航空伽马能谱探测系统探测关键技术研究

Airborne gamma spectroscopy prospect is a method to measure the radioactive emissions from the soil surface which results from the natural decay of isotopes in the soil.The information about the interface in airborne gamma spectroscopy imported from abroad is restricted. Under the conditions of unclear information, the factors can’t be accurately informed from airborne gamma spectroscopy system. That is why the precision accuracy about the instrument can’t improve..In this project there are five aspect which take as contributing factors to precision accuracy is summarized based on the Airborne gamma spectroscopy system which are self - developed with independent intellectual property rights. According the information from the instrument, the mechanism model is proposed and comes up with an answer. The interaction of multi-crystal gamma spectrometer is M-C simulated on the Geant4. According the nonlinear relationship between the energy Address, the adjust method is proposed. The digital technology is applied in the system to improve the energy resolution. The method combined the full spectrum matching and the peak area integration of digital PID is informed to release the high-precision Spectrum stabilization. The spectrum is de-noise by the NASVD to reduce the Statistical fluctuation on the low count rate. The technique is designed to automatically determine the drift of spectrum and correct. There technique will Improve the accuracy of the instrument. The resolution ratio extend from 256 channel to 1024 channel. The FWHM about the synthetic spectra cesium peak is within 8.5%.The measurement repeatability is better than 7%.This research will improve the accuracy of the instrument in the airborne gamma spectroscopy system to obtain the High quality data.

航空伽玛能谱勘探是获取地球放射性场的一种航空物探方法。受限于国外引进的航空能谱仪灵活性不够，接口数据开放有限，无法准确获知影响航空能谱勘探系统仪器探测精度的因素，也就无法提高仪器探测精度。本研究在课题组自主研制的航空伽玛能谱系统基础上，总结了影响仪器探测精度的五个因素，分别建立了机理模型，并提出解决方法。拟采用Geant4蒙特卡洛程序模拟了多晶体之间的相互影响建立能量非线性模型，提出能量非线性校正方法，采用数字能谱技术提高能量分辨率，使用全谱匹配结合峰面积积分的数字PID自动稳谱算法实现多晶体高精度稳谱，通过噪声奇异值调解法降低瞬时测量低计数率谱线窗口计数的统计涨落，设计离线的谱漂异常自动判断与校正方法。将航空伽玛能谱仪的分辨率由256道提高到1024道，确保合成谱铯峰的能量分辨率在8.5%以内，且测量重复精度优于7%。本课题研究将提高航空能谱系统的仪器探测精度，为后期的处理提供更多有用信

航空伽马能谱测量技术是铀矿资源勘查、辐射环境评价和核事故应急监测的重要手段，具有成果好、效率高、成本低等显著优势。本项目以组成航空伽马能谱探测系统中的探测器阵列为研究对象，展开了一系列的研究。在理论研究方面，开展了航空伽马能谱仪中阵列式探测器重相互影响的研究。通过建立对伽马射线在阵列探测器中的能量沉积分布模型，可以得到任意入射伽马入射阵列探测器后在相邻探测器中的能量沉积谱，进而实现对探测器能谱仪的修正；提出了采用墨西哥帽子小波与航空伽马能谱谱线进行卷积，达到扣除散射本底，获取能量特征峰的峰位和峰面积的方，并且对其稳定性进行了分析；提出了采用数据融合的方法对于航空伽马能谱数据进行处理的方法，并且采用Kalman数据融合的方法对模型站上的数据进行了处理。上述方法的应用为提升我国航空伽马能谱数据处理准确度和提升航空伽马能谱仪的探测提供了技术方法。