用于提高康普顿相机探测效率的新型环状吸收体几何设计

A novel geometric design of annular absorber to improve detection efficiency of the Compton camera

    摘要
  • 摘要: 康普顿相机成像技术在许多领域都有重要应用．通过Geant4蒙特卡罗模拟和实验，本文提出了一种新型高灵敏度环状吸收体结构康普顿相机，并对比了该结构康普顿相机与传统双层面结构康普顿相机的探测效率和角度分辨率．模拟中，双层面结构康普顿相机散射体和吸收体均包含8×8的Ce:Gd3(Al, Ga)5O12 (GAGG)闪烁体探测器．散射体探测器单元尺寸为10 mm×10 mm×5 mm，吸收体探测单元尺寸为10 mm×10 mm×10 mm．新型环状吸收体结构康普顿相机散射体与双层面结构康普顿相机散射体相同，吸收体探测器单元分布在一个内半径51.5 mm、外半径约73.9 mm的环状结构上，总探测单元数与双层面结构康普顿相机吸收体探测器数相同，每个探测器单元尺寸为10 mm×10 mm×10 mm．模拟和实验结果显示，在角度分辨率相当甚至更优的情况下，新型环状吸收体结构康普顿相机的探测效率显著优于双层面结构康普顿相机，当散射体和吸收体距离>114 mm时，探测效率提高幅度超过1倍．

     

    Abstract: The Compton camera is widely used in various applications．A novel high-sensitivity Compton camera with an annular absorber was proposed here and its effectiveness was demonstrated via Geant4 simulation．The detection efficiency and angular resolution of this novel Compton camera were estimated and compared with a traditional Compton camera with two planar detectors．The scatterer of the two Compton cameras were identical and consisted of 8×8 Ce:Gd3(Al, Ga)5O12(GAGG) scintillator detector, each measuring 10 mm×10 mm×5 mm．The absorber of traditional camera contained 8×8 GAGG scintillator detector, each measuring 10 mm×10 mm×10 mm．The absorber of this novel camera contained 64 GAGG crystals (measuring 10 mm×10 mm×10 mm each), which were arranged in an annular shape with an inner radius of 51.5 mm and an outer radius of 73.9 mm．Simulation results show that with comparable or even better angular resolution, the novel Compton camera significantly enhanced effective detection efficiency．Data demonstrated that when distance between the scatterer and the absorber is larger than 114 mm, enhancement of detection efficiency is over 1-fold．

     

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