  The XENON experiment aims at the direct detection of dark matter in the form
of WIMPs (Weakly Interacting Massive Particles) via their elastic scattering
off Xe nuclei. A fiducial mass of 1000 kg, distributed in ten independent
liquid xenon time projection chambers(LXeTPCs) will be used to probe thelowest
interaction cross section predicted by SUSY models. The TPCs are operated in
dual (liquid/gas) phase, to allow a measurement of nuclear recoils down to
16keV energy, via simultaneous detection of the ionization, through secondary
scintillation in the gas, and primary scintillation in the liquid. Thedistinct
ratio of primary to secondary scintillation for nuclear recoils from WIMPs (or
neutrons), and for electron recoils from background, iskey to the
event-by-event discrimination capability of XENON. A dual phase xenon prototype
has been realized and is currently being tested, along with otherprototypes
dedicated to other measurements relevant to the XENON program. As part of the
R&D phase, we will realize and move underground a first XENON module (XENON10)
with at least 10 kg fiducial mass to measure the background rejection
capability and to optimize the conditions for continuous and stable detector
operation underground. We present some of the results from the ongoing R&D and
summarize the expected performance of the 10 kg experiment, from MonteCarlo
simulations. The main design features of the 100 kg detector unit(XENON100),
with which we envisage to make up the 1 tonne sensitive mass ofXENON1T will
also be presented.
