Search

Knowledge of the 3He(3He,2p)4He reaction is important for understanding stellar burning and solar neutrino production. Previous measurements have found a surprisingly large rise in the cross section at low energies that could be due to a low energy resonance in the 3He+3He (6Be) system or electron screening. In the 6Be nucleus, however, no excited states have been observed above the first 2+ state at Ex = 1.67 MeV up to 23 MeV, even though several are expected. The d(7Be,t)6Be reaction has been studied for the first time to search for resonances in the 6Be nucleus that may affect our understanding of the 3He(3He,2p)4He reaction. A 100-MeV 7Be beam from the Holifield Radioactive Ion Beam Facility (HRIBF) was used to bombard CD2 targets, and tritons were detected by the Silicon Detector Array (SIDAR). It appears that a combination of reaction mechanisms is necessary to explain the observed triton energy spectrum. [ABSTRACT FROM AUTHOR]

Two N=51 isotones have been measured using (d,p) reactions in inverse kinematics at the Holifield Radioactive Beam Facility (HRIBF) of Oak Ridge National Laboratory. Additionally, we have performed a test measurement using a stable 124Sn beam in preparation for measurements of the 2H(130,132Sn,p)131,133Sn reactions. Preliminary results for 83Ge and 85Se suggest a 5/2+ ground state and a 1/2+ first excited state for both isotopes, in agreement with systematics for the N=51 isotones. The excitation energy of the first excited state is shown to drop as the proton number is reduced. Proton angular distributions following the 2H(124Sn,p)125Sn reaction show sensitivity to the l-value of the transferred nucleon and spectroscopic factors are in agreement with previous measurements in normal kinematics. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Production of the radioisotope [sup 18]F in novae is severely constrained by the rate of the [sup 18]SF(p, α)[sup 15]O reaction. A resonance at E[sub c.m.] = 330 keV may strongly enhance the [sup 18]F(p,α)[sup 15]O reaction rate, but its strength has been very uncertain. We have determined the strength of this important resonance by measuring the [sup 18]F(p,α)[sup 15]O cross section on- and off-resonance using a radioactive [sup 18]F beam at the ORNL Holifield Radioactive Ion Beam Facility. We find that its resonance strength is 1.48±0.46 eV, and that it dominates the [sup 18]F(p, α)[sup 15]O reaction rate over a wide range of temperatures characteristic of novae. [ABSTRACT FROM AUTHOR]