A semiempirical model of single differential cross sections (SDCS) for ionization of water vapor by fast electrons and bare ions is presented. At low secondary-electron energy, the model is based on an asymptotic expansion of the first Born approximation with coefficients, that are independent of projectile properties, evaluated from experimental photoabsorption and protonimpact ionization data...

Simulations studies have been carried out to examine the impact of the energy of the proton driver on muon production. The muon flux is calculated as a function of proton energy over a wide range, which covers the energies at the existing muon and neutron facilities worldwide. The muon and higher energy pion yields are normalised per beam current and accelerator power. The case of a higher ener...

PURPOSE To develop a nano-dosimetric Monte Carlo simulation package, TOPAS-nBio, based on the TOPAS (TOol for PArticle Simulations) framework that is being developed in a collaboration between the Massachusetts General Hospital (MGH), the SLAC National Accelerator Laboratory and the University of California, San Francisco. The goal is to incorporate biological processes on a sub-cell level that...

A series of simulations were conducted with Geant4 in order to verify the electron backscattering experiments performed by Tabata low Z elements Be, C and Al. In general, a quite good agreement was obtained carefully choosing physics lists employed. These results invalidate claim made before Kirihara et al about presence experimental errors Tabata’s work.

In this paper we present the results of GEANT4 simulations of the production of surface muons as a function of energy of the incident protons on a graphite target. A validation of the GEANT4 hadronic physics models has been performed by comparing the results with experimental data from the Lawrence Radiation Laboratory, United States. Considering the ISIS muon target as a reference, simulations...

The role of inelastic collisions in Hall thruster operation is studied through simulation of the electron energy distribution function (EEDF) inside the thruster channel. The electron Boltzmann equation is solved using the Lorentz approximation (two-term expansion) and the "local-field" approximation. The resultant zero-dimensional Boltzmann equation takes into account inelastic losses due to i...

The modelling with the Geant4 toolkit of moderated 3He-filled proportional neutron counters is studied. The energy deposition spectra by the neutron capture products in the gas counter is compared with experimental results. On the other hand, efficiency calculation for polyethylene moderated proportional counters are compared with experimental and MCNPX results.Finally, the application of the G...

The authors report results from computational studies of the interaction of low-energy electrons with the purine bases of DNA, adenine and guanine, as well as with the associated nucleosides, deoxyadenosine and deoxyguanosine, and the nucleotide deoxyadenosine monophosphate. Their calculations focus on the characterization of the pi* shape resonances associated with the bases and also provide g...

Anionic states of nucleic acid bases are involved in DNA damage by low-energy electrons and in charge transfer through DNA. Previous gas phase studies of free, unsolvated nucleic acid base parent anions probed only dipole-bound states, which are not present in condensed phase environments, but did not observe valence anionic states, which for purine bases are thought to be adiabatically unbound...