Oriental topaz

The effects of crystallographic orientation on -Ka X-ray intensity in apatite have been reported by Stormer et al. [40] under beam conditions routinely used for EMPA (15 kV, 15 nA). A different behavior was shown by topaz, analyzed in both orientations, that is, ((X)l) and (100), and fluorite in an unknown orientation. Reducing the beam current reduces the variation in intensity, but also decreases the overall intensity and thus analytical precision. 

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