Influência de um Colimador Passivo em Medidas de Raio-X na Atmosfera em 11°S de Latitude Geomagnética

Abstract

A comparative analysis of the X-ray measurements, obtained by a passive collimated detector on July 23, 1968 and by an uncollimated detector on April 14, 1981, both using a Nal (Tℓ) scintillation crystal and launched on board balloons from São José dos Campos Brazil (~11°S geomagnetic latitude), is presented. The results show that most of the flux (80%) measured on July 23, 1968 was produced on the collimator (Pb-Sn-Ta, each -1 s-1 at 10g. with a 1 cm thickness), with a production rate of 2.76. 10-2 photons. g cm -2 and for the energy range between 25 and 150 keV. This produced flux, when considered in the calculation of the sensibility of the detector to an additional flux, showed that the collimated detector is less appropriate than the uncollimated one in order to measure any additional flux.