Amplification dans une cavité Fabry-Perot d'un laser à fibre picoseconde de très forte puissance moyenne. Application à la production de rayons gamma par interaction Compton. – MightLaser

The objective of the project is to reach the maximum laser pulse energy that can be stacked inside a very high finesse Fabry-Perot cavity and to implement the cavity in the electron accelerator ATF of the KEK Laboratory (Japan) in order to produce the highest gamma-ray beam flux ever achieved from laser-electron Compton scattering. ATF is an accumulation ring test facility built to test all the damping ring technologies which allow reaching extremely low emittances and to stabilize the extracted beam in the nanometric range. To reach our objective we propose to develop a pulsed high average power laser beam (more than 200W, 1 ps @ 178.5 MHz) and to lock it to a high gain (10000) optical resonator in order to store the MW average power level. This will allow a huge increase in the available pulse intensity in Compton collisions once the cavity and laser system will be installed at ATF/KEK. Depending on the energy of the impinging electron beam, the proposed technology will have a fundamental impact on both fundamental and applied research. In fact, Compton scattering is, by far, the physical effect that most efficiently boosts the photon energy (i.e. gamma rays production). In the past it has been exploited in very specific applications due to the extremely low value of its cross section. But, at present, the impressive increase in lasers and electron sources technologies allows to explore this domain for different possible applications in the field of fundamental and applied physics like the polarised positron sources for the future linear colliders and the applied medical, nuclear, material and biochemical sciences. The success of the project will open new areas of applications of X/gamma rays production with electron-laser Compton scattering.