Brewer MkIII Spectrophotometer

  • High wavelength accuracy
  • Appropriate wavelength range
  • Excellent stray light reduction
  • Superior long-term stability     
  • Automated celestial tracking  


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Brewer MkIII Spectrophotometer

The BREWER Spectrophotometer consists of a weatherproof spectrophotometer, azimuth tracker and stand. It provides near simultaneous observations of the total ozone column, SO2, and UV spectra.

The two-axis tracking, appropriate filter selections, on-board wavelength calibration and data logging are managed through internal electronics and an IBM compatible host computer. Control software for the PC enables 24 hr scheduling and remote unattended operation.

Ultraviolet (UV) radiation has been linked to skin cancer, skin aging, cataracts, and immune system suppression in humans and animals. In plants, enhanced UV radiation exposure has lead to crop damage and reduced yields.

From the point of view of risk assessment, exposure to UV radiation represents a large potential hazard. Although the necessity of UV monitoring is clear, the nature of the radiation and our sensitivity to it pose data collection challenges. If left un-addressed these challenges could leave our under-standing of future UV trends and impacts uncertain.

This is particularly true with damaging ultraviolet (DUV) studies. Unless the spectrum of solar UV is well known it is difficult to relate UVA and UVB intensities to bio-logical responses. For reliable solar spectral UV irradiance measurement, instrumentation must possess specific qualities. The BREWER Spectrophotometer exemplifies these qualities and provides the means to understand solar UV radiation and its current and future impact on the biosphere. 

MkIII Brewer Recommendation by Environment Canada
Environment Canada (EC) recommends the Mark III Brewer Ozone Spectrophotometer as significantly superior to the MkII and MkIV Brewers for the measurement of solar radiation and Ozone in the Ultraviolet (UV) region of the spectrum. This is because of the much improved stray light performance of the double-monochromator optical system used in the Mk III compared to the single-monochromator of the MkII and MkIV.

For this reason Kipp & Zonen no longer produces the MkII and MkIV models and for a number of years has only manufactured the MkIII Brewer. Of course spares, service and factory support continue to be available for all models of Brewer.

MkIII Brewer Operating Software
There are several versions of the GW-Basic PC operating software available for the Brewer Spectrophotometer. The latest version that is fully tested and approved by Kipp & Zonen for the ‘single-board’ Brewer MkIII is v3.75f. This is the version currently supplied with new Brewer MKIII instruments.

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Measurement method Dual spectrometer with PMT detector
Resolution 0.6 nm
Wavelength range 286.5 nm to 363 nm
Wavelength stability 0.01 nm (over full temperature range)
Power supply 230 VAC or 115 VAC
Operational temperature range -20 ºC to +50 °C
Operating temperature range, with cold cover -50 ºC to +50 °C
Total column measurement Ozone and Sulphur Dioxide
UV measurement Spectral, plus UVA, UVB, UVE, UVI


  • How often should my Brewer be calibrated?
    • For the Brewer spectrophotometer, regular recalibration is necessary for the reliability of the Brewer’s Ozone measurements. The World Meteorological Organisation (WMO) recommends that each Brewer is calibrated at least once every two years. The Brewer is a stable instrument and drifts in the instruments can be monitored and corrected because of the diagnostic tests such as Standard Lamp and Dead Time measurements.

      Some Brewer users prefer to have their Brewers calibrated every year. By doing this, they assure their Brewer data is of the highest quality. Drifts in the instrument are corrected sooner and the regular check with a reference Brewer increases the reliability of the data.

      If you would like to discuss calibration of your Brewer at the factory or at your location please contact us.

      Is your question still unanswered? Contact Support
  • The Brewer software says “LAMP NOT ON, HG TEST TERMINATED”. Should I replace the lamp?
    • The Brewer software will give this error message when it tries to make a HG measurement but cannot see the light of the Mercury lamp. There are several causes why the Brewer could give this error message. One of the motors could be in an incorrect position, so that the Brewer does not see the light. The PMT could not be measuring correctly or the lamp could need replacement.

      The first step in troubleshooting is doing a full reset (RE command) in the Brewer software. Then try to perform the HG test again.

      If the HG test still returns the error message one should find out if this also occurs for tests with the standard lamp. Type SL<enter> in the Brewer software.

      If Both the HG test and the SL test fail, then either a motor is not moving correctly or there is a problem with the PMT/photon counting circuitry. Use the maintenance manual for further troubleshooting.

      If the SL works but the HG fails, then there might be a problem with your lamp. For single board Brewers: Type AP to get the voltage of the Mercury Lamp (HG lamp). The voltage should be around 10 V. If the Voltage is off by 2 Volts, one should inspect the lamp.

      The HG or mercury lamp is the lowest lamp in the lamp housing. Usually, if the lamp needs replacement, the glass will have black spots or the filament will be broken.

      If the lamp needs to be replaced, do not touch the quartz envelope with your hands. Use a tissue or a piece of cloth. The lamp should be tightened firmly. Also, from the top, both filaments should be visible.

      Is your question still unanswered? Contact Support
  • How does the Brewer compensate Ozone measurements for temperature?
    • The Brewer instrument is capable of operating in different conditions from the tropics to the Antarctic. As the Brewer is used outside the whole year round, its Ozone measurements should not have any temperature dependency.

      During the factory testing of the Brewer it undergoes a test in the temperature chamber from 0°C to +45 °C. Standard Lamp measurements are taken throughout this entire temperature range. This is a simulated Ozone measurement based on the halogen lamp inside the Brewer. Although the intensity of the lamp does change with temperature, the wavelength shift is negligible.

      After the temperature test, the data of the SL measurements is analysed. During the analysis, the temperature correction coefficients are created. These coefficients compensate for the change in spectral response of the Brewer at the Ozone wavelengths. With the coefficients installed in the Brewer software, the Ozone measurements will not be affected by the temperature of the instrument.

      Is your question still unanswered? Contact Support
  • When and how should I clean the Brewer’s azimuth tracker drive?
    • The Brewer azimuth tracker has a driving mechanism based on friction between the drive shaft and the drive plate. These items will get dirty over time and the azimuth tracker is likely to slip. This can be noticed by a tracker discrepancy after AZ or SR tests.

      The drive mechanism can be cleaned by using a clean lint-free cloth with alcohol or with “garage” soap (soap with grains of sand in it). Switch the tracker power off! Remove the rear tracker cover (the cover on the side opposite to the power switch). Use the cloth with alcohol or soap to rub the dirt off the drive plate and the drive shaft. Rotate the tracker to clean the entire drive plate. Be careful not to break the wire of the safety switch. After cleaning the entire drive plate and shaft, rub them once more with a dry piece of clean lint-free cloth to remove any remaining residue of soap/alcohol.

      When this is done, rotate the tracker to aim the Brewer approximately at the sun . Put the tracker cover back on and switch on the tracker power. Now the Brewer needs to perform some tracker resets. In the Brewer software, type “PD AZ SR 10” to perform these resets. Watch the data to check that the tracker resets without discrepancies and then put the Brewer software back into its normal schedule.

      Is your question still unanswered? Contact Support


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