上海光源小角X射线散射线站光束稳定性研究

Study on X-ray beam stabilization of BL16B1 at SSRF

在同步辐射光源,实验站光束稳定性是衡量光束线的重要指标,它是用户获得高质量实验数据的前提。为了评价上海光源小角X射线散射实验站(BL16B1)光束稳定性,首先在样品台附近安装用于检测光束中心位置和光束强度的IC-500-50位置灵敏电离室,同时使用CAENels公司的TetrAMM四象限皮安计实时检测IC-500-50电流,然后通过移动Kohzu垂直方向电机改变电离室与入射光束的相对位置,从而测试IC-500-50的线性范围和灵敏度等主要性能参数,最后通过静止保存电流值计算光束中心位置并最终得到BL16B1光束稳定性指标。测试结果表明:BL16B1垂直方向光束中心位置抖动的标准偏差为0.8%,光强抖动的标准偏差为0.44%,最终计算分析得知1%之内的不稳定性满足光束线稳定性设计指标(10%之内)的要求。

[Background] The beam stability is very important to each beamline at synchrotron radiation facility, it is the premise for users to obtain high-quality experimental data. [Purpose] This study aims to test the beam stability of BL16B1 at Shanghai synchrotron radiation facility (SSRF) by the beam position monitor (BPM) which is used to detect the beam center position and intensity. [Methods] The IC-500-50 position sensitive ionization chamber is installed near the sample stage, the real-time current is measured by the TetrAMM 4-channel fast interface bipolar picoammeter made by CAENels company. The position sensitivity and linearity of IC-500-50 and the beam stability of BL16B1 are measured by changing the relative position of the ionization chamber and the incident beam. [Results] The results show that the standard deviation of the center beam position of the beam along the vertical direction is 0.8%, and the standard deviation of the light intensity is 0.44%. [Conclusion] The analysis shows that the instability within 1% meets the design requirements of beam stability (within 10%).