CALIBRATION OF A WHOLE BODY COUNTER FOR 241Am WITH THE LLNL CHEST PHANTOM

An occupational incorporation event occurred at the Radioactive Waste Treatment and Disposal Facility in December 2013 at Püspökszilágy, Hungary. Internal contamination due to (241)Am was discovered by a regular routine whole body counting measurement at the Centre for Energy Research, Hungarian Academy of Sciences. After that, a whole body counter was calibrated for an organ counting geometry. For preliminary calibration, a home-made MIX-D chest phantom was applied simulating uniform lung activity distribution by (241)Am point sources located in different positions within the lung volume of the phantom. In order to carry out a more precise calibration, a Lawrence Livermore National Laboratory (LLNL) chest phantom was provided by the International Atomic Energy Agency. For counting efficiency over the lungs, values of 0.46±0.19 and 0.55±0.07 cps kBq(-1) were obtained for the MIX-D and the LLNL phantom, respectively; thus, the results are in good agreement.