Cross sections and analysing power energy-sharing distributions of valence (p,2p)-knockout from 208Pb with a projectile of 200MeV

[摘要] ENGLISH ABSTRACT:The aim of this work was to study the 208Pb(p,2p)207Tl quasi-free knockout process. Theexperimental data were measured at the National Accelerator Centre using incident polarisedprotons of 200 MeV. The two scattered particles, from the knockout reaction, were detectedin coincidence and their energies were determined using a magnetic spectrometer and a solidstate detector telescope.Cross section and analysing power energy distributions were extracted from the experimentalmeasurements and these were compared with theoretical values for the Distorted WaveImpulse Approximation. The theoretical cross-section calculations predict the experimentalcross-section distribution well for all combinations of distorting potentials and bound statesthat were investigated, both with regard to shape, as well as absolute magnitude. Howeverthe theoretical analysing power distributions did not agree with the experimental quantities.Therefore it is not clear whether the analysing power is a useful tool to extract information onthe specifics of the quasi-free reaction mechanism. The spectroscopic factors were found tobe consistent with the results obtained in previous studies, thereby inspiring confidence thatthe problem with the analysing power distribution is not ascribable to a possible deficiency inthe experimental techniques exploited in this work.

[发布机构] Stellenbosch University