Development of portable thermoluminescence measurement equipment for geothermal exploration

A new, portable, and desk-top type of thermoluminescence (TL) measurement system has been developed for mineral analysis in geothermal exploration. The equipment consists of a heater and extremely sensitive photon-detecting and control/recording (PC) units, which can be operated with an ordinary electric current source. A liberated and grained mineral (eg. Quartz) without surface removal by HF treatment is put on the heating pan in a dark box and heated from ambient temperature to 400°C at a constant rate. The TL signal is then detected by the photomultiplier. After detecting the TL, the sample is air-cooled and then continuously re-heated to detect the background luminescence. The glow curve of the sample is obtained by subtracting the background from the original signal. This newly developed TL measurement system makes it possible to measure the TL of minerals in a field-based camp. This development could allow researchers to further evaluate geothermal activity in the field on the basis of TL behaviors of minerals.