Search results for "ISOTOPES"

Study of the Ti44(α,p)V47 reaction and implications for core collapse supernovae

2014

The underlying physics triggering core collapse supernovae is not fully understood but observations of material ejected during such events helps to solve this puzzle. In particular, several satellite based γ-ray observations of the isotope 44Ti have been reported recently. Conveniently, the amount of this isotope in stellar ejecta is thought to depend critically on the explosion mechanism. The most influential reaction to the amount of 44Ti in supernovae is Ti44(α,p)V47. Here we report on a direct study of this reaction conducted at the REX-ISOLDE facility, CERN. The experiment was performed with a 44Ti beam at Elab = 2.16MeV/u, corresponding to an energy distribution, for reacting α-partic…

Gamow-Teller Transitions and β-decay Half-life in Proton Rich pf-shell Nuclei

2010

In violent neutrino‐induced reactions at the core‐collapse stage of type II supernovae, Gamow‐Teller (GT) transitions starting from stable as well as unstable pf‐shell nuclei play important roles. In the β‐decay study of these unstable pf‐shell nuclei, half‐lives can be measured rather accurately. On the other hand, in high‐resolution (3He,t) charge‐exchange reactions at 0°, individual GT transitions up to high excitations can be studied. Assuming the isospin symmetry for the strengths of Tz = ±2→±1 analogous GT transitions, we present a “merged analysis” for the determination of GT transition strengths starting from proton‐rich Tz = −2 nuclei. We applied this analysis to the A = 52, T = 2 …

High Resolution Λ Hypernuclear Spectroscopy with Electron Beams

2015

T. Gogami1 ∗, P. Achenbach2, A. Ahmidouch3, I. Albayrak4, D. Androic5, A. Asaturyan6, R. Asaturyan6, O. Ates4, P. Baturin7, R. Badui7, W. Boeglin7, J. Bono7, E. Brash8, P. Carter8, C. Chen4, A. Chiba1, E. Christy4, S. Danagoulian3, R. De Leo10, D. Doi1, M. Elaasar11, R. Ent9, Y. Fujii1, M. Fujita1, M. Furic5, M. Gabrielyan7, L. Gan12, F. Garibaldi13, D. Gaskell9, A. Gasparian3, O. Hashimoto1, T. Horn9, B. Hu14, Ed. V. Hungerford21, M. Jones9, H. Kanda1, M. Kaneta1, S. Kato19, M. Kawai1, D. Kawama1, H. Khanal7, M. Kohl4, A. Liyanage4, W. Luo14, K. Maeda1, A. Margaryan6, P. Markowitz7, T. Maruta1, A. Matsumura1, V. Maxwell7, A. Mkrtchyan6, H. Mkrtchyan6, S. Nagao1, S. N. Nakamura1, A. Narayan…

Nuclear Shape Staggering in Very Neutron-Deficient Hg Isotopes Detected by Laser Spectroscopy

1977

The isotope shifts of $^{188}\mathrm{Hg}$, $^{186}\mathrm{Hg}$, and $^{184}\mathrm{Hg}$ in the 2537-\AA{} line have been measured by use of tunable dye laser at the on-line mass separator ISOLDE at CERN. The results are $\ensuremath{\delta}\ensuremath{\nu}(^{188}\mathrm{Hg}\ensuremath{-}^{204}\mathrm{Hg})=35.8(2)$ GHz; $\ensuremath{\delta}\ensuremath{\nu}(^{186}\mathrm{Hg}\ensuremath{-}^{204}\mathrm{Hg})=39.4(2)$ GHz; and $\ensuremath{\delta}\ensuremath{\nu}(^{184}\mathrm{Hg}\ensuremath{-}^{204}\mathrm{Hg})=43.1(2)$ GHz. These data combined with those obtained by $\ensuremath{\beta}$-radiation-detected optical pumping ($\ensuremath{\beta}$-RADOP) on the odd Hg isotopes yield a huge odd-even…

Note on the decay of200Au

1972

Gamma and beta rays from the decay of200Au (48.4 min) were studied employing Ge(Li) and plastic detectors in various singles and coincidence arrangements. The intensity of the β-branch to the ground state of200Hg was determined as 79%, and the disintegration energy of200Au to be asQβ=2.26 ± 0.06 MeV. A tentative spin and parity assignment of (1,2)+ is proposed for levels at 1515.2 and 1972.5 keV in 200Hg

R-matrix analysis of theβdecays ofN12andB12

2010

The β decays of 12N and 12B have been studied at KVI and JYFL to resolve the composition of the broad and interfering 0+ and 2+ strengths in the triple-α continuum. For the first time a complete treatment of 3α decay is presented including all major breakup channels. A multilevel, many-channel R-matrix formalism has been developed for the complete description of the breakup in combination with the recently published separate analysis of angular correlations. We find that, in addition to the Hoyle state at 7.65 MeV, more than one 0+ and 2+ state is needed to reproduce the spectra. Broad 03+ and 22+ states are found between 10.5 and 12 MeV in this work. The presence of β strength up to the 12…

High-precision mass measurement ofS31with the double Penning trap JYFLTRAP improves the mass value forCl32

2010

Mass mapping of a new area of neutron-deficient suburanium nuclides

2002

Abstract The masses of 64 short-lived neutron-deficient nuclides covering the element range from tungsten to uranium have been obtained for the first time. They have been evaluated by combining directly measured masses from Schottky mass spectrometry with linked experimental Q-values in α-decay chains. Based on these new mass data we have determined the one-proton and two-proton drip-lines as well as the size of the “littoral shallow” of the sea of instability. No evidence of a Thomas–Ehrman shift has been found in the region of the investigated heavy nuclides. A peculiar behavior of two-proton separation energies has been observed in the lead region. The predictive power of various mass mo…

Structure of exotic 7He and 9He

2004

The heavy helium isotopes 7,9 He were studied via their isobaric analog states (IAS) in 7,9 Li. The IAS were populated via resonance reactions of protons with radioactive beams of 6,8 He. The isospin-conserving neutron decay of T=3/2 resonances in 7 Li and proton decay of T=5/2 resonances in 9 Li were measured. New spectroscopic information on these states were obtained, and compared with the properties of levels in 7,9 He.

Systematics of Gamow-Teller beta decay “Southeast” of 100Sn

2010

The energy centroids and integrated strengths of Gamow-Teller transitions in the $ \beta^{+}_{}$ and electron-capture decay are analyzed for nuclei whose proton number Z and neutron number N are restricted to 44 $ \leq$ Z $ \leq$ 50 and 50 $ \leq$ N $ \leq$ 58 . The analysis is based on data measured both with high-resolution $ \gamma$ -ray spectrometry and total $ \gamma$ -ray absorption techniques. The dependence of the considered quantities on the relative neutron excess are established after taking into account the effects due to the Coulomb interaction and mean-field level occupancies. An extrapolation of this dependence to the lightest known tin isotopes is used to estimate the decay …