曲面切槽晶体单色器性能分析与测量

Analysis and measurement of performance for the channel cut-curved crystal monochromator

本文给出了用于同步辐射分光谱仪中的曲面切槽晶体衍射性能的理论计算和实际测量。通过与常规对称结构的双平晶衍射比较分析,影响曲面晶体衍射效率、衍射角宽和束斑漂移的主要因素是曲面晶体在光束照射区内斜切系数的变化率以及两工作曲面对Bragg转轴的定位偏差。指出提高曲面形状制作精度、减小定位误差、增大曲面切槽晶体的尺寸是改善曲面晶体衍射性能的有效途径。

Performance of the synchrotron radiation monochromator of a channel-cut crystal with curved surfaces has been analyzed and measured. Comparing with conventional symmetric double-flat-crystal, we found that the throughput, bandwidth and beam exit stability of the channel cut-curved crystal were mainly affected by the asymmetric reflections of the extended beam and the Bragg axis deviation from exact position. It was concluded that the monochrornator＇s performance could be improved by enlarging dimensions of the reflecting surfaces, and improving precisions of the profiles machined and the Bragg axis positioned for the channel cut-curved crystal.