beta-irradiation induced TL characteristics of Nigerian fluorite

The potentials of Nigerian fluorite (CaF2:N) as a thermoluminescent dosimeter for environmental monitoring had been investigated. The glow curves of CaF2:N exhibits three peaks (PI, PII, and PIII) recorded at 111 ± 11oC (PI), 196 ± 2oC (PII), and 282 ± 4oC (PIII). For PII and PIII, a linear response to beta-ray was observed up to 72 mGy. The activation energy of the low-temperature peak was extracted from the glow curves to be 0.85 ± 0.17 eV and 0.99 ± 0.03 using the variable heating rate (VHR) and the initial rise (IR) methods, respectively. The frequency factor and the lifetime of the charge carriers in the metastable state for PI were both evaluated using the VHR method to be (3.66 ± 0.90) × 1010 s-1 and 12 ± 5 s, respectively. CaF2:N was found to be about 30 times more sensitive to beta-ray than TLD100. It also yielded an appreciable response upon fluorescent and daylight exposure for 5h while TLD100 was found insensitive to both lights. Peak PI faded as much as 62% for the 43 days of storage while no specific pattern was recorded for PII and PIII. A build up was suspected to have occurred in irradiated fluorite which was attributed to the likely presence of 90Y.

Autorentext
Bakary Latif, MouftahouDr. Mouftahou Bakary Latif holds a Ph.D. in experimental nuclear physics from the University of the Witwatersrand, Johannesburg, South Africa. He researches actively in the area of radiation physics, applied nuclear physics, and nuclear structure with a special interest in the study of giant resonance modes in nuclei across the periodic table.