Bothe (Bothe), Walter( German physicist, Nobel Prize in Physics, 1954)
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Biography Bothe (Bothe), Walter
June 8, 1891, Mr.. - February 8, 1957
German physicist Wilhelm Walter to Boy George was born in Oranienburg.
His father, Frederick Botha, was a merchant. In 1908, Mr.. B. enrolled at Berlin University, where he studied physics, mathematics and chemistry. In 1914, working under the leadership of the Max Planck. He received his doctorate in theoretical study of the interaction of light with molecules.
During World War II B. served in the Germany Army. In 1915, Mr.. He was captured by Russian and sent to Siberia, where he studied Russian language and was able to continue his studies in theoretical physics. Returning to Germany in 1920, he began working under the leadership of Hans Geiger (inventor of a Geiger counter) in the radiation laboratory of the State Physical-Technical Institute, where he worked briefly in 1913, Mr.. (Later, he believed that it was Geiger sent his effort in the direction of physics.) Simultaneously B. taught physics at the University of Berlin.
In the early 20-ies. B. experimental and theoretical study of deviations of alpha and beta particles in matter. Most of the work in this area is the single particle interactions with individual atoms. However B. studied much more difficult case, when the fast particles, fly through a substance interacts with a large number of atoms, with each act of interaction leads to a deviation of the particle, proportional to its power. Since the passage through the body of a strong single interaction is unlikely that complete rejection of the particle is determined mainly by the large number of small deviations. To solve this problem B. developed special statistical approach.
During the first two decades of XX century. Max Planck, Albert Einstein, Niels Bohr and others created the quantum theory, the basis for studying atomic and subatomic systems. This theory, based on the idea that energy is transferred to discrete chunks, or quanta, resolved some of the dilemmas of classical physics, but instead put their own problems. From quantum theory it clear that light, as is generally the electromagnetic field, has the characteristics of both waves and particles - dualism, which many physicists perceived difficulty. Experiments, . conducted in the early 20's, the, . confirmed the idea, . that objects, . are very long seen as waves (such, . the light), . can behave like particles, . while those, . considered that the particles (eg, . electron), . can behave like waves,
. One of the most impressive evidence of this was made in 1923. Arthur X. Compton opening (now known as the Compton effect), which consists in the fact that X-rays. were previously considered waves are scattered by electrons in the material as if they were particles.
In 1924, Mr.. Bohr. Hendrik Kramers and John Slater tried to solve the problem of wave-particle, proposed a new formulation of quantum theory, which rejected some of the fundamental principles of classical physics. According to well-known conservation laws, energy and momentum are preserved, ie. for any interaction the total energy and momentum of a system of bodies before the interaction are full of energy and momentum after the interaction. Bohr, Kramers and Slater suggested that at the atomic level, with individual particle interactions should not be saved no energy, no momentum, they remain only in the sum of many individual interactions. However, the then existing methods of investigating the elementary particles are not suitable for testing the statistical interpretation of conservation laws proposed by Bohr and his colleagues. After reading their article, B. decided to develop a methodology that would confirm their hypothesis.
Experiment Compton in 1923. showed that when quanta of X-rays are scattered by collisions with electrons, they lose part of its energy and momentum. Compton predicted and CH.T.R. Wilson confirmed that the parties involved in such collisions electrons receive benefits, ie. running out of atoms. B. understood that if the classical laws of conservation are at the atomic level, the collision shall be obtained as the scattered quantum, hook and batted electron: energy and momentum lost by the quantum must transition to electronic. On the other hand, if a valid statistical interpretation of the proposed preserve, then at each given collision should be only an accidental relationship between quantum dissipation and knocking out an electron from the atom. Therefore B. decided to use for testing the hypothesis of Bohr effect of Compton.
Original Geiger, invented in 1913, could register only heavy charged particles, but by 1924. Created a modified Geiger counter, called a needle, which was capable of detecting electrons. Working with Geiger, B. invented a special method of using this counter. subsequently received the name 'coincidence method'. Two needle-shaped counter, filled with hydrogen, have been linked so that when they are directed beam of X-rays, collisions between photons and electrons beams of hydrogen atoms occur in the first counter. Recoil electrons were recorded by this counter, while the scattered photons were in the second, where they beat the much smaller number of electrons recorded by the second counter, thereby demonstrating the presence of scattered photons. Arise in particle detection electrical impulses counters are automatically recorded, enabling the researcher to decide whether they fit in time.
B. and Geiger found that the simultaneous recording of the scattered photon and electron knocked out, too often, that it could be considered accidental, and their statistical evaluation showed that the two particles always occur in each collision. Hence, they concluded that the statistical hypothesis is incorrect Bora. Their study showed that the classical conservation laws valid for individual acts of interactions at the subatomic level. Their conclusion, accepted by the Bohr and other physicists, influenced the development in the 20-ies. quantum mechanics, the complex mathematical treatment of quantum theory.
. Coincidence method B., . for which he later received the Nobel Prize in Physics, . has become an important tool in modern systems of registration and measurement of particles, . Although physicists today use much more sophisticated counters, . record only coincident events,
. For example, when monitoring the particles released by a nuclear reaction, so the researchers can adjust their instruments so that they recorded only the data that meets a number of these criteria. They can then perform a statistical analysis of the data to find out whether it is a coincidence or about those reactions, they are looking for.
Since 1926. B. studied the transmutation of elements that occur in the bombardment of nuclei by alpha particles, and in 1930. He and his colleagues discovered a new, having high penetrating radiation, which occurred in the bombardment of alpha particles of beryllium. This work led to the discovery in 1932. neutron by James Chadwick. In 1929, Mr.. B. together with Werner Kolhorster used a coincidence method for the detection of cosmic rays. In these studies, it was found that cosmic rays are a stream of high energy particles, but not gamma rays, as generally believed.
In 1930. B. became director of the Physics Institute at the University of Hesse. Two years later he was appointed director of the Physics Institute at the University of Heidelberg, and in 1934. he was appointed director of the Physical Institute at the Institute of Medical Research in Heidelberg, Max Planck. The Max Planck Institute, he oversaw the construction of the cyclotron, a particle accelerator used in nuclear research. Construction was completed in 1943
During the Second World War B. was one of the leading participants of the project on nuclear energy, led by Werner Heisenberg. He studied the properties of nuclei of uranium and developed the theory of neutron diffusion, which describes the scattering of neutrons and their absorption and creation of systems containing fissionable elements such as uranium. After the war, B. returned to the problems of scattering of electrons and cosmic rays, he also contributed to the theoretical understanding of beta decay and gamma-ray nuclei.
In 1954, Mr.. B. was awarded the Nobel Prize in Physics "for the method of coincidences and made in connection with the opening '. He shared the award with Max Born, who was rewarded for his contributions to quantum mechanics. Suffering serious violations of blood and bedridden, B. could not attend the ceremony and sent his daughter to receive the award on his behalf. 'I think the main lesson that I got from GM - wrote to B. in his Nobel lecture - was the fact that among the many possible and probably useful experiments to be able to choose the one that is most pressing at the moment and hold it, using the simplest equipment. "
. Despite his illness, B
. continued to lead the Institute in Heidelberg. His illness caused him much suffering and prevented to fully enjoy the glory which came.
B. married in 1920. on Muscovite Barbara Belova, they had two children. Known for its serviceability, B. was severe in the laboratory, but cordial and hospitable home. He was a gifted artist, who wrote both oil and watercolor, and a passionate pianist who especially loved to play Bach and Beethoven. He died in Heidelberg on Feb. 8, 1957
In addition to the Nobel Prize, B. was awarded the Medal of the Max Planck Germanskogo Physical Society and the Grand Cross of the Order "For federal service 'of the Government of Germany. In 1952, Mr.. He became a Knight of the Order of Government of Merit in the science and art '. He was a member of the Academies of Sciences in Heidelberg and GцTttingen, and the Saxon Academy of Sciences in Leipzig.