Stratified regions of high radioactivity in the atmosphere over Hyderabad, India, in April, 1968

Abstract

In a balloon flight from Hyderabad, India on 28th April, 1968 with an X-ray telescope recording X-rays in the energy band 16-125 KeV, two stratified layers of high radioactivity in the atmosphere were observed at an altitude of 16-20 km. The excess radiation was concentrated in the layers located at 16.4-17.2 km and 18.6-20.1 km separated by a region of normal counting rate. The two distinct layers of excess radiation were recorded in all the six different energy channels and the energy spectrum of the excess radiation was measured. A subsequent balloon flight from the same location with the same instrument on December 22, 1968 did not show any excess radioactivity in the atmosphere. It is concluded that the excess atmospheric radioactivity on April 28, 1968 origimated from the global fallout from the nuclear detonation, presumably from the air burst by China on June 17, 1967. The interesting aspect of the present observations is the occurrence of stratified layers of activity in the tropopause region near equator several months after the explosion.