基于波形高速获取与处理的数字化探测器技术研究

Energy,type,position and time of a particle may exist in a signal from nuclear detector bombarded by the particle. Traditional complicated nulear electronics may get just one information from the signal. More information may be gotten with a simplified system which is made of traditional detectors combined with digital acquisition and process system of signal shape.This is a new developing direction for nuclear detection and measurement.In this project, integration technology of NaI(Tl),LaBr3(Ce),plastic scintillator detectors coupled with digital acquisition and process of signal shape will be studied, the prototype of inteligent detectors mentioned above will be produced,the algorithms for digital instrument of nuclear detector (shuch as filtering, algorithm for intrinsic parameters, pile-up identification and spectrum analysis,base line shift and restore, discrimination of pulse shape,timing and time measurement from discrete series of signal,and so on) will be studied and developed, a desktop of software development for digital nuclear detectors will be designed and developed, the methods for testing the parametors of nuclear detectors will be studied. a typical sample of digital nuclear detectors based on digital acquisition and process of signal shape will be constructed. The research results of the project may lead to change of traditional nuclear electronics, will be very important to both science and application.

辐射探测器输出信号可能同时包含粒子能量、种类、位置、时间等信息，如果对信号波形进行数值化获取，配合相应的处理算法，不仅可以获得更多的信息，而且相同的探测器可以根据算法的不同具有不同的功能，明显优于传统的核电子学方法，这是辐射探测技术的发展方向。本项目基于脉冲波形高速获取与处理技术，针对NaI(Tl)，LaBr3(Ce)，塑料闪烁体等三种类型探测器，研究信号波形高速获取与处理技术及其与探测器的集成技术，研究并获得数字化探测器核心算法，如各种滤波算法、辐射特征量提取方法、堆积判别与解谱方法、基线漂移估计与恢复方法、脉冲形状甄别算法、基于离散序列的定时方法与时间测量算法、数字化符合测量方法等，实现三种类型数字化探测器原型样机，研究数字化探测器性能指标测试方法，构建基于波形获取与处理的数字化探测器应用范例。该研究是对传统的辐射探测和核电子学方法的变革，既有重要的科学意义，更有广泛的应用前景。

本项目基于波形高速采样和数字化处理技术，提出了多种类型探测器一体化集成技术方案，研制成功了NaI(Tl)、LaBr3(Ce)和塑料闪烁体数字化谱仪样机，研制成功了基于NaI(Tl)和塑料闪烁体的n-γ混合辐射场测量仪，研制成功了基于LaBr3(Ce),PIPS探测器的α，β，γ联合测量谱仪。基于FPGA，研究并实现了多种实时在线数字波形处理算法，包括滤波算法、基线提取、脉冲幅度提取算法和恒比定时算法等。以塑料闪烁体谱仪为对象进行了n-γ波形甄别算法研究，确定了电荷比较法的最佳参数。针对n-γ混合辐射场的测量，提出了双探测器一体化联合测量方法。进行了能谱反解算法研究，获得了γ能谱和中子能谱反解算法，提高了混合辐射场中子谱和剂量测量的准确性。使用多种γ源、同位素中子源和加速器中子源对谱仪样机进行了多方面测试，NaI(Tl)谱仪样机的能量分辨率和LaBr3(Ce)谱仪样机的能量分辨率均优于传统谱仪。利用NaI(Tl)和塑料闪烁体谱仪对中子和γ混合场进行测量，得到了与实验符合较好的中子入射谱。该项目研究成果已经用于与相关军工企业的合作开发。本项目成果为便携式小型化核辐射检测仪和仪器仪表开发奠定了理论和技术基础，在核应急状态下的快速辐射检测，放射性核素识别，核安检，军用核装备研制开发等，有重要应用前景。