Theoretical study of W-values for particle impact on water

Veronica Tessaro (1, 2) , Floriane Poignant (2) , Benoit Gervais (3) , Michaël Beuve (2) , Mariel E. Galassi (1)

1 IFIR - Instituto de Física de Rosario [Santa Fe]
2 PRISME - PRISME
3 CIMAP - UMR 6252 - Centre de recherche sur les Ions, les MAtériaux et la Photonique

The W-values and the differential values w, were calculated by electron, proton and antiproton impact on liquid and vapor water. Two different theoretical approximations were used: the Fowler Equation (based on the Continuous Slowing Down Approximation), and the Monte Carlo code MDM, which does an event-by-event tracking of all generated particles in the media. The dependence on the type and charge of the projectiles and the relevance on the appropriate inelastic cross sections employed in the calculations were studied. For electron impact, results obtained with both models are in good agreement with experimental data and with other theoretical calculations. However, the MDM results are more representative of the stochastic nature of radiation-media interactions. The w-values for swift proton and antiproton impact on vapor water, calculated using the Fowler Equation, are in very good agreement with the results obtained by electron impact in the same velocity regime.

Mots clés: Ion-electron pairs; W-values; Stopping; Ionization

Domaines: Modélisation et simulation; Physique Médicale [physics.med-ph]

Veronica Tessaro, Floriane Poignant, Benoit Gervais, Michaël Beuve, Mariel E. Galassi. Theoretical study of W-values for particle impact on water. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2019, 460, pp.259-265. ⟨10.1016/j.nimb.2018.11.031⟩. ⟨hal-01980804⟩