I400 - 4 Channel Biased Input Charge Integrating Electrometer

The I400 is intended for the measurement of small charges or corresponding currents (from pA to µA) generated by devices such as ionization chambers, in-vacuum beam position monitors, proportional chambers, and photodiodes. Four input channels make the I400 particularly well-suited to four-quadrant electrode systems used for beam centering. The unit may be stand-alone or networked with other devices and integrated into a larger system.

See the I404 for an electrometer with unbiased inputs suitable for detectors at ground potential.


  • Four parallel gated integrator channels
  • Programmable bias voltage from 0V to +/-400V
  • Dynamic range < 0.1pA to >70µA
  • Low noise, < 100fA RMS +1fA RMS per pF input load
  • Stable output drift < 5ppm/C/Hour
  • Integrated digitization and communications
  • Integrated calibration test source
  • Multimode external triggering capability
  • Diagnostic host software with position algorithms and multiple display options


  • Ionization chamber readout
  • Secondary-electron beam position monitors
  • White beam blade BPMs
  • Photodiodes and photodiode beam position monitors
  • Diamond detector readout
  • General very-low current and charge measurement

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