He served in the military duringWorld War I from 1914, and he was a prisoner of war of the Russians, returning to Germany in 1920. Upon his return to the laboratory, he developed and appliedcoincidence circuits to the study of nuclear reactions, such as theCompton effect,cosmic rays, and thewave–particle duality of radiation.
In 1930, he became a full professor and director of the physics department at theUniversity of Giessen. In 1932, he became director of the Physical and Radiological Institute at theUniversity of Heidelberg. He was driven out of this position by elements of thedeutsche Physik movement. To preclude his emigration from Germany, he was appointed director of the Physics Institute of the Kaiser Wilhelm Institute for Medical Research (KWImF) inHeidelberg. There, he built the first operational cyclotron in Germany. Furthermore, he became a principal in the German nuclear energy project, also known as theUranverein (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 theMax Planck Society and it then became theMax Planck Institute for Nuclear Physics. Its main building was later named Bothe laboratory.
Bothe was born to Friedrich Bothe and Charlotte Hartung. From 1908 to 1912, Bothe studied at theFriedrich-Wilhelms-Universität (today, theHumboldt-Universität zu Berlin). In 1913, he wasMax Planck's teaching assistant. He was awarded his doctorate, in 1914, under Planck.[3][4]
In 1913, Bothe joined the Physikalisch-Technische Reichsanstalt (PTR, Reich Physical and Technical Institute; today, thePhysikalisch-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]
In 1927, Bothe began the study of the transmutation of light elements through bombardment withalpha particles. From a joint investigation with H. Fränz andHeinz Pose in 1928, Bothe and Fränz correlated reaction products of nuclear interactions to nuclear energy levels.[5][6][9]
In 1929, in collaboration withWerner Kolhörster andBruno Rossi who were guests in Bothe's laboratory at the PTR, Bothe began the study ofcosmic rays.[10] The study of cosmic radiation would be conducted by Bothe for the rest of his life.[6][9]
In 1932, Bothe had succeededPhilipp Lenard as Director of thePhysikalische und Radiologische Institut (Physical and Radiological Institute) at the University of Heidelberg. It was then thatRudolf Fleischmann became a teaching assistant to Bothe. WhenAdolf Hitler became Chancellor of Germany on 30 January 1933, the concept ofDeutsche Physik took on more favor as well as fervor; it wasanti-Semitic and against theoretical physics, especially against modern physics, includingquantum mechanics and both atomic and nuclear physics. As applied in the university environment, political factors took priority over the historically applied concept of scholarly ability,[12] even though its two most prominent supporters were theNobel Laureates in PhysicsPhilipp Lenard[13] andJohannes Stark.[14] Supporters ofDeutsche Physik launched vicious attacks against leading theoretical physicists. While Lenard was retired from the University of Heidelberg, he still had significant influence there. In 1934, Lenard had managed to get Bothe relieved of his directorship of the Physical and Radiological Institute at the University of Heidelberg, whereupon Bothe was able to become the Director of theInstitut für Physik (Institute for Physics) of theKaiser-Wilhelm Institut für medizinische Forschung (KWImF, Kaiser Wilhelm Institute for Medical Research; today, theMax-Planck Institut für medizinische Forschung), inHeidelberg, replacing Karl W. Hauser, who had recently died.Ludolf von Krehl, Director of the KWImF, andMax Planck, President of theKaiser-Wilhelm Gesellschaft (KWG, Kaiser Wilhelm Society, today theMax Planck Society), had offered the directorship to Bothe to ward off the possibility of his emigration. Bothe held the directorship of the Institute for Physics at the KWImF until his death in 1957. While at the KWImF, Bothe held an honorary professorship at the University of Heidelberg, which he held until 1946.Fleischmann went with Bothe and worked with him there until 1941. To his staff, Bothe recruited scientists includingWolfgang Gentner (1936–1945),Heinz Maier-Leibnitz (1936 – ?) – who had done his doctorate with the Nobel LaureateJames Franck and was highly recommended byRobert Pohl andGeorg Joos, andArnold 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 physicistsJ. Hans D. Jensen, Helmut Steinwedel, Peter Jensen, Michael Goldhaber, andEdward Teller.[5]
Also in 1938, Maier-Leibnitz built a Wilsoncloud chamber. Images from the cloud chamber were used by Bothe, Gentner, and Maier-Leibnitz to publish, in 1940, theAtlas of Typical Cloud Chamber Images, which became a standard reference for identifying scattered particles.[5][9]
By the end of 1937, the rapid successes Bothe and Gentner had with the building and research uses of aVan de Graaff generator had led them to consider building acyclotron. By November, a report had already been sent to the President of theKaiser-Wilhelm Gesellschaft (KWG, Kaiser Wilhelm Society; today, theMax Planck Society), and Bothe began securing funds from theHelmholtz-Gesellschaft (Helmholtz Society; today, theHelmholtz Association of German Research Centres), theBadischen Kultusministerium (Baden Ministry of Culture),I.G. Farben, the KWG, and various other research oriented agencies. Initial promises led to ordering a magnet fromSiemens 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 the7Li (p, gamma) and the11B (p, gamma) reactions, and on the nuclear isomer80Br, 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 theHelmholtz-Gesellschaft, Gentner was sent to Radiation Laboratory of the University of California (today, theLawrence Berkeley National Laboratory) in Berkeley, California. As a result of the visit, Gentner formed a cooperative relationship withEmilio G. Segrè andDonald Cooksey.[19]
After the armistice between France and Germany in the summer of 1940, Bothe and Gentner received orders to inspect the cyclotronFrédéric Joliot-Curie had built in Paris. While it had been built, it was not yet operational. In September 1940, Gentner received orders to form a group to put the cyclotron into operation. Hermann Dänzer from the University of Frankfurt participated in this effort. While in Paris, Gentner was able to free both Frédéric Joliot-Curie andPaul Langevin, who had been arrested and detained. At the end of the winter of 1941/1942, the cyclotron was operational with a 7-MeV beam ofdeuterons.Uranium andthorium were irradiated with the beam, and the byproducts were sent toOtto Hahn at theKaiser-Wilhelm Institut für Chemie (KWIC, Kaiser Wilhelm Institute for Chemistry, today, theMax Planck Institute for Chemistry), in Berlin. In mid-1942, Gentner's successor in Paris, wasWolfgang Riezler [de] fromBonn.[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]
For theUranverein, 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 favorheavy water as aneutron 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 theUranverein was relinquished to the RFR in July 1942. The nuclear energy project thereafter maintained itskriegswichtig (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 andheavy water production, uranium isotope separation, and theUranmaschine (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'sInstitut für Physik was one of the nine institutes. The other eight institutes or facilities were: the Institute for Physical Chemistry at theLudwig Maximilian University of Munich, the HWAVersuchsstelle (testing station) in Gottow, theKaiser-Wilhelm-Institut für Chemie, the Physical Chemistry Department of theUniversity of Hamburg, the Kaiser-Wilhelm-Institut für Physik, the Second Experimental Physics Institute at theGeorg-August University of Göttingen, theAuergesellschaft, and theII. Physikalisches Institut at theUniversity of Vienna.[25][28][29][30]
At the end of 1957, Gentner was in negotiations withOtto Hahn, President of theMax-Planck Gesellschaft (MPG,Max Planck Society, successor of theKaiser-Wilhelm Gesellschaft), and with the Senate of the MPG to establish a new institute under their auspices. Essentially, Walther Bothe'sInstitut für Physik at theMax-Planck Institut für medizinische Forschung, inHeidelberg, 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 theMax-Planck Institut für Kernphysik (MPIK, Max Planck Institute for Nuclear Physics) on 1 October, and he also received the position as anordentlicher 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 theUranverein. However, Bothe's impatience with Nazi policies in Germany brought him under suspicion and investigation by theGestapo.[5]
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]
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 toMax Born.
Walther BotheDie Diffusionsläge für thermische Neutronen in Kohle G12 (7 June 1940)
Walther BotheDie Abmessungen endlicher Uranmaschinen G-13 (28 June 1940)
Walther BotheDie Abmessungen von Maschinen mit rücksteuendem Mantel G-14 (17 July 1941)
Walther Bothe andWolfgang GentnerDie Energie der Spaltungsneutronen aus Uran G-17 (9 May 1940)
Walther BotheEinige Eigenschaften des U und der Bremsstoffe. Zusammenfassender Bericht über die Arbeiten G-66 (28 March 1941)
Walther Bothe andArnold FlammersfeldDie Wirkungsquerschnitte von 38[34] für thermische Neutronen aus Diffusionsmessungen G-67 (20 January 1941)
Walther Bothe and Arnold FlammersfeldResonanzeinfang an einer Uranoberfläche G-68 (8 March 1940)
Walther Bothe and Arnold FlammersfeldMessungen an einem Gemisch von 38-Oxyd und –Wasser; der Vermehrungsfakto K unde der Resonanzeinfang w. G-69 (26 May 1941)
Walther Bothe and Arnold FlammersfeldDie Neutronenvermehrung bei schnellen und langsamen Neutronen in 38 und die Diffusionslänge in 38 Metall und Wasser G-70 (11 July 1941)
Walther Bothe and Peter JensenDie Absorption thermischer Neutronen in Elektrographit G-71 (20 January 1941)
Walther Bothe and Peter JensenResonanzeinfang an einer Uranoberfläche G-72 (12 May 1941)
Walther Bothe and Arnold FlammersfeldVersuche mit einer Schichtenanordnung von Wasser und Präp 38 G-74 (28 April 1941)
Walther Bothe and Erwin FünferAbsorption thermischer Neutronen und die Vermehrung schneller Neutronen in Beryllium G-81 (10 October 1941)
Walther BotheMaschinen mit Ausnutzung der Spaltung durch schnelle Neutronen G-128 (7 December 1941)
Walther BotheÜber Stahlenschutzwäne G-204 (29 June 1943)
Walther BotheDie Forschungsmittel der Kernphysik G-205 (5 May 1943)
Walther Bothe and Erwin FünferSchichtenversuche mit Variation der U- und D2O-Dicken G-206 (6 December 1943)
Fritz Bopp, Walther Bothe,Erich Fischer, Erwin Fünfer,Werner Heisenberg, O. Ritter, andKarl WirtzBericht über einen Versuch mit 1.5 to D2O und U und 40 cm Kohlerückstreumantel (B7) G-300 (3 January 1945)
Walther Bothe and Hans GeigerEin Weg zur experimentellen Nachprüfung der Theorie von Bohr, Kramers und Slater,Z. Phys. Volume 26, Number 1, 44 (1924)
Walther BotheTheoretische Betrachtungen über den Photoeffekt,Z. Phys. Volume 26, Number 1, 74–84 (1924)
Walther Bothe and Hans GeigerExperimentelles zur Theorie von Bohr, Kramers und Slater,Die Naturwissenschaften Volume 13, 440–441 (1925)
Walther Bothe and Hans GeigerÜber das Wesen des Comptoneffekts: ein experimenteller Beitrag zur Theories der Strahlung,Z. Phys. Volume 32, Number 9, 639–663 (1925)
W. Bothe and W. GentnerHerstellung neuer Isotope durch Kernphotoeffekt,Die Naturwissenschaften Volume 25, Issue 8, 126–126 (1937). Received 9 February 1937. Institutional affiliation:Institut für Physik at theKaiser-Wilhelm Institut für medizinische Forschung.
Walther BotheThe Coincidence Method,The Nobel Prize in Physics 1954, Nobelprize.org (1954)
Walther BotheDer Physiker und sein Werkzeug (Gruyter, 1944)
Walther Bothe and Siegfried FlüggeKernphysik und kosmische Strahlen. T. 1 (Dieterich, 1948)
Walther BotheDer Streufehler bei der Ausmessung von Nebelkammerbahnen im Magnetfeld (Springer, 1948)
Walther Bothe andSiegfried Flügge (editors)Nuclear Physics and Cosmic Rays FIAT Review of German Science 1939–1945, Volumes 13 and 14 (Klemm, 1948)[35]
Walther BotheTheorie des Doppellinsen-b-Spektrometers (Springer, 1950)
Walther BotheDie Streuung von Elektronen in schrägen Folien (Springer, 1952)
Walther Bothe and Siegfried FlüggeKernphysik und kosmische Strahlen. T. 2 (Dieterich, 1953)
Karl H. Bauer and Walther BotheVom Atom zum Weltsystem (Kröner, 1954)
^abcdefgMehra, Jagdish, andHelmut Rechenberg (2001)The Historical Development of Quantum Theory. Volume 1 Part 2 The Quantum Theory of Planck, Einstein, Bohr and Sommerfeld 1900–1925: Its Foundation and the Rise of Its Difficulties. Springer,ISBN0-387-95175-X. p. 608
^abcdefghWalther Bothe and the Physics Institute: the Early Years of Nuclear Physics, Nobelprize.org.
^"The Nobel Prize in Physics 1954".nobelprize.org. Retrieved23 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 ...
^Ermenc, Joseph J, ed. (1989).Atomic Bomb Scientists: Memoirs, 1939-1945. Westport, CT & London: Meckler. pp. 27, 28.ISBN0-88736-267-2.
^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.
^abMacrakis, Kristie (1993).Surviving the Swastika: Scientific Research in Nazi Germany. Oxford. pp. 164–169.ISBN0195070100.{{cite book}}: CS1 maint: location missing publisher (link)
^Mehra, Jagdish and Rechenberg, Helmut (2001)The Historical Development of Quantum Theory. Volume 6. The Completion of Quantum Mechanics 1926–1941. Part 2. The Conceptual Completion and Extension of Quantum Mechanics 1932–1941. Epilogue: Aspects of the Further Development of Quantum Theory 1942–1999. Springer.ISBN978-0-387-95086-0. pp. 1010–1011.
^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.
^Präparat 38,38-Oxyd, and38 were the cover names for uranium oxide; seeDeutsches Museum.
^There were 50-odd volumes of the FIAT Reviews of German Science, which covered the period 1930 to 1946 – cited byMax von Laue in Document 117,Hentschel, 1996, pp. 393–395. FIAT: Field Information Agencies, Technical.
Hentschel, Klaus; Hentschel, Ann M., eds. (1996).Physics and National Socialism: An Anthology of Primary Sources. Birkhäuser.ISBN0-8176-5312-0.
Walker, Mark (1993).German National Socialism and the Quest for Nuclear Power 1939–1949. Cambridge.ISBN0-521-43804-7.{{cite book}}: CS1 maint: location missing publisher (link)
Wikimedia Commons has media related toWalther Bothe.
Walther BotheThe Coincidence Method,The Nobel Prize in Physics 1954, Nobelprize.org (1954). Due to Bothe's illness, this lecture was not delivered orally.
Walther Bothe and the Physics Institute: the Early Years of Nuclear Physics, Nobelprize.org.
