Results of Recent Phantom Backscatter Studies
S.O. Schwahn (US Department of Energy)
The Department of Energy Laboratory Accreditation Program (DOELAP) recently corrected external dosimetry performance testing data from its Am-241 (59 keV photon) whole body irradiations. The corrections were made as a result of investigations into apparent negative bias in the performance testing results of DOE facilities. Studies indicate that the largest contributor to the bias is variations between polymethylmethacrylate (acrylic) phantoms. Though exact causes for the variations have not been fully explained, there is a correlation between the apparent age of the phantom and the measured backscatter.