Teledyne T101 Operation Manual page 252

Principles Of Operation
SO
248
F
=
Where:
F
k
SO *
2
Therefore:
kF
*
  → 
2
Furthermore, the function (k) is affected by the temperature of the gas. The warmer the
gas, the faster the individual molecules decay back into their ground state and the more
photons of UV light are given off per unit of time.
Given that the absorption rate (a) of SO
result of:
• The amount of SO
from equation 10-2 above: concentration of SO
I
( ); path length of the UV light (
0
The amount of fluorescent light created which is affected by the variable
•
factors from equation 10-5: the amount of SO
decay (k) which changes based on the temperature of the gas.
The amount of fluorescent light emitted (F) is directly related to the concentration of the
SO in the Sample Chamber, when:
2
• the intensity of the light (
• the path length of excitation light is short (
the temperature of the gas is known and compensated for so that the
•
rate of SO *decay is constant (k)
2
there are no interfering conditions present (such as interfering gases or
•
stray light)
The Model T101 UV Fluorescence SO
circumstances.
The light path is very short.
•
The optical design reduces the effects of stray light geometrically and
•
spectrally.
A special hydrocarbon scrubber removes the most common interfering
•
gases from the sample gas.
• A reference detector measures the intensity of the available excitation UV
light and is used to remove effects of lamp drift.
Finally, the temperature of the sample gas is measured and controlled
•
via heaters attached to the sample chamber.
The net result is that any variation in UV fluorescence can be directly attributed to
changes in the concentration of SO
( )
k SO *
2
=
the amount of fluorescent light given off.
=
the rate at which the SO
=
amount of excited state SO
SO hv
+
2
is constant, the amount of fluorescence (F) is a
2
* created which is affected by the variable factors
2
x
) and;
I
) is known
0
Analyzer is specifically designed to create these
2
in the sample gas.
2
Teledyne ML - T101 Operation Manual
* decays into SO
2
in the sample chamber.
2
330 nm
; intensity of UV light
2
* present and the rate of
2
x
)
2 .