分类: 物理学 >> 核物理学 分类: 物理学 >> 交叉学科物理及相关领域的科学与技术 提交时间: 2023-06-20
摘要: The Shanghai laser electron gamma source (SLEGS) is a powerful tool for exploring photonuclear physics, such as giant dipole resonance (GDR) and pygmy dipole resonance, which are the main mechanisms of collective nuclear motion. The goal of the SLEGS neutron time-of-fight (TOF) spectrometer is to measure GDR and specifc nuclear structures in the energy region above the neutron threshold. The SLEGS TOF spectrometer was designed to hold 20 sets of EJ301 and LaBr3 detectors. Geant4 was used to simulate the efciency of each detector and the entire spectrometer, which provides a reference for the selection of detectors and layout of the SLEGS TOF spectrometer. Under the events of 208Pb, implementations of coincidence and time-of-fight technology for complex experiments are available; thus, y and neutron decay events can be separated. The performance of SLEGS TOF spectrometer was systematically evaluated using ofine experiments, in which the time resolution reached approximately 0.9ns.
分类: 核科学技术 >> 辐射物理与技术 提交时间: 2023-06-01
摘要: In recent years, graphics processing units (GPUs) have been applied to accelerate Monte Carlo (MC) simulations for proton dose calculation in radiotherapy. Nonetheless, current GPU platforms, such as CUDA and OpenCL, suffer from cross-platform limitation or relatively high programming barrier. However, the Taichi toolkit, which was developed to overcome these difficulties, has been successfully applied to high-performance numerical computations. Based on the class II condensed history simulation scheme with various proton-nucleus interactions, we developed a proton MC transport GPU-accelerated engine using the Taichi toolkit. Dose distributions in homogeneous and heterogeneous materials were calculated for 110, 160, and 200 MeV protons and were compared with those obtained by full MC simulations using Topas. The gamma passing rates were greater than 0.99 and 0.95 with criteria of 2 mm, 2% and 1 mm, 1%, respectively, in all the tested conditions. Moreover, the calculation speed was at least 5800 times faster than that of Topas, and the number of lines of code was approximately 10 times lesser than those of CUDA or OpenCL. Our study provides a highly accurate, efficient, and easy-to-use proton dose calculation engine for algorithm developers, students, and medical physicists.