PMTs in LUX, over floor in MJD

The shift from outfitting the Davis Campus to installing the experiments was in full swing last week for both science collaborations, the Large Underground Xenon (LUX) detector and the Majorana Demonstrator experiment.

Researchers installed 16 photomultiplier tubes (PMTs) in the LUX detector's large water tank. The PMTs will detect faint, telltale flashes of light, called Cherenkov radiation, left by the few muons hardy enough to penetrate nearly a mile of rock to LUX. Nothing travels faster than the speed of light in a vacuum, Science Liaison Director Jaret Heise reminds us, but light slows down in water. Charged particles such as muons, can exceed the speed of photons in water, leaving a sort of photonic shock wave that is named for Nobel Laureate Pavel Alekseyevich Cherenkov.

In the nearby Transition Area, Majorana collaboration members and SDSTA staff were working on a number of projects, including the installation of the "over floor" base that will support the Majorana Demonstrator detector and its heavy lead shielding. Plastic scintillators inserted between the beams of the over floor will provide a "veto" signal similar to the veto signals from the PMTs in the LUX tank that is, they will warn researchers to ignore signals generated by bogus events.