Search results for "nuclear structure"

STUDIES OF 12C USING β-DECAYS

2008

The nuclear structure of states in 12 C have been a subject of interest for both theory and experiment since the early days of nuclear physics. Many open questions remain, especially concerning the existence and properties of 0+ and 2+ states in the triple alpha continuum. A series of experiments have been performed using β-decay of 12 N and 12 B to probe these states. The latest experiment was performed at KVI using an implantation method, measuring the sum energy of the three α-particles directly. Preliminary results from this experiment will be presented.

Evidence for oblate structure inPb186

2005

In-beam $\ensuremath{\gamma}\ensuremath{\gamma}$ coincidence data have been collected for $^{186}\mathrm{Pb}$ by combining the JUROGAM Ge-detector array and the GREAT spectrometer with the RITU gas-filled recoil separator for recoil-decay tagging measurements. In addition to the known prolate yrast band in $^{186}\mathrm{Pb}$, these data have enabled a new low-lying side band to be identified. Based on the analysis of its decay pattern and comparison with Interacting Boson Model (IBM) calculations, the new band is associated with an oblate shape.

Estimation of bounds for left-right mixing from nuclear double beta decay processes

1993

Abstract Nuclear matrix elements, extracted from a systematic calculation of neutrinoless double beta decay rates for 0 + g.s →o + g.s transitions in 76 Ge, 82 Se, 128 Te, 130 Te and 136 Xe, have been used to compute bounds on the left-right mixing angle ζ of the weak currents. The parameters of the nuclear model have been fixed by calculating the corresponding two-neutrino double beta decay half lives. The present analysis favours a mixing of the order of |tanξ| −3 which is to be compared with those obtained in muon decay (|tan ξ | ⩽ 0.035) and in supernova (|tan ξ | ⩽ 10 −5 ) analysis. It shows that nuclear structure calculations yield estimates on ξ which complement the existing data.

Microscopic nuclear-structure calculations for the solar-neutrino detector and close-lying isobars

2003

In the present solar-neutrino experiments, mainly observing the pp contribution of the solar-neutrino flux, an important role is played by 71Ga. The structure of this detector nucleus and three of its isobars have been calculated by using the microscopic quasiparticle–phonon model. Using a realistic effective two-body interaction in a realistic valence space, the method yielded energy spectra in good agreement with experiments. The calculated logft values for a number of spontaneous and neutrino-induced Gamow–Teller transitions, when compared with the experimental results, gave qualitatively correct but overestimated transition-strength values in most cases.

On the nuclear structure of 229Ra

1992

14 pages, 3 tables, 6 figures.

TAS measurements for reactor physics and nuclear structure

2011

In this contribution we will present recent total absorption measurements of the beta decay of neutron‐rich nuclei performed at the IGISOL facility of the Univ. of Jyvaskyla. In the measurements the JYFL Penning Trap was used as a high resolution isobaric separator. The total absorption technique will be described and the impact of recent results in the fields of reactor physics (decay heat calculations) and nuclear structure will be discussed.

In-beam spectroscopy of heavy elements

2015

Abstract Traditionally the experimental study of heavy and superheavy elements has belonged to the realm of decay spectroscopy and nuclear reactions. Only in the past twenty years or so has it become feasible to study nuclei with Z = 96 and beyond with in-beam spectroscopic techniques. Since the pioneering studies in the late 1990s, development of both instrumentation and experimental techniques has resulted in a significant lowering of the spectroscopic limit for in-beam measurements. Such measurements give access to a wide range of nuclear structure observables which in general are beyond the reach of other techniques. The current review aims to present the most recent developments and re…

First observation of excited states in the very neutron deficient nucleus76165Osand the yrast structure of76166Os

2002

Thermonuclear reactionS30(p,γ)Cl31studied via Coulomb breakup ofCl31

2014

Coulomb breakup at high energy in inverse kinematics of proton-rich Cl-31 was used to constrain the thermonuclear S-30(p,gamma)Cl-31 capture reaction rate under typical Type I x-ray burst conditions. This reaction is a bottleneck during rapid proton-capture nucleosynthesis (rp process), where its rate depends predominantly on the nuclear structure of Cl-31. Two low-lying states just above the proton-separation threshold of S-p = 296( 50) keV in Cl-31 have been identified experimentally using the (RB)-B-3-LAND setup at the GSI Helmholtzzentrum fur Schwerionenforschung GmbH. Both states are considered to play a key role in the thermonuclear S-30( p,gamma)Cl-31 capture reaction. Excitation ene…

Characterization of a new modular decay total absorption gamma-ray spectrometer (DTAS) for FAIR

2013

Beta-decay studies are one of the main goals of the DEcay SPECtroscopy experiment (DESPEC) to be installed at the future Facility for Antiproton and Ion Research (FAIR). DESPEC aims at the study of nuclear structure of exotic nuclei. A new modular Decay Total Absorption gamma-ray Spectrometer (DTAS) is being built at IFIC and is specially adapted to studies at fragmentation facilities such as the Super Fragment Separator (Super-FRS) at FAIR. The designed spectrometer is composed of 16 identical NaI(Tl) scintillation crystals. This work focuses on the characterization of these independent modules, as an initial step for the characterization of the full spectrometer. Monte Carlo simulations h…