电容阳极光子计数探测器的机理与技术研究

Photon counting detector based on position sensitive anode has the advantages of low background noise and high quantum efficiency. Photon counting detector rebuilds the weak target imaging with high spatial resolution and high time resolution in a certain integration time, and is the essential device in fields like space ultraviolet imaging and astronomical observation. However the technology of photon counting detector in our country is terrible. The poor performance of photon counting detector has seriously hindered our further development of ionosphere detection in the near earth space and the deep ultraviolet observation. Therefore achieving major breakthrough and key technology innovation of theoretical research on the high performance position sensitive anode photon counting detector is urgent. Firstly, the physical mechanism of capacitive charge division and charge induction is systematically studied, and the theoretical model of charge induction is established. Secondly, experimental study on the photon counting detector based on capacitive anode is carried out. Self-designed germanium film and capacitive division anode are used to realize the key technologies such as capacitive charge induction and charge division among readout electrodes. Finally, the photon counting imaging is realized using the capacitive charge division readout and correlative signal processing algorithms. This project will provide a novel photon counting detector for research fields such as space ultraviolet spectroscopy, space particle science and X-ray pulsar navigation. Meanwhile it will promote the rapid development of these fields.

基于位敏阳极的光子计数探测器，具有背景噪声低、量子效率高的优点，能够在一定积分时间内重新建立极微弱辐射目标的像，且具有良好的空间分辨率和时间分辨率，是空间紫外探测的关键器件。然而我国光子计数成像研究领域技术落后，严重阻碍了我国近地空间电离层探测及深空紫外观测的深入发展，因而急需实现高性能位敏阳极光子计数探测器理论研究的重大突破与关键技术创新。本项目拟研究基于电容阳极的高空间分辨率、高计数率光子计数探测器的机理与技术。首先从理论上系统的研究电容分割电荷及电荷感应物理机制，并建立电容阳极电荷感应读出理论模型。其次，从实验上利用自行设计的电容阳极板实现电容阳极电荷感应及电荷分割等关键技术，并最终实现电容阳极光子计数成像。本项目研究将为我国空间紫外光谱成像、空间粒子科学、X射线脉冲星导航等应用研究领域提供新型光子计数探测器，并促进这些领域的快速发展，研究意义重大。

基于位敏阳极的光子计数探测器，具有背景噪声低、量子效率高的优点，能够在一定积分时间内重新建立极微弱辐射目标的像，被广泛的用于深空紫外、极紫外、X射线以及各种高能带电粒子的探测。然而我国光子计数成像研究领域技术落后，严重阻碍了我国近地空间电离层探测及深空紫外观测的深入发展，因而急需实现高性能位敏阳极光子计数探测器理论研究的重大突破与关键技术创新。为打破国内位敏阳极紫外成像技术落后局面，突破我国未来空间天文发展的先进紫外辐射探测器技术，从而保证空间天文的可持续性发展以及未来全波段空间天文发展的需要。本项目系统开展了基于电容阳极的高空间分辨率、高计数率光子计数探测器的机理与技术研究。一方面，完善了电容阳极光子计数探测器的物理模型，为电容阳极光子计数探测器设计提供理论依据。另一方面，发展了一种PCB过孔阵列电容阳极设计方案，构建了过孔阵列板电容阳极电磁仿真理论模型，并在此基础上采用单元电容渐变补偿方案设计出一种新的电容阳极。最总，通过过孔阵列线性排布电容阳极及渐变补偿电容阳极理论及实验对比研究，优化了电容阳极理论模型，实验获得空间分辨率达到45µm，计数率达1MHz的光子计数成像结果。电容阳极作为一种新型单光子探测器，随着相关理论研究的不断深入，以及设计方案的不断优化，其性能将不断得到提升，应用前景将逐渐明朗，特别是本项目采用的渐变补偿电容阳极可获得中心区域的高空间分辨，这在生物、医学等微区光子计数成像领域有巨大应用前景。