GAMMA RAYS INTENSITY VARIATION FROM APRIL TO AUGUST 2018 IN SÃO JOSÉ DOS CAMPOS, BRAZIL REGION

During the period from April 23 to August 29, 2018, the intensity of low energy gamma ray (200 keV to 10.0 MeV) were measured at the ITA campus in the region of São José dos Campos, SP, Brazil. On this occasion between local autumn and winter, there were only one intense rainfallsperiod and some covers of temporally clouds in the region. The gamma ray was monitored each 1 minute intervals and averaged for one day, throughout the net time interval considered in this study. A portable low energy gamma ray scintillator detector was usedmanufactured by Ludlum Enterprises from USA. This system, which consists of a gamma scintillator crystal of (3” x 3”) NaI(Tl) and one photomultiplier with High Tension (HV) andwith data acquisitionsoftware, was tested in the experimental ITA Physics laboratory. The detector show good performance and resolution in detecting gamma photons in the energies released by radioactive sources of Cesium (137Cs) in 662 keV pick and Cobalt (60Co) in 1,17 MeV and 1,33 MeV picks. The dynamics of these intensities of gamma rays was studied during thenet period in this tropical region of Brazil. Maximum value measured in the period comings to 41500 counts/min. and minimum arrives to 37000 counts/min, depending of rain, clouds and local temperatures. Mean value during the day is higher than during night in the region. On dry and hot days, the increase on measured gamma ray intensity was clearly visible, revealing greater exhalation of the radon gas of the region's soil. Discussion on this dynamics of low energy gamma rays and radon gas presence in the region was discussed in this article