David Kurt Olsen

Study of some two-nucleon pick-up reactions in the 1p shell with 39.8 MeV protons

Abstract Differential cross sections at a proton energy of 39.8 MeV (lab) have been measured for the following reactions (energies in MeV): 12 C(p,τ) 10 B(g.s., 0.72, 1.74, 2.15, 3.59), 14 C(p, t) 12 C(g.s., 4.43), 14 N(p, τ) 12 C(g.s., 4.43), and 16 O(p,τ) 14 N(g.s., 2.31, 3.95). A zero-range DWBA analysis of the data has been performed using the 1p shell wave functions of Cohen and Kurath. The fits we find are overall somewhat worse in shape than those found in the (p, t) survey of the 1p shell performed by Kahana and Kurath, the principal reason being that of the (p, τ) transitions which proceed with both L = 0 and L = 2 components we find several which occur with a much weaker L = 0 strength than the calculations predict. When ratios of experimental integrated cross sections to DWBA integrated cross sections are compared for all transitions, an rms deviation about the mean of 39% of the mean is found, whereas if only ratios for transitions from a given target nucleus are compared, then the rms deviations are considerably smaller.

The (p, t) and (p, τ) reactions on 17O at 39.8 MeV

Differential cross sections have been measured at forward angles for (p, t) and (p, τ) transitions from 17O to the 12− ground states and lowest-energy 32− states in the 15O and 15N mirror nuclei. The data are compared with DWBA calculations using simple single-particle and single-hole wave functions. When the (p, t) and (p, τ) transitions are considered separately, the calculated and experimental ratios of the 32− integrated cross sections to the 12− integrated cross sections agree to within 30 %; however, the ratios of (p, τ) cross sections to the mirror state (p, t) cross sections are calculated to be about twice as large as actually measured. This experimentally observed reduction of the (p, τ) cross section relative to the (p, t) cross section can possibly be attributed to interference between the S = 0 and S = 1 components of the (p, τ) transitions.