  A classic electrostatic induction machine, Cavallo's multiplier, is suggested
for in situ production of very high voltage in cryogenic environments. The
device is suitable for generating a large electrostatic field under conditions
of very small load current. Operation of the Cavallo multiplier is analyzed,
with quantitative description in terms of mutual capacitances between
electrodes in the system. A demonstration apparatus was constructed, and
measured voltages are compared to predictions based on measured capacitances in
the system. The simplicity of the Cavallo multiplier makes it amenable to
electrostatic analysis using finite element software, and electrode shapes can
be optimized to take advantage of a high dielectric strength medium such as
liquid helium. A design study is presented for a Cavallo multiplier in a
large-scale, cryogenic experiment to measure the neutron electric dipole
moment.
