SQ-640-SS Quantum Light Pollution Sensor

The SQ-640 Quantum Light Pollution sensor is a self-powered sensor. The sensor features a rugged, aluminum housing that is fully-submersible and built to withstand harsh conditions, and high-quality cable terminating in pre-tinned pigtail leads for easy connection to dataloggers and controllers. The sensor cable includes an IP68 marine-grade stainless-steel cable connector to simplify sensor removal and replacement from permanent installations for maintenance and calibration. Typical applications of Quantum Light Pollution sensors include incoming PFD measurements over plant canopies in indoor greenhouses or in growth chambers, and reflected or under-canopy (transmitted) PFD measurements in the same environments. Since the detector on this particular Quantum Light Pollution sensor is sensitive to radiation with wavelengths up to 1100 nm, beyond the range of wavelengths that influence plants, we recommend only using the SQ-640 sensors in indoor grow environments utilizing LED lights.

The analog version of this sensor (SQ-640) comes with the inline cable connector placed 30 cm from the sensor head for either standard use as a long-cable pigtail sensor, or for use with our microCache Bluetooth Micro Logger by unscrewing the connector, discarding the long section of cable and then screwing the sensor to the mating connector on the microCache.

How is the SQ-640 different from previous Apogee quantum sensors?
The SQ-640 is an extended range photon flux density (PFD) sensor with a spectral range of 340 to 1040 nm ± 5 nm, which can be seen in the graph below.

Where is the SQ-640 used?
Many plants are affected by interruptions in dark periods even by extremely dim light. Apogee’s new Quantum Light Pollution Sensor is designed to detect photons from 340-1040 nm that are below the sensitivity level of a typical quantum sensor. Detecting stray photons that disrupt the night is critical in preventing negative effects in plan

Specification

• Power Supply: Self-powered
• Sensitivity: 1 mV per µmol mˉ² sˉ¹
• Calibration Factor: 1 µmol mˉ² sˉ¹ per mV
• Calibration Uncertainty: ± 5 %
• Measurement Range: 0 to 200 µmol mˉ² sˉ¹
• Measurement Repeatability: Less than 0.5 %
• Calibrated Output Range: 0 to 200 mV
• Long-term Drift (Non-stability): Less than 2 % per year
• Non-linearity: Less than 1 % (up to 200 µmol mˉ² sˉ¹)
• Response Time: Less than 1 ms
• Field of View: 180°
• Spectral Range: 340 to 1040 nm ± 5 nm (wavelengths where response is greater than 50 %)
• Directional (Cosine) Response: ± 2 % at 45° zenith angle, ± 5 % at 75° zenith angle
• Azimuth Error: Less than 0.5 %
• Tilt Error: Less than 0.5 %
• Temperature Response: -0.11 ± 0.04 % per C
• Uncertainty in Daily Total: Less than 5 %
• Housing: Anodized aluminum body with acrylic diffuser
• IP Rating: IP68
• Operating Environment: -40 to 70 C; 0 to 100 % relative humidity; can be submerged in water up to depths of 30 m
• Dimensions: 30.5 mm diameter, 37 mm height
• Mass: 140 g
• Cable: 5 m of two conductor, shielded, twisted-pair wire; TPR jacket; pigtail lead wires; stainless steel (316), M8 connector located 25 cm from sensor head
• Warranty: 4 years against defects in materials and workmanship
• Manufactured: Assembled in the USA