XENON10 was an experiment to detect dark matterparticles,
consisting of 15 kg of xenon in an underground tank that
had photomultiplier tubes to detect scintillations due to any interactions
with WIMPs. It was operated in 2006-2007 but detected no
signature of a WIMP interaction.
XENON100 was a follow-on experiment using 165 kg of xenon,
XENON1T was a subsequent follow-on with roughly 3.5 tons,
and XENONnT is a current, further-enlarged effort, which
began in 2020 with roughly 9.5 tons.