Environmental dosimetry using high-sensitivity TL detectors

Two highly sensitive thermoluminescent (TL) materials (Al2O3:C and CaSO4:Tm) were investigated for environmental monitoring. We compared their response to low and to high linear energy transfer (LET) radiations in order to develop a two-element TL system.The relative TL efficiency for α-particle irradiation as compared to γ-exposure was about 0.04 and 0.5 for Al2O3:C and CaSO4:Tm, respectively. Measurements of external environmental radiation doses in an international balloon experiment were performed with our highly-sensitive TL system having various sensitivities to low and to high LET radiations.