I404 Quad Current Integrator
The I404 is a high-performance four-channel charge integrator designed for precision applications including quadrant photodiode readout, beam position monitoring, and ultra-low current measurement. It offers an enhanced dynamic range from <1 pA to 200 µA, integrated digitisation with advanced filtering, and flexible interfacing via fibre-optic, RS-232, and RS-485 connections. With selectable integration modes, external trigger capability, and optional high-voltage output, the I404 delivers versatile functionality and, with its built-in calibration source and configurable analogue and frequency monitor outputs, it is ideal for demanding diagnostic environments.
Features
- Four gated integrator channels
- Dynamic range <1 pA to 200 µA
- Integrated digitisation and filtering
- Fibre-optic, RS-232 and RS-485 interfaces
- Integrated calibration test source
- Selection of current and charge integration modes
- External trigger capability
- Four independent analogue/frequency monitor outputs, configurable to show various analog parameters such as current, position
- Optional high voltage output
Applications
- Quadrant photodiode readout
- Low current and charge measurement
- Beam position monitors
Options
- Auxiliary HV output
- Alternative feedback capacitor options
Specifications
| Parameter | Value |
|---|---|
| Operating principle | Gated integrator (charge integrating amplifier) |
| Integration capacitor | Dual, software selectable in real time |
| Dynamic Range | <1 pA to 200 µA |
| Input noise | < 100 fA rms + 1 fA rms per pF input load up to 100 pF (1 s integration, 100 pF capacitor) |
| Input offset | < 100 pA, 15 to 25 °C. Offset can be removed by zero subtraction |
| Stability | Output drift < 200 fA / °C / hour |
| External accuracy | Better than 0.5% of full scale in use, integration time 500 μs to 1 s, after calibration with built-in current source |
| Integration time | User selectable, 100 μs to 65 s |
| Integration modes | Continuous charge/current, charge accumulation, triggered burst |
| External gate | TTL 10 kΩ impedance |
| Trigger modes | Internal (autorun), external start, external start/stop, sternal start/hold, message |
| Digitisation | 16 bit bipolar, 50 kHz effective per channel Built-in digital averaging gives 20 bit effective resolution for 32 integrations |
| Auxiliary HV PSU | (Factory option) 0 to 2000 V programmable (polarity and maximum voltage factory selectable), 1 W max. Noise and ripple < 0.1% |
| Power input | +24 V (± 2 V) DC, 350 mA typ, 500 mA max |
| Controls | Two rotary switches for loop address and comms mode/baud rate |
| Displays | Status LEDs (power, device status, comms mode, data RX/TX) “HV on” LED |
| Case material | Stainless steel sheet |
| Weight | 1.64 kg (3.6 lb) |
| Operating environment | 10 to 35 °C (15 to 25 °C recommended to reduce drift and offset), < 70% humidity, non-condensing, vibration < 0.1 g all axes (1 to 1000 Hz) Vibration must be as low as possible to measure at the lower limit of the dynamic range |
| Shipping and storage environment | -10 to 50 °C, < 80% humidity, non-condensing, vibration < 2 g all axes, 1 to 1000 Hz |
