  Photoelectron emission measurements have been performed using a
filament-driven multi-cusp arc discharge volume production H^- ion source
(LIISA). It has been found that photoelectron currents obtained with Al, Cu,
Mo, Ta and stainless steel (SAE 304) are on the same order of magnitude. The
photoelectron currents depend linearly on the discharge power. It is shown
experimentally that photoelectron emission is significant only in the short
wavelength range of hydrogen spectrum due to the energy dependence of the
quantum efficiency. It is estimated from the measured data that the maximum
photoelectron flux from plasma chamber walls is on the order of 1 A per kW of
discharge power.
