TY  - CONF
AU  - Cravatta, A.T.
AU  - Aderhold, S.
AU  - Arkan, T.T.
AU  - Bafia, D.
AU  - Checchin, M.
AU  - Drury, M.A.
AU  - Gonnella, D.
AU  - Hogan, J.
AU  - Kaluzny, J.A.
AU  - Maniscalco, J.T.
AU  - Nelson, J.
AU  - Porter, R.D.
AU  - Posen, S.
AU  - Vennekate, H.
AU  - Zacarias, L.M.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Multipacting Processing in Cryomodules for LCLS-II and LCLS-II-HE
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - Multipacting (MP) is a phenomenon which can affect stability in particle accelerators and limit performance in superconducting radio frequency cavities. In the TESLA shaped, 1.3 GHz, 9-cell cavities used in the LCLS-II (L2) and LCLS-II-HE (HE) projects, the MP-band (~17-24 MV/m) lies within the required accelerating gradients. For HE, the operating gradient of 20.8 MV/m lies well within the MP-band and cryomodule testing has confirmed that this is an issue. As such, MP processing for the HE cryomodule test program will be discussed. Early results on MP processing in cryomodules installed in the L2 linac will also be presented, demonstrating that the methods used in cryomodule acceptance testing are also successful at conditioning MP in the accelerator and that this processing is preserved in the mid-term.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 259
EP  - 262
KW  - cavity
KW  - cryomodule
KW  - linac
KW  - radiation
KW  - multipactoring
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-MOPMB063
UR  - https://jacow.org/srf2023/papers/mopmb063.pdf
ER  - 

TY  - CONF
AU  - Xiang, R.
AU  - Adolphsen, C.
AU  - Arnold, A.
AU  - Gatzmaga, S.
AU  - Hartung, W.
AU  - Hoffmann, A.
AU  - Kelly, M.P.
AU  - Kim, S.H.
AU  - Konomi, T.K.
AU  - Lewellen, J.W.
AU  - Miller, S.J.
AU  - Murcek, P.
AU  - Petersen, T.B.
AU  - Popielarski, L.
AU  - Saito, K.
AU  - Smedley, J.
AU  - Steinbrück, R.
AU  - Teichert, J.
AU  - Xu, T.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Design of a Cathode Insertion and Transfer System for LCLS-II-HE SRF Gun
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - Superconducting radio frequency photo injectors (SRF gun) offer advantages for operating in continuous wave (CW) mode and generating high-brightness and high-current beams. A new SRF gun is designed as a low emittance photo injector for LCLS-II-HE and a prototype gun is currently being developed under collaboration between SLAC, FRIB, HZDR and ANL. The aim is to demonstrate stable CW operation at a cathode gradient of 30 MV/m. One of the crucial component for successful SRF gun operation is the photocathode system. The new SRF gun will adopt the HZDR-type cathode, which includes a cathode holder fixture (cathode stalk) developed by FRIB and a sophisticated cathode exchange system designed by HZDR. This innovative cathode insertion system ensures accurate, particle-free and warm cathode exchanges. A novel alignment process targets the cathode to the stalk axis without touching cathode plug itself. To commission the prototype gun, metallic cathodes will be used. A specifically designed vacuum system ensures vacuum pressure of 10⁻⁹ mbar for transport of a single cathode from the cleanroom to the gun. Thus maintaining cathode quality.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 267
EP  - 270
KW  - cathode
KW  - gun
KW  - SRF
KW  - insertion
KW  - operation
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-MOPMB067
UR  - https://jacow.org/srf2023/papers/mopmb067.pdf
ER  - 

TY  - CONF
AU  - Maniscalco, J.T.
AU  - Aderhold, S.
AU  - Arkan, T.T.
AU  - Bafia, D.
AU  - Bevins, M.E.
AU  - Checchin, M.
AU  - Cravatta, A.T.
AU  - Gonnella, D.
AU  - Grabowski, A.J.
AU  - Hogan, J.
AU  - Kaluzny, J.A.
AU  - Porter, R.D.
AU  - Posen, S.
AU  - Reece, C.E.
AU  - Vennekate, H.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - LCLS-II-HE Cavity Qualification Testing
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - Acceptance testing of the LCLS-II-HE production cavities is approximately 65% complete. In this report, we present details of the test results, including summaries of the quench fields, intrinsic quality factors, and experience with field emission. We also offer an outlook on the remaining tests to be performed.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 279
EP  - 281
KW  - cavity
KW  - cryomodule
KW  - radiation
KW  - SRF
KW  - accelerating-gradient
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-MOPMB072
UR  - https://jacow.org/srf2023/papers/mopmb072.pdf
ER  - 

TY  - CONF
AU  - White, D.A.
AU  - Checchin, M.
AU  - Gonnella, D.
AU  - Hogan, J.
AU  - Maniscalco, J.T.
AU  - Porter, R.D.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Cryomodule Storage for LCLS-II HE
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - The Linac Coherent Light Source-II High Energy (LCLS-II HE) project will upgrade the superconducting LCLS-II with 23 additional cryomodules, increasing the beam energy from 4 GeV to 8 GeV. Due to the user schedule of the existing linac, Cryomodules arriving at SLAC cannot immediately be installed in the linac. They are scheduled to be stored for up to three years before the 12-month installation window. During this storage period, the risk of damage to Cryomodules prior to installation will be mitigated with procedures and best practices incorporating experience from LCLS-II.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 282
EP  - 285
KW  - cryomodule
KW  - vacuum
KW  - controls
KW  - cavity
KW  - cathode
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-MOPMB074
UR  - https://jacow.org/srf2023/papers/mopmb074.pdf
ER  - 

TY  - CONF
AU  - Porter, R.D.
AU  - Aderhold, S.
AU  - Alsberg, L.E.
AU  - Cravatta, A.T.
AU  - Drury, M.A.
AU  - Gaitan, G.
AU  - Gonnella, D.
AU  - Holzbauer, J.P.
AU  - McCaughan, M.D.
AU  - Nelson, J.
AU  - Neveu, N.R.
AU  - Posen, S.
AU  - Stilin, N.A.
AU  - Wilson, C.M.
AU  - Zacarias, L.M.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Microphonics in the LCLS-II Superconducting Linac
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - The LCLS-II project has installed a new superconducting linac at SLAC that consists of 35 1.3 GHz cryomodules and 2 3.9 GHz cryomodules. The linac will provide a 4 GeV electron beam for generating soft and hard X-ray pulses. Cavity detuning induced by microphonics was a significant design challenge for the LCLS-II cryomodules. Cryomodules were produced that were within the detuning specification (10 Hz for 1.3 GHz cryomodules) on test stands. Here we present first measurements of the microphonics in the installed LCLS-II superconducting linac. Overall, the microphonics in the linac are manageable with 94% of cavities coming within the detune specification. Only two cavities are gradient limited due to microphonics. We identify a leaking cool down valve as the source of microphonics limiting those two cavities.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 302
EP  - 305
KW  - cryomodule
KW  - cavity
KW  - linac
KW  - operation
KW  - vacuum
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-MOPMB081
UR  - https://jacow.org/srf2023/papers/mopmb081.pdf
ER  - 

TY  - CONF
AU  - White, D.A.
AU  - Aderhold, S.
AU  - Coy, R.
AU  - Gonnella, D.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Installation of LCLS-II Cryomodules
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - The Linac Coherent Light Source II (LCLS-II) super-conducting accelerator is fully installed and operational. Cryomodules were designed and manufactured by Fermi National Accelerator Laboratory (FNAL) and Thomas Jefferson National Laboratory (JLab) during 2017-2020. From November 2018 through March 2021, SLAC Na-tional Accelerator Laboratory installed 37 Cryomodules. Full system cooldown was completed in March 2022. Installation processes were optimized at SLAC for best quality, especially during particle-free and UHV assem-bly. These processes and successful Cavity and Cry-omodule manufacturing resulted in installed gradient exceeding design requirements by more than 20%. No statistical variation in field emission onsets or magni-tudes were observed between manufacturing and site testing. This paper summarizes SLAC experience during installation, and relevant testing results.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 324
EP  - 326
KW  - cryomodule
KW  - vacuum
KW  - hardware
KW  - cavity
KW  - MMI
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-MOPMB089
UR  - https://jacow.org/srf2023/papers/mopmb089.pdf
ER  - 

TY  - CONF
AU  - Zacarias, L.M.
AU  - Aderhold, S.
AU  - Cravatta, A.T.
AU  - Drury, M.A.
AU  - Gonnella, D.
AU  - Holzbauer, J.P.
AU  - Maniscalco, J.T.
AU  - McCaughan, M.D.
AU  - Nelson, J.
AU  - Porter, R.D.
AU  - Posen, S.
AU  - Wilson, C.M.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Measuring Q₀ in LCLS-II Cryomodules Using Helium Liquid Level
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - The nitrogen-doped cavities used in the Linac Coherent Light Source II (LCLS-II) cryomodules have shown an unprecedented high Q₀ in vertical and cryomodule testing compared with cavities prepared with standard methods. While demonstration of high Q₀ in the test stand has been achieved, maintaining that performance in the linac is critical to the success of LCLS-II and future accelerator projects. The LCLS-II cryomodules required a novel method of measuring Q₀, due to hardware incompatibilities with existing procedures. Initially developed at Jefferson Lab during cryomodule acceptance testing before being used in the tunnel at SLAC, we use helium liquid level data to estimate the heat generated by cavities. We first establish the relationship between the rate of helium evaporation from known heat loads using electric heaters, and then use that relationship to determine heat from an RF load. Here we present the full procedure along with the development process, lessons learned, and reproducibility while demonstrating for the first time that world record Q₀ can be maintained within the real accelerator environment.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 327
EP  - 331
KW  - cavity
KW  - cryomodule
KW  - linac
KW  - MMI
KW  - SRF
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-MOPMB090
UR  - https://jacow.org/srf2023/papers/mopmb090.pdf
ER  - 

TY  - CONF
AU  - Ristori, L.
AU  - Berrutti, P.
AU  - Castilla, A.
AU  - De Silva, S.U.
AU  - Delayen, J.R.
AU  - Huque, N.A.
AU  - Li, Z.
AU  - Narduzzi, M.
AU  - Ratti, A.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Development and Performance of RFD Crab Cavity Prototypes for HL-LHC AUP
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - The US will be contributing to the HL-LHC upgrade at CERN with the fabrication and qualification of RFD crabbing cavities in the framework of the HL-LHC Accelerator Upgrade Project (AUP) managed by Fermilab. AUP received Critical Decision 3 (CD-3) approval by DOE in December 2020 launching the project into the production phase. The electro-magnetic design of the cavity was inherited from the LHC Accelerator Research Program (LARP) but needed to be revised to meet new project requirements and to prevent issues encountered during beam tests performed at CERN in the R&D phase. Two prototype cavities were manufactured in industry and cold tested. Challenges specific to the RFD cavity were the stringent interface tolerances, the pole symmetry and the higher-order-mode impedance spectrum. Chemical processing and heat treatments were performed initially at FNAL/ANL and are now being transferred to industry for the production phase. HOM dampers are manufactured and validated by JLAB. A summary of cold test results with and without HOM dampers is presented.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 531
EP  - 535
KW  - cavity
KW  - HOM
KW  - impedance
KW  - niobium
KW  - higher-order-mode
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-TUPTB046
UR  - https://jacow.org/srf2023/papers/tuptb046.pdf
ER  - 

TY  - CONF
AU  - Compton, C.
AU  - Elliott, K.
AU  - Hartung, W.
AU  - Hulbert, J.D.
AU  - Kedzie, M.
AU  - Kelly, M.P.
AU  - Kim, S.H.
AU  - Konomi, T.
AU  - Lewellen, J.W.
AU  - Miller, S.J.
AU  - Patil, M.S.
AU  - Petersen, T.B.
AU  - Popielarski, J.T.
AU  - Popielarski, L.
AU  - Saito, K.
AU  - Smedley, J.
AU  - Witgen, K.
AU  - Xu, T.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Fabrication Efforts Toward a Superconducting Rf Photo-Infector Quarter-Wave Cavity for Use in Low Emittance Injector Applications
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - The Facility for Rare Isotope Beams (FRIB), in collaboration with Argonne National Laboratory (ANL) and Helmholtz-Zentrum Dresden-Rossendorf (HDZR), is working on the design and fabrication of a photo-injector cryomodule; suitable for operation as part of accelerator systems at SLAC National Accelerator Laboratory. Project scope requires the fabrication of two 185.7 MHz superconducting, quarter-wave resonators (QWR) based, injector cavities. Cavity fabrication will be completed at FRIB with contracted vendors supporting subcomponent fabrication and electron-beam welding. Fabrication will use poly-crystalline and large grain RRR niobium materials. The current status of cavity fabrication will be presented including material procurement, prototype forming, and electron-beam welding development.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 568
EP  - 572
KW  - cavity
KW  - niobium
KW  - SRF
KW  - cryomodule
KW  - gun
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-TUPTB063
UR  - https://jacow.org/srf2023/papers/tuptb063.pdf
ER  - 

TY  - CONF
AU  - Li, Z.
AU  - De Silva, S.U.
AU  - Delayen, J.R.
AU  - Rimmer, R.A.
AU  - Wu, Q.
AU  - Xiao, B.P.
AU  - Xu, W.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - EIC 197 MHz Crab Cavity RF Optimization
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - Crab cavities, operating at 197 MHz and 394 MHz respectively, will be used to compensate the loss of luminosity due to a 25 mrad crossing angle at the interaction point in the Electron Ion Collider (EIC). Both crab cavities are of the RF Dipole (RFD) shape. To meet the machine design requirements, there are a few important cavity design considerations that need to be addressed. First, to achieve stable cavity operation at the design voltages, cavity geometry details must be optimized to suppress potential multipacting. Incorporating strong HOM damping in the cavity design is required for the beam stability and quality. Furthermore, due to the finite pole width, the multipole fields, especially the sextupole and the decapole terms, need to be minimized to maintain an acceptable beam dynamic aperture. This paper will present the RF optimization details of the 197 MHz cavity.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 584
EP  - 588
KW  - cavity
KW  - HOM
KW  - multipactoring
KW  - GUI
KW  - impedance
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-TUPTB068
UR  - https://jacow.org/srf2023/papers/tuptb068.pdf
ER  - 

TY  - CONF
AU  - Konomi, T.K.
AU  - Adolphsen, C.
AU  - Gatzmaga, S.
AU  - Hartung, W.
AU  - Kelly, M.P.
AU  - Kim, S.H.
AU  - Lewellen, J.W.
AU  - Miller, S.J.
AU  - Morris, D.G.
AU  - Murcek, P.
AU  - Petersen, T.B.
AU  - Saito, K.
AU  - Smedley, J.
AU  - Taylor, A.T.
AU  - Xiang, R.
AU  - Xiao, L.
AU  - Xu, T.
AU  - Yin, Z.Y.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Design and Tests of a Cathode Stalk for the LCLS-II-HE Low Emittance Injector SRF Gun
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - A SRF gun can operate CW with a high gradient and ultra-low vacuum for high-quantum efficiency, low MTE photocathodes, useful features for delivery of high-brightness, high-repetition-rate beams. For these reasons, an SRF gun based photoinjector was chosen for a proposed Low Emittance Injector addition to the LCLS-II-HE facility, which will operate CW with bunch rates up to 1 MHz. For this injector, a prototype 185.7 MHz QWR gun is being developed in a collaborative effort among FRIB, HZDR, ANL and SLAC, with the goal of achieving a photocathode gradient of at least 30 MV/m. The photocathode is held by a coaxial fixture (cathode stalk) for thermal isolation from the cavity body. The system must allow for precise alignment of the photocathode, particle-free photocathode exchange, cryogenic (55-70 K) or warm (273-300 K) photocathode operating temperatures, and DC biasing to inhibit multipacting. A prototype cathode stalk has been built and bench tests are underway to validate the design. Measurements include RF power dissipation, DC bias hold-off, multipacting suppression and heat transfer effectiveness. This paper describes the cathode stalk design and the test results.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 589
EP  - 592
KW  - cathode
KW  - gun
KW  - SRF
KW  - emittance
KW  - operation
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-TUPTB069
UR  - https://jacow.org/srf2023/papers/tuptb069.pdf
ER  - 

TY  - CONF
AU  - Verboncoeur, N.M.
AU  - Holic, A.T.
AU  - Liepe, M.
AU  - Oseroff, T.E.
AU  - Porter, R.D.
AU  - Sears, J.
AU  - Shpani, L.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Update on Cornell High Pulsed Power Sample Host Cavity
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - The Cornell High Pulsed Power Sample Host Cavity (CHPPSHC) is designed to measure the temperature-dependent superheating fields of future SRF materials and thereby gain insights into the ultimate limits of their performance. Theoretical estimation of the superheating fields of SRF materials is challenging and mostly has been done for temperatures near the critical temperature or in the infinite kappa limit. Experimental data currently available is incomplete, and often impacted by material defects and their resulting thermal heating, preventing finding the fundamental limits of theses materials. The CHPPSHC system allows reaching RF fields in excess of half a Tesla within microseconds on material samples by utilizing high pulsed power, thereby outrunning thermal effects. We are principally interested in the superheating field of Nb₃Sn, a material of interest for the SRF community, and present here the current fabrication and assembly status of the CHPPSHC as well as early results.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 841
EP  - 846
KW  - cavity
KW  - SRF
KW  - coupling
KW  - pulsed-power
KW  - simulation
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-WEPWB108
UR  - https://jacow.org/srf2023/papers/wepwb108.pdf
ER  - 

TY  - CONF
AU  - Maniscalco, J.T.
AU  - Aderhold, S.
AU  - Arkan, T.T.
AU  - Bafia, D.
AU  - Bevins, M.E.
AU  - Checchin, M.
AU  - Gonnella, D.
AU  - Grabowski, A.J.
AU  - Hogan, J.
AU  - Kaluzny, J.A.
AU  - Porter, R.D.
AU  - Posen, S.
AU  - Reece, C.E.
AU  - Savransky, D.
AU  - Vennekate, H.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Flux Expulsion Testing for LCLS-II-HE Cavity Production
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - Nitrogen-doped niobium SRF cavities are sensitive to trapped magnetic flux, which decreases the cavity intrinsic Q₀. Prior experimental results have shown that heat treatments to 900°C and higher can result in stronger flux expulsion during cooldown; the precise temperature required tends to vary by vendor lot/ingot of the niobium material used in the cavity cells. For LCLS-II-HE, to ensure sufficient flux expulsion in all cavities, we built and tested single-cell cavities to determine this required temperature for each vendor lot of niobium material to be used in cavity cells. In this report, we present the results of the single-cell flux expulsion testing and the Q₀ of the nine-cell cavities built using the characterized vendor lots. We discuss mixing material from different vendor lots, examine the lessons learned, and finally present an outlook on possible refinements to the single-cell technique.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 876
EP  - 879
KW  - cavity
KW  - cryomodule
KW  - niobium
KW  - SRF
KW  - ECR
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-WEPWB120
UR  - https://jacow.org/srf2023/papers/wepwb120.pdf
ER  - 

TY  - CONF
AU  - Miller, S.J.
AU  - Adolphsen, C.
AU  - Al-Mahmoud, Y.
AU  - Arnold, A.
AU  - Chang, W.
AU  - Choi, Y.
AU  - Compton, C.
AU  - Coy, R.
AU  - Du, X.J.
AU  - Elliott, K.
AU  - Gatzmaga, S.
AU  - Hartung, W.
AU  - Hulbert, J.D.
AU  - Ji, F.
AU  - Kelly, M.P.
AU  - Kim, S.H.
AU  - Konomi, T.
AU  - Lewellen, J.W.
AU  - Morris, D.G.
AU  - Murcek, P.
AU  - Murphy, M.J.
AU  - Patil, M.S.
AU  - Petersen, T.B.
AU  - Piot, P.
AU  - Popielarski, L.
AU  - Saito, K.
AU  - Smedley, J.
AU  - Taylor, A.
AU  - Teichert, J.
AU  - Tousignant, B.P.
AU  - Wei, J.
AU  - Wenstrom, J.D.
AU  - Witgen, K.
AU  - Xiang, R.
AU  - Xiao, L.
AU  - Xu, T.
ED  - Saito, Kenji
ED  - Xu, Ting
ED  - Sakamoto, Naruhiko
ED  - Schaa, Volker R.W.
ED  - Thomas, Paul W.
TI  - Status of the SLAC/MSU SRF Gun Development Project
J2  - Proc. of SRF2023, Grand Rapids, MI, USA, 25-30 June 2023
CY  - Grand Rapids, MI, USA
T2  - International Conference on RF Superconductivity
T3  - 21
LA  - english
AB  - The Linac Coherent Light Source II High Energy (LCLS-II-HE) Project at SLAC includes the construction of a low-emittance injector (LEI) and a superconducting quarter-wave resonator (QWR) at 185.7 MHz. Several alternatives to a superconducting radio frequency (SRF) QWR gun were considered for the LEI, including nor-mal-conducting RF guns evolved from the LCLS-II gun design. Compared to normal-conducting designs, the combination of an intrinsically outstanding vacuum environment (for cathode lifetime), and the potential for a larger ultimate performance envelope, led to the deci-sion to pursue development of the QWR-SRF gun. A prototype gun is currently being designed and fabricated at the Facility for Rare Isotope Beams (FRIB) at Michi-gan State University (MSU). This paper presents perfor-mance goals for the new gun design, an overview of the prototype development effort, status, and future plans including fabrication.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 1003
EP  - 1010
KW  - cryomodule
KW  - SRF
KW  - cathode
KW  - cavity
KW  - alignment
DA  - 2023/09
PY  - 2023
SN  - 2673-5504
SN  - 978-3-95450-234-9
DO  - doi:10.18429/JACoW-SRF2023-FRIBA07
UR  - https://jacow.org/srf2023/papers/friba07.pdf
ER  -