Applicability of a portable system of in situ gamma-ray and X-ray spectrometry

In this work it was studied the application of an in situ gamma spectrometer (ROVER) of Amptek Inc., composed by a Cadmium Telluride detector (CdTe) of 3 mm x 3 mm x 1 mm and a 30 mm x 30 mm Sodium Iodide detector doped with Thallium [NaI (Tl)]. The certified radioactive sources used in the work were type pastille, sealed in aluminum and polyethylene, of 241Am, 133Ba, 137Cs and 152Eu. With these radioactive sources it was determined the efficiency curve and the Minimum Detectable Activity (MDA) for the two detectors. For the line of 32 keV of the 137Cs to 4.15 cm of the detector of CdTe, MDA is of 15 kBq. For the detector of NaI (Tl), analyzing the line of 661.65 keV from the 137Cs to 100 cm of distance, AMD is of 17.6 kBq. In function of the determined AMDs, we concluded that the employed spectrometer allows the quantification of the activity of radioactive sources of 137Cs with activities same or superior to 15 kBq and 17.6 kBq, respectively for the detectors of CdTe and NaI (Tl), and analyzing the efficiency curves, we can also determine MDA for other interest of radionuclide. (author)