INITIAL EXPERIMENTAL RESULTS OF CAEP PHOTOINJECTOR

An RF photocathode gun which, along with a compact linac, forms the in jection system for a planned FIR FEL amplifier experiment, has been co mmissioned in the high power radiation laboratory. This high-gradient gun has emitted 60 ps, 10 A electron beams of up to 3 MeV energy. Thes e beams have been characterized by a variety of diagnostics. The quant um efficiency of Cs2Te has been measured at normal incidence. The ener gy and energy spread of the beam were tested using a dipole spectromet er, while the time structure was examined with a picosecond resolution streak camera. The emittance of the beam was measured using the peppe r pot technique and its dependence on space charge and RF phase were f ound. The impact of these results on improving the design and operatio n of this high brightness photoinjector is discussed. This injector wi ll be applied to the FIR FEL project in future. (C) 1998 Elsevier Scie nce B.V. All rights reserved.