Atmospheric X-rays at 110S geomagnetic latitude

X-ray measurements at balloon altitudes were made at Sao Jose dos Campos, Brasil (23012'S,45051'W geographic coordinates, approx. 110S geomagnetic latitude) on 18 December 1981, using an omnidirectional NaI(Tl) scintillation detector. Atmospheric X-rays, namely secondary X-radiation from cosmic rays, were measured for the energy interval 30-155 keV and up to an atmospheric depth of 5.5 g cm-2. A comparison of the flux measured at the Pfotzer maximum during these measurements with those obtained previously by several research groups at other latitudes and with a similar technique has also been made. A comparison of the atmospheric component with that attributed to the diffuse component is also presented and it is concluded that both components are of about the same magnitude at approx. 5 g cm-2 and at approx. 110S geomagnetic latitude. (author)