Apogee Instruments Quantum / PAR Meters
Measure photosynthetically active radiation (PAR, PPF, PPFD) from the sun or electric lights in μmol m-2 s-1
Apogee Instruments quantum sensors measure photosynthetic light levels in both air and water, combining accuracy and durability at an affordable price. The sensor heads feature a unique blue diffuser that reduces spectral error to less than 5% for sunlight (direct, diffuse, under plant canopy, reflected from plant canopy) and common electric plant lights (fluorescent, metal halide, high pressure sodium), and less than 10 % for LEDs (blue, green, red, cool white, neutral white, and warm white). You can read more about using our quantum sensors with various light sources in our Knowledge Base.
Apogee’s quantum sensors are the culmination of over 16 years of field-testing and feedback from researchers worldwide. The sensor heads are potted solid with no internal air space for use in all climate conditions. In addition, all Apogee designs are subjected to brutal accelerated aging tests to ensure reliability and precision even under the harshest of conditions.
Each Apogee quantum sensor is carefully pre-calibrated to NIST standards in carefully controlled conditions. Our stock models are ready to go out of the box and come in several configurations readily compatible with most data-loggers. Our custom options can provide maximum flexibility by offering different multipliers, outputs, and cable lengths. With Apogee, you are dealing directly with the manufacturer and we can work with you to deliver quantum sensors that fit your specific application.
For reference, a quantum refers to the amount of energy carried by a photon. Quantum meters approximate the quantity of photons between 400 and 700 nanometers. Photosynthesis is largely driven by the number of photons between these wavelengths. Photosynthetically Active Radiation (PAR) is also called the Photosynthetic Photon Flux (PPF) or Photosynthetic Photon Flux Density (PPFD) and the units are μmol m-2 s-1 (micromoles of photons per meters squared per second).