Faraday cup

Named after English scientist Michael Faraday (1791–1867), who first theorized ions around 1830.

Faraday cup (plural Faraday cups)

1. A conductive metal cup designed to catch charged particles in vacuum.
   • 1996, IBM Journal of Research and Development, Volume 40, International Business Machines Corporation, page 74:

     The inner cylinder of the Faraday cup is electrically connected to the brass plug, and is the electrically active part of the unit.

   • 2007, Sabine Becker, Inorganic Mass Spectrometry: Principles and Applications, Wiley, page 103:

     In many mass spectrometers for electric ion detection a Faraday cup is generally used today for the direct and accurate measurement of ion currents of separated ion beams, especially if relatively high ion currents are to be measured.

   • 2014, Lothar Rottman et al., “Chapter 4: Technical Background”, in Thomas Prohaska, Johanna Irrgeher, Andreas Zitek, Norbert Jakubowski, editors, Sector Field Mass Spectrometry for Elemental and Isotopic Analysis, Royal Society of Chemistry, page 88:

     Faraday cups are the detectors of choice for precise and accurate isotope ratio measurements.