Exploding the secrets behind 16th century cannonballs

From left, Dr Sofia Diaz-Moreno, I20 Beamline principal scientist, Dr Eleanor Schofield, head of conservation at the Mary Rose Trust and Hayley Simon, PhD student and below, the instrument used to gauge the corrosion

A cutting edge science experiment to ‘destructively sample’ Henry VIII’s cannonballs in Oxfordshire will reveal the secrets to preserving the 16th century artefacts for future generations.

Remains of the Tudor monarch’s 500-year-old warship The Mary Rose were dredged from the ocean’s depths in 1982 along with 1,200 iron cannonballs.

A ground-breaking project between conservationists from The Mary Rose, University College London and Diamond Light Source, located at the Harwell and Innovation Campus, will sacrifice one per cent of the projectiles to save the rest.

The Mary Rose’s head of conservation, Dr Eleanor Schofield, said: “We have taken just 12 of the cannonballs to investigate different methods of conservation through synchrotron science.”

At the UK synchrotron facility, electrons are sped up to near light speed, producing a light 10billion times brighter than the sun.

Intense beams of X-ray, infrared and ultraviolent light are used to measure the level of corrosion from the chlorine and sulphur in slithers cut from the cannonballs.

PhD student Hayley Simon said: “We use a beam size of 0.4mm which allows us to scan multiple positions on the surface of the samples to see how they’re affected.”

The shots were put into a solution similar to baking soda as soon as they were excavated 30 years ago to remove chlorine.

Cracks appeared in the historically significant artefacts shortly after going on display at the Heritage Lottery funded museum in 2013.

Dr Schofield added: “When the shots are in the sea environment and they’re buried, it’s fine, but when you start to excavate them and they’re exposed to air is when you start to get problems.

“Within months of opening we noticed there were problems and took them all off display and it was pretty much straight after that I started talking to UCL and Diamond.

She said it was an “alarmingly straightforward” process and that “it’s been a dream” to work on the “lovely research project”.

A fraction of Diamond’s £60m operating costs are used to support and enable research in virtually all fields of science.

Around 70 experiments are conducted using the beamlines every six months.

Principal scientist Dr Sofia Diaz-Moreno said regardless of the financial cost, “there’s also a moral duty” to preserve the artefacts for future generations.

“It’s money well spent in my opinion,” she said.

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