Exports of this piece of equipment were low, however, and EMI left this area of product manufacture. Alan Blumlein, an engineer employed by EMI, conducted a great deal of pioneering research into stereo sound recording many years prior to the practical implementation of the technique in the early 1950s. He was killed in 1942 whilst conducting flight trials on an experimental H2S radar set. During and after World War II, the EMI Laboratories in Hayes, Hillingdon developed radar equipment (including the receiver section of the British Army's GL-II anti-aircraft fire-control radar), microwave devices such as the reflex klystron oscillator (having played a crucial role in the development of early production types following on from the British Admiralty Signal School's pioneering NR89, the so-called "Sutton tube"), electro-optic devices such as infra-red image converters, and eventually guided missiles employing analogue computers. The company was also for many years an internationally respected manufacturer of photomultipliers. This part of the business was transferred to Thorn as part of Thorn-EMI, then later became the independent concern Electron Tubes Ltd. The EMI Electronic Business Machine, a valve and magnetic drum memory computer, was built in the 1950s to process the British Motor Corporation payroll. In 1958 the EMIDEC 1100, the UK's first commercially available all-transistor computer, was developed at Hayes under the leadership of Godfrey Hounsfield, an electrical engineer at EMI. In the early 1970s, with financial support by the UK Department of Health and Social Security as well as EMI research investment, Hounsfield developed the first CT scanner, a device which revolutionised medical imaging. In 1973 EMI was awarded a prestigious Queen's Award for Technological Innovation for what was then called the "EMI scanner", and in 1979 Hounsfield won the Nobel Prize for his accomplishment. After brief, but brilliant, success in the medical imaging field, EMI's manufacturing activities were sold off to other companies, notably Thorn (see Thorn EMI). Subsequently, development and manufacturing activities were sold off to other companies and work moved to other towns such as Crawley and Wells. Emihus Electronics, based in Glenrothes, Scotland, was owned 51% by Hughes Aircraft, of California, US, and 49% by EMI. It manufactured integrated circuits electrolytic capacitors and, for a short period in the mid-1970s, hand-held calculators under the Gemini name.