Ocean Optics SpectraSuite - Manual (Page 101)

7: Processing Menu Functions
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Absolute Irradiance
Select Processing | Absolute Irradiance | Absolute Irradiance to create a new graph of spectral data
Absolute Irradiance mode. You can also click
in the Data Display toolbar to use the wizard to create
an Absolute Irradiance graph.
Absolute Irradiance Mode calculates the true irradiance of a spectrum, displayed in actual W/cm^2/nm
(or W/nm when using an integrating sphere) incident on the probe’s collection area. You do not need to
store reference spectrum first since absolute irradiance is not relative to another measurement. However,
you must store a dark spectrum and have a calibration file before you can measure absolute irradiance.
If your spectrometer was calibrated by Ocean Optics, you should have received a CD containing the
Radiometric Calibration Files specific to your spectrometer. If you do not have these files, then you must
create your own spectrometer calibration files using calibrated light sources that have lamp files for
absolute irradiance.
See Experiment Tutorials for information on conducting an experiment in Absolute Irradiance mode.
Collection Area
Select Processing | Absolute Irradiance | Collection Area to enter the specifications of the collection
area.
The Collection Area dialog box offers the following options:
 Use Integrating Sphere – Enable this option only if one of the following applies:
 You have an integrating sphere and the proper calibration light source to calibrate your system.
 The light source being measured is completely inside the integrating sphere. If you are using a FOIS-
1 integrating sphere, you must use the LS-1-CAL-INT calibrated light source to calibrate your
system. Otherwise, you must have the complete system with the integrating sphere calibrated by
Ocean Optics.
Once your system has been calibrated, if the light source will not be located within the integrating
sphere, you must enable the Fiber Diameter option and enter a value (in microns) equivalent to the
diameter of the opening in the integrating sphere that is capturing the light. See Fiber Diameter below
for more information.
 Collection Area – If you know the actual collection area, enter it here. The default is 1.