Radioluminescence of solid neodymium-doped laser materials excited by α-particles and fission fragments

The characteristics of radioluminescence of Nd³⁺ : Y₃Al₅O₁₂ crystals and laser glasses under excitation by plutonium-239 (²³⁹Pu) α-particles, as well as by α-particles and spontaneous fission fragments of californium-252 (²⁵²Cf), are studied. The radioluminescence branching ratios β_ij for the transition from the ²F2_5/2 level to the ^2S+1L_J levels in Nd³⁺ : Y₃Al₅O₁₂ crystals are measured. Radioluminescence from the ²P_3/2 level to low-lying levels is observed. The β_ij ratios for transitions from the high-lying ²F2_5/2, ⁴D_3/2, and ²P_3/2 levels are theoretically calculated. The lifetimes of metastable levels of Nd³⁺ excited by ²⁵²Cf fission fragments are measured. The efficiency of the conversion of energy of α-particles and fission fragments to the energy of optical radiation of Nd³⁺ : Y₃Al₅O₁₂ crystals and laser glasses is determined.