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本系统的任务是在较强γ场本底下,对较低的中子通量进行监测。和所有其他强本底下的放射性测量一样,如何抑制强本底的影响是个复杂的问题,解决的方法也较多。但在特殊的堆用环境下,用减少脉冲叠加的方法来减少本底计数,却是可能做到的。本系统就是用此方法,试制了KD-放大器而达到目的。以下仅就这一原理作简单说明。 用裂变室作为堆内探测元件时,探测器输出的信号主要有三种。一是中子脉冲,这是我们所期望的;二是γ脉冲;三是α脉冲,这是裂变室本身涂层的~(234)U、~(238)U等裂变的产物。这三者脉冲的大小,主要取决于在裂变室中引起气体电离的粒子的能量。α粒子平均能量为4MeV左右,γ粒子平均能量约为1MeV,而裂变碎片本身平均的能量为两个值:85MeV
The task of this system is to monitor the lower neutron flux under the strong gamma field. As with all other radioactivity measurements, how to restrain the impact of strong background is a complex issue and there are many solutions. However, it is possible to reduce the background count by reducing the pulse superposition in a special reactor environment. This system is using this method, trial-produced KD-amplifier to achieve the goal. The following is a brief description of this principle. Fissile chamber as a detection element within the heap, the detector output signal there are three main. The first is the neutron pulse, which is what we expect; the second is the γ pulse; the third is the α pulse, which is the fission product of ~ (234) U, ~ (238) U and other coatings in the fission chamber itself. The size of these three pulses depends mainly on the energy of the particles that cause gas ionization in the fission chamber. The average energy of the alpha particles is about 4 MeV, the average energy of the gamma particles is about 1 MeV, and the average energy of the fissile fragments itself is two values: 85 MeV