The elastic scattering of protons from He 3 from 4.5 to 11.5 MeV

Abstract

He 3(p, p)He 3 cross sections have been measured for incident proton energies from 4.5 to to 11.5 MeV using a tandem Van de Graaff accelerator. Excitation functions at centre-of-mass angles of 90°, 125°18′ and 161°12′ were measured from 4.5 to 10.4 MeV in steps of 200 keV, and no sharp structure was observed. Angular distributions were measured from 27°38′ to 166°35′ in the centre-of-mass system at bombarding energies of 4.55, 5.51, 6.52, 7.51, 8.51, 9.51, 10.38 and 11.48 MeV. A phase shift analysis has been made of these data using one phase shift for each of the values of l through l = 2. The P-wave phase shift was found to be increasing with energy (in qualitative agreement with earlier analyses). Cross sections calculated from the phase shifts show large deviations from the experimental values in the region around 100° in the centre-of-mass system. This indicates that some spin -dependent splitting of the phase shifts is required to fit the data.