标题： 抛物线与椭圆聚焦 - 通过蒙特卡罗模拟优化冷三轴中子谱仪的聚焦设计 显示英文标题

标题： Parabolic versus elliptic focusing - Optimization of the focusing design of a cold triple-axis neutron spectrometer by Monte-Carlo simulations

摘要： 我们为一种新型冷中子三轴谱仪的聚焦设计进行了蒙特卡洛模拟，该谱仪将安装在德国慕尼黑研究反应堆FRM-II的冷导管NL-1的末端位置。 我们的模拟对于中子导管末端位置三轴谱仪的设计具有普遍的相关性。 使用McStas程序代码，我们进行了光线轨迹模拟，以比较抛物线和椭圆聚焦概念。 此外，单色器的设计也针对晶体尺寸和晶格畸变范围进行了优化。 从能量和发散度作为函数的中子强度分布来看，抛物线聚焦概念优于椭圆替代方案。 特别是，椭圆配置会导致发散度分布不均匀。 显示英文摘要

摘要： We present Monte-Carlo simulations for the focusing design of a novel cold-neutron triple-axis spectrometer to be installed at the end position of the cold guide NL-1 of the research reactor FRM-II in Munich, Germany. Our simulations are of general relevance for the design of triple-axis spectrometers at end positions of neutron guides. Using the McStas program code we performed ray trajectories to compare parabolic and elliptic focusing concepts. In addition the design of the monochromator was optimized concerning crystal size and mosaic spread. The parabolic focusing concept is superior to the elliptic alternative in view of the neutron intensity distribution as a function of energy and divergence. In particular, the elliptical configuration leads to an inhomogeneous divergence distribution.