Room Temperature Test of the Full Scale Cryogenic Cavallo High Voltage Multiplier for nEDM@SNS

The SNS nEDM experiment, a search for an electric dipole moment of the neutron to be conducted at the Oak Ridge National Laboratory Spallation Neutron Source, will employ a strong electric field across measurement cells immersed in superfluid helium-4 at 400 mK. The voltage required on a central electrode is about 650 kV. Direct supply of such a voltage from a room temperature power supply into the sub-1 Kelvin environment would be very difficult in terms of cryogenic compatibility, so this experiment aims to use concepts from 18th century Cavallo's Multiplier to amplify a moderate supply voltage up to a sufficient level. A cryogenic Cavallo high voltage amplifier is being developed at Los Alamos National Laboratory for use in the SNS nEDM experiment. In this talk, results from testing this apparatus at room-temperature, prior to its installation in a cryostat for low temperature testing, will be presented.