  We study two techniques to create electrons in a liquid helium environment.
One is thermionic emission of tungsten filaments in a low temperature cell in
the vapor phase with a superfluid helium film covering all surfaces; the other
is operating a glowing filament immersed in bulk liquid helium. We present both
the steady state and rapid sweep I-V curves and the electron current yield.
These curves, having a negative dynamic resistance region, differ remarkably
from those of a vacuum tube filament. A novel low temperature vapor-phase
electron collector for which the insulating helium film on the collector
surface can be removed is used to measure emission current. We also discuss our
achievement of producing multi-electron bubbles (MEBs) in liquid helium by a
new method.
