分类： 物理学 >> 核物理学 提交时间： 2023-06-09 合作期刊: 《Nuclear Science and Techniques》
摘要： Real-time monitoring of the 14-MeV D-T fusion neutron yield is urgently required for the triton burnup study on the Experimental Advanced Superconducting Tokamak (EAST). In this study, we developed an optimal design of a fast-neutron detector based on the scintillating fiber (Sci-Fi) to provide D-T neutron yield through Geant4 simulation. The effect on the detection performance is concerned when changing the number of the Sci-Fis embedded in the probe head, minimum distance between the fibers, length of the fibers, or substrate material of the probe head. The maximum number of scintillation photons generated by the n/γ source particles and output by the light guide within an event (event: the entire simulation process for one source particle) was used to quantify the n/γ resolution of the detector as the main basis. And the intrinsic detection efficiency was used as another evaluation criterion. The results demonstrate that the optimal design scheme is to use a 5-cm probe head whose substrate material is pure aluminum, in which 463 Sci-Fis with the same length of 5 cm are embedded, and the minimum distance between the centers of the two fibers is 2 mm. The optimized detector exhibits clear directionality in the simulation, which is in line with the expectation and experimental data provided in the literature. This study presents the variation trends of the performance of the Sci-Fi detector when its main parameters change, which is beneficial for the targeted design and optimization of the Sci-Fi detector used in a specific radiation environment.
分类： 物理学 >> 核物理学 提交时间： 2023-09-13
摘要： Abstract: In this experimental study, involving deuteriumdeuterium fusion neutron emission spectroscopy (NES) measurement on the experimental advanced superconducting tokamak (EAST), a liquid scintillator detector (BC501A) was employed. This decision was based on the detector's superior sensitivity, optimal time-response, and its exceptional n- discrimination capability. This detector emits fast pulse signals that are as narrow as 100 ns, with high count rates that can peak at several Mcps. However, conventional nuclear circuits faced challenges in performing pulse height analysis, n pulse shape discrimination (PSD), and in recording the entire pulse waveform under such high-count-rate conditions. To address these challenges, a high-speed digital pulse signal acquisition and processing system was designed. The system was developed around a micro-telecommunications computing architecture (MTCA). Within this structure, a signal acquisition and processing (SAQP) module communicated through PCI Express (PCIe) links, achieving a bandwidth of up to 1.6 GB/s. To accurately capture the detailed shape of the pulses, four channels of analog-to-digital converters (ADCs) were used, each with a 500-MSPS sampling rate and a 14-bit resolution, ensuring an accuracy that surpassed 11 bits. An n- discrimination algorithm, based on the two-gate integral method, was also developed. Implemented within field programmable gate arrays (FPGA), this algorithm provided a real-time n- discrimination spectrum for pulse height analysis. The system underwent rigorous testing in a laboratory setting and during an EAST experiment. The results confirmed that the innovative SAQP system can satisfy the demanding requirements of high-parameter experiments, manage count rates of up to 2 Mcps, execute real-time n- discrimination algorithms, and record entire pulse waveforms without any data loss.
分类： 核科学技术 >> 核仪器、仪表 提交时间： 2023-06-01
Shi-Xing Liu
Wei Zhang
Zi-Han Zhang
Shuang Lin
Hong-Rui Cao
Cheng-Xin Song
Jin-Long Zhao
Guo-Qiang Zhong
摘要： 核安全防护通常需要同时探测中子和伽马射线，探测器的实时中子/伽马脉冲分辨是其关键性能参数。近年来，采用Cs2LiLaBr6 (CLLB)晶体的双读出探测器引起了广泛关注，论文研究电荷比较法、幅度比较法、时间比较法和脉冲梯度法的甄别性能，以及Sallen-Key滤波器的甄别效果。实验结果表明，通过合适的滤波，四种方法的品质因数(FOM)都有所提高。其中，电荷比较法抗噪声性能最佳，最适合CLLB探测器实时甄别中子/伽马脉冲。其甄别性能取决于参数、和。在对应脉冲峰值10%的时刻，，仅需延迟640-740 ns，此刻对应3.1-3.3 MeV的电荷比较方法最优FOM大于1.46。所提出的最大分辨差模型( MDDM)计算值与最优FOM的差异小于3.9%，表明该模型可以很好地指导电荷比较法的参数选择。
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