In this deliverable we report an overview of the possible injector options suitable to match the CompactLight X-band high brightness linac able to drive short wavelength FELs user facilities. Different schemes have been investigated including RF gun injectors at different operating frequency (S, C and X band) and a DC gun based design. The electromagnetic and RF designs for all cases are reported and discussed, including a preliminary evaluation of the laser/cathode system requirements. Matchings with the downstream linac are also investigated with beam dynamics simulations. State of the art S-band injectors look appropriate to achieve the required parameters at low repetition rate ( 100 Hz). On the other end a compact C-band (or X-band) RF gun design is expected to have even better performances at low repetition rates and moreover, due to the lower thermal load, could allow higher repetition rates operation, up to 1 kHz, with acceptable performances degradation. DC guns are also very promising solutions for kHz range operation.

On behalf of the CompactLight Collaboration