Development and testing of a mixed neutron-photon-beta field thermoluminescent dosimeter for personnel monitoring

A new four element Lithium Fluoride (LiF) badge and analysis algorithm have been developed and tested to better characterize personnel exposure in mixed radiation fields. The new badge is based on a commercially available chip card with three 7LiF elements and one 6LiF element. The badge holder is also based on a commercially available design, with modified filtration elements. The new algorithm takes advantage of the high temperature peak characteristics of the 6LiF element to better quantify neutron dose. The prototype badge was tested by using various mixtures of two fields typically used for dosimeter performance testing, as well as mixtures of three fields to better simulate actual operating conditions. The badge gave superior performance, based on the tolerance levels, when using the new algorithm as compared to an algorithm that did not use the high temperature peak methodology. The badge and algorithm are limited in that the approximate energy spectra of the neutron and beta field components must be characterized in advance