a device for identifying the kinds of particles present in a given substance: the particles are ionized and beamed through an electromagnetic field and the manner in which they are deflected is indicative of their mass and, thus, their identity.
British Dictionary definitions for mass spectrometer
mass spectrometer
mass spectroscope
noun
an analytical instrument in which ions, produced from a sample, are separated by electric or magnetic fields according to their ratios of charge to mass. A record is produced (mass spectrum) of the types of ion present and their relative amounts
