Antiproton Interactions in Hydrogen and Carbon below 200 Mev

About 500 antiprotons in a partially purified antiproton beam have been observed to enter the 30-in. propane bubble chamber. An arrangement of counters identified the antiproton events, thus reducing scanning to a minimum and also providing a sample of antiprotons free of scanning bias. The antiprotons entered the propane at a kinetic energy of 220 Mev and were brought to rest. Scattering and annihilation interactions in both hydrogen and carbon have been observed as a function of antiproton energy. Differential scattering cross sections have been obtained, and the following total cross sections have been measured for antiproton kinetic energies, $T$, in the ranges 75 to 137.5 Mev and 137.5 to 200 Mev: The above results show satisfactory agreement with the Ball-Chew theory where comparison can be made.