THE FLUKA MONTE CARLO CODE: LATEST VALIDATION AND BENCHMARKS

FLUKA simulates transport and interactions of a variety of particles and heavy ions. Applications range from micro and clinical dosimetry to LHC (Large Hadron Collider) and cosmic domains. In addition to prompt emissions, delayed radiation may be simulated for user-specified cooling times. Ongoing code development progresses alongside validation and benchmarks. This work reports 1) comparison of electromagnetic showers against PENELOPE, a Monte Carlo code specialized in electromagnetic simulations; and 2) benchmarks against measured data, particularly for beam-target combinations where measured data are sparse, e.g. ~100 MeV per nucleon carbon ion beams impinging tissue-equivalent phantoms, emitting photons and heavy fragments. Such emissions, if detected experimentally, provide invaluable data for benchmarking FLUKA implementation of gamma de-excitation, Boltzmann Master Equations and Relativistic Quantum Molecular Dynamics Model. Whereas comparison with measured data fulfils ultimate benchmarking, comparison with an independently-developed simulation code provides fully-controlled conditions, free of confounding factors inevitable in physical measurements. Excellent agreement has been found, among others: 1) pulse-height spectrum from MeV-range photons impinging a LYSO scintillator crystal agreed with PENELOPE tightly within statistical uncertainty without any observable systematics; 2) position-sensitive pulse height spectra at 90o resulting from thick-target irradiation by 80 to 310 MeV per nucleon carbon and proton beams agreed with measured data well within experimental uncertainty. Successful and seamless simulation of radiometric quantities under such intermediate-energy and low-Z configurations addresses exactly the concerns where the radiation physics community needs confidence in, e.g. hadrontherapy and beyond.