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The Sudbury Neutrino Observatory experiment


Looking forward to the Sudbury Neutrino Observatory experiment
Hans Bethe Scientist
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We are looking forward to another experiment which has been in preparation for several years. The experiment is taking place in an abandoned... not not abandoned, in an old nickel mine in Sudbury, Ontario, which is quite far north and is known as the Subdury Neutrino Observatory, SNO - sno, and there's lots of snow in Sudbury of course. The... this experiment uses heavy water, and the deuteron is a lovely particle which I have been dealing with in all my scientific life, in this case it can respond to a neutrino in two ways. It can either disintegrate directly into a neutron plus a proton, or it can disintegrate into two protons... and an electron. In the latter case you can see the electron with has a high energy if the neutrino has a high energy, and... I should say that only... again, only the boron neutrinos are observable in the SNO experiment. So you either get a high energy electron, or you get a neutron from the neutral reaction making a neutron plus a proton. The neutron in turn you can observe in two different ways. The way I like best is to have in the... embedded in the heavy water a counter of helium-3, a neutron and a helium-3 give you hydrogen-3 plus a proton of... and you can observe that fairly easily. It has an enormous cross section. So... then there is another way to observe the neutron, but let me not go into that.

The late German-American physicist Hans Bethe once described himself as the H-bomb's midwife. He left Nazi Germany in 1933, after which he helped develop the first atomic bomb, won the Nobel Prize in Physics in 1967 for his contribution to the theory of nuclear reactions, advocated tighter controls over nuclear weapons and campaigned vigorously for the peaceful use of nuclear energy.

Listeners: Sam Schweber

Silvan Sam Schweber is the Koret Professor of the History of Ideas and Professor of Physics at Brandeis University, and a Faculty Associate in the Department of the History of Science at Harvard University. He is the author of a history of the development of quantum electro mechanics, "QED and the men who made it", and has recently completed a biography of Hans Bethe and the history of nuclear weapons development, "In the Shadow of the Bomb: Oppenheimer, Bethe, and the Moral Responsibility of the Scientist" (Princeton University Press, 2000).

Tags: Sudbury, Ontario, Sudbury Neutrino Observatory, Creighton Mine

Duration: 2 minutes, 57 seconds

Date story recorded: December 1996

Date story went live: 24 January 2008