Open AccessThe excitation of γ -rays by the α -rays of ionium and radiothorium
Author(s) -
James Chadwick,
A. S. Russell
Publication year - 1913
Publication title -
proceedings of the royal society of london. series a, containing papers of a mathematical and physical character
Language(s) - English
Resource type - Journals
eISSN - 2053-9150
pISSN - 0950-1207
DOI - 10.1098/rspa.1913.0022
Subject(s) - excited state , radium , radiation , physics , gamma ray , roentgen rays , atomic physics , excitation , nuclear physics , radiochemistry , chemistry , quantum mechanics
It has been shown by one of us that theα -rays of radium C, when they impinge upon matter, excite a small but detectable amount ofγ -radiation. Owing to the presence of the intense primaryγ - radiation which accompanies theα -rays of radium C, however, a detailed investigation of this excitedγ -radiation was not possible. With an intense source of ionium placed at our disposal by Prof. Rutherford it has been possible for us, not only to show clearly thatγ -rays are excited by theα -rays of ionium, but also, owing to the absence of products emittingβ andγ -rays, to make a detailed study of the nature of this excitedγ -radiation. The results of these experiments are given in this paper. We have found also thatγ -rays are emitted from radiothorium, and a short account of the work which led to this result is given here also, although, as will be explained later, it was not possible for us to make a systematic study of their nature.