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

Abstract

BackgroundThe 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.PurposeThis 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).MethodsFirstly, 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.ResultsThe 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.ConclusionsProposed automatic calibration system simplifies the optical path optimization of experimental station and improves the automation of the SAXS beamline station at SSRF.

Keywords

• synchrotron radiation
• epics
• saxs
• genetic algorithm
• automatic beamline alignment system