Apogee Instruments Quantum Sensors and Meters (500 Series) Product Announcement

It was recently discovered that Apogee Instruments quantum sensors and meters (500 series) manufactured prior to March 28, 2017 (see serial number ranges below) were measuring lower than the specified spectral accuracy under deep blue and violet lamps in the 400 to 420 nm range when compared to precision spectroradiometers. An investigation found a small manufacturing defect in the sensor optics that has now been corrected. We sincerely regret any problem and inconvenience this defect has caused for customers measuring light from deep blue or violet lamps. Apogee stands behind our products and will make this right for you.

What measurements are affected by this issue?

Not affected: Typical Broadband Lights.

Spectral errors were less than 2 % from broadband radiation sources, including sunlight, cool white fluorescent, metal halide, high pressure sodium, white LED fixtures, blue/red LED fixtures, and all other LEDs with peaks greater than 450 nm. No further action is required to update your current sensor/meter.

Partially affected: Deep-water measurements.

For users making deep-water measurements outdoors, errors from sunlight attenuation increases with depth, with an estimate of 4 % error occurring at 10 m. Please see the white paper for detailed error multipliers you can use to correct your data, or you can contact Apogee to have your sensor updated at no cost.

Affected: Deep Blue and Violet Lamps.

For users measuring lighting fixtures with a high percentage of output between 400 and 420 nm (for example, fixtures with only Actinic or Blue Plus T5 bulbs), measurements were 10 to 20 % low. Lighting fixtures containing only these bulbs are rarely used, as they are usually mixed with broader spectrum bulbs, like standard T5 bulbs. When Actinic and Blue Plus bulbs are mixed with broader spectrum bulbs, measurement errors are reduced to less than 5 % and may not be considered significant to many users (see accompanying white paper for mixed fixture errors and correction multipliers). If you are measuring fixtures with bulbs that only output in the deep blue/violet range, you can either use the correction multipliers provided in the white paper to correct your data, or contact Apogee to have your sensor updated at no cost.

If you have any questions about this announcement, please contact Apogee Instruments Technical Support department at techsupport@apogeeinstruments.com or (435)792-4700.

Serial Number Ranges:

MQ-500 S/N 1001-1457

MQ-510 S/N 1001-1109

SQ-500 S/N 1001-1227

SQ-520 S/N 1001-1359

SQ-514 S/N 1001-1002

To learn more about this issue, please click here to read a whitepaper created by Apogee’s engineers.