The LZ program consists of two stages of direct dark matter searches using
liquid Xe detectors. The first stage will be a 1.5-3 tonne detector, while the
last stage will be a 20 tonne detector. Both devices will benefit tremendously
from research and development performed for the LUX experiment, a 350 kg liquid
Xe dark matter detector currently operating at the Sanford Underground
Laboratory. In particular, the technology used for cryogenics and electrical
feedthroughs, circulation and purification, low-background materials and
shielding techniques, electronics, calibrations, and automated control and
recovery systems are all directly scalable from LUX to the LZ detectors.
Extensive searches for potential background sources have been performed, with
an emphasis on previously undiscovered background sources that may have a
significant impact on tonne-scale detectors. The LZ detectors will probe
spin-independent interaction cross sections as low as 5E-49 cm2 for 100 GeV
WIMPs, which represents the ultimate limit for dark matter detection with
liquid xenon technology.