The new environmental dosimeter for H*(10) measurements

The environmental equivalent dose is intended to serve as a good approximation for an effective dose for a person who is positioned facing any direction within measuring range of the radiation field. In contrast to the old open-air-area-dose-measured-quantity Hx there is now the environmental-equivalent-dose H*(10), defined on a phantom at 10 mm depth in the ICRU-sphere (International Commission on Radiation Units and Measurement).

Therefore the previous Hx-photon-area-dosemeters are not or are only partly usable for measurement the new measured-quantity H*(10). H*(10)-area-dosemeters should indicate the equivalent dose of  enetrating radiation above 15 keV.

DORIS = DOsimeteR for Indoor and outdoor Surveys

Concept

The solution worked out at the GSI Helmholtz Centre for Heavy Ion Research GmbH is based on standard Harshaw-type TLD detector cards placed inside a scattering body made of polyethylene.

Placed inside the dosimeter, two out of four crystals of the TLD card are shielded by a thin copper foil acting as a filter. The combination of the dose measurements of the two detector pairs leads to a response function which very closely resembles the H*(10) measure. The two Cu-filters make possible dosimetry in a very broad energy (10keV to 10MeV) and angular range.

These characteristics represent a significant improvement compared to commercially available solutions. Standard solutions follow the H*(10) function only in a much smaller energy range from about 100keV to 1MeV. As a result of its special design, the dosimeter can be used under almost all weather and environmental conditions.