Sir Francis Simon (2 July 1893 – 31 October 1956), was a German and later British physical chemist and physicist who devised the

gaseous diffusion Gaseous diffusion is a technology used to produce enriched uranium by forcing gaseous uranium hexafluoride (UF6) through semipermeable membranes. This produces a slight separation between the molecules containing uranium-235 (235U) and uranium-2 ...

method, and confirmed its feasibility, of separating the isotope

Uranium-235 Uranium-235 (235U or U-235) is an Isotopes of uranium, isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile ...

and thus made a major contribution to the creation of the

atomic bomb A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bomb ...

Early life

Born Franz Eugen Simon to a Jewish family in

Berlin Berlin is Capital of Germany, the capital and largest city of Germany, both by area and List of cities in Germany by population, by population. Its more than 3.85 million inhabitants make it the European Union's List of cities in the European U ...

, Franz was the son of Ernst Simon and Anna Mendelssohn, daughter of the mathematician Philibert Mendelssohn. Two of his cousins, Kurt Mendelssohn and

Heinrich Mendelssohn Heinrich Mendelssohn (21 February 1881 – 7 August 1959) was a German contractor and real estate developer. Early life Mendelssohn was born in Posen, German Empire( today Poznań, Poland) in 1881. A claimed connection to the family of the fa ...

, were also scientists. He won the

Iron Cross The Iron Cross (german: link=no, Eisernes Kreuz, , abbreviated EK) was a military decoration in the Kingdom of Prussia, and later in the German Empire (1871–1918) and Nazi Germany (1933–1945). King Frederick William III of Prussia e ...

First Class during

World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was List of wars and anthropogenic disasters by death toll, one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, ...

. He received his doctoral degree from the

University of Berlin The Humboldt University of Berlin (german: link=no, Humboldt-Universität zu Berlin, abbreviated HU Berlin) is a public research university in the central borough of Mitte in Berlin, Germany. The university was established by Frederick Will ...

, working in the research group of Walther Nernst on low-temperature physics related to the Nernst Heat Theorem (

Third law of thermodynamics The third law of thermodynamics states, regarding the properties of closed systems in thermodynamic equilibrium: This constant value cannot depend on any other parameters characterizing the closed system, such as pressure or applied magnetic fiel ...

). In 1931 he was appointed Professor of Physical Chemistry at the

University of Breslau A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. ''University'' is derived from the Latin phrase ''universitas magistrorum et scholarium'', which ...

Emigration

The rise of anti-Semitic fascism in Germany in the 1930s caused him and his wife to consider emigrating. Aware of his concerns

Frederick Lindemann, 1st Viscount Cherwell Frederick Alexander Lindemann, 1st Viscount Cherwell, ( ; 5 April 18863 July 1957) was a British physicist who was prime scientific adviser to Winston Churchill in World War II. Lindemann was a brilliant intellectual, who cut through bureau ...

met him in Walther Nernst's laboratory during Easter 1933, and invited him to join the Clarendon Laboratory at the

University of Oxford The University of Oxford is a collegiate research university in Oxford, England. There is evidence of teaching as early as 1096, making it the oldest university in the English-speaking world and the world's second-oldest university in contin ...

. He was also able to offer him a two-year grant research from

Imperial Chemical Industries Imperial Chemical Industries (ICI) was a British chemical company. It was, for much of its history, the largest manufacturer in Britain. It was formed by the merger of four leading British chemical companies in 1926. Its headquarters were at M ...

(ICI) of £800. Simon resigned on 1 July 1933, but before he could leave an official demanded that he and his wife surrender their passports. Simon then flung his Iron Cross and other medals onto the table. Their passports were later returned, for reasons unknown. Using the services of a corrupt customs official Simon was able to take his research equipment with him. His wife and children followed him two months later. Upon arrival in the UK, he started using the

Anglicised Anglicisation is the process by which a place or person becomes influenced by English culture or British culture, or a process of cultural and/or linguistic change in which something non-English becomes English. It can also refer to the influen ...

name "Francis".

Work in England

Using the equipment he had brought with him from Germany he performed pioneering work in low temperature physics. In 1936 he was able to produce the first liquid

helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...

by using magnetic cooling at a laboratory at Bellevue near Paris. His ICI grant was extended to 1938 which allowed him to turn down an offer of a 10-year contract as Professor of Physical Chemistry at Istanbul. In 1936 despite being supported by

Einstein Albert Einstein ( ; ; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist, widely acknowledged to be one of the greatest and most influential physicists of all time. Einstein is best known for developing the theory ...

, Nernst, Planck and Rutherford he was unsuccessful in beating

Mark Oliphant Sir Marcus Laurence Elwin Oliphant, (8 October 1901 – 14 July 2000) was an Australian physicist and humanitarian who played an important role in the first experimental demonstration of nuclear fusion and in the development of nuclear weapon ...

for the Chair of Physics at

Birmingham University The University of Birmingham (informally Birmingham University) is a Public university, public research university located in Edgbaston, Birmingham, United Kingdom. It received its royal charter in 1900 as a successor to Queen's College, Birmingha ...

. His job security in Oxford improved in 1936 when he was appointed Reader in

Thermodynamics Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws o ...

and a Student of Christ Church. Because he was naturalised, until 1940 he was prevented from working on

radar Radar is a detection system that uses radio waves to determine the distance ('' ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...

. Because he was also on the list of people targeted for retribution by the Nazis his wife and children took up an offer to spend the war in Canada. Simon remained behind in Oxford. In 1940 in collaboration with

Nicholas Kurti Nicholas Kurti, ( hu, Kürti Miklós) (14 May 1908 – 24 November 1998) was a Hungarian-born British physicist who lived in Oxford, UK, for most of his life. Career Born in Budapest, Kurti went to high school at the Minta Gymnasium, but due ...

and Heinrich Gerhard Kuhn, he was commissioned by the

MAUD Committee The MAUD Committee was a British scientific working group formed during the Second World War. It was established to perform the research required to determine if an atomic bomb was feasible. The name MAUD came from a strange line in a telegram fro ...

to investigate the feasibility of separating uranium-235 by

. He initially adapted his wife's wire kitchen strainer to assist in this work before commissioning a membrane from ICI containing 160,000 holes to the square inch. His resulting conclusions on the separation of uranium isotopes was transferred to the

Manhattan Project The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project w ...

and was the basis of the process that produced sufficient U235 to make the atomic bomb. He spent the latter part of the Second World War at Los Alamos, returning in 1945 to Oxford to continue his low temperature research. He became a professor at the

and a Student of Christ Church, Oxford in 1945. Upon the retirement of Lord Cherwell he became Dr Lee's Professor of Experimental Philosophy and head of the Clarendon Laboratory in 1956, one month before his death from coronary disease.

Personal life

He married Charlotte Münchhausen in 1922. They had two daughters, Kathrin and Dorothee.Medawar & Pyke. Page 80.

Honours

* Fellow of the

Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, r ...

, 1941 * CBE, 1946 *

Rumford Medal The Rumford Medal is an award bestowed by Britain's Royal Society every alternating year for "an outstandingly important recent discovery in the field of thermal or optical properties of matter made by a scientist working in Europe". First awar ...

of the Royal Society, 1948 * Knighted, 1954

References

Bibliography

External links

Annotated bibliography for Francis Simon from the Alsos Digital Library for Nuclear Issues

Weintraub, B. Francis Simon. The Israel Chemist and Chemical Engineer, August 2018.
{{DEFAULTSORT:Simon, Francis 1893 births 1956 deaths Jewish emigrants from Nazi Germany to the United Kingdom Fellows of the Royal Society Fellows of Christ Church, Oxford Jewish scientists Knights Bachelor Commanders of the Order of the British Empire 20th-century British physicists 20th-century German physicists Recipients of the Iron Cross (1914), 1st class Dr Lee's Professors of Experimental Philosophy Jewish physicists Members of the American Academy of Arts and Letters Fellows of the American Physical Society