Ametek Western Research IPS-4, Руководство пользователя

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1-6 | IPS-4 Dual Bench (UV / IR) Analyzer
Non-Dispersive Infrared (NDIR) Photometer
Basic Analytical Theory
The NDIR Optical Bench measures transmittance, T
( )
λ
l
, over one or more
bands of wavelength,
( )
λ
l
. Transmittance is the ratio of the transmitted
power (originating from the source),
( )
λ
l
( )
λ
l
, to the incident power,
( )
λ
0
l
( )
λ
l
for
each wavelength (see Equation 1.1).
The NDIR Optical Bench operates in the infrared (1–5 microns) wave-
length range of the electromagnetic spectrum.
Optical Bench Design
An Optical Bench is composed of four main components:
• A source EM radiation (or “light”) in the wavelength region of interest.
• A Measuring Cell with windows capable of transmitting light in the
region of interest and compatible with the sample composition;
• A wavelength selection device to isolate wavelengths of interest for a
specific application;
• A detector (or sensor) that is sensitive to the wavelength region. The
combination of (3) and (4) is also referred to as a spectrograph.
The combination of the wavelength selection device and detector is
also referred to as a spectrograph. Figure 1-2 illustrates the complete
optical path from source to detector for the NDIR Optical Bench.
CONDENSING
Figure 1-3.
Analyzer light path,
NDIR schematic.

NOTE