Feasibility study of ultra-short gamma ray pulse generation by laser Compton scattering in an electron storage ring

We are developing an ultra-short gamma ray pulse source based on laser Compton scattering technology. Ultra-short gamma ray pulses can be generated by injecting femtosecond laser pulses into the electron beam circulating in an electron storage ring from the direction perpendicular to the orbital plane. The energy, intensity, and pulse width of the gamma rays are estimated to be 6.6 MeV, 2.4×106 photons s−1, and 288 fs, respectively, for the case of a 750 MeV electron storage ring with a commercially available femtosecond laser. A preliminary head-on collision experiment was conducted. The measured spectral shape agreed well with the simulation, including the detector response calculated by the EGS5 code. The results implied that the generation of gamma rays occurred by laser Compton scattering and confirmed the validity of the estimation of the gamma ray intensity in the case of 90° collisions.