Suppression Of Double Modulated Stray Light By Spectral Band Selection - ABB MB3000 Series Installation And User Manual

Suppression of double modulated stray light by spectral band selectionAppendix C Spectroscopy Background
high refractive index windows such as ZnSe that is placed at the sample focus.
Using lower refractive index windows such as BaF
sample focus and placing the cell at a slight angle to the beam all are measures that
help reduce double modulation stray light.
Here again the supplied grid attenuator, when placed strategically between the
sample and the interferometer, will greatly reduce double modulated stray light
since the double modulated light has to pass through the attenuator twice.

Suppression of double modulated stray light by spectral band selection

The MB3000 mid IR FTIR has a spectral response starting at about 500 cm
double modulated stray light can start to occur only at 1000 cm
same principle if highly linear absorbance response over a wide absorbance range is
desired say in the 2000 to 2500 cm
be eliminated completely from this region by filtering out the spectral response
below 2000 cm
3700 cm
3700 to 7400 cm
recommended to use a shorter wavelength cutoff detector which provides further
elimination of double modulation stray light while generally providing higher
sensitivity at the same time.
60
-1
. By the same token, in the MB3600, the spectral response starts at
-1
and hence there is no double modulation stray light over the range from
-1
. For higher frequency spectroscopy in the near IR it is
, placing the cell away from the
2
-1
region, then double modulated stray light can
-1
. The
-1
and higher. By the
AA003700-01 rev. G. 2.0