Walther Bothe was a brilliant German nuclear physicist who, in 1954, won the physics Nobel Prize with Max Born “for the coincidence method and his discoveries made therewith”.
His Early Life and Education
Walther Wilhelm Georg Bothe was born on the 8th of January, 1891 to Charlotte Hartung and Fritz Bothe, a merchant. He was from Oranienberg, a town in Brandenburg, Germany.
From 1908 to 1912 he studied physics, chemistry and mathematics at the University of Berlin. He continued his education and studied for a doctorate, under the brilliant physicist Max Planck, which he was awarded in 1914. His thesis concerned the molecular theory of refraction, reflection, dispersion, and extinction.
During World War I, Bothe was a machine gunner in the German army. In 1915 was captured by the Russians and spent time in Siberia during his captivity. Being the consummate scientist, he chose to spend his time as a prisoner of war learning how to speak and read Russian and continued his research studies. He also found a wife.
Returning to Germany in 1920, with his Russian bride, Barbara Below, and he obtained a position at the radioactive laboratory of Physikalisch-Technische Reichsanstalt. He became director of the laboratory in 1927. Here he collaborated with Hans Geiger and made his most important discoveries.
During this time, Bothe was also a lecturer at the University of Berlin.
In 1931 he took a professorship at the University of Giessen and in 1934 he became director of the Physics Institute of the Max Planck Institute for Medical Research at Heidelberg, where he remained until his death.
Bothe also moved his work to the University of Heidelberg in 1934 and was a professor there from 1946 to 1957.
Between 1923 and 1926 Bothe concentrated much of his work on the scattering of alpha and beta rays.
Bothe worked with Hans Geiger and together they researched the emission of electrons by x-rays to test Bohr’s quantum model of the atom. They used two Geiger counter tubes, one to detect the scattered x-rays and the other to detect the recoiling electrons, to study the coincidences of individual Compton collisions.
In 1924, Bothe then devised a coincidence circuit – this circuit was considered the first AND logic gate. Running several counters in coincidence enabled the scientists to calculate the angular momentum of a particle and thus they demonstrated that momentum and energy are conserved at the atomic level.
Four years later in 1929, Bothe researched the Compton Effect further and used the coincidence method again with Werner Kolhörster to establish the particle nature of cosmic rays. Their experiments showed that the rays were composed of gamma rays and high energy particles.
Bothe was also interested in the transmutation of elements and in 1930, with Herbert Becker, he obtained a never-before-seen form of radiation from beryllium that had been bombarded by alpha particles. This study led Sir James Chadwick to discover the neutron in 1932.
He supervised the construction of the first German cyclotron, a device that can accelerate particles (like protons) along a spiral path, which was completed in 1943.
During the Second World War he worked on nuclear energy research.
After the war, Bothe used the German cyclotron to produce radioactive isotopes for his medical studies.
In addition to numerous scientific articles, he published “Nuclear physics and Cosmic Rays” in 1948.
He was awarded the Max Planck medal in 1953.
Bothe received the 1954 Nobel Prize in Physics “for the coincidence method and his discoveries made therewith” together with Max Born.
Bothe married Barbara Below from Moscow in 1920 and they had two daughters.
He enjoyed vacationing in the mountains and would often paint using oils or watercolors. He was also an excellent pianist and he enjoyed listening to Beethoven and Bach.
Walther Wilhelm Georg Bothe died on 8 February 1957, aged 66 in Heidelberg, Germany.