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Proceedings Paper • Open Access

Adam Hilger revisited: a museum instrument as a modern teaching tool
Author(s): M. João Carvalhal; Manuel B. Marques

Paper Abstract

Spectroscopy can be historically traced down to the study of the dispersion of light by a glass prism. In the early 19th century, inspired by Newton’s experiment, Fraunhofer creates a device where an illuminated slit and a lens are placed before the prism; such a device is later transformed, by Kirchoff and Bunsen, into a much handier and more precise observation and measurement instrument, the spectroscope.

In the 1930’s, the Physics Laboratory of the Faculty of Science of the University of Porto would buy, from Adam Hilger, Ltd., London, a constant deviation spectrometer. The ultimate purpose was to set up a spectroscopy laboratory for teaching and research. This model’s robust construction (the telescope and the collimator are rigidly fixed) makes it adequate for student’s practice.

To sweep across the spectrum, all it takes is to rotate the high quality, constant deviation prism – known as Pellin‐Broca prism. Spectra in the 390‐900 nm interval are observed, either directly, or through photographic recording, or even by using a thermopile and associated galvanometer, when working in the infra‐red range. The wavelength of the line under observation is read straight on a drum, which is fixed to the prism’s rotation mechanism.

Details of the construction and operation of this spectrometer are explored, against the background of present day spectrometers, automatic and computerized, thereby offering a deeper understanding of spectroscopic analysis: for instance, the use of the raies ultimes powder, a mixture of 50 chemical elements whose emission spectra provide a way of calibrating the instrument.

Paper Details

Date Published: 8 October 2015
PDF: 13 pages
Proc. SPIE 9793, Education and Training in Optics and Photonics: ETOP 2015, 979328 (8 October 2015); doi: 10.1117/12.2223202
Show Author Affiliations
M. João Carvalhal, Univ. do Porto (Portugal)
Manuel B. Marques, Univ. do Porto (Portugal)
INESC TEC (Portugal)

Published in SPIE Proceedings Vol. 9793:
Education and Training in Optics and Photonics: ETOP 2015

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