The Yates Shaft headframe, left, behind the Yates Administration Building.

The LZ dark matter experiment operates at the Sanford Underground Research Facility (SURF) in Lead, South Dakota. SURF is located at the former Homestake gold mine and has laboratory spaces nearly a mile underground. SURF hosts a number of scientific experiments that require underground operation in order to reduce the cosmic ray background. 

Current and future experiments at Sanford Lab (SURF)

Following construction in a dedicated Surface Assembly Laboratory, LZ was installed in the Davis Laboratory 4,850 ft underground (nearly a mile), to radically lower the backgrounds in the experiment from cosmic rays. The Davis Laboratory is the same site that housed Ray Davis’ Nobel Prize-winning neutrino experiment. The laboratory was occupied by the LUX experiment until 2016.

Physicists working on LZ sub-systems the Davis Laboratory nearly a mile underground at SURF.

LZ is housed in an 8 meter diameter by 6 meter high water shield containing 70,000 gallons of purified water and a mammoth scintillator detector encasing the inner xenon detector holding 7 tonnes of purified target. The water shield and outer detector reduces external background signals to the xenon detector, in particular neutrons and gammas. The water shield will also be instrumented with photomultiplier tubes to detect the Čerenkov radiation from cosmic muons.

The LZ water shield, holding the inner xenon detector and a surrounding liquid scintillator outer detector.