Investigation of the (p,t) reaction as a potential surrogate for (n,gamma)

A theoretical model has been developed to predict the excitation energy, spin and parity distributions of the residual nuclei following a (p,t) two-neutron transfer reaction. These distributions may be compared with those expected for the same residual nucleus produced via an (n, ) reaction and therefore provide information on whether (p,t) can be used as a suitable surrogate in cases where an (n, ) reaction cannot be observed directly. The model developed predicts the possible spin, parity and energy values of the discrete excited states populated in the residual nucleus and calculates the absolute strength of each transition, including both the dynamical and structural components of the cross section. The model has been designed to be purely predictive and to require little or no detailed prior information on the target nucleus in question. The model developed has been applied to the case of 28.53 MeV protons incident on an isotopically enriched 92Zr target, a case for which experimental data have recently been taken by another research group using the STARLiTeR detector at Texas A&M University. Data exist for the triton energy spectrum, triton angular distributions in the range 25 - 60, and coincident -ray decay spectra. A detailed comparison between the model and data shows a reasonable match to the average trends, but a breakdown when individual discrete states are scrutinised in detail. In particular, the model fails to predict the population of a number of physical states observed in 90Zr, suggesting a more sophisticated approach to the structural and/or dynamical components of the model is required. Possible alternative methods and extensions to the physics of the model, in order to address the discrepencies with the measured data and to allow the model's application to more diverse physical systems, are also discussed