Nuclear chemistry particle accelerators

MCMILLAN, EDWIN M. (1907-1991). An American physicist who won the Nobel prize in chemistry in 1951 along with Glenn T. Seaborg lor their discoveries In the chemistry of the transuranium elements. His work included research in nuclear physics and particle accelerator development as well as microwave radar and sonar. He and his colleagues discovered neptunium and plutonium. He was the recipient of the Atoms for Peace prize in 1963. His Ph D. in Physics was awarded from Princeton University. 

Using nuclear chemistry, scientists today can change one element into another and even produce elements artificially. How are elements made artificially Some are produced as by-products in nuclear reactors. However, most are made by bombarding nuclei with small particles that have been accelerated to high speeds. This is done mainly in three instruments, shown in Figure 21.19. 

With the development of nuclear reactors and charged particle accelerators (commonly referred to as atom smashers ) over the second half of the twentieth century, the transmutation of one element into another has become commonplace. In fact some two dozen synthetic elements with atomic numbers higher than naturally occurring uranium have been produced by nuclear transmutation reactions. Thus, in principle, it is possible to achieve the alchemist s dream of transmuting lead into gold, but the cost of production via nuclear transmutation reactions would far exceed the value of the gold. SEE ALSO Alchemy Nuclear Chemistry Nuclear Fission Radioactivity Transactinides. 

Research Chemist Some nuclear chemists specialize in studying the newest and heaviest elements. To produce heavy elements, a nuclear chemist works with a large team, including physicists, engineers, and technicians. Heavy elements are produced by collisions in a particle accelerator. The nuclear chemist analyzes the data from these collisions to identify the elements and understand their properties. For more information on chemistry careers, visit glencoe.com. 

The majority of radioactive nuclides (radionuclides) are man-made, created by transforming a stable nuclide into an unstable state by irradiation with neutrons, protons, deuterons, alphas, gammas, or other nuclear particles. The source of these particles may be a radionuclide, a nuclear reactor, or a particle accelerator (Van de Graaff, cyclotron, linac, etc.). The tremendous variety of radionuclides discovered in this manner has given rise to many applications in physics, chemistry, biology, and, of course, medicine. The production of those medically useful radionuclides created by exposure to neutrons in a nuclear reactor is discussed in this chapter. 

It was more than 50 years ago that Yukawa predicted the existence of a new particle, a meson, that should mediate nuclear forces. Before such particle was found in cosmic rays, however, another new particle was discovered. It was quite unexpected and Yukawa him lf at first mistook it for his predicted particle. This new particle was initially called a p meson, but is now known as a muon. Muons have peculiar but useful properties as is described in the following sections and, thanks to the recent development of high energy accelerators, can be obtained in copious amounts. Thus, they have become an important tool in many fields of physical chemistry and materials science. 

A short description of possible nuclear applications of boron-based materials had been done by Potapov (1961) in an old overview that included the nuclear power industry (e.g., control rods of nuclear reactors) solid-state electronics (e.g., counters of neutrons and neutron energy sensors) radiation chemistry (e.g., acceleration of technological processes) etc. For these purposes, "B nuclei are useless, but °B nuclei are useful due to a large cross section of interaction with thermal neutrons, °B converts them into heavy ionizing particles. Besides, °B isotope is applicable for neutron radiation protection (Stantso 1983) and also in medicine, e.g., in boron neutron capture therapy (BNCT) for treating cancer tumors (Desson 2007). 

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