核脉冲信号数字成形算法与实时处理技术的研究

The signal acquired by nuclear detectors is random pulse. And there are many factors such as pulse pile-up, baseline drift and noise signal which have restricted the stability, reliability and accuracy of nuclear insturments seriously. Therefore digitization is the main direction of modern nuclear instruments system. The main characteristics between the digital spectrometer system and analog system are digital pulse shaping and pulse amplitude extraction. Nowadays, there are numerous research achievements about high speed data acquistion and main amplifying circuit. However, there are also many decisive techniques which must be improved urgently such as theories and algorithms of digital shaping, design of shaping time and matching with the nuclear detectors. Especially, the nuclear pulse signal shaping methods are still limited to theoretical calculation and experimental simulation. And there has no research reports of the algorithms based on hardware system in real-time. Aiming at the urgent demand of nuclear instrument digitalization, there are three mainly contents in the project. Firstly, the hardware platform of high speed nuclear signal data acquisition system should be constructed. Secondly, the software platform will also be established basing on the VBA techniques. And so on, the theory algorithms of digital pulse signal shaping such as Gauss, trapezoidal and triangle will be studied deeply. Lastly, through repeated tests and verifications on the hardware software platform, the algorithms of digital shaping will be improved progressively. And finally, the practical ones basing on FPGA hardware system will also be implemented.

核探测器获取的信号为随机脉冲信号，脉冲堆积、基线漂移、噪声信号等干扰因素严重制约了核仪器的可靠性、稳定性和精确性。因此，数字化成为了核仪器的重要发展方向，数字滤波成形、脉冲幅度提取等数字能谱核心技术是区别模拟能谱的主要方面。其中，在主放电路、高速核信号采集等研究成果较为丰硕，但数字成形理论及算法构建、成形时间设计及探测器匹配等关键技术亟待完善。特别是核脉冲信号数字成形算法仍局限于理论计算与实验仿真，基于硬件系统实时处理的算法几乎没有报道。针对核仪器数字化研究的迫切需求，拟开展的研究为：⑴构建研究所需的硬件平台，实现高速核脉冲信号的实时采集；⑵构建基于VBA技术的核脉冲信号数字成形理论算法的软件测试平台，进而深入研究高斯成形、梯形成形和三角形等数字成形理论算法；⑶利用所构建的硬件平台和软件平台反复测试数字成形理论算法，最终研发可在FPGA硬件平台上加以实现的实时核脉冲信号数字成形的实用算法。

自1896年天然放射性被发现以来，核辐射探测在国民经济中工业、农业、服务业等众多部门得到广泛地应用。其中，探测射线并确定其性质一直是核物理研究和核技术研究的中心环节，而探测射线的关键是探测器和测量系统。目前，世界上有近100个国家开展了核技术有关的研究、开发和利用。经过一百多年的发展，核技术产业取得了日益明显的经济效益。国内核技术的发展首先开始于上世纪50年代中期的国防军工领域，而后核技术研究逐渐渗透到科学研究、医学、农业、工业等各个领域。然而总体而言，我国核技术的发展尚处在初级阶段，在分析方法和技术手段上与发达国家差距明显。详细分析各国核技术产业产值的组成，在非核能领域内我国核技术产业产值所占比重与发达国家相比，差距更加明显。由此可见，中国核技术产业有着很大的市场和很好的发展前景。.核探测器获取的信号为随机脉冲信号，脉冲堆积、基线漂移、噪声信号等干扰因素严重制约了核仪器的可靠性、稳定性和精确性。因此，数字化成为了核仪器的重要发展方向，数字滤波成形、脉冲幅度提取等数字能谱核心技术是区别模拟能谱的主要方面。其中，在主放电路、高速核信号采集等研究成果较为丰硕，但数字成形理论及算法构建、成形时间设计及探测器匹配等关键技术亟待完善。特别是核脉冲信号数字成形算法仍局限于理论计算与实验仿真，基于硬件系统实时处理的算法几乎没有报道。针对核仪器数字化研究的迫切需求，拟开展的研究为：⑴构建研究所需的硬件平台，实现高速核脉冲信号的实时采集；⑵构建基于VBA技术的核脉冲信号数字成形理论算法的软件测试平台，进而深入研究高斯成形、梯形成形和三角形等数字成形理论算法；⑶利用所构建的硬件平台和软件平台反复测试数字成形理论算法，最终研发可在FPGA硬件平台上加以实现的实时核脉冲信号数字成形的实用算法。.综上所述，数字化已成为核仪器仪表发展的必然方向，深入研究核脉冲信号数字成形的理论算法及其相应的实时处理技术是势在必行的。