Measurement of fluorescence phenomena from yttrium and gadolinium fluors using a 45 MeV proton beam

Abstract In a program to determine proton induced damage and its effect on relative scintillation efficiency for various yttrium and gadolinium based fluors, materials were selected for high efficiency, fast prompt fluorescence response, and minimal delayed fluorescence. These fluors were exposed to a 45 MeV proton beam at the Indiana University Cyclotron Facility (IUCF) using the High Energy Materials Irradiation Chamber (HEMIC). Data obtained at IUCF indicates that the measured 45 MeV proton dose to reduce the fluorescence brightness to half its original value (half brightness dose - N 1 2 ) was found to be 2.2 to 7.3 times larger than that measured at 3 MeV. The corresponding average 45 MeV half brightness dose values, measured at elevated temperature, were 4.0 to 83.7 times larger than at 3 MeV. Although the interaction cross section for 45 MeV protons is smaller than at 3 MeV, each of the resulting high energy reactions causes more damage to the fluor. This research was completed as part of the Fluorescent Materials and Bonding: Extended Energy program under contract DASG60-90-C-0144 for the U.S. Army Space and Strategic Defense Command (USASSDC).