Search results for "decay"
showing 10 items of 2087 documents
Precise energies of gamma rays from the 230Th and 228Th decay
1977
Abstract Energies up to 300 keV of prominent gamma rays from the decay of 230 Th, 228 Th and some of the 228 Th descendants have been precisely measured by use of Ge(Li) detectors.
Competing Decay Modes of a High-spin Isomer in the Proton-unbound Nucleus $^{158}$Ta
2015
An isomeric state at high spin and excitation energy was recently observed in the proton-unbound nucleus 158Ta. This state was observed to decay by both α and γ decay modes. The large spin change r ...
Quantum Theory of a Radiating Harmonically Bound Charge
2010
A phenomenological Hamiltonian giving the equation of motion of a non relativistic charges that accelerates and radiates is quantized. The theory is applied to the harmonic oscillator. To derive the decay time the physical parameters entering the calculations are obtained from the theory of the hydrogen atom; the agree- ment of the predicted value with the experiments is striking although the mathematics is very simple.
Competition Between Beta and Double Beta Decay in 48Ca and 96Zr
2000
Highly forbidden beta decays of 48Ca and 96Zr are studied and their relative importance as compared to the double beta decay of these nuclei is evaluated. 48Ca and 96Zr are the only naturally occurring nuclei in which these processes can occur simultaneously. Although usually ordinary beta decay overwhelms double beta decay unless the former is energetically forbidden, in these cases the high degree of forbiddenness and small release of kinetic energy makes the half-lives of these modes comparable to each other.
Shell-model study of the highly forbidden beta decay 48 Ca → 48 Sc
1999
Ordinary β− decay of the 0+ ground state of 48Ca is studied. Partial half-lives for the highly-forbidden transitions to the three lowest-lying states (6+,5+,4+) of 48Sc are calculated by using both the harmonic oscillator and the Woods-Saxon mean-field wave functions. We find the decay to be dominated, as expected, by the unique fourth-forbidden transition to the excited 5+ state of 48Sc. The theoretical beta-decay half-life of 48Ca is found to be 1.1−0.6+0.8·1021 years which is approximately 25 times longer than the measured double-beta-decay half-life of T1/22ν = (4.3−1.1+2.4[stat] ± 1.4[syst])·1019 years.
Study of Basic Nuclear Properties of Highly-Charged, Unstable Nuclei at the SIS-FRS-ESR Complex
2004
Recent progress in experiments with exotic nuclear beams at the SIS-FRS-ESR facility is summarized. New results on gross properties of exotic nuclei like binding energy, half-lives, and decay modes are presented. A brief outlook to future experiments is given.
New microsecond isomers in 189, 190Bi
2001
New microsecond isomers in the neutron-deficient isotopes 189g, 190Bi have been identified after in-flight separation by the velocity filter SHIP. The evaporation residues were identified on the basis of delayed recoil-γ/X-ray, recoil-γ/X-ray-α and excitation function measurements. The systematics of the [ π1i 13/2]13/2+ excited states in the odd-mass Bi nuclei is discussed.
Beta Decay of Molecular Tritium
2020
The beta decay of tritium in the form of molecular TT is the basis of sensitive experiments to measure neutrino mass. The final-state electronic, vibrational, and rotational excitations modify the beta spectrum significantly, and are obtained from theory. We report measurements of the branching ratios to specific ionization states for the isotopolog HT. Two earlier, concordant measurements gave branching ratios of HT to the bound HHe$^+$ ion of 89.5% and 93.2%, in sharp disagreement with the theoretical prediction of 55-57%, raising concerns about the theory's reliability in neutrino mass experiments. Our result, 56.5(6)%, is compatible with the theoretical expectation and disagrees strongl…
Total absorption spectroscopy study of the β decay of Br86 and Rb91
2017
The beta decays of 86Br and 91Rb have been studied using the total absorption spectroscopy technique. The radioactive nuclei were produced at the IGISOL facility in Jyvaskyla and further purified using the JYFLTRAP. 86Br and 91Rb are considered high priority contributors to the decay heat in reactors. In addition 91Rb was used as a normalization point in direct measurements of mean gamma energies released in the beta decay of fission products by Rudstam et al. assuming that this decay was well known from high-resolution measurements. Our results shows that both decays were suffering from the Pandemonium effect and that the results of Rudstam et al. should be renormalized.
TAGS measurements of $^{100}$Nb ground and isomeric states and $^{140}$Cs for neutrino physics with the new DTAS detector
2016
V. Guadilla et al. -- 4 pags., 6 figs. -- Open Access funded by Creative Commons Atribution Licence 4.0