Publisher Information: 1934.
Szilard, Leo (1898-1964) and Thomas A. Chalmers. Detection of neutrons liberated from beryllium by gamma rays: A new technique for inducing radioactivity. Offprint from Nature 134 (1934). Single sheet, unbound. pp. 216 x 134 mm. Crease in upper left corner, lower right corner chipped, light toning but very good. Presentation Copy, inscribed in the upper right corner in an unidentified hand: “With compliments of L. Szilard.”
First Edition, Offprint Issue. In 1933, after fleeing from Germany to England to escape the Nazis, Hungarian theoretical physicist Leo Szilard came up with the idea of the nuclear chain reaction while crossing a street in London. He filed his first patent on the chain reaction in March 12, 1934 and that summer, in collaboration with T. A. Chalmers, he began a series of experiments on the beryllium nucleus using radium owned by the physics department at St. Bartholomew’s Hospital Medical College.
"The beryllium nucleus was so lightly bound [Szilard] suspected he could knock neutrons out of it not only with alpha particles or neutrons but even with gamma rays or high-energy X rays . . . Their first experiment demonstrated a brilliantly simple method for separating isotopes of iodine by bombarding an iodine compound with neutrons. They then used this Szilard-Chalmers effect (as it came to be called), which was extremely sensitive, as a tool for measuring the production of neutrons in their second experiment: knocking neutrons out of beryllium using the gamma radiation from radium" (Rhodes, The Making of the Atomic Bomb, p. 215).
The results of this second experiment are described in the present offprint. To Szilard’s disappointment, beryllium proved to be an unsuitable candidate for chain reaction; it was not until 1939, after the discovery of nuclear fission, that Szilard and Enrico Fermi were able to produce a nuclear chain reaction in uranium. The first self-sustaining nuclear chain reaction—which made possible the atomic bomb—was accomplished by Fermi and his associates in 1942.Book Id: 43260