SRF2019 - List of Authors (Gonnella, D.)

Paper	Title	Page
MOP045	The LCLS-II HE High Q and Gradient R&D Program	154
	D. Gonnella, S. Aderhold, A. Burrill, G.R. Hays, T.O. Raubenheimer, M.C. Ross SLAC, Menlo Park, California, USA D. Bafia, M. Checchin, A. Grassellino, M. Martinello, A.S. Romanenko Fermilab, Batavia, Illinois, USA M. Ge, M. Liepe, S. Posen Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA A.D. Palczewski, C.E. Reece JLab, Newport News, Virginia, USA
	Funding: US DOE and the LCLS-II HE Project The LCLS-II HE project is a high energy upgrade to the superconducting LCLS-II linac. It consists of adding twenty additional 1.3 GHz cryomodules to the linac, with cavities operating at a gradient of 20.8 MV/m with a Q₀ of 2.7·10¹⁰. Performance of LCLS-II cryomodules has suggested that operations at this high of a gradient will not be achievable with the existing cavity recipe employed. Therefore a research program was developed between SLAC, Fermilab, Thomas Jefferson National Accelerator Facility, and Cornell University in order to improve the cavity processing method of the SRF cavities and reach the HE goals. This program explores the doping regime beyond what was done for LCLS-II and also has looked to further developed nitrogen-infusion. Here we will summarize the results from this R\&D program, showing significant improvement on both single-cell and 9-cell cavities compared with the original LCLS-II cavity recipe.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP045
About •	paper received ※ 25 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP057	Study of Flux Trapping Variability between Batches of Tokyo Denkai Niobium used for the LCLS-II Project and Subsequent 9-cell RF Loss Distribution between the Batches	570
	A.D. Palczewski JLab, Newport News, Virginia, USA D. Gonnella SLAC, Menlo Park, California, USA O.S. Melnychuk, D.A. Sergatskov Fermilab, Batavia, Illinois, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. During the LCLS-II project a second batch of niobium was procured from Tokyo Denkai Co Ltd in order to make additional cavities. The original production material came from Two vendors Tokyo Denkai Co., Ltd. (TD) and Ningxia Orient Tantalum Industry Co., Ltd. (OTIC/NX)). It was found TD niobium required a lower annealing temperature (900°C) to obtain satisfactory flux expulsion characteristics compared to NX which required a slightly higher annealing temperature (950°-975°C). In order to ensure the new TD material performed equivalent to the niobium produced 4 year before after 900°C annealing; each heat lot of niobium had its flux expulsion characteristics parametrized and custom thermal treatments developed for each lot. Subsequent pure heat lot 9 cell cavities were made and tested. We will look at the flux expulsion characteristics of each lot, and RF loss of the 9-cell cavities produced using the individual heat lots.
	Poster TUP057 [1.446 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP057
About •	paper received ※ 25 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUP062	New Insights in the Quench Mechanisms in Nitrogen Doped Cavities	592
	D. Bafia, J. Zasadzinski IIT, Chicago, Illinois, USA D. Bafia, D.J. Bice, A. Grassellino, O.S. Melnychuk, A.S. Romanenko, D.A. Sergatskov Fermilab, Batavia, Illinois, USA D. Gonnella SLAC, Menlo Park, California, USA A.D. Palczewski JLab, Newport News, Virginia, USA
	This paper will cover a systematic study of the quench in nitrogen doped cavities: three cavities were sequentially treated/reset with different doping recipes which are known to produce different levels of quench field. Analysis of mean free path and TMAP coupled with sample analysis reveals new insights on the physics of the premature quench in nitrogen doped cavities; new recipes demonstrate the possibility to increase quench fields well beyond 30 MV/m.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP062
About •	paper received ※ 23 June 2019 paper accepted ※ 02 July 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THP049	Commissioning the JLab LERF Cryomodule Test Facility	973
	C. Hovater, R. Bachimanchi, E. Daly, M.A. Drury, L.E. Farrish, J. Gubeli, N.A. Huque, K. Jordan, M.E. Joyce, L.K. King, M. Marchlik, W. Moore, T.E. Plawski, A.D. Solopova, C.M. Wilson JLab, Newport News, Virginia, USA A.L. Benwell, C. Bianchini, D. Gonnella, S.L. Hoobler, K.J. Mattison, J. Nelson, A. Ratti, B.H. Ripman, S. Saraf, L.M. Zacarias SLAC, Menlo Park, California, USA L.R. Doolittle, S. Paiagua, C. Serrano LBNL, Berkeley, California, USA
	The JLab Low Energy Recirculating Facility, LERF, has been modified to support concurrent testing of two LCLS-II cryomodules. The cryomodules are installed in a similar fashion as they would be in the L1 section of the LCLS-II linac, including the floor slope and using all of the LCLS-II hardware and controls for cryomodule cryogenics, vacuum, and RF (SSA and LLRF). From the start, it was intended to use LCLS-II electronics and EPICS software controls for cryomodule testing. In affect the LERF test facility becomes the first opportunity to commission and operate the LCLS-II LINAC hardware and software controls. Support for specific cryomodule high level test applications like Q₀ and HOMs measurements, are being developed from the basic cryomodule control suite. To support the testing, 2 K He is supplied from the CEBAF south linac cryogenic system, where care must be taken when using the LERF test facility to not upset the CEBAF cryogenics plant. This paper discusses the commissioning of the hardware and software development for testing the first two LCLS-II cryomodules.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP049
About •	paper received ※ 22 June 2019 paper accepted ※ 02 July 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THP059	RF Incoming Inspection of 1.3 GHz Cryomodules for LCLS-II at SLAC National Accelerator Laboratory	1014
	S. Aderhold, C. Adolphsen, A. Burrill, D. Gonnella, J. Nelson SLAC, Menlo Park, California, USA
	Funding: This work was supported by the US DOE and the LCLS-II Project. The main part of the SRF linac for the Linac Coherent Light Source II (LCLS-II) at SLAC National Accelerator Laboratory will consist of 35 cryomodules with superconducting RF cavities operating at 1.3 GHz. The cryomodules are assembled and tested at Fermi National Accelerator Laboratory and Thomas Jefferson National Accelerator Facility. Following the transport to SLAC, the cryomodules undergo several incoming inspection steps before ultimately being moved to the tunnel for installation in the linac. The RF part of the incoming inspection covers measurements of a number of parameters like cavity frequency spectrum, notch filter frequency of the higher order mode couplers and external quality factor Q_ext of the input coupler. The inspection results are compared to measurements at the partner labs prior to shipping and the nominal values in order to verify that the cryomodules have not been damaged during the transport and are ready for installation. We present an overview and analysis of the inspections for the cryomodules received to date.
	Poster THP059 [1.223 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP059
About •	paper received ※ 02 July 2019 paper accepted ※ 02 July 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRCAA3	Industrial Cavity Production: Lessons Learned to Push the Boundaries of Nitrogen-Doping	1199
	D. Gonnella, S. Aderhold, A. Burrill, M.C. Ross SLAC, Menlo Park, California, USA E. Daly, G.K. Davis, F. Marhauser, A.D. Palczewski, K.M. Wilson JLab, Newport News, Virginia, USA A. Grassellino, C.J. Grimm, T.N. Khabiboulline, O.S. Melnychuk, S. Posen, D.A. Sergatskov Fermilab, Batavia, Illinois, USA
	Funding: Work supported by US DOE Contract DE-AC02-76SF00515. Nitrogen doping has been proven now in several labs to enhance Q₀ values of 1.3 GHz cavities in the gradient domain favored by CW operation. The choice of doping for the LCLS-II project has given the community a wealth of statistics and experience on the challenge of transferring the doping technology to industry. Overall, industry-produced nitrogen-doped cavities have shown excellent performance, however some technical issues have arisen. This talk focuses on lessons learned from the production of over 300 nitrogen-doped cavities for LCLS-II and how issues were mitigated to further improve performance. Finally, I will discuss pushing the boundaries of nitrogen-doping further by exploring different doping regimes in order to maintain excellent Q₀ performance, while reaching higher quench fields.
	Slides FRCAA3 [16.880 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-FRCAA3
About •	paper received ※ 02 July 2019 paper accepted ※ 03 July 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRCAB7	Plasma Processing to Reduce Field Emission in LCLS-II 1.3 GHz SRF Cavities	1231
SUSP022	use link to see paper's listing under its alternate paper code
TUP067	use link to see paper's listing under its alternate paper code
	B. Giaccone, J. Zasadzinski IIT, Chicago, Illinois, USA P. Berrutti, B. Giaccone, A. Grassellino, M. Martinello Fermilab, Batavia, Illinois, USA M. Doleans ORNL, Oak Ridge, Tennessee, USA D. Gonnella, G. Lanza, M.C. Ross SLAC, Menlo Park, California, USA
	Plasma cleaning for LCLS-II 9-cell 1.3 GHz cavities is under study at Fermilab. Starting from ORNL method, we have developed a new technique for plasma ignition using HOMs. Plasma processing is being applied to contaminated and field emitting cavities, here are discussed the first results in terms of Q and radiation vs E measured before and after treatment. Further studies are ongoing to optimize plasma parameters and to acquire statistics on plasma cleaning effectiveness.
	Slides FRCAB7 [14.701 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-FRCAB7
About •	paper received ※ 23 June 2019 paper accepted ※ 04 July 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

The LCLS-II HE High Q and Gradient R&D Program

154

D. Gonnella, S. Aderhold, A. Burrill, G.R. Hays, T.O. Raubenheimer, M.C. Ross
SLAC, Menlo Park, California, USA
D. Bafia, M. Checchin, A. Grassellino, M. Martinello, A.S. Romanenko
Fermilab, Batavia, Illinois, USA
M. Ge, M. Liepe, S. Posen
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
A.D. Palczewski, C.E. Reece
JLab, Newport News, Virginia, USA

Funding: US DOE and the LCLS-II HE Project
The LCLS-II HE project is a high energy upgrade to the superconducting LCLS-II linac. It consists of adding twenty additional 1.3 GHz cryomodules to the linac, with cavities operating at a gradient of 20.8 MV/m with a Q₀ of 2.7·10¹⁰. Performance of LCLS-II cryomodules has suggested that operations at this high of a gradient will not be achievable with the existing cavity recipe employed. Therefore a research program was developed between SLAC, Fermilab, Thomas Jefferson National Accelerator Facility, and Cornell University in order to improve the cavity processing method of the SRF cavities and reach the HE goals. This program explores the doping regime beyond what was done for LCLS-II and also has looked to further developed nitrogen-infusion. Here we will summarize the results from this R\&D program, showing significant improvement on both single-cell and 9-cell cavities compared with the original LCLS-II cavity recipe.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP045

About •

paper received ※ 25 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

Export •

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

TUP057

Study of Flux Trapping Variability between Batches of Tokyo Denkai Niobium used for the LCLS-II Project and Subsequent 9-cell RF Loss Distribution between the Batches

570

A.D. Palczewski
JLab, Newport News, Virginia, USA
D. Gonnella
SLAC, Menlo Park, California, USA
O.S. Melnychuk, D.A. Sergatskov
Fermilab, Batavia, Illinois, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
During the LCLS-II project a second batch of niobium was procured from Tokyo Denkai Co Ltd in order to make additional cavities. The original production material came from Two vendors Tokyo Denkai Co., Ltd. (TD) and Ningxia Orient Tantalum Industry Co., Ltd. (OTIC/NX)). It was found TD niobium required a lower annealing temperature (900°C) to obtain satisfactory flux expulsion characteristics compared to NX which required a slightly higher annealing temperature (950°-975°C). In order to ensure the new TD material performed equivalent to the niobium produced 4 year before after 900°C annealing; each heat lot of niobium had its flux expulsion characteristics parametrized and custom thermal treatments developed for each lot. Subsequent pure heat lot 9 cell cavities were made and tested. We will look at the flux expulsion characteristics of each lot, and RF loss of the 9-cell cavities produced using the individual heat lots.

Poster TUP057 [1.446 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP057

About •

paper received ※ 25 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

Export •

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

TUP062

New Insights in the Quench Mechanisms in Nitrogen Doped Cavities

592

D. Bafia, J. Zasadzinski
IIT, Chicago, Illinois, USA
D. Bafia, D.J. Bice, A. Grassellino, O.S. Melnychuk, A.S. Romanenko, D.A. Sergatskov
Fermilab, Batavia, Illinois, USA
D. Gonnella
SLAC, Menlo Park, California, USA
A.D. Palczewski
JLab, Newport News, Virginia, USA

This paper will cover a systematic study of the quench in nitrogen doped cavities: three cavities were sequentially treated/reset with different doping recipes which are known to produce different levels of quench field. Analysis of mean free path and TMAP coupled with sample analysis reveals new insights on the physics of the premature quench in nitrogen doped cavities; new recipes demonstrate the possibility to increase quench fields well beyond 30 MV/m.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-TUP062

About •

paper received ※ 23 June 2019 paper accepted ※ 02 July 2019 issue date ※ 14 August 2019

Export •

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

THP049

Commissioning the JLab LERF Cryomodule Test Facility

973

C. Hovater, R. Bachimanchi, E. Daly, M.A. Drury, L.E. Farrish, J. Gubeli, N.A. Huque, K. Jordan, M.E. Joyce, L.K. King, M. Marchlik, W. Moore, T.E. Plawski, A.D. Solopova, C.M. Wilson
JLab, Newport News, Virginia, USA
A.L. Benwell, C. Bianchini, D. Gonnella, S.L. Hoobler, K.J. Mattison, J. Nelson, A. Ratti, B.H. Ripman, S. Saraf, L.M. Zacarias
SLAC, Menlo Park, California, USA
L.R. Doolittle, S. Paiagua, C. Serrano
LBNL, Berkeley, California, USA

The JLab Low Energy Recirculating Facility, LERF, has been modified to support concurrent testing of two LCLS-II cryomodules. The cryomodules are installed in a similar fashion as they would be in the L1 section of the LCLS-II linac, including the floor slope and using all of the LCLS-II hardware and controls for cryomodule cryogenics, vacuum, and RF (SSA and LLRF). From the start, it was intended to use LCLS-II electronics and EPICS software controls for cryomodule testing. In affect the LERF test facility becomes the first opportunity to commission and operate the LCLS-II LINAC hardware and software controls. Support for specific cryomodule high level test applications like Q₀ and HOMs measurements, are being developed from the basic cryomodule control suite. To support the testing, 2 K He is supplied from the CEBAF south linac cryogenic system, where care must be taken when using the LERF test facility to not upset the CEBAF cryogenics plant. This paper discusses the commissioning of the hardware and software development for testing the first two LCLS-II cryomodules.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP049

About •

paper received ※ 22 June 2019 paper accepted ※ 02 July 2019 issue date ※ 14 August 2019

Export •

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

THP059

RF Incoming Inspection of 1.3 GHz Cryomodules for LCLS-II at SLAC National Accelerator Laboratory

1014

S. Aderhold, C. Adolphsen, A. Burrill, D. Gonnella, J. Nelson
SLAC, Menlo Park, California, USA

Funding: This work was supported by the US DOE and the LCLS-II Project.
The main part of the SRF linac for the Linac Coherent Light Source II (LCLS-II) at SLAC National Accelerator Laboratory will consist of 35 cryomodules with superconducting RF cavities operating at 1.3 GHz. The cryomodules are assembled and tested at Fermi National Accelerator Laboratory and Thomas Jefferson National Accelerator Facility. Following the transport to SLAC, the cryomodules undergo several incoming inspection steps before ultimately being moved to the tunnel for installation in the linac. The RF part of the incoming inspection covers measurements of a number of parameters like cavity frequency spectrum, notch filter frequency of the higher order mode couplers and external quality factor Q_ext of the input coupler. The inspection results are compared to measurements at the partner labs prior to shipping and the nominal values in order to verify that the cryomodules have not been damaged during the transport and are ready for installation. We present an overview and analysis of the inspections for the cryomodules received to date.

Poster THP059 [1.223 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP059

About •

paper received ※ 02 July 2019 paper accepted ※ 02 July 2019 issue date ※ 14 August 2019

Export •

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

FRCAA3

Industrial Cavity Production: Lessons Learned to Push the Boundaries of Nitrogen-Doping

1199

D. Gonnella, S. Aderhold, A. Burrill, M.C. Ross
SLAC, Menlo Park, California, USA
E. Daly, G.K. Davis, F. Marhauser, A.D. Palczewski, K.M. Wilson
JLab, Newport News, Virginia, USA
A. Grassellino, C.J. Grimm, T.N. Khabiboulline, O.S. Melnychuk, S. Posen, D.A. Sergatskov
Fermilab, Batavia, Illinois, USA

Funding: Work supported by US DOE Contract DE-AC02-76SF00515.
Nitrogen doping has been proven now in several labs to enhance Q₀ values of 1.3 GHz cavities in the gradient domain favored by CW operation. The choice of doping for the LCLS-II project has given the community a wealth of statistics and experience on the challenge of transferring the doping technology to industry. Overall, industry-produced nitrogen-doped cavities have shown excellent performance, however some technical issues have arisen. This talk focuses on lessons learned from the production of over 300 nitrogen-doped cavities for LCLS-II and how issues were mitigated to further improve performance. Finally, I will discuss pushing the boundaries of nitrogen-doping further by exploring different doping regimes in order to maintain excellent Q₀ performance, while reaching higher quench fields.

Slides FRCAA3 [16.880 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-FRCAA3

About •

paper received ※ 02 July 2019 paper accepted ※ 03 July 2019 issue date ※ 14 August 2019

Export •

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

FRCAB7

Plasma Processing to Reduce Field Emission in LCLS-II 1.3 GHz SRF Cavities

1231

SUSP022

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

TUP067

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

B. Giaccone, J. Zasadzinski
IIT, Chicago, Illinois, USA
P. Berrutti, B. Giaccone, A. Grassellino, M. Martinello
Fermilab, Batavia, Illinois, USA
M. Doleans
ORNL, Oak Ridge, Tennessee, USA
D. Gonnella, G. Lanza, M.C. Ross
SLAC, Menlo Park, California, USA

Plasma cleaning for LCLS-II 9-cell 1.3 GHz cavities is under study at Fermilab. Starting from ORNL method, we have developed a new technique for plasma ignition using HOMs. Plasma processing is being applied to contaminated and field emitting cavities, here are discussed the first results in terms of Q and radiation vs E measured before and after treatment. Further studies are ongoing to optimize plasma parameters and to acquire statistics on plasma cleaning effectiveness.

Slides FRCAB7 [14.701 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-FRCAB7

About •

paper received ※ 23 June 2019 paper accepted ※ 04 July 2019 issue date ※ 14 August 2019

Export •

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