On the use of LiF TLD-600 in neutron-gamma mixed fields

Full text: A new procedure allowing the separate estimation of neutron and gamma dose in mixed radiation fields have been developed in our laboratory. In this communication a description of the main features of the discrimination procedure and some preliminary results obtained by its use are presented. The procedure is based on the significantly different structure of the glow curve of LiF TLD-600 produced by neutron and gamma radiation. The use of peak resolving numerical methods, sometimes called deconvolution, for the analysis of the glow curves from controlled irradiations at absorbed doses in the range 10-300 mGy with different neutron and gamma proportions, permits to quantify the differences peak by peak, also characterizing the well known neutron quasi-exclusive contribution to the high temperature region, above peak 5. From this study it was possible to propose a n/γ TL factor by which the respective doses can be estimated by a simplified analysis, not peak resolving, of the particular features of the glow curves obtained in field measurements. A first set of rather satisfactory results have been obtained by irradiating TLD-600 together with TLD-700 chips using Am-Be sources with different degree of moderation and using lead absorbers to change the gamma component. This component is directly measured by the TLD-700 detectors allowing testing the gamma estimation reached by the discrimination procedure applied to the TLD-600 glow curve. (author)