Detection Of Hydrogen Adsorbed On Tungsten Surfaces Using The H-1(N-15, Alpha-Gamma)C-12 Reaction

An ultratugh vacuum (UHV) system for the 1 H( 15 N, αγ) 12 C reaction analysis of hydrogen adsorbed on well-defined surfaces was constructed. The detection limit of hydrogen coverage on the W(001) surface was 4 × 10 13 H atoms/cm 2 ( 1 50 of the full monolayer coverage). The ion-stimulated desorption process for hydrogen atoms due to the 15 N ion beam was studied by measuring the decay of hydrogen coverage on W(001) at low background gas pressures, and the desorption cross section was obtained as 2.4 × 10 −16 cm 2 . Hydrogen coverage on the W(110) surface compared with that on W(001) was estimated from the intensity profiles given by measurement of the resonance energy width.