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No description available.

No description available.

No description available.

The aim of this work was to determine the solubility of radionuclides in solutions of cellulose degradation products (CDP) and isosaccharinic acid (ISA) the main product of cellulose degradation. Thorium was the main radionuclide investigated as the solubility of tetravalent actinides in the near field of a nuclear waste repository at high pH and low Eh has been shown to increase in the presence of such ligands. The measurement of thorium solubility was achieved by using different methods e.g. liquid scintillation counting, gamma spectrometry, ICP-MS and ICP-OES. ICP-OES was shown to be the most accurate method for this analysis. Various methods have been used to obtain solubility values e.g. undersaturation and oversaturation, and these have been investigated to determine whether the values obtained from these methods differ. Solubility studies were carried out at different pHs (6, 8 and 12). The kinetics of the complexation of thorium with ISA and with CDP were investigated at these pHs. The concentration of ISA in a solution of synthesised 10% CDP was approximately 0.01 mol dm⁻³ . In high pH solutions, the solubility of thorium was found to be 31 times greater in a solution of CDP compared to a solution of ISA at the same ISA concentration. No significant differences in thorium solubilities were found in similar solutions at pH 6 and 8. The solubilities of cobalt, nickel and cadmium were measured in the presence of 10% CDP and an equivalent concentration of ISA. The solubilities of all the metals studied in a CDP solution increased when compared to solubilities in ISA. These findings suggest that there are other complexing ligands present in the CDP other than ISA. The CDP mixture was investigated by LC-ICP-MS to determine what other complexing agents were increasing the metal's solubility.

This study, performed on simulated data, describes an untagged analysis of the Bd -> J/ѰK Ø* decay with the ATLAS detector during the low luminosity running period. This includes an analysis of the implementation and effect of different trigger strategies. One such trigger strategy uses a lifetime cut at the trigger level. It also describes the analysis of the Bd -> J/ѰK Ø* decay and its use in early studies of detector alignment. The Bd -> J/ѰK Ø* decay can be used to extract Øs, the weak mixing angle as well as the decay width difference ΔΓ. It is shown that it will be possible to make a measurement of ΔΓ with an integrated luminosity of just 200pb-1. The precision with which Øs can be measured is also calculated for different integrated luminosities ranging from 10-30fb-1.

A measurement of the branching fraction and photon energy spectrum for the decay B --> Xsγ using data from the BABAR experiment is presented. The data sample corresponds to an integrated luminosity of 210 fb⁻¹ , from which approximately 680000 BB events are tagged by a fully reconstructed hadronic decay of one of the B mesons. In the decay of the second B meson, an isolated high-energy photon is identified. The full reconstruction of one of the B mesons allows for an inclusive measurement of the photon energy spectrum in the B rest frame. A branching fraction of B(B --> Xsγ) = (3.66 ± O.85stat ± O.60sysd x 10-4) was measured for photon energies Er above 1.9 GeV. From the measured spectrum the first and second moments for different minimum photon energies are calculated, which are used to extract the heavy quark parameters mb and μ ²/π. In addition, measurements of the direct GP asymmetry and the isospin asymmetry are presented.

The accumulation of Naturally Occurring Radioactive Materials (NORM) in the scales formed on different production facilities is a well known problem in the oil and gas industry. In the year 1998, NORM was identified to be an issue in some Libyan land based oil fields. The naturally occuring radioactive materials (NORM) involved in this matter are radium isotopes (226Ra and 228Ra) and their decay products, precipitating into scales formed on the surfaces of production equipment. A field trip to a number of onshore Libyan oil fields has indicated tile existence of elevated levels of specific activity in a number of locations in some of the more mature oil fields. In this study, oil scale samples collected from different parts of Libya have been characterized using gamma spectroscopy through use of a well shielded HPGe spectrometer. In accordance with safe working practices at the University of Surrey to avoid potential alpha-bearing dust inhalation, the samples, contained in plastic bags and existing in different geometries, are not permitted to be processed. MCNPX, a Monte Carlo simulation code, is being used to simulate the spectrometer and the scale samples in order to obtain the system's absolute efficiency and then to calculate sample specific activities. The samples are assumed to have uniform densities and homogeneously distributed activity. Present results are compared to two extreme situations that were assumed in a previous study: (i) with the entire activity concentrated at a point on the sample surface proximal to the detector, simulating a worst-case scenario, and; (ii) with the entire activity concentrated at a point on the sample surface distal to the detector, simulating the most optimistic-case scenario.

The structure of the doubly-odd180 Re nucleus has been studied by means of in-beam gamma-ray spectroscopy at the Australian National University. Excited states in 180 Re have been populated using the fusion-evaporation reaction 174Yb(11B,5n) at a bombarding energy of 71 MeV. Gamma-rays have been observed by using the CAESAR detector array which consists of six Hyper-Pure Germanium (HPGe) detector and two Low Energy Photon Spectrometers (LEPS). The level scheme of 180 Re was established from the analysis of gamma-gamma coincidence relations, Directional Correlations of gamma-rays from Oriented states (DCO), electron conversion measurements and gamma-ray intensity balances. Energy levels of intrinsic states have been compared with calculations based on the Blocked BCS (BBCS) theory as well as Potential Energy Surface (PES) calculations which were also used to determine the nuclear shape. Previously identified bands have been observed in this work. Their band-head spins, however, have been reassigned. Their assignment was done on the basis of the BBCS calculations, g-factors, and potential energy surface calculations. Two high-K rotational bands have also been observed, together with a new isomer, with a mean-life of 13?s. This isomeric level was assigned a Kpi=21- band head. It has one of the new rotational bands associated with it and the second one feeding into it. This second band was tentatively assigned a Kpi=22+ configuration. Both the configurations of these bands involve the 9/2+[624] and 7/2- [514] Nilsson states which are coupled to the same protons, 5/2+[402]9/2-[514]7/2+[404] respectively, with only the third neutron, 5/2-[512] for Kpi=21- and 7/2+[633] for Kpi=22+, differing. The experimental aligned angular momenta for these bands increase as the spin increases. Prom this increase it is concluded that these high-K bands gradually change their structure from deformation aligned to rotation aligned through the Fermi aligned scheme as spin increases. During the change of the structure, the quasiparticles which form high-K states at the band heads change their direction of angular momentum from the symmetry axis to the rotation axis due to the effect of the Coriolis force. A number of K-forbidden transitions have been found in this work. Their decay can take place due to K-mixing. Statistical level mixing for Kpi=13+ and Kpi=21- isomeric states was employed in this work to explain the K-mixing process. 180Re is the highest-Z, deformed odd-odd nucleus that has been found to have a six-quasiparticle isomer; K remains approximately a good quantum number despite a tendency towards axially asymmetric shape distortions.

The use of cosmogenic beryllium-7 (7Be) as a soil and sediment tracer relies upon a number of important assumptions which to date have not been fully underpinned by supporting data. As a catchment management tool 7Be offers unique potential to assess the effects of recent land use or climate change but further research is required to provide confidence in key data and elucidate sources of uncertainty. Through a range of laboratory and field studies, this thesis aims to explore knowledge gaps relating to i) the temporal and spatial dynamics of 7Be activity in rainfall which has importance in the context of estimating fallout input during erosion studies ii) adsorption behaviour in soils which is of critical importance when considering tracer stability at the field and catchment-scale and iii) the reliability of erosion estimates using 7Be inventories at the slope-scale to address the current lack of model validation. Findings showed temporal and spatial variability of 7Be fallout emphasising the need for regular site-specific sampling to determine fallout flux during erosion studies. Data supported the assumption of rapid tracer adsorption upon fallout although highlighted the potential for 7Be mobility under changing environmental parameters, thus, raising questions with regard to tracer stability at the catchment-scale. Field investigations demonstrated the potential for current models to overestimate erosion rates by failing to accurately represent key model components, namely, 7Be depth distributions, particle size enrichment and fallout input dynamics. Where these factors cannot be determined directly, a range of erosion estimates should be given based upon realistic sensitivity analysis of model components. In this manner, reported uncertainties will reflect field processes rather than propagated analytical uncertainty alone.