Ion source used in a 1990's mass-spectrometer, capable of both electron impact and chemical ionisation; sections visible (from left to right): ion lenses, heated ionisation source chamber, repeller lens; golden yoke provides magnetic field for electron path.
<a href="//commons.wikimedia.org/wiki/User:Fulvio314" title="User:Fulvio314">Fulvio314</a>
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