I400 4-channel Digital Electrometer

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This four channel current and charge amplifier with biased inputs provides high performance, multiple operating modes and a wide range of communication options in a compact unit. Four gated integrator channels can operate in current or charge monitoring modes, over a wide range of signal amplitudes. A dedicated gate control input allows the integration to be coordinated with external events.
Data output is via RS232, USB and fast serial fibre optic. An optional fibre loop controller module connects multiple devices to a single Ethernet port.

  • Four gated integrator channels with adjustable bias voltage
  • Dynamic range 0.1 pA to 100 μA
  • Integrated digitisation and communications
  • Integrated calibration test source
  • Selection of current and charge integration modes
  • External synchronization capability


  • Ionization chambers
  • Beam position monitors
  • Photodiodes
  • Ultra-low current and charge measurement


  • Auxiliary HV output 0 to 1000 V
  • Pressure and temperature inputs
  • Alternative feedback capacitor options


Parameter Value
Integration capacitor Dual, selectable
Input noise < 10 fA rms + 1 fA rms per pF input load up to 100 pF
(1 second integration, 10 pF capacitor, 0 V bias)
Input offset current < 100 fA at 0V bias, 25 C
< 600 fA at 0V bias, 50 C
< 200 fA at 400V bias, 25 C
Stability Output drift < 5 ppm / C / hour
Integration time User selectable, 100 μsec minimum.
Integration modes 0: continuous current;
1: continuous charge,
2: lossless charge;
3: external gate integration;
4: externally-triggered burst mode
External gate 0/+5 V, 50 ohm
Digitisation Four independent ADCs, 16 bit bipolar, 200kHz
Bias HV PSU 0 to 400 V programmable, (polarity factory selectable),
1mA max. Noise and ripple < 0.1%
Auxiliary HV PSU (Factory option) 0 to 1000 V programmable (polarity factory selectable),
1 mA max. Noise and ripple < 0.1%
Power input +24 V (+/- 2 V) DC, 350 mA typ, 500 mA max.
Case material Al alloy 6060 (Al Mg Si) black powder coat, SBS elastomer end flange seals
Weight 1.64kg (3.6 lb) including mounting plate
Operating environment 10 to 35C (15 to 25 C recommended to reduce drift and offset),
< 70% humidity, non-condensing, vibration < 0.1g all axes (1 to 1000Hz)
Shipping and storage environment -10 to 50 C, < 80% humidity, non-condensing, vibration < 2g all axes, 1 to 1000 Hz