  In the past decade, dual-phase xenon time projection chambers (Xe-TPCs) have
emerged as some of the most powerful detectors in the fields of astroparticle
physics and rare-event searches. Developed primarily towards the direct
detection of dark matter particles, experiments presently operating deep
underground have reached target masses at the multi-tonne scale, energy
thresholds around 1 keV and radioactivity-induced background rates similar to
those from solar neutrinos. These unique properties, together with demonstrated
stable operation over several years, allow for the exploration of new territory
via high-sensitivity searches for a plethora of ultra-rare interactions. These
include searches for particle dark matter, for second order weak decays, and
the observation of astrophysical neutrinos. We first review some properties of
xenon as a radiation detection medium and the operation principles of
dual-phase Xe-TPCs together with their energy calibration and resolution. We
then discuss the status of currently running experiments and of proposed
next-generation projects, describing some of the technological challenges. We
end by looking at their sensitivity to dark matter candidates, to second order
weak decays and to solar and supernova neutrinos. Experiments based on
dual-phase Xe-TPCs are difficult, and, like all good experiments, they are
constantly pushed to their limits. Together with many other endeavours in
astroparticle physics and cosmology they will continue to push at the borders
of the unknown, hopefully to reveal profound new knowledge about our cosmos.
