Walther Bothe

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Walther Bothe
University of Heidelberg
Max Planck Institute for Medical Research
Doctoral advisorMax Planck
Signature

Walther Wilhelm Georg Bothe (German pronunciation: [ˈvaltɐ ˈboːtə] ⓘ; 8 January 1891 – 8 February 1957)[2] was a German nuclear physicist know for the development of coincidence methods to study particle physics.

He served in the military during

cosmic rays, and the wave–particle duality of radiation, for which he would receive a share of the Nobel Prize in Physics
in 1954.

In 1930, he became a full professor and director of the physics department at the

Uranverein
(Uranium Club), which was started in 1939 under the supervision of the Army Ordnance Office.

In 1946, in addition to his directorship of the Physics Institute at the KWImf, he was reinstated as a professor at the University of Heidelberg. From 1956 to 1957, he was a member of the Nuclear Physics Working Group in Germany.

In the year after Bothe's death, his Physics Institute at the KWImF was elevated to the status of a new institute under the Max Planck Society and it then became the Max Planck Institute for Nuclear Physics. Its main building was later named Bothe laboratory.

Education

Bothe was born to Friedrich Bothe and Charlotte Hartung. From 1908 to 1912, Bothe studied at the Friedrich-Wilhelms-Universität (today, the Humboldt-Universität zu Berlin). In 1913, he was Max Planck's teaching assistant. He was awarded his doctorate, in 1914, under Planck.[3][4]

Career

Early years

In 1913, Bothe joined the Physikalisch-Technische Reichsanstalt (PTR, Reich Physical and Technical Institute; today, the Physikalisch-Technische Bundesanstalt), where he stayed until 1930. Hans Geiger had been appointed director of the new Laboratory for Radioactivity there in 1912. At the PTR, Bothe was an assistant to Geiger from 1913 to 1920, a scientific member of Geiger's staff from 1920 to 1927, and from 1927 to 1930 he succeeded Geiger as director of the Laboratory for Radioactivity.[3][4][5][6]

In May 1914, Bothe volunteered for service in the German cavalry. He was taken prisoner by the Russians and incarcerated in Russia for five years. While there, he learned the Russian language and worked on theoretical physics problems related to his doctoral studies. He returned to Germany in 1920, with a Russian bride.[5]

On his return from Russia, Bothe continued his employment at the PTR under

Compton effect and the wave–particle duality of light. Bothe's coincidence method and his applications of it earned him the Nobel Prize in Physics in 1954.[6][7][8][9]

In 1925, while still at the PTR, Bothe became a

ausserordentlicher Professor there.[3][4]

In 1927, Bothe began the study of the transmutation of light elements through bombardment with

alpha particles. From a joint investigation with H. Fränz and Heinz Pose in 1928, Bothe and Fränz correlated reaction products of nuclear interactions to nuclear energy levels.[5][6][9]

In 1929, in collaboration with

cosmic rays.[10] The study of cosmic radiation would be conducted by Bothe for the rest of his life.[6][9]

In 1930, he became an

ordentlicher Professor and director of the physics department at the Justus Liebig-Universität Gießen. That year, Bothe and his collaborator Herbert Becker bombarded beryllium, boron, and lithium with alpha particles from polonium and observed a new form of penetrating radiation.[11] In 1932, James Chadwick identified this radiation as the neutron.[3][4][5]

Heidelberg

Walther Bothe

In 1932, Bothe had succeeded

Robert Pohl and Georg Joos, and Arnold Flammersfeld (1939–1941). Also included on his staff were Peter Jensen and Erwin Fünfer.[3][4][5][15][16][17][18]

In 1938, Bothe and Gentner published on the energy dependence of the nuclear photo-effect. This was the first clear evidence that nuclear absorption spectra are accumulative and continuous, an effect known as the dipolar giant nuclear resonance. This was explained theoretically a decade later by physicists J. Hans D. Jensen, Helmut Steinwedel, Peter Jensen, Michael Goldhaber, and Edward Teller.[5]

Also in 1938, Maier-Leibnitz built a Wilson cloud chamber. Images from the cloud chamber were used by Bothe, Gentner, and Maier-Leibnitz to publish, in 1940, the Atlas of Typical Cloud Chamber Images, which became a standard reference for identifying scattered particles.[5][9]

First German cyclotron

By the end of 1937, the rapid successes Bothe and Gentner had with the building and research uses of a

Siemens in September 1938, however, further financing then became problematic. In these times, Gentner continued his research on the nuclear photoeffect, with the aid of the Van de Graaff generator, which had been upgraded to produce energies just under 1 MeV. When his line of research was completed with the 7Li (p, gamma) and the 11B (p, gamma) reactions, and on the nuclear isomer 80Br, Gentner devoted his full effort to the building of the planned cyclotron.[19]

To facilitate the construction of the cyclotron, at the end of 1938 and into 1939, with the help of a fellowship from the Helmholtz-Gesellschaft, Gentner was sent to Radiation Laboratory of the University of California (today, the

Emilio G. Segrè and Donald Cooksey.[19]

After the armistice between France and Germany in the summer of 1940, Bothe and Gentner received orders to inspect the cyclotron

deuterons. Uranium and thorium were irradiated with the beam, and the byproducts were sent to Otto Hahn at the Kaiser-Wilhelm Institut für Chemie (KWIC, Kaiser Wilhelm Institute for Chemistry, today, the Max Planck Institute for Chemistry), in Berlin. In mid-1942, Gentner's successor in Paris, was Wolfgang Riezler [de] from Bonn.[19][20][21]

It was during 1941 that Bothe had acquired all the necessary funding to complete construction of the cyclotron. The magnet was delivered in March 1943, and the first beam of deuteron was emitted in December. The inauguration ceremony for the cyclotron was held on 2 June 1944. While there had been other cyclotrons under construction, Bothe's was the first operational cyclotron in Germany.[4][19]

Uranium Club

The

Heereswaffenamt (HWA, Army Ordnance Office) squeezed out the RFR and took over the effort. Under the control of the HWA, the Uranverein had its first meeting on 16 September. The meeting was organized by Kurt Diebner, advisor to the HWA, and held in Berlin. The invitees included Walther Bothe, Siegfried Flügge, Hans Geiger, Otto Hahn, Paul Harteck, Gerhard Hoffmann, Josef Mattauch, and Georg Stetter. A second meeting was held soon thereafter and included Klaus Clusius, Robert Döpel, Werner Heisenberg, and Carl Friedrich von Weizsäcker. With Bothe being one of the principals, Wolfgang Gentner, Arnold Flammersfeld, Rudolf Fleischmann, Erwin Fünfer, and Peter Jensen were soon drawn into work for the Uranverein. Their research was published in the Kernphysikalische Forschungsberichte
(Research Reports in Nuclear Physics); see below the section Internal Reports.

For the Uranverein, Bothe, and up to 6 members from his staff by 1942, worked on the experimental determination of atomic constants, the energy distribution of fission fragments, and nuclear cross sections. Bothe's erroneous experimental results on the absorption of neutrons in graphite were central in the German decision to favor heavy water as a neutron moderator. His value was too high; one conjecture being that this was due to air between the graphite pieces with the nitrogen having high neutron absorption. However the experimental setup involved a sphere of Siemens electro-graphite submerged in water, no air being present. The error in fast neutron cross-section was due to impurities in the Siemens product: "even the Siemens electro-Graphite contained Barium and Cadmium, both ravenous neutron-absorbers."[22] In any event, there were so few staff or groups that they could not repeat experiments to check results,[23][24][25][26] although in fact a separate group at Gottingen, led by Wilhelm Hanle, determined the cause of Bothe's error: "Hanle's own measurements would show that carbon, properly prepared, would in fact work perfectly well as a moderator, but at a cost of production in industrial quantities ruled prohibitive by [German] Army Ordnance".[27]

By late 1941 it was apparent that the nuclear energy project would not make a decisive contribution to ending the war effort in the near term. HWA control of the Uranverein was relinquished to the RFR in July 1942. The nuclear energy project thereafter maintained its kriegswichtig (important for the war) designation and funding continued from the military. However, the German nuclear power project was then broken down into the following main areas: uranium and heavy water production, uranium isotope separation, and the Uranmaschine (uranium machine, i.e., nuclear reactor). Also, the project was then essentially split up between nine institutes, where the directors dominated the research and set their own research agendas. Bothe's Institut für Physik was one of the nine institutes. The other eight institutes or facilities were: the Institute for Physical Chemistry at the Ludwig Maximilian University of Munich, the HWA Versuchsstelle (testing station) in Gottow, the Kaiser-Wilhelm-Institut für Chemie, the Physical Chemistry Department of the University of Hamburg, the Kaiser-Wilhelm-Institut für Physik, the Second Experimental Physics Institute at the Georg-August University of Göttingen, the Auergesellschaft, and the II. Physikalisches Institut at the University of Vienna.[25][28][29][30]

Post–WW II

From 1946 to 1957, in addition to his position at the KWImF, Bothe was an ordentlicher Professor at the University of Heidelberg.[3][4]

At the end of World War II, the Allies had seized the cyclotron at Heidelberg. In 1949, its control was returned to Bothe.[3]

During 1956 and 1957, Bothe was a member of the Arbeitskreis Kernphysik (Nuclear Physics Working Group) of the Fachkommission II "Forschung und Nachwuchs" (Commission II "Research and Growth") of the Deutschen Atomkommission (DAtK, German Atomic Energy Commission). Other members of the Nuclear Physics Working Group in both 1956 and 1957 were:

Fritz Bopp, Wolfgang Gentner, Otto Haxel, Willibald Jentschke, Heinz Maier-Leibnitz, Josef Mattauch, Wolfgang Riezler [de], Wilhelm Walcher, and Carl Friedrich von Weizsäcker. Wolfgang Paul was also a member of the group during 1957.[30]

At the end of 1957, Gentner was in negotiations with

Kaiser-Wilhelm Gesellschaft), and with the Senate of the MPG to establish a new institute under their auspices. Essentially, Walther Bothe's Institut für Physik at the Max-Planck Institut für medizinische Forschung, in Heidelberg, was to be spun off to become a full fledged institute of the MPG. The decision to proceed was made in May 1958. Gentner was named the director of the Max-Planck Institut für Kernphysik (MPIK, Max Planck Institute for Nuclear Physics) on 1 October, and he also received the position as an ordentlicher Professor at the University of Heidelberg. Bothe had not lived to see the final establishment of the MPIK, as he had died in February of that year.[19][31]

Bothe was a German patriot who did not give excuses for his work with the Uranverein. However, Bothe's impatience with Nazi policies in Germany brought him under suspicion and investigation by the Gestapo.[5]

Personal

As a result of his incarceration in Russia during World War I as a prisoner of war, he met Barbara Below, whom he married in 1920. They had two children. She preceded him in death by some years.[9]

Bothe was an accomplished painter and musician; he played the piano.[9]

Honors

Bothe was awarded a number of honors:[9]

  • Member of the Academy of Sciences of Göttingen
  • Member of the
    Academy of Sciences of Heidelberg
  • Corresponding Member of the
    Saxon Academy of Sciences
    , Leipzig
  • Grand Cross of the Order for Federal Services
  • 1952 – Knight of the Order of Merit for Sciences and the Arts
  • 1953 –
    Deutsche Physikalische Gesellschaft
  • 1954 – Nobel Prize in Physics "for the coincidence method and his discoveries made therewith". Bothe received half of the prize; the other half was awarded to Max Born.
  • 19178 Walterbothe
    , asteroid named after him.

Works

Internal reports

The following reports were published in

Karlsruhe Nuclear Research Center and the American Institute of Physics.[32][33]

Selected literature

  • Walther Bothe and Hans Geiger Ein Weg zur experimentellen Nachprüfung der Theorie von Bohr, Kramers und Slater, Z. Phys. Volume 26, Number 1, 44 (1924)
  • Walther Bothe Theoretische Betrachtungen über den Photoeffekt, Z. Phys. Volume 26, Number 1, 74–84 (1924)
  • Walther Bothe and Hans Geiger Experimentelles zur Theorie von Bohr, Kramers und Slater, Die Naturwissenschaften Volume 13, 440–441 (1925)
  • Walther Bothe and Hans Geiger Über das Wesen des Comptoneffekts: ein experimenteller Beitrag zur Theories der Strahlung, Z. Phys. Volume 32, Number 9, 639–663 (1925)
  • W. Bothe and W. Gentner Herstellung neuer Isotope durch Kernphotoeffekt,
    Die Naturwissenschaften
     Volume 25, Issue 8, 126–126 (1937). Received 9 February 1937. Institutional affiliation: Institut für Physik at the Kaiser-Wilhelm Institut für medizinische Forschung.
  • Walther Bothe The Coincidence Method, The Nobel Prize in Physics 1954, Nobelprize.org (1954)

Books

See also

Notes

  1. ^ "The Nobel Prize in Physics 1954".
  2. ^ Walther Bothe at the Encyclopædia Britannica
  3. ^ a b c d e f g Hentschel, Appendix F; see the entry for Bothe.
  4. ^
    ISBN 0-387-95175-X
    . p. 608
  5. ^ a b c d e f g h Walther Bothe and the Physics Institute: the Early Years of Nuclear Physics, Nobelprize.org.
  6. ^ a b c d Bothe, Walther (1954) The Coincidence Method, The Nobel Prize in Physics 1954, Nobelprize.org.
  7. ^ Hentschel, Appendix F; see the entry for Geiger.
  8. ^ Fick, Dieter and Kant, Horst Walther Bothe's contributions to the understanding of the wave-particle duality of light.
  9. ^ a b c d e f g Walther Bothe Biography, The Nobel Prize in Physics 1954, Nobelprize.org.
  10. ^ Bonolis, Luisa Walther Bothe and Bruno Rossi: The birth and development of coincidence methods in cosmic-ray physics
  11. ^ "The Nobel Prize in Physics 1954". nobelprize.org. Retrieved 23 March 2023. In 1930 Bothe, in collaboration with H. Becker, bombarded beryllium of mass 9 (and also boron and lithium) with alpha rays derived from polonium, and obtained a new form of radiation ...
  12. ^ Beyerchen, pp. 141–167.
  13. ^ Beyerchen, pp. 79–102.
  14. ^ Beyerchen, pp. 103–140.
  15. ^ Hentschel, Appendix F; see the entry of Fleischmann.
  16. ^ Das Physikalische und Radiologische Institut der Universität Heidelberg, Heidelberger Neueste Nachrichten Volume 56 (7 March 1913).
  17. ^ States, David M. (28 June 2001) A History of the Kaiser Wilhelm Institute for Medical Research: 1929–1939: Walther Bothe and the Physics Institute: The Early Years of Nuclear Physics, Nobelprize.org.
  18. ^ Landwehr, Gottfried (2002) Rudolf Fleischmann 1.5.1903 – 3.2.2002, Nachrufe – Auszug aus Jahrbuch pp. 326–328.
  19. ^ a b c d e Ulrich Schmidt-Rohr Wolfgang Gentner: 1906–1980 (Universität Heidelberg).
  20. ^ Jörg Kummer Hermann Dänzer: 1904–1987 (University of Frankfurt).
  21. ISBN 0306810115
    . p. 357.
  22. ISBN 07-5030-6335
    . Retrieved 12 July 2019.
  23. ISBN 0-88736-267-2
    .
  24. ^ Hentschel, pp. 363–364 and Appendix F; see the entries for Diebner and Döpel. See also the entry for the KWIP in Appendix A and the entry for the HWA in Appendix B.
  25. ^
    ISBN 0195070100.{{cite book}}: CS1 maint: location missing publisher (link
    )
  26. ISBN 978-0-387-95086-0
    . pp. 1010–1011.
  27. ISBN 07-5030-6335
    . Retrieved 12 July 2019.
  28. ^ Hentschel, see the entry for the KWIP in Appendix A and the entries for the HWA and the RFR in Appendix B. Also see p. 372 and footnote No. 50 on p. 372.
  29. ^ Walker, pp. 49–53.
  30. ^ a b Kant, Horst (2002) Werner Heisenberg and the German Uranium Project / Otto Hahn and the Declarations of Mainau and Göttingen. Max-Planck Institut für Wissenschaftsgeschichte.
  31. ^ Max Planck Institute for Nuclear Physics, Innovations Report.
  32. ^ Hentschel, Appendix E; see the entry for Kernphysikalische Forschungsberichte.
  33. ^ Walker, 268–274.
  34. ^ Präparat 38, 38-Oxyd, and 38 were the cover names for uranium oxide; see Deutsches Museum.
  35. ^ There were 50-odd volumes of the FIAT Reviews of German Science, which covered the period 1930 to 1946 – cited by Max von Laue in Document 117, Hentschel, 1996, pp. 393–395. FIAT: Field Information Agencies, Technical.

Bibliography

External links

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