Measurement of cross section of proton-induced reactions on oxygen with silicon dioxide target

Oxygen is one of the most common elements in the human body. Proton beams used in therapy induce nuclear reactions that cause a loss of fluence along the beam path. These reactions often lead to production of \(\beta ^+\) emitters with relatively short half-lives (less than 20 min). Cross sections for reactions on oxygen are not sufficiently known, particularly at proton energies above few tens of MeV. This contribution presents the results of an experiment, where silicon dioxide targets were used to study nuclear reactions induced by protons with energy below 60 MeV on oxygen. The proton beam was delivered by the AIC-144 cyclotron of the Institute of Nuclear Physics in Kraków. Cross sections of reactions leading to production of \( ^{11}\)C, \( ^{13}\)N and \( ^{15}\)O were obtained. They agree well with the measurements using Cherenkov radiation in bulk SiO\(_2\). The recent measurements performed with a PET scanner provided similar results, except in the case of \( ^{16}\)O(p,x)\( ^{11}\)C reaction studied in the energy of up to 200 MeV, where our results are 30% lower.