title: An apparatus for studying electrical breakdown in liquid helium at 0.4 K and testing electrode materials for the neutron electric dipole moment experiment at the Spallation Neutron Source.
abstract: 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 ∼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 ±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 liquid helium of ρV > 5 × 10(18) Ω 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.
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: T M
authors.initials: TM
authors.lastname: Ito
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Ramsey
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: W
authors.initials: W
authors.lastname: Yao
authors.affiliation: Loomis Laboratory of Physics, University of Illinois, Urbana, Illinois 61801, USA.
authors.forename: D H
authors.initials: DH
authors.lastname: Beck
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: V
authors.initials: V
authors.lastname: Cianciolo
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Clayton
authors.affiliation: Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA.
authors.forename: C
authors.initials: C
authors.lastname: Crawford
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Currie
authors.affiliation: W. K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: B W
authors.initials: BW
authors.lastname: Filippone
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: W C
authors.initials: WC
authors.lastname: Griffith
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: M
authors.initials: M
authors.lastname: Makela
authors.affiliation: W. K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: R
authors.initials: R
authors.lastname: Schmid
authors.affiliation: Department of Physics, Brown University, Providence, Rhode Island 02912, USA.
authors.forename: G M
authors.initials: GM
authors.lastname: Seidel
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Tang
authors.affiliation: Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506, USA.
authors.forename: D
authors.initials: D
authors.lastname: Wagner
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: W
authors.initials: W
authors.lastname: Wei
authors.affiliation: Loomis Laboratory of Physics, University of Illinois, Urbana, Illinois 61801, USA.
authors.forename: S E
authors.initials: SE
authors.lastname: Williamson