The purpose of this paper is to study the possible excited states in the nucleus of Cs133. At North Texas State College a 100-Kev Cockcroft-Walton accelerator has been constructed for use as a neutron source for exciting various nuclei and for studying the gamma spectra obtained to determine their energy levels.

This paper is concerned with the design, testing and performance of a coincidence system, the proposed North Texas State College accelerator.

<p> This thesis is divided into two parts, the first part being devoted to the application of Neutron Capture Gamma Ray Analysis in determining S/Si and Fe/Si ratios in Allende meteorite and lunar samples and the second part, to evidence for a possible iron isotopic anomaly in the Allende meteorite obtained by the same method. The samples were irradiated in an in-core irradiation system in the McMaster swimming-pool nuclear reactor and the collimated beam of gamma rays was detected by a pair-spectrometer consisting of a Ge(Li) detector and NaI annulus. In the first part, besides the mainstream of the work, the basic principles of Neutron Capture Gamma Ray Analysis and Neutron Activation Analysis and the supremacy of the former over the latter for this particular problem has been discussed. In the second part, along with the implications and evidence of isotopic variations of other elements in the Allende meteorite, a brief description of the classification, structure and mineralogy of the Allende meteorite is given. The success and advantage of the method along with its limitations and further directions along these lines are also discussed.</p> / Thesis / Master of Science (MSc)

<p> The decay of 3.5 minute 89Kr to levels in 89Rb has been investigated with small and large volume Ge(Li) detectors used singly and in coincidence. A total of 160 gamma rays have been attributed to the nuclear process, 120 of which have been incorporated into a proposed decay scheme.</p> / Thesis / Master of Science (MSc)

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This work aims to contribute to the study of the origins of cosmic rays, and broadly, to the advancement of both data analysis methods and instrumentation for very-high-energy γ-ray astronomy. First, reviewing the state of γ-ray astronomy, we show how gains in sensitivity can be achieved through sophisticated data analyses and improved instrumental designs. We then develop such an improved analysis method for the Very Energetic Radiation Imaging Telescope Array System (VERITAS) by combining Image Template Method (ITM) with Boosted Decision Trees (BDT), and study its performance, attaining a 30-50% improvement in integral sensitivity over the instrument’s standard analysis. Systematic issues in spectral reconstruction that the analysis displays are resolved satisfactorily by imposing a more stringent condition on the selection of its energy threshold. We employ the newly developed analysis to measure the γ-ray energy spectrum of the starburst galaxy M82, and combining our result with a measurement from the Fermi Large Area Telescope (Fermi-LAT), we find that a single power law fits the spectrum well between 100 GeV and 10 TeV, with no evidence for a spectral break or a cutoff. We conclude that this is in line with the current understanding that M82 is not a good proton calorimeter. Finally, we detail the design, implementation, and performance of the optical alignment system of the prototypeSchwarzschild-Couder Telescope (pSCT) for the Cherenkov Telescope Array (CTA), a novel two-mirror design that addresses many shortcomings of current instruments.