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Spherical Quantum Sensor
The LI-193 Underwater Spherical Quantum Sensor gives an added dimension to underwater PAR measurements as it measures photon flux from all directions. This measurement is referred to as Photosynthetic Photon Flux Fluence Rate (PPFFR) or Quantum Scalar Irradiance. This is important, for example, when studying phytoplankton, which utilise radiation from all directions for photosynthesis.
LI-193 Spherical Quantum Sensor provides underwater PAR from all directions
The LI-193 features a high sensitivity optical design and compact, rugged construction (3400 kPa, 350 metres depth, 3400 kPa = 493 psi).
The graph at right indicates the typical angular response of the LI-193 Spherical Quantum Sensor. The low response on the bottom of the sensor is due to light blockage by the detector housing. The error due to this low response is not significant in most cases because of the small portion of upwelling radiation compared to the total radiation.
Underwater Sensors can be purchased with several accessories. The LI-193SA must be used in combination with a 2222UWB Underwater Cable. This combination can be directly connected to the LI-250A Light Meter or LI-1400 Data Logger. The 2291 Millivolt Adapter should be ordered if the LI-193SA will be used with a data acquisition device or data logger that measures millivolts. The 2291 uses a 1210 Ohm precision resistor to convert the LI-193SA output from microamps to millivolts.
LI-193SA Spherical Quantum Sensor
2009S Lowering Frame
2291 Millivolt Adapter
2222UWB-3 Underwater Cable, 3 meters
2222UWB-10 Underwater Cable, 10 meters
2222UWB-30 Underwater Cable, 30 meters
2222UWB-50 Underwater Cable, 50 meters
2222UWB-100 Underwater Cable, 100 meters