Production of a 10 eV–1000 eV neutral particle beam using surface neutralization

For the calibration of low-energy neutral particle mass spectrometers a neutralization stage for a charged-particle beam was built. The incident positive ion beam is neutralized upon reflection at grazing incidence off a highly polished tungsten single crystal surface. With protons as primary species the device produced a neutral hydrogen beam in the energy range of 10 eV–1000 eV depending on incident ion-beam energy with a centre energy of 85% to 89% and an energy width of 11% to 15% FWHM of the incident ion energy. The angular spread of the neutral beam was limited by apertures to 4.6° × 18° FWHM. The overall transmission of the device was found to be between 0.005 and 0.013.