BESSY soft X-ray FEL

The BESSY soft X-ray FEL is planned as a linac-based single pass FEL multi user facility covering the VUV to soft X-ray spectral range (0.02 keV⩽ℏω⩽1 keV) [1,2]. A Photoinjector and a superconducting CW linac [3] will feed three independent SASE-FEL-lines consisting of APPLE II type undulators providing variable polarized radiation [2,4]. The performance of the SASE-FEL can be enhanced using a coherent seed which dominates the spontaneous emission at the beginning of the process. We present simulation studies for three BESSY-SASE-FELs as well as for possible multistage high-gain harmonic generation (HGHG) FELs and discuss their performance in terms of pulse power, pulse duration, pulse shape and signal-to-noise ratio.