Nox; Figure 10-1: M200E Sensitivity Spectrum - Teledyne 200E Instruction Manual

Theory of Operation
supplies the reaction cell with a large, constant excess of ozone (about 3000-5000 ppm)
from the internal ozone generator.
However, only about 20% of the NO
state. In addition, the excited NO
reaction cell (mostly other molecules but also cell walls) and transfer its excess energy to
its collision partner without emitting any light at all (Equation 10-3). In fact, by far the
largest portion of the NO
yield of usable chemiluminescence.
In order to enhance the light yield of the reaction, the reaction cell is maintained at reduced
pressure. The probability of a collision between the NO
increases proportionally with the reaction cell pressure. This non-radiating collision with the
NO * molecules is usually referred to as quenching, an unwanted process further described
2
in Section 10.1.5.2.
10.1.2. NO and NO
X
The only gas that is truly measured in the M200E is NO. Any NO
detected in the above process since NO
nescence.
In order to measure the concentration of NO or NO
NO and NO in the sample gas), the M200E periodically switches the sample gas stream
2
through a converter cartridge filled with molybdenum (Mo, "moly") chips (Figure 10-6)
156

Figure 10-1: M200E Sensitivity Spectrum

that is formed through reaction 10-1 is in the excited
2
can collide with another collision partner M in the
2
* returns to the ground state this way, leaving only a few percent
2
+
*
NO M
2
Determination
2
does not react with O
2
Model 200E Instruction Manual
→ +
NO M
2
* molecule and a collision partner M
2
2
to undergo chemilumi-
3
(which is defined here as the sum of
X
Eq 10-3)
contained in the gas is not
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