Measuring Photon Active Radiation (PAR)

Photon active radiation is defined in the spectral range 400nm and 700nm expressed in mole of photons per square meter per second. Photo active radiation is an important measure to quantify photo synthetic response (Photosynthesis) which drives the photo chemical process on plant growth.


The quantum flux can be measured with the PAR sensor ML-020P which has a response equivalent to the action spectrum of a plant. The most accurate measurement solution if offered by the MS-720 portable spectroradiometer which measures the effective irradiance in 10nm bands throughout the action spectrum.

HOW-TO Application Guide


Common applications are plant growth studies, lightning control of assimilation lamps, light distribution of light below the canopy.


The spectral irradiance measured allows to calculate with different actions spectra applicable to the plant species.