IPAC2016 - List of Authors (Harms, E.R.)

Paper	Title	Page
WEPMR004	Cryomdoule Test Stand Reduced-Magnetic Support Design at Fermilab	2262
	M.W. McGee, S.K. Chandrasekaran, A.C. Crawford, E.R. Harms, J.R. Leibfritz, G. Wu Fermilab, Batavia, Illinois, USA
	Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02- 07CH11359 with the U.S. Department of Energy In a partnership with SLAC National Accelerator Laboratory (SLAC) and Jefferson Lab, Fermilab will assemble and test 17 of the 35 total 1.3 GHz cryomodules for the Linac Coherent Light Source II (LCLS-II) Project. These devices will be tested at Fermilab's Cryomodule Test Facility (CMTF) within the Cryomodule Test Stand (CMTS-1) cave. The problem of magnetic pollution became one of major issues during design stage of the LCLS-II cryomodule as the average quality factor of the accelerating cavities is specified to be 2.7 x 10¹⁰. One of the possible ways to mitigate the effect of stray magnetic fields and to keep it below the goal of 5 mGauss involves the application of low permeable materials. Initial permeability and magnetic measurement studies regarding the use of 316L stainless steel material indicated that cold work (machining) and heat affected zones from welding would be acceptable.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR004
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WEPMR005	Investigation of Thermal Acoustic Effects on SRF Cavities within CM1 at Fermilab	2265
	M.W. McGee, E.R. Harms, A.L. Klebaner, J.R. Leibfritz, A. Martinez, Y.M. Pischalnikov, W. Schappert Fermilab, Batavia, Illinois, USA
	Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02- 07CH11359 with the U.S. Department of Energy. Two TESLA-style 8-cavity cryomodules have been operated at Fermilab Accelerator Science and Technology (FAST), formerly the Superconducting Radio Frequency (SRF) Accelerator Test Facility. Operational instabilities were revealed during Radio Frequency (RF) power studies. These observations were complemented by the characterization of thermal acoustic effects on cavity microphonics manifested by apparent noisy boiling of helium involving vapor bubble and liquid vibration. The thermal acoustic measurements also consider pressure and temperature spikes which drive the phenomenon at low and high frequencies.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR005
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WEPMR011	Simulations and Experimental Studies of Third Harmonic 3.9 Ghz CW Couplers for LCLS-II Project	2280
	N. Solyak, I.V. Gonin, E.R. Harms, S. Kazakov, T.N. Khabiboulline, A. Lunin Fermilab, Batavia, Illinois, USA
	LCLS-II linac is based on SRF technology developed for the XFEL project. The XFEL 3rd harmonic system built by INFN is based on the original designs of cavity and power coupler developed and built by Fermilab for the FLASH facility at DESY. For LCLS-II application both designs of the 3.9 GHz cavity and the power coupler have been modified for an operation in the continuous wave regime up to 2 kW average RF power. In this paper we discuss coupler modifications and the result multiphysics analysis for various operating regimes. For the initial test of a proposed design, we decided to modify two spare warm sections of power couplers, built for the FLASH facility, by shortening both of two inner bellows and making a thicker copper plating. Modification of the existing coupler test stand and the test program are briefly discussed in this paper.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR011
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Paper

Title

Page

Cryomdoule Test Stand Reduced-Magnetic Support Design at Fermilab

2262

M.W. McGee, S.K. Chandrasekaran, A.C. Crawford, E.R. Harms, J.R. Leibfritz, G. Wu
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02- 07CH11359 with the U.S. Department of Energy
In a partnership with SLAC National Accelerator Laboratory (SLAC) and Jefferson Lab, Fermilab will assemble and test 17 of the 35 total 1.3 GHz cryomodules for the Linac Coherent Light Source II (LCLS-II) Project. These devices will be tested at Fermilab's Cryomodule Test Facility (CMTF) within the Cryomodule Test Stand (CMTS-1) cave. The problem of magnetic pollution became one of major issues during design stage of the LCLS-II cryomodule as the average quality factor of the accelerating cavities is specified to be 2.7 x 10¹⁰. One of the possible ways to mitigate the effect of stray magnetic fields and to keep it below the goal of 5 mGauss involves the application of low permeable materials. Initial permeability and magnetic measurement studies regarding the use of 316L stainless steel material indicated that cold work (machining) and heat affected zones from welding would be acceptable.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR004

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WEPMR005

Investigation of Thermal Acoustic Effects on SRF Cavities within CM1 at Fermilab

2265

M.W. McGee, E.R. Harms, A.L. Klebaner, J.R. Leibfritz, A. Martinez, Y.M. Pischalnikov, W. Schappert
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02- 07CH11359 with the U.S. Department of Energy.
Two TESLA-style 8-cavity cryomodules have been operated at Fermilab Accelerator Science and Technology (FAST), formerly the Superconducting Radio Frequency (SRF) Accelerator Test Facility. Operational instabilities were revealed during Radio Frequency (RF) power studies. These observations were complemented by the characterization of thermal acoustic effects on cavity microphonics manifested by apparent noisy boiling of helium involving vapor bubble and liquid vibration. The thermal acoustic measurements also consider pressure and temperature spikes which drive the phenomenon at low and high frequencies.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR005

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

WEPMR011

Simulations and Experimental Studies of Third Harmonic 3.9 Ghz CW Couplers for LCLS-II Project

2280

N. Solyak, I.V. Gonin, E.R. Harms, S. Kazakov, T.N. Khabiboulline, A. Lunin
Fermilab, Batavia, Illinois, USA

LCLS-II linac is based on SRF technology developed for the XFEL project. The XFEL 3rd harmonic system built by INFN is based on the original designs of cavity and power coupler developed and built by Fermilab for the FLASH facility at DESY. For LCLS-II application both designs of the 3.9 GHz cavity and the power coupler have been modified for an operation in the continuous wave regime up to 2 kW average RF power. In this paper we discuss coupler modifications and the result multiphysics analysis for various operating regimes. For the initial test of a proposed design, we decided to modify two spare warm sections of power couplers, built for the FLASH facility, by shortening both of two inner bellows and making a thicker copper plating. Modification of the existing coupler test stand and the test program are briefly discussed in this paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR011

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