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The requirement of a short response time of a cathode with respect to the laser beam for the generation of the photoelectrons limits, in the case of SPARC photoinjectors, the choice of the cathode materials to metals that usually present response time on the order of a few tens of femtoseconds. While copper and magnesium have been extensively studied, new research activities were devoted to study the photoemission properties of yttrium and to explore the feasibility of a photocathode based on this metal. Nevertheless, to date little data has been reported in literature. We present, in this work, the results of our investigation of Y films as suitable materials for the production of bright electron beams. Bulk and thin films of Y, prepared by pulsed laser deposition on Si substrates, have been tested as photocathodes in an ultra-high vacuum photodiode chamber at 10-7 Pa. Systematic laser cleaning treatments improved the film quantum efficiency (QE) from 10-6 to 4.5×10-4 at 266 nm, comparable to those of the corresponding bulk. Preliminary QE measurements carried out in the visible range at 406 nm will be illustrated. [ABSTRACT FROM AUTHOR]

A 250-TW laser system (FLAME - Frascati laser for acceleration and multidisciplinary experiments) is now in its commissioning phase in a new laboratory at LNF-INFN in the framework of the PLASMONX (Plasma acceleration and monochromatic X-ray generation) project. The laser will deliver<25 fs duration pulses with an energy up to 6 J, at a 10 Hz repetition rate. An ad hoc target area has also been designed and is currently being set up, allowing the first test experiments of electron laser wakefield acceleration to be carried out over the next few months in a safe, radiation-protected environment. An overview of the main features of the laser system and target area is given, along with a survey of the design and set-up of the self-injection test experiment, which is expected to reach the production of sub-GeV electron bunches. [ABSTRACT FROM AUTHOR]