Fission Product Radioactivity in the Air Along the 80th Meridian (West), 1957-1962

摘要

The report summarizes measurements of both gross beta activity and Sr(90) activity in the air at ground level along the 80th meridian during the period 1957 through 1962. More detailed results and interpretations are given for the collections of radioactivity made in 1962. Practically all of the gross beta activity encountered in the air of the Northern Hemisphere during the early part of 1962 and 80-90% of the Sr(90) activity resulted from debris produced in the USSR series of tests held in the fall of 1961. Beginning in the late summer a second large increment of fresh activity, primarily from the USSR tests (AugustDecember 1962), intruded into the air at most of these sites. In the Southern Hemisphere the source of the Sr(90) activity was primarily pre-moratorium bomb debris from a stratospheric source until the initiation of testing by the United States at Christmas Island. From May throughout the remainder of 1962 these tests contributed the bulk of the Sr(90) except in the southernmost areas of Chile, where there was a gradual rise in the contribution of the fresh component. (Author)