SRF2021 - Table of Session: THPFDV (Thursday Poster Fundamental Development and Research)

Paper	Title	Page
THPFDV001	Status of the New Quadrupole Resonator for SRF R&D	751
	R. Monroy-Villa, W. Hillert, M. Wenskat University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany S. Gorgi Zadeh, P. Putek Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany M. Lemke, R. Monroy-Villa, D. Reschke, M. Röhling, J.H. Thie DESY, Hamburg, Germany
	A basic understanding of the properties of SRF samples under surface treatments would aid in the development of consistent theories. To study the RF properties of such samples under realistic superconducting-cavity-like conditions, a test device called Quadrupole Resonator (QPR) was fabricated. In this publication we report the status of the QPR at Universität Hamburg in collaboration with DESY. Our device is based on the QPRs operated at CERN and at HZB, and its design will allow for testing samples at temperatures between 2 K and 8 K, under magnetic fields up to 120 mT and with operating frequencies of 433 MHz, 866 MHz and 1300 MHz. Fabrication tolerance studies on the electromagnetic field distributions and simulations of the static detuning of the device, together with the commissioning report and the ongoing surface treatment, will be presented.
	Poster THPFDV001 [1.074 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-THPFDV001
About •	Received ※ 27 June 2021 — Revised ※ 23 August 2021 — Accepted ※ 23 August 2021 — Issue date ※ 29 April 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPFDV002	The Influence of Irradiation on the Current Carrying Phenomena in HTc Multilayered Superconductors	756
	J. Sosnowski NCBJ, Świerk/Otwock, Poland
	Paper is devoted to analysis of the influence of irradiation arising in SRF accelerators on critical current phenomena of HTc multilayered superconductors. Impact of size and concentration of created then nano-defects on current-voltage characteristics and critical current of HTc superconductors as function of the magnetic field and temperature will be investigated. It will be studied basing on analysis of interaction of the magnetic pancake vortices with arising during irradiation defects, for various strengths of capturing. The comparison of the model with experimental data will be given too. The dynamic losses dependent on critical current, generated in the superconducting current leads for varying current, will be considered. Analysis of the dynamic magnetic induction distribution inside superconducting lead for time varying current in the cycle will be given and Joule losses estimated. As the result it has been established the hysteresis behavior of the losses in current leads. The changes of losses have been observed for first and following current increase, which effect should have meaning during multiply charging of the superconducting electromagnets.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-THPFDV002
About •	Received ※ 16 June 2021 — Revised ※ 10 August 2021 — Accepted ※ 23 November 2021 — Issue date ※ 02 March 2022
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THPFDV003	SIMS Investigation of Furnace-Baked Nb	761
	E.M. Lechner, M.J. Kelley, A.D. Palczewski, C.E. Reece JLab, Newport News, Virginia, USA J.W. Angle, M.J. Kelley Virginia Polytechnic Institute and State University, Blacksburg, USA F.A. Stevie NCSU AIF, Raleigh, North Carolina, USA
	Funding: U.S. DOE Contract No. DE-AC05-06OR23177 Results recently published by Ito et al. showed that "furnace baking" Nb SRF cavities after electropolishing yields high quality factors and anti-Q-slopes resembling that of N doped cavities. Small Nb samples were prepared following the recipe outlined by Ito. These samples were measured by SIMS to examine impurity contributions to the RF penetration layer. These diffusion profiles are modeled, and their consequences on RF properties discussed.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-THPFDV003
About •	Received ※ 22 June 2021 — Accepted ※ 24 November 2021 — Issue date ※ 15 May 2022
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THPFDV005	Superconducting RF Performance of Cornell 500 MHz N-Doped B-Cell SRF Cavitiy	764
	M. Ge, T. Gruber, A.T. Holic, M. Liepe, J. Sears Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	The Cornell SRF group is working on rebuilding a 500 MHz B-cell cryomodule (CRYO-2 BB1-5) as a spared cryomodule for the operation of the CESR ring. To minimize BCS surface resistance, achieve a high quality-factor (Q₀), and increase maximum fields, we prepared the cavity’s surface with electropolishing and performed a 2/6 N2-doping. In this work, we report 4.2 K and 2 K cavity test results with detailed surface resistance analysis, showing improved performance, including significant higher fields.
	Poster THPFDV005 [0.718 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-THPFDV005
About •	Received ※ 05 July 2021 — Revised ※ 10 August 2021 — Accepted ※ 21 August 2021 — Issue date ※ 22 April 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPFDV006	Seebeck Coefficient Measurement at Cryogenic Temperatures for the LCLS-II HE Project	768
	M. Ge, A.T. Holic, M. Liepe, J. Sears Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Reducing thermoelectric currents during cooldown is important to maintain high-quality factors (Q₀) of the cavities in the LCLS-II HE cryomodules. The temperature-dependent Seebeck coefficients of the materials used in the cryomodules are needed for quantitative estimations of thermoelectric currents. In this work, we present a setup for cryogenic Seebeck coefficient measurements as well as the measured Seebeck coefficients of high-pure niobium at cryogenic temperatures between 4K and 200K.
	Poster THPFDV006 [0.511 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-THPFDV006
About •	Received ※ 29 June 2021 — Revised ※ 10 August 2021 — Accepted ※ 21 August 2021 — Issue date ※ 26 November 2021
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THPFDV008	Research on Ceramic for RF Window	771
	Y. Yamamoto, K. Nakamura, H. Yoshizumi Kyocera Corporation, Corporate Fine Ceramics Group, Kyoto, Japan S. Michizono, Y. Yamamoto KEK, Ibaraki, Japan
	Kyocera and KEK had started joint research on developing materials that satisfy the required characteristics as RF window materials. In previous studies, AO479B was developed, and it has been applied to some products. However, AO479B has size limitation in applying to products. Recently, large RF windows is demanded. Therefore, we have developed a new material AO479U which is designed to be applied to products regardless of the product size. In this report, the characteristics of AO479U was evaluated by comparing it with other materials, including the presence or absence of TiN coating. In order to clarify how the differences of materials or manufacturing processes contributes to heat generation and multipactor discharge occurring in RF windows, we measured important characteristics as RF window materials (relative permittivity, dielectric loss tangent, surface resistance, volume resistivity, secondary electron emission coefficient, and TiN thickness), and investigated the relationships of them and materials or manufacturing processes.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-THPFDV008
About •	Received ※ 18 June 2021 — Revised ※ 06 December 2021 — Accepted ※ 28 February 2022 — Issue date ※ 01 May 2022
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Paper

Title

Page

Status of the New Quadrupole Resonator for SRF R&D

751

R. Monroy-Villa, W. Hillert, M. Wenskat
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
S. Gorgi Zadeh, P. Putek
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
M. Lemke, R. Monroy-Villa, D. Reschke, M. Röhling, J.H. Thie
DESY, Hamburg, Germany

A basic understanding of the properties of SRF samples under surface treatments would aid in the development of consistent theories. To study the RF properties of such samples under realistic superconducting-cavity-like conditions, a test device called Quadrupole Resonator (QPR) was fabricated. In this publication we report the status of the QPR at Universität Hamburg in collaboration with DESY. Our device is based on the QPRs operated at CERN and at HZB, and its design will allow for testing samples at temperatures between 2 K and 8 K, under magnetic fields up to 120 mT and with operating frequencies of 433 MHz, 866 MHz and 1300 MHz. Fabrication tolerance studies on the electromagnetic field distributions and simulations of the static detuning of the device, together with the commissioning report and the ongoing surface treatment, will be presented.

Poster THPFDV001 [1.074 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-THPFDV001

About •

Received ※ 27 June 2021 — Revised ※ 23 August 2021 — Accepted ※ 23 August 2021 — Issue date ※ 29 April 2022

Cite •

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

THPFDV002

The Influence of Irradiation on the Current Carrying Phenomena in HTc Multilayered Superconductors

756

J. Sosnowski
NCBJ, Świerk/Otwock, Poland

Paper is devoted to analysis of the influence of irradiation arising in SRF accelerators on critical current phenomena of HTc multilayered superconductors. Impact of size and concentration of created then nano-defects on current-voltage characteristics and critical current of HTc superconductors as function of the magnetic field and temperature will be investigated. It will be studied basing on analysis of interaction of the magnetic pancake vortices with arising during irradiation defects, for various strengths of capturing. The comparison of the model with experimental data will be given too. The dynamic losses dependent on critical current, generated in the superconducting current leads for varying current, will be considered. Analysis of the dynamic magnetic induction distribution inside superconducting lead for time varying current in the cycle will be given and Joule losses estimated. As the result it has been established the hysteresis behavior of the losses in current leads. The changes of losses have been observed for first and following current increase, which effect should have meaning during multiply charging of the superconducting electromagnets.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-THPFDV002

About •

Received ※ 16 June 2021 — Revised ※ 10 August 2021 — Accepted ※ 23 November 2021 — Issue date ※ 02 March 2022

Cite •

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

THPFDV003

SIMS Investigation of Furnace-Baked Nb

761

E.M. Lechner, M.J. Kelley, A.D. Palczewski, C.E. Reece
JLab, Newport News, Virginia, USA
J.W. Angle, M.J. Kelley
Virginia Polytechnic Institute and State University, Blacksburg, USA
F.A. Stevie
NCSU AIF, Raleigh, North Carolina, USA

Funding: U.S. DOE Contract No. DE-AC05-06OR23177
Results recently published by Ito et al. showed that "furnace baking" Nb SRF cavities after electropolishing yields high quality factors and anti-Q-slopes resembling that of N doped cavities. Small Nb samples were prepared following the recipe outlined by Ito. These samples were measured by SIMS to examine impurity contributions to the RF penetration layer. These diffusion profiles are modeled, and their consequences on RF properties discussed.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-THPFDV003

About •

Received ※ 22 June 2021 — Accepted ※ 24 November 2021 — Issue date ※ 15 May 2022

Cite •

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

THPFDV005

Superconducting RF Performance of Cornell 500 MHz N-Doped B-Cell SRF Cavitiy

764

M. Ge, T. Gruber, A.T. Holic, M. Liepe, J. Sears
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

The Cornell SRF group is working on rebuilding a 500 MHz B-cell cryomodule (CRYO-2 BB1-5) as a spared cryomodule for the operation of the CESR ring. To minimize BCS surface resistance, achieve a high quality-factor (Q₀), and increase maximum fields, we prepared the cavity’s surface with electropolishing and performed a 2/6 N2-doping. In this work, we report 4.2 K and 2 K cavity test results with detailed surface resistance analysis, showing improved performance, including significant higher fields.

Poster THPFDV005 [0.718 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-THPFDV005

About •

Received ※ 05 July 2021 — Revised ※ 10 August 2021 — Accepted ※ 21 August 2021 — Issue date ※ 22 April 2022

Cite •

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

THPFDV006

Seebeck Coefficient Measurement at Cryogenic Temperatures for the LCLS-II HE Project

768

M. Ge, A.T. Holic, M. Liepe, J. Sears
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Reducing thermoelectric currents during cooldown is important to maintain high-quality factors (Q₀) of the cavities in the LCLS-II HE cryomodules. The temperature-dependent Seebeck coefficients of the materials used in the cryomodules are needed for quantitative estimations of thermoelectric currents. In this work, we present a setup for cryogenic Seebeck coefficient measurements as well as the measured Seebeck coefficients of high-pure niobium at cryogenic temperatures between 4K and 200K.

Poster THPFDV006 [0.511 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-THPFDV006

About •

Received ※ 29 June 2021 — Revised ※ 10 August 2021 — Accepted ※ 21 August 2021 — Issue date ※ 26 November 2021

Cite •

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

THPFDV008

Research on Ceramic for RF Window

771

Y. Yamamoto, K. Nakamura, H. Yoshizumi
Kyocera Corporation, Corporate Fine Ceramics Group, Kyoto, Japan
S. Michizono, Y. Yamamoto
KEK, Ibaraki, Japan

Kyocera and KEK had started joint research on developing materials that satisfy the required characteristics as RF window materials. In previous studies, AO479B was developed, and it has been applied to some products. However, AO479B has size limitation in applying to products. Recently, large RF windows is demanded. Therefore, we have developed a new material AO479U which is designed to be applied to products regardless of the product size. In this report, the characteristics of AO479U was evaluated by comparing it with other materials, including the presence or absence of TiN coating. In order to clarify how the differences of materials or manufacturing processes contributes to heat generation and multipactor discharge occurring in RF windows, we measured important characteristics as RF window materials (relative permittivity, dielectric loss tangent, surface resistance, volume resistivity, secondary electron emission coefficient, and TiN thickness), and investigated the relationships of them and materials or manufacturing processes.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-THPFDV008

About •

Received ※ 18 June 2021 — Revised ※ 06 December 2021 — Accepted ※ 28 February 2022 — Issue date ※ 01 May 2022

Cite •

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