Maurice de Broglie (27.04.1875-14.07.1960) was a French physicist and a member of the Paris Academy of Sciences (1924). He was the brother of L. de Broglie. He was born in Paris. He studied (1893 — 95) at the Naval School. He graduated from the University of Marseille (1900). In 1895 — 1908 he was a naval officer; in 1908 he retired and in the same year defended a dissertation at the Collège de France under the supervision of P. Langevin. He carried out his research in his own private laboratory.
His research was in the fields of X-ray spectroscopy, atomic and nuclear physics and the physics of cosmic rays. In 1908 he determined the charge of the electron experimentally, and he replaced the ionisation chamber in the X-ray spectrometer with a photographic plate (the X-ray spectrograph). Independently of W. H. Bragg he proposed the rotating-crystal method and discovered the focusing effect.
A Fellow of the Royal Society and a foreign member of the USSR Academy of Sciences (1927). His pupils include L. de Broglie, L. Leprince-Ringuet, J. Thibaud and others.