The advantages of contemporary particle injectors are high bunch charges and good beam quality in the case of normal conducting RF guns and increased repetition rates in the one of DC injectors. The technological edge of the concept of superconducting radio frequency injectors is to combine the strengths of both these sides. As many future accelerator concepts, such as energy recovery linacs, high power free electron lasers and certain collider designs, demand particle sources with high bunch charges and high repetition rates combined, applying the superconductivity of the accelerator modules to the injector itself is the next logical step. However, emittance compensation — the cornerstone for high beam quality — in case of a superconducting injector is much more challenging than in the normal conducting one. The use of simple electromagnets generating a solenoid field around the gun’s resonator interferes with its superconducting state. Hence, it requires novel and sophisticated techniques to maintain the high energy gain inside the gun cavity, while at the same time alleviating the detrimental fast transverse emittance growth of the bunch. In the case of the ELBE accelerator at the Helmholtz-Zentrum Dresden-Rossendorf, a superconducting electron accelerator provides beam for several independent beamlines in continuous wave mode. The applications include IR to THz free electron lasers, neutron and positron generation, to Thompson backscattering with an inhouse TW laser, and hence, call for a flexible CW injector. Therefore, the development of a 3.5 cell superconducting electron gun was initiated in 1997. The focus of this thesis lies on three approaches of transverse emittance compensation for this photoinjector: RF focusing, the installation of a superconducting solenoid close to the cavity’s exit, and the introduction of a transverse electrical mode of the RF field in the resonator. All three methods are described in theory, examined by numerical simulation, and experimentally reviewed in the particular case of the ELBE SRF Gun II at HZDR and a copy of its niobium resonator at Thomas Jefferson National Laboratory, Newport News, VA, USA.

The advantages of contemporary particle injectors are high bunch charges and good beam quality in the case of normal conducting RF guns and increased repetition rates in the one of DC injectors. The technological edge of the concept of superconducting radio frequency injectors is to combine the strengths of both these sides. As many future accelerator concepts, such as energy recovery linacs, high power free electron lasers and certain collider designs, demand particle sources with high bunch charges and high repetition rates combined, applying the superconductivity of the accelerator modules to the injector itself is the next logical step. However, emittance compensation — the cornerstone for high beam quality — in case of a superconducting injector is much more challenging than in the normal conducting one. The use of simple electromagnets generating a solenoid field around the gun’s resonator interferes with its superconducting state. Hence, it requires novel and sophisticated techniques to maintain the high energy gain inside the gun cavity, while at the same time alleviating the detrimental fast transverse emittance growth of the bunch. In the case of the ELBE accelerator at the Helmholtz-Zentrum Dresden-Rossendorf, a superconducting electron accelerator provides beam for several independent beamlines in continuous wave mode. The applications include IR to THz free electron lasers, neutron and positron generation, to Thompson backscattering with an inhouse TW laser, and hence, call for a flexible CW injector. Therefore, the development of a 3.5 cell superconducting electron gun was initiated in 1997. The focus of this thesis lies on three approaches of transverse emittance compensation for this photoinjector: RF focusing, the installation of a superconducting solenoid close to the cavity’s exit, and the introduction of a transverse electrical mode of the RF field in the resonator. All three methods are described in theory, examined by numerical simulation, and experimentally reviewed in the particular case of the ELBE SRF Gun II at HZDR and a copy of its niobium resonator at Thomas Jefferson National Laboratory, Newport News, VA, USA.

The TRIUMF view screen system encompases a set of devices which individually image, and produce measurements of, the transverse profile of an accelerated electron beam. A control system is an essential component of the overall diagnostic device. The system requirements were compiled from those produced by the TRIUMF laboratory and from those based on the needs of the individual diagnostic devices. Based on the requirements, a control system was designed and implemented with a combination of industrial electrical and mechanical hardware, and a variety of software components. One component of the image reconstruction algorithm was validated with experimental data; the accuracy and precision of beam profile measurements was evaluated through simulation studies. Although it was not possible to demonstrate the satisfaction of requirements relating to alignment, it was shown that all other requirements were satisfied. / Graduate / 0798 / 0752 / 0605

In recent years, accelerators have gained increasingly attention due to their numerical growth, geographic dispersion, and growing numbers of participants they have worked with. Uber, Airbnb, Dropbox or Reddit – they have not only been participants of accelerators, but they can also be identified as ‘Born Globals’ according to the definition used throughout this thesis. Considering this fact and the lack of research in theory on the interrelation of both phenomena, accelerators and Born Global, it is interesting to dig deeper into the impact accelerators have on their respective participants’ global development. For this purpose, the authors conducted a multiple-case study to find answers to the question of what elements of accelerators promote participants to become Born Globals. This multiple-case study included semi-structured interviews with managers of four different cases of accelerators and three respective former participants as well as complementarily used secondary data in terms of company documents. Drawing from empirical evidence, it was found that the major elements of the examined accelerators fostering the participants’ development towards Born Globals can be summarized into five major categories: ’Application Process’, ’Interpersonal Connections’, ’Product & Coaching Methodologies’, ’Education’, and ‘Startup Community & Entrepreneurial Ecosystem’.

Wakefields and the corresponding frequency-domain phenomenon beam coupling impedance have been well studied for a number of years as a source of beam instabilities within particle accelerators. With the development of the Large Hadron Collider (LHC) and the large beam currents stored in the LHC during fills for physics production, wakefield driven instabilities and strong beam induced heating have become a limiting factors in luminosity production due to both instantaneous luminousity and the available time for collisions.In this thesis is presented an in depth study of the beam coupling impedance of two important (from an impedance and operational point of view) devices in the LHC; the collimation system and the injection kicker magnets (MKIs). These systems have both been sources of concern for the beam impedance of the LHC, the collimators due to their large transverse impedance and the MKIs due to the strong heating observed during the increased of beam current during operation in 2011 and 2012. The source of the heating for the MKIs is studied in depth, found to be power lost by the beam to wakefields in the MKIs. Simulations and measurements are used to characterise the impedance and localise the areas responsible for the high impedance, here the beam screen and ferrite yoke of the magnet; improvements are proposed to better screen the ferrite yoke and verified. A new RF damping system using ferrite for the collimation system is studied and compared to the existing RF damping system, focusing on the heating of the damping system. Highlights include a new method for measuring the quadrupolar and constant transverse impedances of an asymmetric structure using a coaxial wire technique is proposed and verified using computational simulations, and a study of the heat loss in a ferrite damped cavity, focusing on the location of the power loss for cavities being damped to varying degrees.

The development of an accurate and precise geochronology is imperative to understanding archives containing information about Earth’s past. Unable to date all intervals of an archive, researchers use methods of interpolation to approximate age between dates. Sections of the radiocarbon calibration curve can induce larger chronological uncertainty independent of instrumental precision, meaning even a precise date may carry inflated error in its calibration to a calendar age. Methods of interpolation range from step-wise linear regression to, most recently, Bayesian statistical models. These employ prior knowledge of accumulation rate to provide a more informed interpolation between neighboring dates. This study uses a Bayesian statistical accumulation model to inform non-sequential dating of a sediment core using a high-throughput gas-accepting accelerator mass spectrometer. Chronological uncertainty was iteratively improved but approached an asymptote due to a blend of calibration uncertainty, instrument error and sampling frequency. This novel method resulted in a superior chronology when compared to a traditional sediment core chronology with fewer, but more precise, dates from the same location. The high-resolution chronology was constructed for a gravity core from the Pigmy Basin with an overall 95% confidence age range of 360 years, unmatched by the previously established chronology of 460 years. This research reveals that a larger number of low-precision dates requires less interpolation, resulting in a more robust chronology than one based on fewer high-precision measurements necessitating a higher degree of age interpolation.

Iodine-129 is a naturally and anthropogenically produced radioisotope (half-life: 15.7 million years) the majority of which is produced by nuclear fuel reprocessing. These releases have dispersed 129I throughout the environment making it possible to use 129I as a tracer. It is also of concern for the disposal of radioactive waste. This research develops a new laboratory method for 129I extraction and analysis, and explores the geochemical cycling and environmental fate of 129I in remote catchments following the Fukushima-Daiichi Nuclear Accident (FDNA). A new technique was developed to investigate 129I partitioning and quantitatively extract it from solid samples. Samples are combusted and volatilized iodine is trapped in solution. The efficiency is traced using the iodine isotope, 125I. This technique was proven using standard reference materials and is used in other chapters of this thesis. A baseline study of 129I in Yukon watersheds was undertaken to determine the impact of anthropogenic 129I emissions and identify possible sources. Using atmospheric back-trajectory modeling, sources of 129I from Fukushima, nuclear fuel reprocessing and marine volatilization were identified in remote watersheds. Peat moss samples showed significant retention of 129I in modern samples. Following the reconnaissance study, a catchment scale investigation of anthropogenic 129I cycling was undertaken through precipitation and runoff monitoring. 129I was found to be an excellent indicator of initial snowmelt contributions to discharge due to enrichment by dry deposition. Furthermore, water source transitions in discharge were recorded by 129I, 127I and the 129I/127I ratio showing iodine can be used as a tracer of hydrologic processes. A mass balance found that 77% of the 129I mass input accumulates annually, primarily in organic soils. Sampling of Vancouver, B.C. precipitation and groundwater was done following the FDNA to determine the fate of 129I and evaluate it as a tracer of groundwater recharge. Immediately following the FDNA the 129I concentration in precipitation increased 6 times above background. Groundwater samples also showed 129I increases consistent with expected recharge times indicating FDNA derived 129I was transported into groundwater with minimal retardation, likely via preferential flowpaths.

In this thesis we present pvFPGA, the first system design solution for virtualizing an FPGA - based hardware accelerator on the x86 platform. The accelerator design on the FPGA can be used for accelerating various applications, regardless of the application computation latencies. Our design adopts the Xen virtual machine monitor (VMM) to build a paravirtualized environment, and a Xilinx Virtex - 6 as an FPGA accelerator. The accelerator communicates with the x86 server via PCI Express (PCIe). In comparison to the current GPU virtualization solutions, which primarily intercept and redirect API calls to the hosted or privileged domain’s user space, pvFPGA virtualizes an FPGA accelerator directly at the lower device driver layer. This gives rise to higher efficiency and lower overhead. In pvFPGA, each unprivileged domain allocates a shared data pool for both user - kernel and inter-domain data transfer. In addition, we propose the coprovisor, a new component that enables multiple domains to simultaneously access an FPGA accelerator. The experimental results have shown that 1) pvFPGA achieves close-to-zero overhead compared to accessing the FPGA accelerator without the VMM layer, 2) the FPGA accelerator is successfully shared by multiple domains, 3) distributing different maximum data transfer bandwidths to different domains can be achieved by regulating the size of the shared data pool at the split driver loading time, 4) request turnaround time is improved through DMA (Direct Memory Access) context switches implemented by the coprovisor.

Running company is very risky and its beginnings are perhaps the most difficult phase in the life cycle of a company, which in many cases discourages potential entrepreneurs from starting up. Budding entrepreneurs are yet to contend not only with the lack of start-up capital, but also with a lack of knowledge, experience and contacts that support successful business development. One way how to overcome these obstacles is to attend one of the programs of startup accelerators that provide novice entrepreneurs not only with starting capital, but also with experience, knowledge and contacts to entities that may be critical for the successful development of business. This thesis aims to determine the participants' satisfaction with Czech startup accelerator StartupYard and appraise the effectiveness of its functioning.

As part of the Large Hadron Collider high luminosity upgrade it is proposed to include crab cavities and large aperture niobium tin final focussing magnets in the lattice in order to enhance the luminosity. In this thesis the dynamics of a proposed cavity design were considered in terms of their impact upon the dynamic aperture of the machine. Taylor maps for the cavity were created and used to perform this analysis with a full assessment of their validity. A set of symplectic thin cavity models were also developed and cross checked with the Taylor maps. Finally, dynamic aperture studies were performed using these models in order to determine which components of the crab cavity dynamics are important when considering the long term stability of the beam in the LHC upgrade. It is shown that crab cavities exhibit little impact on the LHC beam stability. For the final focussing magnets a preliminary study was conducted into the importance of including their fringe fields in a model of the LHC upgrade. A technical study was carried out into developing a symplectic model which was compatible with the current magnet models use for dynamic aperture studies. A preliminary dynamic aperture study was performed with the inclusion of fringe fields for the final focussing magnets from which the fringe fields are shown to have a negative impact on the long term beam stability.