A gamma and neutron phoswich read out with SiPM for SPRD
A gamma and neutron phoswich read out with SiPM for SPRD
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DOI：
10.1016/j.nima.2017.11.007
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发表时间：
2018-02
影响因子：
1.4
通讯作者：
Tuchen Huang;Qibin Fu;C. Yuan;Shaopeng Lin
中科院分区：
文献类型：
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作者：
Tuchen Huang;Qibin Fu;C. Yuan;Shaopeng Lin
研制了一种用于光谱个人辐射探测器的γ-中子磷开关。它由Φ 25× 25 mm的NaI（Tl）γ探测晶体和Φ 25× 3 mm的LiI（Eu）中子探测晶体组成。用8× 8通道SiPM阵列（24× 24 mm 2）读出。NaI（Tl）和LiI（Eu）中的辐射由脉冲形状区分，而LiI（Eu）中的γ和中子由脉冲幅度区分。对于LiI（Eu），热中子的伽马等效能量测量为3.6±0.1 MeV，提供了令人满意的伽马抑制。对于NaI（Tl），SiPM阵列的响应在1408 keV能量范围内具有良好的线性，测量偏差小于2%.数字脉冲形状鉴别（PSD）是用一个8位数字转换器运行在50 MSPS的采样率和离线分析。来自NaI（Tl）和LiI（Eu）的信号脉冲在允许有效PSD的下降沿中显示出显著差异。最佳品质因数（FOM）在优化参数下测得为4.4±0.2，提供了优异的PSD性能。在选定的PSD阈值下，对661.6keV γ射线NaI（Tl）和热中子LiI（Eu）的能量分辨率分别为7.0±0.2%和11.2±0.2%。
A gamma and neutron phoswich was developed for spectroscopic personal radiation detectors (SPRDs). It consisted of a Φ 25× 25 mm NaI (Tl) crystal for gamma detection and a Φ 25× 3 mm LiI (Eu) crystal for neutron detection. The phoswich was read out by 8× 8 ch SiPM array (24× 24 mm 2). Radiations in NaI (Tl) and LiI (Eu) were discriminated by pulse shape, while gammas and neutrons in LiI (Eu) were separated by pulse amplitude. For the LiI (Eu), the gamma equivalent energy for thermal neutrons was measured as 3.6±0.1 MeV, providing satisfactory gamma rejection. For NaI (Tl), the response of SiPM array was well linear in the energy range up to 1408 keV, at which a deviation less than 2% was measured. Digital pulse shape discrimination (PSD) was implemented with an 8-bit digitizer running at 50 MSPS sampling rate and offline analysis. The signal pulses from NaI (Tl) and LiI (Eu) showed significant difference in falling edge allowing effective PSD. The best figure of merit (FOM) was measured as 4.4±0.2 with optimized parameters, providing excellent PSD performance. The energy resolutions for 661.6 keV gamma rays in NaI (Tl) and thermal neutrons in LiI (Eu) were measured as 7.0±0.2% and 11.2±0.2% respectively, with selected PSD threshold.