Validation of energy-weighted algorithm for radiation portal monitor using plastic scintillator

•Energy spectra of 133Ba, 137Cs, 22Na, and 60Co were measured by a plastic scintillator.•All energy spectra were converted to energy weighted spectra having clear peaks.•Compared with theoretical value, the peaks have a maximum error of 6%.•For validation, measurement with distance and shielding was also evaluated.

To prevent illicit tracking of radionuclides, radiation portal monitor (RPM) systems employing plastic scintillators have been used in ports and airports. However, their poor energy resolution makes the discrimination of radioactive material inaccurate. In this study, an energy weight algorithm was validated to determine 133Ba, 22Na, 137Cs, and 60Co by using a plastic scintillator. The Compton edges of energy spectra were converted to peaks based on the algorithm. The peaks have a maximum error of 6% towards the theoretical Compton edge.