25 research outputs found
An experimental study of the rearrangements of valence protons and neutrons amongst single-particle orbits during double {\beta} decay in 100Mo
The rearrangements of protons and neutrons amongst the valence
single-particle orbitals during double {\beta} decay of 100Mo have been
determined by measuring cross sections in (d,p), (p,d), (3He,{\alpha}) and
(3He,d) reactions on 98,100Mo and 100,102Ru targets. The deduced nucleon
occupancies reveal significant discrepancies when compared with theoretical
calculations; the same calculations have previously been used to determine the
nuclear matrix element associated with the decay probability of double {\beta}
decay of the 100Mo system.Comment: 18 pages, 13 figures, 37 pages of supplemental informatio
Change of nuclear configurations in the neutrinoless double- decay of Te Xe and Xe Ba
The change in the configuration of valence protons between the initial and
final states in the neutrinoless double- decay of Te
Xe and of Xe Ba has been
determined by measuring the cross sections of the (,He) reaction with
101-MeV deuterons. Together with our recent determination of the relevant
neutron configurations involved in the process, a quantitative comparison with
the latest shell-model and interacting-boson-model calculations reveals
significant discrepancies. These are the same calculations used to determine
the nuclear matrix elements governing the rate of neutrinoless double-
decay in these systems.Comment: 10 pages, 4 figures, 9 table
Neutron occupancies and single-particle energies across the stable tin isotopes
The occupancies and vacancies of the valence neutron orbitals across the
stable tin isotopic chain from have been determined. These
were inferred from the cross sections of neutron-adding and -removing
reactions. In each case, the reactions were chosen to have good
angular-momentum matching for transfer to the low- and high- orbitals
present in this valence space. These new data are compared to older systematic
studies. The effective single-neutron energies are determined by combining
information from energy centroids determined from the adding and removing
reactions. Two of the five orbitals are nearly degenerate, below , and
approximately two MeV more bound than the other three, which are also
degenerate.Comment: 11 pages, 10 figure
Experimental study of the rearrangements of valence protons and neutrons amongst single-particle orbits during double-ÎČ decay in 100Mo
The rearrangements of protons and neutrons amongst the valence single-particle orbitals during double-ÎČ decay of Mo100 have been determined by measuring cross sections in (d,p), (p,d), (He3,α), and (He3,d) reactions on Mo98,100 and Ru100,102 targets. The deduced nucleon occupancies reveal significant discrepancies when compared with theoretical calculations; the same calculations have previously been used to determine the nuclear matrix element associated with the decay probability of double-ÎČ decay of the Mo100 system.This material is based upon work supported by the UK Science and Technology Facilities Council, the US
Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357, the National Science Foundation Grant No. PHY-08022648 (JINA), and the Deutsche Forschungsgemeinschaft Cluster of Excellence âOrigin and Structure of the Universe.
Lifetime measurements of excited states in Âčâ¶ÂłW and the implications for the anomalous B(E2) ratios in transitional nuclei
This letter reports lifetime measurements of excited states in the odd-N nucleus 163W using the recoil-distance Doppler shift method to probe the core polarising effect of the i13/2 neutron orbital on the underlying soft triaxial even-even core. The ratio B(E2:21/2âș â 17/2âș)/B(E2:17/2âș â 13/2âș) is consistent with the predictions of the collective rotational model. The deduced B(E2) values provide insights into the validity of collective model predictions for heavy transitional nuclei and a geometric origin for the anomalous B(E2) ratios observed in nearby even-even nuclei is proposed
Decay spectroscopy at the two-proton drip line: radioactivity of the new nuclides 160Os and 156W
The radioactivity of 76160Os84 and 74156W82 that lie at the two-proton drip line have been measured in an experiment performed at the Accelerator Laboratory of the University of JyvĂ€skylĂ€. The 160Os nuclei were produced using fusion-evaporation reactions induced by a beam of 310 MeV 58Ni ions bombarding a 106Cd target. The 160Os ions were separated in flight using the recoil separator MARA and implanted into a double-sided silicon strip detector, which was used to measure their decays. The α decays of the ground state of 160Os (Eα = 7092(15) keV, t1/2 = 97â32+97 ÎŒs) and its isomeric state (Eα = 8890(10) keV, t1/2 = 41â9+15 ÎŒs) were measured, allowing the excitation energy of the isomer to be determined as 1844(18) keV. These α-decay properties and the excitation energy of the isomer are compared with systematics. The α decays were correlated with subsequent decays to investigate the ÎČ decays of the ground state of 156W, revealing that unlike its isotones, both low-lying isomers were populated in its daughter nuclide, 156Ta. An improved value for the half-life of the proton-decaying high-spin isomeric state in 73156Ta83 of 333â22+25 ms was obtained in a separate experiment using the same experimental systems with a 102Pd target. This result was employed to improve the precision of the half-life determined for 156W, which was measured as 157â34+57 ms