Speaker
摘要
超快脉冲中子探测技术是诊断核反应时间演化过程特征的重要手段，在核裂变、聚变研究中发挥着不可替代的应用。然而，要对响应时间在纳秒量级的核反应过程准确诊断，就要求探测器必须具有纳秒量级的时间响应、超高的中子伽马分辨能力和合适的灵敏度。目前发展的以同轴法拉第筒和无源介质快中子探测器为代表的电荷收集型强流超快中子探测器，其灵敏度通常在10^(-25)~10^(-22) C∙cm^2之间，不能满足高灵敏度中子伽马辐射场探测与诊断的需要，因而必须发展能量收集型超快中子探测技术。在能量收集型探测器中，宽禁带半导体探测器最快能实现约1纳秒的脉冲响应，然而，其时间响应与探测器面积直接相关，同时它只能对信号进行一级放大，对于强度更低的辐射场，也存在困难和不足。为此，本研究计划探寻新型超快闪烁体，建立新的中子探测技术。通过协同攻关，中山大学生长的以量子限域效应调控缺陷发光而实现高光产额、快响应的氮化硼（BN）闪烁体为解决现有问题提供了可能。经过实验测量，该新型闪烁体对中子灵敏、对伽马不灵敏、时间响应在纳秒量级。将该新型闪烁体应用在薄膜探测器中，可以实现10^(-16) C∙cm^2的高灵敏度和纳秒量级的时间响应，有效填补了目前探测技术的空白。
Abstract
Ultrafast pulsed neutron detection is a critical diagnostic tool for characterizing the temporal evolution of nuclear reactions, playing an irreplaceable role in nuclear fission and fusion research. However, the accurate diagnosis of nuclear processes with nanosecond-scale reaction times requires detectors to possess nanosecond-level temporal resolution, exceptional neutron-gamma discrimination, and appropriate sensitivity.
Currently, charge-collection type high-intensity ultrafast neutron detectors—represented by coaxial Faraday cups and passive medium fast-neutron detectors—typically exhibit sensitivities in the range of 10^(-25)~10^(-22) C∙cm^2. These do not meet the requirements for high-sensitivity detection in neutron-gamma radiation fields, necessitating the development of energy-collection type ultrafast neutron detection technologies. Among these, wide-bandgap semiconductor detectors can achieve a pulse response of approximately 1 ns. However, their temporal response is directly coupled to the detector area. Furthermore, they are limited to primary signal amplification, posing significant challenges when diagnosing lower-intensity radiation fields.
To address these limitations, this research explores novel ultrafast scintillators to establish a new detdctor in neutron detection technology. Through collaborative innovation, Boron Nitride (BN) scintillators—developed by Sun Yat-sen University—leverage quantum confinement effects to regulate defect luminescence, achieving both high light yield and rapid response. Experimental measurements demonstrate that this novel scintillator is sensitive to neutrons while remaining insensitive to gamma radiation, with a temporal response on the nanosecond scale. By integrating this scintillator into thin-film detectors, a sensitivity of 10^(-16) C∙cm^2 and nanosecond-level time resolution can be achieved, effectively filling the current technological gap in high-sensitivity ultrafast neutron diagnostics.
| 关键词 | BN闪烁体；脉冲中子探测；灵敏度；响应时间 |
|---|---|
| Keywords | BN scintillator；Pulsed neutron detection；Sensitivity；Response time |
