A hypothesis as to the origin of cosmic rays and its experimental testing in India and elsewhere
The hypothesis here adopted as to the mode of origin of the cosmic rays makes possible the prediction of five definite cosmic-ray bands, each of which should reach the earth in a particular latitude, and of four plateaus of unchanging cosmic-ray intensity, these plateaus being delimited by the latitudes of entrance of the successive bands. These bands will be designated as (1) a silicon band of energy 13.2 Bev, (2) an oxygen-nitrogen band of mean energy 7.1 Bev, (3) a carbon band of energy 5.6 Bev, and (4) a helium band of energy 1.9 Bev. The experimental evidence that has been so far obtained in India and elsewhere for the existence of these five bands and four plateaus may be thus summarized: The evidence seems to be excellent for the existence of the silicon band and the joint nitrogen-oxygen band, and some indications have appeared for the existence of the carbon band and the helium band. Also all of these bands are found, roughly at least, in the predicted latitudes and of right order of intensities. The evidence also appears to be good for the existence of at least three of the four above-mentioned plateaus of constant cosmic-ray intensity.
©1942 The American Physical Society. Received 9 February 1942. This comparison of prediction and experiment has been made possible largely through the generous support of the investigation by the Carnegie Corporation of New York and the Carnegie Institution of Washington. The success of the work in India was made possible by the extraordinarily generous and complete cooperation of the British Indian Meteorological Service.