Aurora-2 User’s Manual
C H A P T E R
Chapter 4
Taking an NSOM Scan
Before following this NSOM scanning procedure, the Aurora-2 should be set up as
described in Chapter 2, and you should have taken a topography scan following the
procedure in Chapter 3. In order to take an NSOM scan, it is important to attain some pro-
ficiency in taking topographic scans.
CAUTION
The Photomultiplier Tube (PMT) can be damaged by repeated exposure
to high light levels with the voltage supplied to the tube. More importantly, repeated expo-
sure will degrade the PMT’s sensitivity over time, resulting in degraded performance. It is
a good practice to protect the PMT from high light levels, which helps ensure long detector
lifetime. When concluding an NSOM session, wait 10-15 seconds before exposing the PMT
to light. In general, whenever the voltage is supplied to the tube, the PMT should be in a
dark environment.
C
HECKING
F
EEDBACK
P
ARAMETERS
These parameters should still be set correctly from the topographic scan. However, as the
tip heats and expands, some adjustments might have to be made to the P-I-D settings. Also,
it is a good idea to recheck the tuning fork resonance frequency. Following the guidelines
in Chapter 3, adjust the P-I-D settings for the best signal. Recheck these settings immedi-
ately before beginning the scan.
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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