  The XENON experimental program aims to detect cold dark matter particles via
their elastic collisions with xenon nuclei in two-phase time projection
chambers (TPCs). We are currently testing a new TPC at the 100 kg scale,
XENON100. This new, ultra-low background detector, has a total of 170 kg of
xenon (65 kg in the target region and 105 kg in the active shield). It has been
installed at the Gran Sasso Underground Laboratory and is currently in
commissioning phase. We review the design and performance of the detector and
its associated systems, present status, preliminary calibration results,
background prediction and projected sensitivity. With a 6000 kg-day
background-free exposure, XENON100 will reach a sensitivity to spin-independent
WIMP-nucleon cross section of 2e-45 cm2 by the end of 2009. We also discuss our
plan to upgrade the XENON100 experiment to improve the sensitivity by another
order of magnitude by 2012.
