Scanning Electron Microscopy and X-Ray Microanalysis

109 6

effects can be minimized by selecting the initial (low) tilt

value to correspond to a well-defined detent position if

the mechanical stage is so designed, such as a physical

stop at 0° tilt. With a properly maintained mechanical

stage, the uncertainty in the tilt angle difference Δθ is

estimated to be approximately 2 % for Δθ = 50 , with the

relative uncertainty increasing for smaller values of Δθ.

4. Considering all of these sources of uncertainty, the
   measurement should be assigned an overall uncertainty
   of ±5 % relative.

a

b

. Fig. 6.20 a Stereo pair of a
machined screw thread—SEM/E–
T(positive) images; E 0 = 20 keV. b
Stereo pair with superimposed
axes for measurement of coordi-
nates needed for quantitative ste-
reomicroscopy calculations

6.5 · Making Measurements on Surfaces With Arbitrary Topography: Stereomicroscopy