Nuclear transmutations

The scope of nuclear chemistry would be rather narrow if study were limited to natural radioactive elements. An experiment performed by Rutherford in 1919, however, suggested the possibility of producing radioactivity artificially. When he bombarded a sample of nitrogen with a particles, the following reaction took place  

An oxygen-17 isotope was produced with the emission of a proton. This reaction demonstrated for the first time the feasibility of converting one element into another, by the process of nuclear transmutation. Nuclear transmutation differs from radioactive decay in that transmutation is brought about by the collision of two particles. 

The preceding reaction can be abbreviated as 7N(a,p) 0. In the parentheses the bombarding particle is written first, followed by the emitted particle. Sample Problem 20.5 shows how to use this notation to represent nuclear transmutations. 

Think About It Check your work by summing the mass numbers and the atomic numbers on both sides of the equation. 

Write the balanced nuclear equation for the reaction represented by 2gFe(d,a) Mn, where d represents a deuterium nucleus. 

Sample Problem 20.5 shows how to use this notation to represent nuclear transmutations. 

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Helium-3 [14762-55-1], He, has been known as a stable isotope since the middle 1930s and it was suspected that its properties were markedly different from the common isotope, helium-4. The development of nuclear fusion devices in the 1950s yielded workable quantities of pure helium-3 as a decay product from the large tritium inventory implicit in maintaining an arsenal of fusion weapons (see Deuterium AND TRITIUM) Helium-3 is one of the very few stable materials where the only practical source is nuclear transmutation. The chronology of the isolation of the other stable isotopes of the hehum-group gases has been summarized (4). 

Nuclear activation analysis (NAA) is a method for qualitatively and quantitatively detg elemental compn by means of nuclear transmutations. The method involves the irradiation or bombardment of samples with nuclear particles or high-energy electromagnetic radiation for the specific purpose of creating radioactive isotopes from the stable or naturally-occurring elements present. From the numbers, types and quantities of radioactive elements or radionuclides, it is possible to deduce information about the elemental compn of the original sample... 

Fig. 17.7), is therefore the nucleus of an atom of a different element. For example, when a radon-222 nucleus emits an a particle, a polonium-218 nucleus is formed. In this case, a nuclear transmutation, the conversion of one element into another, has taken place. Another important difference between nuclear and chemical reactions is that energy changes are very much greater for nuclear reactions than for chemical reactions. For example, the combustion of 1.0 g of methane produces about 52 kj of energy as heat. In contrast, a nuclear reaction of 1.0 g of uranium-235 produces about 8.2 X 10 kj of energy, more than a million times as much. 

In the year 2000, 15% of the world s electric power was produced by 433 nuclear power reactors 169 located in Europe, 120 in the United States, and 90 in the Far East. These reactors consumed 6,400 tons of fresh enriched uranium that was obtained through the production of 35,000 tons of pure natural uranium in 23 different nations the main purification step was solvent extraction. In the reactors, the nuclear transmutation process yielded fission products and actinides (about 1000 tons of Pu) equivalent to the amount of uranium consumed, and heat that powered steam-driven turbines to produce 2,400 TWh of electricity in 2000. 

Einsteinium does not exist in nature and is not found in the Earth s crust. It is produced in small amounts by artificial nuclear transmutations of other radioactive elements rather than by additional explosions of thermonuclear weapons. The formation of einsteinium from decay processes of other radioactive elements starts with plutonium and proceeds in five steps as follows ... 

Neutrinos inform us almost instantaneously of what is happening in the Sun s core. However, the main interest of this solar cardiograph is hardly to detect some failure in the Sun s cycle. In capturing solar neutrinos, the aim of contemporary physics is rather to catch the Sun in the act of nuclear transmutation. By measuring the neutrino flux, we may check our understanding of the Sun as a whole and at the same time analyse the relationship between this strange particle and more commonplace forms of matter. 

The high abundance of hehumA is so striking that we cannot help wondering why certain heavier nuclei, more stable and better constructed, have remained so scarce. Iron is a case in point. Why does the work of nuclear transmutation have this unfinished air about it ... 

In addition to the above-mentioned features, the ion beam irradiation has functions of implantation of different atoms in the irradiated medium and of the nuclear transmutation of the irradiated medium atoms. So far, the underlying physics and the subsequent relaxation processes in the interaction between ion beams and matter have been extensively studied not only for purely scientific interests but also for practical purposes, such that a series of international conferences on these topics have been held on a worldwide scale [2]. 

B, 292-302 303-10(1951) (Penetration into a ductile target, such as lead, mild steel, etc) 35) Z. Fonberg, JChemPhys 19, 383 (195 1) (Evidence of nuclear transmutation in the course of explosion of shaped charges with lined cavity) French transln in MAF 26, 489-91(1952) 36) P. Tauzin,... 

Some noble gas components are referred to as in situ, meaning that they were produced within a given meteorite sample by nuclear transmutations. These are the nuclear... 

MUuno, T. and J. Rolhvvell Nuclear Transmutation The Reality of Cold Fusion. 

V I those with atomic numbers higher than uranium, do not occur naturally but are produced by nuclear transmutation reactions, discussed in Section 22.7. 

Only about 300 of the more than 3600 known isotopes occur naturally. The remainder have been made by nuclear transmutation, the change of one element into another. Such transmutation is often brought about by bombardment of an atom with a high-energy particle such as a proton, neutron, or a particle. In the ensuing collision between particle and atom, an unstable nucleus is momentarily... 

Other nuclear transmutations can lead to the synthesis of entirely new elements never before seen on Earth. In fact, all the transuranium elements—those elements with atomic numbers greater than 92—have been produced by bombardment reactions. Plutonium, for example, can be made by bombarding uranium-238 with a particles ... 

Still other nuclear transmutations are carried out using neutrons, protons, or other particles for bombardment. The cobalt-60 used in radiation therapy for cancer patients can be prepared by neutron bombardment of iron-58. Iron-58 first absorbs a neutron to yield iron-59, the iron-59 undergoes j8 decay to yield cobalt-59, and the cobalt-59 then absorbs a second neutron to yield cobalt-60 ... 

E. Experimental Evidence of HDCC-Rroduced Nuclear Transmutation... 

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