20 research outputs found
Measurement of alphaâwidths in 16O relevant to astrophysics
Several different αâtransfer reactions, 12Câ16O, have been studied at high bombarding energies with magnetic spectrometers. Lineâwidths, αâspectroscopic factors, Sα, and reduced αâwidths, γα2 and Ïα2, have been determined for levels in 16O, including several of importance in astrophysics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87457/2/752_1.pd
Reaction dependence of nuclear decay linewidths
Various light- and heavy-ion reactions, 20 E 8Be*(2 + , 2.9 MeV) and 16O*(1-, 9.6 MeV). Although slight differences (R) are self-consistent and indicate little if any reaction dependence (R by 20 % or more, however, and thus care must be taken in comparing decay widths inferred from nuclear reactions with those from scattering resonances. Reduced formal [alpha]-decay widths of [gamma][lambda]2 = 680 +/- 100 keV (s = 4.8 fm) and [gamma][lambda]2 = 350 +/- 50 keV(s = 5.4 fm), corresponding to [theta][lambda]2 = 0.50 and [theta][lambda]2 = 0.49 are deduced for 8Be*(2 + , 2.9 MeV) and 16O*(1-, 9.6 MeV) using the nuclear-reaction [Gamma]R values and a particular set of [alpha]-nucleus potentials.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24278/1/0000544.pd
Two-proton events in the 17F(p,2p)16O reaction
In a recent experimental study (Gomez del Campo et al, PRL 86, 43 (2001)) of
the reaction 17F(p,2p)16O, two-proton events were measured from excitations
near a 1-, E*=6.15 MeV state in 18Ne. We calculate by means of R-matrix theory
the resonant two-proton production cross section and branching ratios. We
conclude that it is unlikely that two-proton production via population of the
1- state is sufficient to explain the observed two-proton events. Alternative
sources of such events are discussed.Comment: 4 pages, 4 figures. Resubmission to Physical Review C (first received
6 March 2001
An above-barrier narrow resonance in <sup>15</sup>F
Intense and purified radioactive beam of post-accelerated O was used
to study the low-lying states in the unbound F nucleus. Exploiting
resonant elastic scattering in inverse kinematics with a thick target, the
second excited state, a resonance at E=4.757(6)(10)~MeV with a width of
=36(5)(14)~keV was measured for the first time with high precision. The
structure of this narrow above-barrier state in a nucleus located two neutrons
beyond the proton drip line was investigated using the Gamow Shell Model in the
coupled channel representation with a C core and three valence protons.
It is found that it is an almost pure wave function of two quasi-bound protons
in the shell.Comment: 8 pages, 2 figures, 1 table, Submitted to Phys. Lett.
24Mg(α,12C)16O at Eα=90 MeV
The reaction 24Mg(α,12C)16O has been studied at Eα=90 MeV and exhibits characteristics suggestive of a directâtype reaction, either 8Be transfer or successive αâtransfer.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87454/2/728_1.pd