0000000000199456
AUTHOR
B. R. Fulton
STUDIES OF 12C USING β-DECAYS
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.
News on 12C from beta-decay studies
We discuss the importance of the spectroscopic properties of the resonances of 12C just above the 3α-threshold, and review the existing experimental information of this region with emphasis on O+ and 2+ states. A new experimental approach for studying the β-decays of 12B and 12N is presented based on techniques developed in the context of Radioactive beam (rare isotope) physics. Finally preliminary results from an ongoing analysis of two recent experiments are given. © 2004 Published by Elsevier B.V.
R-matrix analysis of theβdecays ofN12andB12
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…
The β-decay approach for studying 12C
6 pags., 3 figs. -- 9th International Conference on Clustering Aspects of Nuclear Structure and Dynamics (CLUSTERS'07) 3–7 September 2007, Stratford upon Avon, UK
Influences on the triple alpha process beyond the Hoyle state
7 pags., 3 figs. -- International Symposium on Nuclear Astrophysics - Nuclei in the Cosmos - IX, 25-30 June 2006, CERN
Precise branching ratios to unbound 12C states from 12N and 12B β-decays
6 pages, 2 tables, 4 figures.--PACS nrs.: 21.45.-v; 23.40.-s; 27.20.+n; 21.60.De.--Printed version published Aug 3, 2009
Properties of the 12C 10 MeV state determined through β-decay
16 pages, 1 table, 10 figures.-- PACS nrs.: 23.40.-s; 26.20.+f; 27.20.+n.-- Printed version published Oct 3, 2005.
Branching ratios in theβdecays ofN12andB12
Absolute branching ratios to unbound states in C-12 populated in the beta decays of N-12 and B-12 are reported. Clean sources of N-12 and B-12 were obtained using the isotope separation on-line (ISOL) method. The relative branching ratios to the different populated states were extracted using single-alpha as well as complete kinematics triple-alpha spectra. These two largely independent methods give consistent results. Absolute normalization is achieved via the precisely known absolute branching ratio to the bound 4.44 MeV state in C-12. The extracted branching ratios to the unbound states are a factor of three more precise than previous measurements. Branching ratios in the decay of Na-20 …
Breakup channels forC12triple-αcontinuum states
The triple-alpha-particle breakup of states in the triple-alpha continuum of C-12 has been investigated by way of coincident detection of all three alpha particles of the breakup. The states have been fed in the beta decay of N-12 and B-12, and the alpha particles measured using a setup that covers all of the triple-alpha phase space. Contributions from the breakup through the Be-8(0(+)) ground state as well as other channels-interpreted as breakup through excited energies in Be-8-have been identified. Spins and parities of C-12 triple-alpha continuum states are deduced from the measured phase-space distributions for breakup through Be-8 above the ground state by comparison to a fully symme…