Identification of Effective Parameters and their Relations for Normalization of Radiation Profiles from Radiation Portal Monitors for Initial Alarm Assessment at the Ports of Entry

In order to detect radioactive material out of regulatory control (MORCs), radiation portal monitors (RPMs) have been established in designated and undesignated ports in many countries. Following the radiation profile produced by the RPMs, the front-line officers (FLOs) at the alarm station have to make an accurate decision to determine whether it is a true alarm or not. In certain situations, they may have to request for secondary inspection of the cargo container. If the FLO is inexperienced, the identification might be a challenge. Also, requesting for secondary inspections from an external organization (expert assistance) can be a slow process with many administrative burdens. The unnecessary delays of the cargo clearance directly decrease the operation efficiency and quality of service of the port. In order to rectify this, the International Atomic Energy Agency (IAEA) has introduced TRACE (Tool for Radiation Alarm and Commodity Evaluation) mobile app to assist the FLOs to produce accurate decisions with higher efficiency. To develop the application further, it is necessary to identify all the parameters affecting the radiation profile generated by the RPM. As a member of the Coordinated Research Project (CRP) on Improved Assessment of Initial Alarms from Radiation Detection Instruments (J02005), Sri Lanka has done several experiments and has identified the effective parameters on radiation profile. Carrier speed, Geometrical and background variations, the mass of the commodity and efficiency of detectors directly affect the shape and the sigma level of the profile. The paper presents the findings of these experiments and a preliminary analysis of data for further development of the TRACE app and overall development of alarm assessment procedures.