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, 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.