上海科技大学知识管理系统

Shanghai Laser Electron Gamma Source (SLEGS) is a powerful laser-Compton scattering (LCS) y-ray facility that provides a quasi-monochromatic MeV y-ray beam with a moderate flux of 105-107 photons/s. Accurate and fast measurement of the SLEGS y-beam flux is critical for the upcoming photonuclear experiments. In this study, an activation method based on 63 Cu(y, n)62Cu reaction is proposed for fast measurement of the SLEGS y-beam flux. By operating at a low beam flux of 104-105 photons/s, the SLEGS y-beam flux is measured within the energy range of 11.66-19.08 MeV. The y-beam flux as a function of laser power is also investigated. It was found that the flux data obtained by the proposed method is in reasonable agreement with the online monitoring of the LaBr3 detector and the GEANT4 simulations. The dependence of the total time (the sum of the irradiation time, the cooling time, and the detection time for identifying characteristic y-ray emission) on the y-beam flux is further studied. The total time could be controlled within 100 s when the beam flux exceeds 108 photons/s, suggesting the great potential of the 63 Cu activation method to quasi-real-time measure the LCS y-ray beam at high flux conditions.