μDose: A compact system for environmental radioactivity and dose rate measurement

μDose is a novel compact analytical instrument for assessing low level 238U, 235U, 232Th decay chains and 40K radioactivity. The system is equipped with a dual α/β scintillator allowing discrimination between α and β particles. The unique built-in pulse analyzer measures the amplitude of each individual pulse, its shape and the time interval between subsequent pulses. This allows the detection of pulse pairs arising from subsequent decays of 214Bi/214Po, 220Rn/216Po, 212Bi/212Po and 219Rn/215Po. The obtained α and β counts and four separate decay pair counts are used to calculate 238U, 235U, 232Th and 40K specific activities in measured samples through the use of radioactivity standards. The μDose system may be equipped with various photomultipliers and counting containers to assess radionuclide concentrations of samples of masses ranging between 0.4 g and 4 g. As a result, the user can customize the system to their needs and maximize the instrument's performance. The system is controlled by dedicated software with a graphical user interface and modules for system calibration, data visualization, specific radioactivity calculations and dose rate determination using the infinite matrix assumption.