April 14. 1932

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[https://cds.cern.ch › record › 1734021 › files › vol47-issue10-p025-e.pdf](https://cds.cern.ch/record/1734021/files/vol47-issue10-p025-e.pdf)

https://cds.cern.ch/record/1734021/files/vol47-issue10-p025-e.pdf

"In April 1932 John Cockcroft and Ernest Walton split the atom
for the first time, at the Cavendish Laboratory in Cambridge in
the UK. Only weeks earlier, James Chadwick, also in Cambridge,
discovered the neutron. That same year, far away in California,
Carl Anderson discovered the positron while working on cosmic
rays. So 1932 was a veritable annus mirabilis in which experi-
ments discovered, and worked with, nucleons; exploited Albert
Einstein’s relativity and energy-mass equivalence principle; took
advantage of the newly emerging quantum mechanics and its
prediction of “tunnelling” through potential barriers; and even
verified the existence of “antimatter” predicted by Paul Dirac’s
relativistic quantum theory of the electron. It is hard to think ofa more significant year in the annals of science..."