Track electrostatic model for describing secondary ion emission of insulators

Abstract

A model based on the nuclear track potential is described and used to predict trajectories and the energy distribution of secondary ions emitted by insulating targets. In this model, the electric field generated by each track pushes away the secondary ions formed on the target surface. The effects on the potential due to target thickness, track charge density, projectile incidence angle and secondary ion mass are analyzed. Predictions are compared with experimental data existing in the literature. It is found that the proposed model describes partially the behavior observed in the angular distribution of the emitted ions and new processes are proposed to be included in the model.

Space weathering on inner planetary surface analogues induced by swift multicharged heavy ion bombardment

“…Indeed, when heavy multicharged ions (e.g. cosmic rays, FFs) interact with a solid, emission of secondary electrons occur together with neutral and ionic species (Iza et al 2005, Martinez et al 2006); a plasma is temporary formed, favoring electron attachment (Macfarlane & Torgerson 1976, Oliveira et al 2021. In other words, electron attachment cross sections are enhanced on the surface in part because of multiple scattering of electrons and adjacent species.…”

“…The heavy ion projectiles are fission fragments (FF) emitted by a 252 Cf source. Experiments with FF (e.g., 105 Rh and 140 Ba) with atomic numbers close to that of heavy constituents of CR are indeed a good simulation of effects induced by the heavy ion fraction (a few percent) of cosmic rays (Farenzena et al 2005, Martinez et al 2014. Under these conditions, the FF-silicate interaction yields an electronic (inelastic) stopping power of about 5 keV/nm, i.e.…”

Dessorção Iônica Induzida Por Íons Energéticos Pesados Em Gelos Astrofísicos: H2o, C2h2, C2h6 E N2o

“…Se o elétron emitido tiver baixa energia cinética (de até alguns eV), é muito provável que ele seja capturado por espécies moleculares próximas, formando ânions; se possuir dezenas de eV, eles provocam novas ionizações, formando cátions nas moléculas vizinhas. Desde que esses ânions ou cátions sejam produzidos perto da superfície alvo, eles podem escapar do sólido como íons secundários (ver, Iza et al (2005) e referências nele indicadas).…”

“…Devido à atração entre as cargas opostas, tem-se que uma fração dos íons secundários negativos é retida ou desacelerada pelo traço positivo formado com a emissão dos elétrons secundários. Pela mesma razão, a repulsão entre o traço positivo e os íons secundários positivos gera uma maior emissão deles e com maior energia (IZA et al, 2005).…”