Qwave User Manual
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may not be as accurate as later measurements. Therefore, for precise measurements we
recommend not to use the auto-exposure feature and to set a fixed exposure time
instead.
Wavelengths
The mapping of the individual pixels of the spectrum to wavelengths is done using a
third-order polynomial. The four parameters for this function are measured during
manufacturing and stored in the device. Usually, this wavelength calibration does not
However, if the ambient temperature has changed substantially, if the device has been
used for a very long time or if you just would like to make sure that the wavelengths are
really correct, you can recalibrate the wavelength if you have a suitable light source with
several sharp atomic emission lines. These wavelength calibration sources are usually
low-pressure gas discharge lamps filled with Krypton, Neon, Mercury, Argon or Xenon
gas.
To recalibrate, take a spectrum of this light source first. Make sure that the relevant peaks
Menu.
list, you need to supply your own calibration lines. In this case, please take a look at the
CalibrationLines xxx.dat
create a new similar file containing the spectrum lines of your light source.
e tries to match
the peaks in the measured spectrum and the given spectrum lines for your light source
automatically. Not all of the given spectrum lines have to be present in the measured
spectrum, but all measured peaks must be known spectrum lines. If a match has been
found, the average deviation is displayed. If the match seems to be successful, it is
displayed in green, otherwise in red. You can also graphically display the deviations by
fully been identified,
device.
Dark Spectra
Inside the Qwave spectrometer, the spectra are detected with a CCD line sensor. Like all
image sensors, this sensor detects a small signal even if there is no light entering the
spectrometer. This signal depends on the individual pixel, the exposure time and the
temperature. In order to obtain
from the actual measurement.
