Sub 100 keV hard X-ray inverse compton sattering experiment at BNL ATF

Recent progress on the experiments of Inverse Compton Scattering (ICS) at Brookhaven National Laboratory Accelerator Test Facility (BNL ATF) is introduced. Nominal e-beam parameters utilized are electron beam energy of 70 MeV, charge per pulse of 0.5 nC with normalized emittance of 2 mm mrad. Use of long wavelength TW CO2 laser, and short wavelength Nd: YAG or Ti: Sapphire lasers allows us to explore unique nonlinear dynamics of Compton scattering such as Bi-Harmonic interaction and emission of Orbital Angular Momentum of X-ray. Currently, up to 90 keV hard X-ray yield from counter collision of Nd: YAG laser and 70 MeV electron beam is in a range of 1E6 photons per single pulse. Planning to increase electron beam energy to achieve establishment of sub 100 keV ICS to provide sufficient photon flux density, in the range of 1E10 per pulse, owing to the long wavelength multi TW CO2 laser and tighter electron beam focus is underway.