UVA Sensor (UVA-BTA)

Specifications and User Guide

Troubleshooting

  • Primary Test: Are you using the UVA Sensor to check UVB light? Confirm that the sensor is appropriate for the experiment.
  • Secondary Test: Take readings outdoors in the sunlight with and without a barrier, such as a piece of cardboard.

Additional Troubleshooting

Specifications

  • UV peak sensitivity: one volt per 3940 mW/m2 at 340 nm
  • Wavelength sensitivity region, approximate: 320 to 390 nm (320 to 375 nm, half-sensitivity points)
  • Dimensions: 21 cm by 2 cm diameter
  • Typical Resolution: 5 mW/m2
  • Time response: ~ 2 seconds to reach 95% of final reading
  • Stored calibration coefficients: slope (gain) = 3940 mW/(m² V); intercept (offset) = 0

Calibration

Calibrate? No. The sensor is set to the stored calibration before shipping. It is quite difficult to calibrate a UV sensor to read in absolute units, since you must have a source of known UV intensity and spectral distribution. More often, you will simply want to calibrate the sensor in terms of a relative intensity as noted below.

  1. Cover the tip of the UVA Sensor with a clean opaque object.
  2. Select the calibration option of the program you are using.
  3. Enter 0 (zero) as the first known intensity, then click or tap Keep.
  4. Now allow full UV intensity to strike the sensor.
    1. Since the orientation of the sensor affects the reading, it is best to hold the sensor in place with a ring stand or other clamp.
    2. To point the sensor directly at the sun, make the shadow of the sensor tube as small as possible.
  5. Enter 100 as the next known intensity, then click or tap Keep.
  6. Exit the calibration dialog. Measurements of the sensor will be relative to this second intensity.

For more information on calibration, see How do I calibrate my sensor?

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Published: September 26, 2013. Updated: May 1, 2025.