Extended Photosynthetically Active Radiation (ePAR) Sensor

R9 450 - R14 500


Apogee's new 380-760 nm Extended Photosynthetically Active Radiation (ePAR) are designed for making total photon flux intensity measurements of wider ranges than traditional PAR sensors that measure 400-700 nm.

The new Apogee ePAR sensor was created in 2021 to measure the newly defined 380-760 nm ePAR radiation range that emerging research is showing to be photosynthetically active beyond the traditional 400-700 nm range. Many next generation LED fixtures, the sun, and other light sources emit these extended photosynthetic wavelengths, but they have not been measurable by traditional PAR meters until now. Much of the transformative work to define the ePAR range was conducted by Dr. Shuyang Zhen and Dr. Bruce Bugbee at Utah State University's Crop Physiology Laboratory.

The ePFD sensor was created in 2020 to measure the total intensity of photons in the 340-1040 nm range. This wide measurement range is useful for applications like studying the photomorphogenic effect of UV, far-red, and even infrared security lights, which can affect certain plants during their dark periods. Because of the extra-wide measurement cutoffs of this sensor, it is not recommended for PAR measurements under any light source except LEDs where all wavelengths are known to be within the traditional 400-700 nm PAR or 380-760 nm ePAR range.

 PPFD Sensor


Spectral Response

The ePAR is an extended photosynthetically active radiation sensor with a spectral range of 380 to 760 nm ± 5 nm, which can be seen in the graph below.

Extended apogee ppfd sensor

Typical Applications

Total ePAR and ePFD intensity measurements over plant canopies in all growing environments, monitor and adjust grow lights, research plant morphogenic activity, and photobiology studies.

Accurate, Stable Measurements

Sensors are cosine-corrected to maintain their accuracy when radiation comes from low zenith angles. The sensors measure PFD with a cosine response accurate within ± 5 % at 75° zenith angle. Long-term non-stability determined from multiple replicate quantum sensors in accelerated aging test and field conditions are less than 2 % per year.

Rugged, Self-cleaning Housing

Patented domed shaped sensor head (diffuser and body) facilitate runoff of dew and rain to keep the sensor clean and minimize errors caused by dust blocking the radiation path. Sensors are housed in a rugged anodized aluminium body and electronics are fully potted.


To ensure accuracy each sensor is carefully calibrated in controlled conditions and traceable to NIST reference standards. The extended sensors are pre-calibrated for all light sources, though it is recommended SQ-620 series (ePFD) sensors are only used under LEDs.


The AL-120 Solar Mounting Bracket with Leveling Plate facilitates mounting the sensor to a mast or pipe. The AL-100 Solar Sensor Leveling Plate is designed to level the sensor while sitting on a flat surface or mounting to a surface.

Output Options

Available in multiple analog output options including 0 to 40 mV, 0 to 2.5 V, 0 to 5 V, and 4 to 20 mA ranges. Digital output options include a digital “smart” sensor that uses USB communication and custom software to interface directly to a computer, SDI-12, and Modbus protocols. Sensors are also available attached to a hand-held meter with digital readout. The analog versions of these sensors (SQ-610, SQ-620) work with our µCache Bluetooth Micro Logger.

High-Quality Cable

Pigtail-lead sensors feature an IP68, marine-grade stainless-steel cable connector approximately 30 cm from the head to simplify sensor removal for maintenance and recalibration. The cable is shielded-twisted pair wire with a TPR jacket for high water resistance, UV stability, and flexibility in cold conditions.


PPFD measurements over plant canopies in outdoor environments, greenhouses, and growth chambers.

Reflected or under-canopy (transmitted) PPFD measurements in outdoor environments, greenhouses, and growth chambers.


All Apogee products are backed by an industry-leading 4-year warranty.

Green Houston is an official distributor for all Apogee instruments in Africa, imported directly from the USA.

Please contact office@greenhouston.co.za for all Apogee sensors and variants.

Please note: Apogee products are imported from the USA and due to the fluctuating exchange rate, prices are not fixed and may be subject to change. Requesting a quote before placing an order is highly recommended.


Educational Video's

2021 Extended meter range meter explained