A few years ago, Carla Raymond was approached with a curious request about a cat.

The Macquarie University student was visiting the Australian Institute of Archaeology when Dr Chris Davey asked her to look at a very unusual artefact.

"He came to me and he said, 'I have this mummified cat and I'm wondering what we can do to see if it is authentic, if it has anything inside the wrappings, if we can learn anything about it. Do you think you can help me?'," Carla recalled.

Carla uses imaging techniques to reveal the secrets of archaeological artefacts thousands of years old.

But this was her first encounter with a mummified cat from ancient Egypt.

"I don't think I realised before I worked on this that they actually mummified animals to such a great extent in Egypt," she said.

"They've mummified millions and millions of animals, as well as humans."

Depending on which god you were hoping to gain a blessing from, you would take the mummified animal and give it as a donation at the temple in exchange for wealth or prosperity.

The mummified cat in question had been brought back to Australia by Sir Charles Nicholson when he returned from Egypt in the 1850s.

It was first part of the Nicholson Collection at the University of Sydney and then part of the Australian Institute of Archaeology collection in Melbourne, but little was known about it.

"Was it actually a cat in the wrappings or was it a different animal altogether?"

Half a cat

Neutron (left) and X-ray (middle) scans provide complementary images of a mummified cat that can be combined into one image (right). ( Supplied: Carla Raymond )

Carla's imaging revealed that the mummified animal was indeed a cat

"[But] it was only the legs and the tail of the back end of a cat," Carla said.

At first she thought this was pretty unusual, but in reading further, found this was actually quite a common practice towards the late period in Egypt, in about 30BC.

"[During] that time there seemed to be an increase in interest in these mummified animals," she said.

"And because there was such a demand from the public, they were having trouble meeting that in their production.

"It seems that half a cat's as good as a whole cat. As long as it's got some part of the cat in it, it seemed to be deemed as worthy to be sold at the temple."

From mummified cats to ancient real estate deals

This clay envelope and enclosed tablet detail a land transaction, but not all ancient texts were so polite. ( Supplied: Joseph Bevitt )

Carla has also used imaging techniques to unravel the mysteries of an artefact covered in cuneiform writing, which is one of the oldest scripts in the world.

The clay tablet was found inside a clay envelope from ancient Mesopotamia — which stretched across what is today Turkey, Syria, Iran and Iraq — from around 3000BC.

This artefact was first discovered in 1953 by the British archaeologist Sir Max Mallowan and his wife, author Dame Agatha Christie.

The envelope was covered in writing, but Carla and her colleagues suspected that wasn't the only script they could discover.

"We thought maybe there might be a tablet on the inside because this is sometimes what you find," Carla said.

"I've been working with X-rays and neutron imaging to have a look at what's on the inside of this, and see if we can read the hidden texts that are inside."

The text inside documented a land transaction.

"It was detailing a small package of land, how much the loan would be to buy that property, and then how long they would have the loan for," Carla said.

"There were a number of witnesses that were mentioned in the document. And then on the envelope outside there was two seals from the authority figure who oversaw this arrangement."

Composite image of the external surfaces of the clay envelope and the enclosed clay tablet. ( Supplied: Carla Raymond )

Despite the formality of this document, not all the ancient texts that have been discovered are so polite.

"Some of the documents that have been found are legal documents, some are epic stories, but in some cases it's just correspondence between friends or a customer complaint even at times," Carla said.

"Maybe something like, I paid this much for two sheep or a cow and I think that this person ripped me off."

Some of these complaints were sent while others were hidden away until their discovery by archaeologists, like an angry note you write and never send.

Studying artefacts in a non-destructive way

Carla and her colleagues are now trying to unravel the secrets of an obscure lead scroll. ( Supplied: Joseph Bevitt )

The beauty of the X-ray and neutron imaging techniques that Carla uses to study these artefacts is that they don't damage the objects in any way.

"We don't have to alter the structure or the outside of the object at all, we can preserve it and still learn a lot about it," she said.

And by using both X-rays and neutrons she can get complementary images of what she's looking at, because they pass through materials differently.

"X-rays tend to move through soft materials very easily, and they show us more dense materials like bones or metals," Carla said.

"Neutrons can go straight through [denser materials like lead or stone] but are actually blocked by water."

When they scanned the mummified cat, the X-rays showed the bones and a small maybe metal amulet that was on the inside of the wrapping.

Whereas the neutron scans allowed them to see the wrapping of the layers of fabric really clearly, down to being able to see the coarseness of the threads, and also allowed them to learn a lot more about the mummification technique.

Both techniques allowed her to build a virtual 3D reconstruction of the object, take cross sections through it, and segment out interesting pieces she and her colleagues might be interested in studying in more depth.

"In having these imaging technologies, we're able to study these artefacts without interfering with their intention and respecting that," Carla said.

"It means that we don't have to change … the way the ancient people made these artefacts to be.

"[And] the way that they were made, I like to think that they were intended to stay that way."