Rainwater (Rainwater), James

December 9, 1917, Mr.. - May 31, 1986
American physicist Leo James Rainwater was born in g. Kauns (Idaho) in the family construction engineer and manager of department store, Leo James Rainwater Jasper and Edna Eliza (nee Tighe) Rainwater. After the death of his father, followed in 1918. during epidemics of influenza, the family moved to r. Hanford (Calif.), where the mother married a second time. Children and youth boys were at Hanford, where he showed the ability to chemistry, physics and mathematics. After taking first place at the Chemistry Olympiad, held in the means of the California Institute of Technology (Caltech), he was admitted to this institution as a student of chemistry, but soon chose their main subject of physics. At Caltech R. studied physics under the guidance of Dr. Charles. Anderson and his studies on the biology led Thomas Hunt Morgan. After receiving a bachelor's degree in physics in 1939. R. graduate studies at Columbia University, where its leaders were IA. Rabi, Enrico Fermi, Edward Teller and other prominent physicists.
When the United States entered World War II, P. interrupted his dissertation research, taking part in the Manhattan Project as a member of the Office of Research and Development Working under the beginning with J. R. Dunning, he used a cyclotron (type of particle accelerator) at Columbia University for investigating the behavior of atomic nuclei by bombarding them with neutrons. After the war, received R. data had been declassified, and in 1946. Research for the work he was awarded a doctoral degree.
Left at Columbia University as a teacher, P. continued his work in the field of experimental physics. In 1946, Mr.. Columbia University was allocated funds to build Nevisskoy cyclotron laboratory in t. h. and synchrocyclotron able to accelerate particles to much higher energies than could be obtained in the earlier versions cyclotrons. R. from the outset been closely involved in the creation of the accelerator, which came into operation in 1950, Mr.. By the time he and his staff, William Y. Heyvensom Jr. and By Tszyansyun have measured the interaction cross section of neutrons with the majority of nuclei. The new accelerator allowed to conduct similar experiments with other particles, . besides neutrons, . such as muons (reminiscent of electrons, . but about 200 times more massive and unstable, . decomposing mere 2, . 2 million seconds) and pi-meson (short-lived particles - carriers of the strong nuclear interaction, . not giving the nuclei disintegrate).,
. In 1949 1950 he
. Danish physicist Aage Bohr, who conducted the study at Columbia University, was a neighbor P. the office. Two physics waged a never-ending conversation about the fundamental structure of nuclei. At that time there were two main models of the kernel: drop model and shell model. Both models are known to originate from the action of the fundamental forces between protons and neutrons (collectively known as nucleons), forming the nucleus, and sought to predict the properties of tens or hundreds of interacting nucleons.
. Trickle model was proposed by the father Aage Bohr, Niels Bohr, in 1936
. It proceeds from the assumption that the nucleus behaves like a drop of liquid that can fluctuate and change its shape
. Although the droplet model would satisfactorily explain nuclear fission, but was insufficient to describe other important properties of its. In the shell model, proposed in 1949. Maria Goeppert-Mayer, and J. Hans D. Jensen, nucleons move in an independent concentric orbits, or shells: their movement is much like the motion of electrons in an atom, except that in the case of nucleons there acting on their central force. According to the shell model, the force acting on one nucleon, the sum of the forces with which it acts on each of the other nucleons in the. The sum of these forces generates a force field, which Goeppert-Mayer and Jensen assumed spherically symmetric. Although the shell model successfully to predict the possible energy in the excited states of the nucleus, in the rest of her unlucky. In particular, the shell model was not able to take into account the fact that the distribution of electric charge around some nuclei are not completely spherically symmetric.
At the end of 1949. Charles X. Townes at Columbia University made a presentation on the discrepancies between the predictions of the theory of shells and the experimental data. Listening to the report Townes, F. thinking about how to explain these discrepancies. It occurred to him that the orbits of the shell-filled core can be deformed by centrifugal forces and take a form more reminiscent of an ellipsoid than a sphere. After persuading Aage Bohr in the merits of this idea, he in 1950, Mr.. published his hypothesis, and turned to experimental verification for it.
Bohr, who pondered on similar ideas back in the same year in Copenhagen determined to develop a complete theory of behavior of the kernel. Together with Ben P. Mommelsonom he published in 1952. collective model of the nucleus, using the idea of P. to agree 'hydrodynamic' behavior described by the liquid-drop model, with the orbital properties of the nucleons in the shell model.
. According to Bohr and Mottelson, collective action nuklonv forcing the kernel to behave like a drop of liquid
. However, the core has a shell structure that can deform into a kind of an ellipsoid. These deformations appear on the surface in the form of vibrations and rotation. When the outer shell is completely filled, the kernel is spherically symmetric. But when the outer shell is filled only partially, the shape of the nucleus is deformed. Bohr and Mottelson have found that in such deformed nuclei are possible fluctuations, accompanied by changes in size, surface waves and the rotation. Such new collective action could not be predicted by the shell model, because this model ignores the interaction between the nucleons. Using the collective model for calculating the properties of deformed nuclei and analyzing the huge amount of experimental data, Mottelson and Bohr in 1953. confirmed the hypothesis of R.
Meanwhile P. returned to his experimental studies at Columbia University synchrocyclotron. Together with Val L. Fitch R., investigating in 1953. muons emitted X-rays, found that existing estimates of the size of a proton were too high.
In 1952, Mr.. R. was appointed full professor at Columbia University. From 1946 to 1978. He was associated with Nevisskoy Cyclotron Laboratory, twice, from 1951 to 1953. and from 1956 to 1961, while he was its director.
R., Aage Bohr and Ben Mottelson in 1975. were awarded the Nobel Prize in Physics "for his discovery of the relationship between collective motion and the motion of particles in atomic nuclei and for the development of the theory of nuclear structure on the basis of this connection '. When presenting the winners of Sven Johansson, a member of the Royal Swedish Academy of Sciences, called their work 'inspiring impetus for intensive research in nuclear physics'. In his Nobel lecture P. summarized the results of previous studies, which led him to discoveries and their confirmation.
In 1942, Mr.. R. married Emma Louise Smith. Married couple have a daughter, who died in infancy, and three sons. At leisure R. studied geology and astronomy, and loved listening to classical music. He died in Yonkers (New York) May 31, 1986, shortly after retirement from Columbia University.
In addition to the Nobel Prize, P. was awarded the memory of Ernest Orlando Lawrence physics Atomic Energy Commission, United States (1963). He was a member of the U.S. National Academy of Sciences, Council of the Institute of Electrical and Electronics Engineers, New York Academy of Sciences, the American Association of Basic Sciences and the American Physical Society.