Serinus 44 User Manual 3.0
The ozone destroyer coil uses high temperature (~325°C) and a catalyst to removes ozone from the
instruments exhaust.
The heated core is controlled by the main controller PCA and kept at a stable temp ~325°C with
feedback from the thermocouple.
1.5.9 External NH
3
converter (thermal oxidiser)
Ecotech recommends the use of the HTO 1000N thermal oxidizer. HTO 1000N employs both catalytic
and thermal principles in the conversion of NH
3
to NO and NO
2
. The converter efficiency is normally
between 88-94% at a temperature of 680°C. The HTO 1000N is connected to the Serinus 44
instrument through the Auxiliary ports, on the rear of the instrument (refer to Section 2.3.1). For
more information on the HTO 1000N refer to the HTO 1000 manual. If you are using your own
external converter refer to its manual for further information.
1.5.10 Pressure Sensor PCA
There are two pressure sensor PCA’s that are used to check for flow and correct the instrument
readings for pressure variations. One is located on the auxiliary valve manifold, upstream of the
critical orifice (Manifold Pressure) and the other is located on the reaction cell downstream of the
critical orifice (Cell Pressure).
1.5.11 Reaction Cell
Reaction cell
The reaction cell is where O
3
and NO mix to create a chemiluminescence reaction, which emits
photons. A portion of this light is filtered to a specific wavelength region (>665nm) by the optical
bandpass filter and measured by the PMT.
Optical Bandpass Filter
The optical bandpass filter is constructed of coloured glass that only allows the transmission of light
above 665nm. It is used to prevent measurement of interfering compounds.
1.5.12 Optical Bench
Photomultiplier (PMT)
The PMT detects the amount of light reaching its sensors. The selective filtering of light reaching the
PMT allows direct measurement of NO in the cell.
PMT Cooler
The PMT cooler ensures that the PMT is operated at a constant 13°C. This reduces the measurement
noise of the PMT.
PMT High Voltage Supply and Preamplifier Module
This is a single component within the PMT housing. Its function is to supply high voltage to the PMT
and to amplify the photocurrent signal from the PMT.
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