The construction of a high-repetition rate soft X-ray free electron laser
(FEL) with multi-user capability is being proposed at the Lawrence
Berkeley National Laboratory (LBNL). The extremely elevated brightness
of the FEL and its very short pulse length capability will optimally
complement the characteristics of the X-ray beam generated by the
Advanced Light Source, the storage ring-based source presently in
operation at LBNL. A fundamental requirement for operating this
new facility is the development of an electron source capable of
delivering electron bunches with the required quality at high repetition
rate. Such a source presently does not exist. In order to fill that gap,
a novel RF photo-injector has been conceived and is under
construction at LBNL. The scheme is based on a normal conducting
187 MHz RF cavity operating in continuous wave (CW) mode and
capable of generating an electron beam with charge, energy, energy
spread and transverse emittance suitable for FEL and energy recovery
linac applications. Additionally, a carefully designed vacuum system
will allow to run the photo-injector at the very low pressures required
by semiconductor photo-cathodes. The high quantum efficiency of
such cathodes will permit the generation of ~ nC electron bunches at
MHz repetition rate by using present laser technology. In the first part
of the talk, the LBNL FEL concept is presented, followed by a description
of the photo-injector and by an update on the status of its construction.

Transparencies

Fernando Sannibale.pdf (5.8 MB)

Fernando Sannibale.pdf