Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (p. 209-222).

Intermediate-degree g-modes (those with angular order ℓ ≈ 30) were first observed in the late 1970's by Hill and Caudell (1979). However, it wasn't until 1986 that a preliminary survey was made of the 1979 differential radius observations (see Bos 1982) and a set of 4 multiplets exhibiting mode-locking was classified by Hill (1986). These multiplets with angular order ℓ ≈ 30 and eigenfrequencies of ≈350 μHz were used as a starting point for the comprehensive analysis discussed in this work. This comprehensive study culminated in the classification of a set of 20 intermediate-degree g-mode multiplets containing over 600 normal modes of oscillation. Each of these multiplets was found to contain mode-coupled sections. Of more importance, however, are the internal properties of the Sun that can be inferred from this large body of classified modes. In this work two significant consequences will be discussed. Because these modes of oscillation are localized within the inner 50% of the Sun by radius and because of their large temperature eigenfunctions implied by the observed phase-locking, these modes of oscillation provide a modification of the effective temperature profile defined for a given process in the Sun. One of these processes is the ⁸B neutrino production. The second consequence of these observations is a predicted periodic modulation of the neutrino production rates. The existence of a large set of mode-coupled gravity modes will lead to a low-frequency modulation of neutrino production rates which may account for the observed periodicity in the ⁸B neutrino production (see Haubold and Gerth 1985). The prediction of this periodicity in the neutrino production rates is unique among all the competing theories that resolve the solar neutrino paradox and is testable by the new generation of solar neutrino detectors.

The Sudbury Neutrino Observatory (SNO) was a 1 kilotonne heavy water Č{C}erenkov detector. Evidence for flavour changing neutrino oscillations was found by comparing the rate of Charged Current interactions with that of Neutral Current (NC) interactions. This thesis is concerned with the accurate determination of the NC flux in the Neutral Current Detector (NCD) phase of SNO. The measurement and understanding of radioactive backgrounds arising from decays of naturally occurring $^{232}$Th and $^{238}$U chain nuclei is crucial. This is because their daughter nuclei can produce neutrons via photodisintegration of deuterium. These would be indistinguishable from those produced by NC neutrino interactions. As the probability of neutron production was dependent upon the nature and location of activity, each contribution had to be determined separately. Of particular concern were $^{232}$Th and $^{238}$U in the D$_2$O and Neutral Current Detectors (NCDs). A maximum likelihood method was developed that exploited differences in the event isotropy and radial profile of each event class. These results were in agreement with water assay results and pre-deployment radioassays of the NCDs. An independent measurement of the $^{232}$Th content in the D$_2$O and H$_2$O was made by regularly assaying the water using filters loaded with hydrous titanium oxide. The concentration of $^{232}$Th in the water was determined by coincidence counting of the final assay sample. A new counter system was designed and built and the calibration and use of this system are presented. Two areas of increased activity were discovered on two of the NCDs deployed in the detector which would have prevented an accurate measurement of the NC flux. A method was devised to determine the composition and activity of one of these hotspots. The results were in good agreement with two independent methods and the uncertainty on the NC flux was reduced from $>7$% to $<1$%. The total number of neutrons produced per day by photodisintegration for $^{232}$Th and $^{238}$U in the D$_2$O and NCDs was measured to be $0.66^{+0.08}_{-0.07}$. This was significantly less than the expected 12.6 NC neutrino interactions per day. In the third phase, two independent data streams existed: PMT and NCD. A Monte Carlo study was undertaken to determine whether an accurate measure of the NC flux could be obtained using only PMT data. Results showed that no improvement could be made upon results from previous phases and the best measurement of the NC flux in the final phase would be made using PMT and NCD data.

The Sudbury Neutrino Observatory has previously shown that ⁸B solar neutrinos undergo flavor transformation between the Sun and the Earth. This work presents a joint analysis of one-third of the pure D₂O and salt phase data sets with an electron energy threshold of 3.5 MeV. A measurement of the neutral current interaction rate, sensitive to all neutrino flavors, gives a total ⁸B flux of 4.79 ± 0.22 (stat) ± 0.13(syst) × 10⁶ cm⁻²s⁻¹. This is in agreement with the prediction of the Standard Solar Model. For the first time we obtain the v[sunscript e] survival probability separately for downward-going (day) and upward-going (night) solar neutrinos. No significant distortion is observed day or night for ⁸B neutrinos with energies greater than 6 MeV. The lack of distortion, but overall suppression of electron neutrinos relative to the total flux, is consistent with matter-induced neutrino transformation in the Sun and the large mixing angle solution. / text

Thesis (M. Sc.)--Carleton University, 1995. / Also available in electronic format on the Internet.

Thesis (M. Sc.)--Carleton University, 1996. / Also available in electronic format on the Internet.

Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (p. 196-200).

Thesis (Ph. D.)--Carleton University, 2004. / Includes bibliographical references (p. 159-165). Also available in electronic format on the Internet.

Thesis (M. Sc.)--Carleton University, 1989. / Also available in electronic format on the Internet.

Thesis (M. Sc.)--Carleton University, 1990. / Also available in electronic format on the Internet.