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and forth through focus, from underfocus to overfocus) and observe if a "streaking"
pattern emerges and changes direction between under- and overfocus. If the astigmatism
has been corrected, the specimen will vary only in focus, with no streaking pattern
evident. Repeat steps 4 and 5 until this state is achieved.
f. PRESS the Stig button again to return to the TEM Brightfield page.
13. Collecting Spectra with EDAX EDS and Genesis Software
A. Collect spectra
a. DOUBLE CLICK on the EDAX Genesis icon on the PC desktop to open the program.
b. TILT the goniometer
by +15°.
c. It is important to
optimize the counts
per second (CPS) and
dead time (DT).
d. To change the CPS,
change the Spot Size.
Spot
Size
recommended.
e. Generally, to change
the DT, adjust the
Amp Time. DT should
be between 20 to
40%. As a rule of
thumb,
SELECT
Amp Time of 25.6 or 51.2 µs.
f. FOCUS the image.
g. RETRACT the Objective Aperture.
h. PRESS the Clear button to remove old peaks.
i. PRESS the Collect button to start to collect a new spectrum. To STOP the collection,
PRESS Collect again.
6
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