• H. Leich, U. Gensch, M. Grimberg, L. Jachmann, W. Köhler, M. Penno, R.W. Wenndorff
  DESY Zeuthen, Zeuthen
• S. Choroba, H.-J. Eckoldt, T. Grevsmühl
  DESY, Hamburg

The European XFEL, an X-ray free electron laser, is planned as an European project with a strong connection to the DESY research center in Hamburg. Construction started in summer 2007 and commissioning will begin in 2014. The LINAC of the XFEL will incorporate 27 RF stations to supply the RF power required by the superconducting cavities. In order to generate this power (10MW at 1.3GHz) HV pulse modulators are required. Each modulator has to supply 12kV pulses at 1.6kA for 1.7ms pulse duration and at 10Hz nominal repetition rate. The repetition rate can be increased to 30Hz keeping the average power of the 10Hz operation. Although experience exists for FLASH with modulators constructed and built by one company two additional companies have been selected and contracted to design and to build additional prototypes of modulators according to the XFEL requirements. A test stand setup has been prepared at DESY, Zeuthen Site, in order to test and to operate these protoypes under similar conditions as at the XFEL. The presentation describes the Modulator Test Facility at DESY (Zeuthen Site) and presents and discusses test results of the modulator prototype from Thomson Multimedia.

• T. Grevsmühl, S. Choroba, F. Eints, T. Frölich, V.V. Katalev, K. Machau, P. Morozov, R. Wagner, V. Zhemanov
  DESY, Hamburg

The FLASH RF system consists of several RF stations, which provide RF power up to 10MW at 1.3GHz, 1.3ms and 10Hz repetition rate, each, for the superconducting cavities and the RF gun of the FLASH linear accelerator. During the last upgrade of the FLASH facility several modifications have been made also to the RF system. The oldest RF stations were constructed and manufactured by FNAL more than 15 years ago and have been replaced. Since one additional superconducting accelerator module has been added and one superconducting module and the RF gun have been replaced, modification and rearrangement of the RF waveguide distributions were required. An XFEL type waveguide distribution for the new accelerator module ACC7 and a distribution without individual phase shifters for the exchanged module ACC1 have been installed. A new waveguide distribution for the RF gun allows phase tuning by changing the gas pressure in the waveguides. It will also allow supply the RF gun by a 10MW multi beam klystron instead of the still used 5MW single beam klystron at a later point of time.