User`s guide

Set Bias Levels
2.3 Set Bias Levels
In 4-channel CCD readout, the entire CCD sensor is divided into 4 sectors
(called quadrants). It is common that each quadrant has a different bias level.
This can result in CCD images with visible quadrant (like a chess board
pattern).
Under the Camera menu (Figure 2-3), Set Bias Levels routine automatically
measures and sets the bias for each quadrant. The bias setting is written to the
First Light Controller. This will remove the majority of the image contrast from
quadrant to quadrant in an evenly illuminated flat field image and maximize the
dynamic range.
The Set Bias Levels should be run before the linearization procedure (next
section) and after the camera is cooled. It is not necessary to run Set Bias
Levels again.
When running this routine, it does not matter if the viewing screen is raised or
not since the automatic procedure blanks the beam on the CCD as needed.
UltraScan User’s Guide Reference Series Rev 1.0 2-5