LOW-Q (D N) STRIPPING REACTIONS ON 10B 12C AND 13C

Differential cross sections are presented for the low-Q transitions (i) 10B(d, n5)11*C (6.49 MeV), (ii) 12C(d, n0)13N and (iii) 13C(d, n3)14*N (4.91 MeV). Neutrons were detected by time-of-flight techniques, and the absolute cross sections for reactions (i) and (iii) were estimated from measurements of the absolute efficiency of the neutron detector. Because the neutron energies are very low in reaction (ii), the cross section was calculated from absolute measurements of the position activity of the residual 13N nuclei. Theoretical fits were attempted using (i) Butler plane wave Born approximation, (ii) Coulomb stripping theory of Morinigo and (ii) distorted wave Born approximation (DWBA). Acceptable fits to all three reactions could only be achieved with the DWBA, thus indicating the importance of the nuclear distortion of the deuteron and neutron waves. The DWBA fits were rather critical with respect to the optical model and radial cut-off parameters with slight variations in these impairing the quality of the fits. Reactions (i) and (iii) exhibited the characteristic stripping patterns, while reaction (ii) exhibited a backward peaking interfering with the forward stripping peak. The optical-model parameters for all three reactions are summarized. Best fits to reactions (i) and (ii) were obtained with a cut-off radius which varied slowly with energy, but reaction (iii) favoured the non-cut-off theory. © 1969.