Hans von Halban (physicist)

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Hans H. von Halban jun. 1942 in Montreal

Hans Heinrich von Halban (also Hans H. von Halban junior , born January 24, 1908 in Leipzig , † November 28, 1964 in Paris ) was a French nuclear physicist from the Halban family . He made significant contributions to research into nuclear fission .


After completing school in Würzburg, he began studying physics in Frankfurt / Main. His father , Hans von Halban Sr. had for a time lecturer at Julius Tafel 1924, the management of the metallurgical laboratory of Metallgesellschaft in Frankfurt a. M. taken over. In the 1930/31 winter semester, his father succeeded Victor Henri at the University of Zurich and Hans von Halban jun. did his doctorate there in December 1934 with E. Meyer with a thesis on " vapor pressure abnormalities in capillary-active amalgams ". He then worked for several years with the Austrian Otto Frisch in Copenhagen and in 1938 accepted Frédéric Joliot-Curie's invitation to the Collège de France in Paris to research moderation problems with uranium decay.

After the German occupation of France , von Halban fled to Great Britain with Lew Kowarski . In London , at the invitation of Winston Churchill, he continued his nuclear physics research at Cambridge University. In 1942 he was sent to Montreal as laboratory manager . There he was involved in the Manhattan project .

After the end of the war in 1945 he visited Paris and met Joliot-Curie, but after his return from Europe he was relieved of his duties as laboratory manager. Halbans was succeeded by John Cockcroft and, as a hijackable carrier of current knowledge, was not allowed to leave North America or work there for a year. Espionage activities by the USSR threatened the security of the American nuclear weapons program around the world. After that he received no further invitations from the Collège de France. Instead, through the mediation of Frederick Lindemann in Great Britain, he became head of the Clarendon Laboratory at Oxford University , which had close ties to the Harwell Nuclear Research Center .

In 1955 he accepted an invitation from the French Prime Minister Pierre Mendès France . He built a linear accelerator in Orsay , near the Saclay research center of the CEA . He managed this facility until 1961, when he took early retirement for health reasons.

Von Halban was married three times and had three children from his first and second marriage. He spent the last three years of his life in Paris and in Crans-sur-Sierre . He died as a result of heart surgery and was buried in Larchant .


Broompark freighter 1940

In Copenhagen, discovered by Halban together with Otto Frisch that heavy water D 2 O compared to ordinary water H 2 O a very low absorption cross section has for neutrons. In Paris, together with Kowarski and Joliot-Curie, he measured the average number of neutrons released in a nuclear fission.

For his escape to Great Britain he received a special order from the French Army Minister Raoul Dautry to ensure that the heavy water and uranium of the group around Joliot-Curie would not end up in German hands. Shortly before, France had acquired 185 kg of heavy water from Norsk Hydro for Joliot-Curie , which corresponded to a large part of the world’s supplies at the time. He first transported it in the trunk of his car to Bordeaux and from there with the coal freighter "Broompark" near the coast. From here the canisters were taken to Great Britain on a British submarine.

In 1949, the “Comptes Rendus” published a paper that Halban, Joliot-Curie and Kowarski had handed over to the French Academy of Sciences in October 1939 in a sealed envelope that was only opened after the war. This paper, entitled “Sur la possibilité de produire dans un milieu uranifère des réactions nucléaires en chaine illimitée” (German “On the possibility of triggering a nuclear chain reaction with the help of uranium” ) contained the theoretical foundations for the military and civil use of the Nuclear energy.

In 2007 the Royal Society announced that it had opened five sealed envelopes containing research by von Halban and Kowarski. These work results had been given to the Royal Society in 1940 by James Chadwick with the request not to publish them. They contained methods of producing plutonium from uranium and stabilizing nuclear chain reactions.

Individual evidence

  1. Klaus Koschel and Gerhard Sauer, On the history of the Chemical Institute of the University of Würzburg, pp. 66–71, self-published by the university in 1968.
  2. ^ Obituary of Hans v. Halban Sr. (1877-1947) by M. Kofler, Helvetica Chimica Acta 31 , 120-128 (1948), doi : 10.1002 / hlca.19480310127 .
  3. Physically. Chemistry University of Zurich ( Memento of the original from January 2, 2014 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  @1@ 2Template: Webachiv / IABot / www.unipublic.uzh.ch
  4. Dissertation December 18, 1934, Hans H. von Halban jun. in Helvetica Physica Acta. 8 , 65-81 (1935)
  5. Danish publications Hans von Halban jun. and Otto Frisch in 1937 and 1938
  6. ^ Picture from 1939 in Paris
  7. Nigel West: Mortal Crimes - The Greatest Theft in History: The Soviet Penetration of the Manhattan Project, Chapter I.
  8. H. von Halban, F. Joliot and L. Kowarski, Nature 143 , 470 , 680 and 939 (1939).
  9. ^ Youtube video Paris 1939 (4-6 min: Joliot-Curie, von Halban and Kowarski ) and military sabotage operations in Norway
  10. British freighter Broompark
  11. H. von Halban, F. Joliot and L. Kowarski, Comptes Rendus 229 (1949) 909.
  12. BBC on the discovery of research by Kowarski and von Halban


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