C12(p,pn)C11cross section at 800 MeV

The ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(p,pn){}_{}{}^{11}{}_{}{}^{}\mathrm{C}$ reaction cross section has been measured at 800 MeV by the method of activation analysis. The value of 32.0 ± 1.0 mb is about 8% greater than the normally used interpolated value of Cumming.