Thermo Scientific Apreo User's Operation Manual page 153

Detector Settings
• Select the GAD–ABS from the Detector Settings module / Detector
list box / GAD–ABS or GAD–CBS detector.
Choose the required diode segment(s) by clicking the relevant
radio button:
• All is the normal BSE image with suppressed topographical
contrast and maximum atomic number contrast.
• Inner / Outer uses shadows to create strong topographical and
atomic number contrast.
• A / B / C is the pseudo-topographical image with suppressed
atomic number contrast and maximum topographical contrast.
• Custom 1 / 2 can be set by a user by clicking the selected
segments to add signal to (+ yellow background) / subtract
signal from (– blue background) the overall detector signal.
Clicking on the same (+ / -) sign again turns the segment
background gray; this segment sends no signal.

Note
Setting segments to subtract signal is allowed only for Custom 2.
Set combination remains stored under the particular user.
• The Contrast button equalizes signals (contrast) from different
segments so they do not to override one another and have the
same contrast in different displays in which the GAD–ABS /
GAD–CBS detector is used.
Distribution of electrons collected by detector segments
changes with setting the working distance, lens mode and Beam
Deceleration mode.
It is also possible to set different segments in particular displays
and thereafter to use the Enhanced Image module / Mix 3 or Mix 4
tab to mix color coded signals to create color images.

Note
Whenever the GAD is selected, the optical display is paused (because
the CCD camera infra-red LED's are switched off so as to not emit
photons that might supersaturate the detector diode).
C O N F I D E N T I A L – limited rights
Revision A Feb 2018
System Options: Optional Detectors
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User Manual 7-7