Particle Physics Experiment Will Use Ancient Lead From a Roman ShipwreckThe cargo from a Roman ship sunk off the coast of Sardinia more than 2,000 years ago will finally be put to use–it will become a shield for a neutrino detector. In Italy, 120 lead bricks recovered from the shipwreck will soon be melted to make a protective shield for Italy’s new neutrino detector, CUORE (Cryogenic Underground Observatory for Rare Events).
The ancient lead, which is useful because it has lost almost all traces of its natural radioactivity, has been transferred from a museum in Sardinia to the national particle physics laboratory at Gran Sasso. After spending two millennia on the seabed, the lead bricks will now be used in an experiment that will take place beneath 4,500 feet of rock.
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To create this shield, scientists need lead. But freshly mined lead is slightly radioactive and contains an unstable isotope. This isotope, lead-210, gradually decays into more stable isotopes after it’s extracted from the ground; its concentration halves every 22 years. That’s why physicists are so interested in old lead. As CUORE scientist Ettore Fiorini told Nature:
“It is not unusual for particle physicists to go hunting for low-radioactivity lead,” he says. “Metal extracted from roofs in antique churches or from keels of wrecked ships has often been used in experiments.”
So when the Roman shipwreck was discovered in 1988 and was found to be full of lead ingots, scientists were thrilled–they would have access to lead whose radioactivity had substantially diminished over the centuries, and the quantity would allow them to fashion a shield more than an inch thick.
Now that's kinda cool.