INFICON Composer Gas Concentration Controller - Manual (Page 66)

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Composer Operating Manual
NOTE: Long term use of the Composer with some of the materials listed in
Table 3-1 may not be possible. The user is responsible for ensuring
compatibility of use for all materials.
Figure 3-1 When the Specific Heat Ratio for a Gas is Unknown it is Generally
Better to Overestimate the Specific Heat Ratio
3.1.5 What is the Ideal Operating Environment?
In an ideal environment none of the parameters that influence the concentration
measurement change. Most Reactors can be configured so that the pressure
and flow through the Transducer are held constant by independent controllers.
In this way the Precursor’s Fluence into the Reactor can be maintained or
changed without altering the total flow and pressure through the Transducer.
This is also considered good practice for Reactor design. Leave the Instrument
System on at all times; it is always ready to immediately function with best
accuracy and we have not seen deterioration through continuous use. Since all
Reactors are in environmentally controlled rooms, the small influences due to
ambient temperature changes are of no concern.