Luminescence techniques are extensively used in clinical medical testing, and their application in the food and pharmaceutical industries is growing. Well-known examples include HIV testing and inspecting products such as meat and cheese for the presence of antibiotics, drugs, insecticides or bacteria. Luminescence analysis has increasingly replaced conventional techniques, such as colorimetry, fluorometry and methods based on radioactive labels, and offers higher sensitivity and a wider measurement range. Light detection is a key to making these applications work, and the use of a photomultiplier tube in sensitive instrumentation has advantages over other detectors... Meet the author Tony Wright is marketing director at Electron Tubes Ltd. in Ruislip, Middlesex, UK. He has a PhD in high-energy physics from the University of London.