Electron microscopy
 
GIF Gate Valve
- Practical Electron Microscopy and Database -
- An Online Book -
Microanalysis | EM Book                                                                                   http://www.globalsino.com/EM/        

This book (Practical Electron Microscopy and Database) is a reference for TEM and SEM students, operators, engineers, technicians, managers, and researchers.
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For both GIF imaging and spectrum acquisition, we need to make sure:
         i) The controllers (e.g. multi-scan camera controllers) are turned on.
         ii) A suitably intense electron beam is placed in the center of the GIF camera. In this case, we also need to verify that the electron beam is not deflected out of the center of the GIF camera when the viewing screen is raised.
         iii) Make sure the GIF gate valve is not stuck in the closed position. A control line for the gate valve should have a black label, while the other one a red label. When the black line is pressurized the gate valve should be open, when the red line is pressurized the gate valve should be closed.
         iv) The Primary Energy in the FilterControl software is set to the operating energy of the TEM.
         v) Check the communication between the FilterControl software and the Gatan Instrumentation Bin (GIB). If the communication is correct, the yellow LED on the front panel of the GIB should be on or flashing.
         vi) The Drift Tube Voltage is turned off or set to 0; otherwise, the image or spectrum can be too weak to be visible.

The level of GIF camera chamber vacuum can be evaluated by comparing the current camera chamber vacuum reading to the good ones recorded historically. If the vacuum is poor, one step in the examination procedure to locate any leaks is to locate the control lines for the gate valve. One should have a black label, the other one a red label. Normally when the TEM is fully pumped down, the black control line should be pressurized and the gate valve should be open. When the TEM is not fully pumped down, the gate valve may be closed so that the red control line should be pressurized. With the TEM fully pumped down, it will swap the gate valve control lines to close the gate valve.

 

 

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