上海光源小角X射线散射实验站自动校准系统研究

Automatic calibration system of small angle X-ray scattering experiment station at SSRF

小角散射实验站用户获取的实验数据质量与实验站的光路优化状态(较低的散射背景、准确的样品前后光强计数等)密切相关。目前小角散射实验站光路优化是手动优化方式,不利于用户机时的有效利用。在实验物理与工业控制系统(Experimental Physics and Industrial Control System,EPICS)和控制系统工具箱(Control System Studio,CSS)平台下,使用Python语言设计并开发了光路优化自动校准程序,通过狭缝刀口扫描确定直通光中心位置,根据遗传算法的单目标和多目标优化方法自动优化,得到较低的空气背底散射图像,最终完成调光。测试结果表明:自动校准程序可以在30 min内完成实验站单色光狭缝和束流阻挡器位置调试,简化了实验站的光路优化工作,提高了小角散射实验站的自动化程度。

[Background]The quality of the experimental data is closely related to the optimal optical conditions of the end-station in the small-angle X-ray scattering(SAXS)beamline(lower scattering background,accurate beam intensity before and after the sample,etc.).At present,the optical conditions of the end-station are manually optimized in SAXS beamline(BL16B1)of shanghai synchrotron radiation facility(SSRF),which can not utilize the user's time effectively.[Purpose]This study aims to design and implement an automatic calibration procedure with Python on the platform of EPICS(experimental physics and industrial control system)and CSS(control system studio).[Methods]Firstly,the direct beam was searched and targeted using slit blades scanning,and then beam center was automatically optimized according to the single-objective and multi-objective optimization methods of genetic algorithm,the calibration is not completed until an optimal scattering background image is obtained.[Results]The results show that the automatic beamline calibration system can complete the motors optimization of slits and beamstop in 30 min,much faster than manual operation.[Conclusions]Proposed automatic calibration system simplifies the optical path optimization of experimental station and improves the automation of the SAXS beamline station at SSRF.