Extended Photon Flux Density (ePFD) Sensor

R9 450 - R14 100


Measure photon flux density (PFD) from 340-1040 nm

Apogee’s new extended-range photon flux density (PFD) sensors are for measuring the newest generation of LED grow lights with wavelengths outside the traditional 400-700 nm PAR range. Research has shown the value of adding UV and far-red LEDs to achieve various disease control and photomorphogenic effects. The extended range filter of the SQ-620 allows it to measure photons from UV and Far-red. The 1040 nm top cutoff also means the sensor will measure the thermal output of HPS fixtures and other broad-spectrum lights above the range that influences plants; therefore, the sensor is intended only for use in LED environments.

Please Note: 

This particular sensor should only be used for photon flux density measurements under LEDs. 

Apogee are discontinuing the “ePFD” line of sensors and meters that measures from 340 – 1040 nm. It is being replaced by the “ePAR” line which measures from 380 – 760 nm. The ePAR has a better spectral match the wavelengths of light that are photosynthetically active so it is a superior product to the ePFD sensor, and can be used under any kind of light. 



Spectral Response

The Extended Range PFD sensor (model SQ-620) has a spectral range of 340 to 1040 nm ± 5 nm. The extended spectral response increases the accuracy of LED measurements.

Graph of PAR meter extended range from apogee

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 full-spectrum sensors are pre-calibrated for all light sources.


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

Apogee currently offers one analog model available for sale on our website with multiple outputs and measurement ranges coming soon. Please call for availability. Sensors are also available attached to a hand-held meter with digital readout.

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

Photobiology Simplified with Dr Bruce Bugbee

Turning Photons Into Food