R. DeVito

Comparison of /sup 24,25,26/Mg(p,n)/sup 24,25,26/Al cross sections with giant M1 strength. [35 MeV]

Cross sections for the /sup 24,25,26/Mg (p,n) /sup 24,25,26/A1 reaction have been measured at 35 MeV. The strengths of the larger spin-isospin-flip transitions correspond surprisingly well with the matrix elements of the analogous giant M1 transitions.

The 26Mg(p, n)26Al reaction and the energy dependence of the spin-isospin effective interaction☆

Abstract Cross section for the 26 Mg(p, n) 26 Al reaction leading to the isobaric analog state and to low-lying 1 + , T = 0 states have been measured at bombarding energies of 24.6, 35.0 and 45.0 MeV. Several different approaches have been used to obtain values of the spin-flip ( V στ ) and no spin-flip ( V τ ) parts of the effective interactions. The ratio V στ / V τ increases with increasing energy between 25 and 45 MeV. Extracted values of V στ are somewhat larger than those obtained from lighter nuclei.

Neutron scattering from 208Pb at 30.4 and 40.0 MeV and isospin dependence of the nucleon optical potential

Analysis of data involving nuclei far from stability often requires optical potential (OP) for neutron scattering. Since neutron data is seldom available, while proton scattering data is more abundant, it is useful to have estimates of the difference of the neutron and proton optical potentials. This information is contained in the isospin dependence of the nucleon OP. Here we attempt to provide it for the nucleon-208Pb system. The goal of this paper is to obtain accurate n+208Pb scattering data, and use it, together with existing p+208Pb and 208Pb(p,n)208

Techniques for measuring neutron scattering cross sections with a beam swinger

Bi*_{IAS} data, to obtain an accurate estimate of the isospin dependence of the nucleon OP at energies in the 30-60 MeV range. Cross sections for n+208Pb scattering were measured at 30.4 and 40.0 MeV, with a typical relative (normalization) accuracy of 2-4% (3%). An angular range of 15 to 130 degrees was covered using the beam-swinger time of flight system at Michigan State University. These data were analyzed by a consistent optical model study of the neutron data and of elastic p+208Pb scattering at 45 MeV and 54 MeV. These results were combined with a coupled-channel analysis of the 208Pb(p,n) reaction at 45 MeV, exciting the 0^+ isobaric analog state in 208Bi. The new data and analysis give an accurate estimate the isospin impurity of the nucleon-208Pb OP at 30.4 MeV, caused by the Coulomb correction to the proton OP. The corrections to the real proton OP given by the CH89 global systematics was found to be only few percent, while for the imaginary potential it was over 20% at the nuclear surface. Based on the analysis of the measured elastic p+208Pb data at 40 MeV, a Coulomb correction of similar strength and shape was also predicted for the p+208Pb OP at energy around 54 MeV.

Q-value systematics for isovector giant resonances excited by (p,n) reactions on Zr, Nb, Mo, Sn, and Pb isotopes

Abstract Techniques have been developed for measuring neutron elastic and inelastic scattering cross sections using a beam swinger based time-of-flight system. The use of a beam swinger has significant advantages at high neutron energies because of the simplification of shielding arrangements and the convenient use of long flight paths to obtain high resolution. Applications have been made to neutron scattering at 30.3 and 40 MeV.