Apogee line quantum sensors measure a spatial average of PAR (Photosynthetically Active Radiation). The SQ-311 has a sensor bar with 10 sensors and is self-powered with a 0 to 800 mV output. The sensor is calibrated for use in sunlight (Custom electric light calibration is available. Contact Apogee for details). The sensor housing design features an integrated bubble level and is fully potted making the sensor weatherproof. Typical applications include PPFD (Photosynthetic Photon Flux Density) measurement over plant canopies in outdoor environments, greenhouses, and growth chambers, and reflected or under-canopy (transmitted) PPFD measurements in the same environments. Quantum sensors are also used to measure PAR/PPFD in aquatic environments, including salt water aquariums where corals are grown. Sensor includes IP67 marine-grade stainless-steel cable connector 30 cm from head to simplify sensor removal and replacement for maintenance and recalibration.
Power Supply Self-powered
Sensitivity 0.2 mV per µmol mˉ² sˉ¹
Calibration Factor 5 µmol mˉ² sˉ¹ per mV (reciprocal of sensitivity)
Calibration Uncertainty ± 5 %
Calibrated Output Range 0 to 800 mV
Measurement Repeatability Less than 0.5 %
Non-stability (Long-term Drift) Less than 2 % per year
Non-linearity Less than 1 % (up to 4000 µmol mˉ² sˉ¹)
Response Time Less than 1 ms
Field of View 180˚
Spectral Range 410 nm to 655 nm
Spectral Selectivity Less than 10 % from 469 to 653 nm
Directional (Cosine) Response ± 5 % at 75˚ zenith angle
Temperature Response 0.06 ± 0.06 % per C
Operating Environment -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m
Dimensions 700 mm length, 15 mm width, 15 mm height
Mass 375 g (with 5 m of lead wire)
Cable 5 m of shielded, twisted-pair wire with TPR jacket (high water resistance, high UV stability, flexibility in cold conditions)
Warranty 4 years against defects in materials and workmanship
