Proton-Proton Scattering at 31.8 Mev, Proportional Counter Method

Differential cross-section measurements for proton-proton scattering have been made with protons of 31. 8-Mev incident energy, scattered from hydrogen at one atmosphere pressure. Seven increments of angles from 15^ to 51^ in the laboratory system of coordinates have been measured simultaneously using proportional counters. In order that measurements could be made with very small currents, axially symmetrical defining slits and counters were made to include large solid angles. A 90^ coincidence method was also used at large angles to give an independent geometry and to detect the possibility of slit and contamination scattering. The ratio of the differential cross section at 30^ to that at 90^, center of mass system, is observed to be compatible with pure S-wave scattering of approximately 50^ phase shift.