Luminescence properties of biotite relevant to dating and dosimetry

Biotite mineral grains from granitic rocks were subjected to luminescence studies with optical and thermal stimulation. Moderate thermoluminescence (TL) signals and weak optically stimulated luminescence (OSL) with blue-green light stimulation were detected after 50 Gy beta irradiation. No detectable infrared-stimulated luminescence (IRSL) was observed for natural and laboratory beta-irradiated samples. TL peaks at 118, 300, 360 and 480 °C can be identified from laboratory-irradiated samples. The 360 °C TL peak saturates at a higher dose than quartz, but shows significant anomalous fading after 80 days stored at room temperature. The potentials and problems for biotite used as a natural dosimeter are discussed.