LYMAN-ALPHA 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- 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 (=0 for normal incidence) and surface temperature (300-600°K). Yields exhibited incident angle dependences of sec 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- 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. © 1979 The American Physical Society.