Energy and angular distributions of electrons ejected from water vapor by 0.3–1.5 MeV protons

Absolute cross sections, differential in electron energy and ejection angle, have been measured for ejection of electrons from water vapor by protons with energies from 0.3 to 1.5 MeV. These cross sections are compared with similar measurements for ionization of molecular hydrogen and oxygen and previously published results for hydrocarbon. The criteria for additivity and scalability of electron ejection cross sections are discussed.