PERSONNEL NEUTRON DOSIMETRY IMPROVEMENTS AT LOS-ALAMOS-NATIONAL-LABORATORY

Methods are being investigated to improve neutron dosimetry at Los Ala mos National Laboratory (LANL) using the etched track dosemeter CR-39. Specifically, use of CR-39 for dynamic environments, typically encoun tered at the LANL Plutonium Facility, is shown to be a superior method for personnel neutron dosimetry when compared to the currently used T LD system. The results of glovebox experiments simulating hydrogenous shielding used at LANL, temporal variations of neutron correction fact ors used at the Plutonium Facility, trial implementation at this facil ity and preliminary neutron spectroscopy measurements are presented an d compared to reference dosimetry measurements. The results confirm th at use of a TLD system in a facility implementing hydrogenous shieldin g requires frequent field recalibration. When such correction factors are not re-evaluated frequently, or are maintained at pre-shielding le vels, significant (i.e. 2-to 3-fold) overestimation of the neutron dos e equivalent can occur.