  We have constructed an apparatus to study DC electrical breakdown in liquid
helium at temperatures as low as 0.4 K and at pressures between the saturated
vapor pressure and $\sim$600 torr. The apparatus can house a set of electrodes
that are 12 cm in diameter with a gap of $1-2$ cm between them, and a potential
up to $\pm 50$ kV can be applied to each electrode. Initial results
demonstrated that it is possible to apply fields exceeding 100 kV/cm in a 1 cm
gap between two electropolished stainless steel electrodes 12 cm in diameter
for a wide range of pressures at 0.4 K. We also measured the current between
two electrodes. Our initial results, $I<1$ pA at 45 kV, correspond to a lower
bound on the effective volume resistivity of LHe of $\rho_V > 5\times10^{18}$
$\Omega\cdot$cm. This lower bound is 5 times larger than the bound previously
measured. We report the design, construction, and operational experience of the
apparatus, as well as initial results.
