SRF2021 - List of Authors (Kim, S.H.)

Paper	Title	Page
SUPCAV018	First N-Doping and Mid-T Baking of Medium-ß 644 MHz 5-Cell Elliptical Superconducting RF Cavities for Michigan State University’s Facility for Rare Isotope Beams	53
	K.E. McGee, S.H. Kim, P.N. Ostroumov, A. Taylor FRIB, East Lansing, Michigan, USA G.V. Eremeev, M. Martinello, A.V. Netepenko Fermilab, Batavia, Illinois, USA M.P. Kelly, T. Reid ANL, Lemont, Illinois, USA
	Funding: Work supported by the 2020 US DoE, Office of Science Graduate Student Research award (SCGSR), and US DoE, Office of Science, High Energy Physics under Cooperative Agreement award number DE-SC0018362 Two hadron linacs currently under development in the US, the PIP-II linac at Fermi National Accelerator Laboratory (FNAL) and the upgrade for Michigan State University’s Facility For Rare Isotope Beams (FRIB), will employ 650 and 644 MHz ß-0.6 elliptical superconducting cavities respectively to meet their design energy requirements. The desired CW operation modes of these two linacs sets Q-factor requirements well above any previously achieved for cavities at this operating frequency and velocity, driving the need to explore new high-Q treatments. The N-doping technique developed at FNAL and employed at an industrial scale to the LCLS-II cryomodules is a strong candidate for high-Q treatments, but work is needed to refine the treatment to the lower operating frequency and velocity regime. We present the first results of the first N-doping tests and a "mid-T" bake test in the FRIB 644 MHz 5-cell elliptical cavities.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-SUPCAV018
About •	Received ※ 23 June 2021 — Revised ※ 16 November 2021 — Accepted ※ 08 May 2022 — Issue date ※ 08 May 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOOFAV10	Completion of FRIB Superconducting Linac and Phased Beam Commissioning	197
	T. Xu, Y. Al-Mahmoud, H. Ao, J. Asciutto, B. Bird, J. Bonofiglio, B. Bullock, N.K. Bultman, F. Casagrande, W. Chang, Y. Choi, C. Compton, J.C. Curtin, K.D. Davidson, K. Elliott, A. Facco, V. Ganni, A. Ganshyn, J. Gao, P.E. Gibson, Y. Hao, W. Hartung, N.M. Hasan, L. Hodges, K. Holland, J.D. Hulbert, M. Ikegami, T. Kanemura, S.H. Kim, P. Knudsen, Z. Li, S.M. Lidia, G. Machicoane, C. Magsig, P.E. Manwiller, F. Marti, T. Maruta, K.E. McGee, E.S. Metzgar, S.J. Miller, D.G. Morris, H. Nguyen, P.N. Ostroumov, A.S. Plastun, J.T. Popielarski, L. Popielarski, X. Rao, M.A. Reaume, H.T. Ren, K. Saito, M. Shuptar, A. Stolz, A. Taylor, B.P. Tousignant, A.D.F. Victory, D.R. Victory, J. Wei, E.M. Wellman, J.D. Wenstrom, Y. Yamazaki, C. Zhang, Q. Zhao, S. Zhao FRIB, East Lansing, Michigan, USA K. Hosoyama KEK, Ibaraki, Japan M.P. Kelly ANL, Lemont, Illinois, USA R.E. Laxdal TRIUMF, Vancouver, Canada M. Wiseman JLab, Newport News, Virginia, USA
	Funding: This work is supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. The Facility for Rare Isotope Beams (FRIB) is an ac-celerator-based facility funded by the US Department of Energy for nuclear physics research. FRIB is nearing the end of technical construction, with first user beams ex-pected in Summer 2022. Key features are the delivery of a variety of rare isotopes with a beam energy of ’ 200 MeV/u and a beam power of up to 400 kW. The facility is upgradable to 400 MeV/u and multi-user capability. The FRIB driver linac consists of 324 superconducting resonators and 69 superconducting solenoids in 46 cry-omodules. FRIB is the first linac to deploy a large number of HWRs (220) and the first heavy ion linac to operate at 2 K. We report on the completion of production and in-stallation of the FRIB cryomodules and phased beam commissioning results.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-MOOFAV10
About •	Received ※ 12 August 2021 — Revised ※ 16 August 2021 — Accepted ※ 21 August 2021 — Issue date ※ 04 May 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPTEV010	RF System Experience for FRIB Half Wave Resonators	226
	S. Zhao, W. Chang, E. Daykin, E. Gutierrez, S.H. Kim, S.R. Kunjir, T.L. Larter, D.G. Morris, J.T. Popielarski FRIB, East Lansing, Michigan, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. The installation and commissioning of the FRIB superconducting linac adopts a phased strategy. In SRF’19 we reported the progress on the commissioning of the linear segment 1 (LS1) which contains mainly the quarter wave resonators (QWRs). In this paper, we will report the recent progress on the commissioning of the remainder of the linac, including linear segment 2 (LS2), folding segment 2 (FS2) and linear segment 3 (LS3), focusing on the RF system experience for the half wave resonators (HWRs). Compared to the QWRs, the HWRs have a different type of tuner, run at higher power levels and have additional components (for example, high voltage bias tee for multipacting suppression and spark detector). Topics such as nonlinear tuner control for the pneumatic tuners; auto turn on/off implementation; and early issues and failures will be discussed in more detail.
	Poster MOPTEV010 [1.604 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-MOPTEV010
About •	Received ※ 22 June 2021 — Revised ※ 22 August 2021 — Accepted ※ 16 November 2021 — Issue date ※ 22 November 2021
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPCAV005	Toward Qualifications of HB and LB 650 MHz Cavities for the Prototype Cryomodules for the PIP-II Project	448
	M. Martinello, D.J. Bice, C. Boffo, S.K. Chandrasekaran, G.V. Eremeev, F. Furuta, T.N. Khabiboulline, K.E. McGee, A.V. Netepenko, J.P. Ozelis, A.I. Sukhanov, G. Wu Fermilab, Batavia, Illinois, USA M. Bagre, V. Jain, A. Puntambekar, S. Raghvendra, P. Shrivastava RRCAT, Indore (M.P.), India M. Bertucci, A. Bosotti, C. Pagani, R. Paparella INFN/LASA, Segrate (MI), Italy P. Bhattacharyya, S. Ghosh, S. Ghosh, A. Mandal, S. Seth, S. Som VECC, Kolkata, India M.P. Kelly, T. Reid ANL, Lemont, Illinois, USA S.H. Kim, K.E. McGee, P.N. Ostroumov FRIB, East Lansing, Michigan, USA K.K. Mistri, P.N. Prakash IUAC, New Delhi, India
	High-beta (HB) and low-beta (LB) 650 MHz cryomodules are key components of the Proton Improvement Plan II (PIP-II) project. In this contribution we present the results of several 5-cell HB650 cavities that have been processed and tested with the purpose of qualifying them for the prototype cryomodule assembly, which will take place later this year. We also present the first results obtained in LB650 single-cell cavities process optimization. Taking advantage of their very similar geometry, we are also analyzing the effect of different surface treatments in FRIB’s 5-cell medium-beta 644MHz cavities. Cavities processed with N-doping and mid-T baking showed very promising results in term of both Q-factors and accelerating gradient for these low-beta structures.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-TUPCAV005
About •	Received ※ 01 July 2021 — Accepted ※ 02 November 2021 — Issue date ※ 16 May 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPTEV011	Development of In-Situ Plasma Cleaning for the FRIB SRF Linac	657
	C. Zhang, W. Chang, K. Elliott, W. Hartung, S.H. Kim, J.T. Popielarski, K. Saito, T. Xu FRIB, East Lansing, Michigan, USA
	Development of techniques for in-situ plasma cleaning of quarter-wave and half-wave resonator cryomodules is underway at the Facility for Rare Isotope Beams (FRIB) at Michigan State University. If SRF cavity performance degradation is seen during future FRIB linac operation, in-situ plasma cleaning may help to restore performance without disassembly of the cavities from the cryomodules for off-line cleaning. A plasma cleaning feasibility study for FRIB cryomodules indicates that plasma cleaning can be done on-line without modifications to the RF couplers or cryomodules. Initial bench measurements have been performed on a FRIB half-wave resonator using noble gases (Ne, Ar), with and without added oxygen gas. The plasma ignition threshold has been measured as a function of gas pressure and composition. Studies of plasma cleaning efficacy are underway. Results will be presented.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-WEPTEV011
About •	Received ※ 04 July 2021 — Revised ※ 08 November 2021 — Accepted ※ 24 December 2021 — Issue date ※ 01 March 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPTEV002	Enhanced Pneumatic Tuner Control for FRIB Half-Wave Resonators	829
	W. Chang, W. Hartung, S.H. Kim, J.T. Popielarski, T. Xu, C. Zhang, S. Zhao FRIB, East Lansing, Michigan, USA
	The superconducting driver linac for the Facility for Rare Isotope Beams (FRIB) includes a total of 46 cryomodules; 31 cryomodules contain half-wave resonators (HWRs) with pneumatic tuners. Pneumatic tuner control is via solenoid valves connecting the tuner to a helium gas supply manifold and a gas return line. For precise compensation of cavity detuning over a small range, the control voltage for the solenoid valves must be calibrated. Some valves have hysteresis in the gas flow rate as a function of control voltage, such that their response may be nonlinear and not repeatable–this makes the control algorithm challenging. To improve the system performance, a new pneumatic tuner control system was developed which regulates the position of one stepper motor instead of the two solenoid valves.
	Poster THPTEV002 [1.325 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-THPTEV002
About •	Received ※ 24 June 2021 — Revised ※ 15 December 2021 — Accepted ※ 17 February 2022 — Issue date ※ 16 May 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

First N-Doping and Mid-T Baking of Medium-ß 644 MHz 5-Cell Elliptical Superconducting RF Cavities for Michigan State University’s Facility for Rare Isotope Beams

53

K.E. McGee, S.H. Kim, P.N. Ostroumov, A. Taylor
FRIB, East Lansing, Michigan, USA
G.V. Eremeev, M. Martinello, A.V. Netepenko
Fermilab, Batavia, Illinois, USA
M.P. Kelly, T. Reid
ANL, Lemont, Illinois, USA

Funding: Work supported by the 2020 US DoE, Office of Science Graduate Student Research award (SCGSR), and US DoE, Office of Science, High Energy Physics under Cooperative Agreement award number DE-SC0018362
Two hadron linacs currently under development in the US, the PIP-II linac at Fermi National Accelerator Laboratory (FNAL) and the upgrade for Michigan State University’s Facility For Rare Isotope Beams (FRIB), will employ 650 and 644 MHz ß-0.6 elliptical superconducting cavities respectively to meet their design energy requirements. The desired CW operation modes of these two linacs sets Q-factor requirements well above any previously achieved for cavities at this operating frequency and velocity, driving the need to explore new high-Q treatments. The N-doping technique developed at FNAL and employed at an industrial scale to the LCLS-II cryomodules is a strong candidate for high-Q treatments, but work is needed to refine the treatment to the lower operating frequency and velocity regime. We present the first results of the first N-doping tests and a "mid-T" bake test in the FRIB 644 MHz 5-cell elliptical cavities.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-SUPCAV018

About •

Received ※ 23 June 2021 — Revised ※ 16 November 2021 — Accepted ※ 08 May 2022 — Issue date ※ 08 May 2022

Cite •

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

MOOFAV10

Completion of FRIB Superconducting Linac and Phased Beam Commissioning

197

T. Xu, Y. Al-Mahmoud, H. Ao, J. Asciutto, B. Bird, J. Bonofiglio, B. Bullock, N.K. Bultman, F. Casagrande, W. Chang, Y. Choi, C. Compton, J.C. Curtin, K.D. Davidson, K. Elliott, A. Facco, V. Ganni, A. Ganshyn, J. Gao, P.E. Gibson, Y. Hao, W. Hartung, N.M. Hasan, L. Hodges, K. Holland, J.D. Hulbert, M. Ikegami, T. Kanemura, S.H. Kim, P. Knudsen, Z. Li, S.M. Lidia, G. Machicoane, C. Magsig, P.E. Manwiller, F. Marti, T. Maruta, K.E. McGee, E.S. Metzgar, S.J. Miller, D.G. Morris, H. Nguyen, P.N. Ostroumov, A.S. Plastun, J.T. Popielarski, L. Popielarski, X. Rao, M.A. Reaume, H.T. Ren, K. Saito, M. Shuptar, A. Stolz, A. Taylor, B.P. Tousignant, A.D.F. Victory, D.R. Victory, J. Wei, E.M. Wellman, J.D. Wenstrom, Y. Yamazaki, C. Zhang, Q. Zhao, S. Zhao
FRIB, East Lansing, Michigan, USA
K. Hosoyama
KEK, Ibaraki, Japan
M.P. Kelly
ANL, Lemont, Illinois, USA
R.E. Laxdal
TRIUMF, Vancouver, Canada
M. Wiseman
JLab, Newport News, Virginia, USA

Funding: This work is supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
The Facility for Rare Isotope Beams (FRIB) is an ac-celerator-based facility funded by the US Department of Energy for nuclear physics research. FRIB is nearing the end of technical construction, with first user beams ex-pected in Summer 2022. Key features are the delivery of a variety of rare isotopes with a beam energy of ’ 200 MeV/u and a beam power of up to 400 kW. The facility is upgradable to 400 MeV/u and multi-user capability. The FRIB driver linac consists of 324 superconducting resonators and 69 superconducting solenoids in 46 cry-omodules. FRIB is the first linac to deploy a large number of HWRs (220) and the first heavy ion linac to operate at 2 K. We report on the completion of production and in-stallation of the FRIB cryomodules and phased beam commissioning results.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-MOOFAV10

About •

Received ※ 12 August 2021 — Revised ※ 16 August 2021 — Accepted ※ 21 August 2021 — Issue date ※ 04 May 2022

Cite •

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

MOPTEV010

RF System Experience for FRIB Half Wave Resonators

226

S. Zhao, W. Chang, E. Daykin, E. Gutierrez, S.H. Kim, S.R. Kunjir, T.L. Larter, D.G. Morris, J.T. Popielarski
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
The installation and commissioning of the FRIB superconducting linac adopts a phased strategy. In SRF’19 we reported the progress on the commissioning of the linear segment 1 (LS1) which contains mainly the quarter wave resonators (QWRs). In this paper, we will report the recent progress on the commissioning of the remainder of the linac, including linear segment 2 (LS2), folding segment 2 (FS2) and linear segment 3 (LS3), focusing on the RF system experience for the half wave resonators (HWRs). Compared to the QWRs, the HWRs have a different type of tuner, run at higher power levels and have additional components (for example, high voltage bias tee for multipacting suppression and spark detector). Topics such as nonlinear tuner control for the pneumatic tuners; auto turn on/off implementation; and early issues and failures will be discussed in more detail.

Poster MOPTEV010 [1.604 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-MOPTEV010

About •

Received ※ 22 June 2021 — Revised ※ 22 August 2021 — Accepted ※ 16 November 2021 — Issue date ※ 22 November 2021

Cite •

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

TUPCAV005

Toward Qualifications of HB and LB 650 MHz Cavities for the Prototype Cryomodules for the PIP-II Project

448

M. Martinello, D.J. Bice, C. Boffo, S.K. Chandrasekaran, G.V. Eremeev, F. Furuta, T.N. Khabiboulline, K.E. McGee, A.V. Netepenko, J.P. Ozelis, A.I. Sukhanov, G. Wu
Fermilab, Batavia, Illinois, USA
M. Bagre, V. Jain, A. Puntambekar, S. Raghvendra, P. Shrivastava
RRCAT, Indore (M.P.), India
M. Bertucci, A. Bosotti, C. Pagani, R. Paparella
INFN/LASA, Segrate (MI), Italy
P. Bhattacharyya, S. Ghosh, S. Ghosh, A. Mandal, S. Seth, S. Som
VECC, Kolkata, India
M.P. Kelly, T. Reid
ANL, Lemont, Illinois, USA
S.H. Kim, K.E. McGee, P.N. Ostroumov
FRIB, East Lansing, Michigan, USA
K.K. Mistri, P.N. Prakash
IUAC, New Delhi, India

High-beta (HB) and low-beta (LB) 650 MHz cryomodules are key components of the Proton Improvement Plan II (PIP-II) project. In this contribution we present the results of several 5-cell HB650 cavities that have been processed and tested with the purpose of qualifying them for the prototype cryomodule assembly, which will take place later this year. We also present the first results obtained in LB650 single-cell cavities process optimization. Taking advantage of their very similar geometry, we are also analyzing the effect of different surface treatments in FRIB’s 5-cell medium-beta 644MHz cavities. Cavities processed with N-doping and mid-T baking showed very promising results in term of both Q-factors and accelerating gradient for these low-beta structures.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-TUPCAV005

About •

Received ※ 01 July 2021 — Accepted ※ 02 November 2021 — Issue date ※ 16 May 2022

Cite •

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

WEPTEV011

Development of In-Situ Plasma Cleaning for the FRIB SRF Linac

657

C. Zhang, W. Chang, K. Elliott, W. Hartung, S.H. Kim, J.T. Popielarski, K. Saito, T. Xu
FRIB, East Lansing, Michigan, USA

Development of techniques for in-situ plasma cleaning of quarter-wave and half-wave resonator cryomodules is underway at the Facility for Rare Isotope Beams (FRIB) at Michigan State University. If SRF cavity performance degradation is seen during future FRIB linac operation, in-situ plasma cleaning may help to restore performance without disassembly of the cavities from the cryomodules for off-line cleaning. A plasma cleaning feasibility study for FRIB cryomodules indicates that plasma cleaning can be done on-line without modifications to the RF couplers or cryomodules. Initial bench measurements have been performed on a FRIB half-wave resonator using noble gases (Ne, Ar), with and without added oxygen gas. The plasma ignition threshold has been measured as a function of gas pressure and composition. Studies of plasma cleaning efficacy are underway. Results will be presented.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-WEPTEV011

About •

Received ※ 04 July 2021 — Revised ※ 08 November 2021 — Accepted ※ 24 December 2021 — Issue date ※ 01 March 2022

Cite •

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

THPTEV002

Enhanced Pneumatic Tuner Control for FRIB Half-Wave Resonators

829

W. Chang, W. Hartung, S.H. Kim, J.T. Popielarski, T. Xu, C. Zhang, S. Zhao
FRIB, East Lansing, Michigan, USA

The superconducting driver linac for the Facility for Rare Isotope Beams (FRIB) includes a total of 46 cryomodules; 31 cryomodules contain half-wave resonators (HWRs) with pneumatic tuners. Pneumatic tuner control is via solenoid valves connecting the tuner to a helium gas supply manifold and a gas return line. For precise compensation of cavity detuning over a small range, the control voltage for the solenoid valves must be calibrated. Some valves have hysteresis in the gas flow rate as a function of control voltage, such that their response may be nonlinear and not repeatable–this makes the control algorithm challenging. To improve the system performance, a new pneumatic tuner control system was developed which regulates the position of one stepper motor instead of the two solenoid valves.

Poster THPTEV002 [1.325 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-THPTEV002

About •

Received ※ 24 June 2021 — Revised ※ 15 December 2021 — Accepted ※ 17 February 2022 — Issue date ※ 16 May 2022

Cite •

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