COVID-19 Update: We remain open and ready to help. Read More

Thank you for your inquiry.

Despite the recent COVID-19 outbreak, we remain dedicated to providing support to customers like you. In compliance with current health recommendations, our team has temporarily reduced its hours of operation to help keep us safe and operational. Our response time may be delayed as we continue to assess and adapt to these events.

While we review your inquiry, please visit our support site for additional resources.

Take care,

—The LI-COR Team

Thank you for your request.

You will receive an email shortly.

If you do not receive it within 24 hours or if you have any questions, please cont'ac't LI-COR at 1-402-467-3576.

Thank you for your inquiry.

Despite the recent COVID-19 outbreak, we remain dedicated to providing support to customers like you. In compliance with current health recommendations, our team has temporarily reduced its hours of operation to help keep us safe and operational. Our response time may be delayed as we continue to assess and adapt to these events.

While we review your inquiry, please visit our support site for additional resources.

Take care,

—The LI-COR Team

Thank you for your interest in the LI-180 Spectrometer.

Unfortunately, the LI-180 is only currently available in select countries. We will notify you when the LI-180 is available for purchase in your country.

Request a Quote for the

Complete the form to get your quote from a LI-COR representative.


Request a Quote for the

Complete the form to get your quote from a LI-COR representative.


Request a Quote for the LI-180 Spectrometer

LI-191R
Line Quantum Sensor

LI-191R Quantum Line Sensor

The LI-191R Line Quantum Sensor measures PAR integrated over its 1-meter length. It is used to measure sunlight under a plant canopy, where the light field is non-uniform. The LI-191R makes it easy to measure under-canopy light in many plots quickly and consistently. It measures light in units of Photosynthetic Photon Flux Density (PPFD), which is expressed as μmol s-1 m-2.

Request a Quote Download Brochure


Why choose the LI-191R?

  • Improved water resistance for long-term outdoor deployment
  • Integrated measurements using a single detector prevents variance found in sensors that use multiple detectors
  • Selected by the National Ecological Observatory Network (NEON®) for integrated PAR measurements

How does it work?

The LI-191R uses a 1-meter long quartz rod under a diffuser to direct light to a single filtered silicon photodiode. The entire LI-191R diffuser is sensitive to light over its 1-meter length. Since the diffuser is one continuous piece, the LI-191R essentially integrates an infinite number of points over its surface into a single value that represents light from the entire 1-meter length. Optical filters block radiation with wavelengths beyond 700 nm, which is critical for under-canopy measurements, where the ratio of infrared to visible light may be high. The unique design of the LI-191R provides an excellent quantum response that is close to the ideal quantum response.

LI-191R Specifications

  • Absolute Calibration: ± 10% traceable to National Institute of Science and Technology (NIST). The LI-191 is calibrated via transfer calibration using a reference LI-190R Quantum Sensor. Transfer error is ± 5% (included in the ± 10%)
  • Sensitivity: Typically 7 μA per 1,000 μmol s-1 m-2
  • Linearity: Maximum deviation of 1% up to 10,000 μmol s-1 m-2
  • Response Time: 10 μs
  • Temperature Dependence: ± 0.15% per °C maximum
  • Cosine Correction: Acrylic diffuser
  • Azimuth: < ± 2% error over 360° at 45° elevation
  • Operating Temperature Range: −40 °C to 65 °C
  • Relative Humidity Range: 0% to 95% RH, Non-Condensing
  • Sensitivity Variation over Length: ± 7% maximum using a 2.54 cm (1”) wide beam from an incandescent light source.
  • Sensing Area: 1 m × 12.7 mm (39.4” × 0.50”)
  • Detector: High stability silicon photovoltaic detector (blue enhanced)
  • Sensor Housing: Weatherproof anodized aluminum housing with acrylic diffuser and stainless steel hardware.
  • Size: 121.3 L × 2.54 W × 2.54 cm D (47.7” × 1.0” × 1.0”)
  • Weight: 1.4 kg (3.0 lbs.)
  • Cable Length: 3.1 m (10.0 ft.)

Need a data logger or light meter?

Check out the LI-1500 Light Sensor Logger and LI-250A Light Meter.

2291 Light Sensor Millivolt Adapter

Have a data logger already?

You might want a signal conditioner, such as a Millivolt Adapter or Light Sensor Amplifier.


Quantum Sensor Resources