The QSRED quantum sensor consists of a handheld display unit and matched cosine corrected, large surface area sensor head containing a special high grade photocell filtered for light falling into the 550 - 750nm waveband. The quantum sensor head is fully sealed and therefore weatherproof allowing it to be positioned indefinitely in exposed positions. The QSRED quantum sensor has been calibrated under open-sky conditions against reference pyranometers and hence referred to the World Radiometric Reference. The linearity of response is excellent with a maximum deviation of 1% up to levels of 3000 watts/m² (greater than normal solar irradiance).

The display unit is matched to the sensor head supplied ensuring correct calibration. The µmol m^-2 s^-1 calibrated value from the quantum sensor is displayed on the LCD display. 3 measurement ranges allow maximum sensitivity from 0 - 2000 µmol m^-2 s^-1. A 0 - 2v analogue output allows measured PAR values to be plotted on a suitable recording device. QSRED is intended to be used primarily as a calibration tool for Hansatech Instruments red LED light sources. The instrument is powered by a single PP3 battery.