BONE EQUIVALENT CALCIUM-CONTAINING PHOSPHATE-GLASS FOR RADIATION-DOSIMETRY USING OPTICAL-ABSORPTION

A newly developed Ca-Al-Na-phosphate glass dosimeter was studied for i ts spectral sensitivity to ionizing photons in the range 0.1 MeV to 10 MeV. The dosimeter is colorless before exposure to ionizing radiation and then takes on an reddish color upon increasing irradiation with C o-60 gamma rays. Three radiation-induced bands are observed in the spe ctra of irradiated glasses. The first is in the UV region (180-300 mm) and the other two bands are in the visible region (450-600 nm). The c hange in absorbance is linear up to 2 kGy and then tends to saturate f rom 2 to 8 kGy, when measured at its 496 nm absorption band maximum. T he new glass dosimeter simulates compact bone in terms of gamma-ray ab sorption properties over broad radiation spectra. It has a relatively small energy dependence and can also be use-d for food irradiation dos imetry. The stability of color centers formed upon irradiation was stu died at normal laboratory storage conditions and the spontaneous deexc itation of the glass is about 37% in 25 days.