Ocean Optics OOIIrrad-C - Manual (Page 17)

3: Controls and Menus
The reflection of a solution is calculated using the following equation:
…where S
λ
is the sample intensity at wavelength λ , D
λ
is the dark intensity at wavelength λ , and
R
λ
is the reference intensity at wavelength λ .
• Relative Irradiance Mode – Allows you to graph the irradiance intensity of the sample being
measured. You can use Relative Irradiance Mode after you calibrate the spectral response of your
system and take a dark scan (see Scope Mode). Relative Irradiance Mode calculates the irradiance
of a spectrum in relation to other intensities measured in that spectrum.
Dark and Reference Sample Controls
The Dark and Reference Sample Controls allow you to store dark and reference samples with a few clicks
of the mouse.
Disable or block the light source completely when taking a dark sample. Stray light will affect the
calculations OOIIrrad uses to measure your samples, and a corrupted dark sample will result in incorrect
measurements.
Reference samples should be taken with the same setup used to measure samples. For example, if you are
measuring a substance in water in a cuvette, your reference should be taken with the cuvette and water in
place, minus the substance to measure. This allows the OOIIrrad-C to account for variations in each
sampling system and calculate and display an accurate measurement.
The following Dark and Reference Sample Controls are available:
Item Description
Subtract Dark check box
Once you store a dark and reference sample, you can enable this option to
remove the dark values from the measured sample. Useful only in Scope
Mode.
Store Dark button Brings up the Store Dark screen, which allows you to store a dark sample.
Ref button
Brings up the Store Reference screen, which allows you to store a
reference sample.
Magnification Controls
Magnification Controls allow you to alter the manner in which the measured data is displayed.
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