China's PandaX Project Looks For Dark Matter In the Heart of a Marble Mountain 62
the_newsbeagle writes "Chinese engineers love their superlatives: Biggest dam, fastest train, etc etc. Now they've constructed the deepest underground dark matter detector beneath a mountain in Sichuan province. Such dark matter seekers have to be buried deep to shield them from cosmic rays, because that radiation would be picked up by the detector and could be confused for radiation generated by dark matter. Other dark matter detectors are similarly subterranean: LUX, in the United States, is at the bottom of an abandoned mine in South Dakota, and a European effort called XENON lies below the Gran Sasso mountain. The Chinese researchers hope their PandaX detector will finally reveal the much-hypothesized, never-seen dark matter particles known as WIMPs."
Re:A Marble mountain? A mountain made of marble? (Score:4, Interesting)
I know that the detector tank in the bottom of Homestake is lead shielded, but that lead is very old, no newly mined lead in it. It had to be at least 100 years old to even be considered for recycling into that shielding. I used to live in Rapid City in the '60's, even have a wife I still miss buried there, but in those years, Homestake, 50 miles away in Lead, SD was an actively producing gold mine. And environmental disaster as it struggled to remain profitable, it eventually had to close, and I am glad that another use has been found for its extended underground.
The Lead/Deadwood area tried to survive on tourists, but I imagine much of that allure has faded after the state raided and closed the Pink Lady in the '70's, the countries oldest continuously operated whorehouse. The girls were clean, checked daily to keep them that way, and they contributed 5 to 7 million a year to the local charities. When they had the liquidation sale, somebody wanting a piece of history had to bid $50,000 just to get the front door. End of an era as it had been there, a fully functioning, locally respected member of the community for over 140 years. I felt a little sad at the passing of a legend.
Cheers, Gene