On the Purple and Violet Light Emissions in Thermoluminescing Quartz

Abstract

New emissions in some thermoluminescing natural quartz are observed. It is found that short bursts of a few seconds of purple and violet lights are produced following the ususal greenish–blue upon quenching the quartz crystals and irradiating with relatively light doses of γ‐rays. Quenching is done from 400°C to water at room temperature. The new emissions are emitted at 112 and 120°C and seem to be due to release of electrons trapped in extended defects (shown up by ESR) caused by quenching. Due to low enough energy of activation of trapped electrons (0.0332 and 0.0338 eV) causing these emissions, the latter are not produced if such crystals are stored for some time (≈ one month). On re‐irradiation of the samples, the emissions can be reobtained.

Radiation induced modification of impurity-related point defects in crystalline quartz – a review

“…The radiation-induced defects thermally anneal by 700 K and in the process give out therolumniscence which is generally in the greenish-blue region [7]. In some cases, purple and red emissions have also been observed [13]. Interestingly, it would be instructive to mention here that while the protons in quartz are mobile at all temperatures down to 10 K, the movement of alkalis start only when the temperature of sample under investigation is about or above 200 K. Thus, upon irradiation at 77 K only protons move; they come to rest, most in shallow and some in deep traps.…”