Radiation-induced luminescence and hydrogen radical formation associated with thermal annealing treatments on feldspars.

Two kinds of feldspars, such as microcline and albite, were irradiated with g-rays of 250 Gy in 77 K and followed by ESR-measurements at 77 K. First ESR-spectra showed an Al-Oh+ center peak at a centeral part and hydrogen radical peaks having hyperfine (HF) splitting width of 50.2 mT. Second ESR-spectra measured after warming up to room temperature once showed eleven absorption peaks owing to an Al-Oh+-Al center, together with complete disappearance of H0-radicals. The Al-Oh+-Al signals in ESR-spectra showed similar dose response curves in both feldspars, giving almost linear relationships up to several hundred Gy and saturation behavior beyond 1 kGy. Thermal treatment of the feldspars induced an interesting appearance of two new hydrogen radicals in the ESR spectrum, which possess broader HF splitting in the ESR-spectra and relatively stable property at room temperature. The correlation of Al-Oh+-Al centers and the BTL intensities around 180 °C peak showed linear dependency. As a result, it is concluded that the Al-Oh+-Al centers should be main BTL-luminescence centers around the 180 °C peak in the feldspars. [ABSTRACT FROM AUTHOR]