Some Observations of Atmospheric Radio-Activity (by the Induction Method)

Abstract

Radio-Active emanations in Atmosphere. 1. The atmosphere contains certain radio-active gases, Radon, Thoron and Actinon (all isotopes of radon) which are occluded from the soil. These emanations arise from the heavy disintegration series of elements, i.e. Uranium-Radium, Thorium and Actinium, which are widely distributed throughout the rocks and soils of the earth's crust. These emanations are:- (i) Radon ₈₆Rn²²² - half life 3.85 days (ii) Thoron ₈₆Rn²²⁰ (Tn) - half life 54.52 secs. (iii) Actinon ₈₆Rn²¹⁹ (An) - half life 3.92 secs. These emanations are chemically inert, heavy gases, each of which disintegrate into a distinct chain of daughter products. Scope of Research. 2. As far as it is known no previous work on atmospheric radio-activity has been carried out in New Zealand. In any case, no estimate of the Radon content, nor ratio of Radon to Thoron in the atmosphere have been published; nor do any investigations into the effect of meteorological conditions on atmospheric radioactivity appear to have been carried out in this area. While the above research, especially that dealing with meteorology, would involve prolonged investigations beyond the scope of a normal thesis, it is considered that some preliminary observations along these lines could make a useful contribution in this field. It is proposed, therefore, to take a series of readings of atmospheric radio-activity with the objects of :- (a) Estimating the average Radon and Thoron content of the atmosphere. (b) Examining the effect of varying meteorological conditions on atmospheric radio-activity.