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

Abstract

A 0.3-m vacuum monochromator has been used to observe Lyman-$\ensuremath{\alpha}$ 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\ifmmode^\circ\else\textdegree\fi{} relative to the proton-beam axis. The absolute photon yields were determined as a function of beam-surface incidence angle ($\ensuremath{\theta}=0$ for normal incidence) and surface temperature (300-600 \ifmmode^\circ\else\textdegree\fi{}K). Yields exhibited incident angle dependences of $sec\ensuremath{\theta}$ 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-$\ensuremath{\alpha}$ emission were used to determine the backscattered, excited-hydrogen-atom energies. Absolute photon yields between about ${10}^{\ensuremath{-}4}$ and ${10}^{\ensuremath{-}2}$ photons/proton were obtained. The yields were insensitive to background ${\mathrm{H}}_{2}$ gas pressure between 5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}9}$ and ${10}^{\ensuremath{-}7}$ Torr.