A new technique has been devised to obtain time-resolved measurements of small spectral line shifts. Two linear neutral density wedges with opposite transmission gradients were placed over the top and bottom of a monochromator exit slit in such a way that a wavelength shift of a spectral line resulted in a change in light intensity transmitted through the wedges, which was monitored by two photomultipliers. To test this technique, an N II line, for which Griem has calculated the Stark shift as a function of electron density, was observed in the emission spectrum of a small theta-pinch using a monochromator of 10 Å/mm inverse dispersion. Space and time resolved line shift measurements were made and were associated with the axial velocity and the electron density fluctuations of the plasma.
An uncertainty of 0.015 Å was estimated, which, for the 1.5 Å line used, corresponds to a shift to width ratio of 10⁻², believed to be lower than any previous shift measuring technique.
Time of flight velocity measurements and conservation of mass considerations have confirmed the results as both reasonable and self-consistent. / Science, Faculty of / Physics and Astronomy, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/36556 |
| Date | January 1967 |
| Creators | Potter, Michael Urwin |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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