Comparison of validations of GEANT4 and FLUKA codes on photo-nuclear predictions in the high-energy range.

Quintieri L., Pia M.G., Augelli M., Saracco P., Capogni M., Guarneri G.
  Venerdì 30/09   15:00 - 18:00   Edificio Psicologia 2 - Aula 3G   VI - Fisica applicata, Acceleratori e Beni Culturali
The simulation of photo-nuclear interactions provides a relevant and valuable support in many research fields of applied physics: design and optimisation of photo-hadronic sources ($i.e$ production of neutrons, pions, special radionuclides for pharmaceutical applications, etc.) as well as design and optimisation of shields of high-energy particle accelerators (mainly for issues related to photo-neutrons). An assessment of the reliability of such simulations based on widely used Monte Carlo codes (with emphasis on GEANT4, FLUKA and MCNPX) is presented: it consists of quantitative validation tests, based on statistical data analysis methods, which compare simulated and measured observables in relevant scenarios, whenever experimental data are available. The goal of our work is to investigate quantitatively the reliability of extensively used Monte Carlo codes to simulate experimentally relevant observables involving photon-nuclear interaction modelling, over a wide energy range (up to several hundreds GeV). The evaluation of the reliability of the simulations is carried out by quantifying the validity of simulated observables through statistical comparisons with experimental data, where they exist, and by assessing objectively knowledge gaps due to lack of measurements suitable for the purpose of validating the simulation outcome. When experimental measurements of the simulated observables are not available in the literature, an effort is made to identify the underlying primitive physics parameters (total and differential cross sections, nuclear and atomic parameters etc.) used in the Monte Carlo transport models, and to assess the status of their validation. We report, in detail, the comparison of the predictions, in terms of evaluated hadron yields and energy spectra, in a wide energy range (up to GeV scale) for natural tungsten (one of the most used material for shielding). The benchmarking of the code predictions with the experimental data of the photo-neutrons produced on natural tungsten with a 0.51 GeV electron beam, at the DA$\Phi$NE Beam Test Facility of LNF, is also presented and discussed.