Photo-cathode analysis for SwissFEL

The SwissFEL facility is currently being built at Paul Scherrer Institut (PSI) and aims at the generation of sub-nanometer X-rays within a pulse duration in the order of 10 fs, by sending a high energy electron beam through undulators [1]. A key parameter to achieve this goal is the transverse brightness B_⊥ ∝ / I/ε_r² of the electron beam at the exit of the injector. A high peak current I and a low transverse emittance ε_r are required in order for the lasing process to work efficiently.