Measurement of nuclear activation cross sections of protons on natural carbon for proton beam energies between 100 and 220 MeV

In this work, we present measurements of nuclear activation cross sections from carbon. Carbon can be used for proton fluence calculation in proton therapy by measurements of the activity after irradiation. The cross sections are measured on a high-precision level with systematic uncertainties of approx. 2.8% for proton beam energies between 100 and 220 MeV. The targets are activated at the West German Proton Therapy Centre Essen. The determination of the activity is based on gamma-ray spectrometry measurements at the Dortmund Low Background Facility. For the C-nat(p,x)C-11-reaction the results of this experimental study are comparable with several measurements reported in the literature. For the C-nat(p,x)Be-7-reaction, the results calculated by several groups are reproduced by these measurements up to 180 MeV. Above 180 MeV, the observed energy dependence is weaker than the one measured by other groups. The reproducibility of the experimental setup is demonstrated with a measurement of the cross sections from aluminum.