Laser induced proton acceleration at the FLAME facility in Frascati: LILIA experiment

Abstract

A high power laser named FLAME with an intensity up to 1021 W/cm2, a repetition rate of 10 Hz and a contrast value (between main pulse and pre-pulse) of 1010 is being deployed at the LNF – INFN in Frascati and it is expected to be fully operative by the middle of 2012. In this frame an experiment of light ions ac-celeration through laser interaction with thin metal targets (LILIA) has been proposed and funded. The aim of LILIA experiment is to study, design and ver-ify a scheme which foresees the production, the char-acterization and the transport of a proton beam to-ward a stage of post acceleration (high frequency compact Linac). Now the maximum operating laser intensity is limited to 1019 W/cm2 due to the lack of a parabola with a focal length shorter that the current used. In this configuration, according to the interac-tion theory by short pulse laser and to performed nu-merical simulations, we expect a proton beam with maximum energy of a few MeV with a total dose up to 1010-1012 protons/shot. Although these values are modest compared to the present state of art, their sci-entific relevance is very important due to the fact that we will have a real laser driven source in the next year. In this paper we present the experimental set-up and the first tests of diagnostic devices based on radio-chromic films, Thomson parabola, solid-state diodes arrays and solenoid current detectors. A scheme for the focusing and the transport of an emitted proton beam based on a pulsed solenoid feed by a custom designed power supply will be also presented.