Proton-Proton Scattering at 240 Mev

Differential proton-proton scattering cross sections have been measured at six angles in the range from 27 to 90 degrees center of mass. The internal undeflected cyclotron beam was used with a hydrocarbon target. Proton-proton scattering was differentiated by detecting the emitted proton pair with its definite angle between particles in coincidence with two scintillation counters. Scintillator dimensions determined the solid angle accepted. The incident beam was monitored by measurement of the beta-activity induced by the reaction C¹²(p,pn)C¹¹ in the target. General cyclotron background was negligible.The cross sections measured show isotropy in the center-of-mass system within estimated errors. The average value of the cross section was 4.97±{}0.43 millibarns/steradian based on a 49±{}3 millibarn carbon cross section. This is in poor agreement with previous measurements of 3.6±{}0.3 mb/steradian.