CLD

1
CLD
2

• With dry air produced ozone is mixed with sample
  gas.
• The mixture enters the reaction chamber, while
  the NO of the sample gas reacts to NO2
• NO O3 ? NO2 O2 h?
• A proportion of the reaction energy is emitted as
  infrared radiation (h?).

• The infrared radiation is detected, enhanced and
  transformed into the detector signal by the
  photomultiplier.
• The NO2 of the sample gas is converted into NO by
  the integrated converter and then measured in a
  separate reaction chamber.
• The difference between both measurements
  corresponds to the NO2 content of the sample gas.

3
CLD - Measuring Principle
The chemiluminescence is disturbed by Quenching
effects. They are caused by absorption of the
emitted radiation by other components and by
radiation-free energy loss due to collision
processes. Remedy Reduced pressure (35 mbar) ?
reduction of collision processes. Selection of a
measuring range (650-850 nm) with low foreign
absorption. Due to the high amplification factor
of the photomultiplier (1100.000) emission
flanks can be used.