  XENON is a novel liquid xenon experiment concept for a sensitive dark matter
search using a 1-tonne active target, distributed in an array of ten
independent time projection chambers. The design relies on the simultaneous
detection of ionization and scintillation signals in liquid xenon, with the
goal of extracting as much information as possible on an event-by-event basis,
while maintaining most of the target active. XENON is expected to have
effective and redundant background identification and discrimination power,
higher than 99.5%, and to achieve a very low threshold, on the order of 4 keV
visible recoil energy.
  Based on this expectation and the 1-tonne mass of active xenon, we project a
sensitivity of 0.0001 events/kg/day, after 3 yr operation in an appropriate
underground location. The XENON experiment has been recently proposed to the
National Science Foundation (NSF) for an initial development phase leading to
the development of the 100 kg unit module.
