A New Effect Produced by Action of X-rays on Matter

This paper describes an investigation of the weak radioactivity which some heavier elements acquire after being irradiated by x-rays. The first method of investigation of this effect is based on the measurement of the ionization produced by the sample after irradiation. The second method consists in the counting of the scintillations produced by particles emited by the irradiated substance. The combination of these two methods makes it possible to determine the mean energy of each emitted particle. This energy is of the order of 10^-6 erg. It seems quite impossible that particles of such energy could be emitted from the extranuclear electrons. It is much more probable that they originate in the atomic nuclei. On the other hand it is not possible to explain such results by radioactive contamination. Some possible explanations of the phenomena observed are discussed.