Application of LaBr3 Detector in γ Production Cross Section Measurement
摘要
With the further development of various nuclear engineering projects and nuclear physics theories, the demand for higher-precision nuclear data has significantly increased. The γ-ray production cross section plays a crucial role in nuclear data and structure studies, and the γ branching ratios contribute to refining nuclear level schemes. The first white neutron source beamline in China has been established on the China Spallation Neutron Source, which can provide white neutrons ranging from 0.3 eV to 300 MeV. It is an ideal environment for conducting γ production cross section measurement experiment. However, the accompanying γ-flash causes severe signal pile-up or even saturation in slow time response γ detectors such as HPGe, and there is an urgent need to develop fast time response detectors for γ production cross section measurement experiments. As an emerging scintillation detector, LaBr3 detector has good time resolution and strong anti-signal pile-up performance. They are less affected by beam conditions when conducting online γ spectrum experiments. But they have the problems like complex background and lower resolution than HPGe detectors. By setting up a hybrid measurement array of LaBr3 detector and HPGe detector, the advantages can be combined to improve the measurement accuracy. The γ spectrum analysis method applicable to LaBr3 through a combination of experimental measurement and Monte Carlo simulation was studied. The form of the fitting function in the energy spectrum of the LaBr3 was analyzed, and the relationship between the peak shape parameter δ and step height parameter Astep in the fitting function with the variation of γ ray energy was studied. The analysis method of overlapping peaks in the energy spectrum was explored, and the fitting results were compared with offline calibration results to verify reliability. A hybrid array of LaBr3 detector and HPGe detector was set up on the HI-13 tandem accelerator at the China Institute of Atomic Ene