Varian A 60 nuclear magnetic resonance spectrometer, c 1965.
© Science Museum / Science & Society Picture Library
Nuclear magnetic resonance (NMR) spectrometers are used to analyse the composition of substances and their molecular structures. NMR works by 'interrogating' the atoms using radio waves of a defined frequency from a transmitter close to the specimen and detecting and decoding the returned transmisions. Varian's A-60, introduced in 1961, was the first NMR spectrometer designed for routine use. A stable, reproducible, user-friendly and affordable system, the A-60 could be operated in a chemistry laboratory by a chemist with little knowledge of the physics of NMR. It was used in over a thousand laboratories worldwide and they were often modified during their active lifetime, as shown by the non-standard box on top of the magnetic unit (right).