Beta-decay energies

The nuclide SP was found by Lindner in the spallation products of chlorine bombarded by high energy protons and by Turkevich and Samuels in neutron irradiated quartz. The beta decay energy is found to be about 100 keV, and the lifetime about 700 years. This locates the lowest T — 2 level of at an excitation of 11.23 MeV. The decay is probably to the ground state of P transition... 

Beta-decay energies. The P-decay energies also indicate very clearly the effect of magic... 

Tritium (H-3) and carbon-14 (C-14) are also volatile radionuclides but H-3 has a short half-life (12.3 yr) and its low beta decay energy (18.5 keV) makes it a relatively mild... 

Beryllium difiuoride, dipole in, 293 Berzelius, Jons, 30 Bessemer converter, 404 Beta decay, 417 Bela particle, 417 Bicarbonate ion, 184 Bidentaie. 395 Billiard ball analogy, 6, 18 and kinetic energy, 114 Billiard ball collision, conservation of energy in, 114 Binding energy, 121, 418 Biochemistry, 421 Bismuth, oxidation numbers, 414 Blast furnace, 404 Bohr, Niels, 259 Boiling point, 67 elevation, 325 normal, 68... 

Ra decays by low energy beta decay to the short-lived Ac (with a... 

In the last decade, neutrino experiments have demonstrated that neutrinos are massive particles which may oscillate among three autostates. Such experiments [77-82] have evidenced the mass difference between the autostates, but not the neutrino mass scale value. The only way to determine the neutrino mass is the knowledge of the shape of the end point of energy spectrum in beta decays. In the hypothesis of the Majorana neutrino (neutrino coincides with antineutrino and its rest mass is different from zero), the measure of the decay half-life in the neutrinoless double-beta decay (DBD) would be necessary. A number of recent theoretical interpretations of neutrino oscillation experiments data imply that the effective Majorana mass of the electron neutrino (as measured in neutrinoless DBD) could be in the range 0.01 eV to the present bounds. 

Americium does not exist in nature. All of its isotopes are man-made and radioactive. Americium-241 is produced by bombarding plutonium-239 with high-energy neutrons, resulting in the isotope plutonium-240 that again is bombarded with neutrons and results in the formation of plutonium-241, which in turn finally decays into americium-241 by the process of beta decay. Both americium-241 and americium-243 are produced within nuclear reactors. The reaction is as follows Pu + (neutron and X gamma rays) —> " Pu + (neutron and X gamma rays) —> Pu—> Am + beta minus ([ -) followed by " Am—> jNp-237 + Hej (helium nuclei). 

The values In parentheses are the decay energies for the beta particles. 

One of the fascinating features of fission power is the breeding of fission fuel from nonfissionable uranium-238. Breeding occurs when small amounts of fissionable isotopes are mixed with uranium-238 in a reactor. Fission liberates neutrons that convert the relatively abundant nonfissionable uranium-238 to uranium-239, which beta-decays to neptunium-239, which in turn beta-decays to fissionable plutonium-239. So in addition to the abundant energy produced, fission fuel is bred from relatively abundant uranium-238 in the process. 

Any of the foregoing conditions may be achieved when the nucleus contains an even number of both protons and neutrons, or an even number of one and ail odd number of the oilier. Since Ihere is an excess of neutrons over protons for all but the lowest atomic number elements, in the odd-odd situation there is a deficiency of protons necessary to complete the two-proton-two-neutron quartets. It might be expected that these could be provided by the production of protons via beta decay. However, there exist only four stable nuclei of odd-odd composition, whereas there are 108 such nuclei in the even-odd form and 162 in the even-even series. It will be seen that the order of stability, and presumably the binding energy per nucleon, from greatest to smallest, seems to be even-even, even-odd, odd-odd. 

Another kind of particle and another kind of interaction were discovered from a detailed study of beta radioactivity in which electrons with a continuous spectrum of energies are emitted by an unstable nucleus. The corresponding interactions could be viewed as being due to the virtual transmutation of a neutron into a proton, an electron, and a new neutral particle of vanishing mass called the neutrino. The theory provided such a successful systematization of beta decay rate data for several nuclei that the existence of the neutrino was well established more than 20 years before its experimental discovery. The beta decay interaction was very weak even compared to the electron-photon interaction. 

Thus, in order to understand such environments it is necessary to calculate complete network of the competitions between neutron capture and beta decay as well as their corrections for the thermal population of excited states. With regard to this latter correction it is particularly important to know the low-energy level structure of nuclei away from stability. This structure will affect the beta decay properties differently from the neutron capture properties. In a separate contribution to this conference, [TAK85] we will discuss the corrections for beta decay. Basically this becomes important if a low-lying excited state can undergo a Gamow-Teller allowed decay. The... 

The fluctuations in neutron peak intensities arise from the Porter-Thomas distributed beta decay widths to levels in the NE nuclide. In the simplest case only a single state in the GC nuclide can be fed and only one neutron partial wave is significant. The observed levels will be a subset of levels in the NE nuclide and will be distributed in energy following a Wigner distribution. In a typical GC nuclide, however, there will be a number of accessible final states and the delayed neutron spectrum will be a superposition of transitions from several parts of the NE nuclide level structure. 

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