Walther Bothe
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Walther Bothe  |
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 Walther Bothe
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| Born | January 8, 1891 Oranienburg, Germany |
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| Died | February 8, 1957 Heidelberg, Germany |
| Residence |  Germany |
| Nationality | German |
| Fields | Physicist, mathematician, chemist |
| Institutions | University of Berlin University of Giessen Ruprecht-Karls-Universität Heidelberg |
| Alma mater | University of Berlin |
| Doctoral advisor | Max Planck |
| Doctoral students | Hans Ritter von Baeyer |
| Known for | Coincidence circuit |
| Notable awards | Nobel Prize for Physics (1954) |
Walther Wilhelm Georg Bothe (January 8, 1891 – February 8, 1957) was a German physicist, mathematician, chemist, and Nobel Prize laureate who with Max Born invented the coincidence circuit.
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[edit] Biography
[edit] Early years
Bothe was born in Oranienburg, Germany (near Berlin) and studied physics from 1908 until 1912 at the University of Berlin under Max Planck, earning his doctorate by 1914. During World War I he was taken prisoner by the Russians and spent a year in captivity in Siberia.[1]
After the war, he collaborated with Hans Geiger at Physikalisch-Technische Reichsanstalt in Berlin, where he made his most important discoveries. He discovered that if a single particle is detected by two or more Geiger counters, the detection will be practically coincident in time. Using this observation, he constructed the coincidence circuit allowing several counters in coincidence to determine the angular momentum of a particle. Bothe's coincidence circuit was one of the first AND logic gates (1924). Bothe studied the Compton effect using such a set up, thus establishing the modern analysis of scatter processes.
[edit] Middle years
During the 1920s, Bothe used the coincidence method to discover penetrating radiation coming from the upper atmosphere; this radiation is now known as cosmic rays. His data indicated that the radiation was not composed exclusively of gamma rays, but was also composed of high energy particles (now known to be mostly mesons).
Bothe began applying the coincidence method to the transmutation of light elements by the bombardment with alpha particles in 1927. In the 1930s, he found that the radiation emitted by beryllium when it is bombarded with alpha particles was a new form of penetrating high energy radiation, which was later shown by James Chadwick to be neutrons.
Bothe taught at the University of Berlin from 1920 to 1931, at the University of Giessen from 1931 to 1934[2] and in 1932 was appointed Director of the Institute of Physics at the University of Heidelberg, succeeding Philipp Lenard. He also began working at the Kaiser Wilhelm Institute (now the Max Planck Institute) at this time. In 1934, Bothe became Director of the Institute of Physics at the Max Planck Institute for Medical Research. In 1938, Wolfgang Gentner and Bothe published a paper on the energy dependence of the nuclear photo-effect, which was the first decisive evidence that the absorption spectra of nuclei are accumulative and continuous.
[edit] Later years and death
In 1941, Bothe and Peter Jensen reported the results of testing on neutron absorption in graphite. However, their erroneous conclusions contributed to stifling the German nuclear program in World War II. In 1943, Bothe completed Germany's first cyclotron, and was awarded the Max Planck medal in 1953. Bothe continued to work at the Institute of Physics in the Max Planck Institute until his death in Heidelberg in 1957.
[edit] Personal life
Bothe considered himself a German patriot, and did not believe that his German weapons research during the Second World War required an excuse.
Bothe married Barbara Belowa of Moscow and had two children. He was interested in music (playing the piano) and painting (oil painting and water color). Bothe was sensitive to criticism and kept problems privately.
[edit] Publications
- Bothe, W. and Hans Geiger, "Experimentaler Teil". 1921.
- Bothe, W., "Bemerkung yur vorstehenden Arbeit". 1921.
- Bothe, W., "Remarks on the Leipziger DÒ attempt". 1941.
- Bothe, W., "The distribution of velocity of the neutrons in a braking means". 1942.
- Bothe, W., "The vermehrung of fast neutrons in uranium and some other work from the KWI Heidelberg".
- Bothe, W., "Over radiation protection walls".
- Bothe, W. and W. Fuenfer, "Layer attempts with variation of the u and DÒ thicknesses".
[edit] See also
- Electronics: Logic gate, Geiger counter, Timeline of computing, Coincidence circuit
- List of physics topics: Robert S. Mulliken, Neutron, Nobel Prize in Physics, Compton effect
- Other: Tractatus Logico-Philosophicus (5.101)
[edit] References
- ^ From Nobel Lectures, Physics 1942-1962, Elsevier Publishing Company, Amsterdam, 1964
- ^ Guide to the Nobel Prizes
[edit] External links and further reading
- States, David M., "Walther Bothe and the Physics Institute: The Early Years of Nuclear Physics". History of the Kaiser Wilhelm Institute (now the Max Planck Institute) for Medical Research
- "Walther Bothe". The Nobel Foundation, 2004.
- "Walther Bothe and the Physics Institute: the Early Years of Nuclear Physics". The Nobel Foundation.
- "Walther Wilhelm Georg Bothe". Nobel-winners.com.
- Bethe, Hans, "The German Uranium Project, Creating Copenhagen". City University of New York, 2000.
- Annotated bibliography for Walther Bothe from the Alsos Digital Library for Nuclear Issues
- Hoffmann, Dieter, Horst Kant and Hubert Laitko. "Walther Bothe - Wissenschaftler in vier Reichen. Forschungsschwerpunkt für Wissenschaftsgeschichte und Wissenschaftstheorie". 1995. (tr. "Walther Bothe - scientists in four realms. Main point of research for science history and science theory")
