Intensity variation of gamma radiation on ground level interface in São Jose Dos Campos, SP, Brazil

Abstract

In the period June 22 to September 24, 2012 São José dos Campos region experienced dry climate with low relative humidity. The net rain intensity measured in this period was 60 mm/h and the relative humidity range between 30% to 40% on most days. The intensity of gamma radiation from 0.03 to 10.0 MeV, in the measurement period presents a daily fluctuation well clearly, and some small increases when there is rainfall.  These measures were realized at ITA's campus with a scintillator of NaI(Tl), photomultiplier and associated electronics laptop to a Dell 630 PC. A data acquisition interface purchased from (Aware Eletronics, USA) provides a file with measurements versus time, in the range from minute to minute recorded in txt. It was observed that the variation of gamma radiation in the interface soil/air at the region is originating from the local radon gas dynamics and of the presence of wind shear near the ground level.