RT2QMD: GPU-Accelerated nucleus-nucleus fragmentation event generator
Description
We developed a GPU-accelerated nucleus-nucleus fragmentation event generator. The Quantum Molecular Dynamics (QMD) model was implemented on GPU architecture. A corresponding evaporation model was also integrated to handle de-excitation. The developed models, RT2QMD, can handle nuclear collisions where the projectiles including oxygen isotopes and lighter nuclei, covering most of the situations in carbon-ion radiotherapy. The intended energy range of this package is 100 MeV/u to 500 MeV/u. This package was compared against the corresponding Geant4 models and experimental data. The RT2QMD showed good agreement with Geant4 and experimental data for neutron double-differential cross-section in the 290 MeV/u 12C(12C,xn), 12C(16O,xn) reactions, and the 230 MeV/u Cu(4He,xn) reaction. The fragment production cross-section from 12C - 12C reactions showed relatively large differences compared to Geant4 and experimental data, due to the simplified evaporation model. The RT2QMD ran on an NVIDIA RTX 4090 GPU, while the Geant4 models ran on an Intel Xeon Gold 6342 node using all 48 available threads. The computing speeds of RT2QMD were about 30 times faster than those of Geant4 for all reactions. This package is part of the GPU-based Monte Carlo code, RT2, to handle dose calculation in heavy-ion therapy.