A 3D In-Phantom Dosimetry System to Estimate the Effective Dose Equivalent

A 3D in-phantom dosimetry system was designed and constructed to provide a means of accurately estimating the effective dose equivalent, HE, for neutron exposure in the workplace. A 40 cm x 40 cm x 15 cm polymethylmethacrylate (tradename Lucite) slab phantom was constructed and superheated liquid droplet detectors (SLDDs) were placed inside the phantom to represent various organ location in the slab phantom. An unmoderated and a D2O-moderated 252Cf source were used to test experimentally the accuracy of the 3D in-phantom dosimetry system in estimating HE. Results of the calculational and experimental estimates of HE based on the ICRP Publication 60 tissue weighting factors were found to agree to within ±35% for both unmoderated and D2O-moderated 252Cf sources incident in the AP, RL, LL, and PA geometries. These results indicate the viability of the SLDD-based in-phantom system in estimating HE from neutron exposure without extensive prior knowledge of the actual neutron fields. (author)