Measurement and calculation of scattered Synchrotron Radiation processes at the KARA visible light beamline

Abstract

At KARA a visible light diagnostic beamline is in use to analyse the stored electron beam. Synchrotron light is deflected 90 degrees upwards by a cooled copper mirror, passes through a Quartz UHV window and is then reflected back into the horizontal plane but sideways through a hole in the wall to the diagnostics. Based on experience from similar Infrared beamlines no significant radiation (doserates larger than 0.5µSv/hr) was expected. Nevertheless, a higher radiation level exists but can be shielded with 0.3mm Aluminium foil or 2.0mm of Pyrex reducing the rate to an acceptable level. The presence of the radiation led to further investigation by experiment and calculation. A custom setup using a silicon drift detector (SDD) for energy dispersive spectroscopy showed the radiation to be predominantly Copper K-alpha and is confirmed by FLUKA and other calculations of the scattered Synchrotron radiation.