SRF2013 - List of Keywords (ion)

Paper	Title	Other Keywords	Page
MOIOA01	The FRIB Project at MSU	cavity, cryomodule, linac, operation	1
	M. Leitner, B. Bird, F. Casagrande, S. Chouhan, C. Compton, J.L. Crisp, K. Elliott, A. Facco, A.D. Fox, M. Hodek, M.J. Johnson, G. Kiupel, I.M. Malloch, D. Miller, S.J. Miller, D. Morris, D. Norton, R. Oweiss, J.P. Ozelis, J. Popielarski, L. Popielarski, A.P. Rauch, R.J. Rose, K. Saito, M. Shuptar, N.R. Usher, G.J. Velianoff, D.R. Victory, J. Wei, J. Whitaker, K. Witgen, T. Xu, Y. Xu, O. Yair, S. Zhao FRIB, East Lansing, 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 Facility for Rare Isotope Beams (FRIB) is ready to start construction. The facility will utilize a high-intensity, heavy-ion driver linac to provide stable ion beams from protons to uranium up to energies of >200 MeV/u and at a beam power of up to 400 kW. The superconducting cw linac consists of 330 individual low-beta (β = 0.041, 0.085, 0.29, and 0.53 at 80.5 MHz and 322 MHz) cavities in 49 cryomodules operating at 2 K. This paper discusses the current development status of the project with emphasis on the linac SRF acquisition. SRF coldmass and cryomodule component designs are briefly summarized. A SRF production facility, currently under construction, is described.
	Slides MOIOA01 [9.804 MB]

MOIOA02	Status and Challenges of Spiral2 SRF Linac	cryomodule, linac, cavity, vacuum	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]

MOIOA05	SRF in Heavy Ions Projects	cavity, linac, heavy-ion, cryomodule	30
	D. Jeon IBS, Daejeon, Republic of Korea
	SRF technologies are widely applied to heavy ion accelerator projects in the world such as the RAON, C-ADS, HIAF, FRIB, SPIRAL2, ISAC-II, HIE-ISOLDE etc. In this talk, status report, design choices and SRF challenges met in heavy ion machines are presented.
	Slides MOIOA05 [10.228 MB]

MOP008	SUPERCONDUCTING LINAC FOR THE RISP	linac, cavity, cryomodule, proton	89
	H.J. Kim, H.J. Cha, M.O. Hyun, H.J. Jang, D. Jeon, J.D. Joo, M.J. Joung, H.C. Jung, Y. Jung, Y. Kim, M. Lee, G.-T. Park IBS, Daejeon, Republic of Korea
	The RISP (Rare Isotope Science Project) accelerator has been planned to study heavy ion of nuclear, material and medical science at the Institute for Basic Science (IBS). It can deliver ions from proton to Uranium. The facility consists of three superconducting linacs of which superconducting cavities are independently phased. Requirement of the linac design is especially high for acceleration of multiple charge beams. In this paper, we present the RISP linac design, the superconducting cavity, and cryomodule.

MOP012	Completion of the Superconducting Heavy Ion Linac at Inter-University Accelerator Centre	linac, operation, electronics, controls	103
	A. Rai, R. Ahuja, J. Antony, S. Babu, J. Chacko, G.K. Chaudhari, A. Chaudhary, T.S. Datta, R.N. Dutt, S. Ghosh, R. Joshi, D. Kanjilal, S. Kar, J. Karmakar, M. Kumar, R. Kumar, D.S. Mathuria, R. Mehta, K.K. Mistri, A. Pandey, P. Patra, P.N. Prakash, A. Roy, J. Sacharias, B.K. Sahu, A. Sarkar, S.S.K. Sonti, S. K. Suman, J. Zacharias IUAC, New Delhi, India
	The Superconducting heavy ion Linac at Inter University Accelerator Centre (IUAC), New Delhi has been delivering accelerated ion beams to the users since 2009 . Initially the first accelerating module, housing eight Quarter Wave Resonators (QWR’s), became operational together with the Superbuncher having one and the Rebuncher having two QWR’s, respectively. In the subsequent years, the remaining two modules have been installed and commissioned. The complete Linac was operated recently and several ion beams were delivered for scheduled experiments. The maximum energy gain was 8 MeV per charge state. Operational highlights include successful operation of four resonators in the third module with Piezo based * mechanical tuning, implementation of remote phase locking for all resonators in three modules, development of a scheme for auto locking of resonators and testing of a capacitive pickup as a beam diagnostic element. Details will be presented vis-à-vis the problems encountered and the future course of action. * A. Rai et. al., Proc. of SRF2009 Sept. 20–25, 2009, Berlin, Germany, page 244. ** B.K.Sahu et. al., Proc. of IPAC 2010, Kyoto Japan, page 2920.

MOP021	Conceptual Design of SC Linac for RIBF-Upgrade Plan	linac, cryomodule, cavity, quadrupole	137
	K. Yamada, O. Kamigaito, N. Sakamoto, K. Suda RIKEN Nishina Center, Wako, Japan
	For the intensity upgrade of very-heavy ions such as 238U and 124Xe at the RIKEN RI-Beam Factory (RIBF), a design study of new SC linac injector has started on. In the RIBF, the very-heavy ions are accelerated in a cascade of the injector linac (RILAC2), the RIKEN ring cyclotron (RRC), the fixed-frequency ring cyclotron (fRC), the intermediate-stage ring cyclotron (IRC), and the world's first superconducting ring cyclotron (SRC). We plan to substitute the SC linac for the RRC with respect to the very heavy ions, and to boost up the energy of ions with mass-to-charge ratio of 7 from 1.4 MeV/u to 11 MeV/u in the cw mode. The SC cavity is assumed to be a two gap QWR with an rf frequency of 73 MHz, that is twice the rf frequency of IRC and SRC. The cell parameters and number of cavity are determined by calculating the energy gain of synchronous ion by taking the rf phase at the center of gap into account. The transverse motion is calculated by the transfer matrix method and several types of lattice are studied. This contribution reports the progress of design study for the SC linac.

MOP059	Management for the Long-Term Reliability of the Diamond Superconducting RF Cavities	cavity, vacuum, SRF, 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.

TUP075	Design and Commissioning Status of New Cylindrical HiPIMS Nb Coating System for SRF Cavities	cavity, niobium, cathode, SRF	617
	H.L. Phillips, K. Macha, A-M. Valente-Feliciano JLAB, Newport News, Virginia, USA
	Funding: † Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. For the past 19 years Jefferson Lab has sustained a program studying niobium films deposited on small samples in order to develop an understanding of the correlation between deposition parameters, film micro-structure, and RF performance. A new cavity deposition system employing a cylindrical cathode using the HiPIMS technique has been developed to apply this work to cylindrical cavities. The status of this system will be presented.

TUP079	ECR Nb Films Grown on Amorphous and Crystalline Cu Substrates: Influence of Ion Energy	ECR, SRF, interface, electron	631
	A-M. Valente-Feliciano, G.V. Eremeev, H.L. Phillips, C.E. Reece JLAB, Newport News, Virginia, USA C. Cao Illinois Institute of Technology, Chicago, IL, USA Th. Proslier ANL, Argonne, USA J.K. Spradlin JLab, Newport News, Virginia, USA T. Tao UIC, Chicago, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. In the pursuit of niobium (Nb) films with similar performance with the commonly used bulk Nb surfaces for Superconducting RF (SRF) applications, significant progress has been made with the development of energetic condensation deposition techniques. Using energetic condensation of ions extracted from plasma generated by Electron Cyclotron Resonance, it has been demonstrated that Nb films with good structural properties and RRR comparable to bulk values can be produced on metallic substrates. The controlled incoming ion energy enables a number of processes such as desorption of adsorbed species, enhanced mobility of surface atoms and sub-implantation of impinging ions, thus producing improved film structures at lower process temperatures. Particular attention is given to the nucleation conditions to create a favorable template for growing the final surface exposed to SRF fields. The influence of the deposition energy for both hetero-epitaxial and fiber growth modes on copper substrates is investigated with the characterization of the film surface, structure, superconducting properties and RF performance.

TUP082	Materials Analysis of CED Nb Films Being Coated on Bulk Nb Single Cell SRF Cavities	cavity, SRF, HOM, cryogenics	638
	X. Zhao, C.E. Reece JLab, Newport News, Virginia, USA G. Ciovati Jefferson Lab, Newport News, Virginia, USA I. Irfan, C. James, M. Krishnan AASC, San Leandro, California, USA A.D. Palczewski JLAB, Newport News, Virginia, USA
	Funding: This research is supported at AASC by DOE via Grant No. DE-FG02-08ER85162 and Grant No. DE-SC0004994 and by Jefferson Science Associates, LLC under U.S. DOE Contract No. DEAC05- 06OR23177 This study is an on-going research on depositing a Nb film on the internal wall of bulk Nb single cell SRF cavities, via an coaxial energetic condensation (CED) facility at AASC company. The motivation is to firstly create a homoepitaxy-like Nb/Nb film in a scale of a ~1.5GHz RF single cell cavity. Next, through SRF measurement and materials analysis, it might reveal the baseline properties of the CED-type homoepitaxy Nb films. Such knowledge of Nb-Nb homo-epitaxy is useful to create future realistic SRF cavity film coatings, such as hetero-epitaxy Nb/Cu Films, or template-layer-mitigated Nb films. One large-grain, and three fine grain bulk Nb cavity were coated. They went through cryogenic RF measurement. Preliminary results show that the Q0 of a Nb film at 2 K and low rf field, produced by CED, could be close to that of the pre-coated bulk Nb surface (being CBP'ed plus a light EP); but the quality drops rapidly for increasing rf field. We are investigating if the severe Q0-slope is caused by hydrogen incorporation before deposition, or is determined by some structural defects during Nb film growth.

TUP093	Field Emitter Current Conditioning on Nb Single Crystals with Different Roughness due to Varying EP/BCP Ratio	site, gun, controls, damping	686
	S. Lagotzky, G. Müller Bergische Universität Wuppertal, Wuppertal, Germany P. Kneisel JLAB, Newport News, Virginia, USA
	Funding: Funding by the BMBF project 05H12PX6 Enhanced field emission (EFE) from particulate contaminations and surface irregularities is one of the main field limitations of the superconducting Nb cavities required for XFEL and ILC. While the number density of particulate emitters can be reduced by dry ice cleaning (DIC) and clean room assembly, the optimum choice of crystallinity and polishing are still under discussion [1]. For the future ILC cavities, large or even single crystal Nb with a combination of BCP and EP is considered. Therefore, we have systematically investigated the EFE of single crystal Nb samples which got the same total polishing depth 136-138 μm but a different EP/BCP ratio (5.80, 2.40, 0.73, 0.15) and DIC by means of correlated optical/AFM profilometry, field emission scaning microscopy (FESM) and high-resolution SEM. Depending on the surface roughness (Ra < 200 nm), field enhancement factors b of 12 – 42 and emitting areas S up to 0.1 μm² were obtained. High current conditioning (μA - mA) of these emitters usually resulted in a slight reduction of b (factor < 2) but a strong increase of S. The influence of the surface roughness on the EFE and conditioning of the remaining emitters will be discussed. [1] Reschke et al., Phys. Rev. ST Accel. Beams 13, 071001-1 (2010)

WEIOA01	HiPIMS: a New Generation of Film Deposition Techniques for SRF Applications	SRF, cavity, plasma, target	754
	A-M. Valente-Feliciano JLAB, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Over the years, Nb/Cu technology, despite its shortcomings due to the commonly used magnetron sputtering, has positioned itself as an alternative route for the future of accelerator superconducting structures. Avenues for the production of thin films tailored for Superconducting RF (SRF) applications are showing promise with recent developments in ionized PVD coating techniques, i.e. vacuum deposition techniques using energetic ions. Among these techniques, High power impulse magnetron sputtering (HiPIMS) is a promising emerging technique which combines magnetron sputtering with a pulsed power approach. This contribution describes the benefits of energetic condensation for SRF films and the characteristics of the HiPIMS technology. It describes the on-going efforts pursued in different institutions to exploit the potential of this technology to produce bulk-like Nb films and go beyond Nb performance with the development of film systems, based on other superconducting materials and multilayer structures.
	Slides WEIOA01 [12.446 MB]

WEIOA02	Energetic Condensation Growth of Niobium Films	cavity, lattice, plasma, vacuum	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]

THIOC01	Low Beta Cavity Development for an ATLAS Intensity Upgrade	cavity, cryomodule, niobium, linac	850
	M.P. Kelly, Z.A. Conway, S.M. Gerbick, M. Kedzie, S.H. Kim, R.C. Murphy, B. Mustapha, P.N. Ostroumov, T. Reid ANL, Argonne, USA
	The set of seven new 72 MHz quarter wave SC (QWR) cavities has been completed and is being installed in the ATLAS heavy-ion accelerator at Argonne. The aim is to provide at least 17.5 MV accelerating potential with large acceptance and minimal beam losses for high intensity ion beams. The cavity electromagnetic design uses optimizations not used before with QWR including a large taper on both the inner and outer conductors in order to reduce surface fields and make efficient use of space along the beam line. Electropolishing (EP) on the finished cavities with integral helium jacket and no demountable RF joints has been performed, and is the first for any low beta SC cavity. This type of EP, adapted from Argonne systems for the linear collider effort, appears to have a large benefit in terms of the average quench field which range between 103-165 mT for five QWR tested to date. Cavity residual resistances at the proposed operating point of ~70 mT are low, clustering close to a value of ~2nOhm. Additional technical details including the almost exclusive use of wire EDM for niobium fabrication and a new CW 4 kW RF power coupler are presented.
	Slides THIOC01 [10.152 MB]

THP003	Cold Measurements on the 325 MHz CH-Cavity	cavity, linac, coupling, operation	896
	M. Busch, F.D. Dziuba, H. Podlech, U. Ratzinger IAP, Frankfurt am Main, Germany M. Amberg HIM, Mainz, Germany
	Funding: GSI, BMBF Contr. No. 06FY7102, 06FY9089I At the Institute for Applied Physics (IAP), Frankfurt University, a sc 325 MHz CH-Cavity has been designed and built. This 7-cell cavity has a geometrical beta of 0.16 corresponding to a beam energy of 11.4 AMeV. The design gradient is 5 MV/m. Novel features of this resonator are a compact design, low peak fields, easy surface processing and high power coupling. After successful tests at Research Instruments (RI) and in Frankfurt the cavity was processed and cleaned at RI and power tests at 4K have been performed at the cryo lab in Frankfurt. In this paper these measurements will be presented.

THP006	A Superconducting 217 MHz CH Cavitiy for the CW Demonstrator at GSI	cavity, solenoid, linac, cryomodule	906
	F.D. Dziuba, M. Amberg, M. Busch, H. Podlech, U. Ratzinger IAP, Frankfurt am Main, Germany M. Amberg, K. Aulenbacher, W.A. Barth, V. Gettmann, S. Mickat HIM, Mainz, Germany K. Aulenbacher IKP, Mainz, Germany W.A. Barth, S. Mickat GSI, Darmstadt, Germany
	Funding: Work supported by HIM, GSI, BMBF Contr. No. 05P12RFRBL For a competitive production of new Super Heavy Elements (SHE) in the future a 7.3 AMeV superconducting (sc) continuous wave (cw) LINAC is planned at GSI. Currently, a cw demonstrator is going to be built up. The demonstrator consists of a sc 217 MHz Crossbar-H-mode (CH) cavity and two sc 9.5 T solenoids mounted in a horizontal cryostat. One major goal of the demonstrator project is to show the operation ability of sc CH cavity technology under a realistic accelerator environment. After first rf and cold tests the demonstrator will be tested with beam delivered by the GSI High Charge State Injector (HLI) in 2014.

THP035	Production of a 1.3 GHz Niobium 9-cell TRIUMF-PAVAC Cavity for the ARIEL Project	cavity, TRIUMF, monitoring, SRF	978
	V. Zvyagintsev, B. Amini, P.R. Harmer, P. Kolb, R.E. Laxdal, Y. Ma, B.S. Waraich, Z.Y. Yao TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada R. Edinger, M.C. Leustean, R. Singh PAVAC, Richmond, B.C., Canada
	A nine-cell 1.3 GHz superconducting niobium cavity has been fabricated for the ARIEL project at TRIUMF. The cavity is intended to accelerate a beam current of 10 mA at an accelerating gradient of 10 MV/m. The beam loaded RF power of 100 kW is supplied through two opposed fundamental power couplers. The electromagnetic design was done by TRIUMF. The cavity final design and fabrication procedure have been developed in collaboration between TRIUMF and PAVAC Industries Inc. Several innovations in the cavity fabrication process were developed at PAVAC. Since the most important weld is at the equator this weld is done first to form a ‘smart-bell’ as the basic unit as opposed to welding first at the iris to form ‘dumb-bell’ units. Each half cell is pressed with a male die into a plastic forming surface to produce half-cells with less shape distortion and material dislocations. The cavity fabrication sequence including the frequency tuning steps and RF frequency modelling methods will be discussed.

FRIOB01	SRF Cavities for Future Ion Linacs	cavity, cryomodule, linac, SRF	1183
	Z.A. Conway, G.L. Cherry, S.M. Gerbick, M. Kedzie, M.P. Kelly, S.H. Kim, S.V. Kutsaev, R.C. Murphy, B. Mustapha, P.N. Ostroumov, T. Reid ANL, Argonne, USA
	There is considerable interest worldwide in the applications of high-intensity (>5 mA) high-energy (>200 MeV) ion accelerators and the research which could be done with these machines. This presentation will present results of the three year ANL study funded specifically to make possible substantial reductions in the size and cost for future ion linacs in the region beta < 0.5. Applications include basic research, medical isotope production, and accelerator driven systems. High-performance low-beta resonators are key components of all of these machines. Recent 72.75 MHz, β = 0.077, quarter-wave resonator cold test results, designs and their impact on next generation ion accelerators are discussed. Peak fields in excess of 166 mT and 117 MV/m have been achieved and future work to improve upon this will be discussed.
	Slides FRIOB01 [3.833 MB]

Paper

Title

Other Keywords

Page

MOIOA01

The FRIB Project at MSU

cavity, cryomodule, linac, operation

1

M. Leitner, B. Bird, F. Casagrande, S. Chouhan, C. Compton, J.L. Crisp, K. Elliott, A. Facco, A.D. Fox, M. Hodek, M.J. Johnson, G. Kiupel, I.M. Malloch, D. Miller, S.J. Miller, D. Morris, D. Norton, R. Oweiss, J.P. Ozelis, J. Popielarski, L. Popielarski, A.P. Rauch, R.J. Rose, K. Saito, M. Shuptar, N.R. Usher, G.J. Velianoff, D.R. Victory, J. Wei, J. Whitaker, K. Witgen, T. Xu, Y. Xu, O. Yair, S. Zhao
FRIB, East Lansing, 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 Facility for Rare Isotope Beams (FRIB) is ready to start construction. The facility will utilize a high-intensity, heavy-ion driver linac to provide stable ion beams from protons to uranium up to energies of >200 MeV/u and at a beam power of up to 400 kW. The superconducting cw linac consists of 330 individual low-beta (β = 0.041, 0.085, 0.29, and 0.53 at 80.5 MHz and 322 MHz) cavities in 49 cryomodules operating at 2 K. This paper discusses the current development status of the project with emphasis on the linac SRF acquisition. SRF coldmass and cryomodule component designs are briefly summarized. A SRF production facility, currently under construction, is described.

Slides MOIOA01 [9.804 MB]

MOIOA02

Status and Challenges of Spiral2 SRF Linac

cryomodule, linac, cavity, vacuum

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]

MOIOA05

SRF in Heavy Ions Projects

cavity, linac, heavy-ion, cryomodule

30

D. Jeon
IBS, Daejeon, Republic of Korea

SRF technologies are widely applied to heavy ion accelerator projects in the world such as the RAON, C-ADS, HIAF, FRIB, SPIRAL2, ISAC-II, HIE-ISOLDE etc. In this talk, status report, design choices and SRF challenges met in heavy ion machines are presented.

Slides MOIOA05 [10.228 MB]

MOP008

SUPERCONDUCTING LINAC FOR THE RISP

linac, cavity, cryomodule, proton

89

H.J. Kim, H.J. Cha, M.O. Hyun, H.J. Jang, D. Jeon, J.D. Joo, M.J. Joung, H.C. Jung, Y. Jung, Y. Kim, M. Lee, G.-T. Park
IBS, Daejeon, Republic of Korea

The RISP (Rare Isotope Science Project) accelerator has been planned to study heavy ion of nuclear, material and medical science at the Institute for Basic Science (IBS). It can deliver ions from proton to Uranium. The facility consists of three superconducting linacs of which superconducting cavities are independently phased. Requirement of the linac design is especially high for acceleration of multiple charge beams. In this paper, we present the RISP linac design, the superconducting cavity, and cryomodule.

MOP012

Completion of the Superconducting Heavy Ion Linac at Inter-University Accelerator Centre

linac, operation, electronics, controls

103

A. Rai, R. Ahuja, J. Antony, S. Babu, J. Chacko, G.K. Chaudhari, A. Chaudhary, T.S. Datta, R.N. Dutt, S. Ghosh, R. Joshi, D. Kanjilal, S. Kar, J. Karmakar, M. Kumar, R. Kumar, D.S. Mathuria, R. Mehta, K.K. Mistri, A. Pandey, P. Patra, P.N. Prakash, A. Roy, J. Sacharias, B.K. Sahu, A. Sarkar, S.S.K. Sonti, S. K. Suman, J. Zacharias
IUAC, New Delhi, India

The Superconducting heavy ion Linac at Inter University Accelerator Centre (IUAC), New Delhi has been delivering accelerated ion beams to the users since 2009 *. Initially the first accelerating module, housing eight Quarter Wave Resonators (QWR’s), became operational together with the Superbuncher having one and the Rebuncher having two QWR’s, respectively. In the subsequent years, the remaining two modules have been installed and commissioned. The complete Linac was operated recently and several ion beams were delivered for scheduled experiments. The maximum energy gain was 8 MeV per charge state. Operational highlights include successful operation of four resonators in the third module with Piezo based ** mechanical tuning, implementation of remote phase locking for all resonators in three modules, development of a scheme for auto locking of resonators and testing of a capacitive pickup as a beam diagnostic element. Details will be presented vis-à-vis the problems encountered and the future course of action.
* A. Rai et. al., Proc. of SRF2009 Sept. 20–25, 2009, Berlin, Germany, page 244.
** B.K.Sahu et. al., Proc. of IPAC 2010, Kyoto Japan, page 2920.

MOP021

Conceptual Design of SC Linac for RIBF-Upgrade Plan

linac, cryomodule, cavity, quadrupole

137

K. Yamada, O. Kamigaito, N. Sakamoto, K. Suda
RIKEN Nishina Center, Wako, Japan

For the intensity upgrade of very-heavy ions such as 238U and 124Xe at the RIKEN RI-Beam Factory (RIBF), a design study of new SC linac injector has started on. In the RIBF, the very-heavy ions are accelerated in a cascade of the injector linac (RILAC2), the RIKEN ring cyclotron (RRC), the fixed-frequency ring cyclotron (fRC), the intermediate-stage ring cyclotron (IRC), and the world's first superconducting ring cyclotron (SRC). We plan to substitute the SC linac for the RRC with respect to the very heavy ions, and to boost up the energy of ions with mass-to-charge ratio of 7 from 1.4 MeV/u to 11 MeV/u in the cw mode. The SC cavity is assumed to be a two gap QWR with an rf frequency of 73 MHz, that is twice the rf frequency of IRC and SRC. The cell parameters and number of cavity are determined by calculating the energy gain of synchronous ion by taking the rf phase at the center of gap into account. The transverse motion is calculated by the transfer matrix method and several types of lattice are studied. This contribution reports the progress of design study for the SC linac.

MOP059

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

cavity, vacuum, SRF, 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.

TUP075

Design and Commissioning Status of New Cylindrical HiPIMS Nb Coating System for SRF Cavities

cavity, niobium, cathode, SRF

617

H.L. Phillips, K. Macha, A-M. Valente-Feliciano
JLAB, Newport News, Virginia, USA

Funding: † Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
For the past 19 years Jefferson Lab has sustained a program studying niobium films deposited on small samples in order to develop an understanding of the correlation between deposition parameters, film micro-structure, and RF performance. A new cavity deposition system employing a cylindrical cathode using the HiPIMS technique has been developed to apply this work to cylindrical cavities. The status of this system will be presented.

TUP079

ECR Nb Films Grown on Amorphous and Crystalline Cu Substrates: Influence of Ion Energy

ECR, SRF, interface, electron

631

A-M. Valente-Feliciano, G.V. Eremeev, H.L. Phillips, C.E. Reece
JLAB, Newport News, Virginia, USA
C. Cao
Illinois Institute of Technology, Chicago, IL, USA
Th. Proslier
ANL, Argonne, USA
J.K. Spradlin
JLab, Newport News, Virginia, USA
T. Tao
UIC, Chicago, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
In the pursuit of niobium (Nb) films with similar performance with the commonly used bulk Nb surfaces for Superconducting RF (SRF) applications, significant progress has been made with the development of energetic condensation deposition techniques. Using energetic condensation of ions extracted from plasma generated by Electron Cyclotron Resonance, it has been demonstrated that Nb films with good structural properties and RRR comparable to bulk values can be produced on metallic substrates. The controlled incoming ion energy enables a number of processes such as desorption of adsorbed species, enhanced mobility of surface atoms and sub-implantation of impinging ions, thus producing improved film structures at lower process temperatures. Particular attention is given to the nucleation conditions to create a favorable template for growing the final surface exposed to SRF fields. The influence of the deposition energy for both hetero-epitaxial and fiber growth modes on copper substrates is investigated with the characterization of the film surface, structure, superconducting properties and RF performance.

TUP082

Materials Analysis of CED Nb Films Being Coated on Bulk Nb Single Cell SRF Cavities

cavity, SRF, HOM, cryogenics

638

X. Zhao, C.E. Reece
JLab, Newport News, Virginia, USA
G. Ciovati
Jefferson Lab, Newport News, Virginia, USA
I. Irfan, C. James, M. Krishnan
AASC, San Leandro, California, USA
A.D. Palczewski
JLAB, Newport News, Virginia, USA

Funding: This research is supported at AASC by DOE via Grant No. DE-FG02-08ER85162 and Grant No. DE-SC0004994 and by Jefferson Science Associates, LLC under U.S. DOE Contract No. DEAC05- 06OR23177
This study is an on-going research on depositing a Nb film on the internal wall of bulk Nb single cell SRF cavities, via an coaxial energetic condensation (CED) facility at AASC company. The motivation is to firstly create a homoepitaxy-like Nb/Nb film in a scale of a ~1.5GHz RF single cell cavity. Next, through SRF measurement and materials analysis, it might reveal the baseline properties of the CED-type homoepitaxy Nb films. Such knowledge of Nb-Nb homo-epitaxy is useful to create future realistic SRF cavity film coatings, such as hetero-epitaxy Nb/Cu Films, or template-layer-mitigated Nb films. One large-grain, and three fine grain bulk Nb cavity were coated. They went through cryogenic RF measurement. Preliminary results show that the Q0 of a Nb film at 2 K and low rf field, produced by CED, could be close to that of the pre-coated bulk Nb surface (being CBP'ed plus a light EP); but the quality drops rapidly for increasing rf field. We are investigating if the severe Q0-slope is caused by hydrogen incorporation before deposition, or is determined by some structural defects during Nb film growth.

TUP093

Field Emitter Current Conditioning on Nb Single Crystals with Different Roughness due to Varying EP/BCP Ratio

site, gun, controls, damping

686

S. Lagotzky, G. Müller
Bergische Universität Wuppertal, Wuppertal, Germany
P. Kneisel
JLAB, Newport News, Virginia, USA

Funding: Funding by the BMBF project 05H12PX6
Enhanced field emission (EFE) from particulate contaminations and surface irregularities is one of the main field limitations of the superconducting Nb cavities required for XFEL and ILC. While the number density of particulate emitters can be reduced by dry ice cleaning (DIC) and clean room assembly, the optimum choice of crystallinity and polishing are still under discussion [1]. For the future ILC cavities, large or even single crystal Nb with a combination of BCP and EP is considered. Therefore, we have systematically investigated the EFE of single crystal Nb samples which got the same total polishing depth 136-138 μm but a different EP/BCP ratio (5.80, 2.40, 0.73, 0.15) and DIC by means of correlated optical/AFM profilometry, field emission scaning microscopy (FESM) and high-resolution SEM. Depending on the surface roughness (Ra < 200 nm), field enhancement factors b of 12 – 42 and emitting areas S up to 0.1 μm² were obtained. High current conditioning (μA - mA) of these emitters usually resulted in a slight reduction of b (factor < 2) but a strong increase of S. The influence of the surface roughness on the EFE and conditioning of the remaining emitters will be discussed.
[1] Reschke et al., Phys. Rev. ST Accel. Beams 13, 071001-1 (2010)

WEIOA01

HiPIMS: a New Generation of Film Deposition Techniques for SRF Applications

SRF, cavity, plasma, target

754

A-M. Valente-Feliciano
JLAB, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Over the years, Nb/Cu technology, despite its shortcomings due to the commonly used magnetron sputtering, has positioned itself as an alternative route for the future of accelerator superconducting structures. Avenues for the production of thin films tailored for Superconducting RF (SRF) applications are showing promise with recent developments in ionized PVD coating techniques, i.e. vacuum deposition techniques using energetic ions. Among these techniques, High power impulse magnetron sputtering (HiPIMS) is a promising emerging technique which combines magnetron sputtering with a pulsed power approach. This contribution describes the benefits of energetic condensation for SRF films and the characteristics of the HiPIMS technology. It describes the on-going efforts pursued in different institutions to exploit the potential of this technology to produce bulk-like Nb films and go beyond Nb performance with the development of film systems, based on other superconducting materials and multilayer structures.

Slides WEIOA01 [12.446 MB]

WEIOA02

Energetic Condensation Growth of Niobium Films

cavity, lattice, plasma, vacuum

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]

THIOC01

Low Beta Cavity Development for an ATLAS Intensity Upgrade

cavity, cryomodule, niobium, linac

850

M.P. Kelly, Z.A. Conway, S.M. Gerbick, M. Kedzie, S.H. Kim, R.C. Murphy, B. Mustapha, P.N. Ostroumov, T. Reid
ANL, Argonne, USA

The set of seven new 72 MHz quarter wave SC (QWR) cavities has been completed and is being installed in the ATLAS heavy-ion accelerator at Argonne. The aim is to provide at least 17.5 MV accelerating potential with large acceptance and minimal beam losses for high intensity ion beams. The cavity electromagnetic design uses optimizations not used before with QWR including a large taper on both the inner and outer conductors in order to reduce surface fields and make efficient use of space along the beam line. Electropolishing (EP) on the finished cavities with integral helium jacket and no demountable RF joints has been performed, and is the first for any low beta SC cavity. This type of EP, adapted from Argonne systems for the linear collider effort, appears to have a large benefit in terms of the average quench field which range between 103-165 mT for five QWR tested to date. Cavity residual resistances at the proposed operating point of ~70 mT are low, clustering close to a value of ~2nOhm. Additional technical details including the almost exclusive use of wire EDM for niobium fabrication and a new CW 4 kW RF power coupler are presented.

Slides THIOC01 [10.152 MB]

THP003

Cold Measurements on the 325 MHz CH-Cavity

cavity, linac, coupling, operation

896

M. Busch, F.D. Dziuba, H. Podlech, U. Ratzinger
IAP, Frankfurt am Main, Germany
M. Amberg
HIM, Mainz, Germany

Funding: GSI, BMBF Contr. No. 06FY7102, 06FY9089I
At the Institute for Applied Physics (IAP), Frankfurt University, a sc 325 MHz CH-Cavity has been designed and built. This 7-cell cavity has a geometrical beta of 0.16 corresponding to a beam energy of 11.4 AMeV. The design gradient is 5 MV/m. Novel features of this resonator are a compact design, low peak fields, easy surface processing and high power coupling. After successful tests at Research Instruments (RI) and in Frankfurt the cavity was processed and cleaned at RI and power tests at 4K have been performed at the cryo lab in Frankfurt. In this paper these measurements will be presented.

THP006

A Superconducting 217 MHz CH Cavitiy for the CW Demonstrator at GSI

cavity, solenoid, linac, cryomodule

906

F.D. Dziuba, M. Amberg, M. Busch, H. Podlech, U. Ratzinger
IAP, Frankfurt am Main, Germany
M. Amberg, K. Aulenbacher, W.A. Barth, V. Gettmann, S. Mickat
HIM, Mainz, Germany
K. Aulenbacher
IKP, Mainz, Germany
W.A. Barth, S. Mickat
GSI, Darmstadt, Germany

Funding: Work supported by HIM, GSI, BMBF Contr. No. 05P12RFRBL
For a competitive production of new Super Heavy Elements (SHE) in the future a 7.3 AMeV superconducting (sc) continuous wave (cw) LINAC is planned at GSI. Currently, a cw demonstrator is going to be built up. The demonstrator consists of a sc 217 MHz Crossbar-H-mode (CH) cavity and two sc 9.5 T solenoids mounted in a horizontal cryostat. One major goal of the demonstrator project is to show the operation ability of sc CH cavity technology under a realistic accelerator environment. After first rf and cold tests the demonstrator will be tested with beam delivered by the GSI High Charge State Injector (HLI) in 2014.

THP035

Production of a 1.3 GHz Niobium 9-cell TRIUMF-PAVAC Cavity for the ARIEL Project

cavity, TRIUMF, monitoring, SRF

978

V. Zvyagintsev, B. Amini, P.R. Harmer, P. Kolb, R.E. Laxdal, Y. Ma, B.S. Waraich, Z.Y. Yao
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
R. Edinger, M.C. Leustean, R. Singh
PAVAC, Richmond, B.C., Canada

A nine-cell 1.3 GHz superconducting niobium cavity has been fabricated for the ARIEL project at TRIUMF. The cavity is intended to accelerate a beam current of 10 mA at an accelerating gradient of 10 MV/m. The beam loaded RF power of 100 kW is supplied through two opposed fundamental power couplers. The electromagnetic design was done by TRIUMF. The cavity final design and fabrication procedure have been developed in collaboration between TRIUMF and PAVAC Industries Inc. Several innovations in the cavity fabrication process were developed at PAVAC. Since the most important weld is at the equator this weld is done first to form a ‘smart-bell’ as the basic unit as opposed to welding first at the iris to form ‘dumb-bell’ units. Each half cell is pressed with a male die into a plastic forming surface to produce half-cells with less shape distortion and material dislocations. The cavity fabrication sequence including the frequency tuning steps and RF frequency modelling methods will be discussed.

FRIOB01

SRF Cavities for Future Ion Linacs

cavity, cryomodule, linac, SRF

1183

Z.A. Conway, G.L. Cherry, S.M. Gerbick, M. Kedzie, M.P. Kelly, S.H. Kim, S.V. Kutsaev, R.C. Murphy, B. Mustapha, P.N. Ostroumov, T. Reid
ANL, Argonne, USA

There is considerable interest worldwide in the applications of high-intensity (>5 mA) high-energy (>200 MeV) ion accelerators and the research which could be done with these machines. This presentation will present results of the three year ANL study funded specifically to make possible substantial reductions in the size and cost for future ion linacs in the region beta < 0.5. Applications include basic research, medical isotope production, and accelerator driven systems. High-performance low-beta resonators are key components of all of these machines. Recent 72.75 MHz, β = 0.077, quarter-wave resonator cold test results, designs and their impact on next generation ion accelerators are discussed. Peak fields in excess of 166 mT and 117 MV/m have been achieved and future work to improve upon this will be discussed.

Slides FRIOB01 [3.833 MB]