Walther Bothe – Biography of Walther Bothe

The Nobel Prize-winning German physicist, Walther Wilhelm Georg Bothe He was born on January 8, 1891 in Oranienburg, near Berlin.

From 1908 to 1912 he studied physics at the University of Berlin, where he was a student of Max Planck, obtaining his doctorate just before the outbreak of the 1914-1918 war. From 1913 to 1930 he worked at the Physikalisch-Technische Reichsanstalt in the same city, where he became an extraordinary professor at the local university. In 1930 he was appointed professor of physics and director of the Institute of Physics at the University of Giessen.

In 1932 he was appointed Director of the Physics Institute of the University of Heidelberg, in succession to Philipp Lenard, becoming in 1934 Director of the Physics Institute of the Max Planck Institute for Medical Research in that city. At the end of the Second World War, when this Institute was taken over for other purposes, Bothe He returned to the University Physics Department, where he taught until the illness that had impeded him for several years forced him to restrict the scope of his work. However, he was able to supervise the work of the Institute of Physics at the Max Planck Institute and continued to do so until his death in Heidelberg on February 8, 1957.

The scientific work of Bothe It coincided with the opening of the vast field of nuclear physics and the results it obtained led to new perspectives and methods.

He was taken prisoner by the Russians during World War I and spent a year in captivity in Siberia. This year he devoted himself to mathematical studies and learning the Russian language; in 1920 he was sent back to Germany.

He then collaborated with Hans Geiger at the Physikalisch-Technische Reichsanstalt in Berlin. Together with Geiger, whose influence determined much of his scientific work, he published, in 1924, his method of coincidence, by which important discoveries were subsequently made. It is based on the fact that when a single particle passes through two or more Geiger counters, the pulses of each counter are practically coincident in time. The pulse from each counter is sent to a matching circuit that indicates pulses that are matched in time. Coincident Geiger counter arrays select particles moving in a certain direction and the method can be used, for example, to measure the angular distribution of cosmic rays. Bothe applied this method to the study of the Compton effect and other problems in physics.

Together, he and Geiger clarified ideas about the small-angle scattering of light rays and Bothe summarized his work on this problem in his article Handbuch published in 1926 and 1933, laying the foundations of modern methods for the analysis of scattering processes. From 1923 to 1926, Bothe he concentrated especially on experimental and theoretical work on the corpuscular theory of light. Some months before the discovery of the Compton effect, he had observed, in a hydrogen-filled Wilson chamber, the short path of the recoil electrons in X-rays and worked further in the direction of the emission of photoelectric electrons. Together, he and Geiger related the Compton effect to the theory of Bohr, Kramers, and Slater, and the results of their work provided strong support for the corpuscular theory of light.

In 1927, Bothe he further clarified, through his method of coincidence, ideas about light quanta in an article on light quanta and interference.

In the same year he began to study the transformation of light elements by bombardment with alpha rays. Until now, the resulting fission products had been seen by the eye only as scintillations, but Bothe, in collaboration with Fränz, made it possible to count them by means of his needle counter.

In 1929, in collaboration with W. Kolhörster, Bothe introduced a new method for the study of cosmic and ultraviolet rays by passing them through properly arranged Geiger counters, and by this method he demonstrated the presence of penetrating charged particles in the rays, and defined the individual ray paths.

For his discovery of the method of coincidence and the discoveries made later by him, which laid the foundation for nuclear spectroscopy, Bothe He was awarded, together with Max Born, the 1954 Nobel Prize in Physics.
In 1930, BotheIn collaboration with H. Becker, he bombarded beryllium of mass 9 (and also boron and lithium) with alpha rays derived from polonium, and obtained a new form of radiation that was even more penetrating than the harder gamma rays derived from radium; This led to the discovery of the neutron, made by Sir James Chadwick in 1932.

In Heidelberg, Bothe was able, after many difficulties, to obtain the necessary money to build a cyclotron. During the war of 1939-1945, he worked on the theory of neutron diffusion and measurements related to these.

In June 1940 he published his Cloud Chamber Figures Atlas.

The skills of Bothe they weren’t just limited to physics. He had an amazing gift for concentration and his habit of making the best use of his time allowed him to work at great speed. He gave his hobbies and recreations the same concentration and intensity of effort that he gave to his scientific work. The main of them was music and painting. He attended many musical concerts and played the piano himself, being especially fond of Johann Sebastian Bach and Ludwig van Beethoven. During his vacations he visited the mountains and did many oil and water paintings in his own style. He admired the French Impressionists and was eager and vigorous in his discussions of the merits and demerits of various artists.

Bothe married Barbara Below from Moscow. His death preceded hers by a few years. They had two children.