Electronics for SPring-8 X-ray beam monitors

A sensitive current-measuring system is required to construct a highly sensitive X-ray beam-position monitor (XBPM). A current-voltage converter (I/V) which can measure currents between 0.1 nA and 10 mA was designed, and the signal processing system of the XBPM was constucted using this I/V. This system was used in beamline commissioning. Beam-position data standard deviations of sigma approximately 3 micro m for the bending-magnet beamline, and sigma(x) approximately 3 micro m and sigma(y) approximately 1 micro m for the insertion-device beamline were obtained during the beamline commissioning.