Measurements of d, p[gamma] directional correlations in 20F

Abstract

The reaction 19F(d, p[gamma])20F was used to measure the directional correlations of the proton groups in coincidence with subsequent gamma radiations produced in de-excitation of the 2.05, 1.31, 1.06, 0.99 and 0.65 MeV levels of 20F. The effective deutron energy was 0.448 Mev. For the 2.05 MeV level, the 1-2 correlation between the protons and the 1.40 MeV gamma transition to the first excited state was measured simultaneously with the 1-3 correlation between the same proton energy group and the 0.65 MeV gamma transition, with the intermediate 1.40 MeV gamma radiation unobserved. These correlations were measured in two configurations: one with the protons being detected at an average angle of 170[deg] with the beam passing through a centre hole in an annular-shaped detector, and the other with a disc-shaped detector at 135[deg] and the gamma detector moving in the plane of the reaction. A plane-wave analysis of these data gave essentially identical correlation coefficients for these two configurations.Directional correlations were also measured in the 170[deg] configuration between the proton energy groups and the subsequent ground-state gamma transitions from the 1.31, 1.06, 0.99 and 0.65 and 0.65 MeV levels. A plane-wave analysis of these data is compared with a distorted-wave analysis of related data from a previous experiment. A thorough computational comparison between all of these data and the predicted correlations, based on a plane-wave analysis using postulated spin values which are consistent with the proton angular distribution data, did not yield a unique spin value for any of these levels. It was possible in some cases, however, to put rather stringent conditions on the ratios of the angular-momentum matrix elements associated with the incoming and outgoing radiations which are compatible with the postulated spins.