Evaluation of personal dose equivalent "HP (d)" in a external individual monitoring system for X-rays and gamma

Abstract

The good of individual monitoring for external radiation is the assessment of occupational exposure from X and γ radiations in order to assure that the radiological conditions of the workplace are acceptable, safe and satisfactory. The evaluation of radiations doses for workers must not exceed dose limits specified for workers, according to national regulatory agencies. Nowadays, there are two external monitoring systems in use, both based on ICRU definitions. In the conventional system, the workers doses are evaluated in terms of Hx. The personal dosimeter is worn over chest surface and it is calibrated in function of air kerma. In the new system, the workers doses are evaluated in terms of HP(d) and the personal dosimeter is calibrated in function of phantom doses. The aim of this paper is to adapt an external dosimetry laboratory (based on photographic dosimetry) to evaluate the personal dosimeters in terms of HP(d). In this way, a simple methodology, based on linear programming, was utilized. In this adptation, calibration curves were obtained for radiation qualities (W and N series) described by International Organization for Standardization (ISO 4037-1, 1995). These calibration curves offer a better accuracy on dose determinations and energy below 140 keV, improving the quality of service rendered the society.