Artificial Radioactivity Produced by the Deuteron Bombardment of Nitrogen

This paper describes the work leading to the discovery and investigation of radio-oxygen, and also includes some incidental results on other nuclear disintegrations. It is shown that nitrogen bombarded with deuterons gives rise to a radioactive substance which emits positive electrons of maximum energy 1.2 mv, has a half-life of 126±{}5 sec., and is found by chemical analysis to be an isotope of oxygen. The nuclear cross section for the activation of nitrogen at 2 mv deuteron energy is 6×{}10^-27 cm²; that for the activation of carbon is three times as great. The neutrons expected to accompany the formation of radio-oxygen were found to be present. These results were obtained using gaseous nitrogen as a target; in some of the experiments use was made of the fact that the active product can be deposited on a metal surface by recoil.