A New Design for Generation of Tunable Gamma-Ray With a Fixed Energy Electron Beam

A tunable quasi-monochromatic gamma-ray beam is indispensable not only for radiation measurements, but also for precise measurements of nuclear data. A design for generation of tunable quasi-monochromatic gamma-ray from the Compton backscattering of a laser light with a fixed energy electron beam has been investigated. We propose a new design (absorber- collimator scheme) by selecting the scattering angle of the Compton backscattered gamma-ray. Tunable gamma-ray can be obtained by changing the solid angle of the collimator (works as a low cut filter) and absorber (works as a high cut filter). A proof of principle experiment has been performed at the AIST-LCS beamline and the result showed that the absorber-collimator scheme could generate tunable gamma-rays. Numerical simulation based on the EGS4 well reproduced the experimental result.