Ancient lead ingost, each weighing about 33 kilograms, come from a Roman shipwreck, the remains of a vessel that sank between 80 B.C. and 50 B.C. off the coast of Sardinia. What makes the ingots equally valuable to physicists is the fact that over the past 2,000 years their lead has almost completely lost its natural radioactivity. It is therefore the perfect material with which to shield the the CUORE (Cryogenic Underground Observatory for Rare Events) detector, at the Gran Sasso laboratory (INFN). An effort to determine the Majorana/Dirac nature of the neutrino. Today, the last load of 30 lead ingots departed from Cagliari, destination Gran Sasso.
There were about a thousand ingots of 33 kg each extracted in a campaign of diving expeditions funded by INFN. Each of the lead ingots has a unique stamp that records some of its manufacturing history: the name of the Roman who cast it. These inscriptions are priceless archeological sources, and are being studied at the National Archaeological Museum in Cagliari, Sardinia.
Andrea Mameli, blog Linguaggio Macchina, 18 Jan. 2016