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

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″×2″ 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 determined using MC and experimental measurements. A self-developed software was used to acquire and analyse the gamma spectra. In addition, Minimum Detectable Activity Concentrations were calculated for 137Cs and 131I. 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. After its set up and calibration, the system was tested on the field and provided adequate results. Therefore, the mobile unit is available to assist in the event of a nuclear emergency tracking radioactive plumes and participating in radioisotope mapping surveys. It is also ready to obtain the required data to build the radiological map of Catalonia.