FEI Quanta FEG 250, User'S Operation Manual

Page: 165 / 228

System Options: Optional Detectors
9-17
The Quad BSED is mounted close to the (optional) X-ray detector
collimator, which must not be touched when changing detectors. It is
advisable to retract the EDX collimator when mounting / removing the
detector on / from the objective pole piece.
Detector Settings
Select the Quad BSED from the Detector Settings module /
Detector list box. Choose the required Mode from the list box.
• The Z Contrast (A+B+C+D) is the normal BSE image with
suppressed topographical contrast and maximum atomic number
contrast.
• The Topography is the pseudo-topographical image with
suppressed atomic number contrast and maximum topographical
contrast. Adjusted segment setting could be left / right rotated by
two buttons with circular arrows. This changes a direction of the
resulting image illumination.
• The Custom mode is used to define the segments to be used for
detecting. Right-click over the particular segment and select Add
(yellow color) / Substract (blue color) to add / substract the
segment signal or Turn Off (grey color) to switch the segment off.
Obtaining Image in BSE Mode
1. Install one of the diodes and select the corresponding Detector.
2. Close the chamber door and pump down the chamber.
When the Quad BSED diode is installed,
No Accessory must be
selected in the PLA Configuration dialogue when this appears.
3. When the Vacuum is ready, switch on the accelerating voltage and
slowly increase the contrast and brightness to obtain an image.
Note:
Whenever the Quad BSED is selected, the optical quad is paused
(because the CCD camera infra-red LEDs are switched off not to emit
the photons supersaturating the detector diode).
PHOTO MULTIPLIER TUBE /
BACKSCATTERED ELECTRON DETECTOR
AUTRATA, CENTAURUS (PMT-BSE)
See separate manual.
FIGURE 9-12 AUTRATA / CENTAURUS DETECTOR