HALO Users Manual
Revision G
2
Figure 1-2 Ringdown Time
#
The computer-controlled system tunes the laser off the absorption peak for the sample
species to determine the “tau zero” value, equivalent to a zero baseline (Figure 1-3).
Figure 1-3 Absorption Spectrum
#
The concentration of the sample species is calculated (Figure 1-4) by comparing this “tau
zero” value to the ”tau measured” ringdown time.
#
These calculations are based on first principles and follow the Beer-Lambert Law.
0
10
20
30
40
50
60
70
80
90
100
1391.3
1391.8
1392.3
1392.8
Wavelength (nm)
$
(
%
sec)
&'(&$
zero
&'(&$
peak
