Goto I Miyamoto K Nishioka S Mattei S Lettry J Abe S Hatayama A 2016 To improve the H(-) ion beam optics, it is necessary to understand the energy relaxation process of surface produced H(-) ions in the extraction region of Cs seeded H(-) ion sources. Coulomb collisions of charged particles have been introduced to the 2D3V-PIC (two dimension in real space and three dimension in velocity space particle-in-cell) model for the H(-) extraction by using the binary collision model. Due to Coulomb collision, the lower energy part of the ion energy distribution function of H(-) ions has been greatly increased. The mean kinetic energy of the surface produced H(-) ions has been reduced to 0.65 eV from 1.5 eV. It has been suggested that the beam optics of the extracted H(-) ion beam is strongly affected by the energy relaxation process due to Coulomb collision. application/pdf https://sonar.ch/global/documents/151632 eng info:eu-repo/semantics/altIdentifier/doi/10.1063/1.4934206 info:eu-repo/semantics/altIdentifier/pmid/26932090 info:eu-repo/semantics/openAccess The Review of scientific instruments. - 2016 Effect of Coulomb collision on the negative ion extraction mechanism in negative ion sources. http://purl.org/coar/resource_type/c_6501