Researchers at Swansea University have developed a new method for neutral atomic beam microscopes that could significantly speed up the process of obtaining microscope images. These microscopes are used to image delicate samples that cannot be studied using commercially available microscopes, such as bacterial biofilms and organic photovoltaic devices. They work by scattering a beam of low energy neutral particles, usually helium atoms, from a surface to image its structure and composition.
The current method of obtaining images using neutral atomic beam microscopes involves illuminating the sample through a microscopic pinhole and scanning its position while recording the scattered beam to build an image. However, this method is time-consuming as the image is measured one pixel at a time. Reducing the pin-hole dimension to improve resolution results in a significant decrease in beam flux and requires even longer measurement times. The new method developed by Swansea University researchers aims to address this limitation and provide engineers and scientists with faster results when scanning samples.
The Swansea University research group, led by Professor Gil Alexandrowicz from the chemistry department, developed a faster alternative method to pinhole scanning. This method involves passing a beam of atoms through a non-uniform magnetic field and using nuclear spin precession to encode the position of the beam particles that interact with the sample. The team demonstrated the effectiveness of this method using a beam of helium-3 atoms, a rare light isotope of regular helium.
Morgan Lowe, a PhD student in the Swansea team, built the magnetic encoding device and conducted the first set of experiments to demonstrate the new method. The beam profile measured by Mr. Lowe closely matched numerical simulation calculations, showing the potential of the new magnetic encoding method to improve image resolution with a smaller increase in time compared to the current pin-hole microscopy approach. Professor Gil Alexandrowicz noted that the new method opens up various opportunities in the field of neutral beam microscopy, including the potential for enabling new contrast mechanisms based on the magnetic properties of the sample being studied.
In the immediate future, the Swansea University research team plans to further develop the new method to create a fully working prototype magnetic encoding neutral beam microscope. This will allow for testing of the resolution limits, contrast mechanisms, and operation modes of the new technique. In the long run, the aim is to make this new type of microscope available to scientists and engineers for characterizing the topography and composition of sensitive and delicate samples they produce or study. This advancement could greatly benefit researchers by providing faster results when scanning samples that are difficult to image or affected by electrons, ions, and photons.