Progress Report [2. Research Coordination Meeting on Heavy Charged-Particle Interaction Data for Radiotherapy]

Full text: Proposed work: a) Calculation of proton-induced integrated, differential and double differential cross section and comparison with experimental data for a wide range of biological and structural elements, using exclusive a Double Differential Hybrid Monte Carlo Simulation (DDHMS) pre-equilibrium model (code to be developed and integrated into the EMPIRE system) coupled to Hauser-Feshbach or fragmentation equilibrium decay models (code for the latter must also be developed and integrated into the EMPIRE system). b) Compare evaluated data files for proton-induced reactions (LA-150, JENDL, JEFF3.1 or ENDF/B-VII) with experimental data. Progress: a) An exclusive DDHMS module (XDDHMS) was developed but is still only partially integrated into the EMPIRE system. Residual populations are passed to the system so that equilibrium Hauser-Feshbach decay can be calculated. Differential and double-differential data accumulated in the calculation are converted from histogram to point data, for compatibility with the system, but are not yet passed correctly to the main program, so that complete spectra and double differential cross sections cannot be calculated. b) The double-differential cross sections from XDDHMS calculations were compared with experimental data for proton-induced reactions on C, O, Al, Fe and Pb in the energy range from 14 MeV to 200 MeV. In general, the proton double-differential data are well described by the calculations at higher energies, although the cross section at backward angles tends to be underestimated. Discrepancies between the calculations and the proton double differential data increase as the energy decreases. The agreement of the calculations with neutron double differential data is at best only fair at high energies and also decreases as the energy is decreased. To try to improve these results, the algorithm for particle-hole energy selection will be modified to use a Fermi distribution rather than an equally spaced one and parameters will be tweaked. c) ENDF-B/VII evaluated data files for proton-induced reactions were compared with experimental nonelastic reaction data for C, N, O, Ca, Fe and Pb. The evaluations extend up to 150 MeV. Their agreement with the experimental data was found to be quite good. d) The rest of the proposed work was not completed, although work on the fragmentation module for the EMPIRE system has begun.