MEASUREMENT OF FLUORESCENCE PHENOMENA FROM YTTRIUM AND GADOLINIUM FLUORS USING A 45-MEV PROTON-BEAM

In a program to determine proton induced damage and its effect on rela tive scintillation efficiency for various yttrium and gadolinium based fluors, materials were selected for high efficiency, fast prompt fluo rescence response, and minimal delayed fluorescence. These fluors were exposed to a 45 MeV proton beam at the Indiana University Cyclotron F acility (IUCF) using the High Energy Materials Irradiation Chamber(HEM IC). Data obtained at IUCF indicates that the measured 45 MeV proton d ose 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 rimes larger than that measured at 3 MeV. The corresponding average 45 MeV half bri ghtness dose values, measured at elevated temperature, were 4.0 to 83. 7 times larger than at 3 MeV. Although the interaction cross section f or 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 c ompleted as part of the Fluorescent Materials and Bonding: Extended En ergy program under contract DASG60-90-C-0144 for the U.S. Army Space a nd Strategic Defense Command (USASSDC).