High-Dose-Level Glass Dosimeters with Low Dependence on Energy

Glass dosimeters with low dependence on energy (< ± 20% between < 10 keV and several MeV) have been made by activating lithium borates (Li₂O, xB₂O₃, x = 2 − 4) with small amounts (≤ 0.5%) of silver. The radiation-induced absorption spectrum between 250 and 400 nm is more complex than in a commercial Ag-activated phosphate glass. Several peaks undergo a buildup prior to fading. At, and above, room temperature, the optical absorption, in particular for peaks <300 nm, is considerably more stable than in the phosphate glass (in one borate glass, for example, the absorption at 278 nm is constant within ± 12% for 10 h at 200°C). The absorption spectrum after thermal-neutron radiation is different from the gamma-radiation-induced spectrum. The density is a linear function of exposure.