Turning Electrons into Opportunities

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The phrase 'particle accelerator' tends to be synonymous with images of mile-upon-mile of underground tunnels and complex machinery, thanks mostly to the highly publicised opening of the Large Hadron Collider at CERN in Geneva. But not all particle accelerators are the same. In fact, there are more than 20,000 particle accelerators in use today performing tasks ranging from probing the structure of matter to treating cancer.

Given the variety of applications, size really does matter when it comes to particle accelerators. That’s why a table-top particle accelerator being developed by researchers at the University of Strathclyde is one to watch. This remarkable device goes by the name of a laser-plasma wakefield accelerator (LWFA) and accelerates particles over a few centimetres, rather than kilometres. While that name may seem complex, it is certainly worth remembering as the device produces very high quality beams of light or particles that could be transformative in many industries. 

To achieve this immense feat of miniaturisation, Dino Jaroszynski and his team fire extremely short pulses of laser light into a hot gas known as a plasma. As these intense pulses of light pass through the plasma, they create a wake wave. Small bunches of electrons confined to a tiny region only a tenth of the thickness of a human hair within the plasma then surf down this wake wave and rapidly acquire momentum, just like a surfer catching a wave to accelerate forward.

Thanks to the group’s tremendous understanding of this complex process, it can make the LWFA emit either pulses of electrons or light at a vast range of specific wavelengths in highly directional beams. This flexibility is what makes Jaroszynski’s system so appealing to many different applications. 

The challenge facing the team now is how to take its laboratory-based system and tailor it to meet the specific demands of real-world applications, and this is where funding provided by the EPSRC under its Pathways to Impact programme will prove invaluable. The grant will be used to employ the help of experienced photonics entrepreneurs to ensure that the full commercial potential of the LWFA technology is realised.

“We need to find the most disruptive uses of this technology in future growth sectors by weighing up the performance requirements of possible applications with the capabilities of the Strathclyde technology,” explained Graeme Malcolm, the co-founder and current CEO of M Squared Lasers, who will be assisting with the commercialisation efforts. “One of our first steps will be to expand the current patent portfolio on which to base future commercialisation and revenue generation through licensing, new partnerships and new ventures. We will also produce a roadmap to drive both academic and commercial advancement of this enabling technology.”

Some of the most promising applications of the LWFA are in medicine and health care. One application where the LWFA could make an immediate impact is in the production of the radiotracers that are injected into patients undergoing a PET scan. Although such scans give doctors vital information on how organs in the body are functioning, one factor limiting the widespread adoption of PET is the high running costs of the cyclotrons needed to produce the radiotracers. Another application with huge promise is to use LWFA-derived particles to irradiate and kill tumour cells whilst sparing the surrounding non-cancerous cells, thereby reducing the dose-limiting toxicity observed with other forms of radiotherapy.

“Due to the short half-lives of most radioisotopes, current radiotracers must be produced using a cyclotron in close proximity to the PET imaging facility,” explained photonics entrepreneur John Nicholls. “The half-life of radiotracers based on carbon-11 is just 20 minutes. A LWFA could produce radiotracers on-site in hospitals and has the potential to be an alternative to the expensive and large cyclotrons currently used. Part of our job will be to speak to cyclotron and PET medical equipment manufacturers to explore their interest and potential collaborations, with a view to introducing LWFA technology into the medical environment.”