Serinus 51 User manual 1.0
Introduction
5
• The radiation (214nm) is focused into the fluorescence cell where it interacts
with SO
2
molecules and emits photons uniformly in all directions.
• A portion of the fluorescence is collected and filtered.
• Wavelengths at 310-350nm pass through the filter where they reach the
photomultiplier and record a signal.
• A reference detector monitors the emission from the zinc lamp and is used to
correct for fluctuations in lamp intensity.
Figure 2 Optical measurement theory
• Air drawn from the Background Port is scrubbed via charcoal and then passed
through a particulate filter. This air is then available for use by the
Hydrocarbon Kicker and is also used to perform zero background adjustments.
1.4.2
Kalman filter theory
The Serinus analyzer series use the advanced digital Kalman filter. This filter
provides the best possible compromise between response time and noise reduction for
the type of signal and noise present in ambient air analyzers.
The Kalman filter enhances measurements by making the filter time base variable,
depending on the change rate of the measured value. If the signal rate is changing
rapidly, the instrument is allowed to respond quickly. When the signal is steady, a
long integration time is used to reduce noise. The system continuously analyzes the
signal and uses the appropriate filtering time.
1.5 Instrument description
The Sulfur Dioxide analyzer consists of five main assemblies:
• The pneumatics to transfer sample and exhaust gas
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