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前言中子散射研究,特别是中子小角散射、低激发态的中子非弹性散射以及具有高分辨的中子散射研究,需要长波长的中子(λ≥4(?))。目前原子能所重水堆上已开展的热中子散射工作基本上是在短波长区域,有必要扩充中子能量到长波长区域。为此,首先需要了解水平孔道漏出的长波中子谱形和一些低能中子单色器的反射特性,以便更好地确定相适应的长波长中子散射谱仪的类型。我们选择了“热解石墨单色器和Be过滤器”结构进行模拟,因为此种组合结构可以获得良好的低能单色中子,并且便利于使用国内产品和已有的设备。
Introduction Neutron scattering studies, especially neutron small-angle scattering, low-excited neutron inelastic scattering, and high-resolution neutron scattering require long wavelength neutrons (λ ≥ 4 (?)). At present, the work of thermal neutron scattering on the heavy water reactor of atomic energy is basically in the short wavelength region, so it is necessary to expand the neutron energy to the long wavelength region. To do this, we first need to understand the long-wave neutron spectra emerging from horizontal channels and the reflection characteristics of some low-energy neutron monochromators in order to better determine the type of long-wavelength neutron scattering spectrometer that is compatible. We chose the “pyrolytic graphite monochromator and Be filter” structure to simulate because this combination achieves good low-energy monochromatic neutrons and facilitates the use of domestic products and existing equipment.