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在直径1.2米的回旋加速器上,建立了应用飞行时间方法的快中子能谱仪。利用回旋加速器的自然调制,获得了相位稳定而宽度不大于5—6毫微秒的脉冲中子源。中子探测器由有机晶体及作用快的光电倍加管组成,上升时间约为2—5毫微秒。测量中子飞行时间的单道时间分析器,是根据延迟符合的原理建立起来的。晶体二极管的并联符合线路,作为最简单的单道时间分析器,存在着下述缺点:它的分辨时间随输入脉冲幅度改变,在测量宽能量范围的中子时,会使中子能谱产生畸变。为了避免上述缺点并改善谱仪分辨能力,根据苏联符拉索夫等于1957年创造的差分单道时间分析器的设计原理,我们建成了一台快中子能谱仪。经过实验测试证明,性能达到苏联同类型谱仪的水平。
A fast neutron spectrometer using time of flight method was established on a cyclotron with a diameter of 1.2 m. Using a natural modulation of the cyclotron, a pulsed neutron source with phase stability of no more than 5-6 nanoseconds in width is obtained. The neutron detector consists of organic crystals and fast acting photomultiplier tubes, with a rise time of about 2-5 nanoseconds. A single-channel time analyzer that measures neutron flight time is based on the principle of delay compliance. As the simplest single-channel time analyzer, the parallel circuit of crystal diodes has the following shortcomings: its resolution time varies with the input pulse amplitude, and neutron spectra are generated when measuring neutrons in a wide energy range distortion. To avoid these shortcomings and to improve the resolving power of the spectrometer, a fast neutron spectrometer was built according to the design principle of the differential single-channel time analyzer created by the Soviet Union Labrador in 1957. After the experimental test proved that the performance of the Soviet Union to reach the same level of spectrometer.