The energy distribution of fast atoms produced by modifying a McIlraith-type fast atom beam (FAB) source is measured using a retarding-field energy analyzer coupled with an ionization chamber. The energy distribution mainly depends on the gas pressure of the FAB source. When the gas pressure is low, the main energy distribution peak coincides with the discharge voltage, so the acceleration energy of the ions is retained when they become fast atoms. When the gas pressure is high, the peak energy appears at about 25% of the discharge voltage and has a broader spectrum. The energy distribution is almost completely independent of the discharge voltage, discharge current, and the geometry of the source anode. The fast atoms are mainly produced by resonant charge-transfer collisions inside the source. These collisions are dominant over electron-ion recombinations for FAB formation.
ASJC Scopus subject areas
- Physics and Astronomy(all)