Force Imaging
Force Calibration Control Panels and Menus
186
MultiMode SPM Instruction Manual
Rev. B
11.3.3 Channel 1, 2, 3 Panels
Data Type
This parameter allows you to select the type of data you want to display on the vertical axis.
Data Scale
This parameter sets the vertical scale in the force plot. Increasing this parameter expands the range
of the display about the centerline causing more of the force curve to fall on the graph. Initially, set
this parameter to its maximum value, then gradually reduce.
Data Center
This parameter shifts the displayed force plot in the vertical axis.
Note:
For
Data type
=
De
fl
ection
in Contact Mode or
Data type
=
Amplitude
in
TappingMode, the data is also shifted by the setpoint.(i.e., if the
Data type
=
De
fl
ection
and
Data Center
=
0
, then the setpoint is at the center of the vertical
scale.
De
fl
ection Sensitivity
De
fl
ection Sensitivity
(B) relates the cantilever de
fl
ection signal in volts from the controller to the
actual de
fl
ection of the cantilever (in nm). It equals the inverse of the slope of the de
fl
ection versus
Z piezo position line when the tip is in contact with a very hard, stiff sample as shown in
. The NanoScope system automatically calculates and enters the value from the graph once
you use the mouse to draw a line parallel to the graph. You must properly determine the de
fl
ection
sensitivity value before de
fl
ection data in nanometers can accurately display. For a proper force
curve, the line has a negative slope with typical values of 10-100 nm/V; however, by convention,
values appear as positive in the menu.
Amplitude Sensitivity (TappingMode)
Amplitude Sensitivity
relates the vibrational amplitude of the cantilever (in nm) to the amplitude
signal (in V) from the controller. To calculate the
Amplitude Sensitivity
, measure the slope of the
RMS amplitude
versus the
Z piezo position
when the tip is in contact with a very hard, stiff
sample. The NanoScope software automatically calculates and enters the value from the graph after
you use the mouse to draw a line to the graph. You must properly calibrate the
Amplitude
Sensitivity
before amplitude data can be correctly displayed in nm.
