super stem uk

A laboratory in Daresbury hosts some of Europe’s most powerful microscopes

Some of the most powerful microscopes in the UK can be found in the countryside town of Daresbury, Cheshire. It’s home to the UK National Facility for Advanced Electron Microscopy is funded by the Engineering and Physical

Sciences Research Council (EPSRC). Here, researchers from all over the world come together to use the powerful microscopes that are kept at the facility. The newest model is the Nion ULTRASTEM 100MC ‘HERMES’, also known as SUPERSTEM 3, but the institute also houses the older models Nion ULTRASTEM 100 (SUPERSTEM 2) and the VG HB501 microscope equipped with a Mark II Nion Cs corrector (SUPERSTEM 1).

These microscopes are a specialised type of TEM called scanning transmission electron microscopes (STEM), however, the ‘HERMES’ microscope can be used as a conventional transmission electron microscope (CTEM) as it is fitted with additional scanning coils to allow it to switch between different modes. The STEM machines produce images by using a focused beam of electron that scans across a thin sample in a raster pattern (horizontal, almost overlapping lines across a rectangular shape). The machines are so high resolution that they require an incredibly stable environment free from vibration, temperature fluctuations and electromagnetic and acoustic waves. This sensitivity can be demonstrated by clapping near SUPERSTEM 2. The interference is immediately registered on the computer and jolts the atoms to one side.

While the SUPERSTEM1 requires only a basic level of stability and atmospheric monitoring, the SUPERSTEM 2 is shrouded in a heavy, thick curtain to reduce interference. The SUPERSTEM3 is so sensitive that it must be operated from a separate room.

The SUPERSTEM facility is keen to provide access for the global scientific community. Previous projects include investigating thermoelectric oxides for power generation and looking at molybdenum disulphide, a catalyst used in oil refineries, to remove harmful sulphur impurities in fossil fuels. Researchers from all fields are invited to apply to use the microscopes in small studies free of charge pending review by the scientists at the facility.