<p> An attempt was made to measure the yields of the stable cadmium isotopes produced in the thermal-neutron fission of 233U and 235U using a solid-source mass spectrometer. The results for 235U fission indicate that there is structure in the mass-yield curve for the region studied which takes the form of a depression around masses 112-114. The origin of this structure is discussed in terms of the various mechanisms which have been proposed to explain the nature of the mass distribution in the symmetric region.</p> <p> The 233U study was unsuccessful because of the experimental difficulties encountered, primarily the interference from terrestrial cadmium and the low recovery of the fission products. </p> / Thesis / Master of Science (MSc)

<p> This work was the first study at the beam port # 4 at the McMaster Nuclear Reactor, involving prompt gamma in vivo neutron activation analysis. The project consisted of experimental and computational parts. The computational part was done using MCNP program, which simulates the neutron and photon transport in the medium. The first thing assessed was the energy dependent neutron fluence rate in the collimated neutron beam, at the site. This was done in order to figure out the complete source (sdef) card for further MCNP calculations. This was combined experimental and computational work. For the experimental part, various activation foils were used and computational part was done by using MCNP programming.</p> <p> The second part of the project involved experimental prompt gamma in vivo activation analysis using 7 different phantoms, ranging from 30 mL to 2 L. Three different elements were observed. The prompt gamma in vivo detection of cadmium was the preliminary calibration study and the experiments were done with all seven phantoms. The calibration lines and MDL were assessed for all phantoms, with concentration ranging from 0 to 50 ppm. The prompt gamma in vivo detection of boron and mercury was done using 30 mL phantoms. Calibration lines and MDL for both elements were assessed as well.</p> <p> MCNP experimental simulations for 30 mL water phantoms were done and they were in close agreement with the experimental results. Furthermore, the MCNP gamma and neutron dose survey in the cave was done.</p> <p> The results obtained showed that there are numerous open possibilities for improvement in terms of in vivo prompt gamma analysis at the site. It predominantly includes the improvements in prompt gamma detection techniques and MCNP source definition. Furthermore, it was found that MCNP programming is the ideal tool for assessment and control of the experimental results in this case. It means that in the future research, the MCNP modeling will be the essential part of the in vivo prompt gamma activation analysis at this beam port.</p> / Thesis / Master of Science (MSc)

<p> With the increasing concern about pollution the need has arisen for accurate trace analysis of hazardous or toxic trace elements such as cadmium. While the modern analytical chemist has at his disposal a great many different techniques for analysis, surveys of inter-laboratory analyses have often produced serious discrepancies among results done by different methods and/or workers. The purpose of this thesis will be to review the different methods for trace analysis of cadmium in biological samples and to experimentally compare two of these, atomic-absorption spectrometry and neutron-activation analysis.</p> / Thesis / Master of Science (MSc)

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Juvenile rainbow trout were chronically exposed to cadmium in hard water, soft water, and in calcium-supplemented soft water in order to understand the effects of long term cadmium exposure in freshwater fish. A particular goal was to characterize changes in gill cadmium burden and the cadmium-binding properties of the gills during chronic sublethal exposures, so as to examine the applicability of the acute gill surface metal binding model or Biotic Ligand Model to trout chronically exposed to cadmium. Trout were exposed for 30 days to sublethal concentrations of cadmium in: a) moderately hard, Hamilton tap water (Ca = 1000 μM), b) synthetic soft water (Ca = 130 μM), or c) calcium-supplemented soft water (Ca = 260, 470, 770, and 1200 μM Ca). For both the hard and soft water cadmium exposures, no effects were observed on growth, swimming performance, and whole body ions. Growth and whole body and plasma Ca²⁺ concentrations were similar for all treatments in the calcium-supplemented soft water experiment; however, swimming performance was significantly reduced for the 470 μM Ca + Cd exposed fish. Acclimation to cadmium occurred in the hard water and lower concentrations of calcium-supplemented exposures but not in the soft water exposure. Cadmium accumulation was greatest in kidneys and gills and was directly related to cadmium exposure concentration. Tissue metal burdens were reduced with increased water calcium concentrations. Affinity of the gill for cadmium and the number of binding sites for cadmium decreased at higher water calcium concentrations. Affinity of the gill for Cd decreased with chronic cadmium exposure but binding site numbers increased with chronic Cd exposure. The acute gill binding model or Biotic Ligand Model, originally developed in soft water, was successfully applied to fish in both hard and soft water; however, complications arose when extending the model to fish chronically exposed to cadmium at various water calcium concentrations. / Thesis / Master of Science (MS)