A Monte Carlo study of an energy-weighted algorithm for radionuclide analysis with a plastic scintillation detector

•Radiation portal monitor using plastic scintillator was modeled and the energy spectra of six radionuclides were assessed.•Energy-weighted algorithm which enables radionuclide analysis with plastic scintillator was suggested and evaluated.•The cases of moving and shielding effect were evaluated and simultaneous radionuclide identification was carried out.•Analysis of the simulated spectra with suggested method shows clear results to enable the radionuclide identification.

Nuisance and false alarms due to naturally occurring radioactive material (NORM) are major problems facing radiation portal monitors (RPMs) for the screening of illicit radioactive materials in airports and ports. Based on energy-weighted counts, we suggest an algorithm that distinguishes radioactive nuclides with a plastic scintillation detector that has poor energy resolution. Our simulation study, using a Monte Carlo method, demonstrated that man-made radionuclides can be separated from NORM by using a conventional RPM.