Faraday Cups

Accurately measure ion beam currents with NEC Faraday cups.

NEC manufactures various types of Faraday cups that are ideal for applications requiring accurate measurement of ion beam intensity in cases where the ion beam diameter is one inch (2.54 cm) or less.



To monitor ion beam currents, NEC offers 3 standard models of Faraday cups: FC18, FC50 and FC28.


Faraday Cup Design

The configuration of NEC Faraday cups varies from model to model dependent upon power rating and application requirements. However, all NEC Faraday cups are equipped with the following features:

NEC provides three standard models of Faraday cups, with custom versions based on any of these designs available upon request. Below are brief descriptions of each model.

Model Beam Power Rating Aperture dia. Features
 FC18 1000W 1.0″ (2.54cm) Highest Power Faraday Cup

  • For applications requiring high energy or high beam currents.
  • Unique tantalum cone design that decreases the effective power density on the tantalum surface to eliminate local hotspots.
  • Indirectly water-cooled cone that allows the use of ordinary tap water.
Faraday Cup model 18
FC50 50W 1.0″ (2.54cm) Faraday Cup for Existing Housings & Maximum Beam Clearance

  • For applications requiring maximum beam clearance when the cup is retracted.
  • Mounted on a single flange with feedthroughs to allow it to be mounted in an existing vacuum chamber.
  • Cooling by radiation only. No water cooling needed.
  • 2″ (50 mm) stroke.
  • Custom insertion lengths and custom housings available.
Faraday Cup model 50
 FC28 100W 0.375″ (0.95cm) Fixed Faraday Cup for Pulsed Ion Beams

  • Designed as a timing device by measuring the coincidence and/or duration of pulsed ion beams.
  • Includes a tungsten grid at the exit of the suppressor assembly to limit the spread of the delivered pulse, which is affected by the transit time of the beam across the gap between the grid and the target.
  • Fixed Faraday cup that cannot be removed from the beam path and therefore is limited to usage at the end of the beamline.
Faraday Cup model 28

The above beam power ratings are for a continuous beam with a diameter of 3mm or greater and with appropriate cooling.


Required Faraday Cup Accessories

A complete Faraday cup system includes a Faraday cup, a controller for actuation, and either a picoammeter or logarithmic amplifier for current reading.

Faraday Cup Controllers:

NEC offers a local and remote controller.



Current Readers:



More Information

Faraday Cup Specifications
Multi-Unit Faraday Cup Controllers