Neutron Specific Color Center in Fused Silica and an Impurity Band of Identical Wavelength

A color center at 242 m{μ} is produced in certain specimens of fused silica only by pile irradiation and not by x-ray, high energy electron, or proton bombardment. It is removed by heating to 700^∘{}C and can be reintroduced only by pile irradiation. The significance of an impurity absorption band already reported in fused silica at the same wavelength is discussed. An intense band appears in rather pure optical-quality fused germanium dioxide centered at 245 m{μ} and is due to the same reduced germanium species that causes the 242-m{μ} impurity band in fused silica.