Description
Measure photosynthetically active radiation, PAR, in µmol m-2 s-1.
Apogee Instruments’ quantum sensors provide accurate and cost-effective measurement of photosynthetically active radiation (PAR) from all light sources used to grow plants and corals.
Spectral Response
The full-spectrum quantum sensor has a spectral range of 389 to 692 nm ± 5 nm. The improved spectral response increases the accuracy of LED measurements. The spectral responses can be seen in the graph below.
Graph showing the spectral responses of full-spectrum quantum sensor (spectral range of 389 to 692 nm ± 5 nm).
Accurate, Stable Measurements
Sensors are cosine-corrected to maintain their accuracy when radiation comes from low zenith angles. The sensors measure PPFD with a cosine response accurate within ± 5 % at 75° zenith angle. Long-term non-stability determined from multiple replicate quantum sensors in accelerated aging test and field conditions is less than 2 % per year.
Typical Applications
PPFD measurements 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 PPFD in aquatic environments, including salt water aquariums where corals are grown.
Rugged, Self-cleaning Housing
Patented domed shaped sensor head (diffuser and body) facilitate runoff of dew and rain to keep the sensor clean and minimize errors caused by dust blocking the radiation path. Sensors are housed in a rugged anodized aluminum body and electronics are fully potted.
Ideal for Measurements in Air and Underwater
Apogee quantum sensor are calibrated to make absolute PPFD measurements in air. The waterproof sensors can be used to make absolute PPFD measurements underwater by applying an immersion effect correction factor, the SQ-420, SQ-520, MQ-210, and MQ-510 already apply the correction factor. For details on making underwater measurements, please refer to Underwater PAR Measurements.
Calibration
To ensure accuracy each sensor is carefully calibrated in controlled conditions and traceable to NIST reference standards. The full-spectrum sensors are pre-calibrated for all light sources.
Mounting
The AL-120 Solar Mounting Bracket with Leveling Plate facilitates mounting the sensor to a mast or pipe. The AL-100 Solar Sensor Leveling Plate is designed to level the sensor while sitting on a flat surface or mounting to a surface.
Output Options
Available in multiple analog output options including 0 to 40 mV, 0 to 2.5 V, and 0 to 5 V. Additionally, a digital “smart” sensor that uses USB communication and custom software to interface directly to a computer is available. Sensors are also available attached to a hand-held meter with digital readout.
High Quality Cable
Pigtail-lead sensors feature an IP68, marine-grade stainless-steel cable connector approximately 30 cm from the head to simplify sensor removal for maintenance and recalibration. Cable is shielded-twisted pair wire with a TPR jacket for high water resistance, UV stability, and flexibility in cold conditions.
Warranty and Support
All Apogee products are backed by an industry-leading four year warranty and outstanding customer support.
SQ-500-SS-L-10 | SQ-512-SS(0-2.5V) | SQ-514-SS(4-20mA) | SQ-515-SS(0-5.0V) | SQ-520(USB) | SQ-521-SS(SDI-12) | |
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Power Supply | Self-powered | 3.3 to 24 V DC | 12 to 24 V DC | 5.5 to 24 V DC | 5 V USB power source | 5.5 to 24 V DC |
Current Draw | – | At 12 V is 57 µA | maximum of 20 mA | At 12 V is 57 µA | 61 mA when logging | 1.4 mA (quiescent); 1.8 mA (active) |
Output (Sensitivity) | 0.01 mV per µmol m-2 s-1 | 0.625 mV per µmol m-2 s-1 | 0.004 mV per µmol m-2 s-1 | 1.25 mV per µmol m-2 s-1 | – | – |
Output Type | 0 to 40 mV | 0 to 2.5 V | 4 to 20 mA | 0 to 5 V | USB | SDI-12 |
Resolution | – | – | – | – | 0.1 µmol m-2 s-1 | – |
Calibration Factor (reciprocal of sensitivity) | 100 µmol m-2 s-1 per mV | 1.6 µmol m-2 s-1 per mV | 250 µmol m-2 s-1 per mA | 0.8 µmol m-2 s-1 per mV | Custom for each sensor and stored in the firmware | Custom for each sensor and stored in the firmware |
Calibration Uncertainty | ± 5 % | ± 5 % | ± 5 % | ± 5 % | ± 5 % | ± 5 % |
Measurement Repeatability | Less than 0.5 % | Less than 1 % | Less than 0.5 % | Less than 1 % | Less than 0.5 % | Less than 1 % |
Long-term Drift per Year | Less than 2 % per year | Less than 2 % per year | Less than 2 % per year | Less than 2 % per year | Less than 2 % per year | Less than 2 % per year |
Non-linearity | Less than 1 % (up to 4000 µmol m-2 s-1) | Less than 1 % (up to 4000 µmol m-2 s-1) | Less than 1 % (up to 4000 µmol m-2 s-1) | Less than 1 % (up to 4000 µmol m-2 s-1) | Less than 1 % (up to 4000 µmol m-2 s-1) | Less than 1 % (up to 4000 µmol m-2 s-1) |
Response Time | Less than 1 ms | Less than 1 ms | Less than 1 ms | Less than 1 ms | Software updates every second | Less than 0.6 s |
Field of View | 180° | 180° | 180° | 180° | 180° | 180° |
Spectral Range | 389 to 692 nm ± 5 nm (wavelengths where response is greater than 50 %) | 389 to 692 nm ± 5 nm (wavelengths where response is greater than 50 %) | 389 to 692 nm ± 5 nm (wavelengths where response is greater than 50 %) | 389 to 692 nm ± 5 nm (wavelengths where response is greater than 50 %) | 389 to 692 nm ± 5 nm (wavelengths where response is greater than 50 %) | 389 to 692 nm ± 5 nm (wavelengths where response is greater than 50 %) |
Spectral Selectivity | Less than 10 % from 412 to 682 nm ± 5 nm | Less than 10 % from 412 to 682 nm ± 5 nm | Less than 10 % from 412 to 682 nm ± 5 nm | Less than 10 % from 412 to 682 nm ± 5 nm | Less than 10 % from 412 to 682 nm ± 5 nm | Less than 10 % from 412 to 682 nm ± 5 nm |
Directional (Cosine) Response | ± 5 % at 75° zenith angle | ± 2 % at 45°; ± 5 % at 75° | ± 2 % at 45°; ± 5 % at 75° | ± 2 % at 45°; ± 5 % at 75° | ± 5 % at 75° zenith angle | ± 2 % at 45°; ± 5 % at 75° |
Temperature Response | -0.11 ± 0.04 % per C | -0.11 ± 0.04 % per C | -0.11 ± 0.04 % per C | -0.11 ± 0.04 % per C | -0.11 ± 0.04 % per C | -0.11 ± 0.04 % per C |
Operating Environment | -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m | -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m | -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m | -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m | -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m | -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m |
Dimensions | 24 mm diameter, 37 mm height | 30.5 mm diameter, 37 mm height | 30.5 mm diameter, 37 mm height | 30.5 mm diameter, 37 mm height | 24 mm diameter, 37 mm height | 30.5 mm diameter, 37 mm height |
Mass (5 m of cable) | 100 g | 140 g | 140 g | 140 g | 100 g | 140 g |