Open AccessThe passage of cathode rays through matter
Publication year - 1923
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.1923.0105
Subject(s) - exponential function , cathode , constant (computer programming) , beam (structure) , exponential decay , physics , intensity (physics) , fraction (chemistry) , nuclear physics , computational physics , optics , mathematics , mathematical analysis , chemistry , computer science , programming language , organic chemistry
The pioneer experiments of Lenard on the passage of cathode rays through matter led him to the well-known exponential law of absorptiom I/I0 ═ e-λt , (1) where I0 is the incident, I the emergent, intensity of the beam,t the thickness of the absorbing material, andλ a constant depending upon the density of the material and the velocity of the rays. These experiments were followed up by Becker and Leithauser whose results agreed with the exponential relation, provided that I0 was corrected for the reflected fraction of the beam. The values ofλ obtained by these three observers are not, however, in even approximate agreement, and owing to the slow speed of the rays employed and to experimental difficulties, their results do not appear to provide sufficient evidence for the truth of equation (1).