Helium microscope for imaging delicate structures gains funding

A new type of microscope for non-destructive imaging of delicate structures is to be developed by the University of Liverpool QUASAR group, based in the Cockcroft Institute, with spin-out company D-Beam. The Quantum Gas Jet-based Helium Atom Microscope (qHAM) has gained funding from Innovate UK as part of the national strategy to commercialise quantum technologies; it builds on ground-breaking work by the team on beam diagnostics.

Professor Carsten Welsch, Head of the Department of Physics at the University of Liverpool and a senior academic at the Cockcroft Institute, explains that scanning helium microscopy (SHeM) offers many benefits over the use of x-rays or charged electrons, which can destroy fabrics, biological samples and organic films, and present difficulties when using magnetic fields.

He says: “Neutral helium beams provide a chemical, electrical and magnetically inert surface probe that delivers no charge to the sample. This creates the opportunity to image fragile structures without damaging them.”

SHeM takes helium gas, pumps it to high pressure and allows it to expand through a tiny hole into a vacuum. The helium atoms are back scattered from the sample, giving a higher resolution than optical microscopy, and the range of scattering pathways creates contrast within the image.

Professor Welsch continues: “Although scanning helium microscopy has been available for a number of years, neither a focussed beam of sufficient energy or detectors that are capable of capturing the scattering mechanisms behind the image contrast have yet been developed.

“A key challenge is maximising the intensity of the imaging beam to overcome noise, while minimising its width, which provides the resolution. This is achieved by creating a supersonic expansion of gas in a vacuum that accelerates the helium atoms to high velocities.”

“The QUASAR Group in collaboration with our partners at CERN and GSI has already developed a super-sonic gas jet beam monitoring technology for the High Luminosity upgrade of the Large Hadron Collider, and we will be building on this knowledge to develop the quantum microscope.”

Quantum Technologies is one of the areas of strategic importance identified by the Innovate UK Industrial Strategy Challenge Fund. qHAM is based on two quantum phenomena: wave matter duality (quantum objects can act as waves or particles simultaneously) and wave-matter interference (the diffraction pattern can be used to identify the location of the particle).

In this project, fundamental research by the QUASAR Group will be commercialised by D-Beam, a company co-founded by Professor Welsch to fast-track the benefits of scientific breakthroughs to industry.

He explains that the synthetic biology and the organic and polymer electronics industries will be among those to benefit from the technology.

He says: “The aim is to create a compact, low-cost table-top microscope with superior imaging qualities that will enable critical proof-of-concept studies, unlocking the potential of this exciting new approach to imaging.”