Zeng Guoqiang, Tan Chengjun, Ge Liangquan, Zhang Qingxian, Gu Yi
Chengdu University of Technology, Sichuan 610059, China.
Chengdu University of Technology, Sichuan 610059, China.
Appl Radiat Isot. 2014 Feb;85:70-6. doi: 10.1016/j.apradiso.2013.12.002. Epub 2013 Dec 16.
Abnormal multi-crystal spectral drifts often can be observed when power on the airborne gamma-ray spectrometer. Currently, these spectral drifts of each crystal are generally eliminated through manual adjustment, which is time-consuming and labor-ineffective. To realize this quick automatic spectrum stabilization of multi-crystal, a frequency spectrum analysis method for natural gamma-ray background spectrum is put forward in this paper to replace traditional spectrum stabilization method used characteristic peak. Based on the polynomial fitting of high harmonics in frequency spectrum and gamma-ray spectral drift, it calculates overall spectral drift of natural gamma-ray spectrum and adjusts the gain of spectrometer by this spectral drift value, thus completing quick spectrum stabilization in the power on stage of spectrometer. This method requires no manual intervention and can obtain the overall spectral drift value automatically under no time-domain pre-processing to the natural gamma-ray spectra. The spectral drift value calculated by this method has an absolute error less than five channels (1024 resolution) and a relative error smaller than 0.80%, which can satisfy the quick automatic spectrum stabilization requirement when power on the airborne gamma-ray spectrometer instead of manual operation.
在开启航空伽马能谱仪时，常常会观察到异常的多晶体光谱漂移。目前，各晶体的这些光谱漂移通常通过手动调整来消除，这既耗时又低效。为实现多晶体光谱的快速自动稳定，本文提出一种针对天然伽马射线本底谱的频谱分析方法，以取代传统的利用特征峰的光谱稳定方法。基于频谱中高次谐波与伽马射线光谱漂移的多项式拟合，计算天然伽马射线谱的整体光谱漂移，并根据该光谱漂移值调整能谱仪增益，从而在能谱仪开机阶段完成快速光谱稳定。该方法无需人工干预，在对天然伽马射线谱不进行时域预处理的情况下能自动获取整体光谱漂移值。用该方法计算出的光谱漂移值绝对误差小于5个道（1024分辨率），相对误差小于0.80%，可满足航空伽马能谱仪开机时快速自动光谱稳定的要求，无需人工操作。
