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When trying to find the resonance peak of a new probe, it is advised to set the lower
and upper frequencies to the boundaries of the frequency of the probe itself, which
should be located on the probe box. The selected frequency should fall just to the left
of the resonance peak and on the steepest part of the slope of the phase curve, owing
to attractive and repulsive forces at work on the cantilever's oscillation.
3.
Start and Stop: These buttons can be used to start and stop frequency sweeps.
4.
Demod Gain: This function adjusts the gain used when driving the tickler piezo. 4dB
is a good starting value for a reference sample, but should be altered in conjunction
with the drive amplitude with different probes/samples to maintain a resonance peak
under 2.5V.
3.2.1.5 Manual Z Motor Control
The Z motor, which raises and lowers the light lever, is activated with this window. The speed
of this motion can be controlled with the speed slider. When the Up and Down buttons are
held down the motor slews. The motor is jogged by touching the Up and Down buttons. The
jog size can also be controlled. The E-Stop button is the emergency stop function, and can
be accessed via the Esc button.
CAUTION: Always visually monitor the position of the Z motor. The Z motor
can drive the cantilever into the sample stage and damage both the probe
holder and the scanner.
3.2.1.6 Range Check
The usable range of the piezoelectric scanner is measured with
the Range Check option. When started, the scanner is moved in a
square pattern, which can be readily observed with the video opti-
cal microscope. This function must be completed before beginning
a scan.
Section 3-4
V 1.1 / LS-AFM Users Guide
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