SRF2019 - List of Authors (Gerigk, F.)

Paper	Title	Page
WETEB7	A Ferroelectric Fast Reactive Tuner for Superconducting Cavities	781
	N.C. Shipman, J. Bastard, M.R. Coly, F. Gerigk, A. Macpherson, N. Stapley CERN, Meyrin, Switzerland I. Ben-Zvi BNL, Upton, New York, USA G. Burt, A. Castilla Lancaster University, Lancaster, United Kingdom C.-J. Jing, A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA S. Kazakov Fermilab, Batavia, Illinois, USA E. Nenasheva Ceramics Ltd., St. Petersburg, Russia
	A prototype FerroElectric Fast Reactive Tuner (FE-FRT) for superconducting cavities has been developed, which allows the frequency to be controlled by application of a potential difference across a ferroelectric residing within the tuner. This technique has now become practically feasible due to the recent development of a new extremely low loss ferroelectric material. In a world first, CERN has tested the prototype FE-FRT with a superconducting cavity, and frequency tuning has been successfully demonstrated. This is a significant first step in the development of an entirely new class of tuner. These will allow electronic control of cavity frequencies, by a device operating at room temperature, within timescales that will allow active compensation of microphonics. For many applications this could eliminate the need to use over-coupled fundamental power couplers, thus significantly reducing RF amplifier power.
	Slides WETEB7 [21.570 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-WETEB7
About •	paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THP031	Operation Experience with the LHC ACS RF System	911
	K. Turaj, L. Arnaudon, P. Baudrenghien, O. Brunner, A.C. Butterworth, F. Gerigk, M. Karppinen, P. Maesen, E. Montesinos, F. Peauger, G.J. Rosaz, E.N. Shaposhnikova, D. Smekens, M. Taborelli, M. Therasse, H. Timko, D. Valuch, N. Valverde Alonso, W. Venturini Delsolaro CERN, Meyrin, Switzerland
	The LHC accelerating RF system consists of two cryomodules per beam, each containing four single-cell niobium sputtered 400.8 MHz superconducting cavities working at 4.5 K and an average accelerating voltage of 2 MV. The paper summarises the experience, availability and evolution of the system within 10 years of operation. The lessons learned from the successful replacement and re-commissioning of one cryomodule with a spare module, and the recent re-test of the originally installed module on the test stand are also included. Finally, a review of currently launched spare cavity production and long-term developments are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP031
About •	paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THP095	Direct Measurement of Thermoelectric Currents During Cool Down	1139
	A.E. Ivanov, F. Gerigk, A. Macpherson CERN, Geneva, Switzerland
	In recent years there has been much discussion on thermoelectric effects and their role in flux expulsion during cool down of SRF cavities. Magnetic field is often measured to asses both flux expulsion as the cavity undergoes superconducting transition, and thermoelectric currents due to spatial thermal gradients. As a complementary view, in this paper we show direct measurement of the thermoelectric current independent from the expulsion measurement of the magnetic field. In our setup the azimuthally symmetric cavity is vertically installed and the thermal gradient is along the symmetry axis allowing to describe the cool down behavior of the thermoelectric current using simple coupled simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP095
About •	paper received ※ 21 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

A Ferroelectric Fast Reactive Tuner for Superconducting Cavities

781

N.C. Shipman, J. Bastard, M.R. Coly, F. Gerigk, A. Macpherson, N. Stapley
CERN, Meyrin, Switzerland
I. Ben-Zvi
BNL, Upton, New York, USA
G. Burt, A. Castilla
Lancaster University, Lancaster, United Kingdom
C.-J. Jing, A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
S. Kazakov
Fermilab, Batavia, Illinois, USA
E. Nenasheva
Ceramics Ltd., St. Petersburg, Russia

A prototype FerroElectric Fast Reactive Tuner (FE-FRT) for superconducting cavities has been developed, which allows the frequency to be controlled by application of a potential difference across a ferroelectric residing within the tuner. This technique has now become practically feasible due to the recent development of a new extremely low loss ferroelectric material. In a world first, CERN has tested the prototype FE-FRT with a superconducting cavity, and frequency tuning has been successfully demonstrated. This is a significant first step in the development of an entirely new class of tuner. These will allow electronic control of cavity frequencies, by a device operating at room temperature, within timescales that will allow active compensation of microphonics. For many applications this could eliminate the need to use over-coupled fundamental power couplers, thus significantly reducing RF amplifier power.

Slides WETEB7 [21.570 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-WETEB7

About •

paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

Export •

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

THP031

Operation Experience with the LHC ACS RF System

911

K. Turaj, L. Arnaudon, P. Baudrenghien, O. Brunner, A.C. Butterworth, F. Gerigk, M. Karppinen, P. Maesen, E. Montesinos, F. Peauger, G.J. Rosaz, E.N. Shaposhnikova, D. Smekens, M. Taborelli, M. Therasse, H. Timko, D. Valuch, N. Valverde Alonso, W. Venturini Delsolaro
CERN, Meyrin, Switzerland

The LHC accelerating RF system consists of two cryomodules per beam, each containing four single-cell niobium sputtered 400.8 MHz superconducting cavities working at 4.5 K and an average accelerating voltage of 2 MV. The paper summarises the experience, availability and evolution of the system within 10 years of operation. The lessons learned from the successful replacement and re-commissioning of one cryomodule with a spare module, and the recent re-test of the originally installed module on the test stand are also included. Finally, a review of currently launched spare cavity production and long-term developments are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP031

About •

paper received ※ 23 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

Export •

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

THP095

Direct Measurement of Thermoelectric Currents During Cool Down

1139

A.E. Ivanov, F. Gerigk, A. Macpherson
CERN, Geneva, Switzerland

In recent years there has been much discussion on thermoelectric effects and their role in flux expulsion during cool down of SRF cavities. Magnetic field is often measured to asses both flux expulsion as the cavity undergoes superconducting transition, and thermoelectric currents due to spatial thermal gradients. As a complementary view, in this paper we show direct measurement of the thermoelectric current independent from the expulsion measurement of the magnetic field. In our setup the azimuthally symmetric cavity is vertically installed and the thermal gradient is along the symmetry axis allowing to describe the cool down behavior of the thermoelectric current using simple coupled simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP095

About •

paper received ※ 21 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

Export •

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