4-channel Charge Integration Picoammeter

4-channel simultaneous sampling electrometer with 8 input current ranges (20 bit), 10/100 Mbit Ethernet connectivity and Trigger Input

  • Overview
  • Features
  • Technical specifications
  • Ordering options
  • Documentation
  • Software/Firmware


Charge integration allows not losing any information on the charge received in a user-defined integration time.

The AH401D is a compact 4-channel low noise picoammeter. It is composed of an extremely sensitive charge-integration input stage for low-current sensing, combined with a 20-bit delta-sigma AD converter with an integrated noise reduction digital filter.

This device is suited for very low current measurements, with 8 selectable input ranges spanning from 50 pA (with a 50-aA resolution) up to 2 µA (with a 2-pA resolution). Integration time is user selectable and ranges from 1 ms up to 1 s. Each input channel has two integrator stages so that the current-to-voltage conversion can be performed continuously during ADC conversion, avoiding any dead time in the data output. The simultaneous sampling of the 4 independent channels make this instrument ideal for beam position monitor applications or multichannel acquisition.

The new AH401D is housed in a light and extremely compact box that can be placed close to the signal sources in order to reduce cable lengths and minimize possible noise pick-up. Low temperature drift, good linearity and very low noise allow very high precision current measurements.

Ethernet connectivity and easy configuration make the AH401D the perfect fit in many low-current multi-channel applications.

The picoammeter can be remotely controlled via a standard Ethernet 10/100 Mbit TCP-IP or UDP communication interface: integration time, range, data format, type of acquisition and many other parameters can be easily set and monitored.

The AH401D has an external TRIGGER input signal in order to synchronize the acquisition of the picoammeter with external events (e.g. laser triggering). Furthermore, digital samples can be transferred either using ASCII format or RAW binary data format for fast data transmission.

The Plug-and-Play solution for your Beam Position Monitor applications with dedicated Oscilloscope software.

Perform your current measurements, photon beam position and intensity computations and noise analysis with only one device!

Different detector geometries as well spectra analysis and data savings can be directly set, configured and analyzed on the GUI.


  • 4-channel simultaneous sampling
  • Up to 1 ksps data rate
  • From 50 pA to 2 μA current range
  • 20 bit A/D converter with noise reduction digital filter
  • Less than 7 ppm@200 pC full-scale range noise
  • Lightweight and compact design
  • Linear low-noise power supply PS2209 included
  • Ethernet 10/100 Mbit communication interface
  • External Trigger

Technical specifications




Input Channels


Current Measuring Full-Scale Range

from 50 pA to 2.0 µA

Current Polarity

Positive only
(-0.4 % of Full-Scale allowed)

Data Rate

up to 1 ksamples/s

Integration Time

from 1 ms to 1 s



Noise (@1ms, 200pCFS)

< 7 ppm/FS

Communication Interface

Ethernet 10/100 Mbit TCP-IP and UDP

I/O Signals

CONV output

Supply Voltage

9 V


155 × 165 × 42 mm


560 g

Input Connectors


LED indicators


Ordering options

Ordering code




AH401D – 4-channel Multi-range Charge-Integration Picoammeter with +/-9 V Linear Power Supply


Last reviewed: 2022-12-09 ⓘ More infoRevision: 1.6

Last reviewed: 2022-12-09 ⓘ More infoRevision: 1.1

Last reviewed: 2023-02-03 ⓘ More infoRevision: 2.0


Updated: 2023-01-24 - 110.79 MB ⓘ More info Version: 1.2
OS: Windows

Copyright CAEN ELS s.r.l.