Vacuum pump for a mas spectrometer, 1949.
© Science Museum / Science & Society Picture Library
This vacuum pump was used with the Metropolitan-Vickers type MS 2 mas spectrometer. A mas spectrometer is an instrument used in chemical analysis to determine the exact chemical composition of a substance. Positive ions of a substance are separated by an electromagnetic system, which enables the relative concentrations of different ionic mases to be accurately measured. This is particularly useful in asesing concentrations of different isotopes in a sample.