FEI Quanta FEG 250, User'S Operation Manual

Page: 139 / 228

Maintenance and Troubleshooting: Aperture Strip Module
8-7
• Installing the c-clip into the insert is done using both the aperture
tool and the injector/plunger tool. Use tweezers to insert the c-clip
into the injector tool, then use the injector tool to install the c-clip
into the aperture insert.
• To put on the o-ring, push it onto and over the top of the insert,
making sure not to roll or deform it in any way.
Aperture Strip Module
The objective apertures are holed on a Molybdenum strip which is
mounted on a metal holder. The strip has 5 aperture positions and
1 mm alignment hole in the frame. The strip comes aligned in a metal
module which is connected to the end of the Aperture rod by a screw.
The module is considered as a consumable and therefore would be
normally replaced when heavily contaminated. In some cases it is
possible plasma cleaning with any available plasma cleaner (in this
case follow the equipment instructions). There is also a heater in the
rod to assist cleaning / anti-contamination. All screws are made of
Titanium not to have any magnetic effect.
FIGURE 8-5 APERTURE STRIP MODULE
REMOVING THE APERTURE ROD
1. With the high voltage off, vent the specimen chamber.
2. If connected remove the heater cable from the outer end of the
rod.
3. Unscrew the end of the Aperture rod and carefully remove it from
the microscope.
Note:
Preparation to clean or replace apertures should be immediately
available as the specimen chamber has to stay at atmospheric
pressure for the duration of maintenance.