Thermo Scientific 43i, Инструкция по эксплуатации

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System Description
Hardware
Thermo Fisher Scientific Model 43i Trace Level-Enhanced Instruction Manual 8-3
The flash lamp provides the ultraviolet light source that causes the
fluorescence reaction in the SO
2
molecules.
The condensing lens focuses light from the flash lamp into the mirror
assembly.
A set of eight mirrors selectively reflects only those wavelengths used in
exciting SO
2
molecules. This reflective filtering causes the radiation
reaching the detection chamber to be more intense and more stable
throughout the lifetime of the instrument.
The relay lens is used to optically couple the primary and secondary
monochromaters.
The circular baffle helps keep stray light from entering the detection
volume.
The flash lamp trigger assembly pulses the UV flash lamp at a rate of 10
times per second for improved signal-to-noise ratio and long term stability.
The lamp is operated in the pulsed mode for six major reasons:
•
Long life
•
High optical intensity – improved signal to noise ratio
•
Small size
•
Low power requirements – less than 1 watt
•
Long-term stability
•
Chopped signal processing – no dark current drift
In the reaction chamber pulsating light from the flash lamp excites the SO
2
molecules. A condenser lens collects and focuses light from fluorescing SO
2
molecules onto the mirror assembly.
Flash Lamp
Condensing Lens
Mirror Assembly
Relay Lens
Light Baffle
Flash Lamp Trigger
Assembly
Reaction Chamber