Author: Lipka, D.
Paper Title Page
THPC111 Operation of an L-band RF Gun with Pulses Inside the Burst Mode RF Pulse 3146
 
  • V. Vogel, V. Ayvazyan, B. Faatz, K. Flöttmann, D. Lipka, P. Morozov, H. Schlarb, S. Schreiber
    DESY, Hamburg, Germany
 
  The Free-Elec­tron Laser in Ham­burg (FLASH) is a user fa­cil­i­ty since 2005, de­liv­er­ing fem­tosec­ond short ra­di­a­tion puls­es in the wave­length range be­tween 4.1 and 44 nm using the SASE prin­ci­ple. In FLASH, the elec­tron beam is ac­cel­er­at­ed to 1.25 GeV with L-band su­per­con­duct­ing cav­i­ties. The elec­tron source is a nor­mal con­duct­ing RF-gun pho­toin­jec­tor. The L-band stand­ing wave RF gun has one and a half cells. The gun is op­er­at­ed in burst mode with an RF pulse length of up to 900 mi­crosec­onds and a rep­e­ti­tion rate of 10 Hz. Sev­er­al hun­dreds to thou­sands of bunch­es are ac­cel­er­at­ed per sec­ond. With 5 MW of pulsed for­ward power, the dis­si­pat­ed power in­side the RF gun is 45 kW. In this paper we pro­pose an op­er­a­tional mode which al­lows us to re­duce the dis­si­pat­ed power to ease op­er­a­tion or to in­crease the ef­fec­tive duty cycle in the gun by puls­ing the gun with­in one burst. We re­port on first ex­per­i­men­tal re­sults at FLASH, where an RF burst of 46μRF-puls­es with a length of 10 mi­crosec­onds sep­a­rat­ed by 10 mi­crosec­onds has been suc­cess­ful­ly gen­er­at­ed re­duc­ing the dis­si­pat­ed power by a fac­tor of 2.