1. The crystal should be tilted to the approximate

zone axis using the shadow technique. This greatly

simplifies tilting in polycrystalline samples.

 2. An area in the crystal that is the proper

thickness for good HOLZ line formation should be found.

 3. The sample should be in focus at the eucentric

position. These two conditions will insure that the

objective lens excitation is constant for every pattern

thus standardizing both the camera length and the

convergence angle for each pattern.

 4. The condenser aperture should be centered.

 5. The sample should be tilted to the exact zone

axis, again using the shadow image technique.

 (By iterating between 5 and 3, a good zone axis

pattern can be obtained.)

 6. The spot exposure meter should be used to

determine the proper exposure time for recording the

diffraction pattern.

 Under the above conditions, only STEM and focused

TEM probes should be used for generating the convergent

beam. If a convergent probe is formed using the

overexcited objective lens method, the sample must still

be at the eucentric position, but since the image will not

be focused, the objective lens current must be recorded

so that it may be reproduced for each subsequent pattern.