IMPLEMENTATION AND TEST OF A SYNCHROTRON RADIATION POSITION MONITOR AT A USER BEAM LINE

A slotted plate photodiode beam position monitor was built and installed on a user beam line. The detector is positioned in front of the first optical component of the beam line intercepting approximately 3 mrad of synchrotron radiation. A 25-mu-m-thick Be foil strongly attenuates photons with h-nu < 800 eV and improves the position sensitivity by reducing the vertical angular divergence of the effective photon beam by more than a factor of 10. With a 125-mu-m gap at 45-degrees angle between the diode plates, the detector has a linear working range of approximately +/- 800-mu-m. The vertical position sensitivity of the beam position monitor is approximately 5-mu-m.