Ernest Walton; Won Nobel in Physics for Splitting Atom
Nobel laureate Ernest Walton, who helped usher in the nuclear age when in 1932 he and John Cockcroft split an atom, has died at age 91.
Walton died Sunday at Belfast City Hospital.
He and Cockcroft, an Englishman who died in 1967, were awarded the 1951 Nobel Prize in physics in belated recognition of their atom-splitting breakthrough 19 years earlier at Cambridge University’s Cavendish Laboratory.
The son of a Methodist minister, Walton was born in Dungarvan, 100 miles southwest of Dublin. In 1922 he entered Trinity College, Dublin, to study physics and mathematics.
He arrived in England in 1929 on a research scholarship at the Cavendish Laboratory, which was under the direction of Ernest Rutherford. A pioneer of atomic physics, Nobel laureate Rutherford, a New Zealander, had been the first to recognize the nuclear nature of the atom.
Walton was interested in beaming particles into the nuclei of atoms, which up to then had proved impossible because of the large amount of electricity needed.
Rutherford teamed Cockcroft and Walton who, with little cash, used bicycle parts, modeling clay, cookie tins, sugar crates and glass tubes from old gasoline pumps to build what became the prototype of nuclear accelerators.
They took over an unused lecture hall, ripping out the seats to accommodate their atom-splitter. A packing crate with scraps of lead nailed to it protected them from X-rays and electrocution.
When Walton switched the apparatus on, it sent an electrical charge blasting down a glass tube. A screen under a microscope monitored the debris that flew from a stamp-sized piece of lithium when the beam hit.
“Particles were coming out of the lithium, hitting the screen and producing scintillations. They looked like stars suddenly appearing and disappearing,” he said.
The “stars” were alpha particles from disintegrating atoms. The Nobel citation spoke of “pioneering work on the transmutation of atomic nuclei by artificially accelerated particles.”
In a science paper in 1945, “Unlocking Atomic Energy,” Walton said he hoped that if an enlightened human race did not prevent the use of atomic discoveries in war, a frightened one would.
Walton returned to Dublin in the early 1930s, refusing offers of employment in the United States. He continued his work on atoms as a professor of natural and experimental philosophy at Trinity College.
