FEL2014 - List of Authors (Braun, H.-H.)

Paper

Title

Page

High Stability Resonant Kicker Development for the SwissFEL Switch Yard

103

M. Paraliev, H.-H. Braun, S. Dordevic, C.H. Gough
PSI, Villigen PSI, Switzerland

The SwissFEL is a linac-based X-ray free electron laser facility under construction at the Paul Scherrer Institute. The facility will provide femtosecond, high brightness X-ray pulses for fundamental and applied science research. To increase facility efficiency, a double bunch operation is planned to serve simultaneously two experimental stations at the full linac repetition rate. The main linac will accelerate two electron bunches spaced 28 ns apart and a fast and stable deflecting system will be used to separate the two bunches into two different undulator lines. The deflecting system uses a novel concept based on resonant kicker magnets. A prototype kicker magnet and its control system were designed and built. Since stability is crucial, the stability performance of the prototype was studied. The peak to peak amplitude stability of ±11 ppm (3.5 ppm rms) was achieved, which is well within the FEL tolerance of ±80 ppm. The layout of the deflecting system and the key design parameters are also presented.

TUA04

Status of the SwissFEL C-band Linac

322

F. Löhl, J. Alex, H. Blumer, M. Bopp, H.-H. Braun, A. Citterio, U. Ellenberger, H. Fitze, H. Jöhri, T. Kleeb, L. Paly, J.-Y. Raguin, L. Schulz, R. Zennaro, C. Zumbach
PSI, Villigen PSI, Switzerland

The linear accelerator of SwissFEL will be based on C- band technology. This paper summarizes the latest results that were achieved with the first prototype components. Fur- thermore, the progress and plans of the series production are discussed.

Slides TUA04 [11.482 MB]

WEB06

Introduction to the Paul Scherrer Institut Visit

H.-H. Braun
PSI, Villigen PSI, Switzerland

The Paul Scherrer Institute, PSI, is the largest research centre for natural and engineering sciences within Switzerland. The tour will consist in visiting three main sites of PSI: the Swiss Light Source (SLS), the SwissFEL Injector Test Facility (SITF) and the SwissFEL construction site. The latest being only a vista point on the on-going construction which is reached after a short walk through the forest. The lab visit will be followed by a Swiss evening at PSI where you will discover different cultural and culinary aspects of Switzerland.

Slides WEB06 [14.179 MB]

THP041

Development of All-metal Stacked-double Gate Field Emitter Array Cathodes for X-ray Free-electron Laser Applications

811

S. Tsujino, H.-H. Braun, P. Das Kanungo, V. Guzenko, C. Lee, Y. Oh, M. Paraliev
PSI, Villigen PSI, Switzerland
T. Feurer
Universität Bern, Institute of Applied Physics, Bern, Switzerland

Funding: This work was partially supported by the Swiss National Science Foundation Nos. 200020₁43428 and 2000021₁47101.
We report the design, fabrication, and characterization of all-metal stacked-double-gate field emitter array (FEA) cathodes as a potential upgrade option of SwissFEL cathode at the Paul Scherrer Institute. Single-gate FEAs have demonstrated stable operation and gated field emission in pulsed diode gun with gradient up to 30 MV/m with pulse duration down to 200 ps and generation of 5 pC electron bunches by near infrared laser-induced field emission. However for high brightness applications it is crucial to reduce the beam divergence of individual beamlet by a suitable double-gate structure. The challenge lies in suppressing the concomitant decrease of the emission current when a negative focusing potential is applied to the second gate. To solve this problem, a stacked-double-gate FEAs with large collimation gate aperture diameter has been proposed. The intrinsic transverse emittance evaluated from a beam measurement for 1 mm-diameter FEA was below 0.1 mm-mrad. Compatibility with neon-gas conditioning to improve the beam uniformity and high emission current with double-gate FEAs were also demonstrated recently. The current research is focusing on the combination of the surface-plasmon-polariton resonance of the gate electrode and the near infrared laser-induced field emission to realize an ultrafast and ultrabright FEA cathode.

THC02

Thermal Emittance Measurements at the SwissFEL Injector Test Facility

970

E. Prat, S. Bettoni, H.-H. Braun, M.C. Divall, R. Ganter, C.P. Hauri, T. Schietinger, A. Trisorio, C. Vicario
PSI, Villigen PSI, Switzerland
C.P. Hauri
EPFL, Lausanne, Switzerland

In a laser-driven RF-gun the ultimate limit of the beam emittance is the transverse momentum of the electrons as they exit the cathode, the so-called intrinsic or thermal emittance. In this contribution we present measurements of the thermal emittance at the SwissFEL Injector Test Facility for electron beam charges down to a few tens of fC. We have studied the thermal emittance and QE dependence on the laser wavelength, the RF-gun gradient and the cathode material (Cu and Cs2Te).

Slides THC02 [1.063 MB]

Paper	Title	Page
MOP039	High Stability Resonant Kicker Development for the SwissFEL Switch Yard	103
	M. Paraliev, H.-H. Braun, S. Dordevic, C.H. Gough PSI, Villigen PSI, Switzerland
	The SwissFEL is a linac-based X-ray free electron laser facility under construction at the Paul Scherrer Institute. The facility will provide femtosecond, high brightness X-ray pulses for fundamental and applied science research. To increase facility efficiency, a double bunch operation is planned to serve simultaneously two experimental stations at the full linac repetition rate. The main linac will accelerate two electron bunches spaced 28 ns apart and a fast and stable deflecting system will be used to separate the two bunches into two different undulator lines. The deflecting system uses a novel concept based on resonant kicker magnets. A prototype kicker magnet and its control system were designed and built. Since stability is crucial, the stability performance of the prototype was studied. The peak to peak amplitude stability of ±11 ppm (3.5 ppm rms) was achieved, which is well within the FEL tolerance of ±80 ppm. The layout of the deflecting system and the key design parameters are also presented.

TUA04	Status of the SwissFEL C-band Linac	322
	F. Löhl, J. Alex, H. Blumer, M. Bopp, H.-H. Braun, A. Citterio, U. Ellenberger, H. Fitze, H. Jöhri, T. Kleeb, L. Paly, J.-Y. Raguin, L. Schulz, R. Zennaro, C. Zumbach PSI, Villigen PSI, Switzerland
	The linear accelerator of SwissFEL will be based on C- band technology. This paper summarizes the latest results that were achieved with the first prototype components. Fur- thermore, the progress and plans of the series production are discussed.
	Slides TUA04 [11.482 MB]

WEB06	Introduction to the Paul Scherrer Institut Visit
	H.-H. Braun PSI, Villigen PSI, Switzerland
	The Paul Scherrer Institute, PSI, is the largest research centre for natural and engineering sciences within Switzerland. The tour will consist in visiting three main sites of PSI: the Swiss Light Source (SLS), the SwissFEL Injector Test Facility (SITF) and the SwissFEL construction site. The latest being only a vista point on the on-going construction which is reached after a short walk through the forest. The lab visit will be followed by a Swiss evening at PSI where you will discover different cultural and culinary aspects of Switzerland.
	Slides WEB06 [14.179 MB]

THP041	Development of All-metal Stacked-double Gate Field Emitter Array Cathodes for X-ray Free-electron Laser Applications	811
	S. Tsujino, H.-H. Braun, P. Das Kanungo, V. Guzenko, C. Lee, Y. Oh, M. Paraliev PSI, Villigen PSI, Switzerland T. Feurer Universität Bern, Institute of Applied Physics, Bern, Switzerland
	Funding: This work was partially supported by the Swiss National Science Foundation Nos. 200020₁43428 and 2000021₁47101. We report the design, fabrication, and characterization of all-metal stacked-double-gate field emitter array (FEA) cathodes as a potential upgrade option of SwissFEL cathode at the Paul Scherrer Institute. Single-gate FEAs have demonstrated stable operation and gated field emission in pulsed diode gun with gradient up to 30 MV/m with pulse duration down to 200 ps and generation of 5 pC electron bunches by near infrared laser-induced field emission. However for high brightness applications it is crucial to reduce the beam divergence of individual beamlet by a suitable double-gate structure. The challenge lies in suppressing the concomitant decrease of the emission current when a negative focusing potential is applied to the second gate. To solve this problem, a stacked-double-gate FEAs with large collimation gate aperture diameter has been proposed. The intrinsic transverse emittance evaluated from a beam measurement for 1 mm-diameter FEA was below 0.1 mm-mrad. Compatibility with neon-gas conditioning to improve the beam uniformity and high emission current with double-gate FEAs were also demonstrated recently. The current research is focusing on the combination of the surface-plasmon-polariton resonance of the gate electrode and the near infrared laser-induced field emission to realize an ultrafast and ultrabright FEA cathode.

THC02	Thermal Emittance Measurements at the SwissFEL Injector Test Facility	970
	E. Prat, S. Bettoni, H.-H. Braun, M.C. Divall, R. Ganter, C.P. Hauri, T. Schietinger, A. Trisorio, C. Vicario PSI, Villigen PSI, Switzerland C.P. Hauri EPFL, Lausanne, Switzerland
	In a laser-driven RF-gun the ultimate limit of the beam emittance is the transverse momentum of the electrons as they exit the cathode, the so-called intrinsic or thermal emittance. In this contribution we present measurements of the thermal emittance at the SwissFEL Injector Test Facility for electron beam charges down to a few tens of fC. We have studied the thermal emittance and QE dependence on the laser wavelength, the RF-gun gradient and the cathode material (Cu and Cs2Te).
	Slides THC02 [1.063 MB]