Ionization and electron capture for H+ collisions at low keV energy with a water-vapor target

We have investigated the total relative ionization and dissociative electron capture cross section for proton collisions with water-vapor molecules within the energy range of 2.5–10 keV. Time of flight mass spectroscopy was employed in the measurements of the atomic and molecular singly charged particles H+, H2+, O+, OH+ and H2O+ as well as the doubly charged particles O++, H2O++, OH++, and the contribution of the different channels was evaluated. Ionization was found to be the dominant reaction channel as expected. The contribution of the singly charged particles was found to be one order of magnitude higher than that of the doubly charged particles.