Thermo Scientific SOLA II, Руководство пользователя

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Product Overview
Principle of Operation
2-4 SOLA II User Guide Thermo Fisher Scientific
The detector is based on the principle that SO
2
molecules absorb UV light and
become excited at one wavelength, then decay to a lower energy state
emitting UV light at a different wavelength. Specifically,
The sample inlet bulkhead draws the sample into the analyzer. The sample is
mixed with air and passes through a pyrolyzer furnace that oxidizes the sulfur
molecules in the sample to produce SO
2
. The sample then flows into the
fluorescence chamber where pulsating UV light excites the SO
2
molecules. The
condensing lens focuses the pulsating UV light onto a mirror assembly. The
mirror assembly contains four selective mirrors that reflect only the
wavelengths that excite SO
2
molecules.
As the excited SO
2
molecules decay to lower energy states, they emit UV light
that is proportional to the total sulfur concentration in the sample. The
bandpass filter allows only the wavelengths emitted by the excited SO
2
molecules to reach the PMT, which detects the UV light emission. The photo
detector, located at the back of the fluorescence chamber, continuously
monitors the pulsating UV light source to provide compensation for
fluctuations in the UV light source. The measured SO
2
concentration
(representing total sulfur in the sample) is processed, displayed on the front
panel display, and sent to the analog outputs.
Figure 2–2. Typical functional flow diagram
Principle of
Operation