IPAC2013 - List of Authors (Zennaro, R.)

Paper	Title	Page
MOPFI062	Optimization Studies for the SwissFEL RF-Gun	425
	M. Schaer, A. Adelmann, A. Anghel, S. Bettoni, P. Craievich, L. Stingelin, C. Vicario, R. Zennaro PSI, Villigen PSI, Switzerland Z. Zhang TUB, Beijing, People's Republic of China
	The 250 MeV SwissFEL injector test facility is in operation since August 2010. Measurements with the "CTF2 Gun 5" photocathode S-band rf-gun show promising beam parameters and satisfy the requirements of the SwissFEL project. Since the performance of the electron source is fundamental for the stability and brightness of a free electron laser, further gun optimization studies are pursued. Under investigation is currently a 3.6 cell C-band gun. First ASTRA simulations indicate that with this gun the peak-current can be increased, thanks to a shorter laser pulse and a higher initial acceleration, by almost a factor of two, at slightly better emittance values than the S-band "PSI Gun 1". Since the beam-quality depends also on the achieved performance of the cathode, several copper cathodes had been tested in the SwissFEL injector test facility to analyze the observed rapid degradation of quantum efficiency.

WEPFI058	Breakdown Localization Studies on the SwissFEL C-band Test Structures	2824
	J. Klavins, S. Dementjevs, F. Le Pimpec, L. Stingelin, M. Wohlmuther, R. Zennaro PSI, Villigen PSI, Switzerland N.C. Shipman CERN, Geneva, Switzerland
	The SwissFEL main linac will consist of 10⁴ C-band structures with a nominal accelerating gradient of 28MV/m. First power tests were performed on short constant impedance test-structures composed of eleven double-rounded cups. In order to localize breakdowns, two or three acoustic emission sensors were installed on the test-structures. In order to localize breakdowns we have analyzed, in addition to acoustic measurements, the delay and phase of the rf power signals. Parasitic, acoustic noise emitted from the loads of the structure complicated the data interpretation and necessitated appropriate processing of the acoustic signals. The Goals of the experiments were to identify design and manufacturing errors of the structures. The results indicate that breakdowns occur mostly at the input power coupler, as also confirmed by vacuum-events at the same location. The experiments show that the linac test-structures fulfill the requirements in breakdown probability. Moreover developing a detection system based on acoustic emission sensors for breakdown localization for our C-band structure seems reasonable given the results obtained.

WEPFI059	C-band RF Pulse Compressor for SwissFEL	2827
	R. Zennaro, M. Bopp, A. Citterio, R. Reiser, T. Stapf PSI, Villigen PSI, Switzerland
	The SwissFEL C-band (5.712 GHz) linac consists of 28 RF modules. Each module is composed of a single 50 MW klystron feeding a pulse compressor and four two meter long accelerating structures. The pulse compressor is based on a single Barrel Open Cavity (BOC). The BOC makes use of a “whispering gallery” mode which has an intrinsically high quality factor and operates in resonant rotating wave regime; moreover, and contrary to the conventional SLED scheme, a single cavity is sufficient to define the pulse compressor, without the need for two cavities and a 3-dB hybrid. A prototype has been manufactured and successfully tested. A short description of the BOC is presented, together with the prototype design, production, low level RF measurements, and high power test.

Paper

Title

Page

Optimization Studies for the SwissFEL RF-Gun

425

M. Schaer, A. Adelmann, A. Anghel, S. Bettoni, P. Craievich, L. Stingelin, C. Vicario, R. Zennaro
PSI, Villigen PSI, Switzerland
Z. Zhang
TUB, Beijing, People's Republic of China

The 250 MeV SwissFEL injector test facility is in operation since August 2010. Measurements with the "CTF2 Gun 5" photocathode S-band rf-gun show promising beam parameters and satisfy the requirements of the SwissFEL project. Since the performance of the electron source is fundamental for the stability and brightness of a free electron laser, further gun optimization studies are pursued. Under investigation is currently a 3.6 cell C-band gun. First ASTRA simulations indicate that with this gun the peak-current can be increased, thanks to a shorter laser pulse and a higher initial acceleration, by almost a factor of two, at slightly better emittance values than the S-band "PSI Gun 1". Since the beam-quality depends also on the achieved performance of the cathode, several copper cathodes had been tested in the SwissFEL injector test facility to analyze the observed rapid degradation of quantum efficiency.

WEPFI058

Breakdown Localization Studies on the SwissFEL C-band Test Structures

2824

J. Klavins, S. Dementjevs, F. Le Pimpec, L. Stingelin, M. Wohlmuther, R. Zennaro
PSI, Villigen PSI, Switzerland
N.C. Shipman
CERN, Geneva, Switzerland

The SwissFEL main linac will consist of 10⁴ C-band structures with a nominal accelerating gradient of 28MV/m. First power tests were performed on short constant impedance test-structures composed of eleven double-rounded cups. In order to localize breakdowns, two or three acoustic emission sensors were installed on the test-structures. In order to localize breakdowns we have analyzed, in addition to acoustic measurements, the delay and phase of the rf power signals. Parasitic, acoustic noise emitted from the loads of the structure complicated the data interpretation and necessitated appropriate processing of the acoustic signals. The Goals of the experiments were to identify design and manufacturing errors of the structures. The results indicate that breakdowns occur mostly at the input power coupler, as also confirmed by vacuum-events at the same location. The experiments show that the linac test-structures fulfill the requirements in breakdown probability. Moreover developing a detection system based on acoustic emission sensors for breakdown localization for our C-band structure seems reasonable given the results obtained.

WEPFI059

C-band RF Pulse Compressor for SwissFEL

2827

R. Zennaro, M. Bopp, A. Citterio, R. Reiser, T. Stapf
PSI, Villigen PSI, Switzerland

The SwissFEL C-band (5.712 GHz) linac consists of 28 RF modules. Each module is composed of a single 50 MW klystron feeding a pulse compressor and four two meter long accelerating structures. The pulse compressor is based on a single Barrel Open Cavity (BOC). The BOC makes use of a “whispering gallery” mode which has an intrinsically high quality factor and operates in resonant rotating wave regime; moreover, and contrary to the conventional SLED scheme, a single cavity is sufficient to define the pulse compressor, without the need for two cavities and a 3-dB hybrid. A prototype has been manufactured and successfully tested. A short description of the BOC is presented, together with the prototype design, production, low level RF measurements, and high power test.