FEI Quanta FEG 250, User'S Operation Manual, Page: 90 / 228

Operating Procedures: Detector Types and Usage
5-18
GASEOUS SECONDARY ELECTRON
DETECTOR (GSED)
The GSED is integrated into a flexible printed circuit board and plugs
into the signal connector behind the conical lens. It is used for general
wet imaging and for high pressure imaging with auxiliary gases.
FIGURE 5-6 GSED AND ITS CONFIGURATION
The overall image consists of a very pure SE signal with very little
BSE signal component, due to the detector design and chamber
geometry. This pure SE signal makes this detector best suited for
resolution imaging. The field of view is less than the LFD at the lowest
magnification. The lower magnification range is about 240× at 7 mm WD.
Installing and setting the GSED
1. With your gloved hand, grasp the detector by the rigid connector
end. Hold it with the detector head facing towards you, and the
yellow Torlon ring facing up.
2. Insert the detector (gold fingers facing forward) into the connector
located at the back of the chamber, behind the conical lens. This is
made easier by inserting the right side of the detector in to the
visible portion of the connector, then rotating the detector into
position. A keyed connector position prevents the user from
inserting the detector upside-down.
3. Place the yellow Torlon ring of the detector head under the lens
insert and press the detector head up onto the insert. This requires
little force and can be done with one finger. The yellow Torlon seal
should be fully in contact with the lens.
FIGURE 5-7 THE GSED INSTALLED
Signal
Connector
Flexible
printed
circuit
board
Mounting
collar