Reprinted in The Physical Review - the First Hundred Years, AIP Press (1995) CD-ROM.
The simple theory of electron capture is outlined and three methods for its detection are suggested. The first experimental evidence for the process (in activated titanium) is described. A rigorous experimental proof of the hypothesis is given for the case of 67Ga. A summary of several isotopes whose properties are best explained on this hypothesis is appended. The properties of 67Ga are described in considerable detail, and include the first evidence for internal conversion
in artificially radioactive atoms.
Related references More (earlier) information appears in L. W. Alvarez, Phys. Rev. 52 (1937) 134;
L. W. Alvarez, Phys. Rev. 53 (1938) 606;
L. W. Alvarez, Phys. Rev. 53 (1938) 326;
L. W. Alvarez, Phys. Rev. 53 (1938) 213;
See also G. E. Uhlenbeck and Kuiper, Physica 4 (1937) 601;
Roberts and N. P. Heydenburg, Phys. Rev. 53 (1938) 374;
Laslett, Phys. Rev. 52 (1937) 529;
W. E. Lamb, Phys. Rev. 50 (1936) 388;
Jacobsen, Nature 139 (1937) 879;
Walke, Phys. Rev. 51 (1937) 1011;
R. C. Williams and E. Pickup, Nature 141 (1938) 199;
Mercier, Nature 139 (1937) 797;
H. Yukawa and S. Sakata, Proc.Phys.Math.Soc.Jap. 18 (1936) 128;
H. Yukawa and S. Sakata, Proc.Phys.Math.Soc.Jap. 17 (1935) 467;
Hoyle, Nature 140 (1937) 235;
67Ga(atom) 67Zn(atom) e
First evidence for the capture of atomic electrons by the weak interaction; K-capture.