Detection of \v Cerenkov Light with Wavelength Shifting Plastic -- A Beam Test

The collection efficiency for \v Cerenkov light incident on a wavelength shifting plate has been determined during a beam test at the proton synchrotron at KEK. An efficiency of roughly 50\% has been determined for photons created in a fused silica radiator in front of an acrylic plate that contained a wavelength shifting fluorescent substance. The experimental procedure and the results will be presented together with possible applications for \v Cerenkov detectors.