The C(α, X)11C cross sections at 1.59 and 4.19 GeV

The absolute cross sections for the production of 11C by 1.59 GeV and 4.19 GeV α-particles incident on natural carbon have been measured to be 46.4 ± 1.3 mb and 42.5 ± 1.1 mb respectively. These results, together with data reported at other energies, indicate that the C(α, X)11C cross section becomes approximately constant at a value of about 43 mb for energies above 3 GeV (750 MeV/n). A similar energy dependence is exhibited by the C(p, X)11C reaction whose cross section has been measured previously over an extensive energy range. The C(α, X)11C cross sections are found to be in good agreement with predictions of a semi-empirical model developed to describe nuclear fragmentation.