Model 439 Digital Current Integrator

• Measures DC current and average pulse current with high accuracy
• Functions as digital current integrator, charge integrator, or digital electrometer
• Converts input charge into digital output pulses for precise counting
• Selectable charge sensitivity: 10⁻¹⁰, 10⁻⁸, or 10⁻⁶ Coulomb per pulse
• Wide dynamic range with digitizing rate up to 10 kHz
• High accuracy and reproducibility for low-current measurements
• Built-in analog output + digital pulse output for flexible system integration
• Input protection up to ±1000 V / ±2000 V (capacitive protection)
• Compatible with counters, timers, and MCA systems for full measurement solutions

The Model 439 Digital Current Integrator is a high-precision electronic instrument designed to measure direct current (DC) and average pulse currents, such as those generated in particle accelerators, beam diagnostics, and radiation experiments.

Unlike traditional analog measurement systems, the Model 439 digitizes the input signal by converting accumulated charge into discrete output pulses, where each pulse represents a defined quantity of charge. This enables highly accurate and noise-resistant current measurement, even at very low signal levels.

Users can select between three charge-per-pulse settings (10⁻¹⁰, 10⁻⁸, 10⁻⁶ Coulomb), allowing flexible scaling for different experimental conditions and count rates.

When integrated with other electronics:

Combined with a preset counter → functions as a digital charge integrator
Combined with a counter + timer → functions as a digital electrometer

The system also features a front-panel analog meter and multiple analog outputs, enabling real-time monitoring alongside digital acquisition.

With its high accuracy, wide dynamic range, and flexible integration, the Model 439 is ideal for beam current measurement, low-level current detection, and precision charge integration applications.

Product Type: Digital Current Integrator (NIM module)
Measurement Type:

• DC current
• Average pulse current

Current Range: ~1 × 10⁻⁹ to 1 × 10⁻² A
Charge per Pulse (Selectable): 10⁻¹⁰, 10⁻⁸, 10⁻⁶ Coulomb
Digitizing Rate: 0 to 10 kHz
Accuracy: ≤ ±0.2% (100 nA to 10 mA range)
Reproducibility: ~0.01%
Input Characteristics:

• Impedance: >10¹⁰ Ω
• Leakage current: <10⁻¹² A

Outputs:
Digital: +5 V pulses (0–10 kHz)
Analog:

• 1 mA
• 100 mV
• 10 mV full-scale outputs

Control Features:

• Polarity selection (positive/negative current)
• Gate input for output inhibition/control
• Offset current adjustment (~±10 pA)

Power Requirement: NIM bin power supply
Form Factor: NIM-standard triple-width module

• Accelerator beam current measurement
• Charge integration in nuclear experiments
• Low-current measurement in physics research
• Radiation detector current monitoring
• Ion beam and particle beam diagnostics
• Precision electrometer applications
• Laboratory and research instrumentation