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LI-193 Spherical Underwater Quantum Sensor

Updated:2025-03-13

Brand: LI-COR
Model: LI-193
Description: The LI-193 Spherical Quantum Sensor measures PAR in air or underwater from all directions at depths up to 350 meters. This sensor is useful for studies of phytoplankton, which uses radiation from all
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Product Details

LI-193 Spherical Underwater Quantum Sensor Description：

Product Manual

The LI-193 Spherical Quantum Sensor measures PAR in air or underwater from all directions at depths up to 350 meters. This sensor is useful for studies of phytoplankton, which uses radiation from all directions. The measurement is referred to as Photosynthetic Photon Flux Fluence Rate (PPFFR) or Quantum Scalar Irradiance.

Character

Designed for immersion

Measures PAR from all directions

Ideal for oceanography, limnology, turbidity, and vertical profiling

Working Principle

The LI-193 uses a diffusive sphere to direct light through glass optical filters to the silicon photodiode. The filters create uniform sensitivity to light between 400 and 700 nm, which closely corresponds to light used by most terrestrial and aquatic plants and algae. The angular response of a typical LI-193 is slightly lower in the direction of the cable connection. When mounted, the low response is usually not significant due to the small proportion of upwelling radiation compared to the total.

Cables and Accessories

LI-193 cables are available in lengths from 3 meters to 100 meters.

We recommend the 2009S Lowering Frame to lower the sensor into water.

LI-193 Spherical Underwater Quantum Sensor Specifications：

Absolute Calibration	± 5% in air traceable to NIST
Sensitivity	Typically 4 μA per 1,000 μmol s^-1 m^-2 in water
Linearity	Maximum deviation of 1% up to 10,000 μmol s^-1 m^-2
Response Time	10μs
Temperature Dependence	± 0.15% per °C maximum
Cosine Correction	Optimized for underwater and atmospheric use
Azimuth	< ± 1% error over 360° at 45° elevation
Operating Temperature Range	?40 °C to 65 °C
Detector	High stability silicon photovoltaic detector (blue enhanced)
Sensor Housing	Corrosion resistant metal with acrylic diffuser for both saltwater and freshwater applications. Waterproof to withstand approximately 5500 kPa, 560 meters (800 psi).
Size	3.18 cm diameter × 4.62 cm height (1.25” × 1.81”)
Weight	227 g (8 oz)
Mounting	Three 6-32 holes are tapped into the base for use with the 2009S Lowering Frame or other mounting devices
Cable	Requires 2222UWB Underwater Cable (available in 3, 10, 30, 50, 100 meter lengths)