<p>This thesis comprises two parts. In the first part an overview is given of the Standard Model, Supersymmetry and R-hadrons. R-hadrons are predicted within the framework of the Split-SUSY theory, in which the gluino can have a sufficiently long lifetime to hadronise into so-called R-hadrons. These will then propagate through the ATLAS detector as (meta)stable particles. The R-hadrons, which interact strongly, have the property of changing electric charge in interactions as they move through matter. In this thesis a strategy to search for R-hadrons with the ATLAS detcector is developed.</p><p>The second part describes the ATLAS detector and the developement of the digitizer system of the ATLAS hadronic calorimeter. The digitizer system is the digitial readout system, in which data is read out from the detector to data buffers via an optical link. In the LHC environment, the operation of radiation-hard circuitry is essential. Therefore a quality control program was used to control that the design conforms to the requirements of radiation tolerance. An important part of the work was to test the devices to study their functionality and properties. This work is described in this thesis.</p>

Thesis (Ph. D.)--Oregon State University, 1973. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1981. / Typescript (photocopy). Includes bibliographical references (leaves 57-60). Also available on the World Wide Web.

Ce travail consiste en l'étude des événements diffractifs avec production de jets pour lesquels le proton diffusé est détecté dans le spectromètre à protons, VFPS, au sein de l'expérience H1 auprès du collisionneur HERA. L'objectif est de mesurer la section efficace de ce processus et de la confronter aux prédictions théoriques de la Chromo Dynamique Quantique (QCD). Ces prédictions reposent sur le théorème de factorisation collinéaire, via l'universalité des densités de partons (PDF). Les analyses précédentes de la Collaboration H1 ont montré un bon accord entre les données et les prédictions dans le domaine de l'électro-production supportant la factorisation. Cependant, en photo-production, une brisure de la factorisation a été observée. Dans ce travail, le nouveau spectromètre à protons VFPS a été utilisé afin de détecter le proton diffusé lors de l'interaction diffractive, permettant de supprimer le bruit de fond dominant dans les mesures précédentes et de réduire d'autres sources d'incertitudes expérimentales. La section efficace de production de jets dans le domaine de l'électro-production est extraite et comparée aux prédictions QCD au NLO. Ces prédictions sont basées sur les fonctions de distribution de partons (PDF) extraites des mesures antérieures par la Collaboration H1. Les sections efficaces obtenues dans ce travail sont en accord tant d'un point de la normalisation que de celui de la dépendance en les différentes variables cinématiques avec les prédictions théoriques. Nous pouvons en conclure l'universalité des PDF telle que prédite par le théorème de factorisation. De plus, l'analyse des sections efficaces différentielles permet de montrer que les prédictions basées sur des PDF extraites à partir d'une combinaison de mesures en diffraction inclusive et de production de jets semble être favorisée. La production de jets en diffraction dans le domaine de la photo-production est également étudiée dans cette thèse. On y traite de la mise en place d'un nouveau sous-déclencheur permettant de sauvegarder les données sur banques. Les données en photo-production ont été comparées aux données simulées par un programme par Monte Carlo. Le bon accord entre les deux échantillons permet de s'assurer que les différents effets détecteurs ont été correctement pris en compte et montre que la mesure de la section efficace est faisable.

There is by now compelling evidence that most of the matter in the Universe is in the form of dark matter, a form of matter quite different from the matter we experience in every day life. The gravitational effects of this dark matter have been observed in many different ways but its true nature is still unknown. In most models, dark matter particles can annihilate with each other into standard model particles; the direct or indirect observation of such annihilation products could give important clues for the dark matter puzzle. For signals from dark matter annihilations to be detectable, typically high dark matter densities are required. Massive objects, such as stars, can increase the local dark matter density both via scattering off nucleons and by pulling in dark matter gravitationally as a star forms. Annihilations within this kind of dark matter population gravitationally bound to a star, like the Sun, give rise to a gamma ray flux. For a star which has a planetary system, dark matter can become gravitationally bound also through gravitational interactions with the planets. The interplay between the different dark matter populations in the solar system is analyzed, shedding new light on dark matter annihilations inside celestial bodies and improving the predicted experimental reach. Dark matter annihilations inside a star would also deposit energy in the star which, if abundant enough, could alter the stellar evolution. This is investigated for the very first stars in the Universe. Finally, there is a possibility for abundant small scale dark matter overdensities to have formed in the early Universe. Prospects of detecting gamma rays from such minihalos, which have survived until the present day, are discussed. / Kosmologiska observationer har visat att större delen av materian i universum består av mörk materia, en form av materia med helt andra egenskaper än den vi upplever i vardagslivet. Effekterna av denna mörka materia har observerats gravitationellt på många olika sätt men vad den egentligen består av är fortfarande okänt. I de flesta modeller kan mörk materia-partiklar annihilera med varandra till standardmodellpartiklar. Att direkt eller indirekt observera sådana annihilationsprodukter kan ge viktiga ledtrådar om vad den mörka materian består av. För att kunna detektera sådana signaler fordras typiskt höga densiteter av mörk materia. Stjärnor kan lokalt öka densiteten av mörk materia, både via spridning mot atomkärnor i stjärnan och genom den ökande gravitationskraften i samband med att en stjärna föds. Annihilationer inom en sådan mörk materia-population gravitationellt bunden till en stjärna, till exempel solen, ger upphov till ett flöde av gammastrålning, som beräknas. För en stjärna som har ett planetsystem kan mörk materia även bli infångad genom gravitationell växelverkan med planeterna. Samspelet mellan de två mörk materia-populationerna i solsystemet analyseras, vilket ger nya insikter om mörk materia-annihilationer inuti himlakroppar och förbättrar de experimentella möjligheterna att detektera dem. Mörk materia-annihilationer inuti en stjärna utgör också en extra energikälla för stjärnan, vilket kan påverka stjärnans utveckling om mörk materia-densiteten blir tillräckligt stor. Denna effekt undersöks för de allra första stjärnorna i universum. Slutligen finns det också en möjlighet att det i det tidiga universum skapades mörk materia-ansamlingar som fortfarande finns kvar idag. Utsikterna att upptäcka dessa genom mätning av gammastrålning diskuteras. / QC 20120130

This thesis describes several calibrations of the Time-of-Flight (TOF) detector at the Solenoidal Tracker at RHIC (STAR). These calibrations are required to allow Particle Identification (PID) which benefits many physics analysis. These calibrations treat the Integral Non-Linearity (INL) of the time to digital converters, the global offsets, the slewing from pulse time dependence on the pulse height, and the transmission times inside the detectors. Each of these corrections will be described. The data for the INL correction was collected at Rice University using two different electronics configurations. Care was taken to insure the two approaches were consistent. These calibrations were tested using "cable-delay tests." Data from RHIC Run 9 200 GeV data will be used to confirm the effectiveness of the INL, offset, slewing, and transmission time calibrations.

With the development of mechanical fault diagnosis technology, complex mechanical systems do not need to be shut down periodically for the maintenance. The working condition of the mechanical systems can be monitored by analyzing the wear metal particles in the systems' lubricating oil. However, the output signals of the monitoring sensor are non-stationary. In some case the particle signals are overlapped with each other. The goal of this thesis is to find a method to decompose those overlapped particle signals, and then count the particle number in the lubricating oil. At the beginning EMD method was introduced in the experiment because of the character of the sensor signals. In this project, because EMD method is sensitive to the noise in the original signals, an improved version of EMD, EEMD method was implemented. Finally, a post processing method was used to get a better result.

Production of protein and semi-conductor crystals with advanced quality and properties is considered to be possible under microgravity conditions due to the absence of natural convection effects. Such materials have several beneficial properties that can improve the human life. An example is the synthesis of protein crystals with improved structure that can be determined for the production of advanced drugs. In the past experiments conducted aboard several space platforms, however, g-jitter induced convective flow may have resulted in certain effects that reduced the quality of the produced crystals. To investigate the effects of g-jitter on the motion of small particles, experiments were conducted under normal gravity by suspending spherical stainless steel particles of different sizes with a thin wire or synthetic silk thread in a rectangular fluid cell. The fluid viscosities were 350 and 1,000 times higher than water. To produce the g-jitter induced motion in the fluid, the cell was subjected to horizontal sinusoidal vibrations with different frequencies and amplitudes. The focus of the experiments so far has been on vibration-induced force on the particle vibrating parallel to a near wall. Relatively low viscosity fluids such as water have been previously determined to produce a force on the particle which attracts the particle to the nearest fluid cell wall. The present experiments with a more viscous fluid have revealed an interesting change in the force from attraction in low viscosity fluids to repulsion in high viscosity liquids. Moreover, the repulsion force has been observed to increase with an increase in the fluid viscosity and the fluid cell amplitude. A numerical code, Partflow3d, has also been used to predict the vibration effects on the particle. Although, based on the objectives of this study, the numerical simulations were conducted only for a wire-free particle under microgravity, their results were qualitatively in agreement with the experimental results. The numerical simulations also revealed that the physical mechanism of the hydrodynamic attraction-repulsion force on the particle is related to Bernoulli’s principle of reduced pressure in high velocity zones in the fluid surrounding the particle. The results so far have shown new aspects of the g-jitter induced motion of the particle near a fluid cell wall. Better understanding of the forces affecting the particles in a fluid cell subjected to small vibrations, can reveal novel ways to produce new advanced materials and also improve material processing both in microgravity and normal gravity conditions.

Production of protein and semi-conductor crystals with advanced quality and properties is considered to be possible under microgravity conditions due to the absence of natural convection effects. Such materials have several beneficial properties that can improve the human life. An example is the synthesis of protein crystals with improved structure that can be determined for the production of advanced drugs. In the past experiments conducted aboard several space platforms, however, g-jitter induced convective flow may have resulted in certain effects that reduced the quality of the produced crystals. To investigate the effects of g-jitter on the motion of small particles, experiments were conducted under normal gravity by suspending spherical stainless steel particles of different sizes with a thin wire or synthetic silk thread in a rectangular fluid cell. The fluid viscosities were 350 and 1,000 times higher than water. To produce the g-jitter induced motion in the fluid, the cell was subjected to horizontal sinusoidal vibrations with different frequencies and amplitudes. The focus of the experiments so far has been on vibration-induced force on the particle vibrating parallel to a near wall. Relatively low viscosity fluids such as water have been previously determined to produce a force on the particle which attracts the particle to the nearest fluid cell wall. The present experiments with a more viscous fluid have revealed an interesting change in the force from attraction in low viscosity fluids to repulsion in high viscosity liquids. Moreover, the repulsion force has been observed to increase with an increase in the fluid viscosity and the fluid cell amplitude. A numerical code, Partflow3d, has also been used to predict the vibration effects on the particle. Although, based on the objectives of this study, the numerical simulations were conducted only for a wire-free particle under microgravity, their results were qualitatively in agreement with the experimental results. The numerical simulations also revealed that the physical mechanism of the hydrodynamic attraction-repulsion force on the particle is related to Bernoulli’s principle of reduced pressure in high velocity zones in the fluid surrounding the particle. The results so far have shown new aspects of the g-jitter induced motion of the particle near a fluid cell wall. Better understanding of the forces affecting the particles in a fluid cell subjected to small vibrations, can reveal novel ways to produce new advanced materials and also improve material processing both in microgravity and normal gravity conditions.

With the development of mechanical fault diagnosis technology, complex mechanical systems do not need to be shut down periodically for the maintenance. The working condition of the mechanical systems can be monitored by analyzing the wear metal particles in the systems' lubricating oil. However, the output signals of the monitoring sensor are non-stationary. In some case the particle signals are overlapped with each other. The goal of this thesis is to find a method to decompose those overlapped particle signals, and then count the particle number in the lubricating oil. At the beginning EMD method was introduced in the experiment because of the character of the sensor signals. In this project, because EMD method is sensitive to the noise in the original signals, an improved version of EMD, EEMD method was implemented. Finally, a post processing method was used to get a better result.