Annealing Behavior of Emission Bands Induced by Neutron Irradiation in Silica Glass.

Abstract

The continuously emitting 4.2 eV, 3.2 eV and 1.9 eV photoluminescence (PL) bands were measured for as-manufactured and neutron-irradiated silica glasses. In the as-manufactured sample, the intensity of the 4.2 eV decreased with increasing temperature from 77 K to 550 K. The 3.2 eV band observed at room temperature was too weak to be observed at 77 K, and the intensity increased till 80 °C, and decreased above 110 °C. In the neutron irradiated sample, the intensity of the 4.2 eV PL band increased, and the peak position shifted to 4.37 eV. After annealing to 600 °C, the intensity at room temperature became weaker than the original, and the peak position continued to shift to higher energy side. On the other hand, the intensity of the 3.2 eV PL band decreased drastically and almost disappeared, and any shifts of the peak position were not observed. After annealing to 700 °C intensity at room temperature began to increase, and the peak position kept the original position. The 1.9 eV PL band was observed after neutron irradiation, and depended on the OH content in the as-received samples. After annealing, the intensity of the 1.9 eV band increased gradually up to 450 °C and then decreased and almost disappeared at 700 °C.