Gadolinium oxysulfide doped with terbium was exposed to 45 MeV proton irradiation in the specially designed High Energy Materials Irradiation Chamber at the Indiana University Cyclotron Facility. This exposure was accomplished to determine the functional relationship between sample temperature and fluorescence intensity. Luminescent intensity dropped to half of the measured 113°C value at a temperature of 133°C. This effect was analyzed to determine the activation energy for radiationless transition. This result will provide a good understanding of the radiation hardness and spectral response for this fluor for possible use in the future development of a high energy accelerator beam positioning system.