2011 Particle Accelerator Conference - List of Authors (Sergatskov, D.A.)

Paper

Title

Page

Quench Dynamics in SRF Cavities: Can We Locate the Quench Origin with 2nd Sound?

883

Y.B. Maximenko
MIPT, Dolgoprudniy, Moscow Region, Russia
D.A. Sergatskov
Fermilab, Batavia, USA

A newly developed method of locating quench in SRF cavities by detecting second-sound waves has been gaining popularity in SRF laboratories. The technique is based on measurements of time delays between the quench, as determined by the RF system, and arrival of the 2nd sound wave to the multiple detectors placed around the cavity in superfluid helium. Unlike multi-channel temperature mapping, this approach requires only few sensors and simple readout electronics; it can be used with SRF cavities of almost arbitrary shape. One of its drawbacks is that being an indirect method it requires one to solve an inverse problem to find a location of a quench. We tried to solve this inverse problem by using a parametric forward model. By analyzing the data we found that a simple model where 2nd-sound emitter is a near-singular source does not describe the physical system well enough. A time-dependent analysis of a quench process can help us to put forward a more adequate model. We present here our current algorithm to solve the inverse problem and discuss the experimental results.

TUP076

First High Power Pulsed Tests of a Dressed 325 MHz Superconducting Single Spoke Resonator at Fermilab

964

R.L. Madrak, J. Branlard, B. Chase, C. Darve, P.W. Joireman, T.N. Khabiboulline, A. Mukherjee, T.H. Nicol, E. Peoples-Evans, D.W. Peterson, Y.M. Pischalnikov, L. Ristori, W. Schappert, D.A. Sergatskov, W.M. Soyars, J. Steimel, I. Terechkine, V. Tupikov, R.L. Wagner, R.C. Webber, D. Wildman
Fermilab, Batavia, USA

In the recently commissioned superconducting RF cavity test facility at Fermilab (SCTF), a 325 MHz, β=0.22 superconducting single-spoke resonator (SSR1) has been tested for the first time with its input power coupler. Previously, this cavity had been tested CW with a low power, high Qext test coupler; first as a bare cavity in the Fermilab Vertical Test Stand and then fully dressed in the SCTF. For the tests described here, the design input coupler with Q_ext ~ 10⁶ was used. Pulsed power was provided by a Toshiba E3740A 2.5 MW klystron.

FROBS5

1.3 GHz Superconducting RF Cavity Program at Fermilab

2586

C.M. Ginsburg, T.T. Arkan, S. Barbanotti, H. Carter, M.S. Champion, L.D. Cooley, C.A. Cooper, M.H. Foley, M. Ge, C.J. Grimm, E.R. Harms, A. Hocker, R.D. Kephart, T.N. Khabiboulline, J.R. Leibfritz, A. Lunin, J.P. Ozelis, Y.M. Pischalnikov, A.M. Rowe, W. Schappert, D.A. Sergatskov, A.I. Sukhanov, G. Wu
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC under contract DE-AC02-07CH11359 with the U.S. Department of Energy.
At Fermilab, 9-cell 1.3 GHz superconducting RF (SRF) cavities are prepared, qualified, and assembled into cryomodules, for Project X, an International Linear Collider, or other future projects. The 1.3 GHz SRF cavity program includes targeted R&D on 1-cell 1.3 GHz cavities for cavity performance improvement. Production cavity qualification includes cavity inspection, surface processing, clean assembly, and one or more cryogenic low-power CW qualification tests which typically include performance diagnostics. Qualified cavities are welded into helium vessels and are cryogenically tested with pulsed high-power. Well performing cavities are assembled into cryomodules for pulsed high-power testing in a cryomodule test facility, and possible installation into a beamline. The overall goals of the 1.3 GHz SRF cavity program, supporting facilities, and accomplishments are described.

Slides FROBS5 [3.749 MB]

Paper	Title	Page
TUP041	Quench Dynamics in SRF Cavities: Can We Locate the Quench Origin with 2nd Sound?	883
	Y.B. Maximenko MIPT, Dolgoprudniy, Moscow Region, Russia D.A. Sergatskov Fermilab, Batavia, USA
	A newly developed method of locating quench in SRF cavities by detecting second-sound waves has been gaining popularity in SRF laboratories. The technique is based on measurements of time delays between the quench, as determined by the RF system, and arrival of the 2nd sound wave to the multiple detectors placed around the cavity in superfluid helium. Unlike multi-channel temperature mapping, this approach requires only few sensors and simple readout electronics; it can be used with SRF cavities of almost arbitrary shape. One of its drawbacks is that being an indirect method it requires one to solve an inverse problem to find a location of a quench. We tried to solve this inverse problem by using a parametric forward model. By analyzing the data we found that a simple model where 2nd-sound emitter is a near-singular source does not describe the physical system well enough. A time-dependent analysis of a quench process can help us to put forward a more adequate model. We present here our current algorithm to solve the inverse problem and discuss the experimental results.

TUP076	First High Power Pulsed Tests of a Dressed 325 MHz Superconducting Single Spoke Resonator at Fermilab	964
	R.L. Madrak, J. Branlard, B. Chase, C. Darve, P.W. Joireman, T.N. Khabiboulline, A. Mukherjee, T.H. Nicol, E. Peoples-Evans, D.W. Peterson, Y.M. Pischalnikov, L. Ristori, W. Schappert, D.A. Sergatskov, W.M. Soyars, J. Steimel, I. Terechkine, V. Tupikov, R.L. Wagner, R.C. Webber, D. Wildman Fermilab, Batavia, USA
	In the recently commissioned superconducting RF cavity test facility at Fermilab (SCTF), a 325 MHz, β=0.22 superconducting single-spoke resonator (SSR1) has been tested for the first time with its input power coupler. Previously, this cavity had been tested CW with a low power, high Qext test coupler; first as a bare cavity in the Fermilab Vertical Test Stand and then fully dressed in the SCTF. For the tests described here, the design input coupler with Q_ext ~ 10⁶ was used. Pulsed power was provided by a Toshiba E3740A 2.5 MW klystron.

FROBS5	1.3 GHz Superconducting RF Cavity Program at Fermilab	2586
	C.M. Ginsburg, T.T. Arkan, S. Barbanotti, H. Carter, M.S. Champion, L.D. Cooley, C.A. Cooper, M.H. Foley, M. Ge, C.J. Grimm, E.R. Harms, A. Hocker, R.D. Kephart, T.N. Khabiboulline, J.R. Leibfritz, A. Lunin, J.P. Ozelis, Y.M. Pischalnikov, A.M. Rowe, W. Schappert, D.A. Sergatskov, A.I. Sukhanov, G. Wu Fermilab, Batavia, USA
	Funding: Work supported by Fermi Research Alliance, LLC under contract DE-AC02-07CH11359 with the U.S. Department of Energy. At Fermilab, 9-cell 1.3 GHz superconducting RF (SRF) cavities are prepared, qualified, and assembled into cryomodules, for Project X, an International Linear Collider, or other future projects. The 1.3 GHz SRF cavity program includes targeted R&D on 1-cell 1.3 GHz cavities for cavity performance improvement. Production cavity qualification includes cavity inspection, surface processing, clean assembly, and one or more cryogenic low-power CW qualification tests which typically include performance diagnostics. Qualified cavities are welded into helium vessels and are cryogenically tested with pulsed high-power. Well performing cavities are assembled into cryomodules for pulsed high-power testing in a cryomodule test facility, and possible installation into a beamline. The overall goals of the 1.3 GHz SRF cavity program, supporting facilities, and accomplishments are described.
	Slides FROBS5 [3.749 MB]