Application of TLD dosimeters (CaSO₄:Dy and LiF:Mg,Ti) for environmental assessment of H*(10) in field studies.

Abstract

The increasing use of ionizing radiation across various sectors of society underscores the need for effective monitoring of occupationally exposed individuals (OEIs), the public, and the environment. Within this framework, environmental radiation protection programs adopt the ambient dose equivalent H*(10) as the operational quantity, as defined by the International Commission on Radiological Protection and recommended by the International Atomic Energy Agency, due to its suitability for estimating the risk of external exposure under field conditions. This study assessed the ambient dose equivalent H*(10) through a field survey conducted around the perimeter of the IPEN facilities. Eight monitoring points were selected near thirteen already existing environmental sampling stations, covering approximately 60% of the area. The monitoring was structured in three stages: (i) a comparative analysis between monthly and quarterly measurements using CaSO₄:Dy thermoluminescent detectors (TLDs), which showed proportional responses; (ii) a comparison between quarterly measurements with CaSO₄:Dy and LiF:Mg,Ti TLDs, which demonstrated equivalent results; and (iii) a comparison between the quarterly CaSO₄:Dy data from this study and those obtained in the Environmental Radiological Monitoring Program of the Center for Metrology of Ionizing Radiations of IPEN (ERMP/CEMRI-IPEN), which indicated consistent and satisfactory results, confirming the reliability of using H*(10) in the applied monitoring system. Statistical and uncertainty analyses further confirmed the robustness of environmental monitoring with thermoluminescent dosimeters. Proper detector selection remains essential to ensure accuracy, minimize variability, and enhance environmental radiation monitoring programs.