Tiny Crystals, Big Difference

Imagine lying inside a hospital scanner for 45 minutes — now imagine that cut to 15. That’s the real improvement patients at London’s Royal Brompton Hospital have seen after the installation of a new imaging machine that uses cadmium zinc telluride, or CZT. The semiconductor, produced in the UK by firms such as Sedgefield-based Kromek, is helping machines create sharper, three‑dimensional images while needing less radioactive tracer. Clinicians say the picture quality is markedly better and the scanner’s sensitivity allows tracer doses to be trimmed by around 30%, easing the burden on patients. CZT works very differently from older detectors. When an X‑ray or gamma photon hits the crystal it creates an electrical signal in one step, keeping precise information about timing and energy. That single conversion lets technicians build spectroscopic or “colour” images and pick out finer details — useful when doctors search for tiny blood clots in lungs or a pulmonary embolism. Making CZT is far from simple. Inside Kromek’s factory dozens of small furnaces — around 170 by the company’s account — heat a special powder until it melts and then carefully solidifies into a single crystal. The weeks‑long process aligns atoms into a uniform lattice; the result behaves like a highly specialised light sensor, rather like the image chips in a smartphone but tuned to high‑energy photons. The material’s uses stretch beyond hospitals. CZT detectors are already deployed in some airport systems for explosives detection and to scan checked baggage in parts of the US, and firms expect the technology to move into hand luggage screening in future. Astronomers and physicists prize CZT too: space and balloon‑borne X‑ray telescopes use very thin pieces to reduce background noise, and major facilities such as the Diamond Light Source are choosing CZT detectors for upgrades that will produce far brighter X‑rays. But supply is tight. Only a handful of organisations can manufacture CZT at scale and many research teams struggle to obtain the exact thickness or detector structure they need. One US university scientist seeking wafer‑thin detectors found it hard to source them and said he may reuse older parts or switch to a different material. At the same time, facility upgrades and space missions depend on reliable access to these crystals. Small, finicky and expensive to grow, CZT is a niche material with outsized impact — shortening scans, cutting doses, strengthening security and enabling cutting‑edge science. Britain’s modest manufacturing footprint in this field now plays a quietly central role in technologies people use every day and in experiments happening at the edges of knowledge. --- Managing your business finances? TaxAce provides smart online accountancy services for UK businesses with flexible monthly plans. Image and reporting: https://www.bbc.co.uk | Read original article