The Two CTF3 Photoinjectors

by Massimo Petrarca

Wednesday 22 Apr 2009, 16:00 → 17:00 Europe/Zurich

30-7-018 (CERN)

CTF3 is a CERN facility built and operated by an international Collaboration, that aims at demonstrating the feasibility of the main critical issues regarding the CLIC concept i.e. two beams acceleration, high gradient and high frequency accelerating structures, stability of high charge high current electron beams etc. The CLIC and CTF3 demand for short electron bunches (few picoseconds) makes of laser driven photoinjectors the natural choice for the source. The flexibility required to temporally shift the micro-bunch structure contained in a time window of 140 ns (macro-bunch) puts even more constraints on the choice of this type of source. This latest feature, called "phase coding", is necessary for the multiplication in frequency of the drive beam in the CTF3 delay loop and combiner ring. Two photoinjectors have been built in the last years: the drive beam PHIN photoinjector, named by the FP6 EU program that provided most of the funds to build it in a collaboration between CERN, RAL, LAL, INFN Frascati and INFN Milano. The CALIFES photoinjector, which provides the seed to the so-called probe beam accelerator, was built in collaboration between CEA/DAPNIA, CERN and LAL. Two preliminary tests have been performed on the photoinjectors at the end of 2008. In 2009 the two machines are undergoing further test for a more detailed study. In this seminar a brief description of the CTF3 facility will be presented and some information will be provided about the design of the photoinjectors and their main constituents i.e. laser, RF gun and photocathodes. Some encouraging preliminary results from the recent beam tests will be shown.

Paper EN_Seminar_Petrarca_long_90422[1]

Slides Petrarca_dep_seminar_FINAL.pdf