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Nuclear physics and Roman archaeology just don’t mix, or so you would think. But researchers at the National Institute of Nuclear Physics in Padua, Italy, and a team of archaeologists have found a common goal: to raise 1500 ingots of lead from a Roman freighter which sank off the coast of Sardinia more than 2000 years ago.

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The physicists want the ancient lead for a practical reason. Lead is the best material for shielding delicate experiments which detect minute amounts of radiation, for example from the unusual kinds of radioactivity associated with double beta decay, or from the rare interaction of neutrinos – the ghost-like particles that are emitted from the Sun and pass through the Earth unheeded. Another experiment requiring shielding is the detection of particles of so-called dark matter – the material believed to hold the Universe together.

Such experiments are usually carried out deep underground in specially built installations, such as the Gran Sasso Laboratory near Rome. Here, 1400 metres of solid rock protect the detecting apparatus from high-energy cosmic rays raining through the atmosphere. Small amounts of radioactive materials in the rocks themselves, however, can interfere with the experiments, so the detector has to be surrounded by an additional lead shield.

Commercial lead has only tiny amounts of radioactive contaminants such as lead-210, but even this is enough to affect very sensitive experiments. However, the half-life of lead-210 is 22 years, which means that lead excavated a long time ago would have lost most of its radioactive component. In fact, physicists have sometimes relied on lead from old cannonballs for their experiments.

Lead that is 2000 years old would be expected to contain virtually no radioactive isotopes at all. The physicists, when they tested a small portion of a salvaged ingot, found this was the case.

Full Article: NewScientist

This article is rather old, but was just put online by NewScientist. Being able to detect neutrinos is very hard even for sophisticated equipment that we have today. I know of some facilities that use very sensitive equipment at the bottom of large water basins deep beneath the Earth, yey very few neutrinos are even detected. It is kind of neat to see old wreckage being put into use for current scientific research. There wasn’t any follow up article shown, but it would be interesting to find out whether or not this lead helped them in any way. If anyone knows of any further research, I’d love to hear it.