Performance Comparisons of Four Direct Geometry Spectrometers Planned for the Spallation Neutron Source
Performance Comparisons of Four Direct Geometry Spectrometers Planned for the Spallation Neutron Source
复制标题
散裂中子源计划的四种直接几何能谱仪的性能比较
DOI：
--
复制
发表时间：
2008
期刊：
影响因子：
--
通讯作者：
D. Abernathy
中科院分区：
文献类型：
--
作者：
G. Granroth;D. Abernathy
四个直接几何光谱仪计划用于SNS。CNCS是一种使用冷中子的多斩波器仪器。HYSPEC谱仪使用圆盘斩波器和垂直聚焦单色器来选择冷中子和热中子。ARCS谱仪是一种费米斩波器仪器，具有大角度覆盖范围，使用热中子到超热中子。SEQUOIA光谱仪是一种费米斩波器仪器，具有较长的最终飞行路径，使用热中子到超热中子。为了比较这四种仪器的性能，使用McStas Monte Carlo软件包对每种仪器进行了模拟。在不同入射能量（Ei）和能量分辨率（ε ω）条件下比较了样品上通量的计算结果。结果表明，CNCS适用于冷中子精细测量，HYSPEC适用于冷中子-热中子粗略测量，ARCS适用于热中子-超热中子中等Q ω和大Q范围测量，SEQUOIA适用于热中子-超热中子精细测量。
Four direct geometry spectrometers are planned for the SNS. The CNCS is a multiple chopper instrument that uses cold neutrons. The HYSPEC spectrometer uses disc choppers and a vertically focusing monochromator to select cold and thermal neutrons. The ARCS spectrometer is a Fermi chopper instrument with a large angular coverage that uses thermal to epithermal neutrons. The SEQUOIA spectrometer is a Fermi chopper instrument with a long final flight path that uses thermal to epithermal neutrons. To compare the performance of these four instruments, each one has been simulated using the McStas Monte Carlo package. The resulting calculations of flux on sample are compared for various incident energy (Ei) and energy resolution (∆ω) conditions. The results show that the CNCS is optimized for fine ∆ω measurements using cold neutrons, HYSPEC is optimized for coarse ∆ω measurements using cold to thermal neutrons, ARCS is optimized for moderate ∆ω and large Q range measurements with thermal to epithermal neutrons, and SEQUOIA is optimized for fine ∆ω measurements with thermal to epithermal neutrons.