Transient radiation effects in optical materials

The use of the prototype Phermex electron accelerator to simulate high dose rate nuclearradiation environments is discussed. The free electron density produced in optical materials by the beam from this machine, and that expected from a typical incident prompt-gamma radiation flux are compared. An experimental setup to measure the effects on the transmission of selected optical materials is described, and data obtained on these materials are presented. Transient or permanent loss of transmission was observed in optical glasses and GE-101 fused quartz, but no effect was seen in purified fused silica. Reflectivity of front-surface aluminum and dielectric mirrors was also checked and no effects were seen.