Chadwick, James neutron research

Fermi had been fascinated by the discovery of the neutron by James Chadwick in 1932. He gradually switched his research interests to the use of neutrons to produce new types of nuclear reactions, in the hope of discovering new chemical elements or new isotopes of known elements. He had seen at once that the uncharged neutron would not be repelled by the positively-charged atomic nucleus. For that reason the uncharged neutron could penetrate much closer to a nucleus without the need for high-energy particle accelerators. lie discovered that slow neutrons could... 

In 1921, Irene Curie (1897-1956) began research at the Radium Institute. Five years later she married Frederic Joliot (1900-1958). a brilliant young physicist who was also an assistant at the Institute. In 1931, they began a research program in nuclear chemistry that led to several important discoveries and at least one near miss. The Joliot-Curies were the first to demonstrate induced radioactivity. They also discovered the positron, a particle that scientists had been seeking for many years. They narrowly missed finding another, more fundamental particle, the neutron. That honor went to James Chadwick in England. In 1935,... 

In 1932 James Chadwick (1891—1974) bombarded beryllium with alpha particles (helium nuclei) that produced free neutrons. Since then, this nuclear process has made beryhium a reliable neutron emitter for laboratory nuclear research. Beryhium is not only an excellent moderator to slow down high-speed neutrons in nuclear reactors, but it also can act as a... 

M. and Mme. Joliot showed that boron and lithium, when they are bombarded with alpha-rays from polonium, also emit penetrating radiations (126). Their work gave early evidence of the probable existence of the neutron, a hypothesis which has since been fully verified by the researches of Professor James Chadwick, the 1935 Nobel laureate in physics (127). 

Following James Chadwick s discovery of the neutron in 1932, and throughout the decade of the 1930s, the atomic nucleus became the frontier of physical research. And pushing the boundaries of this frontier were many American physicists. 

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