Thesis (Ph. D.)--University of Canterbury, 2008. / Typescript (photocopy). Includes bibliographical references (p. 162-187). Also available via the World Wide Web.

Thesis ( Ph.D.). / Written for the Dept. of Physics. Title from title page of PDF (viewed 2009/06/11). Includes bibliographical references.

Thesis (Ph. D.)--University of Hong Kong, 1990.

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No description available.

by Lui Bong Chun, Richard. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references. / Abstract / Acknowledgment / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background for the Project --- p.1 / Chapter 1.1.1 --- Interests in Blue-Green Laser --- p.1 / Chapter 1.1.2 --- Progress of Blue-Green Laser --- p.2 / Chapter 1.2 --- The Aim of the Project --- p.3 / Chapter 1.3 --- Overview the Remaining Parts of this Thesis --- p.4 / Chapter 1.4 --- References --- p.6 / Chapter Chapter 2 --- Sum Frequency Generation --- p.8 / Chapter 2.1 --- Introduction --- p.8 / Chapter 2.2 --- Sum Frequency Generation --- p.8 / Chapter 2.2.1 --- Theoretical Background for Sum Frequency Generation --- p.9 / Chapter 2.2.2 --- The Coupled Wave Equations for SFG --- p.13 / Chapter 2.2.3 --- Phase Matching Considerations --- p.16 / Chapter 2.3 --- References --- p.18 / Chapter Chapter 3 --- Cerenkov Radiation --- p.19 / Chapter 3.1 --- Introduction --- p.19 / Chapter 3.2 --- The Properties of Cerenkov Radiation by Using TM Mode --- p.21 / Chapter 3.2.1 --- Refractive Index Notation --- p.23 / Chapter 3.2.2 --- Fundamental Wave TM Guides Mode --- p.23 / Chapter 3.2.3 --- Second Harmonic TM Radiation Mode --- p.24 / Chapter 3.2.4 --- Efficiency of SHG --- p.25 / Chapter 3.3 --- Simplified Model Analysis of Cerenkov Radiation in TE Mode --- p.29 / Chapter 3.4 --- Simulation --- p.33 / Chapter 3.4.1 --- Modeling the LiNb03 --- p.33 / Chapter 3.4.2 --- Modeling an Asymmetric Slab Waveguide ´ؤPMMA doped with MNA on Fused Quartz --- p.37 / Chapter 3.4.3 --- Modeling a Symmetric Slab Waveguide ´ؤPMMA doped with MNA on Fused Quartz --- p.42 / Chapter 3.5 --- References --- p.47 / Chapter Chapter 4 --- Ellipsometry --- p.49 / Chapter 4.1 --- Introduction --- p.49 / Chapter 4.2 --- General Principles --- p.49 / Chapter 4.3 --- Basic Operation --- p.50 / Chapter 4.4 --- The Optical Constants of the Bulk Materials --- p.51 / Chapter 4.5 --- Calculation the Refractive Index of the Substrates --- p.53 / Chapter 4.6 --- Ellipsometric Theory for the Thin Film --- p.57 / Chapter 4.7 --- Measurement the Refractive Index and the Thickness of the Thin Film --- p.59 / Chapter 4.7.1 --- Data --- p.62 / Chapter 4.7.2 --- Discussions --- p.73 / Chapter 4.8 --- Calculation the Refractive Index of the thin Film by Considering as a Bulk Material --- p.78 / Chapter 4.9 --- References --- p.80 / Chapter Chapter 5 --- Prism Coupling --- p.81 / Chapter 5.1 --- Introduction --- p.81 / Chapter 5.2 --- Coupling of a Plane Wave --- p.82 / Chapter 5.3 --- Numerical Approach for the Calculation of the Coupling Efficiency --- p.85 / Chapter 5.4 --- Experiment --- p.88 / Chapter 5.4.1 --- Experimental Setup --- p.88 / Chapter 5.4.2 --- Experimental Result and Discussions --- p.90 / Chapter 5.5 --- References --- p.92 / Chapter Chapter 6 --- Conclusion --- p.93 / Chapter Chapter 7 --- Future Plans --- p.96 / Chapter 7.1 --- Simplified Model of Corona Poling --- p.96 / Chapter 7.2 --- Advanced Models of Poling --- p.98 / Chapter 7.2.1 --- Slab Waveguide --- p.98 / Chapter 7.2.2 --- Channel Waveguide --- p.99 / Chapter 7.3 --- References --- p.100 / Chapter Appendix 1 --- Materials' Descriptions --- p.A-l / Chapter A.1.1 --- 2-Methyl-4-Nitoaniline --- p.A-1 / Chapter A.1.2 --- Poly ( Methyl Methacrylate ) --- p.A-3 / Chapter A.1.3 --- References --- p.A-4 / Chapter Appendix 2 --- Fabrication Procedures --- p.A-5 / Chapter A.2.1 --- Cleaning the Apparatus --- p.A-5 / Chapter A.2.2 --- Cleaning the Substrate --- p.A-5 / Chapter A.2.3 --- Thin film Fabrication --- p.A-5 / Chapter A.2.4 --- Thin Film Removal --- p.A-6 / Chapter A.2.5 --- References --- p.A-6 / Chapter Appendix 3 --- Alpha Step --- p.A-7 / Chapter A.3.1 --- Introduction --- p.A-7 / Chapter A.3.2 --- Experimental Setup --- p.A-8 / Chapter A.3.3 --- Experimental Results --- p.A-9 / Chapter A.3.3.1 --- Thin Film of PMMA without Dopant --- p.A-9 / Chapter A.3.3.2 --- Thin Film of PMMA doped with MNA --- p.A-19 / Chapter A.3.4 --- Discussions --- p.A-27 / Chapter A.3.5 --- References --- p.A-28 / Chapter Appendix 4 --- Scanning Electron Microscope --- p.A-29 / Chapter A.4.1 --- Scanning Electron Microscope --- p.A-29 / Chapter A.4.2 --- Reference --- p.A-30 / Chapter Appendix 5 --- Gaussian Beam & Coordinate System Transformation --- p.A-31 / Chapter A.5.1 --- Gaussian Beam in a Homogeneous Medium --- p.A-31 / Chapter A.5.2 --- Transformation of the Coordinate Systems --- p.A-32 / Chapter A.5.3 --- Reference --- p.A-32 / Chapter Appendix 6 --- Waist Size Measurement of Gaussian Beam --- p.A-33 / Chapter A.6.1 --- Waist Size Measurement of Gaussian Beam --- p.A-33 / Chapter A.6.2 --- References --- p.A-34 / Chapter Appendix 7 --- Quasi Phase Matching --- p.A-35 / Chapter A. 7.1 --- Introduction --- p.A-35 / Chapter A.7.2 --- Basic Concept of QPM --- p.A-36 / Chapter A.7.3 --- References --- p.A-38 / Chapter Appendix 8 --- Program Listing --- p.A-41 / Chapter A.8.1 --- Program Listing ( Chapter 3 ) --- p.A-41 / Chapter A.8.1.1 --- Program 3.1 (transcendental.m ) --- p.A-41 / Chapter A.8.1.2 --- Program 3.2 (linbo3.m) --- p.A-42 / Chapter A.8.2 --- Program Listing ( Chapter 4 ) --- p.A-45 / Chapter A.8.2.1 --- Program 4.1 ( ellipsometry.m ) --- p.A-45 / Chapter A.8.3 --- Program Listing ( Chapter 5 ) --- p.A-47 / Chapter A.8.3.1 --- Program 5.1 ( parameter.m ) --- p.A-47 / Chapter A.8.3.2 --- Program 5.2 ( coupling.m ) --- p.A-49 / Chapter A.8.3.3 --- Program 5.3 ( v_3_amp.m ) --- p.A-50 / Chapter A.8.3.4 --- Program 5.4 ( input_profile.m ) --- p.A-51

Thesis (MSc.-Res.)--University of Wollongong, 2008. / Typescript. Includes bibliographical references: leaf 66-69.

This work deals with the connection between the luminance of Cherenkov radiation in a nuclear reactor and his power. Cherenkov radiation arises when charged particle passing through the medium if their speed is higher than the phase velocity of light in that medium. In water moderated reactors, it is caused by secondary electrons produced by absorption of gamma rays. The measurement is done using the camera and software for photometric luminance measurements. Furthermore, there is mentioned the use of Cerenkov radiation detection to measure burnout of spent nuclear fuel. There are examples of usage of Cherenkov radiation detection to measure of nuclear reactors power, including an analysis of the measured results on research nuclear reactor VR -1. The measured results show increasing intensity of Cherenkov radiation with increasing reactor power, but residual detection response caused by delayed gamma radiation was observed after the rapid decrease of the reactor power. Possible use of detection luminance of Cherenkov radiation is in monitoring unforeseen increase in reactor power or in the control of used fuel.

Dans cette thèse, nous présentons la conception et l’étude de performance d’un tomographe par émission de positrons (TEP) corps entier utilisant la radiation Cherenkov avec capacité de temps-de-vol (projet PECHE). Nos résultats et les conclusions sont basés sur la simulation GATE pour la configuration du scanner suivante: cristal de fluorure de plomb attaché à un photomultiplicateur à micro-canaux. C’est un cristal de haute densité, transparent pour les photons ultraviolet, et possède la fraction photoélectrique la plus élevé de 46%. Le photomultiplicateur choisi est un détecteur de grande taille, rapide et pixélisé avec une efficacité quantique raisonnable, de 25% à une longueur d'onde de 400 nm. Grâce à ces propriétés, il est possible d’envisager un détecteur efficace de gamma de 511 keV avec une épaisseur de cristal de 10 mm (une longueur d'interaction) et donc de minimiser la longueur et dispersion des trajectoires de photons, résultant à une résolution temporelle optimisée. Nous avons étudié les configurations différentes de détecteur élémentaire tels que le cristal avec les épaisseurs de 10 et 20 mm, le diamètre de l'anneau de détection de 80 et 90 cm, diverses options de le revêtement de cristal (noir, blanc diffus et poli) et deux interfaces optiques (collage moléculaire et assemblage conventionnel avec un gel optique). Pour une configuration optimale, nous avons choisi un scanner TEP à trois anneaux avec un diamètre de l'anneau de 80 cm, cristal de 10 mm d'épaisseur, et un blindage en plomb. Le collage moléculaire donne une meilleure photo-collection comparée à configuration avec un gel optique. Nous avons estimé le potentiel du scanner envisagé en utilisant les tests recommandés par la norme NEMA NU 2-2012. En particulier, nous avons évalué le taux de comptage de bruit équivalent (NECR), la résolution spatiale, coefficients de recouvrement de contraste de l'image et la variabilité de bruit de fond pour le fantôme de qualité d’image. La reconstruction des images est faite en utilisant l'algorithme itératif temps-de-vol implémenté dans la plate-forme de reconstruction « open source » CASToR récemment développée. Nous avons conclu qu’un scanner corps entier utilisant la lumière Cherenkov pourrait atteindre des performances comparables à celles d'un tomographe classique à scintillation grâce à son excellente résolution temps-de-vol. L'utilisation du rayonnement Cherenkov permet d'atteindre une résolution en temps-de-vol encore meilleure. Il est limité actuellement par la dispersion de temps de transit des photomultiplicateurs existants, un faible nombre de photons optiques détectés et une efficacité de collecte de photons dans un cristal limitée. Les limitations physiques identifiées dans cette étude seront abordées dans le développement du futur photodétecteur amélioré utilisant le radiateur PbWO₄, qui permet de concevoir un scanner TEP corps entier avec une excellente performance temps-de-vols. / In this thesis we present the conception and performance studies of the foreseen Cherenkov whole-body positron emission scanner with time-of-flight potential (PECHE project). Our results and conclusions are based on the GATE simulation for following scanner configurations: lead fluoride crystal coupled with micro-channel-plate photomultiplier. This crystal is characterized by high density, transparency for photons in ultraviolet region, and one of the highest photoelectric fraction of about 46%. The chosen photomultiplier is fast, pixelized detector of a large size with a reasonable quantum efficiency, of 25% for 400 nm photon wavelength. Due to these properties, it is possible to create an efficient 511-keV gamma detector with a crystal thickness of the order of 10 mm(one interaction length) and hence minimize the length and dispersion of the photon trajectories, leading to better time resolution. We considered different configurations of the elementary detectors such as crystal thicknesses of 10 and 20 mm, the detector ring diameter of 80 and 90 cm, various options of the crystal coating (black, diffuse white and polished) and two optical interfaces (molecular bonding and conventional assembling with an optical gel). As an optimal configuration we chose a three-ring pet scanner with diameter of the ring 80 cm, 10 mm-thick crystal, protected with lead shielding. Molecular bonding gives better photo-collection if compare with configuration with optical gel. We estimated the potential of the foreseen scanner following the prescription of the NEMA NU 2-2012 standard. In particular, we evaluated the noise equivalent count rate (NECR), spatial resolution, image contrast recovery coefficients versus background variability for the NEMA image quality phantom. Reconstruction of images is done using iterative TOF algorithm implemented in the recently developed open source reconstruction platform CASToR. We concluded that due to an excellent TOF resolution a crystal-based Cherenkov whole-body scanner could achieve performances comparable with a conventional, scintillation-based tomograph. The use of the Cherenkov radiation allows to achieve even much better TOF resolution, but currently it is limited by the transit time spread of the existing photomultipliers, a low number of the detected optical photons, and a limited photon collection efficiency in a crystal. Limitations identified in this study will be addressed in the future development of the improved photodetector using the PbWO₄ radiator, which allows to conceive a whole-body PET scanner with an excellent TOF performance.

<p> Nuclear waste management and nonproliferation are among the critical tasks to be addressed for the advancement of nuclear energy in the United States. In this regard, monitoring spent nuclear fuel (SNF) and special nuclear materials (SNM) is important to continue reliable stewardship of SNF management and prevent SNM proliferation. Cosmic ray muons have been used for imaging large and dense objects, e.g., SNF dry casks, the Fukushima Daiichi unit-1 reactor, and the great pyramid of Giza. Despite their potential and success, the wide application of cosmic ray muons is limited by the naturally low intensity at sea level, approximately 10⁴ m^-2min^-1. For example, when imaging large objects, time consuming measurements typically in the order of several days or even weeks, are frequently needed to collect a statistically significant amount of muon samples to reconstruct images using muon tomography. However, when scanning time is of essence, e.g., treaty verification, low resolution imaging can result in potentially undetected diversion of nuclear materials.</p> <p>To maximize the utilizability of cosmic ray muons in engineering and physics applications, two important quantities–scattering angle and momentum–must be measured. Although many studies have demonstrated that there are significant benefits when measuring momentum in muon applications, measuring both the muon scattering angle and muon momentum in the field remains a challenge. To fill this critical gap, a novel concept using multi-layer pressurized gas Cherenkov radiators that is fieldable to allow muon momentum measurement in the field is presented in this dissertation. The proposed Cherenkov muon spectrometer is: (i) accurate (~90%) in classifying muon momentum, (ii) lightweight (< 10 kg) for easy transport and deployment in the field, (iii) compact (< 1 m³), and (iv) easily coupled with existing muon tomographic systems. Although muon momentum measurement resolution of spectrometers used in high energy physics laboratories, such as CMS or ATLAS of LHC at CERN, is less than 5% for low energy muons, these spectrometers typically (i) use bulky and large solenoidal or toroidal magnets and (ii) interfere with muon trajectories to measure momentum. These characteristics make them unsuitable for field deployment.</p> <p>In this work, the feasibility of using the proposed Cherenkov muon spectrometer coupled with current muon tomographic systems is explored and evaluated using Monte Carlo simulations and reconstruction algorithms. It is shown the use of the proposed Cherenkov muon spectrometer has the potential to improve muon tomographic imaging resolution or reduce measurement time by a factor of 10 or more when used to identify a missing fuel assembly from a SNF dry cask. In addition, a new imaging algorithm is developed that integrates muon momentum and muon scattering without significantly increasing computational cost. Advances in momentum-integrated muon tomography have the potential to improve monitoring and imaging efficiency in various nuclear engineering applications. For example, it can expand current capabilities to continue reliable stewardship in nuclear material management, i.e., Continuity of Knowledge, and prevent SNM proliferation to unauthorized states and parties. The benefit of such an approach is a compact, lightweight, and portable spectrometer that can be deployed in the field to improve existing or explore new engineering applications: muon tomography, geological studies, and cosmic radiation measurement in space.</p>