DOSIMETRIC FEATURES OF NATURAL FLUORITE FROM ROMANIA

Thermoluminescent dosimetric features of two batches of fluorite from Romania (Cavnic and Tulcea) are presented. An initial thermal treatment at 6000C for 60 min. to cleaning of natural dose has been performed. All samples showed the same glow curve structure with three prominent peaks located at 1000, 1800 and 2800C at a heating rate of 50C/s. An attempt was made to determine the kinetic parameters of TL glow curve. The activation energy E ~ 1.31 eV (Tulcea batch) of the dosimetric peak and the kinetic order b=2 were obtained. The dose response of CaF2:nat from Tulcea to gamma-rays is linear in the range 2 Gy to 5·103Gy, where saturation effects became pronounced. A thermal fading of 18% during 30 days was observed.