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A new miniphotometer for teaching and routine work in ore microscopy

Published online by Cambridge University Press:  05 July 2018

M. Tarkian ,
E. F. Stumpfl  and
H. Matthies
M. Tarkian
Affiliation:
Mineralogisch-Petrographisches Institut, Universität Hamburg
E. F. Stumpfl
Affiliation:
Mineralogisch-Petrographisches Institut, Universität Hamburg
H. Matthies
Affiliation:
Mineralogisch-Petrographisches Institut, Universität Hamburg
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Summary

A simple and easy-to-use miniphotometer has been designed; the expense involved amounts to only a fraction of that required for large commercially available microphotometers.

The instrument can be employed for routine investigations and for teaching reflected light microscopy in conjunction with standard reflected light microscopes.

The reflectance of grains down to 50 μm size can be measured in white and monochromatic light employing continuous band and line interference filters. The systematic error does not exceed 1.5 % of the values measured. The only aspect that distinguishes the miniphotometer from larger instruments is the limitation of spot size. A comprehensive test programme including comparative sets of measurements on a Zeiss MPM spectral microphotometer has shown that the results obtained by both instruments coincide well.

Type
Research Article
Information
Mineralogical Magazine , Volume 40 , Issue 309 , March 1975 , pp. 97 - 103
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1975

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Footnotes

1

Present address: Montanistische Hochschule, Leoben, Austria.

References

Bowie, (S. H. U.), 1957. The photoelectric measurement of reflectivity. Min. Mag. 31, 476-86.Google Scholar
Commission on Ore Mtcroscopy (International Mineralogical Association): International Tables for the Microscopic Determination of Crystalline Substances Absorbing in Visible Light. Edited by the Departamento de Cristalografia y Mineralogia, Universidad de Barcelona, August 1970.Google Scholar
Ehrenberg, (H.) and Ramdohr, (P.), 1934. Die Messung des Reflexionsvermögens mit lichtelektrischen Zellen: In Schneiderhöhn and Ramdohr, Lehrbuch der Erzmikroskopie, pp. 165-78.Google Scholar
Galopin, (R.) and Henry, (N. F. M.), 1972. Microscopic study of opaque minerals. Heifer & Sons Ltd., Cambridge, 322 pp.Google Scholar
Gavrilovic, (J.), 1970. A direct-reading, compact selenium cell reflectometer. The Microscope, 18, 3rd quarter, 215-21.Google Scholar
Moses, (J. H.), 1936. The identification of opaque minerals by their reflecting power as measured photo- electrically. Ph.D. thesis, Harvard Univ.Google Scholar
Orcel, (J.), 1927. Sur l'emploi de la pile photoélectrique pour la mesure de pouvoir réflecteur des minéraux opaques. Compt. Rend. Acad. Sci. Paris, 185, 1141.Google Scholar
Orcel, (J.), 1930. La Mesure du pouvoir réflecteur des minéraux opaques a l'aide de la cellule photoélectrique et ses applications. Bull. Soc. franç. Min. 53, 339.Google Scholar
Piller, (N.) and Gehlen (K. von), 1964. On errors of reflectivity measurements and of calculations of refractive index n and absorption coefficient k. Amer. Min. 49, 867-82.Google Scholar
Piller, (N.) and Gehlen (K. von), 1966. Colour measurements in ore microscopy. Min. Deposita, 1, 175-92.CrossRefGoogle Scholar
Tarkian, (M.), 1974. A key-diagram for the optical determination of common ore minerals. Minerals Sci. Engng. 6, 101-5.Google Scholar
Firma, Valvo, 1973. Die Fotodiode BPX 94 in einer Schaltung zur Messung sehr niedriger Bestrahlungsstärken. Valvo-Brief vom 26.3.1973.Google Scholar