Gamma Scientific / UDT Instruments 301-DIV Position Monitor

The Gamma Scientific / UDT Instruments 301-DIV Position Monitor is a signal conditioning amplifier that interfaces position-sensing photodetectors with user-supplied indicators and controls. Using transimpedance and differential amplifiers, it generates analog outputs proportional to detector position while actively canceling variations in incident light intensity. The device divides differential output by summed output to deliver normalized position data across single or dual axes.

Technical Specifications

Input Current Range: Six selectable ranges from 3 µA to 2 mA

Output Voltage Range: 0 to 10 V (user adjustable)

Frequency Bandwidth: DC to 5 kHz (standard); DC to 30 kHz (high-speed version)

Output Impedance: 100 ohm (30 kHz version)

Noise (rms): 2 mV at 10 V full scale

Detector Bias: Selectable 0 VDC (photovoltaic) or 15 VDC (photoconductive)

Power Requirements: 210 to 250 VAC, 50/60 Hz, 5 watts (301DIV-230V model)

Sum Output: GAIN × (ID + IE)

Key Features

Six selectable input ranges with LED indicators for range verification

Transimpedance signal conditioning optimized for low-level photodetector currents

Ratiometric output design eliminates intensity-related measurement drift

Adjustable scale factor for position calibration

Selectable detector polarity: common anode or common cathode

Single-axis configuration per module

Typical Applications

Precision position measurement and nulling operations

Beam centering and tracking in optical systems

Continuous position monitoring across detector active area

Applications requiring normalized position output independent of incident intensity variations

Compatibility & Integration The 301-DIV accommodates bi-cells, quadrant detectors, and lateral-effect detectors. Duo-lateral detectors are incompatible. Single modules measure one axis; dual-axis applications require two 301-DIV units. Quadrant and tetralateral detector systems also require two modules. Sum and position outputs interface with external data acquisition or control electronics.