45 research outputs found
Far From \u27Easy\u27 Spectroscopy with the 8π and GRIFFIN Spectrometers at TRIUMF-ISAC
The 8π spectrometer, installed at the TRIUMF-ISAC facility, was the world\u27s most sensitive γ-ray spectrometer dedicated to β-decay studies. A description is given of the 8π spectrometer and its auxiliary detectors including the plastic scintillator array SCEPTAR used for β-particle tagging and the Si(Li) array PACES for conversion electron measurements, its moving tape collector, and its data acquisition system. The recent investigation of the decay of 124Cs to study the nuclear structure of 124Xe, and how the β-decay measurements complemented previous Coulomb excitation studies, is highlighted, including the extraction of the deformation parameters for the excited 0+ bands in 124Xe. As a by-product, the decay scheme of the (7+) 124Cs isomeric state, for which the data from the PACES detectors were vital, was studied. Finally, a description of the new GRIFFIN spectrometer, which uses the same auxiliary detectors as the 8π spectrometer, is given
Half-lives of neutron-rich Cd 128-130
R. Dunlop et al. ; 6 págs.; 7 figs.; 1 tab. ; Rapid CommunicationsThe β-decay half-lives of Cd128-130 have been measured with the newly commissioned GRIFFIN γ-ray spectrometer at the TRIUMF-ISAC facility. The time structures of the most intense γ rays emitted following the β decay were used to determine the half-lives of Cd128 and Cd130 to be T1/2=246.2(21) ms and T1/2=126(4) ms, respectively. The half-lives of the 3/2+ and 11/2- states of Cd129 were measured to be T1/2(3/2+)=157(8) ms and T1/2(11/2-)=147(3) ms. The half-lives of the Cd isotopes around the N=82 shell closure are an important ingredient in astrophysical simulations to derive the magnitude of the second r-process abundance peak in the A∼130 region. Our new results are compared with recent literature values and theoretical calculations. ©2016 American Physical SocietyThis work has been partially supported by the Natural Sciences
and Engineering Research Council of Canada (NSERC)
and the Canada Research Chairs Program. I.D. and R.C.-F. are
supported by NSERC Discovery Grants SAPIN-2014-00028
and RGPAS 462257-2014. A.J. acknowledges financial support
by the Spanish Ministerio de Ciencia e Innovación under
contract FPA2011-29854-C04 and the Spanish Ministerio
de Economía y Competitividad under contract FPA2014-
57196-C5-4-P. S.L.T acknowledges financial support from
the U.S. National Science Foundation under contract NSF-
14-01574. E.P.-R. acknowledges financial support from the
DGAPA-UNAM under the PASPA program. The GRIFFIN
spectrometer was funded by the Canada Foundation for
Innovation, TRIUMF, and the University of Guelph. TRIUMF
receives federal funding via a contribution agreement with the
National Research Council of Canada.Peer Reviewe
The GRIFFIN facility for Decay-Spectroscopy studies at TRIUMF-ISAC
Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei, GRIFFIN, is a new high-efficiency γ-ray spectrometer designed for use in decay spectroscopy experiments with low-energy radioactive ion beams provided by TRIUMF\u27s Isotope Separator and Accelerator (ISAC-I) facility. GRIFFIN is composed of sixteen Compton-suppressed large-volume clover-type high-purity germanium (HPGe) γ-ray detectors combined with a suite of ancillary detection systems and coupled to a custom digital data acquisition system. The infrastructure and detectors of the spectrometer as well as the performance characteristics and the analysis techniques applied to the experimental data are described
Decay spectroscopy of Cd-129
Excited states of In populated following the -decay of
Cd were experimentally studied with the GRIFFIN spectrometer at the
ISAC facility of TRIUMF, Canada. A 480-MeV proton beam was impinged on a
uranium carbide target and Cd was extracted using the Ion Guide Laser
Ion Source (IG-LIS). - and -rays following the decay of
Cd were detected with the GRIFFIN spectrometer comprising the plastic
scintillator SCEPTAR and 16 high-purity germanium (HPGe) clover-type detectors.
%, along with the -particles were detected with SCEPTAR. From the
-- coincidence analysis, 32 new transitions and 7 new
excited states were established, expanding the previously known level scheme of
In. The values deduced from the -feeding intensities
suggest that some of the high-lying states were populated by the allowed Gamow-Teller (GT) transition, which
indicates that the allowed GT transition is more dominant in the Cd
decay than previously reported. Observation of fragmented Gamow-Teller
strengths is consistent with theoretical calculations.Comment: 13 pages, 9 figures, to be published in Physical Review
Far from \u27Easy\u27 Spectroscopy with the 8π and GRIFFIN Spectrometers at TRIUMF-ISAC
The 8π spectrometer, installed at the TRIUMF-ISAC facility, was the world\u27s most sensitive γ-ray spectrometer dedicated to β-decay studies. A description is given of the 8π spectrometer and its auxiliary detectors including the plastic scintillator array SCEPTAR used for β-particle tagging and the Si(Li) array PACES for conversion electron measurements, its moving tape collector, and its data acquisition system. The recent investigation of the decay of 124Cs to study the nuclear structure of 124Xe, and how the β-decay measurements complemented previous Coulomb excitation studies, is highlighted, including the extraction of the deformation parameters for the excited 0+ bands in 124Xe. As a by-product, the decay scheme of the (7+) 124Cs isomeric state, for which the data from the PACES detectors were vital, was studied. Finally, a description of the new GRIFFIN spectrometer, which uses the same auxiliary detectors as the 8π spectrometer, is given
First Evidence of Axial Shape Asymmetry and Configuration Coexistence in Zn: Suggestion for a Northern Extension of the Island of Inversion
The excited states of Zn were investigated via -ray
spectroscopy following Cu decay. By exploiting -
angular correlation analysis, the , , and states
in Zn were firmly established. The -ray branching and
mixing ratios for transitions de-exciting the , and
states were measured, allowing for the extraction of relative values.
In particular, the and transitions were
observed for the first time. The results show excellent agreement with new
microscopic large-scale shell-model calculations, and are discussed in terms of
underlying shapes, as well as the role of neutron excitations across the
gap. Enhanced axial shape asymmetry (triaxiality) is suggested to characterize
Zn in its ground state. Furthermore, an excited band with a
significantly larger softness in its shape is identified. A shore of the
``island of inversion'' appears to manifest above , previously thought as
its northern limit in the chart of the nuclides
Spectroscopic studies of neutron-rich in 129 and its β -decay daughter, Sn 129, using the GRIFFIN spectrometer
The β decay of neutron-rich In129 into Sn129 was studied using the GRIFFIN spectrometer at the ISAC facility at TRIUMF. The study observed the half-lives of the ground state and each of the β-decaying isomers. The level scheme of Sn129 has been expanded with thirty-one new γ-ray transitions and nine new excited levels, leading to a reevaluation of the β branching ratios and level spin assignments. The observation of the β decay of the (29/2+) 1911-keV isomeric state in In129 is reported for the first time, with a branching ratio of 2.0(5)%