COMPARISON OF THE NEUTRON ENERGY RESPONSE OF TWO DIFFERENT TLD ALBEDO DOSEMETERS

Albedo dosemeters remain the most used dosemeters in neutron individual monitoring. In Brazil, most of the neutron occupational fields are from radionuclide sources, often without any moderation, where albedo dosemeters have poor energy response. The purpose of this work is to compare the HP(10) energy response of the IRD and ALNOR TLD albedo dosemeter systems, calculated by their modelling with Monte Carlo code MCNPX. Their energy responses are similar, as expected, but the IRD system is about five times more sensitive than the ALNOR one. IRD albedo system can measure the Brazilian monthly recording level of 0.2 mSv, even for bare Cf-252 and Am-241-Be neutron fields. On the other hand, the ALNOR system can measure values higher than 0.2mSv only after huge moderation of theses sources. These results show that IRD TLD albedo is more suitable than the ALNOR one to measure low doses at occupational fields from radionuclide sources.