Set up of a gamma spectrometry mobile unit equipped with LaBr3(Ce) detectors for radioactivity monitoring

Abstract This paper presents the development, calibration and testing of a mobile unit for radioactivity monitoring. A 4 × 4 vehicle was equipped with a GPS and two 2″x2″ LaBr3(Ce) scintillation detectors. It was modelled using MC simulations with the EGS5 code to obtain efficiency curves for different source term scenarios. The attenuation produced by the car structure was also determined using experimental measurements. A self-developed software was used to acquire and analyse the gamma spectra. Minimum Detectable Activity Concentrations were calculated for 137Cs and 131I. After its calibration and testing, the mobile unit is available to track radioactive plumes and to participate in radioisotope mapping surveys in the event of a nuclear emergency. During standard operation, the mobile unit will create a radiological map of Catalonia (Spain), calculating in real time the ambient dose equivalent H*(10) and the activity concentration of natural and anthropogenic radionuclides. The system was tested on the field and provided adequate results. Therefore, the mobile unit is ready to assist in nuclear emergencies and to obtain the data for the radiological map of Catalonia.