Abstract
Abstract
Most search experiments sensitive to quantum chromodynamics
(QCD) axion dark matter benefit from microwave cavities, as
electromagnetic resonators, that enhance the detectable axion signal
power and thus the experimental sensitivity drastically. As the
possible axion mass spans multiple orders of magnitude, microwave
cavities must be tunable and it is desirable for the cavity to have
a tunable frequency range that is as wide as possible. Since the
tunable frequency range generally increases as the dimension of the
conductor tuning rod increases for a given cylindrical conductor
cavity system, we developed a cavity system with a large dimensional
tuning rod in order to increase this. We, for the first time,
employed not only a piezoelectric motor, but also gears to drive a
large and accordingly heavy tuning rod, where such a combination to
increase driving power can be adopted for extreme environments as is
the case for axion dark matter experiments: cryogenic,
high-magnetic-field, and high vacuum. Thanks to such higher power
derived from the piezoelectric motor and gear combination, we
realized a wideband tunable cavity whose frequency range is about
42% of the central resonant frequency of the cavity, without
sacrificing the experimental sensitivity too much.