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×${10}^{-27\mathrm{}}$ ${\mathrm{cm}}^2$; 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.

• Received 21 January 1935

DOI:https://doi.org/10.1103/PhysRev.47.452