Abstract
A simple qualitative quark model has been proposed by Astbury to explain the correlations of structure seen in the total cross sections of certain reactions, when plotted against centre-of-mass momentum. The model predicts structure in the neutron-proton cross section at a laboratory neutron, energy of about 110 MeV and thus has been tested by measurement over a neutron energy range from 25-135 MeV. The measurement was carried out on the Harwell 110" Synchrocyclotron, using the Time-of-Flight Spectrometer, the neutron beam being produced by deflection of the internal proton beam on to an internal aluminium target. The total cross section was derived from the ratios of transmission spectra produced by eicosane wax and graphite absorbers placed in the neutron beam. Owing to the systematic errors being several times the statistical uncertainties (about 1% at 100 MeV), only the relative accuracy of this measurement over the energy range contributes significantly to the previous knowledge of the cross section. No structure however, has been seen in excess of 2. 9 mb.MeV/c area in any part of the energy range measured in this experiment.