Therapeutic purpose 9C beams produced in the secondary beam line at HIMAC

Abstract

Due to the favorable characteristics of heavy-ion beams such as dose localization as well as high relative biological effectiveness, heavy-ion cancer therapy is attracting growing interests all over the world. The application of β-delayed particle decay beams like 9C ions in cancer therapy is expected to further improve the treatment efficacy of the modality of heavy-ions. For the first time 9C beams were produced in the secondary beam line (SBL) of the HIMAC facility with a primary 12C beam of 430 MeV/n. The production conditions providing a 9C beam with higher production rate and purity were optimized using different thick production targets and degraders. The results show setting the momentum acceptance to the full value of 5% the production rate is 9.07 × 10 −6 and the purity is 82.88% for the produced 9C beam under the optimal condition. Because of the large momentum spread for a secondary beam, the momentum distribution of the produced 9C beam at the optimal condition was measured. The momentum among the beam had a nearly Gaussian profile with a standard deviation of 26.1 MeV/c/n and the largest component of the momenta appeared around 838.9 MeV/c/n. In order to form a relatively large uniform irradiation field being appropriate to further biological experiments for the produced 9C beam, the scanning magnets in the irradiation system of the SBL, operating in a wobbling mode, was used. A uniform irradiation field of 20 mm in diameter could be achieved with homogeneity of 93.8%. The work presented in this paper provides a substantial basis for the further studies with 9C beams for the therapeutic purpose.