Nondestructive detection and assay of nuclear material by laser compton gamma-rays from energy-recovery linacs

Nondestructive detection and assay of nuclear materials is one of the most urgent research issues for the management of nuclear waste as well as the non-proliferation of nuclear materials. We apply nuclear resonant fluorescence (NRF), which is a fingerprint of each isotope, to the nondestructive detection. Detection of NRF signals from objectives irradiated by quasi-monochromatic gamma-rays enables one to make quantitative assay of nuclear materials in a nondestructive manner. The quasi-monochromatic gamma-rays are available from Compton scattering of laser photons with relativistic electrons. In order to obtain high-flux gamma-rays for the above purpose, we propose to utilize an energy-recovery linac (ERL), which produces a high-brightness electron beam with high-average current. A design study of high-flux gamma-ray source based on an ERL shows that a gamma-ray flux of 1010 photons/sec/keV is obtained and detection of U-238 of 1 Bq/g in a concrete drum is possible within 1 second. In this paper, we present a design of the assay system and results of Monte Carlo simulations of NRF. (author)