Lyman- α emission from proton bombardment of Si, Cu, Ge, Mo, Ta, and Pt surfaces

A 0.3-m vacuum monochromator has been used to observe Lyman-α emission from polycrystalline Mo, Ta, Pt, and Cu and from single-crystal n-type Ge and Si surfaces under 6.5-12.5-keV proton bombardment. The viewing direction was fixed at 60^∘{} relative to the proton-beam axis. The absolute photon yields were determined as a function of beam-surface incidence angle (θ=0 for normal incidence) and surface temperature (300-600 ^∘{}K). Yields exhibited incident angle dependences of secθ or stronger, and temperature coefficients were positive for Mo and Ta, negative for Cu, and nearly zero for Ge. Doppler-shift profiles of the Lyman-α emission were used to determine the backscattered, excited-hydrogen-atom energies. Absolute photon yields between about 10^-4 and 10^-2 photons/proton were obtained. The yields were insensitive to background H₂ gas pressure between 5×{}10^-9 and 10^-7 Torr.