用于凝聚态物质研究的旋转晶体中子飞行时间谱仪

本文介绍了我所自行设计和制造的一台旋转晶体中子飞行时间谱仪。该仪器对凝聚态物质的各种动力学研究是一个有效的工具。我们通过选取适当的锗单晶(111)平面旋转轴的办法消除了仪器单色束中多晶面反射的“污染”(contamination)。该谱仪的入射初始中子能量范围可为10—100meV,对应的初始中子能量分辨率为2.5—7.2％。本文根据Brockhouse理论对散射中子的分辨率作了详细的理论计算,并将计算结果与实测结果进行了对比。介绍了标准钒样品的非弹性散射中子谱的测量结果并与国外几个同类型谱仪的基本特性作了比较。

A ROTATING CRYSTAL NEUTRON TIME-OF-FLIGHT SPECTRO-METER FOR CONDENSED MATTER INVESTIGATION

A rotating single crystal thermal neutron time of flight spectrometer was constructed in IAB for the study of various dynamic process in condensed matter. The surplus reflections from undesired crystallographic planes in the rotating monochromator (Ge) is eliminated by carefully choosing a proper orientation of the rotating axis in the (Ⅲ) plane. The range of incident initial neutron energy is from 10 meV to 100 meV; The corresponding energy resolution is 2.5 to 7.2% with intensities adequate for inelastic scattering studies. Based on the work of Brockhouse et al., we have calculated a theoretical value of the resolution for neutrons scattered from the sample and compared it with measured results. Inelastic neutron scattering spectra from vanadium sample is presented and comparison with other spectrometers of similar type is given.