Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 22 for “"X-ray tube"”.
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High temperature fracture toughness and fatigue behavior of ti-zr-mo and w-re alloys for x-ray tube application
Commercial x-ray targets for computed tomography (CT) applications consist of two major components, a metal disc made of the titanium-zirconium-molybdenum (TZM) alloy, and a surface layer in the bombarding region made of the tungsten-rhenium (W-Re) alloy. The target must endure extremely high …
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Design of x-ray source for real-time computed tomography
… To add to the current field of knowledge, two x-ray tube concepts are presented in this dissertation. First, a simulation of transient thermal analysis was performed on a compact transmission-type x-ray tube anode operating in pulse-mode. A correlation was found between deposited beam power and …
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Long range x-ray imaging utilizing coded aperture techniques and dynamic reconstruction
… and hydrogen present in these explosives, x-ray backscattering provides a viable method of collecting information about these targets by analyzing their shape. Furthermore, a coded aperture used in conjunction with dynamic reconstruction algorithms offers high sensitivity and resolution even …
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X-ray fluorescence for quantification of lead and strontium in vivo
… serve as a biomarker of long-term exposure. X-ray fluorescence has been used to measure bone Pb and Sr. However, current systems have limitations with radioisotope sources, bulky equipment, and long measurement times. A portable XRF device capable of measurement of bone Pb and Sr, overcomes the …
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Development of X-ray Coherent Scatter Projection Imaging Systems
Coherent scatter x-ray imaging systems are sensitive to material structure and chemical composition, and generate images with contrast superior to conventional transmission x-ray imaging. The goal of this thesis was to develop a scatter projection imaging system capable of acquiring images in less …
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Establishment of the Physical and Technical Prerequisites for the Determination of the Relative Biological Effectiveness of Low-energy Monochromatic X-rays
Low-energy X-rays in the range 10 - 50 keV have a wide application. One important application in radiological diagnostics is mammography, whereas, in radiotherapy, they are used for irradiation of superficial tumours, in brachytherapy and photon activation therapy. The importance of soft X-rays for …
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Pre and Post Blast Chemical Comparison of the Intra- and Inter-Variability of Metal Pipes Commonly Used in Pipe Bombs
… allowed for comparison between pipes. An x-ray tube, as an alternate excitation source, which had been added to a traditional scanning electron microscope -- energy dispersive x-ray spectrometry system was used in this research. X-ray excitation versus the electron excitation of traditional …
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Proof-of-Concept For Converging Beam Small Animal Irradiator
… the first aim of this work, a novel carbon nanotube-based compact X-ray tube optimized for</p> <p>high output and high directionality was designed and characterized. In the second aim, an</p> <p>optimization algorithm was developed to customize a collimator geometry for this unique Xray</p> …
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Capabilities and limitations of Phase Contrast Imaging techniques with X-rays and neutrons
… is all the more important since coherent X-ray and Neutron sources are mostly unavailable. We develop a model for PCI contribution to imaging for partially incoherent systems, and develop a methodology to identify a minimum and an optimum coherence length 4min and opt. We propose a …
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Development and Realization of the IGRT Inline Concept
… and its technical realization is described. An x-ray tube and a flat panel detector were installed along the treatment beam axis, such that the detector could not only be used for x-ray imaging of patients lying on the treatment couch, but also to measure the primary fluence of the therapy beam. …
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Dielectric liquid ionization chambers for detecting fast neutrons
… three liquid detectors were exposed to 250keV x-rays from an orthovoltage x-ray tube and neutrons (1.4-12MeV) from a 1-Ci 239Pu-Be source. Experimental data show that an ionization chamber filled with dielectric liquid is capable of detecting fast neutrons in pulse mode. While chamber 1, chamber …
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Detection of improvised explosive devices at long-range using coded aperture imaging of backscattered X-rays with dynamic reconstruction
… problem for the U.S. military. Current X-ray detection systems cannot detect explosives at distances above a few meters and with a source-detector system moving in relation to the target. The aim of this study is to determine the feasibility of a large-area, Coded-Aperture Imaging (CAI) …
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Xray Generation by Field Emission
Since the discovery of X-rays over a century ago the techniques applied to the engineering of X-ray sources have remained relatively unchanged. From the inception of thermionic electron sources, which, due to simplicity of fabrication, remain central to almost all X-ray applications at this time, …
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Design and analysis of low-cost x-ray imaging system incorporating consumer camera imaging
X-ray imaging is a core component of our modern medical diagnosis arsenal in combatting a broad range of disease. X-ray imaging allows medical professionals to see the internal structure and layout of the human body, and in this way allows for the visualization of unseen ailments. A current …
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From the lab to the real world : sources of error in UF6 gas enrichment monitoring
… A transmission spectrum is generated using an x-ray tube and a 'notch' filter. In this dissertation, changes that could occur in the detection efficiency and the transmission errors that could result from variations in pipe-wall thickness will be explored. Additional factors that could contribute …
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A photon counting pixel detector for x-ray imaging
… of the requirements of medical imaging on X-ray sensors is described, and the properties of film and CCDs are discussed. The work of the RD19 collaboration is introduced to show the evolution of these devices. Chapter 2 presents the basic semiconductor theory required to understand the …
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Laser-Matter Interactions at Extreme Irradiance: X-ray Generation and Relativistic Channelling
… been employed to investigate laser-produced X-rays and relativistic channelling. These lasers produce short pulses, of the order of 50 fs, with energies ranging from 1 mJ to 1 J. Thus, the peak powers reach several terawatts and with the most powerful laser system the peak irradiance exceeds …
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CONE BEAM COMPUTED TOMOGRAPHY (CBCT) DOSIMETRY: MEASUREMENTS AND MONTE CARLO SIMULATIONS
<p>Cone beam computed tomography (CBCT) is a 3D x-ray imaging technique in which the x-ray beam is transmitted to an object with wide beam geometry producing a 2D image per projection. Due to its faster image acquisition time, wide coverage length per scan, and fewer motion artifacts, the CBCT …
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Computed tomography of cats without general anesthesia: feasibility, protocol development and assessment of cats with thoracic disease
… of the VetMouseTrapTM was a transparent acrylic tube with easy access for oxygen administration at therapeutic levels with ports on both ends of the device and easy access for intravenous lines. The device is safe and met the clinical needs of cats. In phase two, CT protocols were developed and …
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