155 research outputs found

    Sympathetic Cooling of a Single Individually-Trapped Proton in a Cryogenic Penning Trap

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    A method to prepare arbitrary stored ions with low energy in the mK range would improve many high-precision Penning trap experiments and is essential for high-precision measurements of the antiproton and proton g-factors. In this thesis, we investigate sympathetic cooling of a single individually-trapped proton by laser-cooled 9Be+ ions stored in a separate trap. Both ions are coupled by image currents induced in a common electrode and the coupling is enhanced by a connected cryogenic superconducting radio-frequency RLC oscillator. The image-current based coupling makes the technique applicable to arbitrary ions. We describe the new experimental setup, based on a significant modification of the previous proton g-factor experiment, and the installation and optimization of new image-current detectors. We further describe the development and characterization of a single-photon sensitive fluorescence detection system based on silicon photomultipliers integrated into the cryogenic Penning trap. We demonstrate laser-cooling of the 9Be+ ions and measure their temperature to 1.1(2) mK using fluorescence detection. The simultaneous detection of fluorescence photons and image currents of laser-cooled 9Be+ ions enables a measurement of the laser-induced damping. We further demonstrate sympathetic cooling of the axial mode of a single proton to 2.6(2.5) K, limited by the applied temperature measurement method. With a newly developed temperature measurement trap, we improve this value to 160(30) mK, almost two orders of magnitude below the environment temperature. Finally, we argue that the technique can be optimized to reach temperatures in the low double-digit mK range, which would enable a future generation of antiproton and proton g-factor measurements with an order of magnitude improved precision. For other high-precision Penning trap experiments, the method will be an attractive tool to prepare arbitrary ions for measurement

    The provenance and thermal histories of the Carboniferous Midland Valley of Scotland

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    Sedimentary basins are an important geological archive as they contain a wealth of information about the regions palaeogeographical setting, thermal evolution, and post depositional history, which are critical to many geological applications. However, establishing the source(s) of the sedimentary material stored within a basin, can be complicated by the refractory nature of some minerals often used as proxies for sediment provenance, meaning that a recycled component may be present and difficult to recognise. Thermal and burial history reconstructions based on the maturation of organic matter (vitrinite reflectance, VR) has been applied widely by the hydrocarbon industry to great success. However, due to the techniques inability to supply a quantification on time, its application in regions that lack post depositional constraints can lead to differing interpretations. In this thesis two geochronometers (zircon and apatite U-Pb geochronology) and one thermochronometer (apatite fission track, AFT) have been applied to the Carboniferous sedimentary strata of the central and eastern regions of the Midland Valley of Scotland. The aim of which is to provide a better understanding of the evolution of post-Caledonian sediment source(s) and pathways and to better constrain the post-Carboniferous thermal histories of the Midland Valley. This will reduce the geological uncertainties associated with the region, which is vital for Scotland to meet its future low carbon geo-energy commitments. A multi-proxy approach, applying U-Pb geochronology to detrital zircon and apatite has been utilised to investigate and constrain the provenance of the clastic material in Viséan to Westphalian B, Carboniferous sandstones of the Midland Valley of Scotland. The results of this provenance data clearly show three distinct sources for the sandstones: 1) Laurentian associated rocks (~900-2000 and ~2500-3100 Ma), 2) Caledonian orogeny associated rocks (395-475 Ma), and 3) Carboniferous volcanic associated rocks (~330-350 Ma). Applying U-Pb geochronology to both zircon and apatite from the same sandstone has allowed for the identification of recycled components, indicating that not all U-Pb age populations have been derived directly from their original source. Detrital zircon UPb age peaks that align with the Grenvillian (900-1200 Ma), Pinwarian (1450-1510 Ma), Labradorian (1600-1700 Ma), and Lewisian (2500-3100 Ma) orogenic events, lack equivalent apatite U-Pb counterparts. This suggests that Laurentian associated populations have been derived through the recycling of existing sedimentary and metasedimentary lithologies from the Devonian Old Red Sandstone, Grampian terrane, and Southern Uplands. Samples with complementary prominent Caledonian orogeny associated zircon and apatite U-Pb age peaks, are likely to be derived from first cycle sources from north of the Midland Valley, while Carboniferous ages are most likely derived from volcanic sources within the region. Spatial and temporal variation in the sample detrital spectra, indicates the provenance source did not remain constant over time. Early-mid Viséan (ArundianAsbian) U-Pb zircon samples are dominated by Proterozoic and Archean, Laurentian associated ages and lack a significant Caledonian peak, indicating recycling of Devonian Old Red Sandstone, Grampian terrane, and Southern Uplands dominated the sediment supply. U Pb apatite samples from the same time are dominated by a Caledonian peak suggesting either a very minor Caledonian associated source was actively supplying a limited amount of sediment or recycling of apatite through existing sedimentary lithologies is possible, as previous investigations have shown late Devonian Old Red Sandstone to be lacking in Caledonian aged U-Pb zircon. Late Viséan (Brigantian) samples in the eastern Midland Valley of Scotland have a marked increase in Palaeozoic Caledonian associated zircon ages, indicating the source region now included first cycle Caledonian associate rocks, although Laurentian associated components still dominate the spectra. A Brigantian sample collected to the west of the Bathgate Hills Volcanic Formation, located towards the centre of the study area, still shows a paucity in Caledonian related zircon ages, suggesting the volcanic high was a barrier or at least hindered sediment from the northeast being deposited across the region. Carboniferous peaks present in Brigantian zircon and apatite samples indicate the volcanic highs were also local sediment sources. A major change in sediment provenance occurs during the early Namurian (Pendleian) evidenced by the reversal in the dominant source signal, with Laurentian associated ages now relatively insignificant compared to Palaeozoic peaks, indicating first cycle Caledonian associated rocks now dominated the source area. A similar signal is recorded in Carboniferous strata in the Millstone Grit Formation in the Pennine Basin, attributed to a regional source to the north supplied via the Pennine delta. This distal source was also likely supplying material into the Midland Valley as well as proximal sources from Scottish Caledonian rocks, which combined to drown out the recycled component. Caledonian ages continue to dominate the Midland Valley samples in the Westphalian, contrary to Carboniferous basins to the south, which experience a reduction in the influence from the northern source during the Westphalian. Sources that dominated basins to the south were most likely prevented from entering the Midland Valley of Scotland by the Southern Upland high, which allowed the Caledonian sources to prevail. Undertaking detrital thermochronology is challenging due to the low yield of accessory minerals in some sedimentary rocks. However, results show AFT ages from the Midland Valley of Scotland reflect the geological structure of the region during the Carboniferous, with oldest ages located within the syncline cores and on structural highs. A complex series of forward and inverse modelling of individual and multi-sample profiles, combining outcrop and borehole samples, suggests the thermal histories can be sub-divided into three episodes: 1) Carboniferous Permian heating, 2) PermianMesozoic Cooling, and 3) Cenozoic cooling. . Inverse models also suggest initial heating was under the influence of an elevated geothermal gradient, supported by Carboniferous volcanic activity. These episodes are similar to those reported in other thermochronology investigations for onshore Scotland and show a contrast to those reported offshore, suggesting the onshore region was cooling as a coherent block from post Carboniferous times. Though the general trend observed in profile models is one of cooling through the Mesozoic, indicating an absence of significant burial under continued successions, some individual samples display an element of late Mesozoic reheating, which may be attributable to the Late Cretaceous transgression. The final Cenozoic cooling pulse, evident across the region, has been recognised in numerous investigations and has been attributed to processes associated with the emplacement of the proto-Icelandic plume or far field stresses related to compressional forces associated with the opening of the North Atlantic Ocean and Alpine collision. However, the temperature sensitivity of AFT is not enough to resolve this part of the thermal history. The results reported in this thesis reveal that the provenance of the Carboniferous sedimentary strata of the Midland Valley of Scotland did not remain constant through time and that post burial thermal maximum was attained following Carboniferous burial under an elevated geothermal gradient which was followed by episodes of cooling. These findings have important implications for assessing the future geo-energy potential within the Midland Valley of Scotland

    Diagnóstico precoz de secreción autónoma de cortisol en pacientes con incidentalomas adrenales “no funcionantes”

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    Los incidentalomas suprarrenales (IS) son uno de los motivos de consulta más frecuentes en Endocrinología. En todo paciente con un IS de nuevo diagnóstico se deben valorar dos aspectos fundamentales: a) su naturaleza benigna o maligna y b) su funcionalidad. Sin embargo, a pesar de que la secreción autónoma de cortisol (SAC) está presente en hasta un 50% de los IS y se asocia a un aumento de la morbimortalidad, las pruebas hormonales de las que disponemos en la actualidad para establecer su diagnóstico presentan múltiples limitaciones. Por otra parte, incluso en IS aparentemente no funcionantes se ha observado un mayor riesgo cardio-metabólico y de mortalidad que en la población general. Este mayor riesgo podría estar justificado por la presencia de alteraciones incipientes en el metabolismo del cortisol no detectadas con las pruebas clásicas y que, con el tiempo, pueden progresar hasta hacerse detectables. Esto conlleva la necesidad de reevaluar periódicamente la capacidad autónoma para secretar cortisol en los pacientes con IS no funcionantes (ISNF). Por tanto, sería deseable identificar marcadores que permitan determinar, de forma más precoz y precisa, alteraciones en la secreción de cortisol que puedan tener una posible repercusión cardio-metabólica y/o marcadores clínicos, radiológicos y/o bioquímicos asociados a un mayor riesgo de desarrollar SAC en pacientes con ISNF. En nuestro estudio hemos encontrado que ciertas características clínicas, bioquímicas y radiológicas permiten estratificar el riesgo de desarrollar SAC en ISNF. Encontramos que el mejor modelo predictivo de desarrollo de SAC a lo largo del seguimiento combinó las variables edad, nivel de cortisol sérico tras el test de supresión con 1 mg de dexametasona (TSD) y la bilateralidad de los IS en el momento del diagnóstico. Los pacientes con ISNF con el riesgo más bajo de desarrollar SAC a lo largo del seguimiento fueron aquellos de menos de 50 años con valores de cortisol post-TS

    Analysis and optimization of a debug post-silicon hardware architecture

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    The goal of this thesis is to analyze the post-silicon validation hardware infrastructure implemented on multicore systems taking as an example Esperanto Technologies SoC, which has thousands of RISC-V processors and targets specific software applications. Then, based on the conclusions of the analysis, the project proposes a new post-silicon debug architecture that can fit on any System on-Chip without depending on its target application or complexity and that optimizes the options available on the market for multicore systems

    Readout Electronics for the Upgraded ITS Detector in the ALICE Experiment

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    ALICE is undergoing upgrades during the Long Shutdown (LS) 2 of the LHC to improve its performance and capabilities, and to prepare the experiment for the increases in luminosity provided by the LHC in Run 3 and Run 4. One of the most extensive upgrades of the experiment (and the topic of this thesis) is the replacement of the Inner Tracking System (ITS) in its entirety with a new and upgraded system. The new ITS consists exclusively of pixel sensors organized in seven cylindrical layers, and offers significantly improved tracking capabilities at higher interaction rates. And in contrast to the previous system, which would only trigger on a subset of the available events that were deemed “interesting”, the upgraded ITS will capture all events; either in a triggered mode using minimum-bias triggers, or in a “trigger-less” continuous mode where event data is continuously read out. The key component of the upgrade is a novel pixel sensor chip, the ALPIDE, which was developed at CERN specifically for the ALICE ITS upgrade. The seven layers of the ITS is assembled from sub-assemblies of sensor chips referred to as staves, and the entire detector consists of 24 120 chips in total. The staves come in three different configurations; they range from 9 chips per stave for the innermost layers, and up to 196 chips per stave in the outer layers. The number of control and data links, as well as the bit-rate of the data links, differs widely between the staves as well. Data readout from the high-speed copper links of the detector requires dedicated readout electronics in the vicinity of the detector. The core component of this system is the FPGA-based Readout Unit (RU). It facilitates the readout of the data links and transfer data to the experiment’s server farms via optical links; provides control, configuration and monitoring of the sensor chips using the same optical links, as well as over CAN-bus for redundancy; distributes trigger signals to the sensor, either by forwarding the minimum-bias triggers of the experiment, or by local generation of trigger pulses for the continuous mode. And the field-programmable devices of the RU allows for future updates and changes of functionality, which can be performed remotely via several redundant paths to the RUs. This is an important feature, since the RUs are not easily accessible when they are installed in the cavern of the experiment and will be exposed to radiation when the LHC is in operation. Radiation tolerance has been an important concern during the development of the FPGA designs, as well as the RU hardware itself, since radiation-induced errors in the RUs are expected during operation. Techniques such as Triple Modular Redundancy (TMR) were used in the FPGA designs to mitigate these effects. One example is the radiation tolerant CAN controller design which is introduced in this thesis. A different challenge, which is also addressed in this thesis, is the monitoring of internal status and quantities such as temperature and voltage in the ALPIDE chips. This is performed over the ALPIDE’s control bus, but must be carefully coordinated as the control bus is also used for triggers. The detector and readout electronics are designed to operate under a wide set of conditions. Considering events from Pb–Pb collisions, which may have thousands of pixel hits in the detector, a typical pp event has comparatively few pixel hits, but the collision rate is significantly higher for pp runs than it is for Pb–Pb runs. And the detector can be used with two triggering modes, where the continuous trigger mode has additional parameters for trigger period. A simulation model of the ALPIDE and ITS, presented in this thesis, was developed to simulate the readout performance and efficiency of the detector under a wide set of circumstances. The simulated results show that the detector should perform with a high efficiency at the collision rates that are planned for Run 3. Initial plans for a dedicated hardware, to handle and coordinate busy status for the detector, was deemed superfluous and the plans were canceled based on these results. Collision rates higher than those planned for Run 3 were also simulated to yield parameters for optimal performance at those rates. For the RU, which was designed to interface to three widely different stave designs, the simulations quantified the amount of data the readout electronics will have to handle depending on the detector layer and operating conditions. Furthermore, the simulation model was adapted for simulations of two other ALPIDE-based detector projects; the Proton CT (pCT) project at University of Bergen (UiB), a Digital Tracking Calorimeter (DTC) used for dose planning of particle therapy in cancer treatment; and the planned Forward Calorimeter (FoCal) for ALICE, where there will be two layers of pixel sensors among the 18 layers of Si-W calorimeter pads in the electromagnetic part of the detector (FoCal-E). Since the size of a calorimeter pad is relatively large, around 1 cm², the fine grained pixels of the ALPIDE (29.24 µm × 26.88 µm) will help distinguish between multiple showers and improve the overall spatial resolution of the detector. The simulations helped prove the feasibility of the ALPIDE for this detector, from a readout perspective, and FoCal was later approved by the LHCC committee at CERN.Doktorgradsavhandlin

    Plant Biodiversity and Genetic Resources

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    The papers included in this Special Issue address a variety of important aspects of plant biodiversity and genetic resources, including definitions, descriptions, and illustrations of different components and their value for food and nutrition security, breeding, and environmental services. Furthermore, comprehensive information is provided regarding conservation approaches and techniques for plant genetic resources, policy aspects, and results of biological, genetic, morphological, economic, social, and breeding-related research activities. The complexity and vulnerability of (plant) biodiversity and its inherent genetic resources, as an integral part of the contextual ecosystem and the human web of life, are clearly demonstrated in this Special Issue, and for several encountered problems and constraints, possible approaches or solutions are presented to overcome these

    Advanced Applications of Rapid Prototyping Technology in Modern Engineering

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    Rapid prototyping (RP) technology has been widely known and appreciated due to its flexible and customized manufacturing capabilities. The widely studied RP techniques include stereolithography apparatus (SLA), selective laser sintering (SLS), three-dimensional printing (3DP), fused deposition modeling (FDM), 3D plotting, solid ground curing (SGC), multiphase jet solidification (MJS), laminated object manufacturing (LOM). Different techniques are associated with different materials and/or processing principles and thus are devoted to specific applications. RP technology has no longer been only for prototype building rather has been extended for real industrial manufacturing solutions. Today, the RP technology has contributed to almost all engineering areas that include mechanical, materials, industrial, aerospace, electrical and most recently biomedical engineering. This book aims to present the advanced development of RP technologies in various engineering areas as the solutions to the real world engineering problems
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