3-6
Step 7
Set the scan rate to about 1/2 the scan range, e.g., if the range is set to 20
µ
m, the
scan rate would be about
10 µ
m/s
. Τ
he scan rate can be a very important
parameter in obtaining a stable signal. If the sample has high topographic
features, and a stable signal cannot be obtained by lowering the P-I-D settings,
reduce the scan rate.
If the line scan has a “sawtooth” shape, as shown in Figure 3-2, with the left slope very
steep and the right slope relatively flat, it is typically an indication that the tip is too far from
the surface, or that the P-I-D settings are too low.
Figure 3-2
“Sawtooth” Line Scan Shape
Step 8
When the P-I-D settings and set point are set properly, you will see a quiet, stable
signal, as shown in Figure 3-3.
Figure 3-3
Properly Adjusted P-I-D Settings and Set Point
When a scan begins, the line scan of the internal sensor signal will no longer be displayed.
To view the internal sensor signal, set the Signal window to S
COPE
mode, and open an
internal sensor signal window: select S
ETUP
⇒
A
CQUIRE
, and from the Data Channels list,
check the Fwd checkbox for the Internal Sensor channel (this can not be done when
scanning is in progress).
Summary of Contents for Aurora-2
Page 30: ...2 18 Figure 2 20 Reflection Tower Controls Swivel Tilt Focus Rotating mirror selector ...
Page 44: ...3 8 ...
Page 52: ...5 4 ...
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