The MQ-500 is Apogee Instruments' new quantum meter with an improved spectral response, providing accurate PAR/PPFD measurements under all light sources, including LEDs.
|Measurement Repeatability||less than 1%|
|Long-term Drift||less than 2% per year|
|Non-linearity||less than 1% (up to 2500 µmol m-2s-1|
|Response Time||less than 1ms|
|Field of View||180°|
|Spectral Range||389 to 692nm (wavelengths where response is greater than 50% of maximum)|
|Directional (Cosine) Response||±5% at 75° zenith angle|
|Temperature Response||-0.11 ± 0.03% per °C|
|Operating Environment||0 to 50°C; less than 90% non-condensing relative humidity up to 30°C;
less than 70% non-condensing relative humidity from 30 to 50°C;
separate sensors can be submerged in water up to depths of 30m
|Meter Dimensions||126mm length, 70mm width, 14mm height|
|Sensor Dimensions||24mm diameter; 35mm height|
|Mass||100g (with 5m of lead wire)|
|Cable||2m of shielded, twisted-pair wire; additional cable available; santoprene rubber jacket|
|Warranty||4 years against defects in materials and workmanship|
Mean cosine response of seven Apogee SQ-500 quantum sensors. Cosine response measurements were made on the rooftop of the Apogee building in Logan, UT.
Cosine response was calculated as the relative difference of SQ-500 quantum sensors form the mean of replicate reference quantum sensors (LI-COR models LI-190 and LI-190R, Kipp and Zonen model PQS 1). The red data are AM measurements; the green data are PM measurements.
Mean spectral response measurements of six replicate SQ-100 and SQ-500 series quantum sensors. Spectral response measurements were made at 10nm increments across a wavelength range of 300 to 800mm in a monochromator with an attached electric light source. Measured spectral data from each quantum sensor were normalized by the measured spectral response of the monochromator/electric light combination, which was measured with a spectroradiometer
|Kipp & Zonen
|Sun (Clear Sky)||-2.2||0.0||-0.4||-1.0|
|Sun (Cloudy Sky)||-1.7||1.4||-0.2||-1.3|
|Sun (Reflected from Deciduous Leaves)||-2.0||4.9||-0.8||1.1|
|Sun (Transmitted below Wheat Canopy)||-1.1||6.4||-0.1||-0.3|
|Cool White Fluorescent (TS)||0.0||0.0||0.0||0.0|
|Ceramic Metal Halide||-0.3||-6.0||0.4||-0.7|
|High Pressure Sodium||0.0||0.8||1.3||1.4|
|Red/Blue LED (16% 444nm, 84% 667nm peaks)||-3.4||– 65.3||3.5||-1.8|
|Red/White LED (6.5% 436nm, 4.5% 531 nm, 89% 668nm peaks)||-3.0||-60.3||2.6||-1.7|
Spectral errors are theoretical errors calculated from sensor spectral responses (Apogee SQ-100 and SQ-500 series shown in graph above) and spectral output of radiation sources (measured with a spectroradiometer). Only spectral errors are listed in the table. Calibration, cosine, and temperature error can also contribute to measurement error.
Apogee Instruments SQ-500 series quantum sensors are calibrated through side-by-side comparison the the mean of four Apogee model SQ-500 transfer standard quantum sensors under high output T5 cool white fluorescent lamps. The transfer standard quantum sensors are calibrated through side-by-side comparison the the mean of at least three LI-COR model LI-190 reference quantum sensors under high output T5 cool white fluorescent lamps. The reference quantum sensors are recalibrated on a biannual schedule with a LI-COR model 1800-02 and quartz halogen lamp, traceable to the National Institute of Standards and Technology (NIST).