SRF2023 - List of Keywords (resonance)

Paper	Title	Other Keywords	Page
MOPMB008	In-Situ Quality Factor Measurements of SRF Cavities at S-DALINAC	cavity, linac, SRF, coupling	70
	R. Grewe, M. Arnold, A. Brauch, M. Dutine, L.E. Jürgensen, N. Pietralla, F. Schließmann, D. Schneider TU Darmstadt, Darmstadt, Germany
	Funding: Work supported by DFG (GRK 2128) and the State of Hesse within the Research Cluster ELEMENTS (Project ID 500/10.006) The Superconducting Darmstadt Linear Accelerator (S-DALINAC) is a thrice recirculating electron accelerator wich can be operated in a multi-turn energy recovery mode. The design parameters for kinetic energy and beam current are up to 130 MeV and up to 20 uA respectively. The injector consists of a six-cell capture cavity and two 20-cell srf cavities. The main linac consists of eight 20-cell cavities. The cavities are operated at a temperature of 2 K with a frequency of 2.9972(1) GHz. Monitoring of the srf cavities is important for the overall performance of the accelerator. A key parameter for the rating of the srf cavity performance is the intrinsic quality factor Q. At the S-DALINAC it is measured for selected cavities during the yearly maintenance procedures. The unique design of the rf input coupler allows for a wide tuning range for the input coupling strength. This makes in-situ quality factor measurements using the decay time measurement method* possible. The contribution illustrates the principal design of the input couplers and the benefits it yields for Q measurements. Recent results including the progression of the quality factors over time will be presented. Felix Schliessmann et al., Nat. Phys. 19, 597-602 (2023). *Tom Powers, Proc. of SRF’05, Cornell University, Ithaca, New York, USA, 2005, p.40.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB008
About •	Received ※ 19 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 04 August 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB026	Measurements of High Values of Dielectric Permittivity Using Transmission Lines	GUI, simulation, higher-order-mode, cavity	447
	V.D. Shemelin, M. Liepe Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: DOE Usage of lossy materials is necessary for absorption of higher order modes excited in the RF cavities. Presently, measurements of lossy materials with usage of transmission lines give errors rapidly increasing with increase of the dielectric permittivity. A method is presented for measurements of high values of dielectric permittivity epsilon in a waveguide at high frequencies with lower errors. This method supplements the method of measurements evolved for low values of epsilon and is close to resonant methods, when a sample is placed into a cavity and the measurement is done at one only frequency. The new approach with use of Microwave Studio simulations makes possible to measure this value in several frequency points at one measurement.
	Poster TUPTB026 [0.872 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB026
About •	Received ※ 20 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 02 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPTB043	Development of 3-Cell Traveling Wave SRF Cavity	cavity, SRF, cryogenics, GUI	517
	F. Furuta, T.N. Khabiboulline, K.E. McGee, V.P. Yakovlev Fermilab, Batavia, Illinois, USA P.V. Avrakhov, R.A. Kostin Euclid TechLabs, Solon, Ohio, 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 Traveling wave SRF cavity is a new technology and requires a multi-stage process for development. Concep-tual designs have been proposed to adopt TW resonance in an SRF cavity The early stages of developments have been funded by several SBIR grants to Euclid Techlabs which were completed in collaboration with Fermilab. A 3-cell proof-of-principle TW cavity was fabricated as part of that and demonstrated the TW resonance excita-tion at room temperature. A TW resonance control tuner for the 3-cell was also fabricated and the preliminary tests were performed. Now, the 3-cell cavity is being processed and prepared for the first cryogenic testing.
	Poster TUPTB043 [1.743 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB043
About •	Received ※ 17 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 02 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWB093	Transportation Fatigue Testing of the pHB650 Power Coupler Antenna for the PIP-II Project at Fermilab	vacuum, SRF, linac, cryomodule	801
	J. Helsper, S.K. Chandrasekaran, J.P. Holzbauer, N. Solyak 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. The PIP-II Project will see international shipment of cryomodules from Europe to the United States, and as such, the shocks which can occur during shipment pose a risk to the internal components. Of particular concern is the coupler ceramic window and surrounding brazes, which can see relatively high stress during an excitation event. Since the antenna design is new, and because of the setback failure would create, a cyclic stress test was devised for the antenna. This paper presents the experimental methods, setup, and results of the test.
	Poster WEPWB093 [2.913 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB093
About •	Received ※ 19 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 03 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWB096	Testing of PIP-II Pre-production 650 MHz Couplers in Warm Test Stand and Cryomodule	vacuum, cavity, cryomodule, coupling	812
	N. Solyak, S.K. Chandrasekaran, B.M. Hanna, J. Helsper, J.P. Holzbauer, S. Kazakov, A.I. Sukhanov Fermilab, Batavia, Illinois, USA
	650 MHz fundamental power couplers were developed for PIP-II project to deliver RF power for low-beta and high-beta elliptical cavities. Few prototypes were built and tested and after some modification we built 8 pre-production couplers (with three spares for vacuum side) for ppHB650 cryomodule. All couplers were successfully tested in pulse mode (up to 100kW) and in CW mode (up to 50kW) in test stand at full reflection at 8 phases. In baseline configuration with DC bias we do not see any multipactoring activity after short processing. We also tested power processing without bias for uncoated and TiN coated ceramic window. Results of these studies presented in this paper. One of the coupler was assembled on LB650 cavity and tested at cryogenic environment in STC cryostat at ~30kW power with full reflection at different reflection phase. We also demonstrated good result from power processing without bias for warm and cold cavity. Six couplers were assembled on HB650 cavities in pre-production cryomodule. Test results from cryomodule qualification is discussing in this paper.
	Poster WEPWB096 [2.748 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB096
About •	Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 17 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWB110	Prevention of Dual-Mode Excitation in 9-Cell Cavities for LCLSII-HE	cavity, controls, feedback, SRF	852
	P.D. Owen JLab, Newport News, Virginia, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177. Dual-Mode Excitation, also referred to as mode-mixing, is a superposition of two pi modes in an SRF cavity. In 9-cell TESLA cavities used for the LCLSII-HE project, the two modes that are commonly excited are the pi mode (1300.2 MHz), and the 7/9 pi mode (1297.8 MHz). During vertical cavity qualification testing, it is regularly observed that emitted power at the frequency of the 7/9 pi mode grows, despite the RF system only driving the pi mode. When this happens, the RF power measurement system is unable to differentiate between the superimposed modes which invalidates any data taken. A new RF control solution prevents the 7/9 pi mode from being excited. A second RF control system is connected to drive the 7/9 pi mode. The loop phase for driving this mode is determined, then shifted by 180 degrees, thus providing a negative feedback to the undesired mode. Because this off-resonance power can be very small, it does not interfere with the high-power measurements of the fundamental pi mode. At Jefferson Lab, we are now able to test a cavity for the LCLSII-HE project with no complications from mode-mixing, which allows for CW processing of high-gradient multipacting.
	Poster WEPWB110 [1.818 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB110
About •	Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 13 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWB134	Study of Different Piezoelectric Material Stroke Displacement at Different Temperatures Using an SRF Cavity	cavity, SRF, experiment, controls	911
	C. Contreras-Martinez, Y.M. Pischalnikov, J.C. Yun Fermilab, Batavia, Illinois, USA
	Piezoelectric actuators are used for resonance control in superconducting linacs. The level of frequency compensation depends on the piezoelectric stroke displacement. In this study, the stroke displacement will be measured with a 1.3 GHz SRF cavity by measuring the frequency shift with respect to the voltage applied. The entire system was submerged in liquid helium. This study characterizes the PZT piezoelectric actuator (P-844K093) and a lithium niobate (P-844B0005) piezoelectric actuator. All these actuators were developed at Physik Instrumente (PI). The piezo-electric displacement was measured at different temperatures.
	Poster WEPWB134 [0.776 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB134
About •	Received ※ 16 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 13 July 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOPMB008

In-Situ Quality Factor Measurements of SRF Cavities at S-DALINAC

cavity, linac, SRF, coupling

70

R. Grewe, M. Arnold, A. Brauch, M. Dutine, L.E. Jürgensen, N. Pietralla, F. Schließmann, D. Schneider
TU Darmstadt, Darmstadt, Germany

Funding: Work supported by DFG (GRK 2128) and the State of Hesse within the Research Cluster ELEMENTS (Project ID 500/10.006)
The Superconducting Darmstadt Linear Accelerator (S-DALINAC) is a thrice recirculating electron accelerator wich can be operated in a multi-turn energy recovery mode*. The design parameters for kinetic energy and beam current are up to 130 MeV and up to 20 uA respectively. The injector consists of a six-cell capture cavity and two 20-cell srf cavities. The main linac consists of eight 20-cell cavities. The cavities are operated at a temperature of 2 K with a frequency of 2.9972(1) GHz. Monitoring of the srf cavities is important for the overall performance of the accelerator. A key parameter for the rating of the srf cavity performance is the intrinsic quality factor Q. At the S-DALINAC it is measured for selected cavities during the yearly maintenance procedures. The unique design of the rf input coupler allows for a wide tuning range for the input coupling strength. This makes in-situ quality factor measurements using the decay time measurement method** possible. The contribution illustrates the principal design of the input couplers and the benefits it yields for Q measurements. Recent results including the progression of the quality factors over time will be presented.
*Felix Schliessmann et al., Nat. Phys. 19, 597-602 (2023).
**Tom Powers, Proc. of SRF’05, Cornell University, Ithaca, New York, USA, 2005, p.40.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-MOPMB008

About •

Received ※ 19 June 2023 — Revised ※ 22 June 2023 — Accepted ※ 28 June 2023 — Issue date ※ 04 August 2023

Cite •

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

TUPTB026

Measurements of High Values of Dielectric Permittivity Using Transmission Lines

GUI, simulation, higher-order-mode, cavity

447

V.D. Shemelin, M. Liepe
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: DOE
Usage of lossy materials is necessary for absorption of higher order modes excited in the RF cavities. Presently, measurements of lossy materials with usage of transmission lines give errors rapidly increasing with increase of the dielectric permittivity. A method is presented for measurements of high values of dielectric permittivity epsilon in a waveguide at high frequencies with lower errors. This method supplements the method of measurements evolved for low values of epsilon and is close to resonant methods, when a sample is placed into a cavity and the measurement is done at one only frequency. The new approach with use of Microwave Studio simulations makes possible to measure this value in several frequency points at one measurement.

Poster TUPTB026 [0.872 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB026

About •

Received ※ 20 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 02 July 2023

Cite •

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

TUPTB043

Development of 3-Cell Traveling Wave SRF Cavity

cavity, SRF, cryogenics, GUI

517

F. Furuta, T.N. Khabiboulline, K.E. McGee, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA
P.V. Avrakhov, R.A. Kostin
Euclid TechLabs, Solon, Ohio, 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
Traveling wave SRF cavity is a new technology and requires a multi-stage process for development. Concep-tual designs have been proposed to adopt TW resonance in an SRF cavity The early stages of developments have been funded by several SBIR grants to Euclid Techlabs which were completed in collaboration with Fermilab. A 3-cell proof-of-principle TW cavity was fabricated as part of that and demonstrated the TW resonance excita-tion at room temperature. A TW resonance control tuner for the 3-cell was also fabricated and the preliminary tests were performed. Now, the 3-cell cavity is being processed and prepared for the first cryogenic testing.

Poster TUPTB043 [1.743 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-TUPTB043

About •

Received ※ 17 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 02 July 2023

Cite •

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

WEPWB093

Transportation Fatigue Testing of the pHB650 Power Coupler Antenna for the PIP-II Project at Fermilab

vacuum, SRF, linac, cryomodule

801

J. Helsper, S.K. Chandrasekaran, J.P. Holzbauer, N. Solyak
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.
The PIP-II Project will see international shipment of cryomodules from Europe to the United States, and as such, the shocks which can occur during shipment pose a risk to the internal components. Of particular concern is the coupler ceramic window and surrounding brazes, which can see relatively high stress during an excitation event. Since the antenna design is new, and because of the setback failure would create, a cyclic stress test was devised for the antenna. This paper presents the experimental methods, setup, and results of the test.

Poster WEPWB093 [2.913 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB093

About •

Received ※ 19 June 2023 — Revised ※ 27 June 2023 — Accepted ※ 29 June 2023 — Issue date ※ 03 July 2023

Cite •

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

WEPWB096

Testing of PIP-II Pre-production 650 MHz Couplers in Warm Test Stand and Cryomodule

vacuum, cavity, cryomodule, coupling

812

N. Solyak, S.K. Chandrasekaran, B.M. Hanna, J. Helsper, J.P. Holzbauer, S. Kazakov, A.I. Sukhanov
Fermilab, Batavia, Illinois, USA

650 MHz fundamental power couplers were developed for PIP-II project to deliver RF power for low-beta and high-beta elliptical cavities. Few prototypes were built and tested and after some modification we built 8 pre-production couplers (with three spares for vacuum side) for ppHB650 cryomodule. All couplers were successfully tested in pulse mode (up to 100kW) and in CW mode (up to 50kW) in test stand at full reflection at 8 phases. In baseline configuration with DC bias we do not see any multipactoring activity after short processing. We also tested power processing without bias for uncoated and TiN coated ceramic window. Results of these studies presented in this paper. One of the coupler was assembled on LB650 cavity and tested at cryogenic environment in STC cryostat at ~30kW power with full reflection at different reflection phase. We also demonstrated good result from power processing without bias for warm and cold cavity. Six couplers were assembled on HB650 cavities in pre-production cryomodule. Test results from cryomodule qualification is discussing in this paper.

Poster WEPWB096 [2.748 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB096

About •

Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 17 July 2023

Cite •

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

WEPWB110

Prevention of Dual-Mode Excitation in 9-Cell Cavities for LCLSII-HE

cavity, controls, feedback, SRF

852

P.D. Owen
JLab, Newport News, Virginia, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
Dual-Mode Excitation, also referred to as mode-mixing, is a superposition of two pi modes in an SRF cavity. In 9-cell TESLA cavities used for the LCLSII-HE project, the two modes that are commonly excited are the pi mode (1300.2 MHz), and the 7/9 pi mode (1297.8 MHz). During vertical cavity qualification testing, it is regularly observed that emitted power at the frequency of the 7/9 pi mode grows, despite the RF system only driving the pi mode. When this happens, the RF power measurement system is unable to differentiate between the superimposed modes which invalidates any data taken. A new RF control solution prevents the 7/9 pi mode from being excited. A second RF control system is connected to drive the 7/9 pi mode. The loop phase for driving this mode is determined, then shifted by 180 degrees, thus providing a negative feedback to the undesired mode. Because this off-resonance power can be very small, it does not interfere with the high-power measurements of the fundamental pi mode. At Jefferson Lab, we are now able to test a cavity for the LCLSII-HE project with no complications from mode-mixing, which allows for CW processing of high-gradient multipacting.

Poster WEPWB110 [1.818 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB110

About •

Received ※ 19 June 2023 — Revised ※ 25 June 2023 — Accepted ※ 26 June 2023 — Issue date ※ 13 July 2023

Cite •

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

WEPWB134

Study of Different Piezoelectric Material Stroke Displacement at Different Temperatures Using an SRF Cavity

cavity, SRF, experiment, controls

911

C. Contreras-Martinez, Y.M. Pischalnikov, J.C. Yun
Fermilab, Batavia, Illinois, USA

Piezoelectric actuators are used for resonance control in superconducting linacs. The level of frequency compensation depends on the piezoelectric stroke displacement. In this study, the stroke displacement will be measured with a 1.3 GHz SRF cavity by measuring the frequency shift with respect to the voltage applied. The entire system was submerged in liquid helium. This study characterizes the PZT piezoelectric actuator (P-844K093) and a lithium niobate (P-844B0005) piezoelectric actuator. All these actuators were developed at Physik Instrumente (PI). The piezo-electric displacement was measured at different temperatures.

Poster WEPWB134 [0.776 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SRF2023-WEPWB134

About •

Received ※ 16 June 2023 — Revised ※ 24 June 2023 — Accepted ※ 27 June 2023 — Issue date ※ 13 July 2023

Cite •

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