垂直聚焦单色器的蒙特卡罗模拟计算

Simulation of Vertically Focused Monochromator by Monte-Carlo Method

利用蒙特卡罗方法对引进的1台粉未衍射仪上的垂直聚焦单色器进行模拟检验,以得到起实际作用的单色器尺寸、聚焦曲率半径和倾角等参数。计算和对比了使用聚焦单色器和平板单色器的强度增益和样品位置处的中子强度分布。结果表明：受孔道尺寸的限制,使用垂直聚焦单色器相对于使用平板单色器在样品尺寸较大的情况下无明显的强度增益,样品尺寸较小(10 mm×40 mm)时,使用垂直聚焦单色器能获得较显著的强度增益。

The vertically focused monochromator of the neutron powder diffractometer was simulated using Monte-Carlo method. The effective dimension, curvature radius and tilting angle of monochromator were obtained. The intensity gains comparing to flat monochromator and the neutron intensity distribution at sample position were also given. The result shows that there is not evident intensity gain for greater size sample because of the limit of hole dimension. Only for smaller size sample there is evident intensity gain.