Robert L. White

A useful spectroscopic tool: The (7Li, 6He) reaction☆

Angular distribution measurements for the reactions 24Mg(7Li, 6He)25 Al and 52Cr(7Li, 6He)53 Mn atE(7Li) = 34 MeV show that for angles less than 15°, the shapes of the measured angular distributions allow d52 or d32, and f72 or f52 final-state configurations to be distinguished when compared with finite-range DWBA calculations.

Anomalous results for the 9Be(α, t)10B and 13C(α, t)14N reactions at Eα = 27 meV

Abstract Angular distributions for the reactions 9Be(α, t)10B and 13C(α, t)14N have been measured at Eα = 27 MeV in the angular range 15°–110° c.m. for transitions to the first four states in 10B and the first five states in 14N. Excitation functions for 9Be(α, t)10B measured at the lab angles 25° and 45° in the energy range 26–27.5 MeV showed little structure indicating a small compound nucleus contribution. For both reactions the transition to the 0+T = 1 state is suppressed by at least a factor of five compared to the transition to the T = 0 states. DWBA and CCBA calculations gave a poor description of the data and did not predict the suppression of the T = 1 transitions in the (α, t) reactions. A reanalysis of more recent (d, n) and (τ, d) data in terms of the Cotanch-Robson isospin dependent DWBA model, which explains the spectroscopic factor ratio for T = 1 T = 0 transitions in the two reactions, is also presented.

The 9Be(α, d)11B reaction at Eα = 27 MeV

Abstract Angular distributions have been measured at Eα = 27 MeV for the 9Be(α, d) reaction to the first seven states in 11B for the angular range 7.5°–120° c.m. Excitation curves have been measured in the energy range from 26.5 to 27.5 MeV in 100 keV steps at the lab angles 40°, 60° and 90°. No evidence for non-direct processes was observed. DWBA calculations with Cohen-Kurath spectroscopic amplitudes were moderately successful in describing the transitions to the 0, 2.12 and 5.02 MeV states. The transition to the 4.44 MeV state did not exhibit a stripping pattern and is characteristic of multi-step transitions.