浦项加速器实验室光束线“扫帚柄”双晶单色仪快速扩展X射线吸收精细结构扫描的设计与可行性

Design and feasibility of quick EXAFS scans for a 'broomstick' double-crystal monochromator at PLS beamline.

作者信息

Lee J M, Sung N E, Park J K, Yoon J G, Kim J H, Choi M H, Lee K B

机构信息

Beamline Research Division, Pohang Accelerator Laboratory, POSTECH, Pohang 790-784, Korea.

出版信息

J Synchrotron Radiat. 1998 May 1;5(Pt 3):524-6. doi: 10.1107/S0909049598000831.

DOI:10.1107/S0909049598000831

PMID:15263566

Abstract

A data-collection technique for quick extended X-ray absorption fine-structure spectroscopy (QEXAFS) was developed with a new 'broomstick' double-crystal monochromator, which has been installed for X-ray absorption fine-structure (XAFS) applications at the Pohang Light Source. The monochromator operates in a fixed-exit scan mode as the Bragg angle is varied from 8 to 80 degrees, corresponding to 2-14 keV, using an Si(111) crystal. The monochromator scan capability was investigated by analysing EXAFS data quality from step-scan and from continuous rotation of the Bragg crystal reflection angle. In our fast continuous-scan design, the electronic pulsing speed of the step motor is adjustable to avoid the monochromatic beam instability caused by serious mechanical resonance. The feasibility of QEXAFS scanning is demonstrated by a typical EXAFS scan (e.g. 1 keV range) being taken within 1 min.

摘要

利用一种新型的“扫帚柄”双晶单色仪开发了一种用于快速扩展X射线吸收精细结构光谱（QEXAFS）的数据收集技术，该单色仪已安装在浦项光源用于X射线吸收精细结构（XAFS）应用。该单色仪在固定出射扫描模式下运行，当使用Si(111)晶体时，布拉格角从8度变化到80度，对应于2 - 14 keV。通过分析步扫描和布拉格晶体反射角连续旋转时的EXAFS数据质量，研究了单色仪的扫描能力。在我们的快速连续扫描设计中，步进电机的电子脉冲速度是可调的，以避免由严重机械共振引起的单色光束不稳定性。通过在1分钟内完成典型的EXAFS扫描（例如1 keV范围）证明了QEXAFS扫描的可行性。