Highly integrated automated γ spectrometer

Abstract:

With respect to the need for online γ-ray monitoring in the containment of nuclear reactors, a γ spectrometer with high integration, low power consumption, high energy resolution, long endurance and automatic measurement is designed in this paper. A LaBr3(Ce) scintillator detector with high energy resolution is used in the spectrometer. And an active cone-shaped voltage divider circuit is designed to supply power to the detector and to improve the dynamic range of energy response of the spectrometer. Additionally, a low noise charge-sensitive preamplifier circuit is designed to amplify output signal of detector, and a second-order active low-pass filter circuit is designed to shape the front-end signal into a quasi-Gaussian pulse signal. A high integrated multi-channel pulse amplitude analysis circuit is designed by using STM32L4 series microprocessor to complete the analog-to-digital conversion and on-line data processing of the pulse signal and obtain γ energy Spectrum. In addition, we also designed a low-noise high-voltage power supply circuit based on the CC228P-09Y small high-voltage power supply module to provide high voltage for the LaBr3(Ce) detector. The power management circuit powered by lithium battery is designed by using STM32L4 series processor, thus the spectrometer can enter the working mode or standby mode automatically, realizing the automatic γ spectrum measurement function of long endurance time. In the end, a detailed performance test of the spectrometer is carried out: the energy resolution of the spectrometer is 3.0% (@ 662 keV), and the energy response integral nonlinearity is 9.5%. It can work stably for a long time and has the characteristics of low power consumption and long endurance time.