SRF2023 - List of Authors (Wu, G.)

Paper	Title	Page
MOPMB024	Flux Expulsion Studies of Niobium Material of 650 MHz Cavities for PIP-II	141
TUPTB003	use link to see paper's listing under its alternate paper code
	K.E. McGee FRIB, East Lansing, Michigan, USA F. Furuta, M. Martinello, O.S. Melnychuk, A.V. Netepenko, G. Wu, Y. Xie Fermilab, Batavia, Illinois, USA
	Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. Two different vendors supplied the niobium sheet material for PIP-II 5-cell 650 MHz cavities, which was characterized by multiple different ASTM sizes. Cavities subsequently fabricated from these sheets were heat-treated at various temperatures, then the cavities’ flux-expulsion performance was measured. Where the initial measurements of vendor O materials showed that nearly all flux remained trapped despite a high thermal gradient, 900C heat treatment subsequently improved the flux expulsion to an acceptable rate. Understanding and characterizing vendor O materials in this way is key for upcoming and future projects planning to employ niobium sheet from this supplier.
	Poster MOPMB024 [4.064 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB024
About •	Received ※ 26 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 19 August 2023 — Issue date ※ 21 August 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMB030	Medium Temperature Furnace Baking of Low-beta 650 MHz Five-cell Cavities	158
	G. Wu, S.K. Chandrasekaran, V. Chouhan, G.V. Eremeev, F. Furuta, K.E. McGee, A.A. Murthy, A.V. Netepenko, J.P. Ozelis, H. Park, S. Posen Fermilab, Batavia, Illinois, USA
	Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. Medium Temperature baking of low beta 650 MHz cavities was conducted in a UHV furnace. A systematic study of cavity surface resistance components, residual and BCS, was conducted, including analyzing surface resistance due to trapped magnetic flux. Cavities showed an average 4.5 nano-ohm surface resistance at 17 MV/m under 2 K, which meets PIP-II specifications with a 40% margin. The results provided helpful information for the PIP-II project to optimize the cavity processing recipe for cryomodule application. The results were compared to the 1.3 GHz cavity that received a similar furnace baking.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB030
About •	Received ※ 19 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 18 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB041	Visual, Optical and Replica Inspections: Surface Preparation of 650 MHz Nb Cavity for PIP-II Linac	507
	V. Chouhan, D.J. Bice, D.A. Burk, M.K. Ng, G. Wu Fermilab, Batavia, Illinois, USA
	Surface preparation of niobium superconducting RF cavities is a critical step for achieving good RF performance under the superconducting state. Surface defect, roughness, and contamination affect the accelerating gradient and quality factor of the cavities. We report surface inspection methods used to control the surface processing of 650 MHz cavities that will be used in the pre-production cryomodule for PIP-II linac. The cavity surface was routinely inspected visually, with an optical camera, and by microscopic scanning of surface replicas. This article covers details on the surface inspection methods and surface polishing process used to repair the surface.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB041
About •	Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 12 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB042	Latest Development of Electropolishing Optimization for 650 MHz Cavity	512
	V. Chouhan, D.J. Bice, D.A. Burk, S.K. Chandrasekaran, A.T. Cravatta, P.F. Dubiel, G.V. Eremeev, F. Furuta, O.S. Melnychuk, A.V. Netepenko, M.K. Ng, J.P. Ozelis, H. Park, T.J. Ring, G. Wu Fermilab, Batavia, Illinois, USA B.M. Guilfoyle, M.P. Kelly, T. Reid ANL, Lemont, Illinois, USA
	Electropolishing (EP) of 1.3 GHz niobium (Nb) superconducting RF cavities is conducted to achieve a desired smooth and contaminant-free surface that yields good RF performance. Achieving a smooth surface of a large-sized elliptical cavity with the standard EP conditions was found to be challenging. This work aimed to conduct a systematic parametric EP study to understand the effects of various EP parameters on the surface of 650 MHz cavities used in PIP-II linac. Parameters optimized in this study provided a smooth surface of the cavities. The electropolished cavities met the baseline requirement of field gradient and qualified for further surface treatment to improve the cavity quality factor.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB042
About •	Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 06 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB047	The Evaluation of Mechanical Properties of LB650 Cavities	536
	G. Wu, S.D. Adams, D.J. Bice, S.K. Chandrasekaran, I.V. Gonin, C.J. Grimm, J.P. Holzbauer, T.N. Khabiboulline, C.S. Narug, J.P. Ozelis, H. Park, G.V. Romanov, R. Thiede, R. Treece, A.D. Wixson Fermilab, Batavia, Illinois, USA K.E. McGee FRIB, East Lansing, Michigan, USA
	Funding: This manuscript has been authored by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. The 650 MHz cavities have a stronger requirement of niobium mechanical properties because of the geometric shape of the cavity due to reduced beta. The mechanical property of the niobium half-cell was measured following various heat treatments. The 5-cell cavities were tested in a controlled drop test fashion and the real-world road test. The result showed that the 900C heat treatment was compatible with cavity handling and transportation during production. The test provides the bases of the transportation specification and shipping container design guidelines.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB047
About •	Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 14 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEIXA05	Electropolishing Study on Nitrogen-Doped Niobium Surface	641
	V. Chouhan, T.J. Ring, G. Wu Fermilab, Batavia, Illinois, USA E.A.S. Viklund NU, Evanston, Illinois, USA
	The nitrogen doping (N-doping) process is applied to niobium (Nb) superconducting cavities to enhance their quality factors. The N-doping is followed by an electropolishing process that provides the final surface of the cavities. A controlled EP process is necessary to get the benefit of N-doping and achieve a high accelerating gradient. We have performed electropolishing of N-doped Nb surface under various conditions to understand their impact on the surface. A modified EP process was developed to obtain a smooth pit-free surface.
	Slides WEIXA05 [17.622 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEIXA05
About •	Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 03 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWB075	Impact of Solenoid Induced Residual Magnetic Fields on the Prototype SSR1 CM Performance	760
	D. Passarelli, J. Bernardini, C. Boffo, S.K. Chandrasekaran, A.H. Hogberg, T.N. Khabiboulline, J.P. Ozelis, M. Parise, V. Roger, G.V. Romanov, A.I. Sukhanov, G. Wu, Y. Xie, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Funding: This manuscript has been authored by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. A prototype cryomodule containing eight Single Spoke Resonators type-1 (SSR1) operating at 325 MHz and four superconducting focusing lenses was successfully assembled, cold tested, and accelerated beam in the framework of the PIP-II project at Fermilab. The impact of induced residual magnetic fields from the solenoids on performance of cavities is presented in this contribution. In addition, design optimizations for the production cryomodules as a result of this impact are highlighted.
	Poster WEPWB075 [2.429 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB075
About •	Received ※ 26 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 11 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWB076	Low Particulates Nitrogen Purge and Backfill during Prototype HB650 Cryomodule String Assembly	765
	T.J. Ring, M.B. Quinlan, G. Wu Fermilab, Batavia, Illinois, USA
	Funding: This manuscript has been authored by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. A low particulate vacuum and purging system was developed to support PIP-II cryomodule string assembly. The overpressure can be controlled at a precision of 1 mbar above the atmospheric pressure regardless of the cavity or string assembly air volume. The system minimized the risk of uncontrolled nitrogen flow during the string assembly. Design features will be presented.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB076
About •	Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 09 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

MOPMB024

Flux Expulsion Studies of Niobium Material of 650 MHz Cavities for PIP-II

141

TUPTB003

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

K.E. McGee
FRIB, East Lansing, Michigan, USA
F. Furuta, M. Martinello, O.S. Melnychuk, A.V. Netepenko, G. Wu, Y. Xie
Fermilab, Batavia, Illinois, USA

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
Two different vendors supplied the niobium sheet material for PIP-II 5-cell 650 MHz cavities, which was characterized by multiple different ASTM sizes. Cavities subsequently fabricated from these sheets were heat-treated at various temperatures, then the cavities’ flux-expulsion performance was measured. Where the initial measurements of vendor O materials showed that nearly all flux remained trapped despite a high thermal gradient, 900C heat treatment subsequently improved the flux expulsion to an acceptable rate. Understanding and characterizing vendor O materials in this way is key for upcoming and future projects planning to employ niobium sheet from this supplier.

Poster MOPMB024 [4.064 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB024

About •

Received ※ 26 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 19 August 2023 — Issue date ※ 21 August 2023

Cite •

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

MOPMB030

Medium Temperature Furnace Baking of Low-beta 650 MHz Five-cell Cavities

158

G. Wu, S.K. Chandrasekaran, V. Chouhan, G.V. Eremeev, F. Furuta, K.E. McGee, A.A. Murthy, A.V. Netepenko, J.P. Ozelis, H. Park, S. Posen
Fermilab, Batavia, Illinois, USA

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
Medium Temperature baking of low beta 650 MHz cavities was conducted in a UHV furnace. A systematic study of cavity surface resistance components, residual and BCS, was conducted, including analyzing surface resistance due to trapped magnetic flux. Cavities showed an average 4.5 nano-ohm surface resistance at 17 MV/m under 2 K, which meets PIP-II specifications with a 40% margin. The results provided helpful information for the PIP-II project to optimize the cavity processing recipe for cryomodule application. The results were compared to the 1.3 GHz cavity that received a similar furnace baking.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB030

About •

Received ※ 19 June 2023 — Revised ※ 23 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 18 July 2023

Cite •

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

TUPTB041

Visual, Optical and Replica Inspections: Surface Preparation of 650 MHz Nb Cavity for PIP-II Linac

507

V. Chouhan, D.J. Bice, D.A. Burk, M.K. Ng, G. Wu
Fermilab, Batavia, Illinois, USA

Surface preparation of niobium superconducting RF cavities is a critical step for achieving good RF performance under the superconducting state. Surface defect, roughness, and contamination affect the accelerating gradient and quality factor of the cavities. We report surface inspection methods used to control the surface processing of 650 MHz cavities that will be used in the pre-production cryomodule for PIP-II linac. The cavity surface was routinely inspected visually, with an optical camera, and by microscopic scanning of surface replicas. This article covers details on the surface inspection methods and surface polishing process used to repair the surface.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB041

About •

Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 12 July 2023

Cite •

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

TUPTB042

Latest Development of Electropolishing Optimization for 650 MHz Cavity

512

V. Chouhan, D.J. Bice, D.A. Burk, S.K. Chandrasekaran, A.T. Cravatta, P.F. Dubiel, G.V. Eremeev, F. Furuta, O.S. Melnychuk, A.V. Netepenko, M.K. Ng, J.P. Ozelis, H. Park, T.J. Ring, G. Wu
Fermilab, Batavia, Illinois, USA
B.M. Guilfoyle, M.P. Kelly, T. Reid
ANL, Lemont, Illinois, USA

Electropolishing (EP) of 1.3 GHz niobium (Nb) superconducting RF cavities is conducted to achieve a desired smooth and contaminant-free surface that yields good RF performance. Achieving a smooth surface of a large-sized elliptical cavity with the standard EP conditions was found to be challenging. This work aimed to conduct a systematic parametric EP study to understand the effects of various EP parameters on the surface of 650 MHz cavities used in PIP-II linac. Parameters optimized in this study provided a smooth surface of the cavities. The electropolished cavities met the baseline requirement of field gradient and qualified for further surface treatment to improve the cavity quality factor.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB042

About •

Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 06 July 2023

Cite •

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

TUPTB047

The Evaluation of Mechanical Properties of LB650 Cavities

536

G. Wu, S.D. Adams, D.J. Bice, S.K. Chandrasekaran, I.V. Gonin, C.J. Grimm, J.P. Holzbauer, T.N. Khabiboulline, C.S. Narug, J.P. Ozelis, H. Park, G.V. Romanov, R. Thiede, R. Treece, A.D. Wixson
Fermilab, Batavia, Illinois, USA
K.E. McGee
FRIB, East Lansing, Michigan, USA

Funding: This manuscript has been authored by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
The 650 MHz cavities have a stronger requirement of niobium mechanical properties because of the geometric shape of the cavity due to reduced beta. The mechanical property of the niobium half-cell was measured following various heat treatments. The 5-cell cavities were tested in a controlled drop test fashion and the real-world road test. The result showed that the 900C heat treatment was compatible with cavity handling and transportation during production. The test provides the bases of the transportation specification and shipping container design guidelines.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB047

About •

Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 14 July 2023

Cite •

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

WEIXA05

Electropolishing Study on Nitrogen-Doped Niobium Surface

641

V. Chouhan, T.J. Ring, G. Wu
Fermilab, Batavia, Illinois, USA
E.A.S. Viklund
NU, Evanston, Illinois, USA

The nitrogen doping (N-doping) process is applied to niobium (Nb) superconducting cavities to enhance their quality factors. The N-doping is followed by an electropolishing process that provides the final surface of the cavities. A controlled EP process is necessary to get the benefit of N-doping and achieve a high accelerating gradient. We have performed electropolishing of N-doped Nb surface under various conditions to understand their impact on the surface. A modified EP process was developed to obtain a smooth pit-free surface.

Slides WEIXA05 [17.622 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEIXA05

About •

Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 03 July 2023

Cite •

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

WEPWB075

Impact of Solenoid Induced Residual Magnetic Fields on the Prototype SSR1 CM Performance

760

D. Passarelli, J. Bernardini, C. Boffo, S.K. Chandrasekaran, A.H. Hogberg, T.N. Khabiboulline, J.P. Ozelis, M. Parise, V. Roger, G.V. Romanov, A.I. Sukhanov, G. Wu, Y. Xie, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Funding: This manuscript has been authored by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
A prototype cryomodule containing eight Single Spoke Resonators type-1 (SSR1) operating at 325 MHz and four superconducting focusing lenses was successfully assembled, cold tested, and accelerated beam in the framework of the PIP-II project at Fermilab. The impact of induced residual magnetic fields from the solenoids on performance of cavities is presented in this contribution. In addition, design optimizations for the production cryomodules as a result of this impact are highlighted.

Poster WEPWB075 [2.429 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB075

About •

Received ※ 26 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 11 July 2023

Cite •

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

WEPWB076

Low Particulates Nitrogen Purge and Backfill during Prototype HB650 Cryomodule String Assembly

765

T.J. Ring, M.B. Quinlan, G. Wu
Fermilab, Batavia, Illinois, USA

Funding: This manuscript has been authored by Fermi Research Alliance, LLC, under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
A low particulate vacuum and purging system was developed to support PIP-II cryomodule string assembly. The overpressure can be controlled at a precision of 1 mbar above the atmospheric pressure regardless of the cavity or string assembly air volume. The system minimized the risk of uncontrolled nitrogen flow during the string assembly. Design features will be presented.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB076

About •

Received ※ 19 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 09 July 2023

Cite •

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