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LaBr3(Ce)-CsI(Tl)紧凑式叠层反康伽马探测器研制

Study on Compton-suppressed Phoswich Gamma-ray Detector of LaBr3(Ce)-CsI(Tl)

  • 摘要: 本工作研制了一套由圆柱形LaBr3(Ce)主晶体和井形CsI(Tl)次晶体组成的叠层伽马探测器,该探测器主要用于鉴别来自LaBr3(Ce)主晶体的康普顿散射光子并进行反符合测量。两种不同的晶体耦合到同一个光电倍增管上。入射辐射沉积在每一层探测器的能量,可以通过PMT给出的信号脉冲形状差异进行识别。利用Geant4模拟结果,验证了脉冲形状甄别性能和康普顿散射抑制效果。利用60Co伽马源对探测器进行了实验测试,测试结果表明,该探测器本底抑制系数为2.33(1),达到了康普顿本底抑制两倍以上的预期目标。

     

    Abstract: In this work, a compact phoswich detector consisting of a cylindrical LaBr3(Ce) principal crystal and a well-shaped CsI(Tl) sub-crystal was designed and assembled to identify and reject Compton scattering in the LaBr3(Ce). Two different crystals coupled to the same photomultiplier tube (PMT). The energy deposition in each layer from incident radiation is then determined via digital pulse shape analysis of the PMT’s pulses. The results of Geant4 simulations were used to verify the performance of the pulse shape identification and the effect of Compton background suppression. Experimental tests were conducted on the detector prototype using a 60Co gamma source, and the result shown that the detector background suppression coefficient was 2.33(1) which achieved the expected purpose of twice as much as the Compton background was suppressed.

     

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