Department of Physics (Fredericton)

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The toroidal diffraction grating for the HiRES spectrometer: effect of potting on surface figure
The toroidal diffraction grating for the HiRES spectrometer: effect of potting on surface figure
by Jamaal Yaqzan, The high resolution stigmatic extreme ultraviolet spectroheliometer (HiRES) rocket payload employs a toroidal diffraction grating as the dispersing element in its spectrometer. Such a grating produces stigmatic images (free from astigmatism) of the sun at several different wavelengths, which are determined by the grating's geometry. For this paper, the aspect ratio of the grating was determined both before and after it was potted--a mounting procedure in which the grating element is in encased in silicon adhesive; the effect of this upon the figure of the grating being previously unknown. A change in the surface figure would mean the highest quality images for a given angle of incidence would be produced at different wavelengths than those anticipated.
The use of 111In as a probe of magnetic environments in liquids
The use of 111In as a probe of magnetic environments in liquids
by Michael Harwood, Local magnetic effects in liquids - specifically an acid solution of indium chloride and molten indium - were studied using 111In as a probe. The gyromagnetic ratio for 111Cd (5/2+) was measured to be 0.310 ± .008. This is within 0.5% of the accepted value and indicates that the accuracy of this experiment is sufficient (although the precision could be improved). The g factor of 111Cd was also measured for a molten environment. The result of 9 = 0.293 ± .011 (or 0.306 with a diamagnetic correction) overlaps the other value and indicates that any change to due Knight Shift or paramagnetic effects is less than 1% and too small to notice., 20 unnumbered pages after last numbered page
The use of a Bragg grating as a temperature sensor
The use of a Bragg grating as a temperature sensor
by David F. Matheson, A fiber Bragg grating has a periodic disturbance in the index of refraction of the core of an optical fiber. It can be used as a temperature sensor due to the change in the grating period that occurs because a thermal expansion. Fiber Bragg gratings temperature sensing system would be of great use in many applications, particularly in medical settings. The goal of this project was to construct and test a temperature sensor using a fiber Bragg grating as the sensing component. The system was successfully tested for use in the range of 30°C to 45°C. A method of isolating the grating was devised, such that it would not be exposed to environmental factors other than those desired. A measurement precision of 0.1 °C was successfully developed.
Tidal features in the upper-middle atmosphere
Tidal features in the upper-middle atmosphere
by Dave MacKenzie, Over the past thirty years there has been an increase in interest in atmospheric physics and atmospheric modelling. The Extended Canadian Middle Atmosphere Model (Extended CMAM) is one of the first models of its kind to be developed. A large focus in this development is to examine and contrast particular aspects of the modelled motions against observations from ground based stations and satellites to evaluate how well the model simulates these motions. An additional focus in this project is to suggest features which have not yet been observed and to examine the physical processes operative in the atmosphere. Analysis of the Extended CMAM output has shown the presence of tidal signatures in the mesopause region (70krn-l 40km). This paper will summarize the Extended CMAM, provide some background on atmospheric tides and present various aspects of these tidal signatures.
he Doppler broadening effects in optical bistability
he Doppler broadening effects in optical bistability
by Gregory R. J. Grondin, In this thesis, the Doppler broadening of the fluorescence spectrum of an optically bistable medium in a ring cavity will be studied. Analytical and numerical results for the input - output characteristics as well as the fluorescence spectrum of a bistable system will be presented. It will be found that the values for some parameters used in the numerical analysis are close to the experimental values found after the theoretical work was done. Also, it will be shown that the Doppler broadening has effects on the fluorescence spectrum other than pure broadening., Document is unnumbered.

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