惰性气体β-γ符合测量系统探测器能量及分辨率刻度

β-γ符合法是全面禁止核试验条约(CTBT)放射性核素核查中惰性气体氙测量的一种重要方法,探测器能量及分辨率刻度是其首要解决的关键技术。本工作详细介绍了β-γ符合测量系统NaI(Tl)闪烁体和塑料闪烁体探测器能量及分辨率刻度的方法和结果,采用γ放射性核素点源刻度NaI(Tl)γ射线能量及分辨率,利用137Cs661.66keVγ射线康普顿散射电子刻度塑料闪烁体β射线能量及分辨率,并与131Xem内转换电子刻度的β射线能量分辨率结果进行了比较。结果表明:用137Cs康普顿散射电子刻度塑料闪烁体β射线能量是一种简便可行的方法,但用其刻度的β射线分辨率比实际的大。

Energy and Resolution Calibration of Detectors for Noble Gas β-γ Coincidence System

The β -γ coincidence technique is a kind of important method to detect radio-active xenon isotopes for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The energy and resolution calibration of detectors is the first key technique. This paper describes in detail the energy and resolution calibration methods of NaI(Tl) and plastic scintillator detectors for the noble gas β-γ coincidence system SAUNAⅡ-Lab. NaI(Tl) detector’s energy and resolution for γ-ray were calibrated with γ radioactive point sources. Plastic scintillator detector’s energy and resolution for β-ray were calibrated by Compton scattering electrons of ¹³⁷Cs 661.66 keV γ-ray. And the results of β-ray energy resolution calibrated by Compton scattering electrons of ¹³⁷Cs were compared with the results of conversion electron of ¹³¹Xe^m. In conclusion, it is an easy and feasible method of calibrating plastic scintillator detector’s energy by Compton scattering electrons of ¹³⁷Cs, but detector’s resolution calibrated by Compton scattering electrons is higher than factual result.