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arXiv 0805.0692nucl-exphysics.ins-det
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快中子和γ射线的数字脉冲形状鉴别

Digital pulse-shape discrimination of fast neutrons and gamma rays

P. -A. Söderström, J. Nyberg, R. Wolters

摘要:

本文用数字脉冲处理技术研究了液体闪烁体探测器探测快中子和γ射线的鉴别。使用具有252 Cf源、BC-501液体闪烁体探测器和BaF 2探测器的实验装置,以100 Ms/s、14位采样ADC收集波形。将三个相同的ADC组合以将采样频率提高到300 Ms/s。四种不同的数字脉冲形状分析算法的开发和相互比较,并获得与模拟中子伽马歧视单位的数据。其中两种数字算法基于电荷比较法,而模拟单元和另外两种数字算法基于零交叉法。两个不同的数字的优值参数,量化的中子-伽马歧视的属性,进行了评估,所有四个数字算法和模拟数据集。所有的数字算法给出了类似或更好的品质因数值比与模拟设置所获得的。作为采样频率和ADC的位分辨率的函数的歧视属性进行了详细的研究。结果表明,具有12位的位分辨率和100 Ms/s的采样频率的采样ADC足以实现具有0.3-12 MeV的沉积中子能量的动态范围的脉冲的最佳中子-伽马鉴别。研究了采样频率对时间分辨率的影响。在100 Ms/s时,半高宽为1.7 ns。

英文摘要:

Discrimination of the detection of fast neutrons and gamma rays in a liquid scintillator detector has been investigated using digital pulse-processing techniques. An experimental setup with a 252Cf source, a BC-501 liquid scintillator detector, and a BaF2 detector was used to collect waveforms with a 100 Ms/s, 14 bit sampling ADC. Three identical ADC's were combined to increase the sampling frequency to 300 Ms/s. Four different digital pulse-shape analysis algorithms were developed and compared to each other and to data obtained with an analogue neutron-gamma discrimination unit. Two of the digital algorithms were based on the charge comparison method, while the analogue unit and the other two digital algorithms were based on the zero-crossover method. Two different figure-of-merit parameters, which quantify the neutron-gamma discrimination properties, were evaluated for all four digital algorithms and for the analogue data set. All of the digital algorithms gave similar or better figure-of-merit values than what was obtained with the analogue setup. A detailed study of the discrimination properties as a function of sampling frequency and bit resolution of the ADC was performed. It was shown that a sampling ADC with a bit resolution of 12 bits and a sampling frequency of 100 Ms/s is adequate for achieving an optimal neutron-gamma discrimination for pulses having a dynamic range for deposited neutron energies of 0.3-12 MeV. An investigation of the influence of the sampling frequency on the time resolution was made. A FWHM of 1.7 ns was obtained at 100 Ms/s.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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