Evaluation of sodium activation distribution in the PMMA water phantom after fast neutron irradiation

• We conducted experimental evaluation of Na activation distribution in the PMMA.
• Fast neutrons were produced by a 9Be(p, n)9B reaction in MC-50 cyclotron.
• The PMMA containing the NaCl solution was irradiated by fast neutrons.
• Activation distribution was evaluated after correction with the activity ratio.
• We analyzed Na-24 activity differences according to the position in the PMMA.

24Na produced by the neutron activation of stable sodium in the body is commonly used to assess neutron doses after criticality accidents. However, the 24Na distribution is not uniform owing to the interaction with the human body. In this study, we experimentally evaluated the 24Na distribution in a PMMA water phantom and 60 polyethylene vials. The vials were analyzed to evaluate the sodium activation distribution in the PMMA water phantom by employing a correction factor.