Tensor polarization of deuterons from the 9Be(p, d) 8Be reaction for Ep = 1.6–3.8 MeV

Abstract

The tensor polarization of the deuterons from the 9Be(p, d) 8Be reaction was measured for proton energies in the range 1.6–3.8 MeV and for lab emission angles between 10° and 90°. The tensor polarization was measured by observing the deviation from isotropy of the angular distribution of the 3He(d, p) 4He reaction, when the deuterons from the 9Be(p, d) 8Be reaction were incident on a 3He gas cell with energies below 600 keV. The largest magnitude of polarization observed occured at E p = 2.0 MeV, θ lab = 10° , where t 20 was found to be 0.53 ± 0.08. For proton bombarding energies below 2.6 MeV, a pronounced energy dependence of the polarization is present, while in the energy range 2.7–3.8 MeV less variation was observed. Neither a DWBA calculation using spin-orbit potentials nor a plane-wave calculation including deuteron D-state effects has been successful in reproducing the magnitude and angular variation of the tensor polarization data, although the differential cross-section data above E p = 2.5 MeV strongly suggest that the (p, d) “pick-up” reaction is the predominant reaction mechanism at these bombarding energies.