On the scattering of X- and γ- rays by rings of electrons.—The effect of damping of the incident radiation

Abstract

1. The object of the present investigation is to examine whether damping of the incident radiation can account for the abnormally small scattering of hard γ -rays by aluminium, iron and lead, which was observed by Ishino and was left unexplained in a previous investigation, based on the hypothesis that scattering is a phenomenon of the diffraction by electron rings in the atom of undamped simple harmonic wave-trains of high frequency. It may be stated at once that the result of the enquiry is negative: it is true that damping of an amount small enough to be consistent with the generation of moderately sharp lines in the X- and γ -ray spectrum diminishes the scattering of long waves, but it increases that of short waves, and in each case the change is far too small to explain Ishino’s result. On the other hand, very large damping probably diminishes the scattering of all waves, but it is practically certain that it does not diminish it below the amount required by the Simple Pulse theory, whilst Ishino’s values are only of the order of one-quarter of that amount. This result was to be expected, since an infinitely damped wave-train may be regarded as equivalent to a pulse.