Unusual fluorescence emission characteristics from europium-doped lead phosphate glass caused by 3 MeV proton irradiation

In 1951, Birks and Black showed experimentally that the fluorescence efficiency of anthracene bombarded by alphas varies with total fluence (N) as (I/I₀) = 1/(1 + AN), where I is the fluorescence yield, I₀ is the initial light yield, and A is a constant. Schulman observed a similar effect to the Birks and Black equation when organic anthracene was exposed to gamma irradiation. Black later observed no efficiency degradation when the phosphor was exposed to 40 keV electrons, since they only cause ionization damage with no atomic displacements. Broser and Kallmann developed a similar relationship to the Birks and Black equation for inorganic phosphors irradiated using alpha particles. These results indicate that radiation produced quenching centers compete with emission centers for absorbed energy. From 1990 to 2005, the Birks and Black relation described the reduction in emission yield for all fluorescent materials tested by the authors. In 2006, new data indicated the emission yield increased or remained constant when europium-doped lead phosphate glass samples were irradiated with 3 MeV protons. The purpose of this paper is to present the new 3 MeV irradiation results for the europium-doped lead phosphate glass samples.