The part of the mass spectrometer used for sample ionization, since only particles which carry an electric charge can be analysed in a mass spectrometer. A variety of ion sources are in common use, each designed to ionize a specific class of atom or molecule.
See also:
APCI,
API,
electron ionization (EI), chemical ionization, electrospray ionization, thermal ionization, plasma ionization etc.
The term "ion source" was found in the following pages: