SRF2013 - List of Authors (Carbonnier, P.)

Paper

Title

Page

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)

THIOD03

Cavity Development for the Linear IFMIF Prototype Accelerator

878

N. Bazin, P. Carbonnier, G. Devanz, G. Disset, N. Grouas, P. Hardy, F. Orsini, D. Roudier
CEA/DSM/IRFU, France
J. Neyret
CEA/IRFU, Gif-sur-Yvette, France

The Linear IFMIF Prototype Accelerator (LIPAc), which is presently under design and realization, aims to accelerate a 125 mA deuteron beam up to 9 MeV. Therefore, a low-beta 175 MHz Half-Wave Resonator (HWR) was initially designed and manufactured with a tuning system based on a capacitive plunger located in the electric field region. Following the results of the vertical tests at 4.2K, this tuning system was abandoned and replaced by a conservative solution based on the HWR wall deformation using an external mechanical tuner. This paper will focus on the manufacturing of the prototype cavity, the studies realized to explain the first test results and the solutions taken to overcome the difficulties, leading to the validation of the prototype. Then, we will present the new cavity design.

Slides THIOD03 [8.845 MB]

THP056

Validation Procedures for the IFMIF Power Coupler Prototypes

1043

H. Jenhani, P. Carbonnier, Y. Gasser, N. Grouas, P. Hardy, V.M. Hennion, F. Orsini, Y. Penichot, B. Renard, D. Roudier
CEA/IRFU, Gif-sur-Yvette, France
S.J. Einarson, T.A. Treado
CPI, Beverley, Massachusetts, USA
D. Regidor, M. Weber
CIEMAT, Madrid, Spain

In the framework of the International Fusion Materials Irradiation Facility (IFMIF), which consists of two high power CW accelerator drivers, each delivering a 125 mA deuteron beam at 40 MeV, a Linear IFMIF Prototype Accelerator (LIPAc) is presently under design for the first phase of the project. The first two IFMIF Power Coupler Prototypes were manufactured for LIPAc. Series of acceptance tests have been performed successfully. Prototype Power Couplers have been then cleaned and assembled in an ISO 5 cleanroom. A dedicated test bench allowing RF conditioning of the couplers up to 200 kW CW at 175 MHz was achieved. RF power conditioning is planned to start during October 2013.

Paper	Title	Page
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)

THIOD03	Cavity Development for the Linear IFMIF Prototype Accelerator	878
	N. Bazin, P. Carbonnier, G. Devanz, G. Disset, N. Grouas, P. Hardy, F. Orsini, D. Roudier CEA/DSM/IRFU, France J. Neyret CEA/IRFU, Gif-sur-Yvette, France
	The Linear IFMIF Prototype Accelerator (LIPAc), which is presently under design and realization, aims to accelerate a 125 mA deuteron beam up to 9 MeV. Therefore, a low-beta 175 MHz Half-Wave Resonator (HWR) was initially designed and manufactured with a tuning system based on a capacitive plunger located in the electric field region. Following the results of the vertical tests at 4.2K, this tuning system was abandoned and replaced by a conservative solution based on the HWR wall deformation using an external mechanical tuner. This paper will focus on the manufacturing of the prototype cavity, the studies realized to explain the first test results and the solutions taken to overcome the difficulties, leading to the validation of the prototype. Then, we will present the new cavity design.
	Slides THIOD03 [8.845 MB]

THP056	Validation Procedures for the IFMIF Power Coupler Prototypes	1043
	H. Jenhani, P. Carbonnier, Y. Gasser, N. Grouas, P. Hardy, V.M. Hennion, F. Orsini, Y. Penichot, B. Renard, D. Roudier CEA/IRFU, Gif-sur-Yvette, France S.J. Einarson, T.A. Treado CPI, Beverley, Massachusetts, USA D. Regidor, M. Weber CIEMAT, Madrid, Spain
	In the framework of the International Fusion Materials Irradiation Facility (IFMIF), which consists of two high power CW accelerator drivers, each delivering a 125 mA deuteron beam at 40 MeV, a Linear IFMIF Prototype Accelerator (LIPAc) is presently under design for the first phase of the project. The first two IFMIF Power Coupler Prototypes were manufactured for LIPAc. Series of acceptance tests have been performed successfully. Prototype Power Couplers have been then cleaned and assembled in an ISO 5 cleanroom. A dedicated test bench allowing RF conditioning of the couplers up to 200 kW CW at 175 MHz was achieved. RF power conditioning is planned to start during October 2013.