Measurement of theZ13contribution to the stopping power using MeV protons and antiprotons: The Barkas effect

Abstract
The stopping power for antiprotons has been measured for the first time. The antiproton stopping power of silicon is found to be 3%19% lower than for equivelocity protons over the energy range 3.01 to 0.538 MeV. The ‘‘Z13 contribution’’ to the stopping power (the Barkas effect) is deduced by comparing the stopping power for protons and antiprotons.