A COMPARISON OF DESORPTION YIELDS FROM C-60(+) TO ATOMIC AND POLYATOMIC PROJECTILES AT KEV ENERGIES

The desorption yields of negative ions from the impacts of keV energy C-60(+), (CsICs+ n=0,1) and Ga+ primary projectiles are compared. The experiments were performed in the event-by-event bombardment and detec tion mode using primary ion energies that ranged from 12 to 32 keV. Sa mples studied were vapor-deposited targets of CsI and phenylalanine. C ompared at the the same energy, C-60(+) produces 5 to 80 times higher secondary ion yields than Cs+ or Ga+, primary ions commonly used in se condary ion mass spectrometry.