Download Scanning Electron Microscope Operation

Beam Energy
If you know what elements to expect in your sample, look up the EDAX
voltage on the wall chart for the K, L, and M shell electrons for the sample
atoms and determine the highest energy of all elements in the sample.
Then set the electron beam voltage (EHT) at twice the highest electron
binding energy – limited of course by the 30 kV max beam voltage.
Turn off Chamber LED Illumination
Before executing the EDAX software, you must turn off the LEDs that
illuminate the interior of the stage vacuum chamber. The light from these
LEDs causes the X-ray detector to count large numbers of phantom Xrays, and confuses the energy calibration. You can turn off the LEDs by
sliding the illumination slider at the top of the Chamber Scope window all
the way to the left. The screen will go totally dark. If after that, the
window still shows a small spot of light, it indicates that the stage End of
Travel Sensor is illegally active. The only way to cure this is to re-initialize
the stage, which consequently requires re-establishing the SEM image at
your target.
Illumination Error Recovery
Recovering from the Stage End-of-Travel-Sensor illumination error
requires re-initializing the stage. To do this, record the current stage
location, manually drop the stage back to a safe distance from the
objective lens (Z~10 mm), and then open the “Stage” menu from the top
row of command menus. Find the Initialization command at the top of the
list and click on it. This will cause the stage to automatically drive to the
zero end of each axis and reset the stage zero location. When it finishes
this operation, it will have turned off the end of travel sensor illumination.
This fixes the interference with the X-Ray detector and the EDAX system
can work now. However, you have to move the stage to the previous
location (which you dutifully recorded before starting this operation), and
find the spot on your sample that you want to record a mass spectrum
from.
WARNING: Please do not drive the stage in Z by inputting numbers into
the digital move boxes – move it manually while watching the video
camera so that you won’t hit anything.
Title: Scanning Electron Microscope Operation
Author: Roger Robbins
The University of Texas at Dallas
Page 54 of 85
Date: 9/29/2015