| Popis: |
The ionization produced by the alpha rays of radon, thoron, and their successive products in the atmosphere was measured in the garden of the Seismic Station of Fordham University from October 1949 to July 1950. The results of the observations in November and December have been published previously by Hess and Vancour . On account of an error which was overlooked at that time the whole series of observations had to be recomputed, including the unpublished results of 1950. Samples of air from outdoors were filled into a large ionization chamber which was evacuated previously and was standing in an iron house with walls thick enough to shield off local gamma rays. The background was so low that it was possible to measure the ionization by alpha rays of the products filled into the chamber and to follow up its diminution for several days. It was found that the average radon content amounted to 54 × 10 −18 curies per cm 3 . The total average ionization produced by the alpha rays from radon and its decay products was about 0.70 I while thoron and its decay products give 0.54 I , or about 44% of the total ionization due to alpha rays. |
