SRF2013 - List of Keywords (diagnostics)

Paper	Title	Other Keywords	Page
TUP102	Quench Detection Diagnostics on 3.9 GHz XFEL Cavities	cavity, site, detector, superconductivity	710
	M. Bertucci, A. Bosotti, L. Garolfi, P. Michelato, L. Monaco, D. Sertore INFN/LASA, Segrate (MI), Italy C. Pagani Università degli Studi di Milano & INFN, Segrate, Italy
	This paper presents results of quench localization on 3.9 GHz XFEL prototype cavities tested at LASA vertical test facility. Cavities have been equipped with OST second sound detectors and thermometry sensors. A first guess for quench position has been obtained from modal analysis. Second sound sensors confirmed the quench position resolving also the symmetry degeneracy given by the RF mode pattern analysis. In a subsequent vertical test, second sound and temperature sensors have been installed nearby the suspect quench position. From Thermometry mapping, a sudden increase in cavity temperature within a small region is evident, therefore confirming that a local thermal breakdown due to defect heating occurs in the predicted quench point. The quench region deduced with the mentioned techniques is eventually compared with results of optical inspection.

TUP103	Calibration and Characterization of Capacitive OST Quench Detectors in SRF Cavities at IPN Orsay	SRF, detector, cavity, cryogenics	714
	M. Fouaidy, F. Dubois, J.-M. Dufour, D. Longuevergne, A. Maroni, G. Michel, J.-F. Yaniche IPN, Orsay, France
	Funding: IPNO/IPN2P3/CNRS The maximum RF surface magnetic field (Bs) achieved with SRF bulk Nb cavities is often limited by anomalous losses due to Joule heating of normal-resistive defects embedded onto the RF surface. At high BS (e.g Bs>50 mT), the defect temperature increases strongly with BS, leading to a thermal runaway of the cavity or quench. The unloaded quality factor Q0 of the cavity decreases suddenly and strongly due to superconducting to normal state phase transition of the hot spot area. Quench detectors, called Oscillating Superleak Transducer (OST) and sensing 2nd sound events in He II, have been recently used to study quench of SRF cavities. IPN developed his prototypes of OST quench detectors and a test stand for their calibration and characterization in the temperature range T0=1.6 K-2.2 K. This device allows precise and controlled experimental simulation of SRF cavity quench using pulsed heat sources. Experimental runs were performed to study the dynamic response of OST detectors when the heat source is subjected to a time varying heat flux q(t) as function of several parameters (T0, q(t) time structure and density, heat source size) and first experimental data are presented.

THP090	Compact Interlock System for Supratech High Power RF teststand	klystron, focusing, PLC, FPGA	1138
	A. Hamdi, M. Desmons, M. Luong, J. Novo CEA/DSM/IRFU, France F. Ballester CEA, Gif-sur-Yvette, France
	Supratech is a facility at CEA/Saclay that enables tests on superconducting and high power RF components for particle accelerators. The facility comprises a home-made hard tube HV modulator powering up to 95kV-20A at 2.1ms/50Hz and a 700MHz pulsed klystron developed by CPI able to produce RF up to 1MW-2ms/50Hz. A new compact HV and RF interlock system including klystron HV diagnostics has been implemented on Supratech test facility. This paper describes in more detail the klystron interlock system and the results of the first tests.

THP097	Use of Waveguide Probes as Beam position and Tilt Monitoring Diagnostics with Baseline and Alternative Superconducting Deflecting Cavities for the APS Upgrade	cavity, monitoring, dipole, HOM	1155
	X. Sun, G. Decker, G. Wu ANL, Argonne, USA
	Funding: *Work supported by U.S. Department of Energy, Office of Science, under Contract No. DE-AC-02-06CH11357. A set of superconducting deflecting cavities were studied for the APS Upgrade. A TM-mode baseline deflecting cavity design has been developed and prototyped, while an alternative design based on a TE-like mode is being studied. Waveguide field probes associated with the baseline and alternative superconducting deflecting cavities are explored as beam position and tilt monitoring diagnostics. Microwave Studio was used to simulate the technique of detecting the fields excited by a Gaussian bunch passing through the cavities to determine beam position relative to the electrical center. Probes installed on the horizontal midplane in the beam pipe are promising diagnostics for monitoring beam position and tilt in both designs. The probes in the power coupler also work as beam position monitors for the alternative deflecting cavities.

Paper

Title

Other Keywords

Page

TUP102

Quench Detection Diagnostics on 3.9 GHz XFEL Cavities

cavity, site, detector, superconductivity

710

M. Bertucci, A. Bosotti, L. Garolfi, P. Michelato, L. Monaco, D. Sertore
INFN/LASA, Segrate (MI), Italy
C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy

This paper presents results of quench localization on 3.9 GHz XFEL prototype cavities tested at LASA vertical test facility. Cavities have been equipped with OST second sound detectors and thermometry sensors. A first guess for quench position has been obtained from modal analysis. Second sound sensors confirmed the quench position resolving also the symmetry degeneracy given by the RF mode pattern analysis. In a subsequent vertical test, second sound and temperature sensors have been installed nearby the suspect quench position. From Thermometry mapping, a sudden increase in cavity temperature within a small region is evident, therefore confirming that a local thermal breakdown due to defect heating occurs in the predicted quench point. The quench region deduced with the mentioned techniques is eventually compared with results of optical inspection.

TUP103

Calibration and Characterization of Capacitive OST Quench Detectors in SRF Cavities at IPN Orsay

SRF, detector, cavity, cryogenics

714

M. Fouaidy, F. Dubois, J.-M. Dufour, D. Longuevergne, A. Maroni, G. Michel, J.-F. Yaniche
IPN, Orsay, France

Funding: IPNO/IPN2P3/CNRS
The maximum RF surface magnetic field (Bs) achieved with SRF bulk Nb cavities is often limited by anomalous losses due to Joule heating of normal-resistive defects embedded onto the RF surface. At high BS (e.g Bs>50 mT), the defect temperature increases strongly with BS, leading to a thermal runaway of the cavity or quench. The unloaded quality factor Q0 of the cavity decreases suddenly and strongly due to superconducting to normal state phase transition of the hot spot area. Quench detectors, called Oscillating Superleak Transducer (OST) and sensing 2nd sound events in He II, have been recently used to study quench of SRF cavities. IPN developed his prototypes of OST quench detectors and a test stand for their calibration and characterization in the temperature range T0=1.6 K-2.2 K. This device allows precise and controlled experimental simulation of SRF cavity quench using pulsed heat sources. Experimental runs were performed to study the dynamic response of OST detectors when the heat source is subjected to a time varying heat flux q(t) as function of several parameters (T0, q(t) time structure and density, heat source size) and first experimental data are presented.

THP090

Compact Interlock System for Supratech High Power RF teststand

klystron, focusing, PLC, FPGA

1138

A. Hamdi, M. Desmons, M. Luong, J. Novo
CEA/DSM/IRFU, France
F. Ballester
CEA, Gif-sur-Yvette, France

Supratech is a facility at CEA/Saclay that enables tests on superconducting and high power RF components for particle accelerators. The facility comprises a home-made hard tube HV modulator powering up to 95kV-20A at 2.1ms/50Hz and a 700MHz pulsed klystron developed by CPI able to produce RF up to 1MW-2ms/50Hz. A new compact HV and RF interlock system including klystron HV diagnostics has been implemented on Supratech test facility. This paper describes in more detail the klystron interlock system and the results of the first tests.

THP097

Use of Waveguide Probes as Beam position and Tilt Monitoring Diagnostics with Baseline and Alternative Superconducting Deflecting Cavities for the APS Upgrade

cavity, monitoring, dipole, HOM

1155

X. Sun, G. Decker, G. Wu
ANL, Argonne, USA

Funding: *Work supported by U.S. Department of Energy, Office of Science, under Contract No. DE-AC-02-06CH11357.
A set of superconducting deflecting cavities were studied for the APS Upgrade. A TM-mode baseline deflecting cavity design has been developed and prototyped, while an alternative design based on a TE-like mode is being studied. Waveguide field probes associated with the baseline and alternative superconducting deflecting cavities are explored as beam position and tilt monitoring diagnostics. Microwave Studio was used to simulate the technique of detecting the fields excited by a Gaussian bunch passing through the cavities to determine beam position relative to the electrical center. Probes installed on the horizontal midplane in the beam pipe are promising diagnostics for monitoring beam position and tilt in both designs. The probes in the power coupler also work as beam position monitors for the alternative deflecting cavities.