Trigger Efficiency of a ZnS:6LiF Scintillation Neutron Detector Readout With a SiPM
Trigger Efficiency of a ZnS:6LiF Scintillation Neutron Detector Readout With a SiPM
复制标题
使用 SiPM 读出 ZnS:6LiF 闪烁中子探测器的触发效率
DOI：
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发表时间：
2016
影响因子：
1.8
通讯作者：
M. Hildebrandt
中科院分区：
文献类型：
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作者：
A. Stoykov;J. Mosset;M. Hildebrandt
探测中子吸收事件信号的效率使用装有中子吸收剂的ZnS吸收器的探测器的触发效率（6Li，10 B）的值容易被限制在远低于100%的值：闪烁体的非透明性导致探测信号的宽动态范围，其中某些部分总是落在设置为满足伽马灵敏度要求的探测阈值之下，多计数比和检测器的背景计数率。这种探测器的有限触发效率的问题很少在出版物中讨论，但它是非常重要的，因为触发效率和探测器中中子吸收概率的乘积定义了它的总效率。现有数据表明，用于中子衍射实验的基于PMT的探测器的触发效率可以低至~ 50%。在这项工作中，我们评估的触发效率的SiPM为基础的ZnS：6LiF闪烁中子探测器开发，以取代3 He探测器的POLDI飞行时间衍射仪在瑞士的Paul Scherrer研究所。在γ灵敏度≤10 ~（-7）、多计数比≤10 ~（-3）、探测器死时间为10 μs、本底计数率为10 ~（-3）Hz的条件下，我们得到了最大可能的触发效率~85%，主要限制来自γ灵敏度条件。考虑到在1°A下~80%的中子吸收概率，在该波长下的探测器效率达到~ 70%，这与POLDI仪器的当前3 He探测器的效率相当。
The efficiency of detecting signals from neutron absorption events (trigger efficiency) in detectors using ZnS scintillators loaded with neutron absorbers (6Li, 10B) is prone to be limited to values well below 100%: the non-transparency of the scintillator results in a wide dynamic range of the detected signals with some fraction always falling under the detection threshold set to satisfy the requirements on the gamma sensitivity, multi-count ratio, and the background count rate of the detector. The question of the limited trigger efficiency of such detectors is very seldom discussed in publications, yet it is very important as the product of the trigger efficiency and the probability of neutron absorption in the detector defines its overall efficiency. Available data indicate that the trigger efficiency of PMT-based detectors used in neutron diffraction experiments can be as low as ~ 50%. In this work we evaluate the trigger efficiency of a SiPM-based ZnS:6LiF scintillation neutron detector developed to replace a 3He-detector of the POLDI time-of-flight diffractometer at the Paul Scherrer Institut in Switzerland. Requiring the gamma sensitivity with a 60Co source ≤10-7, the multi-count ratio ≤10-3 with the detector dead time set to 10 μs, and the background count rate 10-3Hz we obtain the maximum possible trigger efficiency of ~85% with the main restriction coming from the gamma sensitivity condition. Considering the neutron absorption probability of ~80% at 1°Å, the detector efficiency at this wavelength amounts to ~ 70%, which is comparable to that of the current 3He-detector of the POLDI instrument.