The effect of gravity on the resolution of small‐angle neutron scattering
The effect of gravity on the resolution of small‐angle neutron scattering
复制标题
重力对小角中子散射分辨率的影响
DOI：
10.1107/s0021889888014736
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
A. Boothroyd
中科院分区：
文献类型：
--
作者：
A. Boothroyd
在小角度衍射仪中，中子在重力作用下下落的距离并不总是可以忽略不计。如果数据是相对于机器轴而不是相对于散射图案的真实中心进行分析的，就像白光束脉冲源仪器的情况一样，那么与零重力光谱相比，测量到的光谱将会失真。结果表明，这种重力效应可以被视为对仪器分辨率的贡献，并且计算了重力分辨率函数的解析形式。给出了散射矢量的均值和方差，并对典型实验条件下问题的严重性进行了数值估计。对于当前使用的大多数仪器，重力对 Q 分辨率的贡献预计不会超过 5%。
The distance through which neutrons fall under gravity in a small-angle diffractometer is not always negligible. If the data are analysed with respect to the machine axis rather than with respect to the real centre of the scattering pattern, as might be the case on white-beam pulsed-source instruments, then the measured spectrum will be distorted compared with the zero-gravity spectrum. It is shown that this gravity effect may be treated as a contribution to the resolution of the instrument, and an analytic form for the gravity resolution function is calculated. The mean and variance of the scattering vector are given, and numerical estimates are made of the severity of the problem under typical experimental conditions. For most instruments in current use the gravity contribution to the Q resolution is not expected to exceed 5%.