Libby (Libby), Willard F.( The American chemist, Nobel Prize in Chemistry, 1960)
Comments for Libby (Libby), Willard F.
Biography Libby (Libby), Willard F.
December 17, 1908, Mr.. - September 8, 1980
The American chemist Willard Frank Libby was born in Grand Valley (Colorado), in the family Oura Edward Libby, a farmer with a three-class education, and Willow Mae (Rivers) Libby. In Willard, the couple Libby still had two sons and two daughters. When he was 5 years old, his family moved to a ranch near Sebastopol in northern California. L. attended to first place in two rooms primary school, and in 1926. graduated high. He dreamed of becoming a mining engineer and receiving parents' blessing, he entered the University of California at Berkeley, to acquire the necessary specialty. Began his studies at the university, however, he changed the children's dream, thinking that chemistry is much more interesting. After studying chemistry, physics and mathematics, L. in 1931. received a bachelor's degree in chemistry. Two years later, after graduate school, where he led by physical chemist Gilbert H. Lewis and Wendell M. Latimer studied radioactive nuclei with low energy, L. was awarded a doctoral degree and was appointed professor of chemistry.
. Isotopes are varieties of a chemical element with the same atomic number (because their nuclei contain the same number of protons) but different atomic mass, ie
. with different numbers of neutrons. They have the same chemical properties but slightly different from each other on the physical properties. Radioactive isotopes have unstable nuclei that decay by emitting alpha, beta and gamma-rays. The radioactive nucleus as a tracer chemical reactions for the first time applied chemist Georg (Gyц╤rgy) de Hevesy. To accurately measure a small number of radioactive nuclei of radiation emitted by these nuclei in the analysis must be isolated both from the background cosmic radiation and radiation from radioactive nuclei in the environment. German physicist Walther Bothe developed a method of coincidences, in which multiple electrical detectors are counted simultaneously occurring radioactive radiation. Established L. anti-coincidence method, which is a variant of the method Bothe, in the measuring chamber are detectors and internal and external radiation. This method allowed us to significantly reduce the influence of background radiation on the measurement of very low levels of radiation. While still a graduate student, h. made around the same time as the Hevesi, discovery, finding that the element samarium has a low radioactivity.
In 1941, Mr.. L., which by this time held the post of associate professor, took a sabbatical and spent his conducting studies at Princeton University on a scholarship Guggenheim. In December 1941, Mr.. The United States entered World War II, and A. as a participant in the Manhattan project - undertaken by the U.S. efforts to develop nuclear weapons - has joined Harold K. Urey, who then worked at Columbia University. Under this project, L. developed the gaseous diffusion technology to separate uranium isotopes, which was necessary to build an atomic bomb. At the end of the Second World War, he became a full professor of Department of Chemistry, University of Chicago, where, in addition, conducted research in the University Institute for Nuclear Research.
In 1939, Mr.. Serge Korff, who works at New York University, found that when cosmic rays penetrate the atoms in the upper atmosphere, they cause the neutron flux. Other evidence indicates that nitrogen, of which approximately 80 per cent is the atmosphere easily absorbs neutrons and then decays into radioactive carbon, also known as radiocarbon, or carbon-14. L. advanced the theory that the bombardment of cosmic rays cause the transformation of atmospheric nitrogen into radioactive carbon. He quickly oxidized in air to carbon dioxide (carbon dioxide) and is absorbed by plants through photosynthesis. Any organism that consume these plants absorb along with the radioactive carbon atoms. L. suggested that the radioactive carbon is generated at a constant speed and that, once hitting a molecule, it remains in it. Hence the scientist came to the conclusion that all living beings have a constant level of radioactivity, which falls after the death of the organism. The life of a radioactive isotope is determined by its half-life - a segment of time needed for the decay of half of the amount of substance. As established in 1940. Martin Kamen, a half-life of carbon-14 is 5730 years - a relatively short period of time compared with the age of the Earth, but long enough to establish equilibrium in the process of formation and decay of carbon-14. L. came to the conclusion that 'it should be possible by measuring the remaining radioactivity measured the time that has passed since the death if it occurred in the period from 500 to 30 thousand. years ago '.
To test their hypothesis L. constructed a Geiger counter, the walls of which were thickened dvadtsatisantimetrovym layer of iron for absorption of terrestrial radiation. Such a Geiger counter registers the cosmic rays that penetrate through the thick wall. As with the studies in preparation for doctoral dissertation, . Geiger counters with thickened walls recorded the penetrating particles, . The central computer to measure the radioactivity of the sample included in the one-thousandth of a second,
. Maximum sensitivity to the radioactivity emitted dating from the sample is achieved by putting pure carbon (in the form of soot) on the inner wall of the sensitive detector. Later L. found that the sensitivity with this method is further enhanced if the carbon is taken in the form of gas - or carbon dioxide or acetylene. In a trillion carbon atoms is found about one radioactive atom. L. verified the accuracy of this method by measuring the radioactivity of samples of redwood and fir, whose exact age was established by counting the annual rings. He also subjected the experimental analysis of the lessons during archaeological excavations subjects whose age was already known - such as a piece of wood from the funerary boat of the Egyptian Pharaoh, taken at the Chicago Museum of Natural History. L. received brilliant confirmation of his theory, and invented a method of dating has become widely used in archeology and geology.
Checked for radioactivity remains of animals and plants received from all over the world - from the North Pole to the South, L. found some discrepancies in the data associated with the latitude at which the samples were found. Among the archaeological finds, have carefully dated using the method of LA, were as follows: pieces of linen cloth, which were tied manuscripts found in the Dead Sea, the bread from the house in Pompeii, buried under volcanic ash in 79 g. BC, charcoal from the parking lot of ancient people at Stonehenge (England) and cob from a cave in New Mexico. L. also found that the last glacial period in North America was over 10 thousand. years ago, not 25 thousand, as was previously estimated by geologists. The method of carbon dating quickly gained recognition as the primary method of setting the dates of events that occurred in the last 70 thousand. years.
The impact of cosmic rays on the upper atmosphere also leads to the formation of small amounts of tritium - a radioactive isotope of hydrogen, the nucleus of an atom which contains 1 proton and 2 neutrons, and the half-life is 12 years. Thus, the concentration of tritium can be used as a tracer of atmospheric moisture and hydrological system of the Earth. With tritium L. studied the water cycle, the composition of ocean waters and age wines.
The scientist was included President Dwight D. Eisenhower in the Atomic Energy Commission, USA. There, from 1954 to 1959. L. dealt with problems fallout from the explosion of atomic bombs and was involved in the implementation of international programs of nuclear technology for peaceful purposes, such as 'Over the peaceful atom'. After retiring from the Atomic Energy Commission in 1959. He began working at the Department of Chemistry, University of California at Los Angeles, and 3 years later was appointed director of the Institute of Geophysics and planetary physics. The post is a scientist combined with his work at UC until resignation in 1976. His research interests expanded to include geochemistry, planetary atmospheric problems, the study of the lunar surface, control of the environment, protection from earthquakes and civil defense.
In 1960, Mr.. L. was awarded the Nobel Prize in Chemistry 'for the introduction of the method using carbon-14 for age determination in archeology, geology, geophysics and other fields of science'. In his Nobel lecture L. said: 'By itself, I proposed a method of dating requires caution, but it may apply well-trained personnel, be clean, orderly, serious manner and with adequate practical skills'. 'Under such circumstances, the method of radiocarbon dating ... can really help to look through the back pages of history and humanity to tell some more about his predecessors, and therefore - he concluded - and about his future. "
In 1940. L. married schoolteacher Leonore Lyusinde Hickey. In the couple had two daughters-twins. In 1966, Mr.. the marriage broke up, and L. joined their fate with Leone Woods, Marshall, Professor of the Environment, University of California at Los Angeles. The scientist was a man tall, stout build. Glenn T. Seaborg described him as 'diligent, patient and capable teacher', whose 'professional career because of his enormous curiosity was extremely versatility and breadth of interests'. L. died in Los Angeles on Sept. 8, 1980, Mr.. from pneumonia and a blood clot in the lung. In addition to the Nobel Prize, A. was awarded a medal of Charles Frederick Chandler, Columbia University (1954), . Elliott Cresson Medal Franklinovskogo Institute (1957), . Medal Willard Gibb of the American Chemical Society (1958) and Medal Dey Geological Society of America (1961),
. He was a member of the U.S. National Academy of Sciences, the American Academy of Arts and Sciences, the American Philosophical Society, the Heidelberg Academy of Sciences, the Bolivian Anthropological Society and the Royal Swedish Academy of Sciences.