SRF2023 - List of Authors (Konomi, T.)

Paper	Title	Page
MOIAA01	FRIB Transition to User Operations, Power Ramp Up, and Upgrade Perspectives	1
	J. Wei, H. Ao, B. Arend, S. Beher, G. Bollen, N.K. Bultman, F. Casagrande, W. Chang, Y. Choi, S. Cogan, C. Compton, M. Cortesi, J.C. Curtin, K.D. Davidson, X.J. Du, K. Elliott, B. Ewert, A. Facco, A. Fila, K. Fukushima, V. Ganni, A. Ganshyn, T.N. Ginter, T. Glasmacher, J.-W. Guo, Y. Hao, W. Hartung, N.M. Hasan, M. Hausmann, K. Holland, H.-C. Hseuh, M. Ikegami, D.D. Jager, S. Jones, N. Joseph, T. Kanemura, S.H. Kim, C. Knowles, T. Konomi, B.R. Kortum, E. Kwan, T. Lange, M. Larmann, T.L. Larter, K. Laturkar, R.E. Laxdal, J. LeTourneau, Z. Li, S.M. Lidia, G. Machicoane, C. Magsig, P.E. Manwiller, F. Marti, T. Maruta, E.S. Metzgar, S.J. Miller, Y. Momozaki, D.G. Morris, M. Mugerian, I.N. Nesterenko, C. Nguyen, P.N. Ostroumov, M.S. Patil, A.S. Plastun, L. Popielarski, M. Portillo, J. Priller, X. Rao, M.A. Reaume, K. Saito, B.M. Sherrill, M.K. Smith, J. Song, M. Steiner, A. Stolz, O. Tarasov, B.P. Tousignant, R. Walker, X. Wang, J.D. Wenstrom, G. West, K. Witgen, M. Wright, T. Xu, Y. Yamazaki, T. Zhang, Q. Zhao, S. Zhao FRIB, East Lansing, Michigan, USA K. Hosoyama KEK, Ibaraki, Japan P. Hurh Fermilab, Batavia, Illinois, USA M.P. Kelly, Y. Momozaki ANL, Lemont, Illinois, USA R.E. Laxdal TRIUMF, Vancouver, Canada S.O. Prestemon LBNL, Berkeley, California, USA M. Wiseman JLab, Newport News, Virginia, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. After project completion on scope, on cost, and ahead of schedule, the Facility for Rare Isotope Beams began operations for scientific users in May of 2022. During the first 12 months of user operations, the FRIB accelerator complex delivered 5250 beam hours, including 1528 hours to nine science experiments conducted with primary beams of 36Ar, 48Ca, 70Zn, 82Se, 124Xe, and 198Pt at beam energies >200 MeV/u; 2724 hours for beam developments, studies, and tuning; and 998 hours to industrial users and non-scientific programs using the FRIB Single Event Effect (FSEE) beam line. The ramp-up to a beam power of 400 kW is planned over a six-year period; 1 kW was delivered for initial user runs from in 2022, and 5 kW was delivered as of February 2023. Upgrade plans include doubling the primary-beam energy to 400 MeV/nucleon for enhanced discovery potential (¿FRIB 400¿). This talk reports on FRIB status and progress since SRF2021, emphasizing lessons learned during the transition from beam commissioning to machine operations, challenges and resolutions for the power ramp-up, progress with accelerator improvements, and R&D for the energy upgrade.
	Slides MOIAA01 [7.037 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOIAA01
About •	Received ※ 20 June 2023 — Revised ※ 26 June 2023 — Accepted ※ 03 July 2023 — Issue date ※ 19 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB027	Successful Superheating Field Formulas from an Intuitive Model	151
	K. Saito, T. Konomi FRIB, East Lansing, Michigan, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science DE-S0000661 and the National Science Foundation under Cooperative Agreement PHY-1102511 To date, many theoretical formulas for superheating field on SRF cavity are already proposed based rather complicated calculations. This paper proposes the formulas by a very intuitive simple model: energy balance between RF magnetic energy and superconducting condensed one, and a condition of vanishing the mirror vortex line image. The penetration of a single vortex determines the superheating field for a type II superconductor. On the other hand, for type I superconductors, the surface flux penetration determines it. The formula fits very well quantitatively the results of niobium cavity and Nb₃Sn one. In addition, it gives a nice guideline for new material beyond niobium. male, senior
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB027
About •	Received ※ 23 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 15 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB063	Fabrication Efforts Toward a Superconducting Rf Photo-Infector Quarter-Wave Cavity for Use in Low Emittance Injector Applications	568
	C. Compton NSCL, East Lansing, Michigan, USA K. Elliott, W. Hartung, J.D. Hulbert, S.H. Kim, T. Konomi, S.J. Miller, M.S. Patil, J.T. Popielarski, L. Popielarski, K. Saito, K. Witgen, T. Xu FRIB, East Lansing, Michigan, USA M. Kedzie, M.P. Kelly, T.B. Petersen ANL, Lemont, Illinois, USA J.W. Lewellen, J. Smedley SLAC, Menlo Park, California, USA
	Funding: * Work supported by the Department of Energy Contract DE-AC02- 76SF00515 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.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB063
About •	Received ※ 17 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 21 August 2023 — Issue date ※ 21 August 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWB113	Evaluation of Photo-Cathode Port Multipacting in the SRF Photo-Injector Cryomodule for the LCLS-II High-Energy Upgrade	859
SUSPB032	use link to see paper's listing under its alternate paper code
	Z.Y. Yin, W. Hartung, S.H. Kim, T. Konomi, T. Xu FRIB, East Lansing, Michigan, USA
	The high-energy upgrade of the Linac Coherent Light Source (LCLS-II-HE) will increase the photon energy and brightness. A low-emittance injector (LEI) was proposed to increase the photon flux for high X-ray energies. FRIB, HZDR, Argonne, and SLAC are developing a 185.7 MHz superconducting radio-frequency photo-injector (SRF-PI) cryomodule for the LEI. The photo-cathode system requirements are challenging, as cathodes must be maintained at the desired temperature, precisely aligned, and operated without multipacting (MP); to avoid field emission, cathode exchange must be particulate-free. A support stalk has been designed to hold the cathode in position under these requirements. A DC bias is used to inhibit MP. We simulated MP for various surface conditions and bias levels. An RF/DC test was developed to evaluate the cathode stalk performance as a subsystem and to identify and correct issues before assembly into the full cryomodule. The RF/DC test makes use of a resonant coaxial line to generate an RF magnetic field similar to that of the cathode-in-SRF-PI-cavity case. High-power test results will be presented and compared to the MP simulations. * Work supported by the Department of Energy Contract DE-AC02-76SF00515
	Poster WEPWB113 [1.410 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB113
About •	Received ※ 20 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 26 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THIXA01	Investigation of Plasma Processing for Coaxial Resonators	960
	W. Hartung, W. Chang, K. Elliott, S.H. Kim, T. Konomi, K. Saito, P.R. Tutt, T. Xu FRIB, East Lansing, Michigan, USA
	Plasma processing has been investigated by several facilities as a method to mitigate degradation of SRF cavity performance. It provides an alternative to removal and disassembly of cryomodules for refurbishment of each cavity via repeat etching and rinsing. Promising results have been obtained by several groups. Studies of plasma processing for quarter-wave resonators (QWRs) and half-wave resonators (HWRs) were undertaken at FRIB, where a total of 324 such resonators are presently in operation. Plasma ignition and optimization measurements were done with room-temperature-matched input couplers. Plasma cleaning tests were done on several QWRs using the fundamental power coupler (FPC) to drive the plasma. We investigated the usefulness of higher-order modes (HOMs) to drive the plasma. HOMs allow for less mismatch at the FPC and hence lower field in the coupler relative to the cavity. Before-and-after cold tests showed a significant reduction in field emission X-rays with judicious application of plasma processing.
	Slides THIXA01 [2.060 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-THIXA01
About •	Received ※ 01 September 2023 — Accepted ※ 02 September 2023 — Issue date ※ 02 September 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRIBA05	Automation of FRIB SRF Cavities and SC Solenoids Turn-on/off	999
	W. Chang, Y. Choi, X.J. Du, W. Hartung, S.H. Kim, T. Konomi, S.R. Kunjir, H. Nguyen, K. Saito, T. Xu, S. Zhao FRIB, East Lansing, Michigan, USA A. Facco INFN/LNL, Legnaro (PD), Italy
	The superconducting driver Linac for the Facility for Rare Isotope Beams (FRIB) is a heavy ion accelerator that accelerate ions to 200 MeV per nucleon. The Linac has 46 cryomodules that contain 324 superconducting radio frequency (SRF) cavities and 69 superconducting (SC) solenoid packages. For operation of all cryomodules with high efficiency and reliability, automation for SRF cavity and SC solenoid fast turn-on/off is essentially. Based on cryomodule commissioning results and expert experience, all manual cavity and solenoid turn-on/off procedures and steps have been replaced by automatic programs for FRIB linac operation. This allows the operators to turn the systems on and off without expert-level training. Automation reduces the risk of human error, speeds up beam recovery after user access to experimental areas, and increases beam availability. The cavity turn-on procedure makes sure that the cavity can operate at low field with expected read backs, ramps up the field, and makes sure that the RF amplitude and phase are stable. The design, implementation, and operating experience with automation will be presented.
	Slides FRIBA05 [3.503 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-FRIBA05
About •	Received ※ 29 June 2023 — Revised ※ 16 August 2023 — Accepted ※ 21 August 2023 — Issue date ※ 21 August 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRIBA07	Status of the SLAC/MSU SRF Gun Development Project	1003
	S.J. Miller, Y. Al-Mahmoud, W. Chang, Y. Choi, C. Compton, X.J. Du, K. Elliott, W. Hartung, J.D. Hulbert, S.H. Kim, T. Konomi, D.G. Morris, M.S. Patil, L. Popielarski, K. Saito, A. Taylor, B.P. Tousignant, J. Wei, J.D. Wenstrom, K. Witgen, T. Xu FRIB, East Lansing, Michigan, USA C. Adolphsen, R. Coy, F. Ji, M.J. Murphy, J. Smedley, L. Xiao SLAC, Menlo Park, California, USA A. Arnold, S. Gatzmaga, P. Murcek, J. Teichert, R. Xiang HZDR, Dresden, Germany M.P. Kelly, T.B. Petersen, P. Piot ANL, Lemont, Illinois, USA J.W. Lewellen LANL, Los Alamos, New Mexico, USA
	Funding: Work supported by the Department of Energy under Contract DE-AC02-76SF00515 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.
	Slides FRIBA07 [9.655 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-FRIBA07
About •	Received ※ 15 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 11 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB049	Horizontal Test Results of 1.3 GHz Superconducting RF Gun #2 at KEK	540
	T. Konomi, K. Hara, Y. Honda, K. Hosoyama, H. Inoue, E. Kako, Y. Kondo, M. Masuzawa, M. Omet, T. Takatomi, A. Terashima, K. Tsuchiya, R. Ueki, K. Umemori, X. Wang KEK, Ibaraki, Japan
	Superconducting radio-frequency (SRF) electron guns are attractive for delivery of beams at a high bunch repetition rate with a high accelerating field. KEK has been developing the SRF gun to demonstrate basic performance. The SRF gun consists of 1.3 GHz and 1.5 cell SRF gun cavity and K2CsSb photocathode coated on 2K cathode plug. In the vertical test, the surface peak electric field and the surface peak magnetic field reached to 75 MV/m and 170 mT respectively. The SRF gun was installed to horizontal multipurpose cryostat equipped with a superconducting solenoid, photocathode preparation chamber and beam diagnostic line. The results showed the peak surface electric field degraded to 42 MV/m. We suspect that cavity was contaminated during assembly. In this presentation, we will present the high gradient performance in vertical and horizontal test and individual test for each beam line components.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB049
About •	Received ※ 24 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 15 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

FRIB Transition to User Operations, Power Ramp Up, and Upgrade Perspectives

1

J. Wei, H. Ao, B. Arend, S. Beher, G. Bollen, N.K. Bultman, F. Casagrande, W. Chang, Y. Choi, S. Cogan, C. Compton, M. Cortesi, J.C. Curtin, K.D. Davidson, X.J. Du, K. Elliott, B. Ewert, A. Facco, A. Fila, K. Fukushima, V. Ganni, A. Ganshyn, T.N. Ginter, T. Glasmacher, J.-W. Guo, Y. Hao, W. Hartung, N.M. Hasan, M. Hausmann, K. Holland, H.-C. Hseuh, M. Ikegami, D.D. Jager, S. Jones, N. Joseph, T. Kanemura, S.H. Kim, C. Knowles, T. Konomi, B.R. Kortum, E. Kwan, T. Lange, M. Larmann, T.L. Larter, K. Laturkar, R.E. Laxdal, J. LeTourneau, Z. Li, S.M. Lidia, G. Machicoane, C. Magsig, P.E. Manwiller, F. Marti, T. Maruta, E.S. Metzgar, S.J. Miller, Y. Momozaki, D.G. Morris, M. Mugerian, I.N. Nesterenko, C. Nguyen, P.N. Ostroumov, M.S. Patil, A.S. Plastun, L. Popielarski, M. Portillo, J. Priller, X. Rao, M.A. Reaume, K. Saito, B.M. Sherrill, M.K. Smith, J. Song, M. Steiner, A. Stolz, O. Tarasov, B.P. Tousignant, R. Walker, X. Wang, J.D. Wenstrom, G. West, K. Witgen, M. Wright, T. Xu, Y. Yamazaki, T. Zhang, Q. Zhao, S. Zhao
FRIB, East Lansing, Michigan, USA
K. Hosoyama
KEK, Ibaraki, Japan
P. Hurh
Fermilab, Batavia, Illinois, USA
M.P. Kelly, Y. Momozaki
ANL, Lemont, Illinois, USA
R.E. Laxdal
TRIUMF, Vancouver, Canada
S.O. Prestemon
LBNL, Berkeley, California, USA
M. Wiseman
JLab, Newport News, Virginia, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
After project completion on scope, on cost, and ahead of schedule, the Facility for Rare Isotope Beams began operations for scientific users in May of 2022. During the first 12 months of user operations, the FRIB accelerator complex delivered 5250 beam hours, including 1528 hours to nine science experiments conducted with primary beams of 36Ar, 48Ca, 70Zn, 82Se, 124Xe, and 198Pt at beam energies >200 MeV/u; 2724 hours for beam developments, studies, and tuning; and 998 hours to industrial users and non-scientific programs using the FRIB Single Event Effect (FSEE) beam line. The ramp-up to a beam power of 400 kW is planned over a six-year period; 1 kW was delivered for initial user runs from in 2022, and 5 kW was delivered as of February 2023. Upgrade plans include doubling the primary-beam energy to 400 MeV/nucleon for enhanced discovery potential (¿FRIB 400¿). This talk reports on FRIB status and progress since SRF2021, emphasizing lessons learned during the transition from beam commissioning to machine operations, challenges and resolutions for the power ramp-up, progress with accelerator improvements, and R&D for the energy upgrade.

Slides MOIAA01 [7.037 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOIAA01

About •

Received ※ 20 June 2023 — Revised ※ 26 June 2023 — Accepted ※ 03 July 2023 — Issue date ※ 19 July 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB027

Successful Superheating Field Formulas from an Intuitive Model

151

K. Saito, T. Konomi
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science DE-S0000661 and the National Science Foundation under Cooperative Agreement PHY-1102511
To date, many theoretical formulas for superheating field on SRF cavity are already proposed based rather complicated calculations. This paper proposes the formulas by a very intuitive simple model: energy balance between RF magnetic energy and superconducting condensed one, and a condition of vanishing the mirror vortex line image. The penetration of a single vortex determines the superheating field for a type II superconductor. On the other hand, for type I superconductors, the surface flux penetration determines it. The formula fits very well quantitatively the results of niobium cavity and Nb₃Sn one. In addition, it gives a nice guideline for new material beyond niobium.
male, senior

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB027

About •

Received ※ 23 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 15 July 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB063

Fabrication Efforts Toward a Superconducting Rf Photo-Infector Quarter-Wave Cavity for Use in Low Emittance Injector Applications

568

C. Compton
NSCL, East Lansing, Michigan, USA
K. Elliott, W. Hartung, J.D. Hulbert, S.H. Kim, T. Konomi, S.J. Miller, M.S. Patil, J.T. Popielarski, L. Popielarski, K. Saito, K. Witgen, T. Xu
FRIB, East Lansing, Michigan, USA
M. Kedzie, M.P. Kelly, T.B. Petersen
ANL, Lemont, Illinois, USA
J.W. Lewellen, J. Smedley
SLAC, Menlo Park, California, USA

Funding: * Work supported by the Department of Energy Contract DE-AC02- 76SF00515
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.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB063

About •

Received ※ 17 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 21 August 2023 — Issue date ※ 21 August 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWB113

Evaluation of Photo-Cathode Port Multipacting in the SRF Photo-Injector Cryomodule for the LCLS-II High-Energy Upgrade

859

SUSPB032

use link to see paper's listing under its alternate paper code

Z.Y. Yin, W. Hartung, S.H. Kim, T. Konomi, T. Xu
FRIB, East Lansing, Michigan, USA

The high-energy upgrade of the Linac Coherent Light Source (LCLS-II-HE) will increase the photon energy and brightness. A low-emittance injector (LEI) was proposed to increase the photon flux for high X-ray energies. FRIB, HZDR, Argonne, and SLAC are developing a 185.7 MHz superconducting radio-frequency photo-injector (SRF-PI) cryomodule for the LEI. The photo-cathode system requirements are challenging, as cathodes must be maintained at the desired temperature, precisely aligned, and operated without multipacting (MP); to avoid field emission, cathode exchange must be particulate-free. A support stalk has been designed to hold the cathode in position under these requirements. A DC bias is used to inhibit MP. We simulated MP for various surface conditions and bias levels. An RF/DC test was developed to evaluate the cathode stalk performance as a subsystem and to identify and correct issues before assembly into the full cryomodule. The RF/DC test makes use of a resonant coaxial line to generate an RF magnetic field similar to that of the cathode-in-SRF-PI-cavity case. High-power test results will be presented and compared to the MP simulations.
* Work supported by the Department of Energy Contract DE-AC02-76SF00515

Poster WEPWB113 [1.410 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB113

About •

Received ※ 20 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 26 July 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THIXA01

Investigation of Plasma Processing for Coaxial Resonators

960

W. Hartung, W. Chang, K. Elliott, S.H. Kim, T. Konomi, K. Saito, P.R. Tutt, T. Xu
FRIB, East Lansing, Michigan, USA

Plasma processing has been investigated by several facilities as a method to mitigate degradation of SRF cavity performance. It provides an alternative to removal and disassembly of cryomodules for refurbishment of each cavity via repeat etching and rinsing. Promising results have been obtained by several groups. Studies of plasma processing for quarter-wave resonators (QWRs) and half-wave resonators (HWRs) were undertaken at FRIB, where a total of 324 such resonators are presently in operation. Plasma ignition and optimization measurements were done with room-temperature-matched input couplers. Plasma cleaning tests were done on several QWRs using the fundamental power coupler (FPC) to drive the plasma. We investigated the usefulness of higher-order modes (HOMs) to drive the plasma. HOMs allow for less mismatch at the FPC and hence lower field in the coupler relative to the cavity. Before-and-after cold tests showed a significant reduction in field emission X-rays with judicious application of plasma processing.

Slides THIXA01 [2.060 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-THIXA01

About •

Received ※ 01 September 2023 — Accepted ※ 02 September 2023 — Issue date ※ 02 September 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRIBA05

Automation of FRIB SRF Cavities and SC Solenoids Turn-on/off

999

W. Chang, Y. Choi, X.J. Du, W. Hartung, S.H. Kim, T. Konomi, S.R. Kunjir, H. Nguyen, K. Saito, T. Xu, S. Zhao
FRIB, East Lansing, Michigan, USA
A. Facco
INFN/LNL, Legnaro (PD), Italy

The superconducting driver Linac for the Facility for Rare Isotope Beams (FRIB) is a heavy ion accelerator that accelerate ions to 200 MeV per nucleon. The Linac has 46 cryomodules that contain 324 superconducting radio frequency (SRF) cavities and 69 superconducting (SC) solenoid packages. For operation of all cryomodules with high efficiency and reliability, automation for SRF cavity and SC solenoid fast turn-on/off is essentially. Based on cryomodule commissioning results and expert experience, all manual cavity and solenoid turn-on/off procedures and steps have been replaced by automatic programs for FRIB linac operation. This allows the operators to turn the systems on and off without expert-level training. Automation reduces the risk of human error, speeds up beam recovery after user access to experimental areas, and increases beam availability. The cavity turn-on procedure makes sure that the cavity can operate at low field with expected read backs, ramps up the field, and makes sure that the RF amplitude and phase are stable. The design, implementation, and operating experience with automation will be presented.

Slides FRIBA05 [3.503 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-FRIBA05

About •

Received ※ 29 June 2023 — Revised ※ 16 August 2023 — Accepted ※ 21 August 2023 — Issue date ※ 21 August 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRIBA07

Status of the SLAC/MSU SRF Gun Development Project

1003

S.J. Miller, Y. Al-Mahmoud, W. Chang, Y. Choi, C. Compton, X.J. Du, K. Elliott, W. Hartung, J.D. Hulbert, S.H. Kim, T. Konomi, D.G. Morris, M.S. Patil, L. Popielarski, K. Saito, A. Taylor, B.P. Tousignant, J. Wei, J.D. Wenstrom, K. Witgen, T. Xu
FRIB, East Lansing, Michigan, USA
C. Adolphsen, R. Coy, F. Ji, M.J. Murphy, J. Smedley, L. Xiao
SLAC, Menlo Park, California, USA
A. Arnold, S. Gatzmaga, P. Murcek, J. Teichert, R. Xiang
HZDR, Dresden, Germany
M.P. Kelly, T.B. Petersen, P. Piot
ANL, Lemont, Illinois, USA
J.W. Lewellen
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by the Department of Energy under Contract DE-AC02-76SF00515
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.

Slides FRIBA07 [9.655 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-FRIBA07

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Received ※ 15 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 11 July 2023

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TUPTB049

Horizontal Test Results of 1.3 GHz Superconducting RF Gun #2 at KEK

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T. Konomi, K. Hara, Y. Honda, K. Hosoyama, H. Inoue, E. Kako, Y. Kondo, M. Masuzawa, M. Omet, T. Takatomi, A. Terashima, K. Tsuchiya, R. Ueki, K. Umemori, X. Wang
KEK, Ibaraki, Japan

Superconducting radio-frequency (SRF) electron guns are attractive for delivery of beams at a high bunch repetition rate with a high accelerating field. KEK has been developing the SRF gun to demonstrate basic performance. The SRF gun consists of 1.3 GHz and 1.5 cell SRF gun cavity and K2CsSb photocathode coated on 2K cathode plug. In the vertical test, the surface peak electric field and the surface peak magnetic field reached to 75 MV/m and 170 mT respectively. The SRF gun was installed to horizontal multipurpose cryostat equipped with a superconducting solenoid, photocathode preparation chamber and beam diagnostic line. The results showed the peak surface electric field degraded to 42 MV/m. We suspect that cavity was contaminated during assembly. In this presentation, we will present the high gradient performance in vertical and horizontal test and individual test for each beam line components.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB049

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Received ※ 24 June 2023 — Revised ※ 28 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 15 July 2023

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)