SRF2013 - List of Authors (Ballester, F.)

Paper	Title	Page
THP090	Compact Interlock System for Supratech High Power RF teststand	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.

TUP046	Vertical Electropolishing of SRF Cavities and its Parameters Investigation	514
	F. Eozénou, F. Ballester, Y. Boudigou, P. Carbonnier, J.-P. Charrier, Y. Gasser, D. Roudier, C. Servouin CEA/DSM/IRFU, France K. Muller Grenoble-INP Phelma, Grenoble, France
	Funding: We acknowledge the support of the European Community-Research Infrastructure Activity under the FP7 program (EuCARD, Contract No. 227579),and the support of the ‘‘Conseil General de l’Essonne’’(ASTRE) An advanced set-up for vertical electropolishing (VEP) of SRF niobium elliptical cavities is operating at CEA Saclay. Cavities are VEP’ed with circulating standard HF-H2SO4 electrolyte. Parameters such as voltage, cathode shape, acid flow and temperature were investigated. Low-voltage (<7V), high acid flow (25L/min) and low acid temperature (20°C) are considered as promising parameters. Such recipe was tested on single-cell and 9-cell ILC cavities with nice surface finishing. After 60 μm VEP on a HEP'ed single-cell, the cavity show similar performance at 1.6K compared to previous Horizontal EP: (Eacc > 41MV/m) limited by quench. Another cavity reaches 36MV/m after 300μm removal by VEP in spite of a pitted surface due to initial VEP treatment at higher temperature (> 30°C). The baking effect after HEP/VEP is similar. An asymmetric niobium removal is observed with faster polishing in the upper cell. Nice surface finishing as well as standard Q0 value are obtained at low/medium field on 9Cell but achieved performance is limited by Field Emission. F. Eozenou et al., PRST-AB, 15, 083501 (2012)

Paper

Title

Page

Compact Interlock System for Supratech High Power RF teststand

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.

TUP046

Vertical Electropolishing of SRF Cavities and its Parameters Investigation

514

F. Eozénou, F. Ballester, Y. Boudigou, P. Carbonnier, J.-P. Charrier, Y. Gasser, D. Roudier, C. Servouin
CEA/DSM/IRFU, France
K. Muller
Grenoble-INP Phelma, Grenoble, France

Funding: We acknowledge the support of the European Community-Research Infrastructure Activity under the FP7 program (EuCARD, Contract No. 227579),and the support of the ‘‘Conseil General de l’Essonne’’(ASTRE)
An advanced set-up for vertical electropolishing (VEP) of SRF niobium elliptical cavities is operating at CEA Saclay*. Cavities are VEP’ed with circulating standard HF-H2SO4 electrolyte. Parameters such as voltage, cathode shape, acid flow and temperature were investigated. Low-voltage (<7V), high acid flow (25L/min) and low acid temperature (20°C) are considered as promising parameters. Such recipe was tested on single-cell and 9-cell ILC cavities with nice surface finishing. After 60 μm VEP on a HEP'ed single-cell, the cavity show similar performance at 1.6K compared to previous Horizontal EP: (Eacc > 41MV/m) limited by quench. Another cavity reaches 36MV/m after 300μm removal by VEP in spite of a pitted surface due to initial VEP treatment at higher temperature (> 30°C). The baking effect after HEP/VEP is similar. An asymmetric niobium removal is observed with faster polishing in the upper cell. Nice surface finishing as well as standard Q0 value are obtained at low/medium field on 9Cell but achieved performance is limited by Field Emission.
*F. Eozenou et al., PRST-AB, 15, 083501 (2012)