Based on user-driven scientific requirements, the CompactLight collaboration has determined the ideal wavelength range, beam structure, pulse duration, synchronisation to external laser, pulse energy, polarisation, etc., that should be achieved by an X-band-driven hard X-ray FEL. The resulting design includes also options for soft X-ray operation, external seeding schemes to produce longitudinally coherent x-ray pulses, and double pulse operation for FEL-pump FEL-probe experiments. The figure below shows the peak photon brightness targeted by CompactLight in the framework of the present short-wavelength FEL facilities.
The user requirements for CompactLight have been established by interacting with existing and potential FEL users in a variety of formats. We have distilled all of these inputs into a comprehensive photon output specifications, summarised in the following table: