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'''Радиохемија''' је грана [[физичка хемија|физичке хемије]] која се бави испитивањем физичких и хемијских особина [[радиоактивност|радиоактивних]] [[изотоп]]а и њиховим разноврсним применама.
<!--Radiochemistry is such a broad term that it sometimes is defined so that it encompasses many of the other terms defined here, such as hot-atom chemistry. We'll define the field as the collection of methods and techniques that use radioactivity to follow chemical processes. In addition to hot-atom chemistry, we'll include the use of radiotracers: the incorporation of small amounts of radioactive isotopes into usually nonradioactive molecules so that concentrations of these species and their reaction products can be detected easily. The presence of radioactivity is incidental to the reaction. The reaction proceeds as if the radioactivity were not present, but the radioactive "tag" permits observation of reaction products, yields, and mechanisms otherwise not possible. Analytical, biological, and medical applications are obvious. The techniques of radiochemistry are also used to detect production of new elements by nuclear chemists and physicists following bombardment of suitable precursors in particle accelerators.-->
[[Радиоактивност]] је појава да [[хемијски елемент]], због унутрашње нестабилности [[атомско језгро|језгра]], спонтано емитује зрачење. При томе тај радиоактивни елемент може да остане хемијски неизмењен (гама-распад) или да се трансформише у други елемент (алфа-распад, бета-распад, К-захват).
== Историја ==
<!--1895 William Roentgen discovers X-rays (1901 Nobel Prize in Physics).
1896 Henry Becquerel discovers natural radioactivity of uranium (1903 Nobel Prize in physics).
1898 Pierre and Marie Curie discover polonium and radium (1903 Nobel Prize in physics).
1911 George Hevesy uses radioactive lead as a tracer to proof left-over food being recycled into his meals (the Father of Nuclear Medicine).
1923 George Hevesy demonstrates the distribution of radioactive lead in growing bean plants (1943 Nobel Prize in chemistry).
1931 Earnest Lawrence at the University of California, Berkeley invents the cyclotron.
1934 Irene and Frederic Joliot- Curie produce the first artificial radioisotopes (1934 Nobel Prize in physics).
1935 Earnest Lawrence produces radioactive isotopes of sodium by using his new cyclotron. Over the next few years he manufactures another 17 biologically useful radioisotopes.
1939 Joseph Hamilton uses iodine-131 for diagnostic purposes in patients.
1942 The first nuclear reactor is constructed and operated at Oak Ridge National Laboratory (the Manhattan Project).
1946 Radioisotopes produced from the above nuclear reactor become available for research.
1951 Benedict Cassen at the University of California, Los Angeles invents the scintiscanner for the measurement of radioiodine in the body (the first step toward PET).
1958 Hal Anger develops the Anger Camera, which permitted visualization of radiotracer distribution in biological systems.
1975 A former Golden Gloves boxer Michael Phelps and Edward Hoffman in Ter-Pogossian's laboratory develop PETT (Positron Emission Transaxial Tomography).
In the history of radiochemistry it is possible to distinguish
few periods.1 The first period of radiochemistry formation as
an independent scientific direction, was closely related with
the discovery of new radioactive elements, understanding of
the main laws of radioactive substance behavior.
During the second period (40−50-th years) the radiochemical
investigations were focused on the practical utilization of
nuclear energy, studying of the chemical properties of artificially
obtained elements, development of technology of processing
of the irradiated nuclear fuel, resolving of the problem
of radioactive wastes burial.
The intensive development of activation analysis in the 50-
th years was also definitely stimulated by needs in qualitatively
new materials for nuclear technology (high pure carbon, beryllium,
zirconium and others ). Comparatively with known at
that time analytical methods, only NAA due to its high sensitivity
was suitable for impurities control in course of technology
development.
In the 60−70-th the serious attention was paid to the analysis
of different semi-conductors (silicon, germanium, gallium
arsenide, tellurium, cadmium telluride and other substances),
geological materials.
Later years the method begins widely to be applied for the
analysis of environmental samples, for investigations in
medicine and biology. Therefore, one can trace the similar
tendencies in priorities like in the case of radiochemistry: the
exclusive work for purposes of nuclear technology is replaced
by maintenance of diverse needs of the society.
From the 60-th the society step by step began realize the
global character of consequences of the contemporary activity
of mankind. The main attention shifted to the problems of
maintenance of the sustainable development, including such
aspects as: remediation of the polluted territories, study of the
radionuclides behavior in nature, reduction of the amount of
unavoidable (for the current nuclear technology) radioactive
wastes, development of technology of long-term radioactive
wastes storage and many other things.
Today radioactive isotopes are less often used for the elements
determination, but they find more and more wide application
in medicine, environmental science, biology for the
purposes of diagnostics, elements speciation and migration,
studying of fine biochemical processes.
-->
==Врсте радиоактивног распада==
Основне врсте радиоактивног распада су:
*α-распад - емисија језгра хелијума,
*β-распад - емисије електрона или позитрона,
*захват електрона (К захват) - захват [[електрон|електрона]] из К љуске при чему [[протон]] из језгра прелази у [[неутрон]] уз ослобађање [[неутрино|неутрина]].
*γ-распад - емисија фотона високе енергије.
<!--Ово мислим да није тачно. С. Мац([[Спонтана фисија]] језгра такође се може сматрати врстом радиоактивног распада, с обзиром да се по истим законима)-->
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