The European XFEL is an X-ray free electron laser research facility that generates ultrashort, high intensity flashes. Three SASE undulator systems are made of undulator segments and intersection components. Permanent magnets that form the segments, may potentially suffer demagnetization due to the stray radiation that comes from the interaction between electrons and the beam pipe. A gamma spectrometer (GR1-A, developed by Kromek) is planned to be placed at the entrance of one of the undulator segments of SASE1. Monte Carlo simulations, using Geant4, have been performed to study gamma radiation flux at possible measurement areas. The results show that in some cells the expected flux is larger than the maximum throughput, while for two segments there are areas which satisfy the limitations of the detector. An improvement of the geometry of the Geant4 code has also been done to make simulations more in line with the real systems. A comparison between dose results from the new and the former code shows that components placed at the intersections have a significant impact on dose distributions, especially quadrupole magnets.

No description available.

La source européenne de spallation (ESS) sera une infrastructure de recherche dévolue aux sciences utilisant les neutrons comme sonde d’observation. Elle est actuellement en construction à Lund, en Suède, et sera la plus brillante des sources de neutrons pulsées au monde. Comme son nom l'indique, la production des neutrons est assurée par les processus de spallation : des protons à haute énergie bombardant une cible de tungstène. Le faisceau de protons est généré par un puissant accélérateur linéaire de 2 GeV qui peut être divisé en deux parties : une partie "chaude" qui accélère les protons jusqu'à 90 MeV, suivie d’une partie « froide » constituée de cavités supraconductrices refroidies à l'hélium liquide, permettant d’atteindre les 2 GeV. La forte intensité de 62.5 mA et la longue impulsion de 2,86 ms répétée 14 fois par seconde, conduisent à une puissance moyenne de faisceau de 5 MW et une puissance crête de 125 MW. La connaissance du faisceau est donc indispensable pour la mise en service, c'est-à-dire le réglage du faisceau afin d'assurer un fonctionnement correct et sûr de la machine. Différents diagnostics seront installés le long de l'accélérateur pour remplir ces tâches.Cette thèse traite du développement d'un profileur transverse non invasif pour la partie froide de l’accélérateur de ESS : les Ionization Profile Monitors (IPM). La thèse se concentre sur les aspects critiques des IPM afin de s’assurer de leur faisabilité dans les conditions du faisceau de ESS. Ces moniteurs sont basés sur l’ionisation induite par le passage des protons du gaz résiduel présent dans le tube de l’accélérateur. Un champ électrique est appliqué entre deux plaques parallèles de l'IPM. Les électrons ou les ions dérivent vers un détecteur segmenté permettant de reconstruire le profil dans une direction transverse du faisceau.Plusieurs défis, qui auraient pu compromettre l’utilisation des IPM pour les mesures des profils de faisceau à ESS, sont décrits :• Les faibles taux de comptage dus aux faibles sections efficaces d'ionisation à haute énergie (90 à 2000 MeV) ainsi qu’aux basses pressions du gaz résiduel de l’ordre de 10-9 mbar,• L'homogénéité du champ électrique à l'intérieur de l'IPM, essentiel pour assurer des mesures de profils précises mais difficile pour les chambres à vide étriquées des IPM,• L’importante charge d'espace du faisceau, qui distord le profil mesuré en déviant lestrajectoires des produits d'ionisation. Cet aspect fondamental peut remettre en cause l’utilisation d’IPM pour faire des mesures fiables de profil de faisceau.Une fois ces études terminées, nous avons sélectionné trois systèmes de lecture fiables, basés sur :• des pistes conductrices lues par un intégrateur de charge multicanal,• des détecteurs à micro-canaux couplés à un écran phosphore (pMCP),• un détecteur de silicium développé au CERN, et utilisé en particulier pour le futur profileur du faisceau du PS.Ces études ont fait l’objet d’une Revue de Conception Préliminaire (PDR 2017/01) marquant le début de la construction des différents prototypes. Les tests préliminaires ont écarté la possibilité d'utiliser des détecteurs au silicium en raison des trop faibles énergies des ions incidents.En partant de zéro, des IPM, des moniteurs de référence et un banc d’essai ont été conçus et installés sur l’accélérateur de protons IPHI à Saclay. Les conditions expérimentales de ESS ont été reproduites afin de valider une solution pour les IPM, ainsi que tester nos modèles.Les campagnes de test ont montré qu'un MCP était nécessaire pour détecter le signal d’ionisation. De plus, l'IPM optique (pMCP + caméra) est la solution recommandée car elle offre une sensibilité plus élevée. Le retour d’expérience accumulé lors des tests des prototypes, nous a permis de proposer une conception quasi finale d’un IPM, présentée lors de la Revue Critique de Conception (CDR 2019/02), menant au début de la phase de production. / The European Spallation Source (ESS) will be a research infrastructure dedicated to sciences using neutrons as probes. The source is currently under construction in Lund, Sweden, and will be the world’s brightest pulsed source of neutrons. As its name suggests, the production of neutrons is ensured by the spallation process: high energy protons will impinge a tungsten target. To accelerate the protons, a powerful 2 GeV linear accelerator is being built. The accelerator can be split in two parts. A “hot” part is responsible for acceleration up to 90 MeV. Then a “cold” part made of superconducting cavities cooled with liquid helium is used to reach the highest energies. The high intensity of 62.5 mA and he long pulse of 2.86 ms repeated 14 times per second, lead to an incredible beam power of 5 MW in average and 125 MW in peak. The knowledge of the beam is therefore mandatory to ensure the commissioning, i.e. the beam tuning in order to achieve a proper and safe functioning of the machine. Different diagnostics will be installed along the accelerator to fulfil these tasks.This thesis deals with the development of a non-invasive transverse profiler for the cold part of the ESS accelerator: the Ionization Profile Monitor (IPM).The thesis focuses on critical aspects of the IPMs to guarantee its feasibility in ESS beam conditions. These monitors are based on the ionization of the residual gas induced by the proton beam inside the beam pipe. A transverse electrical field is generated between both parallel plates of the IPM. The electrons or ions drift, with respect to the electric field, towards a segmented detector allowing the reconstruction of the beam profile in one transverse direction. For a complete transverse profile, it is necessary to add a second profiler tilted by 90°.Several challenges for facing IPM to the ESS conditions, which may compromise their use, are described:• the weak counting rates due to the low ionization cross-sections at high energy (90 to 2000 MeV) and to the low residual gas pressure of 10-9 mbar,• the electric field homogeneity inside the IPM, which is relevant for insuring a precise profile measurement, was not obvious in the narrow vacuum chambers devoted to them,• the large Space Charge Effect of the beam, distorting the measured profile by deviating the ionization by-product trajectories. This fundamental aspect may compromise the use of an IPM for beam profile measurements.Once these former studies done, we selected the three reliable read-out systems based on:• conductive strips read by a multichannel charge integrator,• micro-channel plates coupled with phosphor screen (pMCP),• a silicon detector developed at CERN and foreseen for the future PS beam profiler.This work was the object of the Preliminary Design Review (PDR 2017/01) marking the beginning of the construction phase of the different prototypes. Preliminary tests discarded the possibility of using silicon detectors due to the low ion energies.Starting from scratch, IPMs, reference monitors and a test bench were designed and installed at the IPHI proton accelerator at Saclay. Close ESS conditions were achieved to validate an IPM solution and our simulations.The test campaigns showed that an MCP is mandatory to detect signal. Moreover, the optical IPM (pMCP + Camera) is the preferred solution since it provides higher sensitivity. Feedbacks from the prototype test campaigns, allows us to deliver an IPM final design presented during the Critical Design Review (CDR 2019/02) leading to the beginning of the production phase.

Future magnetic fusion reactors such as tokamaks will need innovative, fast, deep-fueling systems to inject frozen deuterium-tritium pellets at high speeds and high repetition rates into the hot plasma core. There have been several studies and concepts for pellet injectors generated, and different devices have been proposed. In addition to fueling, recent studies show that it may be possible to disrupt edge localized mode (ELM) formation by injecting pellets or gas into the fusion plasma. The system studied is capable of doing either at a variety of plasma and pellet velocities, volumes, and repetition rates that can be controlled through the formation conditions of the plasma. In magnetic or inertial fusion reactors, hydrogen, its isotopes, and lithium are used as fusion fueling materials. Lithium is considered a fusion fuel and not an impurity in fusion reactors as it can be used to produce fusion energy and breed fusion products. Lithium hydride and lithium deuteride may serve as good ablating sleeves for plasma formation in an ablation-dominated electrothermal plasma source to propel fusion pellets. Previous studies have shown that pellet exit velocities, greater 3 km/s, are possible using low-z propellant materials. In this work, a comprehensive study of solid lithium hydride and deuteride as a pellet propellant is conducted using the ETFLOW code, and relationships between propellants, source and barrel geometry, pellet volume and aspect ratio, and pellet velocity are determined for pellets ranging in volume from 1 to 100 mm3. / Master of Science

Background: The Corporate Accelerator (CA) trend has extended beyond high technology industries, gaining global traction across a variety of industries, such as in finance, healthcare, insurance, entertainment and consumer packaged goods. CAs are described as an approach that bridges the gap between corporations and startups, further supporting long-term growth and corporate renewal. When organized effectively, CAs provide a platform that allows both the established corporations and startups to tap into the resources of what one has and the other lacks. Despite its’ many opportunities, some aspects of CAs have also been criticized. In particular, CAs aim to fulfill their corporation’s goals which may lead to discrepancies between the goals of the corporation and the startup. This could potentially limit the level of innovativeness of the startups as well as other learning benefits they aimed to achieve from taking part in the program. Purpose: From an entrepreneur’s point of view, this study aims to understand the learning experiences CA programs offer for participating startups. Method: An instrumental collective case study was conducted in the form of semi-structured interviews from five cases that represented five different CA programs. Conclusion: This study aims to elaborate the existing CA literature through providing insights about how individuals in startups develop new knowledge through taking part in CA programs. The findings of this study suggest that three main factors affect the startup individuals learning experiences in CA programs that consist of; (1) The need for learning that is built upon the background attributes of each startup individual and the stage at which the startup organization is at; (2) The different entrepreneurial support activities that offer the startups authentic learning, generative learning and acquisitive learning opportunities; (3) The learning network offered during the program that consists of corporations, facilitator organizations and other startup organizations that enable the startup individuals to acquire complementary knowledge resources across their own organizational boundaries. Moreover, the findings of this study illustrate that experiences gained during the program are transformed into entrepreneurial knowledge that constitutes to the individual's ability to recognize new opportunities as well as the ability to cope with the liabilities of newness.

This work deals with topic of LAMP software bundle performance optimalization. Step by step, it tries to discover performance problems in all four parts of LAMP (in Linux, HTTP server Apache, MySQL database and PHP language interpreter). A model web application is created for these testing purposes. When a problem is found, a change in configuration files is done or a performance improving technology is applied to the corresponding part. A set of optimalization recommendations is compiled and verified on server running real web application.

No description available.

No description available.

[pt] O propósito da pesquisa descrita foi investigar o recente fenômeno da criação de aceleradoras de startups digitais por empresas brasileiras de grande porte, uma tendência no mercado brasileiro e global. Apesar de existir bastante literatura acerca do tema de inovação corporativa, poucos autores estudaram o envolvimento entre corporações e startups através da implementação de aceleradoras corporativas, já que este é um modelo bastante recente, tanto no Brasil quanto no exterior. Por isso, este estudo busca entender que motivações estão por trás do investimento neste modelo, quais os benefícios percebidos por empresas que já o desenvolveram e quais os ajustes necessários no modelo de aceleração corporativa. Para tal, os únicos dois casos existentes de aceleradoras de startups lançadas por corporações brasileiras de grande porte foram analisados. Foram conduzidas entrevistas em profundidade com os gestores responsáveis pelas atividades de inovação e pela criação das aceleradoras corporativas dentro de cada organização, de forma a identificar diretamente da fonte os principais problemas existentes na realização de atividades de inovação anteriores e as motivações que levaram as empresas à escolha deste novo modelo de envolvimento com iniciativas digitais nascentes. O estudo identificou que as corporações possuem dificuldade em inovar devido à falta de alinhamento de expectativas internas, principalmente de retorno financeiro, e ao engessamento da estrutura corporativa, que reduz a velocidade de atividades ligadas à inovação. Existem, por outro lado, fortes motivações para alterar o modelo de atuação e a forma de se pensar a inovação por meio da implementação de aceleradoras corporativas, como a necessidade de acompanhar melhor as tendências do mercado, a crescente importância da presença no ambiente digital para melhorar as relações com os clientes, a influência do envolvimento anterior da liderança das organizações com empreendedorismo e a existência de modelos já comprovados fora do Brasil. Apesar de as aceleradoras corporativas ainda estarem em estágio inicial e não apresentarem resultados significativos, é possível identificar claramente os benefícios esperados pelas organizações. Alguns já estão mais presentes, como a melhora da imagem institucional das organizações devido ao investimento em inovação. Por outro lado, os principais benefícios esperados, como a transformação cultural da empresa e o retorno financeiro dos investimentos realizados, ainda não são uma realidade. Percebe-se, dessa forma, que as aceleradoras corporativas ainda não contaminam de forma suficientemente forte as organizações, principalmente por não possuírem o nível de exposição adequado aos profissionais que não estão diretamente envolvidos na sua operação. As aceleradoras corporativas surgem como uma nova opção de envolvimento com startups, de forma a unir a velocidade de execução e a flexibilidade de empresas tecnológicas de pequeno porte com a capacidade de escala, a experiência e o financiamento de grandes corporações. Estas estruturas possibilitam que elas desenvolvam uma operação de inovação independente da sua influência, libertando o desenvolvimento de novas ideias e projetos do engessamento dos processos e regras corporativos. Dessa forma, é possível agregar valor à organização tanto com o desenvolvimento de novos negócios quanto com a geração de complementadores para produtos e serviços já existentes, melhorando o posicionamento estratégico da empresa no ambiente competitivo. / [en] The purpose of this study is to investigate the recent phenomenon of creation of digital accelerators by large Brazilian corporations, a trend in the Brazilian and global market. Although there is much literature available on the subject of corporate innovation, few authors have studied the involvement of corporations and startups through the implementation of corporate accelerators, since this is a fairly recent model, both in Brazil and abroad. Therefore, this study seeks to understand what motivations are behind the investment in this model, which benefits are expected by companies that have developed it and what adjustments are needed in the corporate acceleration model. To this end, the only two existing cases of accelerator of startups launched by large Brazilian corporations were analyzed. Depth interviews were conducted with the managers responsible for innovation activities and for the creation of the corporate accelerator within each organization, in order to identify directly from the source the main problems in the implementation of past innovation activities and the motivations that led the companies to choose this new model of engagement with new digital ventures. The study identified that corporations have difficulty to innovate due to lack of alignment of internal expectations, especially of financial return, and the inflexibility of the corporate structure, which reduces the speed of activities related to innovation. There are, moreover, strong motivations to change the operating model and the way of thinking innovation through the implementation of corporate accelerators such as the need to better monitor the market trends, the growing importance of presence in the digital environment in order to improve relations with customers, the influence of previous involvement with entrepreneurship by the leadership of organizations, and the existence of proven models outside Brazil. Although corporate accelerators are still at an early stage and do not present significant results, it is possible to clearly identify the benefits expected by the organizations. Some already exist, such as the improvement of the institutional image of the organizations due to investment in innovation. On the other hand, the main benefits expected, as the cultural transformation of the company and the financial return on investment, are still not a reality. It is clear, therefore, that corporate accelerator has not contaminate strongly enough these organizations, mainly because they lack the appropriate exposure level for professionals who are not directly involved in its operation. Corporate accelerators emerge as a new option of involvement with startups, putting together the speed of execution and flexibility of small technology companies with the ability to scale, experience and deep pockets of large corporations. These structures enable them to develop an independent innovation operation that is not impacted by its influence, freeing the development of new ideas and projects from immobilization processes and business rules. Thus, it is possible to add value to the organization both with the development of new business and the generation of complementers to existing products and services, improving the strategic positioning of the company in the competitive environment.

The Super Proton Synchrotron (SPS) injection system plays a fundamental role to preserve the quality of injected high-brightness beams for the LHC physics program and to maintain the maximum storable intensity. The present set-up is the result of years of upgrades and patches of a system that was not conceived for such intensities and beam qualities. In this study, we propose the design of a completely new injection system based on multi-level numerical optimisation of the different constraints, including realistic hardware assumptions. We present the different algorithms and procedures applied in the optimisation process, and we also outline how this generic optimisation framework can be adapted to other situations for optimal accelerator system design.