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

Area of Science:

• Nuclear physics
• Occupational health
• Radiological protection

Background:

• An occupational internal contamination incident involving Americium-241 occurred at a Hungarian radioactive waste facility in December 2013.
• Routine whole body counting at the Centre for Energy Research detected the contamination.

Purpose of the Study:

• To calibrate a whole body counter for organ counting geometry.
• To ensure accurate internal dose assessment following occupational exposure.

Main Methods:

• Preliminary calibration utilized a home-made MIX-D chest phantom with Americium-241 point sources to simulate lung activity.
• A Lawrence Livermore National Laboratory (LLNL) chest phantom, supplied by the IAEA, was used for more precise calibration.
• Counting efficiencies for lung activity were determined using both phantoms.

Main Results:

• Counting efficiency values of 0.46±0.19 cps/kBq and 0.55±0.07 cps/kBq were obtained for the MIX-D and LLNL phantoms, respectively.
• The results from both phantom calibrations showed good agreement, validating the calibration process.

Conclusions:

• The study successfully calibrated a whole body counter for organ counting geometry.
• The use of both MIX-D and LLNL phantoms provided reliable data for internal contamination monitoring.
• Accurate calibration is crucial for effective radiological protection in occupational settings.