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1
Krapohl, David, Christer Fröjdh, Erik Fröjdh, D. Maneuski, and Hans-Erik Nilsson. "Investigation of charge collection in a CdTe-Timepix detector." Mittuniversitetet, Avdelningen för elektronikkonstruktion, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-18946.
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Energy calibration of CdTe detectors is usually done using known reference sources disregarding the exact amount of charge that is collected in the pixels. However, to compare detector and detector model the quantity of charge collected is needed. We characterize the charge collection in a CdTe detector comparing test pulses, measured data and an improved TCAD simulation model [1]. The 1 mm thick detector is bump-bonded to a TIMEPIX chip and operating in Time-over-Threshold (ToT) mode. The resistivity in the simulation was adjusted to match the detector properties setting a deep intrinsic donor level [2]. This way it is possible to adjust properties like trap concentration, electron/hole lifetime and mobility in the simulation characterizing the detector close to measured data cite [3].
2
McConkey, Nicola. "Detector development for a neutrino detector with combined optical and charge readout in room temperature liquids." Thesis, University of Warwick, 2015. http://wrap.warwick.ac.uk/69105/.
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A room temperature liquid scintillator time projection chamber has the potential to give both ne grained tracking and calorimetry, analogous to liquid argon, only without the cryogenic infrastructure. This type of detector would be invaluable as a cost effective, large volume detector for use in neutrino physics. This motivates the search for candidate liquids with both excellent charge transport properties and optical properties. This work presents results from tests of five dielectric room temperature liquid scintillators; Di isopropyl naphthalene, Phenyl xylyl ethane, Linear alkyl benzene, Mono isopropyl biphenyl, and Mono isopropyl naphthalene, whose charge transport properties are investigated for the first time. The results are also presented from room temperature liquids Tetramethyl pentane, and Cyclopentane, whose optical properties have not previously been investigated. The liquids tested have shown favourable properties, although none of the above liquids has been found to have both charge transport and scintillation light at a suitable level for use in a neutrino detector.
3
Krapohl, David. "Monte Carlo and Charge Transport Simulation of Pixel Detector Systems." Doctoral thesis, Mittuniversitetet, Avdelningen för elektronikkonstruktion, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-24763.
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This thesis is about simulation of semiconductor X-ray and particledetectors. The simulation of a novel coating for solid state neutrondetectors is discussed as well as the implementation of a simulationframework for hybrid pixel detectors.Today’s most common thermal neutron detectors are proportionalcounters, that use 3He gas in large tubes or multi wire arrays. Globalnuclear disarmament and the increase in use for homeland securityapplications has created a shortage of the gas which poses a problemfor neutron spallation sources that require higher resolution and largersensors. In this thesis a novel material and clean room compatible pro-cess for neutron conversion are discussed. Simulations and fabricationhave been executed and analysed in measurements. It has been proventhat such a device can be fabricated and detect thermal neutrons.Spectral imaging hybrid pixel detectors like the Medipix chipare the most advanced imaging systems currently available. Thesechips are highly sophisticated with several hundreds of transistors perpixel to enable features like multiple thresholds for noise free photoncounting measurements, spectral imaging as well as time of arrivalmeasurements. To analyse and understand the behaviour of differentsensor materials bonded to the chip and to improve development offuture generations of the chip simulations are necessary. Generally, allparts of the detector system are simulated independently. However, itis favourable to have a simulation framework that is able to combineMonte Carlo particle transport, charge transport in the sensor as wellas analogue and digital response of the pixel read-out electronics. Thisthesis aims to develop such a system that has been developed withGeant4 and analytical semiconductor and electronics models. Further-more, it has been verified with data from measurements with severalMedipix and Timepix sensors as well as TCAD simulations.Results show that such a framework is feasible even for imagingsimulations. It shows great promise to be able to be extended withfuture pixel detector designs and semiconductor materials as well asneutron converters to aim for next generation imaging devices.
4
Engelhardt, Felix. "Evaluation of Detector and Intensity Reliability in Charge Density Studies." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2017. http://hdl.handle.net/11858/00-1735-0000-002E-E337-2.
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Hurle, Bernard Alfred. "The charge coupled device as a low light detector in beam foil spectroscopy." Thesis, University of Kent, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332296.
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Hoang, Vu Dinh. "Charge transport study of InGaAs two-color QWIPs." Thesis, Monterey California. Naval Postgraduate School, 2004. http://hdl.handle.net/10945/1574.
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Approved for public release, distribution is unlimitedIn this thesis, a series of experiments were performed to characterize the material properties of InGaAs/GaAs for use in a two-color quantum-well IR photodetector (QWIP) design. Results from room temperature studies using cathodoluminescence and photoluminescence indicated light emission at 858 nm and 1019 nm from GaAs and InGaAs, respectively. Using a direct transport imaging technique, an edge dislocation pattern was observed and shown to be confined to the InGaAs layer of the material. A dislocation density measurement was performed and was shown to be less than 2000 lines/cm. Quantitative intensity level measurements indicated fluctuation in the region of dislocations to be less than 30% of the signal to background level. Finally, a spot mode study using the direct transport imaging method was performed to evaluate the feasibility of using this technique for contact-less diffusion length measurements.
Civilian, Department of Air Force
7
Sims, Gary Robert. "Characterization of a charge injection device detector for atomic emission spectroscopy." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184735.
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A Charge Injection Device (CID) detector has been evaluated as a detector for simultaneous multielement atomic emission spectroscopy. The CID was incorporated into a special liquid nitrogen cooled, computer controlled camera system. Electro-optical characterization of the CID and camera system included determination of readout noise, quantum efficiency, spatial crosstalk, temporal hysteresis, spatial response uniformity, and linear dynamic range. The CID was used as a spectroscopic detector for an echelle grating spectrometer equipped with a direct current plasma emission source. The spectrometer was a standard commercial instrument modified to provide a reduced image format more suitable for use with the CID detector. The optical characteristics of this spectrometer, including wavelength coverage, and optical aberrations are described. The spectroscopic system was evaluated with respect to detection limits, linear dynamic range, and accuracy in both single element and simultaneous multielement modes. Detection limits compared well to literature values reported for photomultiplier tube detector based systems under similar conditions. CID detection limits were superior in the near infrared and visible wavelength region, comparable in the middle UV, and higher in the far UV. The detection limits were determined to be limited by background radiation shot noise. Several elements of a certified standard reference material were simultaneously determined in order to assess the accuracy of the spectroscopic system. The results were highly accurate, even when operating near or below the 3σ limits of detection. Spectral interferences for elements were avoided by using several analytical lines for each element. The results of these investigations indicate that the CID is a superior multichannel detector for analytical atomic emission spectrometry. The capability to simultaneously monitor a wide, continuous spectral range with high spatial resolution, high dynamic range, low readout noise, and insignificant signal crosstalk is now possible. Many analytical benefits of this approach, such as the potential capability to perform rapid qualitative and semiquantitative analysis and the ability to select the optimum spectral lines for highly accurate quantitative analysis are now readily achievable.
8
Mauri, Nicoletta <1980>. "Measurement of the atmospheric muon charge ratio with the OPERA detector." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3932/.
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The atmospheric muon charge ratio, defined as the number of positive over negative charged muons, is an interesting quantity for the study of high energy hadronic interactions in atmosphere and the nature of the primary cosmic rays. The measurement of the charge ratio in the TeV muon energy range allows to study the hadronic interactions in kinematic regions not yet explored at accelerators.
The OPERA experiment is a hybrid electronic detector/emulsion apparatus, located in the underground Gran Sasso Laboratory, at an average depth of 3800 meters water equivalent (m.w.e.). OPERA is the first large magnetized detector that can measure the muon charge ratio at the LNGS depth, with a wide acceptance for cosmic ray muons coming from above.
In this thesis, the muon charge ratio is measured using the spectrometers of the OPERA detector in the highest energy region.
The charge ratio was computed separately for single and for multiple muon events, in order to select different primary cosmic ray samples in energy and composition. The measurement as a function of the surface muon energy is used to infer parameters characterizing the particle production in atmosphere, that will be used to constrain Monte Carlo predictions.
Finally, the experimental results are interpreted in terms of cosmic ray and particle physics models.
9
Whitehead, Samuel Robert. "A measurement of the W boson charge asymmetry with the ATLAS detector." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:3eba7629-7ec3-4536-afd1-a804c6fc48f4.
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Uncertainties on the parton distribution functions (PDFs), in particular those of the valence quarks, can be constrained at LHC energies using the charge asymmetry in the production of W± bosons. This thesis presents a measurement of the electron channel, lepton charge asymmetry using 497 pb-1 of data recorded with the ATLAS detector in 2011. The measurement is included in PDF fits using the machinery of HERAPDF and is found to have some constraining power beyond that of existing W charge asymmetry measurements.
10
Hedges, Sarah Jane. "Production and reliability aspects of the CCD mosaic for the SLD Vertex Detector." Thesis, Brunel University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305193.
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Majdi, Saman. "Experimental Studies of Charge Transport in Single Crystal Diamond Devices." Doctoral thesis, Uppsala universitet, Elektricitetslära, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-173599.
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Diamond is a promising material for high-power, high-frequency and high- temperature electronics applications, where its outstanding physical properties can be fully exploited. It exhibits an extremely high bandgap, very high carrier mobilities, high breakdown field strength, and the highest thermal conductivity of any wide bandgap material. It is therefore an outstanding candidate for the fastest switching, the highest power density, and the most efficient electronic devices obtainable, with applications in the RF power, automotive and aerospace industries. Lightweight diamond devices, capable of high temperature operation in harsh environments, could also be used in radiation detectors and particle physics applications where no other semiconductor devices would survive. The high defect and impurity concentration in natural diamond or high-pressure-high-temperature (HPHT) diamond substrates has made it difficult to obtain reliable results when studying the electronic properties of diamond. However, progress in the growth of high purity Single Crystal Chemical Vapor Deposited (SC-CVD) diamond has opened the perspective of applications under such extreme conditions based on this type of synthetic diamond. Despite the improvements, there are still many open questions. This work will focus on the electrical characterization of SC-CVD diamond by different measurement techniques such as internal photo-emission, I-V, C-V, Hall measurements and in particular, Time-of-Flight (ToF) carrier drift velocity measurements. With these mentioned techniques, some important properties of diamond such as drift mobilities, lateral carrier transit velocities, compensation ratio and Schottky barrier heights have been investigated. Low compensation ratios (ND/NA) < 10-4 have been achieved in boron-doped diamond and a drift mobility of about 860 cm2/Vs for the hole transit near the surface in a lateral ToF configuration could be measured. The carrier drift velocity was studied for electrons and holes at the temperature interval of 80-460 K. The study is performed in the low-injection regime and includes low-field drift mobilities. The hole mobility was further investigated at low temperatures (10-80 K) and as expected a very high mobility was observed. In the case of electrons, a negative differential mobility was seen in the temperature interval of 100-150K. An explanation for this phenomenon is given by the intervally scattering and the relation between hot and cold conduction band valleys. This was observed in direct bandgap semiconductors with non-equivalent valleys such as GaAs but has not been seen in diamond before. Furthermore, first steps have been taken to utilize diamond for infrared (IR) radiation detection. To understand the fundamentals of the thermal response of diamond, Temperature Coefficient of Resistance (TCR) measurements were performed on diamond Schottky diodes which are a candidate for high temperature sensors. As a result, very high TCR values in combination with a low noise constant (K1/f) was observed.
12
Robbins, Mark Stanford. "Radiation damage effects in charge coupled devices." Thesis, Brunel University, 1992. http://bura.brunel.ac.uk/handle/2438/5454.
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The effects of Sr90 beta radiation and Co60 gamma radiation on the operation of EEV buried channel charge coupled devices (CCDs) have been studied. This work was instigated by the need to qualify CCDs for the SLD vertex detector. However, the work is also relevant to other small signal, low noise applications. The results of the batch qualification are presented and the data base of ionising radiation effects on EEV CCDs has been extended to include the effects of irradiation whilst clocking at 180K. Particular attention has been aimed at investigating the charge transfer degradation due to low levels of bulk defects. The measured energy level, capture cross section and introduction rate of the main radiation induced defect agrees well with published results for the Si-E centre. Annealing studies are also presented. A model for the charge transfer degradation is proposed. This includes the effects of temperature, readout rate, signal density and irradiation type and energy. Observations are also presented on the effect of irradiation on the noise characteristics of the single stage output circuit. For low noise applications the output is run in buried channel mode. In this mode the increase in noise is dominated by the change in the operating point of the output MOSFET.
13
Shi, Xiaochuan. "Effect of Electron Bombardment on the Size Distribution of Negatively Charged Droplets Produced by Electrospray." Digital WPI, 2012. https://digitalcommons.wpi.edu/etd-dissertations/15.
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This study explores an innovative approach to control the droplet size distribution produced by an electrospray with the intention of eventually being able to deliver precisely controlled quantities of precursor materials for nanofabrication. The technique uses a thermionic cathode to charge the droplets in excess of the Rayleigh limit, leading to droplet breakup or fission. The objective of these experiments was to assess whether the proposed technique could be used to produce a new droplet size distribution with a smaller mean droplet diameter without excessively broadening the distribution. An electrospray was produced in a vacuum chamber using a dilute mixture of ionic liquid. During their transit from the capillary source to a diagnostic instrument, the resulting droplets were exposed to an electron stream with controlled flux and kinetic energy. The droplets were sampled in an inductive charge detector to characterize changes in the size distribution. A positively biased anode electrode was used to collect electron current during droplet exposure. This collected current was used as the primary control variable and used as a measure of the electron flux. The anode bias voltage was a secondary control variable and used as a measure of the electron energy. In a series of seven tests, two sets showed evidence of fission having occurred resulting in the formation of two droplet populations after electron bombardment. Three sets of results showed evidence of a single droplet population after electron bombardment, but shifted to a smaller mean diameter, and one set of results was inconclusive. Because of the large standard deviation in the droplet diameter distributions, the two cases in which a second population was evident were the strongest indication that droplet fission had occurred.
14
Lohwasser, Kristin. "The W Charge Asymmetry : Measurement of the Proton Structure with the ATLAS Detector." Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526486.
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Yousef, Hazem [Verfasser]. "Energy dependent charge spread function in a dedicated synchrotron beam pnCCD detector / Hazem Yousef." Siegen : Universitätsbibliothek der Universität Siegen, 2011. http://d-nb.info/1017706328/34.
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Haugen, Christopher Jon. "Charge transport in stabilized a-Se films used in x-ray image detector applications." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0028/NQ37887.pdf.
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Rozsa, Jace. "Characterization and Optimization of an Image Charge Detector for the Measurement of Martian Dust." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/8700.
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Image charge detector (ICD) technology has existed for decades. However, not until recently has an ICD been proposed for use in space exploration, specifically for studying the characteristics of the dust on Mars. Characterizing the dust on Mars is crucial for designing equipment to aid manned missions. It also improves our understanding of Mars' climate and weather systems. An ICD utilizing printed circuit board (PCB) electrodes, coupled with a custom differential amplifier, is best suited for this type of measurement because of its light weight, simplicity, and noise performance. The noise floor of our particular amplifier is measured to be 1030 e- and simulated to be as low as 140 e-. Both of these measurements are taken without averaging. To further verify and understand this device, I developed a novel simulation method using ANSYS Maxwell 3D to simulate the interaction between the charged particle and the electrodes of the ICD. The results from this simulation are then easily passed to Cadence where we can clearly see the response of the custom amplifier to the charged particle. This knowledge is used to study various types of electrode geometry for improved noise performance, as well as understand how particle trajectory affect the resulting signal. Once the validity of the Maxwell simulation is established, I use it, along with experimental data and a mathematical model based on conformal mapping, to optimize the ICD for noise performance. I find that the maximum noise performance does not lie in simply increasing the number of sensing stages, as was previously thought. The optimum number of stages is a function of the parasitic capacitance of the amplifier, with the greater parasitic capacitance leading to the greater number of stages for the optimum.
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Norlin, Börje. "Photon Counting X-ray Detector Systems." Licentiate thesis, Mid Sweden University, Department of Information Technology and Media, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-41.
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This licentiate thesis concerns the development and characterisation of X-ray imaging detector systems. “Colour” X-ray imaging opens up new perspectives within the fields of medical X-ray diagnosis and also in industrial X-ray quality control. The difference in absorption for different “colours” can be used to discern materials in the object. For instance, this information might be used to identify diseases such as brittle-bone disease. The “colour” of the X-rays can be identified if the detector system can process each X-ray photon individually. Such a detector system is called a “single photon processing” system or, less precise, a “photon counting system”.
With modern technology it is possible to construct photon counting detector systems that can resolve details to a level of approximately 50 µm. However with such small pixels a problem will occur. In a semiconductor detector each absorbed X-ray photon creates a cloud of charge which contributes to the picture achieved. For high photon energies the size of the charge cloud is comparable to 50 µm and might be distributed between several pixels in the picture. Charge sharing is a key problem since, not only is the resolution degenerated, but it also destroys the “colour” information in the picture.
The problem involving charge sharing which limits “colour” X-ray imaging is discussed in this thesis. Image quality, detector effectiveness and “colour correctness” are studied on pixellated detectors from the MEDIPIX collaboration. Characterisation measurements and simulations are compared to be able to understand the physical processes that take place in the detector. Simulations can show pointers for the future development of photon counting X-ray systems. Charge sharing can be suppressed by introducing 3D-detector structures or by developing readout systems which can correct the crosstalk between pixels.
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Schürmann, Christian Joseph. "Chemical Concepts and X-ray Technologies challenged by Charge Density." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://hdl.handle.net/11858/00-1735-0000-002E-E5EC-B.
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Krasel, Olaf [Verfasser]. "Charge collection in irradiated silicon detectors : a study of the operation conditions of silicon sensors in the ATLAS pixel detector / Olaf Krasel." Dortmund : Universitätsbibliothek Technische Universität Dortmund, 2004. http://d-nb.info/1011531879/34.
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Liang, Yuanling. "Utilization of a scientifically operated charge-coupled device detector for high-performance thin-layer chromatographic analysis." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282688.
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A high-performance thin-layer chromatographic (HPTLC) separation system coupled with a scientifically operated charge-couple device detector (CCD) has been developed to improve the identification and quantitative analysis of pharmaceutical products and natural toxins. The combination of the fast, easy and high throughput properties of TLC, high speed, sensitivity, wide dynamic range of the CCD detector, and the high reproducibility and accuracy of the micro-nebulization sampler can be used to facilitate pharmaceutical industrial quality control and food industrial safety control. The application of this system in these areas has shown significant improvement in sensitivity, precision, and accuracy.
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Narayanan, Ajay M. 1966. "Measurement of the charge asymmetry of muons from W boson decay at the D-zero detector." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/284339.
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We have measured the charge asymmetry of muons produced in W boson decay as a function of muon pseudorapidity. The W bosons were produced in pp̄ collisions at √s = 1.8 TeV at the Fermilab Tevatron and recorded by the D⊘ detector during the run period 1992-1993 (run 1A) and 1994-1995 (run 1B). The combined data for both periods consists of 8831 W → μν decays withημ
< 1.0 selected from events corresponding to an integrated luminosity of 61.9 pb⁻¹ and 664 decays with 1.0 ≤
ημ
< 1.6 corresponding to an integrated luminosity of 44.5 pb⁻¹.
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Al, Sabbagh Mhd Zaher. "0.18um phase/frequency detector and charge pump design for digital video broadcasting for handheld's phase-locked-loop systems." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1196281141.
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Gabrysch, Markus. "Charge Transport in Single-crystalline CVD Diamond." Doctoral thesis, Uppsala universitet, Elektricitetslära, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-122794.
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Diamond is a semiconductor with many superior material properties such as high breakdown field, high saturation velocity, high carrier mobilities and the highest thermal conductivity of all materials. These extreme properties, as compared to other (wide bandgap) semiconductors, make it desirable to develop single-crystalline epitaxial diamond films for electronic device and detector applications. Future diamond devices, such as power diodes, photoconductive switches and high-frequency field effect transistors, could in principle deliver outstanding performance due to diamond's excellent intrinsic properties. However, such electronic applications put severe demands on the crystalline quality of the material. Many fundamental electronic properties of diamond are still poorly understood, which severely holds back diamond-based electronic device and detector development. This problem is largely due to incomplete knowledge of the defects in the material and due to a lack of understanding of how these defects influence transport properties. Since diamond lacks a shallow dopant that is fully thermally activated at room temperature, the conventional silicon semiconductor technology cannot be transferred to diamond devices; instead, new concepts have to be developed. Some of the more promising device concepts contain thin delta-doped layers with a very high dopant concentration, which are fully activated in conjunction with undoped (intrinsic) layers where charges are transported. Thus, it is crucial to better understand transport in high-quality undoped layers with high carrier mobilities. The focus of this doctoral thesis is therefore the study of charge transport and related electronic properties of single-crystalline plasma-deposited (SC-CVD) diamond samples, in order to improve knowledge on charge creation and transport mechanisms. Fundamental characteristics such as drift mobilities, compensation ratios and average pair-creation energy were measured. Comparing them with theoretical predictions from simulations allows for verification of these models and improvement of the diamond deposition process.
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Rubbo, Francesco. "Measurements of the charge asymmetry in top quark pair production at the LHC with the ATLAS detector." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/284972.
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El quark top, descubierto en 1995 en los experimentos CDF y D0 en el colisionador protón-antiprotón Tevatron en Fermilab (Chicago, USA), es la partícula elemental más pesada conocida, con una masa comparable a la de un átomo de tungsteno. Esta propiedad, no explicada por el Modelo Estándar, confiere al quark top un papel especial en el contexto de modelos teóricos más allá del Modelo Estándar, muchos de los cuales predicen nuevas partículas que se acoplan preferentemente al quark top debido a su alta masa. Después de una década de estudios en el Tevatron (2001-2011), no se han descubierto indicios significativos de nueva física en las propiedades del quark top. La única excepción es la medida de la asimetría adelante-atrás en la producción de parejas top-antitop en colisiones protón-antiprotón en el Tevatron, donde se han encontrado un exceso de aproximadamente dos desviaciones estándar con respecto a la predicción del Modelo Estándar. Esta medida indica que en promedio los quarks top en sucesos top-antitop se producen en la dirección del haz de protones con mayor frecuencia que los quarks antitop. Aunque el Modelo Estándar predice una pequeña asimetría adelante-atrás debido a la interacción fuerte, la presencia de nuevas partículas pesadas contribuyendo a la producción de parejas top-antitop podría dar lugar a un exceso como el observado. Por desgracia, tras el cese de operaciones del Tevatron en Septiembre del 2011, el análisis de todos los datos de los experimentos CDF y D0 no han permitido alcanzar una conclusión definitiva con respecto a esta anomalía.
Esta tesis doctoral está centrada en la medida de precisión de la asimetría de carga en la producción de parejas top-antitop en colisiones protón-protón en el LHC usando las muestras completas de datos acumulados por el detector ATLAS a energías del centro de masas de 7 TeV y 8 TeV, correspondientes a luminosidades integradas de aproximadamente 5 fb-1 y 20 fb-1, respectivamente. La asimetría de carga AC en el LHC, relacionada con la asimetría adelante-atrás en el Tevatron, es sensible a los mismos efectos de nueva física que causarían una desviación en las medidas del Tevatron. En esta tesis doctoral se utiliza el canal semileptónico para hacer medidas inclusivas y diferenciales de la asimetría de carga en sucesos top-antitop. La cinemática de producción de la pareja top-antitop es reconstruida a partir del productos de la desintegración semileptónica y un metodo de unfolding bayesiano es utilizado para estimar AC al nivel partónico. Usando los datos a 7 TeV, se ha alcanzado una precisión 1% en la medida de la asimetría de carga a nivel inclusivo. También se han realizado medidas diferenciales en función de la masa invariante, ángulo de producción con respecto al eje del haz de protones y momento transverso de la pareja top-antitop. Usando los datos a 8 TeV, la precisión obtenida es de 0.5% en la medida de la asimetría de carga a nivel inclusivo, y también se ha realizado la medida diferencial en función de la masa invariante de la pareja top-antitop. La comparación de todas las medidas con las predicciones teóricas indican consistencia con el Modelo Estándar.The top quark, discovered in 1995 at the CDF and D0 experiments at Fermilab’s Tevatron proton-antiproton collider, is the heaviest known elementary particle, with a mass comparable to the atomic mass of tungsten. This property, not explained by the Standard Model (SM), gives a special role to the top quark in the context of theoretical models beyond the Standard Model. Many of the models predict that new particles would preferably couple with the top quark, due to its high mass. After a decade of studies at the Tevatron (2001-2011), no signs of new physics have been discovered in the properties of the top quark, with the exception of the forward-backward asymmetry in top quark pair production, where an excess of about two standard deviations from the SM prediction has been found. This measurement shows that, in average, the top quark in top-antitop events is produced in the proton direction more often than the antitop quark. Even though the SM predicts a small forward-backward asymmetry due to the strong interaction, the presence of new heavy particles contributing to the top-antitop pair production could cause the observed excess. Unfortunately the Tevatron operation terminated on September 2012, and the analysis of the full datasets collected by the CDF and D0 experiments did not provide a final answer with respect to this anomaly. This dissertation describes the precise measurement of the charge asymmetry AC in top-antitop pair production in proton-proton collisions at LHC, using the full dataset collected with the ATLAS detector at center-of-mass energies of 7 TeV and 8 TeV, corresponding to integrated luminosities of about 5 fb-1 and 20 fb-1, respectively. The LHC charge asymmetry, related to the Tevatron forward-backward asymmetry, is a complementary probe of the same new physics effects that could be responsible for the Tevatron excess. The lepton+jets channel is considered to perform inclusive and differential measurements of the charge asymmetry in top quark pair events. The kinematics of the top-antitop pair is reconstructed from the semileptonic decay products, and a Bayesian unfolding procedure is employed to estimate AC at the parton level. Using the dataset at 7 TeV, a 1% precision is achieved for the inclusive measurement. Differential AC measurements as a function of the invariant mass, the rapidity and the transverse momentum of the top-antitop pair are also presented. Using the dataset at 8 TeV, a 0.5% precision is achieved for the inclusive measurement, and the differential AC measurement as a function of the invariant mass of the top-antitop pair is performed as well. All measurements are found to be consistent with the SM predictions.
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Kolczynski, Jeffrey Daniel. "Speciation and elemental analysis employing a custom designed echelle spectrometer and a charge injection device array detector." Diss., The University of Arizona, 1994. http://hdl.handle.net/10150/186754.
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A custom designed echelle spectrometer coupled with a charge injection device (CID) detector was applied to a series of analytical challenges in atomic emission spectroscopy (AES). By taking advantage of the two dimensional spectral format of an echelle/CID spectrometer, simultaneous, multi-elemental atomic spectroscopic information can be directly obtained. A direct current plasma (DCP) was utilized as the AES excitation source. The echelle/CID system has a large spectral elemental database. Through the utilization of vast amounts of spectral information and the application of fundamental spectroscopic principles, an intelligent analytical system was designed to make certain routine and non-routine decisions with minimal intervention by the analyst. The utility of the echelle/CID system is investigated through its application to several analytical challenges. These challenges include automated-qualitative analysis, quantitative analysis for samples of limited size (microgram quantities) and qualitative and quantitative chromatographic analysis of various metal species. The results of an analyses generated by an automated-qualitative routine for the determination of elemental constituents in environmental contaminants, unknown particulate from a hospital air delivery system and laboratory waste samples are presented. The ability to simultaneously integrate multi-elemental information makes the echelle/CID system well suited for the quantitative analysis of trace sample quantities. The echelle/CID system was employed in the trace determination of 1000, 400 and 40 micrograms/ml NBS standard reference material 1633a, coal fly ash, samples. Finally, the echelle/CID AES system is utilized as an element selective detector for high performance liquid chromatography (HPLC). HPLC separation methods were developed for the quantitative analysis of iron and copper oxidation states. The results of the HPLC separation of iron(II) and iron(III) through their interactions with the mobile phase modifier, 8-hydroxyquinoline are presented. The results of the HPLC separation of copper(I) and copper(II) are in an mobile phase containing 2,9 dimethyl 1,10 phenanthroline are presented. A novel solid phase extraction (SPE) method for Cu(I) was also developed. The results of the SPE method used to monitor the Cu(I) concentration in a series of electroless copper plating baths are presented.
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Norlin, Börje. "Characterisation and application of photon counting X-ray detector systems." Doctoral thesis, Mittuniversitetet, Institutionen för informationsteknologi och medier, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-38.
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This thesis concerns the development and characterisation of X-ray imaging systems based on single photon processing. “Colour” X-ray imaging opens up new perspectives within the fields of medical X-ray diagnosis and also in industrial X-ray quality control. The difference in absorption for different “colours” can be used to discern materials in the object. For instance, this information might be used to identify diseases such as brittle-bone disease. The “colour” of the X-rays can be identified if the detector system can process each X-ray photon individually. Such a detector system is called a “single photon processing” system or, less precise, a “photon counting system”. With modern technology it is possible to construct photon counting detector systems that can resolve details to a level of approximately 50 µm. However with such small pixels a problem will occur. In a semiconductor detector each absorbed X-ray photon creates a cloud of charge which contributes to the image. For high photon energies the size of the charge cloud is comparable to 50 µm and might be distributed between several pixels in the image. Charge sharing is a key problem since, not only is the resolution degenerated, but it also destroys the “colour” information in the image. This thesis presents characterisation and simulations to provide a detailed understanding of the physical processes concerning charge sharing in detectors from the MEDIPIX collaboration. Charge summing schemes utilising pixel to pixel communications are proposed. Charge sharing can also be suppressed by introducing 3D-detector structures. In the next generation of the MEDIPIX system, Medipix3, charge summing will be implemented. This system, equipped with a 3D-silicon detector, or a thin planar high-Z detector of good quality, has the potential to become a commercial product for medical imaging. This would be beneficial to the public health within the entire European Union.Denna avhandling berör utveckling och karaktärisering av fotonräknande röntgensystem. ”Färgröntgen” öppnar nya perspektiv för medicinsk röntgendiagnostik och även för materialröntgen inom industrin. Skillnaden i absorption av olika ”färger” kan användas för att särskilja olika material i ett objekt. Färginformationen kan till exempel användas i sjukvården för att identifiera benskörhet. Färgen på röntgenfotonen kan identifieras om detektorsystemet kan detektera varje foton individuellt. Sådana detektorsystem kallas ”fotonräknande” system. Med modern teknik är det möjligt att konstruera fotonräknande detektorsystem som kan urskilja detaljer ner till en upplösning på circa 50 µm. Med så små pixlar kommer ett problem att uppstå. I en halvledardetektor ger varje absorberad foton upphov till ett laddningsmoln som bidrar till den erhållna bilden. För höga fotonenergier är storleken på laddningsmolnet jämförbar med 50 µm och molnet kan därför fördelas över flera pixlar i bilden. Laddningsdelning är ett centralt problem delvis på grund av att bildens upplösning försämras, men framför allt för att färginformationen i bilden förstörs. Denna avhandling presenterar karaktärisering och simulering för att ge en mer detaljerad förståelse för fysikaliska processer som bidrar till laddningsdelning i detektorer från MEDIPIX-projekter. Designstrategier för summering av laddning genom kommunikation från pixel till pixel föreslås. Laddningsdelning kan också begränsas genom att introducera detektorkonstruktioner i 3D-struktur. I nästa generation av MEDIPIX-systemet, Medipix3, kommer summering av laddning att vara implementerat. Detta system, utrustat med en 3D-detektor i kisel, eller en tunn plan detektor av högabsorberande material med god kvalitet, har potentialen att kunna kommersialiseras för medicinska röntgensystem. Detta skulle bidra till bättre folkhälsa inom hela Europeiska Unionen.
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Vannerom, David. "Search for new physics in the dark sector with the CMS detector: From invisible to low charge particles." Doctoral thesis, Universite Libre de Bruxelles, 2019. https://dipot.ulb.ac.be/dspace/bitstream/2013/293380/4/thesis.pdf.
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The Standard Model of particle physics is the framework that describes all known phenomenaand interactions between elementary particles. It has proven to give outstanding results overthe years and was succesfully completed with the discovery of the Brout-Englert-Higgs boson in2012 by the ATLAS and CMS collaborations at CERN. However, several observations escape itsreach: the matter-antimatter asymmetry, the nature of Dark Matter or the quantization of theelectric charge. These are all examples of measured facts not explained by the Standard Modelformalism and that call for an extension to a Beyond the Standard Model (BSM) theory. In thisthesis, we have looked for evidence of new physics using proton-proton collision data producedby CERN’s Large Hadron Collider (LHC) at a center-of-mass energy of 13 TeV. Collected from2016 to 2018 by the CMS detector, it corresponds to an integrated luminosity of 136/fb .Afteran introduction to the theoretical context and the experimental tools, two analyses are presented.The first one is a search for Dark Matter particles recoiling against a jet and leaving the detectorunnoticed. With this ”monojet” analysis, we are able to exclude mediator masses up to 1.8TeV, and masses of Dark Matter particles up to 700 GeV. The second analysis is a search forfractionally charged particles. Using the fact that their stopping power is lower than StandardModel particles, we are able to exclude their existence up to masses of 765 GeV for a charge of2/3 e.Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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Al, Sabbagh Mhd Zaher. "0.18μm phase/frequency detector and charge pump design for digital video broadcasting for handheld’s phase-locked-loop systems." The Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1196281141.
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Xu, Cheng. "A Segmented Silicon Strip Detector for Photon-Counting Spectral Computed Tomography." Doctoral thesis, KTH, Medicinsk avbildning, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-105614.
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Spectral computed tomography with energy-resolving detectors has a potential to improve the detectability of images and correspondingly reduce the radiation dose to patients by extracting and properly using the energy information in the broad x-ray spectrum. A silicon photon-counting detector has been developed for spectral CT and it has successfully solved the problem of high photon flux in clinical CT applications by adopting the segmented detector structure and operating the detector in edge-on geometry. The detector was evaluated by both the simulation and measurements. The effects of energy loss and charge sharing on the energy response of this segmented silicon strip detector with different pixel sizes were investigated by Monte Carlo simulation and a comparison to pixelated CdTe detectors is presented. The validity of spherical approximations of initial charge cloud shape in silicon detectors was evaluated and a more accurate statistical model has been proposed. A photon-counting energy-resolving application specific integrated circuit (ASIC) developed for spectral CT was characterized extensively by electrical pulses, pulsed laser and real x-ray photons from both the synchrotron and an x-ray tube. It has been demonstrated that the ASIC performs as designed. A noise level of 1.09 keV RMS has been measured and a threshold dispersion of 0.89 keV RMS has been determined. The count rate performance of the ASIC in terms of count loss and energy resolution was evaluated by real x-rays and promising results have been obtained. The segmented silicon strip detector was evaluated using synchrotron radiation. An energy resolution of 16.1% has been determined with 22 keV photons in the lowest flux limit, which deteriorates to 21.5% at an input count rate of 100 Mcps mm−2. The fraction of charge shared events has been estimated and found to be 11.1% for 22 keV and 15.3% for 30 keV. A lower fraction of charge shared events and an improved energy resolution can be expected by applying a higher bias voltage to the detector.QC 20121123
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Wang, Junting. "Miniaturized Electrostatic Ion Beam Trap Mass Analyzer." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3610.
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The electrostatic ion beam trap (EIBT) was designed by D. Zajfman during the previous decade. This ion trap combines many properties of the Fourier-transform ion cyclotron resonance (FTICR) mass analyzer and time-of-flight (TOF) mass analyzer. There are several advantages for the electrostatic ion beam trap. First, large mass-to-charge particles in an electrostatic field could be easier to analyze. Second, there is a folded flight path, which could make the mass analyzer smaller compared to conventional TOF mass analyzer. This principle of operation of this ion trap is analogous to an optical resonator. The ions are trapped in a voltage valley and oscillate between the two parallel sets of mirror electrodes with high voltages. In this thesis, I first describe a new type of miniaturized electrostatic ion beam trap mass analyzer that consists of two printed circuit boards (PCBs). The facing surfaces of these boards are imprinted with copper electrodes. The center of the boards is field free and at ground potential with ion mirrors and Einzel lenses on either side. A charge detector is attached to the center for recording the time-dependant motion of the ions in the field. The PCB-based EIBT design is easier to construct than the original EIBT mass analyzer. The electrostatic fields are optimized by adjusting the potential on the mirror electrodes as well as the geometry of the electrodes. Although nondestructive charge detection is much less sensitive for small ions, this detection is ideal for analysis of large ions. The planar electrostatic ion beam trap is inexpensive, small, and simple to operate. The PCB EIBT device was designed, built, and tested using metal samples such as copper and nickel. The electric field of the PCB EIBT is not the same as that of the original EIBT. Unfortunately, there were no ion signals captured in image charge detector. Another new type of miniaturized electrostatic ion beam trap was made by depositing electrodes onto Kapton film. Seven thin tin/copper traces (1 mm wide by 0.015 mm thick) were deposited onto each side of a flat, flexible circuit board substrate (Kapton film 0.15 mm thickness). The film was rolled to form a cylinder. The flexible EIBT is small (4.5 cm × 8 cm), and lightweight (~1 g). This device was tested using laser ablation of CsI. The CsI signals were detected by the charge detector, amplified and sent to the oscilloscope. Fourier transformation was used to convert the data to the frequency domain spectrum. The resolution of Cs+ is around 1000 (m/Δm) from initial flexible EIBT test. The mass accuracy of the Cs+ peak is better than 0.1%.
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Engelhardt, Felix [Verfasser], Dietmar [Akademischer Betreuer] Stalke, Dietmar [Gutachter] Stalke, and Francesca [Gutachter] Fabbiani. "Evaluation of Detector and Intensity Reliability in Charge Density Studies / Felix Engelhardt ; Gutachter: Dietmar Stalke, Francesca Fabbiani ; Betreuer: Dietmar Stalke." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2018. http://d-nb.info/1151700460/34.
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Tsionou, Dimitra. "Measurement of the differential production cross section of W bosons and charge asymmetry at √s = 7 TeV with the ATLAS detector." Thesis, University of Sheffield, 2013. http://etheses.whiterose.ac.uk/3844/.
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This document presents a measurement of the production cross section of W bosons and of its charge asymmetry in proton-proton collisions at a centre of mass energy of 7 TeV with the ATLAS detector. These measurements provide information on the momentum fraction of the protons carried by the partons contributing to the W production and therefore allow to better understand the parton distribution functions of the proton. The W candidate events are selected in the W→eν decay mode. The LAr electromagnetic calorimeter plays an important role in the detection of electrons and the author has worked on the on-line energy reconstruction in the LAr detectors. A subject which is treated in some detail is the evaluation of the charge misidentification rates for electrons and positrons. This is a key ingredient for charge related measurements such as the W charge asymmetry. In this document, the W production cross section times the branching ratio is studied inclusively, as a function of the lepton pseudorapidity and as a double differential measurement as a function of the lepton pseudorapidity and transverse energy. The charge asymmetry measurement is presented as a function of the lepton pseudorapidity and as a double differential measurement as well. The data were recorded by the ATLAS detector in 2011 and correspond to 4.7 fb⁻¹.
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Zhao, Wei. "Development of CMOS sensor with digital pixels for ILD vertex detector." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAE004/document.
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La thèse présente le développement de CPS (CMOS Pixel Sensors) intégré avec CAN au niveau du pixel pour les couches externes du détecteur de vertex de l’ILD (International Large Detector). Motivé par la physique dans l’ILC (International Linear Collider), une précision élevée est nécessaire pour les détecteurs. La priorité des capteurs qui montre sur les couches externes est une faible consommation d’énergie en raison du rapport élevé de couverture de la surface sensible (~90%) dans le détecteur de vertex. Le CPS intégré avec CAN est un choix approprié pour cette application. L’architecture de CAN de niveau colonne ne fournit pas une performance optimisée en termes de bruit et la consommation d’énergie. La conception de CAN au niveau du pixel a été proposée. Bénéficiant des sorties de pixels tout-numérique, CAN au niveau des pixels présentent les mérites évidents sur le bruit, la vitesse, la zone sensible et la consommation d’énergie. Un prototype de capteur, appelé MIMADC, a été implémenté par un processus de 0.18 μm CIS (CMOS Image Sensor). L’objectif de ce capteur est de vérifier la faisabilité du CPS intégré avec les CAN au niveau des pixels. Trois matrices sont incluses dans ce prototype, mais avec deux types différents de CAN au niveau de pixel: une avec des CAN à registre à approximations successives (SAR), et les deux autres avec des CAN à une seule pente (Single-Slope, SS) CAN. Toutes les trois possédant les pixels de la même taille de 35×35 μm2 et une résolution de 3-bit. Dans ce texte, des analyses théoriques et le prototype sont présentés, ainsi que la conception détaille des circuitsThis thesis presents the development of CMOS pixel sensors (CPS) integrated with pixel-level ADCs for the outer layers of the ILD (International Large Detector) vertex detector. Driven by physics in the ILC (International Linear Collider), an unprecedented precision is required for the detectors. The priority of the sensors mounted on the outer layers is low power consumption due to the large coverage ratio of the sensitive area (~90%) in the vertex detector. The CPS integrated with ADCs is a promising candidate for this application. The architecture of column-level ADCs, exists but do not provide an optimized performance in terms of noise and power consumption. The concept of pixel-level ADCs has been proposed. Benefiting from the all-digital pixel outputs, pixel-level ADCs exhibit the obvious merits on noise, speed, insensitive area, and power consumption. In this thesis, a prototype sensor, called MIMADC, has been implemented by a 0.18 μm CIS (CMOS Image Sensor) process. The target of this sensor is to verify the feasibility of the CPS integrated with pixel-level ADCs. Three matrices are included in this prototype but with two different types of pixel-level ADCs: one with successive approximation register (SAR) ADCs, and the other two with single-slope (SS) ADCs. All of them feature a same pixel size of 35×35 μm2 and a resolution of 3-bit. In this thesis, the prototype is presented for both theoretical analyses and circuit designs. The test results of the prototype are also presented
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Schnoor, Ulrike. "Vector Boson Scattering and Electroweak Production of Two Like-Charge W Bosons and Two Jets at the Current and Future ATLAS Detector." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-164546.
Full textAbstract:
The scattering of electroweak gauge bosons is closely connected to the electroweak gauge symmetry and its spontaneous breaking through the Brout-Englert-Higgs mechanism. Since it contains triple and quartic gauge boson vertices, the measurement of this scattering process allows to probe the self-interactions of weak bosons. The contribution of the Higgs boson to the weak boson scattering amplitude ensures unitarity of the scattering matrix. Therefore, the scattering of massive electroweak gauge bosons is sensitive to deviations from the Standard Model prescription of the electroweak interaction and of the properties of the Higgs boson.
At the Large Hadron Collider (LHC), the scattering of massive electroweak gauge bosons is accessible through the measurement of purely electroweak production of two jets and two gauge bosons. No such process has been observed before. Being the channel with the least amount of background from QCD-mediated production of the same final state, the most promising channel for the first measurement of a process containing massive electroweak gauge boson scattering is the one with two like-charge W bosons and two jets in the final state. This thesis presents the first measurement of electroweak production of two jets and two identically charged W bosons, which yields the first observation of a process with contributions from quartic gauge interactions of massive electroweak gauge bosons.
An overview of the most important issues in Monte Carlo simulation of vector boson scattering processes with current Monte Carlo generators is given in this work. The measurement of the final state of two jets and two leptonically decaying same-charge W bosons is conducted based on proton-proton collision data with a center-of-mass energy of √s = 8 TeV, taken in 2012 with the ATLAS experiment at the LHC. The cross section of electroweak production of two jets and two like-charge W bosons is measured with a significance of 3.6 standard deviations to be σ(W± W±jj−EW[fiducial]) = 1.3 ± 0.4(stat.) ± 0.2(syst.) fb in a fiducial phase space region selected to enhance the contribution from W W scattering. The measurement is compatible with the Standard Model prediction of σ(W±W± jj−EW[fiducial]) = 0.95 ± 0.06 fb. Based on this measurement, limits on anomalous quartic gauge couplings are derived. The effect of anomalous quartic gauge couplings is simulated within the framework of an effective chiral Lagrangian unitarized with the K-matrix method. The limits for the anomalous coupling parameters α4 and α5 are found to be −0.14 < α4 < 0.16 and −0.23 < α5 < 0.24 at 95 % confidence level.
Furthermore, the prospects for the measurement of the electroweak production of two same-charge W bosons and two jets within the Standard Model and with additional doubly charged resonances after the upgrade of the ATLAS detector and the LHC are investigated. For a high-luminosity LHC with a center-of-mass energy of √s = 14 TeV, the significance of the measurement with an integrated luminosity of 3000 fb^−1 is estimated to be 18.7 standard deviations. It can be improved by 30 % by extending the inner tracking detector of the atlas experiment up to an absolute pseudorapidity of |η| = 4.0.
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Bhat, Siddharth. "Design and characterization in depleted CMOS technology for particle physics pixel detector." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0267.
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L’expérience ATLAS commencera à fonctionner avec l’accélérateur LHC à hauteluminosité (HL-LHC) en 2026 pour augmenter la probabilité de nouvelles découvertes. La technologie du détecteur de pixels monolithiques en "depleted" CMOS a été une des options envisagées pour la couche externe du détecteur pixel d’ATLAS mis a niveau et est une technologie à fort potentiel pour les futurs détecteurs a pixels. Dans cette thèse, plusieurs prototypes ont été développés utilisant différentes technologies CMOS appauvries, par exemple, LFoundry (LF) 150 nm, TowerJazz (TJ) à 180 nm et Austriamicrosystems AG (AMS) à 180 nm. Dans un environnement à haute énergie, tel que HL-LHC, les événements uniques (SEU), qui deviennent un sujet de préoccupation pour le bon fonctionnement des circuits. Plusieurs puces de test dans les technologies AMS, TowerJazz et LFoundry avec différentes structures tolérantes au SEU ont été prototypées et testées. Un schéma d’alimentation alternatif appelé schéma d’alimentation série est prévu pour le futur détecteur Inner Tracker (ITk) de l’expérience ATLAS. Pour répondre aux exigences de l’expérience ATLAS concernant l’environnement d’une couche pixélisée dans un environnement de collisionneur à rayonnement élevé, de nouveaux développements avec des capteurs "depleted" CMOS ont été développés dans le régulateur Shunt-LDO et la polarisation de capteur conçus dans la technologie d’imagerie CMOS TowerJazz 0,18 um modifiée. Dans le processus TowerJazz modifié, deux niveaux de tension différents sont utilisés pour l'épuisement du capteur. Polarisation les tensions sont générées à l'aide d'un circuit de pompe à charge négativeThe ATLAS experiment will start operating at the High Luminosity LHC accelerator (HL-LHC) in 2026 to increase the probability of new discoveries. Depleted CMOS monolithic pixel detector technology has been one of the options considered for the outer layer of an upgraded ATLAS pixel detector and is a high potential technology for future pixel detectors. In this thesis, several prototypes have been developed using different depleted CMOS technologies, for instance, LFoundry (LF) 150 nm, TowerJazz (TJ) 180 nm and austriamicrosystems AG (AMS) 180 nm. In a high-energy environment like HL-LHC, Single Event Upsets (SEU), which become of concern for reliable circuit operation. Several test-chips in AMS, TowerJazz and LFoundry technologies with different SEU tolerant structures have been prototyped and tested. The SEU tolerant structures were designed with appropriate electronics simulations using Computer Aided Design (CAD) tools in order to study the sensitivity of injected charge to upset a memory state. An alternative powering scheme named Serial Powering scheme is foreseen for the future Inner Tracker (ITk) detector of the ATLAS experiment. To meet the requirements ofthe ATLAS experiment to the environment of a pixelated layer in a high radiation collider environment, new developments with depleted CMOS sensors have been made in Shunt-LDO regulator and sensor biasing which are designed in modified TowerJazz 180 nm CMOS imaging technology. In the TowerJazz modified process, two different voltage levels are used for the purpose of sensor depletion. The bias voltages are generated by using a negative charge pump circuit
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Ouamara, Hamid. "Comparaison de la micro-tomodensitométrie par comptage de photons et par intégration de charges avec le dispositif d'irradiation PIXSCAN." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4004/document.
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L'approche développée par l'équipe imXgam du CPPM a consisté à adapter la technologie des pixels hybrides XPAD à l'imagerie biomédicale. C'est dans cette optique qu'un micro-tomodensitomètre PIXSCAN II basé sur la nouvelle génération de détecteurs à pixels hybrides appelés XPAD3 a été développé. Ce travail de thèse décrit la démarche engagée pour évaluer l'apport de la technologie à pixels hybrides en tomodensitométrie par rayons X en termes de contraste et de dose et pour explorer de nouvelles possibilités d'imagerie biomédicale à faible dose. L'évaluation des performances ainsi que la validation des résultats obtenus avec les données acquises avec le détecteur XPAD3 ont été comparées aux résultats obtenus avec la caméra CCD DALSA XR-4 similaire aux détecteurs utilisés dans la plupart des micro-TDM usuels. Le détecteur XPAD3 permet d'obtenir des images reconstruites d'une qualité satisfaisante et proche de celle des images de la caméra DALSA XR-4, mais avec une meilleure résolution spatiale. A faible dose, les images du détecteur XPAD3 sont de meilleure qualité que celles de la caméra CCD. Du point de vue de l'instrumentation, ce projet a prouvé le bon fonctionnement du dispositif PIXSCAN II pour la souris. Nous avons pu reproduire une qualité d'image semblable à celle obtenue avec un détecteur à intégration de charges de type caméra CCD. Pour améliorer les performances du détecteur XPAD3, il va falloir optimiser la stabilité des seuils et avoir des courbes de réponses des pixels en fonction de l'énergie assez homogènes en utilisant un capteur plus dense comme le CdTe par exempleThe pathway that has been followed by the imXgam team at CPPM was to adapt the hybrid pixel technology XPAD to biomedical imaging. It is in this context that the micro-CT PIXSCAN II based on the new generation of hybrid pixel detectors called XPAD3 has been developed. This thesis describes the process undertaken to assess the contribution of the hybrid pixel technology in X-ray computed tomography in terms of contrast and dose and to explore new opportunities for biomedical imaging at low doses. Performance evaluation as well as the validation of the results obtained with data acquired with the detector XPAD3 were compared to results obtained with the CCD camera DALSA XR-4 similar to detectors used in most conventional micro-CT systems. The detector XPAD3 allows to obtain reconstruced images of satisfactory quality close to that of images from the DALSA XR-4 camera, but with a better spatial resolution. At low doses, the images from the detector XPAD3 have a better quality that is those from CCD camera. From an instrumentation point of view, this project demonstrated the proper erations of the device PIXSCAN II for mouse imaging. We were able to reproduce an image quality similar to that obtained with a charge integration detector such as a CCD camera. To improve the performance of the detector XPAD3, we will have to optimize the stability of the thresholds and in order to obtain more homogeneous response curves of the pixels as a function as energy by using a denser sensor such as CdTe
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Cheng, Shanfeng. "Design of CMOS integrated phase-locked loops for multi-gigabits serial data links." Texas A&M University, 2006. http://hdl.handle.net/1969.1/4954.
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High-speed serial data links are quickly gaining in popularity and replacing the
conventional parallel data links in recent years when the data rate of communication
exceeds one gigabits per second. Compared with parallel data links, serial data links are
able to achieve higher data rate and longer transfer distance. This dissertation is focused on
the design of CMOS integrated phase-locked loops (PLLs) and relevant building blocks
used in multi-gigabits serial data link transceivers.
Firstly, binary phase-locked loops (BPLLs, i.e., PLLs based on binary phase detectors) are
modeled and analyzed. The steady-state behavior of BPLLs is derived with combined
discrete-time and continuous-time analysis. The jitter performance characteristics of BPLLs
are analyzed. Secondly, a 10 Gbps clock and data recovery (CDR) chip for SONET OC-
192, the mainstream standard for optical serial data links, is presented. The CDR is based
on a novel referenceless dual-loop half-rate architecture. It includes a binary phase-locked
loop based on a quad-level phase detector and a linear frequency-locked loop based on a
linear frequency detector. The proposed architecture enables the CDR to achieve large locking range and small jitter generation at the same time. The prototype is implemented in
0.18 üm CMOS technology and consumes 250 mW under 1.8 V supply. The jitter
generation is 0.5 ps-rms and 4.8 ps-pp. The jitter peaking and jitter tolerance performance
exceeds the specifications defined by SONET OC-192 standard. Thirdly, a fully-differential
divide-by-eight injection-locked frequency divider with low power dissipation is presented.
The frequency divider consists of a four-stage ring of CML (current mode logic) latches. It
has a maximum operating frequency of 18 GHz. The ratio of locking range over center
frequency is up to 50%. The prototype chip is implemented in 0.18 üm CMOS technology
and consumes 3.6 mW under 1.8 V supply. Lastly, the design and optimization techniques
of fully differential charge pumps are discussed. Techniques are proposed to minimize the
nonidealities associated with a fully differential charge pump, including differential
mismatch, output current variation, low-speed glitches and high-speed glitches. The
performance improvement brought by the techniques is verified with simulations of
schematics designed in 0.35 üm CMOS technology.
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Amin, Farooq ul. "On the Design of an Analog Front-End for an X-Ray Detector." Thesis, Linköping University, Department of Electrical Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-21395.
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Rapid development in CMOS technology has resulted in its suitability for the implementation of readout front-end systems in terms of high integration density, and low power consumption yet at the same time posing many challenges for analog circuits design like readout front-end. One of the significant challenges is the low noise design for high speed front-end systems, while at the same time minimizing the power consumption as much as possible.
A high speed, low noise, low power, and programmable readout front-end system is designed and implemented for an X-ray detector in CMOS 0.18 m technology in this thesis work. The front-end system has a peaking time of 10 ns, which is the highest speed ever reported in the published work. The front-end system is designed to achieve low noise in terms of ENC, and a low power consumption of 2.9 mW. The detector capacitance is the most dominating parameter to low noise, which in turn is directly related to the power consumption. In this thesis work an ENC of 435 electrons is achieved for a detector capacitance of 5 pF and an ENC of 320 electrons for a detector capacitance of 3 pF. Based on the comparison to related published work, a performance improvement of at least two times is achieved taking peaking time, power, ENC, and detector capacitance all into consideration. The output pulse after amplification has peak amplitude of 300 mV for a maximum injected charge of 40000 electrons from the detector.
The readout front-end system noise performance is strongly dependent on the input MOSFET type, size, and biasing. In this work a PMOS has been selected and optimized as the input device due to its smaller 1/f noise and high gain as compare to NMOS when biased at same currents. The architecture designed in this work consists of a folded cascode CSA with extra cascode in first stage, a pole-zero cancellation circuit to eliminate undershoot, a shaper amplifier, and integrators using Gm-C filter technique. All of these components are optimized for low power while meeting the noise requirements. The whole front-end system is programmed for peaking times of 10, 20, and 40 ns. The programmability is achieved by switching different capacitors and resistors values for all the poles and zeros in the front-end, and by switching parallel transconductance in the Gm-C filters. Finally fine tuning of all the capacitance, resistance, and transconductance values is done to achieve required performance.
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Paredes, Hernández Daniela. "Search for New Physics in events with 4 top quarks in the ATLAS detector at the LHC." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2013. http://tel.archives-ouvertes.fr/tel-00921146.
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This thesis presents the search for New Physics in events with four top quarks using the data collected in proton-proton collisions by the ATLAS experiment at the LHC. The dataset corresponds to the one taken during all 2011 at √s = 7 TeV and a part of 2012 at √s = 8 TeV. The analysis focuses on a final state with two leptons (electrons and muons) with the same electric charge. This signature is experimentally favored since the presence of two same-sign leptons in the final state allows to reduce the background coming from Standard Model (SM) processes. The results are interpreted in the context of a low energy effective field theory, which assumes that New Physics at low energy can manifest itself as a four right-handed top contact interaction. In this context, this analysis allows testing a class of beyond-the-SM (BSM) theories which at low energy can manifest in this way. Backgrounds to this search have been estimated using simulated samples and data-driven techniques. Different sources of systematic uncertainties have been also considered. The final selection of events has been optimized by aiming at minimizing the expected upper limit on the four tops production cross-section in case of no signal events found. The signal region is then analyzed by looking for an excess of events with respect to the predicted background. No excess of events has been observed, and the observed upper limit on the four tops production cross-section has been computed. This limit is then translated to an upper limit on the coupling strength C=2 of the model. An upper limit on the four tops production cross-section in the SM has been also computed in the analysis performed at √s = 8 TeV. In addition to the physics analysis of the four tops signal, some studies about the LASER calibration system of the ATLAS Tile calorimeter are presented. In particular, they are related to the photodiodes system used to measure the intensity of the laser light in the LASER system.
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Foerster, Nadine [Verfasser], and J. [Akademischer Betreuer] Blümer. "Detector optimization based on studies of charge migration in the high purity germanium crystals of the EDELWEISS dark matter experiment / Nadine Foerster ; Betreuer: J. Blümer." Karlsruhe : KIT-Bibliothek, 2017. http://d-nb.info/1129258793/34.
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Zhou, Yifan, Dániel Apai, Ben W. P. Lew, and Glenn Schneider. "A Physical Model-based Correction for Charge Traps in the Hubble Space Telescope’s Wide Field Camera 3 Near-IR Detector and Its Applications to Transiting Exoplanets and Brown Dwarfs." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/625388.
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The Hubble Space Telescope Wide Field Camera 3 (WFC3) near-IR channel is extensively used in time-resolved observations, especially for transiting exoplanet spectroscopy as well as. brown dwarf and directly imaged exoplanet rotational phase mapping. The ramp effect is the dominant source of systematics in the WFC3 for time-resolved observations, which limits its photometric precision. Current mitigation strategies are based on empirical fits and require additional orbits to help the telescope reach a thermal equilibrium. We show that the ramp-effect profiles can be explained and corrected with high fidelity using charge trapping theories. We also present a model for this process that can be used to predict and to correct charge trap systematics. Our model is based on a very small number of parameters that are intrinsic to the detector. We find that these parameters are very stable between the different data sets, and we provide best-fit values. Our model is tested with more than 120 orbits (similar to 40 visits) of WFC3 observations. and is proved to be able to provide near photon noise limited corrections for observations made with both staring and scanning modes of transiting exoplanets as well as for starting-mode observations of brown dwarfs. After our model correction, the light curve of the first orbit in each visit has the same photometric precision as subsequent orbits, so data from the first orbit no longer need. to. be discarded. Near-IR arrays with the same physical characteristics (e.g., JWST/NIRCam) may also benefit from the extension of this model if similar systematic profiles are observed.
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Czirr, Hendrik [Verfasser]. "Measurement of the charge asymmetry in the top-quark dilepton decay channel in pp collision data at √s = 7 TeV using the ATLAS detector / Hendrik Czirr." Siegen : Universitätsbibliothek der Universität Siegen, 2014. http://d-nb.info/1061174999/34.
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Habib, Amr. "Détecteurs radiologiques grande surface, multi-énergie." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT055.
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L'objectif de la thèse est de proposer une solution pour un circuit intégré matriciel pour l'imagerie de rayons X fonctionnant, soit en mode spectrométrique où l'énergie de chaque photon X est mesurée, soit en mode d'intégration de charges où l'énergie totale déposée par les rayons X pendant une image est mesurée, la solution devant être à terme compatible avec un détecteur de grande surface typiquement de 20 cm x 20 cm. Un circuit de test (ASIC), ‘Sphinx' de 20 x 20 pixels au pas de 200 µm x 200 µm, en technologie CMOS 0.13 µm a été conçu pour servir de preuve du concept proposé. L'architecture de pixel retenue permet la quantification de la charge incidente par des paquets de contre-charges aussi bas que 100 électrons, ces contre-charges étant comptabilisées, soit pour chaque photon X (mode spectrométrique), soit pour la totalité des photons détectés pendant une image (mode intégration). Les premières mesures de caractérisation prouvent la validité du concept avec de bonnes performances en termes de consommation, bruit et linéarité. Une partie des pixels est dédiée à la détection directe des rayons X, ceux-ci étant alors convertis en charges électriques dans un semi-conducteur, tel que CdZnTe par exemple, lequel semiconducteur est couplé pixel à pixel à l'ASIC. Une autre partie des pixels est dédiée à la détection indirecte des rayons X, ceux-ci étant alors convertis en photons visibles dans une couche scintillatrice, telle CsI : Tl par exemple, et chaque pixel de l'ASIC possédant alors une photodiode. Pour ce dernier mode, de nouvelles formes de photodiodes rapides et peu capacitives ont de plus été conçues, simulées, et fabriquées en technologie CMOS 0.13 µm sur un autre ASIC. Enfin, la thèse se conclut en proposant des idées d'amélioration de performances à réaliser potentiellement dans un futur prototypeThe objective of the thesis is to propose a solution for a 2D integrated circuit X-ray imager working, either in spectrometric mode where each X photon energy is measured, or in charge integration mode where the total energy deposited by X-ray during an image is measured, the solution being compatible with large area detectors typically of 20 cm x 20 cm. A proof of concept prototype ASIC 'Sphinx' was designed and fabricated in CMOS 0.13 µm technology; the ASIC being formed of a matrix of 20 x 20 pixels with a 200 µm pixel pitch. The designed architecture allows the quantification of the incoming charge through the use of counter-charge packets as low as 100 electrons. The injected packets are counted for each X photon (in the spectrometric photon counting mode), or for all charges integrated during the image period (in charge integration mode). First characterization measurements prove the validity of the concept with good performance in terms of power consumption, noise, and linearity. A first part of the ASIC is dedicated to X-ray direct detection where a semiconductor, e.g. CdZnTe, hybridized to the ASIC's pixels converts X-photons to electrical charge. Another part of the ASIC is dedicated indirect X-ray detection where a scintillator, e.g. CsI:Tl, is used to convert X-photons to visible photons which are then detected by in-pixel photodiodes. For the latter mode, new forms of photodiodes characterized by fast detection and low capacity were designed, simulated, and fabricated in CMOS 0.13 µm technology on a different ASIC. Finally, the thesis concludes with proposing performance enhancing ideas to be potentially implemented in a future prototype
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Ginsz, Michaël. "Characterization of high-purity, multi-segmented germanium detectors." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAE047/document.
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L’apparition de la segmentation électrique des détecteurs au GeHP et de l’électronique numérique a ouvert la voie à des applications prometteuses, telles que le tracking γ, l’imagerie γ ou la mesure bas bruit de fond, pour lesquelles une connaissance fine de la réponse du détecteur est un atout. L’IPHC a développé une table de scan utilisant un faisceau collimaté, qui sonde la réponse d’un détecteur dans tout son volume en fonction de la localisation de l’interaction. Elle est conçue pour utiliser une technique innovante de scan 3D, le Pulse Shape Comparison Scan, qui a été d’abord simulée afin de démontrer son efficacité. Un détecteur AGATA a été scanné de manière approfondie. Des scan 2D classiques ont permis, entre autres, de mettre en évidence des effets locaux de modification de la collection des charges, liés à la segmentation. Pour la première fois, une base de données 3D, complète, de formes d’impulsions fonction de la position d’interaction a été établie. Elle permettra notamment d’améliorer les performances du spectromètre AGATARecent developments of electrical segmentation of HPGe detectors, coupled with digital electronics have led to promising applications such as γ-ray tracking, γ-ray imaging or low-background measurements which will benefit from a fine knowledge of the detector response. The IPHC has developed a new scanning table which uses a collimated γ-ray beam to investigate the detector response as a function of the location of the γ-ray interaction. It is designed to use the Pulse Shape Comparison Scan technique, which has been simulated in order to prove its efficiency. An AGATA detector has been thoroughly scanned. 2D classical scans brought out, for example, local charge collection modification effects such as charge sharing, due to the segmentation. For the first time, a 3D, complete pulse-shape database has been established. It will especially allow to improve the overall AGATA array performances
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Schomakers, Christian [Verfasser], Lutz Werner [Akademischer Betreuer] Feld, and Thomas [Akademischer Betreuer] Hebbeker. "Search for supersymmetry in opposite-charge, same-flavor dilepton events recorded with the CMS detector at √s = 13TeV in 2016 data / Christian Schomakers ; Lutz Werner Feld, Thomas Hebbeker." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1171993242/34.
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Betancourt, Christopher [Verfasser], and Karl [Akademischer Betreuer] Jakobs. "Charge multiplication detectors for use in the HL-LHC and measurement of the production cross-section in pp collisions of a W boson in association with a charm quark at sqrt (s) = 8 TeV with the ATLAS detector." Freiburg : Universität, 2016. http://d-nb.info/1122830777/34.
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Jones, Sarah, and Sarah Jones. "Searching for Vector-Like Quarks Using 36.1 fb^{-1} Of Proton-Proton Collisions Decaying to Same-Charge Dileptons and Trileptons + b-jets at √s = 13 TeV with The ATLAS Detector." Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/626353.
Full textAbstract:
Since the discovery of the Higgs boson in 2012, the search for new physics beyond
the Standard Model has been greatly intensified. At the CERN Large Hadron Collider
(LHC), ATLAS searches for new physics entail looking for new particles by colliding
protons together. Presented here is a search for a new form of quark matter called
Vector-like Quarks (VLQ), which are hypothetical particles that are expected to have
mass around a few TeV. VLQ can come in a variety of forms and can couple to
their Standard Model (SM) quark counterparts, particularly to the third generation.
They are necessary in several beyond the SM theories in order to solve the hierarchy
problem. This search uses 36.1 fb−1of proton-proton collision data collected with the
ATLAS detector at the LHC from August 2015 to October 2016. Only events with two
leptons of the same charge, or three leptons, plus b-jets and high missing transverse
energy are considered in the main analysis. This signature is rarely produced in the
SM, which means the backgrounds in this analysis are relatively low. This analysis
is sensitive to specific predicted decay modes from pair production of an up-type
VLQ with a charge of +2/3, T, an up-type VLQ with a charge of +5/3, T5/3, and
a down-type quark with a charge of −1/3, B, as well as single production of T5/3.
There is another theorized VLQ that this analysis is not sensitive to: B−4/3, due
to its primary decay mode, which is unable to produce the final-state signature of
interest. The results from this analysis suggest only a slight deviation of data from
SM backgrounds reaching as high as 1.89σ, which does not indicate evidence for
VLQ. A mostly frequentist statistical technique, called the CLS Method, is used to
interpret the data and set limits on the T, B, and T5/3 signal models. Using this
method, exclusion limits are set at the 95% confidence level, effectively excluding T
mass below 0.98 TeV, T5/3 mass below 1.2 TeV, and B mass below 1.0 TeV, assuming
singlet branching ratios. Also, branching ratio independent limits are set on the T
and B VLQ.
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Schnoor, Ulrike [Verfasser], Michael [Akademischer Betreuer] Kobel, and Sabine [Akademischer Betreuer] Lammers. "Vector Boson Scattering and Electroweak Production of Two Like-Charge W Bosons and Two Jets at the Current and Future ATLAS Detector / Ulrike Schnoor. Gutachter: Michael Kobel ; Sabine Lammers." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://d-nb.info/1071785591/34.
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Kohn, Fabian [Verfasser], Arnulf [Akademischer Betreuer] Quadt, and Carsten [Akademischer Betreuer] Hensel. "Measurement of the charge asymmetry in top quark pair production in in pp collision data at √s = 7 TeV using the ATLAS detector / Fabian Kohn. Gutachter: Arnulf Quadt ; Carsten Hensel. Betreuer: Arnulf Quadt." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2012. http://d-nb.info/1043610634/34.
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