An electron microprobe equipped with a device for making luminescence measurements has been used to determine the concentration of luminescence activators in zoned cassiterites of hydrothermal origin. Micron-scale growth zones contain variable amounts of Ti, Fe, W and other impurities. The impurity ions replace Sn⁴⁺ to produce luminescence centers. The relative intensity of cathodoluminescence and the amount and kind of impurity activators were simultaneously measured while scanning the growth zones with a micro-focussed electron beam.
Two distinct emission bands were observed, a yellow-green (λ ~ 565 mµ) band for Ti-activation and a blue (λ ~ 440 mµ) band for W-activation. Measurements made on a heated sample show strong thermal quenching of the Ti-activated cathodoluminescence. The decay time for the Ti-activated emission, which is independent of temperature from 21°c to 275°C, is 0.168 msec. The cathodoluminescence spectrum for W-activation closely resembles that of self-activated CaWO₄ (Leverenz, 1946) although a higher oxygen coordination (VI) for W in cassiterite is to be expected, Fe occurring with Ti appears to enhance the Ti-activated emission. Fe occurring with W or Si quenches luminescence. / Master of Science
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/64582 |
| Date | January 1968 |
| Creators | Hall, Monte Ross |
| Contributors | Geological Sciences |
| Publisher | Virginia Polytechnic Institute |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | en_US |
| Detected Language | English |
| Type | Thesis, Text |
| Format | 78 leaves, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 6754235 |
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