Energy of nuclear reactions

Some isotopes used in PET scans are carbon-11, nitrogen-13, oxygen-15, and fluorine-18. All have short half-lives, so the radiation dosage to the patient is minimal. However, because of the short half-life, a chemist must pre- 

The scans are of the brains of a normal patient and a schizophrenic patient.The scans show differences in brain activities measured by glucose usages—yellow-to-red colors show high values green-to-blue are low values. 

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Niobium is used primarily in making alloys. For example, the addition of niobium to steel greatly increases its strength. One use of such steel is in the construction of nuclear reactors. Nuclear reactors are devices in which the energy of nuclear reactions is converted to electricity. Niobium steel is used because it keeps its strength at the very high temperatures produced there. 

The energies of nuclear reactions and radioactive decays can only be considered with the aid of Einstein s equation relating mass and energy ... 

The recoil energy of nuclear reactions producing inert gases can be used for the implantation of gases into solid samples. Some of the nuclear reactions which have been used for the production of inert gas atoms and their introduction into solid samples are listed in Table 1. 

The energy of nuclear reactions, AE, calculated from the difference between the masses of products and reactants in accordance with the Einstein law (page 69), is in agreement with the measured values. For the transmutation of radium, Equation (1), the masses (g/mole) of... 

H. A. Bethe (Cornell) contributions to the theory of nuclear reactions, especially discoveries concerning the energy production in stars. 

Fermi had been fascinated by the discovery of the neutron by James Chadwick in 1932. He gradually switched his research interests to the use of neutrons to produce new types of nuclear reactions, in the hope of discovering new chemical elements or new isotopes of known elements. He had seen at once that the uncharged neutron would not be repelled by the positively-charged atomic nucleus. For that reason the uncharged neutron could penetrate much closer to a nucleus without the need for high-energy particle accelerators. lie discovered that slow neutrons could... 

Energy can be neither created nor destroyed (in the absence of nuclear reactions). 

The first major set of nuclear reactions in stellar evolution involves hydrogenburning through the pp chains and the CN cycle or CNO bi-cycle, which liberate 6.68 MeV of energy per proton minus neutrino losses (2 neutrinos are emitted for each 4He nucleus synthesized). The first two reactions of the pp chains are... 

A critical point in the retrieving of the number of nuclear reactions in laser-solid experiments is that there is no control on the spectrum of the electrons accelerated in the interaction, as well as the acceleration mechanism is uncertain and difficult to fit in a predictable scheme. In most cases, the electron energy distribution is assumed to be Boltzmann-like and deconvolutions are performed starting from this assumption. 

Although many other types of nuclear reaction are possible as a result of high neutron fluxes, these two are the ones of prime importance in radioanalytical chemistry. The two principal requirements for a reaction to be useful analytically are that the element of interest must be capable of undergoing a nuclear reaction of some sort, and the product of that reaction (the daughter) must itself be radioactively unstable. Ideally, the daughter nucleus should have a half life which is in the range of a few days to a few months, and should emit a particle which has a characteristic energy, and is free from interference from other particles which may be produced by other elements within the sample. 

Like physical changes and chemical reactions, nuclear reactions are accompanied hy energy changes. Nuclear reactions, however, produce significantly more energy than physical and chemical processes. In nuclear reactions, a significant amount of the mass of the reactants is actually converted into energy. 

Five experiments have so far detected solar neutrinos. These are Homestake (USA), GALLEX, SAGE, KAMIOKANDE and SUPERKAMIOKANDE, all set up down mines or tunnels. Detected fluxes agree qualitatively with theoretical predictions, both in numbers and energies. We may say that we have basically understood how the Sun shines. The same set of nuclear reactions invoked to explain the solar luminosity does give rise to neutrinos. 

Q-value of Nuclear Reactions All types of nuclear reactions are accompanied by either absorption or release of energy. The amount of energy released or absorbed in a nuclear reaction is called Q-value of the nuclear reaction. Thus the following two cases arises... 

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