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Teledyne API T703 Calibrator Operation Manual Theory of Operation
173
UV
Source
ABSORPTION TUBE
UV Detector
Sample Gas OUT Sample Gas IN
Window
Window
Absorption Path Length = 42 cm
Photometer
Pre amp
PCA
O-5 VDC
analog signal
to
Motherboard
Analog current
signal is output by
Detector
Figure 9-19: O
3
Photometer Absorption Path
9.6.1.4. Interferent Rejection
It should be noted that the UV absorption method for detecting ozone is subject to interference from a number of
sources. The has T703’s photometer been successfully tested for its ability to reject interference from sulfur
dioxide, nitrogen dioxide, nitric oxide, water, and meta-xylene.
While the photometer rejects interference from the aromatic hydrocarbon meta-xylene, it should be noted that
there are a very large number of other volatile aromatic hydrocarbons that could potentially interfere with ozone
detection. If the T703 calibrator is installed in an environment where high aromatic hydrocarbon concentrations
are suspected, specific tests should be conducted to reveal the amount of interference these compounds may
be causing.
07223B DCN6378