上海光源硬X射线光束在线监测

Online Monitoring of Hard X-Ray Beam at SSRF

设计了一种基于荧光成像的X射线光束在线监测装置,用于上海光源硬X射线光束的实时在线监测。相较于现有位置监测器和气体电离室,该装置能实现2 kHz高速采集,具有实时监测光束位置、通量、尺寸以及重建入射光波前相对变化量的功能,且不会影响下游实验开展。该装置可用于光学器件和实验位置反馈,在超长和微纳聚焦光束线站将有很好的应用。在上海光源时间分辨超小角散射线站的USAXS和微聚焦SAXS实验站利用该装置开展在线监测实验,采集并分析了常用实验帧率下的光束稳定性数据,得到了该线站光束位置、通量、尺寸分布的时频域信号和入射波前的相对变化情况,验证了该装置的可行性。

An online monitoring device is designed for the real-time monitoring of hard X-ray beams at Shanghai Synchrotron Radiation Facility(SSRF). Compared with the existing beam position monitors and gas ionization chambers, it can monitor the beam position, size, and flux, and reconstruct the relative phase variation of the incident wavefront with an acquisition speed of 2 kHz, without affecting the downstream experiments. In addition, it has potential applicability for feedbacks of the optical devices and experimental positions in super-long and micro-nano-focused beamline stations. Experiments are carried out in the USAXS and micro-focusing SAXS experimental stations at SSRF, and beam stability data are collected at common experimental frame rates. The time-frequency domain signals of position, flux, and size distribution of the incident beam are analyzed, and the phase variation of the incident wavefront is obtained as well. Finally, the feasibility of this device is verified.