Instruction manual
Fluid Operation
General Fluid Operation
Rev. B MultiMode SPM Instruction Manual 131
Figure 8.2f Imaging a Sample Covered by a Drop of Fluid
2. Complete the following if
starting with a sample in solution:
a. Incubate 30-40µl of your sample on the support mounted on the puck (the liquid should
form a small dome over the support). During this incubation the sample should adhere
to the support (e.g., mica).
b. Install the sample support on the AFM scanner.
c. Carefully install the fluid cell inside the head.
• Inspect from the front to make sure the fluid is well confined to the mica area only.
• Aim the laser on the cantilever and adjust the photodiode detector position (see
Section 8.2.7).
Note: Always verify that the microscope is dry and that all MultiMode surfaces are
free of spilled fluid. Wick away moisture and droplets with filter paper.
Note: Over time, evaporation of the fluid may necessitate replenishing the fluid cell
using a standard micropipette or syringe.
8.2.6 Align the Laser
Use either of the techniques for aligning the laser on the probe (see Chapter 5, Laser Alignment:
Section 5.2.) The following considerations apply:
• Refraction causes the laser beam path to bend slightly entering and exiting the fluid
surrounding an immersed probe as compared to the path in air. However, the basic
process is essentially the same.
• It may be necessary to adjust the tilt of the mirror to position the laser on the
photodetector.
• In the fluid cell, the probe rests flat on an angled, glass surface. This surface produces a
false laser reflection, even when the laser is not aimed at the probe. This reflection from
the glass surface does not affect operation of the MultiMode, but it can be a source of
confusion when aligning the laser. Ignore this faint reflection and focus on the much
brighter reflection from the cantilever.
• The Sum signal on the display monitor typically displays less than 1V when the laser is
not aligned on the probe. The Sum signal should rise well above 1V when the laser is
reflecting off the probe.
4134
Scanner
Sample
Puck
Fluid Probe Holder
Meniscus