Instrument Support Level 3
2B Technologies 306 Ozone Calibrator
Not Applicable
Calendar
2B Technologies 306 Ozone Calibrator
Ozone is generated and measured by a dual cell UV photometric gas analyser manufactured by 2B Technologies (Model 2B 306).
The 2B Technologies Model 306 Ozone Calibration Source™ is a portable source of ozone that allows you to calibrate any ozone monitor. The instrument scrubs ozone from ambient air and produces any mixing ratio of ozone in the range 30 to 1,000 ppbv. The desired ozone concentration is chosen from the easy-to-use menu using a rotary select switch. The total output flow rate is 3.0 L/min volumetric, and the ozone mixing ratio is controlled so as to be independent of ambient temperature, pressure and humidity. This instrument is brought in-line with ozone calibrator 1 which is itself calibrated annually using the primary standard reference photometer #2 (SRP#2) from the National Physical Laboratory (NPL) (traceable through the National Institute of Standards and Technology (NIST). This allows the bias on a full range of ozone values to be evaluated.
This instrument is run as part of the COZI Laboratory set-up. It is run almost continuously to enable information about its long-term stability to be obtained. The instrument is calibrated regularly and is traceable to the Global Atmospheric Watch scale. Users are invited to calibrate their ozone instruments using this facility.
Ozone is generated by UV photolysis of O2 at 185 nm and measured by a dual cell UV photometric gas analyser. The instrument is manufactured by Thermo Scientific (Model 49i-PS).
To measure the ozone concentration generated, the sample air is drawn continuously through an optical absorption cell where it is irradiated by monochromatic light at 253.7 nm from a stabilized low-pressure Hg discharge lamp. The absorption of this radiation by the sample air is a measure of the ambient air ozone concentration. To avoid interference from other gases absorbing light at the same wavelength and from instability in the light source, an ozone catalytic converter is used to selectively remove ozone from the sample stream either in the sample cell by using another parallel sample cell.
The instruments’ parameters (cell pressure, flows, intensities, etc) are logged continuously to allow long-term evaluation of the instrument.
This instrument is checked against the NIST calibrated transfer standard (ozone calibrator 1) also held at the COZI-Lab and brought in-line with it at least every 4 months.
Ozone calibrator 1 (Model 49I-PS S/N: 0703820627) is held at the COZI-Lab, University of York, and is itself calibrated annually using the primary standard reference photometer #2 (SRP#2) from the National Physical Laboratory (NPL) (traceable through the National Institute of Standards and Technology (NIST). 3% uncertainty is acceptable for reference to standards e.g. to the SRP.
Data from instruments that are part of a laboratory do not archive their data to CEDA and so do not have to conform to any AMOF standard.
It is not possible to log generated ozone data (ppbv) but lamp intensity (arbitrary units) and other parameter data from the calibrator can be provided for the period of time that the user has accessed the facility.