Plumbing the Universe for Dark Matter
gawdonblue writes:
This story, from Australia's national broadcaster, details how scientists were keen to use old lead from a ship that sunk in Roman times to shield modern instruments from stray radiation.
When a 2,000-year-old Roman shipwreck was found off the Sardinian coast in 1988, it didn't just thrill archaeologists - physicists were excited too.
The discovery grabbed the attention of one in particular: Ettore Fiorini, a particle physicist with Italy's Institute for Nuclear Physics (INFN).
He didn't care too much about the ship. He was more interested in its cargo - hundreds of lead bars, each weighing 33 kilogrammes.
[...] Ancient lead is useful for sensitive physics experiments because it has lost the radioactivity that can complicate observations.
When trying to observe elementary particles, which are the tiniest building blocks that make up reality, physicists need to silence any background noise.
[...] Lead is a suitable shield from this radioactivity - which can come from cosmic rays or bananas - because it's super dense.
But freshly mined lead has some radioactive "noise" of its own, because it naturally contains a trace amount of the unstable isotope lead-210, which releases energy as it decays.
[...] Which is why, according to metallurgist Kevin Laws of the University of New South Wales, physicists are on the lookout for lead mined during ancient Roman times.
It has had plenty of time to become stable.
"But there is debate that by utilising lead from sources such as shipwrecks we are destroying historical items and record," Dr Laws says.
Read more of this story at SoylentNews.