Movable radiation shields for the CLEO II silicon vertex detector

Abstract Two movable tungsten radiation shields were installed on the beam pipe during the upgrade of the CLEO II detector, operating at the Cornell Electron Storage Ring (CESR). This upgrade included the installation of a silicon vertex detector (SVX) and the purpose of the shields is to protect the SVX readout electronics from synchrotron radiation produced during injection and non-high-energy physics operation of CESR. Shield motion is controlled remotely by cables, keeping the associated motors and controls outside the detection volume. We discuss the design and performance of the radiation shields and the associated control system.