Fading in CaF/sub 2/(Tm/Dy) TL phosphors used in environmental radiation monitoring

The TL (thermoluminescence) stability of CaF/sub 2/:Dy (TLD-200) and CaF/sub 2/:Tm (TLD-300) has been investigated over a maximum of 900 hours of storage. The experiments were carried out in different climatic conditions of storage: storage in dry air at 30, 40 and 46 degrees C; and storage in humid conditions at 30 degrees C and 80% RH, 40 degrees C and 80% RH, and 46 degrees C and 80% RH. Among other findings, it is shown that CaF/sub 2/:Tm is suitable as an environmental dosimeter material because of its insensitivity to the ambient conditions.<
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