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By Nancy Hopkins on

Diamonds are for…scanning?

Diamonds aren’t just a girl’s best friend. They’ve got an amazing range of properties that make then useful for all sorts of stuff.

Ahead of our diamond themed Pi: Platform for Investigation on Saturday 25 August we investigate alternative uses for the wee sparklers…

The author of this blog regularly bathes in diamonds, just like Britney

MEDICAL IMAGING

There are fewer things in life more stunning than a flawless diamond. The fire and sparkle they give off is second to none and it’s no surprise that flawless or near flawless diamonds can cost a small fortune.

However, recent research has revealed that when it comes to using diamonds for medical use, flawless just doesn’t cut it.

Researchers in the Department of Energy’s Lawrence Berkeley National Laboratory at The University of California, Berkley have been working on ways to reduce the huge costs associated with the manufacture of MRI scanners and have found that imperfect diamonds might hold the answer.

Imperfect diamond. Good for science, bad for bling

 

How does an MRI scanner work?

MRI machines are highly specialised bits of kit that uses radio waves and super strong magnets to scan and create detailed images of the human body. The more powerful the magnet, the better it is at scanning. It’s also more expensive.

The human body has natural magnetic properties, and the nucleus of a hydrogen atom acts like a weak compass needle. We’re made up of a lot of water and fat, which contain hydrogen.

When in the presence of a strong magnetic field, the hydrogen nuclei in the body will align themselves. The MRI scanner adds in radio waves, which cause the hydrogen nuclei to resonate. Removing the radio signal causes the atoms to return to their equilibrium state and emit a radio signal of their own.

The scanner picks up on this signal and uses it to map the distribution of molecules with lots of hydrogen atoms. By mapping the vibrating hydrogen, the machine can create detailed images of the human body.  Clever stuff, eh?

How will diamonds make MRI scanners cheaper?

The researchers at Berkley have been working with nanoscale and microscale diamonds and have developed a new technique with the diamonds using spin polarization.

As we’ve already discovered, MRI scanners use magnets to pinpoint mass and atoms. These magnets are bulky and expensive but scientists have discovered that the defects in diamonds can be polarized, a bit like setting a compass.

Scientists zapped the diamonds with green laser light, subjecting it to a weak magnetic field. They then swept across the diamonds’ surface area with microwaves, creating a more uniform spin polarisation (diamonds naturally form in a variety of orientations).

These “hyperpolarized” spins could lead to sharper, more defined images being produced by MRI scanners as the technique significantly improves polarization compared to today’s devices.  They could also drastically reduce the cost of MRI scanners.

How much does an MRI scanner cost?

A brand new, top of the range scanner costs around £2.3m.

At the last count, there were 467 in the UK, most of which are in NHS hospitals. Which often means a long wait for a scan.

Whilst medical imaging diamonds won’t look as jazzy as Nelly’s grill, if they can bring down the cost of MRI scanners and get more people scanned for life threatening conditions, that’s a (glittery) thumbs up from us.

Nelly’s grill. No good for an MRI scanner

 

TURNING YOUR REMAINS INTO A LASTING KEEPSAKE

As we’re all basically made of carbon (18% carbon, to be precise) turning your loved one into a diamond isn’t as outlandish as you might think. There are plenty of companies out there who will take the remains of your beloved and synthesise them into a diamond under laboratory conditions.

It takes around 500g of ashes to create a diamond. The carbon from the hair or ashes of the deceased is extracted from the sample and purified from contamination, making the sample around 99% carbon.

The other 1% contains impurities like boron, an element grows bone, heal wounds, and regulates the immune system. Boron colours the rare blue diamonds found in nature, so many memorial diamonds actually come out looking a bit blue.  As boron and carbon share very similar weights and properties, it’s almost impossible to separate the two.

Interestingly, if the deceased had had chemotherapy the diamonds tend to come out lighter, as chemotherapy strips the body of boron.

A blue diamond, coloured by boron

The mixture is put into a growing cell with a tiny diamond to help the carbon crystallise into a rough shape. The tiny diamond provides a “blueprint” for the carbon to work from, which means the new diamond that eventually forms will require less cutting and polishing.
The final purification step converts the carbon into slippery sheets of graphite — the same type of carbon in pencils. Graphite’s microscopic flat sheets of carbon are an ideal starter material for synthesizing diamonds.

Natural diamonds form over billions of years from layers of carbon that get stuck in lava tubes about a mile deep into the Earth’s crust. This is a very pressurised, very hot environment that compresses the carbon and heats it up to such an extent that it forces a permanent change in the material. So how to do this in a lab?

The carbon is put into a high-temperature high-pressure growing machine. The carbon is heated to around 1371 degrees Celsius and is under 395,000 kg of pressure.

That’s a lot of pressure!

It usually takes around 6-8 weeks for a diamond to form, inside a chunk of graphite. The folks in the lab then crack open the graphite and voila….a rough, uncut diamond ready to be polished and set into an everlasting keepsake.

 

BATTERIES

Danger, danger…high voltage! Researchers at the University of Bristol have developed a method to turn radioactive graphite blocks, a waste product of nuclear reactors, into artificial diamonds that generate electricity. Nuclear reactors generate heat from highly radioactive uranium rods. The rods are placed in blocks of graphite to control the heat flow and nuclear reactions.

After years of absorbing nuclear radiation, the graphite blocks become highly radioactive and when nuclear power plants are decommissioned, the graphite blocks need to be disposed of.
Nuclear waste takes thousands of years to stop being radioactive, and safely storing the nuclear waste can be problematic.

Scientists at the Cabot Institute in Bristol discovered that by heating the carbon blocks, a lot of the radioactive carbon is given off as a gas (carbon 14) which is collected and then converted into diamonds at low pressures and elevated temperatures.

These small, man made diamonds can generate a small current when placed in a radioactive field.  However as the diamonds themselves are made of radioactive carbon, they are able to provide their own energy.

Sounds a bit, um, dangerous

To be used safely, a non-radioactive diamond layer is created around the radioactive diamond. As diamond is such a tough substance, casing the radioactive diamond in a layer of non-radioactive diamond means that the radiation emissions are super low and emit about as much radiation as a piece of fruit.

The diamond batteries have an incredible battery life, lasting around 5,000 years making them perfect for situations where replacing batteries isn’t so simple – bio technology or in space. Plus they’d be GREAT at festivals for charging your phone.

However there’s just one snag – the current power in these batteries is pretty low at the moment. One battery containing 1g of carbon-14 would deliver around 15 joules a day, which is less than an AA battery. So you’d need a fair few of them to power your car or cook your Christmas dinner.

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