Free-electron laser operation with a superconducting radio-frequency photoinjector at ELBE

High Brightness Photo Injectors for Brilliant Light Sources

“…Several years of operation experience have been gained. Meanwhile the 3 1 2 cell SC RF gun is included in the ELBE accelerator and has provided first lasing of an IR FEL driven by an SC RF gun in April 2013 (Teichert et al 2013). The design parameters for operating the 3 1 2 cell SC gun at two different beam charges are given in column (d) and (e) of Table 2 (Arnold et al 2007;Teichert, private communication).…”

MicroTCA.4-Based Low-Level RF for Continuous Wave Mode Operation at the ELBE Accelerator

“…In order to avoid exciting these modes two notch filters are used. One is implemented in the MIMO controller and dedicated to the 7 9 π mode. Excitation of the 8 9 π mode is suppressed by the digital filter included in the dLLRF firmware.…”

“…The effective sampling rate in this I/Q detection scheme is 1.8 MHz. This approach reduces the controller bandwidth due to larger latency, but suppresses the 7 9 π passband mode which then cannot be excited. It allows the use of the MIMO notch filter to avoid exciting the 8 9 π passband mode and gains the freedom of having an extra spare digital filter available in the firmware.…”

“…Together, the bunchers achieve a longitudinal bunch compression factor of about 50. The second electron injector at ELBE [7] is based on SRF cavity technology similar to the technology used for the four SRF cavities used for the electron acceleration. The SRF injector is comprised of a 3.5 cell cavity.…”

Experimental studies of dark current in a superconducting rf photoinjector

“…In recent years, superconducting rf photoinjectors (SRF gun) have drawn a lot of attention because of their characters: continuous-wave (cw) operation, flexible bunch structures, low emittance compared to the other high average current sources [5] and the potential application for polarized beam generation [6]. The ELBE SRF gun within the cooperation of HZDR, HZB, DESY and MBI has been successfully commissioned [7,8] and firstly operated for the ELBE IR-FEL [9]. It is operated at a peak field E z: max of up to 16.2 MV=m at cw mode and 21.6 MV=m at macropulse mode.…”