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[en] The ZED-2 (Zero Energy Deuterium) reactor is an experimental low-power critical facility located at the Atomic Energy of Canada Limited Chalk River Laboratories in Ontario, Canada. The facility is used to perform physics experiments in support of the CANDU and Advanced CANDU Reactor (ACR) programs. The reactor core is a large cylindrical vessel in which reactor fuel rods are positioned vertically. A heavy water moderator is pumped into the vessel to make the reactor critical. The ZED-2 design is very versatile: it can accommodate mixed fuel types in a variable number of fuel rods each with or without CANDU-type or ACR-type channels; channel coolants can be light or heavy water, or air, and can vary from channel to channel; lattices can be square or hexagonal with continuously variable lattice pitch; and some CANDU-type channels can be heated. Many of the experiments performed involve uniform cores containing the same type of fuel and channel in each fuelled location. However, at times a smaller number of fuel rods and channels are placed in the centre of a larger region of reference fuel to form a critical core assembly. These are called substitution experiments. The purpose of this paper is to describe why substitution experiments are performed, detail how they have historically been conducted and analyzed to extract the desired data from the test fuel, and finally how they are performed and analyzed today using specialized software.
[en] With the start of the Large Hadron Collider (LHC) at CERN it is now possible to study physics at the TeV-scale for the first time. At this unprecedented energy range it is expected that the Standard Model of particle physics will reach its limits and new phenomena can appear. One of the main goals of the ATLAS experiment is the search for physics beyond the Standard Model. This includes observing supersymmetric particles, which are predicted to have masses of several hundred GeV up to a few TeV. The subject of this thesis is the search for supersymmetric particles in final states with jets and missing transverse energy and the evaluation of the ATLAS discovery potential for supersymmetric particles in the Minimal Supersymmetric Standard Model (MSSM) parameter space for these channels. Different centre-of-mass energies of √(s)=14 TeV, 10 TeV and 7 TeV are assumed. For many R-parity conserving SUSY models, the decay of supersymmetric particles leads to detector signatures characterized by missing transverse energy and multi-jets, sometimes accompanied by leptons. In this thesis, SUSY searches with ≥2-6 jets and 0-2 leptons (electrons, muons) are studied, with a focus on 0-lepton channels, that are expected to be sensitive in large areas of the SUSY parameter space. The search strategies for supersymmetric particles are applied on a sets of differently constrained SUSY models and on several hundred SUSY signals, generated within the pMSSM subspace of the MSSM. The goal of this work is to explore the reach of the performed SUSY searches for completely different decay signatures. It will be shown that the ATLAS SUSY searches cover a large parameter space of SUSY models. The first p-p collisions at a centre-of-mass energy of √(s)=7 TeV in March 2010 allow a comparison of the measured data with the Monte Carlo predictions, in order to see how well the detector response is understood in the context of SUSY specific variables used in the 0-lepton analyzes. All measurements are found to be in agreement with the Standard Model expectations within the associated systematic uncertainties. The results indicate that the ATLAS SUSY searches cover a large parameter space and it is possible to discover or exclude some SUSY models already with a few pb-1 of integrated luminosity.
[en] The study on the natural gas and condensate occurrence in salt, specifically in the salt stock Gorleben-Rambow covers the topics development of salt deposits, salt stocks, crude oil and natural gas, gas and condensate inclusions in evaporite. Experimental data on crude oil borehole studies in Gorleben, natural gas drill holes in the salt stock Rambow, Luechow Z1 - saltstock Wustrow, gas indications, gas occurrences and gas detection are summarized.
[en] Geant4 is a toolkit used to simulate the pass age of particles through matter. Recently, it has been used in many medical physics applications. In radiotherapy, positron emission tomography, and magnetic resonance tomography, Geant4 has been applied to accurately simulate the propagation of particles and the interaction of particles, not only with medical devices, but also with patient's phantoms.1,2 Many researchers try to use patient's image data to calculate the dose. The use of DICOM images files to simulate is desired. We construct detector with parameterized volume for Geant4 simulations, which can be applied to simulations using DICOM data as the input.We try to apply this code to the patient's DICOM images to simulate the propagation and interaction of the particles. So we can calculate the absorbed dose of the patient. In this study, the used visualization tool is called gMocren. The purpose of the present paper is to verify a volume visualization tool that simultaneously displays both the complex patient data and the simulated dose distribution with real patient's DICOM data. We applied a volume visualization tool for GEANT4 simulation. We developed to create the each voxel's dose tables of the every slices and review the distribution with DICOM file, gMocren is very convenience tool but provide only qualitative analysis. We need more enhanced functions to display contour like RTP and utility program to create dose table in every points.
[en] CdZnTe (CZT) has been studied for many years as a material for room-temperature, high energy resolution gamma-ray detectors. Currently, prototypical detectors are now available for medical imaging, industrial tomograph and astrophysics in the world-wide. For this reason and next-generation gamma-ray detector, core-technology of CZT crystal growth and detector fabrication is much more crucial. CZT crystal was grown by Low-pressure Bridgman Method at Korea Atomic Energy Research Institute (KAERI) for room-temperature gamma-ray detector. In this study, performance of a CZT radiation detector such as I-V curve and energy resolution for gamma-ray was presented. We measured the I-V curve to define the resistivity of the grown CZT crystal. The electrometer, Keithley 6517A, was used to biasthe high voltage on the detector and read the leakage current. The measured I-V curve is shown in Fig. 3. Resistivity of the planar-type CZT detector, which didn't apply any passivation, was 7.8 x 109 Ω·cm. The pulse height spectra was obtained with a CREMAT® CR-110 preamplifier, ORTEC® 572 amplifier, and 919 MCA. Figure 4 and 5 shows the pulse height spectra for 511 keV and 660 keV gamma-ray. The 10.0 % and 9.7 % energy resolutions for 511 keV and 662 keV gamma-ray, respectively, were obtained with the fabricated CZT detector. CZT single crystal was grown by low-pressure Bridgman method. Large domain of (1,1,1) crystalline face was obtained. Resistivity of 7.8 x 109 Ω·cm of the grown CZT crystal, can be fabricated gamma-ray detector from the results. 10.0 % and 9.7 % of enrgy resolution for 511 keV and 662 keV gamma-ray, respectively, was also obtained. In the future work, passivation and types of detector, such as a Schottky-type, a Frisch Collor, and a coplanar electrode, will be studied to improve energy resolution.
[en] This work was carried out aiming to design and characterise 9-12% Cr steels with tailormade microstructures for applications in fossil fuel fired power plants. The investigations concentrated in the design and characterisation of heat resistant steels for applications in high oxidising atmospheres (12% Cr) and 9% Cr alloys for components such as rotors (P91). ThermoCalc calculations showed to be a reliable tool for alloy development. The modeling also provided valuable information for the adjustment of the processing parameters (austenisation and tempering temperatures). Two 12% Cr heat resistant steels with a fine dispersion of nano precipitates were designed and produced supported by thermodynamic modeling (ThermoCalc). A detailed characterisation of the microstructure evolution at different creep times (100 MPa / 650 C / 8000 h) was carried out by scanning transmission electron microscopy (STEM). The results of the microstructure analysis were correlated with the mechanical properties in order to investigate the influence of different precipitates (especially M_2_3C_6 carbides) on the creep strength of the alloys. Precipitation of Laves phase and Z-phase was observed after several hundred hours creep time. Very few Z-phase of the type Cr(V,Ta)N nucleating from existing (V,Ta)(C,N) was observed. Both alloys show growth and coarsening of Laves phase, meanwhile the MX carbonitrides present a very slow growth and coarsening rate. Alloys containing Laves phase, MX and M_2_3C_6 precipitates show best creep properties. The influence of hot-deformation and tempering temperature on the microstructure evolution on one of the designed 12% Cr alloys was studied during short-term creep at 80-250 MPa and 650 C. Quantitative determination of dislocation density and sub-grain size in the initial microstructure and after creep was investigated by STEM combined with the high-angle annular dark-field detector (HAADF). A correlation between microstructure evolution and creep response was established. All crept samples showed a significant increase of sub-grain size and a reduction of the dislocation density. Hot deformed samples showed better creep strength than non hot-deformed samples, due to homogenisation of the microstructure. The tempering temperature affected the dislocation density and the sub-grain sizes, influencing the creep behaviour. 9% Cr alloys were designed supported by ThermoCalc. Two sets of alloys were produced: 9% Cr alloys with 0.1 % C and 0.05% C and 9% Cr alloys containing ∝ 0.03% Ti again with 0.1% C and 0.05% C (always wt%). Microstructure investigations showed good agreement with the predicted phases of the thermodynamic modeling. The volume fraction of precipitated M_2_3C_6 carbides is directly related to the carbon content of the alloys. Hardening of the Ti-containing alloys by precipitation of fine dispersed Ti-based MX particles was achieved. The precipitation of these carbides was limited to the austenisation and tempering treatment used. The microstructure evolution (sub-grain and particle size) during creep at 650 C / 100MPa was investigated by STEM-HAADF. The sub-grain size evolution and the coarsening of precipitates (MX carbonitrides, M_2_3C_6 and Laves phase) were more pronounced for Ti-containing alloys. 9Cr alloys without Ti and with low carbon content presented the highest creep strength of all investigated alloys.
[en] This paper studies the behavior of Aliquat 336 in the Molybdenum extraction from basic solutions from the process of Codelco Norte ion exchange applied at the pilot level. The results obtained in the study show that a stage is required previous conditioning of the organic phase with sulfuric acid, also show that it is required to feed the Elution Extraction stage with a content less than 1 g/L of Molybdenum to obtain greater efficiency in the extraction process of this element. From the point of view of the kinetics, in the extraction stage the equilibrium reached 30 seconds with 41.32%, while in the Re-extraction stage the balance was reached at 300 seconds with 90.59%. The Mc Cabe Thiele diagram shows that 3 stages are required to achieve extract Molybdenum from basic solutions (pH≅10) with a concentration of 1,120 mg/L up to 56 mg/L which represents an efficiency of 95%. Various re-extractants were evaluated on ammonium base, obtaining higher percentages of re-extraction with Ammonium Chloride. The diagram of Mc Cabe Thiele in the Retraction stage shows that 2 stages are required, obtaining an advance of 4 g/L from an organic loaded with 449 mg/L of Mo, with a 95% efficiency. According to the results obtained, it is possible to obtain solutions Molybdenum concentrates from basic solutions through the use of Aliquat 336. It is important to note that this is the first study carried out in these pH conditions, so this work will serve as a basis for future research in the extraction of Molybdenum from alkaline solutions