FEL2014 - List of Authors (Paraliev, M.)

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.

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.

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.

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.