SRF2021 - List of Authors (Yun, J.C.)

Paper	Title	Page
SUPTEV013	Validation of the 650 MHz SRF Cavity Tuner for PIP-II at 2 K	151
	C. Contreras-Martinez FRIB, East Lansing, Michigan, USA S.K. Chandrasekaran, S. Cheban, G.V. Eremeev, F. Furuta, T.N. Khabiboulline, Y.M. Pischalnikov, O.V. Prokofiev, A.I. Sukhanov, J.C. Yun Fermilab, Batavia, Illinois, USA
	The PIP-II linac will include thirty-six β=0.61 and twenty-four β=0.92 650 MHz 5 cell elliptical SRF cavities. Each cavity will be equipped with a tuning system consisting of a double lever slow tuner for coarse frequency tuning and a piezoelectric actuator for fine frequency tuning. One dressed cavity equipped with an SRF tuner has been tested in the horizontal test stand at Fermilab. Results of testing the cavity-tuner system will be presented.
	Poster SUPTEV013 [0.835 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-SUPTEV013
About •	Received ※ 22 June 2021 — Revised ※ 13 August 2021 — Accepted ※ 26 February 2022 — Issue date ※ 02 May 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

SUPTEV014	SRF Cavity Tuners for 3.9 GHz Cryomodules for LCLS-II Project	155
	C. Contreras-Martinez FRIB, East Lansing, Michigan, USA T.T. Arkan, T.N. Khabiboulline, Y.M. Pischalnikov, G.V. Romanov, R.P. Stanek, J.C. Yun Fermilab, Batavia, Illinois, USA
	Fermilab conducted testing of three 3.9 GHz cryomodules for the LCLS-II project that will operate in continuous wave mode. A fast/fine tuning component was added to the LCLS-II 3.9 GHz tuner design due to the cavity bandwidth of 130 Hz which consists of two encapsulated piezos. Several cavities faced problems with fast-tuner operations after cooldown to 2 K and tuning the cavities to 3.9 GHz in cryomodule 2. All the piezo actuators were in working conditions but the slow tuner ranges required to stretch some of the cavities to the operational 3.9 GHz frequency were too small to deliver the required preload on the piezos. This behavior can be attributed to several factors: setting the initial warm cavity frequency during production too high, pressure tests of the warm cryomodule could have changed cavity frequency; and the small bending and twisting of the cavity-tuner system during the cooldown and warmup of the cavities. A decision was made to inelastically retune the warm cavities to decrease the unrestrained frequency by 200-300 kHz, this was done via the slow tuner. The results for this retuning method of three 3.9GHz cryomodules will be discussed.
	Poster SUPTEV014 [0.720 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-SUPTEV014
About •	Received ※ 22 June 2021 — Accepted ※ 23 January 2022 — Issue date ※ 09 April 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

SUPTEV015	Mitigation of Dielectric Heating of Piezoelectric Actuators at Cryogenic Temperatures	159
	C. Contreras-Martinez FRIB, East Lansing, Michigan, USA Y.M. Pischalnikov, J.C. Yun Fermilab, Batavia, Illinois, USA
	The new generation of low beam intensity superconducting linacs will require high accelerating gradients for new scientific discoveries. The high accelerating gradient cavities in pulsed SRF linacs will experience large (~1000’s of Hz) detuning caused by Lorentz force detuning (LFD). The piezo actuators that will be used to compensate large LFD must operate at a nominal voltage of 120V to 150V to deliver the required stroke to the cavity. In this high voltage range, the piezo is expected to warm up drastically due to its location in an insulating vacuum environment. Overheating of the piezo will significantly decrease the longevity of the actuator. A collaboration between FNAL and Physik Instrumente (PI) developed a novel piezo actuator design that mitigates piezo overheating. The design consists of using a metal foam in contact with the piezoelectric ceramic stack for heat removal. The second solution used lithium niobite as an alternative material. A comparison of the temperature stability will be presented and discussed. This study characterizes the dielectric properties for both materials. The results obtained are in the temperature range of 10 K to 300 K.
	Poster SUPTEV015 [0.733 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-SUPTEV015
About •	Received ※ 22 June 2021 — Revised ※ 13 August 2021 — Accepted ※ 21 October 2021 — Issue date ※ 09 April 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPTEV002	Extended Range SRF Cavity Tuner for LCLS II HE Project	203
	Y.M. Pischalnikov, T.T. Arkan, C.J. Grimm, B.D. Hartsell, J.A. Kaluzny, T.N. Khabiboulline, Y.M. Orlov, J.C. Yun Fermilab, Batavia, Illinois, USA C. Contreras-Martinez FRIB, East Lansing, Michigan, USA
	Funding: This manuscript has been authorized by Fermi Research Alliance LLC under Contract N. DE-AC02-07CH11359 with U.S. Department of Energy. The off-frequency detune method is being considered to be applied in the LCLS-II-HE superconducting linac to produce multi-energy electron beams for supporting multiple undulator lines simultaneously. To deliver off-frequency operation (OFO) requirements for SRF cavity tuner must be changed. Tuner design modifications and results of the testing eight cavity/tuner system, deployed in verification cryomodule (vCM), will be presented.
	Poster MOPTEV002 [0.710 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-MOPTEV002
About •	Received ※ 22 June 2021 — Revised ※ 16 July 2021 — Accepted ※ 19 August 2021 — Issue date ※ 23 September 2021
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPCAV013	STC Qualification Tests of PIP-II HB650 Cavities	465
	A.I. Sukhanov, S.K. Chandrasekaran, G.V. Eremeev, F. Furuta, S. Kazakov, T.N. Khabiboulline, T.H. Nicol, Y.M. Pischalnikov, O.V. Prokofiev, V. Roger, G. Wu, V.P. Yakovlev, J.C. Yun Fermilab, Batavia, Illinois, USA C. Contreras-Martinez FRIB, East Lansing, Michigan, USA
	Design of the high beta 650 MHz prototype cryomodule for PIP-II is currently undergoing at Fermilab. The cryomodule includes six 5-cell elliptical SRF cavities with accelerating voltage up to 20 MV and low heat dissipation (Q₀ > 3.3 · 10^zEhNZeHn). Characterization of performance of fully integrated jacketed cavities with high power coupler and tuner is crucial for the project. Such a characterization of jacketed cavity requires a horizontal test cryostat. The Fermilab Spoke Test Cryostat (STC) has been upgraded to accommodate testing of 650 MHz cavities. Commissioning of upgraded STC has been reported at SRF’19 conference. In this paper we present results of testing of the prototype HB650 cavity in upgraded STC facility. We characterize cavity performance and qualify it for the prototype HB650 cryomodule assembly.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2021-TUPCAV013
About •	Received ※ 21 June 2021 — Accepted ※ 21 August 2021 — Issue date ※ 04 October 2021
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Validation of the 650 MHz SRF Cavity Tuner for PIP-II at 2 K

151

C. Contreras-Martinez
FRIB, East Lansing, Michigan, USA
S.K. Chandrasekaran, S. Cheban, G.V. Eremeev, F. Furuta, T.N. Khabiboulline, Y.M. Pischalnikov, O.V. Prokofiev, A.I. Sukhanov, J.C. Yun
Fermilab, Batavia, Illinois, USA

The PIP-II linac will include thirty-six β=0.61 and twenty-four β=0.92 650 MHz 5 cell elliptical SRF cavities. Each cavity will be equipped with a tuning system consisting of a double lever slow tuner for coarse frequency tuning and a piezoelectric actuator for fine frequency tuning. One dressed cavity equipped with an SRF tuner has been tested in the horizontal test stand at Fermilab. Results of testing the cavity-tuner system will be presented.

Poster SUPTEV013 [0.835 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-SUPTEV013

About •

Received ※ 22 June 2021 — Revised ※ 13 August 2021 — Accepted ※ 26 February 2022 — Issue date ※ 02 May 2022

Cite •

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

SUPTEV014

SRF Cavity Tuners for 3.9 GHz Cryomodules for LCLS-II Project

155

C. Contreras-Martinez
FRIB, East Lansing, Michigan, USA
T.T. Arkan, T.N. Khabiboulline, Y.M. Pischalnikov, G.V. Romanov, R.P. Stanek, J.C. Yun
Fermilab, Batavia, Illinois, USA

Fermilab conducted testing of three 3.9 GHz cryomodules for the LCLS-II project that will operate in continuous wave mode. A fast/fine tuning component was added to the LCLS-II 3.9 GHz tuner design due to the cavity bandwidth of 130 Hz which consists of two encapsulated piezos. Several cavities faced problems with fast-tuner operations after cooldown to 2 K and tuning the cavities to 3.9 GHz in cryomodule 2. All the piezo actuators were in working conditions but the slow tuner ranges required to stretch some of the cavities to the operational 3.9 GHz frequency were too small to deliver the required preload on the piezos. This behavior can be attributed to several factors: setting the initial warm cavity frequency during production too high, pressure tests of the warm cryomodule could have changed cavity frequency; and the small bending and twisting of the cavity-tuner system during the cooldown and warmup of the cavities. A decision was made to inelastically retune the warm cavities to decrease the unrestrained frequency by 200-300 kHz, this was done via the slow tuner. The results for this retuning method of three 3.9GHz cryomodules will be discussed.

Poster SUPTEV014 [0.720 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-SUPTEV014

About •

Received ※ 22 June 2021 — Accepted ※ 23 January 2022 — Issue date ※ 09 April 2022

Cite •

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

SUPTEV015

Mitigation of Dielectric Heating of Piezoelectric Actuators at Cryogenic Temperatures

159

C. Contreras-Martinez
FRIB, East Lansing, Michigan, USA
Y.M. Pischalnikov, J.C. Yun
Fermilab, Batavia, Illinois, USA

The new generation of low beam intensity superconducting linacs will require high accelerating gradients for new scientific discoveries. The high accelerating gradient cavities in pulsed SRF linacs will experience large (~1000’s of Hz) detuning caused by Lorentz force detuning (LFD). The piezo actuators that will be used to compensate large LFD must operate at a nominal voltage of 120V to 150V to deliver the required stroke to the cavity. In this high voltage range, the piezo is expected to warm up drastically due to its location in an insulating vacuum environment. Overheating of the piezo will significantly decrease the longevity of the actuator. A collaboration between FNAL and Physik Instrumente (PI) developed a novel piezo actuator design that mitigates piezo overheating. The design consists of using a metal foam in contact with the piezoelectric ceramic stack for heat removal. The second solution used lithium niobite as an alternative material. A comparison of the temperature stability will be presented and discussed. This study characterizes the dielectric properties for both materials. The results obtained are in the temperature range of 10 K to 300 K.

Poster SUPTEV015 [0.733 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-SUPTEV015

About •

Received ※ 22 June 2021 — Revised ※ 13 August 2021 — Accepted ※ 21 October 2021 — Issue date ※ 09 April 2022

Cite •

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

MOPTEV002

Extended Range SRF Cavity Tuner for LCLS II HE Project

203

Y.M. Pischalnikov, T.T. Arkan, C.J. Grimm, B.D. Hartsell, J.A. Kaluzny, T.N. Khabiboulline, Y.M. Orlov, J.C. Yun
Fermilab, Batavia, Illinois, USA
C. Contreras-Martinez
FRIB, East Lansing, Michigan, USA

Funding: This manuscript has been authorized by Fermi Research Alliance LLC under Contract N. DE-AC02-07CH11359 with U.S. Department of Energy.
The off-frequency detune method is being considered to be applied in the LCLS-II-HE superconducting linac to produce multi-energy electron beams for supporting multiple undulator lines simultaneously. To deliver off-frequency operation (OFO) requirements for SRF cavity tuner must be changed. Tuner design modifications and results of the testing eight cavity/tuner system, deployed in verification cryomodule (vCM), will be presented.

Poster MOPTEV002 [0.710 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-MOPTEV002

About •

Received ※ 22 June 2021 — Revised ※ 16 July 2021 — Accepted ※ 19 August 2021 — Issue date ※ 23 September 2021

Cite •

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

TUPCAV013

STC Qualification Tests of PIP-II HB650 Cavities

465

A.I. Sukhanov, S.K. Chandrasekaran, G.V. Eremeev, F. Furuta, S. Kazakov, T.N. Khabiboulline, T.H. Nicol, Y.M. Pischalnikov, O.V. Prokofiev, V. Roger, G. Wu, V.P. Yakovlev, J.C. Yun
Fermilab, Batavia, Illinois, USA
C. Contreras-Martinez
FRIB, East Lansing, Michigan, USA

Design of the high beta 650 MHz prototype cryomodule for PIP-II is currently undergoing at Fermilab. The cryomodule includes six 5-cell elliptical SRF cavities with accelerating voltage up to 20 MV and low heat dissipation (Q₀ > 3.3 · 10^zEhNZeHn). Characterization of performance of fully integrated jacketed cavities with high power coupler and tuner is crucial for the project. Such a characterization of jacketed cavity requires a horizontal test cryostat. The Fermilab Spoke Test Cryostat (STC) has been upgraded to accommodate testing of 650 MHz cavities. Commissioning of upgraded STC has been reported at SRF’19 conference. In this paper we present results of testing of the prototype HB650 cavity in upgraded STC facility. We characterize cavity performance and qualify it for the prototype HB650 cryomodule assembly.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2021-TUPCAV013

About •

Received ※ 21 June 2021 — Accepted ※ 21 August 2021 — Issue date ※ 04 October 2021

Cite •

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