IPAC2015 - List of Authors (Melnychuk, O.S.)

Paper	Title	Page
WEPTY021	Origin of Trapped Flux Caused by Quench in Superconducting Niobium Cavities	3309
	M. Checchin, A. Grassellino, M. Martinello, O.S. Melnychuk, A. Romanenko, D.A. Sergatskov Fermilab, Batavia, Illinois, USA M. Checchin, M. Martinello Illinois Institute of Technology, Chicago, Illlinois, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. In this study we prove that the mechanism at the basis of quality factor degradation due to quench involves the entrapment of ambient magnetic field. The cavity quench in the absence of magnetic field does not introduce any extra losses, and a clear trend between the external field and the extra losses introduced by the quench was observed. It is demonstrated that the quality factor can be totally recovered by quenching in zero applied magnetic field. A dependence of the amount of quality factor degradation on the orientation of the magnetic field with respect to the cavity was also found.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY021
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WEPTY072	Update on Nitrogen-doped 9-cell Cavity Performance in the Cornell Horizontal Test Cryomodule	3446
	D. Gonnella, R.G. Eichhorn, F. Furuta, G.M. Ge, D.L. Hall, Y. He, K.M.V. Ho, G.H. Hoffstaetter, M. Liepe, J.T. Maniscalco, T.I. O'Connel, S. Posen, P. Quigley, J. Sears, V. Veshcherevich Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA A. Grassellino, C.J. Grimm, O.S. Melnychuk, A. Romanenko Fermilab, Batavia, Illinois, USA
	Funding: U.S. Department of Energy The Linac Coherent Light Source-II (LCLS-II) is a new x-ray source that is planned to be constructed in the existing SLAC tunnel. To meet the quality factor specifications (2.7x 10¹⁰ at 2.0 K and 16 MV/m), nitrogen-doping has been proposed as a preparation method for the SRF cavities. In order to demonstrate the feasibility of these goals, four 9-cell cavity tests have been completed in the Cornell Horizontal Test Cryomodule (HTC), which serves as a test bench for the full LCLS-II cryomodule. Here we report on the most recent two cavity tests in the HTC: one cavity nitrogen-doped at Cornell and tested with high Q input coupler and then again tested with high power LCLS-II input coupler. Transition to test in horizontal cryomodule resulted in no degradation in Q0 from vertical test. Additionally, increased dissipated power due to the high power input coupler was small and in good agreement with simulations. These results represent a crucial step on the way to demonstrating technical readiness for LCLS-II.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY072
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Origin of Trapped Flux Caused by Quench in Superconducting Niobium Cavities

3309

M. Checchin, A. Grassellino, M. Martinello, O.S. Melnychuk, A. Romanenko, D.A. Sergatskov
Fermilab, Batavia, Illinois, USA
M. Checchin, M. Martinello
Illinois Institute of Technology, Chicago, Illlinois, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
In this study we prove that the mechanism at the basis of quality factor degradation due to quench involves the entrapment of ambient magnetic field. The cavity quench in the absence of magnetic field does not introduce any extra losses, and a clear trend between the external field and the extra losses introduced by the quench was observed. It is demonstrated that the quality factor can be totally recovered by quenching in zero applied magnetic field. A dependence of the amount of quality factor degradation on the orientation of the magnetic field with respect to the cavity was also found.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY021

Export •

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

WEPTY072

Update on Nitrogen-doped 9-cell Cavity Performance in the Cornell Horizontal Test Cryomodule

3446

D. Gonnella, R.G. Eichhorn, F. Furuta, G.M. Ge, D.L. Hall, Y. He, K.M.V. Ho, G.H. Hoffstaetter, M. Liepe, J.T. Maniscalco, T.I. O'Connel, S. Posen, P. Quigley, J. Sears, V. Veshcherevich
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
A. Grassellino, C.J. Grimm, O.S. Melnychuk, A. Romanenko
Fermilab, Batavia, Illinois, USA

Funding: U.S. Department of Energy
The Linac Coherent Light Source-II (LCLS-II) is a new x-ray source that is planned to be constructed in the existing SLAC tunnel. To meet the quality factor specifications (2.7x 10¹⁰ at 2.0 K and 16 MV/m), nitrogen-doping has been proposed as a preparation method for the SRF cavities. In order to demonstrate the feasibility of these goals, four 9-cell cavity tests have been completed in the Cornell Horizontal Test Cryomodule (HTC), which serves as a test bench for the full LCLS-II cryomodule. Here we report on the most recent two cavity tests in the HTC: one cavity nitrogen-doped at Cornell and tested with high Q input coupler and then again tested with high power LCLS-II input coupler. Transition to test in horizontal cryomodule resulted in no degradation in Q0 from vertical test. Additionally, increased dissipated power due to the high power input coupler was small and in good agreement with simulations. These results represent a crucial step on the way to demonstrating technical readiness for LCLS-II.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY072

Export •

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