An electron microprobe study of luminescence centers in cassiterite
| dc.contributor.author | Hall, Monte Ross | en |
| dc.contributor.department | Geological Sciences | en |
| dc.date.accessioned | 2016-02-01T14:44:56Z | en |
| dc.date.available | 2016-02-01T14:44:56Z | en |
| dc.date.issued | 1968 | en |
| dc.description.abstract | 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. | en |
| dc.description.degree | Master of Science | en |
| dc.format.extent | 78 leaves | en |
| dc.format.mimetype | application/pdf | en |
| dc.identifier.uri | http://hdl.handle.net/10919/64582 | en |
| dc.language.iso | en_US | en |
| dc.publisher | Virginia Polytechnic Institute | en |
| dc.relation.isformatof | OCLC# 6754235 | en |
| dc.rights | In Copyright | en |
| dc.rights.uri | http://rightsstatements.org/vocab/InC/1.0/ | en |
| dc.subject.lcc | LD5655.V855 1968.H335 | en |
| dc.subject.lcsh | Cassiterite | en |
| dc.subject.lcsh | Luminescence | en |
| dc.title | An electron microprobe study of luminescence centers in cassiterite | en |
| dc.type | Thesis | en |
| dc.type.dcmitype | Text | en |
| thesis.degree.discipline | Geological Sciences | en |
| thesis.degree.grantor | Virginia Polytechnic Institute | en |
| thesis.degree.level | masters | en |
| thesis.degree.name | Master of Science | en |
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