Abstract

The wearing time of a individual dosimeter is determined by the maximum possible measuring time within which the dosimeter is in absolute compliance with the PTB requirements. Among others, this maximum measuring time depends on the uncertainty of the natural background radiation in conjunction with the lower measuring range limit for individual dosimeters to measure the penetrating individual dose equivalent Hp(10) of 0.1 mSv demanded in the SSK recommendation "Requirements on individual Dosimeters” of 28 February, 2002. Subtracting a mean value for the natural background radiation, a wearing period of maximum three months would be permissible. A longer wearing time requires more detailed knowledge of the radiation underground (radiation underground while and while not a person wearing the dosimeter). However, in normal operation this would require a considerably higher logistic and financial effort.

The Commission on Radiological Protection therefore recommends that irrespective of the type of the official individual dosimeter, it should be possible to extend the wearing time only to three months basically, in order to comply with the accuracies in official individual dosimetric monitoring prescribed by weights and measures law. Further extensions should only be permitted if a radiation protection supervisor, together with their competent measuring body, can prove a method with higher accuracy. This should be taken into account in the following way in an amendment to the ordinances (StrlSchV, RöV):

“The authority may permit that dosimeters must be handed in to the measuring body in time intervals of up to three months. This term can be extended by the authority by another three months if the requirements on the dosimeters are complied with, taking also into account the characteristics of the radiation fields the individual dose is measured in.”

The Commission on Radiological Protection passed the recommendation “Wearing Times of individual Dosimeters” in the 233rd meeting on 19/20 March 2009.