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Part Numbers
LI-190R-SMV-2
•LI-190R-SMV-5
•LI-190R-SMV-15
•LI-190R-SMV-50
LI-COR LI-190R SMV Quantum Sensor
Photosynthetically active radiation (PAR) measurement precision—no matter the source
From $530.00 USD
This industry-leading PAR sensor from LI-COR Environmental provides highly precise measurements of most broad-spectrum light sources, including natural sunlight, artificial, and mixed.
Overview
The LI-190R-SMV measures Photosynthetically Active Radiation (PAR), in µmol of photons m-2 s-1. It provides accurate measurements—in the open, in greenhouses, under plant canopies, or in growth chambers—for most broad-spectrum light sources, including natural sunlight, artificial, or mixed sources.
Plants use light in the wavelength range from about 400 to 700 nm to drive photosynthesis. The efficiency with which plants use light varies somewhat across this range, but McCree1 showed that measuring PAR provided a consistent way to predict plant photosynthetic response regardless of the spectrum of the light source.2
Why monitor PAR with a LI-190R Light Sensor?
- Uniform sensitivity across the PAR waveband for accurate measurements outdoors, under vegetation, or in artificial lighting without changing the calibration
- Newly designed optical filter tailors the spectral response to an unprecedented performance standard
- Weather-resistant and durable in high-temperature, high-humidity, long-term deployments
- Cosine correction is accurate even when the light source is not directly overhead
- Sensor heads are detachable and interchangeable for simplified installation, removal, and recalibration
1McCree, K.J., 1972. The action spectrum, absorptance and quantum yield of photosynthesis in crop plants. Agric. Meteorol. 9: 191-216.
2McCree, K.J., 1972. Test of current definitions of photosynthetically active radiation against leaf photosynthesis data. Agric. Meteorol. 10: 443-45
Features
How does it work?
The LI‑190R uses a high-quality silicon photodiode and glass optical filter to create uniform sensitivity to light between 400 nm to 700 nm, which closely corresponds to light used by most plants. A newly designed optical filter tailors the spectral response to an unprecedented performance standard. Furthermore, the new filter is unaffected by environmental factors such as heat or humidity. The filter blocks light with wavelengths beyond 700 nm, which is critical for measurements under vegetation where the ratio of infrared to visible light may be high.
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The LI-190R sensor features excellent cosine response, which ensures accurate measurements under diffuse light and when sunlight originates from a low solar angle. This, in combination with high resolution at low light levels, makes the LI-190R useful for determining the light compensation point in plants.
Specifications
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± 5% traceable to the U.S. National Institute of Standards and Technology (NIST)
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Typically 5 μA to 10 μA per 1,000 μmol s-1 m-2
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Maximum deviation of 1% up to 10,000 μmol s-1 m-2
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Less than 1μs (2 m cable terminated into a 604 Ohm load)
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± 0.15% per °C maximum
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Cosine corrected up to 82° angle of incidence
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< ± 1% error over 360° at a 45° elevation
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No error induced from orientation
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−40 °C to 65 °C
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0% to 100% RH, Non-Condensing
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High stability silicon photovoltaic detector (blue enhanced)
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Weatherproof anodized aluminum body with acrylic diffuser and stainless steel hardware; O-ring seal on the sensor base
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2.36 cm diameter × 3.63 cm0.93” diameter × 1.43”
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24 g head; 60 g base/cable (2 m) with screws
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2 m, 5 m, 15 m, 50 m6.5’, 16.4’, 49.2’, 164’
Absolute Calibration
Sensitivity
Linearity
Response Time
Temperature Dependence
Cosine Correction
Azimuth
Tilt
Operating Temperature Range
Relative Humidity Range
Detector
Sensor Housing
Size
Weight
Cable Length