Proton-Proton Scattering at 5 Mev

Abstract

A scattering chamber has been constructed which employs a number of radial slit units arranged at various angles with respect to the collimated beam of protons. A photographic plate is placed behind each slit unit and the tracks of protons which are scattered into the plate can be counted. To obtain cross sections from this apparatus the number of tracks per unit area must be determined. Protons were scattered from hydrogen gas at approximately 1.5-cm Hg pressure. Advantages of the design were relatively simple geometry, data obtained simultaneously at all angles, almost complete freedom from impurity-scattering, and short cyclotron running times. The differential cross sections were measured for 5.07-Mev protons from 14° to 150° in the center-of-mass system. The results indicate an $S$-wave phase shift of 54.5±0.6° and a repulsive $P$-wave phase shift of 0.05±0.09°. They are therefore quite consistent with pure $S$-wave scattering.