{"id":3183,"date":"2024-03-20T01:42:11","date_gmt":"2024-03-20T01:42:11","guid":{"rendered":"https:\/\/wp.ccnr.org\/?page_id=3183"},"modified":"2024-03-27T04:32:20","modified_gmt":"2024-03-27T04:32:20","slug":"canadas-role-in-the-atomic-bomb-programs-of-the-united-states-britain-france-and-india","status":"publish","type":"page","link":"https:\/\/wp.ccnr.org\/fr\/canadas-role-in-the-atomic-bomb-programs-of-the-united-states-britain-france-and-india\/","title":{"rendered":"Canada’s Role in the Atomic Bomb Programs of the United States, Britain, France and India"},"content":{"rendered":"
\n

Canada’s Role
\nin the Atomic Bomb Programs
\nof the United States, Britain, France and India<\/span><\/h2>\n

 <\/p>\n

~ A Chronology ~<\/span><\/h2>\n

 <\/p>\n

by Gordon Edwards, Ph.D.<\/h6>\n
\n

Christmas 1938:<\/span><\/big><\/b><\/p>\n

In Berlin, Hahn and Strassman discover that the nucleus of a uranium atom can be ”split” or ”fissioned” by bombarding it with neutrons.<\/span><\/b><\/p>\n

January 1939:<\/span><\/big><\/b><\/p>\n

Lise Meitner, a German emigr\u00e9e, working with Neils Bohr in Norway, provides the theoretical framework for understanding how nuclear fission occurs.<\/span><\/b><\/p>\n

<\/a>February 1939:<\/span><\/big><\/b><\/p>\n

A group of scientists in Paris — Fr\u00e9deric Joliot, Hans van Halban, Lew Kowarski and Francis Perrin — show that when a uranium nucleus fissions, two or three extra neutrons are also given off. This important observation suggests that a self-sustaining chain reaction might be possible.<\/span><\/b><\/p>\n

It is immediately apparent to scientists everywhere that, in principle, an extremely powerful explosive could be created — an ”atomic bomb” — but for years, many scientists continue to think of it as a practical impossibility.<\/span><\/b><\/p>\n

May 1939:<\/span><\/big><\/b><\/p>\n

Francis Perrin of the Paris Group (mentioned above) defines a ”critical mass” of uranium to be the smallest amount needed to sustain a chain reaction.<\/span><\/b><\/p>\n

The Paris Group recognizes that natural uranium cannot sustain a chain reaction without a ”moderator” — something to slow down the fast-moving neutrons given off by the fissioning uranium atoms, so that more fissions can take place more easily.<\/span><\/b><\/p>\n

(This is due to the presence of uranium-238, which does not fission as readily as uranium-235; in fact uranium-238 atoms actually absorb many neutrons that would have helped to keep the fissioning of uranium-235 atoms going.)<\/span><\/b><\/p>\n

January – April 1940 : FRANCE<\/span><\/big><\/b><\/p>\n

Early in 1940 the Paris group decides on theoretical grounds that ”heavy water” would be an ideal moderator. They ask the French Minister of Armaments to obtain as much heavy water as possible. The only place it is being made is at a large hydroelectric station in Norway.<\/span><\/b><\/p>\n

The French discover that the Germans have already offered to purchase the entire stock of Norwegian heavy water — a frightening indication that Germany too might be pursuing research on an atomic bomb.<\/span><\/b><\/p>\n

Once the Norwegian Government learns of the possible military significance of heavy water, they entrust it all to a French Secret Service man who smuggles it into France via England just before Germany invades Norway in April 1940.<\/span><\/b><\/p>\n

A \u00a0 bomb-proof shelter \u00a0 is built near Paris to house the precious liquid.<\/span><\/b><\/p>\n

January-April 1940 : BRITAIN<\/span><\/big><\/b><\/p>\n

Unlike the French, the British focus on the possibility of an atomic bomb using fast (unmoderated) neutrons. After a brief flirtation with the idea, they conclude that an atomic bomb using uranium is impossible with fast neutrons, because too many neutrons get lost or captured by the uranium-238 atoms.<\/span><\/b><\/p>\n

Then in March, 1940, Otto Frisch and Fritz Peierls — two refugee German scientists living in England — hit upon a startling new idea. On three typewritten pages, they outline how an atomic bomb can be built and detonated using only a few kilograms of uranium-235, the lighter isotope of uranium, fissioned wholly by fast neutrons.<\/span><\/b><\/p>\n

Frisch and Peierls observe that if uranium-235 is completely separated from uranium-238, there is no need to slow the neutrons down. No moderator is required.<\/span><\/b><\/p>\n

In the same three-page paper, they warn<\/span><\/b><\/p>\n