mechanical coupled finite elements simulations.

THP026

Cage Cavity: A Low Cost, High Performance SRF Accelerating Structure

cavity, SRF, HOM, simulation

950

J. Noonan, T.L. Smith, M. Virgo, G.J. Waldschmidt
ANL, Argonne, USA
J.W. Lewellen
LANL, Los Alamos, New Mexico, USA

Funding: Funded by Office of Naval Research. Argonne National Laboratory is operated by UChicago-Argonne LLC for the Department of Energy
The Cage Cavity is a new SRF cavity technology using tubes formed into the shape of a solid wall cavity then assembled into a closed volume. The theory is that the cage cavity will form a resonant cavity at RF frequencies below a critical frequency at which the cage structure behaves as a solid structure. Several cage cavity structures have been fabricated and measured that demonstrate good RF properties. Comparison of simulations and measurements for these structures will be discussed. More importantly, simulations have identified a new cage cavity configuration in which an SRF cage cavity’s quality factor is greater than 10exp10. The cage cavity must operate in a vacuum vessel which is also an RF cavity. By choosing the cage cavity resonant frequency to be decoupled from the vessel higher order resonances, simulations show that the cage cavity Q is ~95% of a solid wall SRF cavity. The Cage Cavity design, fabrication costs, and high order mode behavior have a number of advantages over solid wall cavities. However, the cage cavity also has limitations. The design and properties of the cage cavity will be discussed and compared with existing SRF cavities.

THP050

Development of Power Coupler for Superconducting Spoke Cavities for China ADS Proton Linac

cavity, coupling, simulation, Windows

1024

X. Chen, T.M. Huang, H.Y. Lin, Q. Ma, F. Meng, W.M. Pan, Y.H. Peng
IHEP, Beijing, People's Republic of China

Abstract: The China-ADS proton linac adopts β=0.12 superconducting Spoke cavities. Each cavity is powered via a 325MHz coaxial power coupler. The coupler is to feed 6kW maximum power though it is designed to handle at 15kW .Two coupler sets have been made by IHEP so far, and a 10kW RF power in continuous travelling wave mode has passed through the coupler during high power test in late January 2013. An introduction of this coupler design and the room temperature test results are presented in this paper.

THP052

Cornell’s Beam Line Higher Order Mode Absorbers

HOM, linac, cryomodule, damping

1027

R.G. Eichhorn, J.V. Conway, Y. He, Y. Li, T.I. O'Connel, P. Quigley, J. Sears, N.R.A. Valles
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
V.D. Shemelin
Cornell University, Ithaca, New York, USA

Efficient damping of the higher-order modes (HOMs) of the superconducting cavities is essential for the proposed energy recovery linac at Cornell that aims for high beam currents and short bunches. Designing these HOM beamline absorbers has been a long endeavor, sometimes including disappointing results. We will review the design, the findings on the prototype and the final choices made for the 7 HOM absorbers being built for the main linac cryomodule (MLC) prototype.

THP054

Last Spiral 2 Couplers Preparation and RF Conditioning

cryomodule, multipactoring, controls, cavity

1036

Y. Gómez Martínez, M.A. Baylac, P. Boge, T. Cabanel, P. De Lamberterie, M. Marton, R. Micoud
LPSC, Grenoble Cedex, France

Six crymodules are ready to be installed in the SPIRAL 2 LINAC. We present here the protocols used for the preparation and for the RF conditioning of the couplers and the obtained results.

THP055

Ferrite Covered Ceramic Break HOM Damper

cavity, gun, HOM, damping

1040

H. Hahn, S.A. Belomestnykh, I. Ben-Zvi, L.R. Hammons, V. Litvinenko, R.J. Todd, D. Weiss, W. Xu
BNL, Upton, Long Island, New York, USA
A. Burrill
HZB, Berlin, Germany
J. Dai
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under contract no. DE-AC02-98CH10886 with the DOE.
The Brookhaven Energy Recovery Linac (ERL) is operated as R&D setup for high-current, high charge electron beams. It is comprised of a superconducting (SC) five-cell cavity and a half-cell SC photoinjector electron RF gun. Achieving the performance objectives requires effective HOM damping in the linac and gun cavity. Among the HOM dampers being developed is a beam-tube type HOM load for the electron gun consisting of a ceramic break surrounded by ferrite tiles. This design is innovative in its approach and achieves a variety of ends including broadband HOM damping and protection of the superconducting cavity from potential damage of the separately cooled ferrite tiles. The damper properties are described by the coupling impedance to a beam and the external Q to constrain the unloaded mode Q’s. Measured results for the gun damper at room and superconducting temperatures are presented

THP056

Validation Procedures for the IFMIF Power Coupler Prototypes

operation, controls, target, linac

1043

H. Jenhani, P. Carbonnier, Y. Gasser, N. Grouas, P. Hardy, V.M. Hennion, F. Orsini, Y. Penichot, B. Renard, D. Roudier
CEA/IRFU, Gif-sur-Yvette, France
S.J. Einarson, T.A. Treado
CPI, Beverley, Massachusetts, USA
D. Regidor, M. Weber
CIEMAT, Madrid, Spain

In the framework of the International Fusion Materials Irradiation Facility (IFMIF), which consists of two high power CW accelerator drivers, each delivering a 125 mA deuteron beam at 40 MeV, a Linear IFMIF Prototype Accelerator (LIPAc) is presently under design for the first phase of the project. The first two IFMIF Power Coupler Prototypes were manufactured for LIPAc. Series of acceptance tests have been performed successfully. Prototype Power Couplers have been then cleaned and assembled in an ISO 5 cleanroom. A dedicated test bench allowing RF conditioning of the couplers up to 200 kW CW at 175 MHz was achieved. RF power conditioning is planned to start during October 2013.

THP065

Design of 352.21 MHz RF Power Input Coupler and Window for the European Spallation Source Project (ESS)

operation, cavity, multipactoring, SRF

1069

E. Rampnoux, S. Bousson, S. Brault, P. Duchesne, P. Duthil, G. Olry, D. Reynet
IPN, Orsay, France

A 352.21 MHz RF high power coupler window was designed by IPNO to meet the specification requirements for the ESS accelerator project. This designed is based on IPNO’s power coupler developments performed in the framework of the EURISOL Design Study project for which two power couplers using coaxial technology without chokes systems around the ceramic disc have been designed and tested successfully up to 20 kW RF power level in CW mode. For ESS project, the RF power input window was developed and designed to reliability operate at an average power level of 25 kW up to 300 kW in pulsed and continuous wave modes. This 352.21 MHz RF window was developed to remove the chocks usually used and provided the following advantages: more reliability, less expensive to manufacture, better vacuum, easier cleaning, less secondary electron-multipacting with specificity to present a bandwidth close to 1 GHz.

THP067

Testing of Copper Plating Quality on ReA3 Coupler Bellows and Approach to Improved Plating for FRIB Production

SRF, experiment, cavity, controls

1077

L. Popielarski, M. Goodrich, M. Hodek, I.M. Malloch, N.M. Nicholas, R. Oweiss, J. Popielarski, N. Putnam, K. Saito, D.R. Victory
FRIB, East Lansing, Michigan, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
The SRF community faces difficulties finding repeatable, quality copper plating for fundamental power coupler (FPC) components. The copper plating of ten small custom bellows of β=0.085 Quarter-Wave Resonator (QWR) variable couplers for the ReAccelerator project has presented technical challenges. An improvement plan has been established and includes: better defining plating requirements and specification, creating testing processes to assure plating quality (Acceptance Criteria Listing (ACL)), identify viable plating vendors, develop clean, robust plating fixtures, procedures and quality assurance steps with multiple vendors, and perform ACL testing on plated bellows. A total of 24 prototype and production plated bellows are analyzed through acceptance testing, which include a vacuum leak check, tape test, 1000 psi water rinse, thermal cycle at 77K, borescope inspection and final leak check. Select bellows have been processed and tested with a quarter-wave resonator. A summary of the plating improvement program, plated bellows acceptance statistics, and RF test results will be reported.

THP072

Input Coupler for Cornell ERL Main Linac

linac, cavity, cryomodule, operation

1094

V. Veshcherevich, P. Quigley
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work is supported by the National Science Foundation grant DMR-0807731.
Each cavity of the Cornell ERL Main Linac has a single coaxial type input coupler with fixed coupling, Qext = 6.5×E7. The input coupler will operate at RF power up to 5 kW at full reflection. The coupler design is based on the design of TTF-III input coupler with appropriate modifications and with taking into account the Cornell experience with couplers for ERL Injector. Seven couplers have been fabricated by CPI, Beverly and tested at Cornell on the test stand up to 5 kW CW. No major issues were noticed during the test. One coupler was attached to the prototype linac cavity. The cavity was successfully tested with great results achieved inside the horizontal test cryomodule. Six other couplers will be installed in the Main Linac Cryomodule (MLC) Prototype.

THP073

HOM Dampers and Waveguide for the Short Pulse X-Ray (SPX) Project

HOM, cavity, cryomodule, damping

1098

G.J. Waldschmidt, B. Brajuskovic, D.J. Bromberek, J.D. Fuerst, J.P. Holzbauer, A. Nassiri, Y. Shiroyanagi, G. Wu
ANL, Argonne, USA
V.D. Shemelin
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
The production of HOM dampers for the superconducting SPX cavities has been undertaken at the Advanced Photon Source. The dampers are vacuum compatible loads that utilize a four wedge design in WR284 rectangular waveguide. The rf lossy material consists of hexoloy silicon carbide (SiC) due to its suitable mechanical and electrical material properties. Issues regarding manufacturing consist of initial SiC material failure due to fabrication stresses as well as substandard soldering bonds of the SiC to the copper damper bodies. In addition, integration into the cryomodule consists of rf, thermal, and mechanical design considerations of the dampers and the waveguide transmission lines. An analysis of the manufacturing and integration issues and remedies are discussed further in this paper.

THP079

Improvement of the Pneumatic Frequency Tuner of the Superconducting Resonators at IUAC

controls, linac, cavity, feedback

1107

A. Pandey, G.K. Chaudhari, R.N. Dutt, S. Ghosh, D. Kanjilal, J. Karmakar, D.S. Mathuria, P. Patra, A. Rai, A. Roy, B.K. Sahu, S.K. Saini
IUAC, New Delhi, India

The existing phase locking scheme of the quarter wave resonators used in superconducting linear accelerator of Inter University Accelerator Centre consists of a fast (electronic) and a slow time scale (pneumatic) control. Presently, helium gas operated mechanical tuners are being used to phase lock the resonators against the master oscillator frequency and different ion beams have been accelerated and delivered to conduct experiments. The present pneumatic frequency tuner has two limitations: (a) no proportional flow control in vacuum condition (b) large hysteresis problem in the proportional valve responsible for gas flow control. Due to these limitations, the system becomes non-linear and the response time is very slow (~sec). Using the existing system, phase locking of a resonator becomes delicate and time consuming. In addition, it was found to be difficult to implement auto phase locking mechanism on the resonator. To overcome these problems and to improve the dynamics of the existing tuner, a new pneumatic tuning system has been adopted. Details of the existing tuning mechanism and the modified tuning system along with the test results will be presented in the paper.

THP080

SRF Cavity Tuning for Low Beam Loading

cavity, resonance, operation, cryomodule

1110

N. Solyak, E. Borissov, I.V. Gonin, C.J. Grimm, T.N. Khabiboulline, R.V. Pilipenko, Y.M. Pischalnikov, W. Schappert, V.P. Yakovlev
Fermilab, Batavia, USA

The design of 5-cell elliptical 650 MHz β=0.9 cavities to accelerate H⁻ beam of 1 mA average current in the range 467-3000 MeV for the Project X Linac is currently under development at Fermilab. The low beam current enables cavities to operate with high loaded Q’s and low bandwidth, making them very sensitive to microphonics. Mechanical vibrations and the Lorentz force can drive cavities off resonance during operation; therefore the proper design of the tuning system is very important part of cavity mechanical design. In this paper we review the design, performance, operation, reliability and cost of fast and slow tuners for 1.3 GHz elliptical cavities. We also present a design of the slow and fast tuners for 650 MHz β=0.9 cavities based on this experience. The HV in the new design is equipped with the tuners located at the end of the cavity instead of the initially proposed blade tuner located in the middle. We will present the results of ANSYS analyses of mechanical properties of tuners.

FRIOB02

Development and Performance of 325 MHz Single Spoke Resonators for Project X

cavity, operation, niobium, electron

1187

L. Ristori, M.H. Awida, P. Berrutti, C.M. Ginsburg, I.V. Gonin, T.N. Khabiboulline, M. Merio, T.H. Nicol, D. Passarelli, A.M. Rowe, D.A. Sergatskov, A.I. Sukhanov, V.P. Yakovlev
Fermilab, Batavia, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
Two types of single spoke resonators will be utilized for beam-acceleration in the low energy part of the Project X linac. SSR1 and SSR2 operate at 325 MHz and at an optimal beta of 0.22 and 0.51 respectively. After the initial phase of prototyping, a production run of 10 SSR1 resonators was recently completed in US industry. The qualification of this group of resonators in the Fermilab VTS is proceeding successfully and nearly complete. The first qualified resonator has been outfitted with a Stainless Steel helium vessel. Preliminary test results for the first jacketed SSR1 are presented. The first RF power couplers were ordered, the design of the double-lever tuning mechanism is almost complete.

Slides FRIOB02 [8.800 MB]