Study of theC12(d, p)C13Reaction Mechanism: Polarization and (d, pγ) Correlations

Abstract

Measurements in the deuteron energy range $5.5<\mathrm{}{E}_d<12\mathrm{}$ MeV have been made as follows on the reaction ${\mathrm{C}}^{12}(d, p){\mathrm{C}}^{13*}$: (a) differential cross sections for protons to ${\mathrm{C}}^{13}$ ground state and ${\mathrm{C}}^{13*}$ (3.09 MeV) as functions of angle and energy, (b) proton polarization to ${\mathrm{C}}^{13}$ ground state and ${\mathrm{C}}^{13*}$ (3.09 MeV) as function of energy at 45° (lab system) and as functions of angle (10° to 120° lab) for protons to 3.09-MeV state at $E_d=8.3, 9, \mathrm{and} 10$ MeV, and (c) proton-gamma correlation measurements with the gamma-ray detector on the normal to the reaction plane for reactions to ${\mathrm{C}}^{13*}$ (3.68 MeV) and ${\mathrm{C}}^{13*}$ (3.85 MeV). In (b) and (c) a double-focusing magnetic spectrometer selected the proton group in question; the polarization of the selected protons was measured by observing the "left-right" asymmetry from a carbon scatterer. Backgrounds were made negligible in the polarization work by coincidence methods. All the data show fluctuations with deuteron energy throughout the energy range studied; these fluctuations are attributed to compound-nucleus effects which invalidate a distorted-wave Born approximation (DWBA) stripping interpretation of results at isolated energies although direct interaction is the predominant mechanism. It is shown by taking average values over a wide energy range (∼4 MeV) that a DWBA stripping description of the direct-interaction part of the reaction almost certainly will require the use of spin-dependent potentials.