Original URL: http://www.theregister.co.uk/2012/11/22/lux_flooded/
WIMP-seeking detector flooded
It’s okay, that’s what’s meant to happen
A South Dakota-based dark matter experiment has taken a large step towards go-live, with a detector lowered into its water tank ahead of observations beginning next year.
The Large Underground Xenon (LUX) detector was delivered in July. The underground location is designed to shield the detector from cosmic radiation, while the water tank is there to filter out the small amounts of natural radiation emitted by the surrounding rock.
The 6m x 7.6m (25 feet in diameter, 20 feet tall) tank is filled with “ultra-pure, de-ionized water”, which El Reg supposes caused a distressing price hike for hipsters who won’t drink anything but.
Scientists operating LUX hope it will be sensitive enough to detect WIMPs, theorised as one of the explanations for the Universe’s missing mass (around 80 percent of the matter calculated to exist hasn’t been observed yet).
Twenty photo-multiplier tubes, each sensitive enough to detect a single photon, line the water tank. Their job is to provide error correction: should a high-energy particle make it all the way through the rock and water, its tiny flash of light will correspond with a collision event in LUX, alerting scientists to disregard a non-WIMP interaction.
LUX itself is installed in a cryostat at -160°F, with another 122 photo-multiplier tubes to detect WIMP interactions. If collisions between WIMPs and Xenon atoms take place, scientists expect to see two flashes of light, one at the point of impact and a second in a layer of Xenon gas at the top of the detector.
More information about the LUX Dark Matter Collaboration can be found here. ®