Abstract: [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%).

Key words: Synchrotron radiation, Small angle X-ray scattering, Beam stabilization, Position sensitive ionization chamber, Experimental physics and industrial control system