Instruction manual

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 = Deflection in Contact Mode or Data type = Amplitude in
TappingMode, the data is also shifted by the setpoint.(i.e., if the Data type =
Deflection and Data Center = 0, then the setpoint is at the center of the vertical
scale.
Deflection Sensitivity
Deflection Sensitivity (B) relates the cantilever deflection signal in volts from the controller to the
actual deflection of the cantilever (in nm). It equals the inverse of the slope of the deflection versus
Z piezo position line when the tip is in contact with a very hard, stiff sample as shown in Figure
11.4c. 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 deflection
sensitivity value before deflection 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.