Superconducting elliptical cavities

We give a brief overview of the history, state of the art, and future for elliptical superconducting cavities. Principles of the cell shape optimization, criteria for multi-cell structures design, HOM damping schemes and other features are discussed along with examples of superconducting structures for various applications.Comment: 25 pages, contribution to the CAS - CERN Accelerator School: Specialised Course on RF for Accelerators; 8 - 17 Jun 2010, Ebeltoft, Denmar

Superconducting Superstructure for the TESLA Collider

We discuss the new layout of a cavity chain (superstructure) allowing, we hope, significant cost reduction of the RF system of both linacs of the TESLA linear collider. The proposed scheme increases the fill factor and thus makes an effective gradient of an accelerator higher. We present mainly computations we have performed up to now and which encouraged us to order the copper model of the scheme, still keeping in mind that experiments with a beam will be necessary to prove if the proposed solution can be used for the acceleration.Comment: 11 page

Prospects for CW and LP operation of the European XFEL in hard X-ray regime

The European XFEL will operate nominally at 17.5 GeV in SP (short pulse) mode with 0.65 ms long bunch train and 10 Hz repetition rate. A possible upgrade of the linac to CW (continuous wave) or LP (long pulse) modes with a corresponding reduction of electron beam energy is under discussion since many years. Recent successes in the dedicated R&D program allow to forecast a technical feasibility of such an upgrade in the foreseeable future. One of the challenges is to provide sub-Angstrom FEL operation in CW and LP modes. In this paper we perform a preliminary analysis of a possible operation of the European XFEL in the hard X-ray regime in CW and LP modes with the energies of 7 GeV and 10 GeV, respectively. We consider lasing in the baseline XFEL undulator as well as in a new undulator with a reduced period. We show that, with reasonable requirements on electron beam quality, lasing on the fundamental will be possible in sub-Angstrom regime. As an option for generation of brilliant photon beams at short wavelengths we also consider harmonic lasing that has recently attracted a significant attention

Kobieta-matka w roli menedżera – na przykładzie wybranych przedsiębiorstw

Celem pracy było zbadanie jak w roli menedżera sprawdza się kobieta - matka. Ocenie poddano kompetencje, bariery z jakimi stykają się na swej ścieżce kariery i szanse na awans. Autorka w części teoretycznej pracy, w oparciu o dostępną literaturę przedmiotu dokonała analizy problemów związanych z istotą zawodu menedżera. W szczególności podstawowych pojęć, cech, ról i kompetencji menedżera, różnic w stylach zarządzania wynikających z odmienności płci i barier oraz wyzwań przed jakimi stoją kobiety w roli menedżera. Ponadto w rozdziale teoretycznym autorka zaprezentowała modelowe charakterystyki kobiet pełniących funkcje menedżerskie na najwyższych szczeblach zarządczych. W części empirycznej swojej pracy dokonała weryfikacji teorii zawartej w części pierwszej i drugiej pracy (teoretycznej). Poddała analizie główny problem badawczy, który stanowił identyfikację czynników mających największy wpływ na trudności w uzyskaniu awansu przez kobiety na stanowiska menedżerskie. A także zweryfikowała dwie hipotezy świadczące o wysokich kompetencjach menedżerskich kobiet i skuteczności ich stylu zarządzania we współczesnych przedsiębiorstwach. W celu sprawdzenia powyższych założeń badaniu ankietowemu poddano 25 kobiet-menedżerów. W wyniku przeprowadzonych badań udało się potwierdzić założone hipotezy. Było to możliwe dzięki kompleksowej analizie, której poddano szeroki wachlarz czynników mających wpływ na szanse kobiet w sektorze zdominowanym przez mężczyzn.The aim of this master thesis was to study how a woman - mother works as a manager. Competences, barriers faced in their career paths and chances for promotion were assessed. The author, in the theoretical part of the master thesis, based on the available literature, analyzed the problems related to the essence of the managerial profession. In particular, the basic concepts, features, roles and competences of a manager, differences in management styles resulting from gender differences and barriers, and the challenges women face as managers. In addition, in the theoretical chapter the author presented model characteristics of women performing managerial functions at the top management levels. In the empirical part of her work, she verified the theory contained in the first and second (theoretical) chapters. She analyzed the main research problem, which was the identification of the factors that have the greatest impact on the difficulty in promoting women to managerial positions. She also verified two hypothesis demonstrating the high managerial competences of women and the effectiveness of their management styles in modern enterprises. In order to check the above assumptions, 25 female managers were surveyed. As a result of the research, the hypothesis were confirmed. This was possible thanks to a comprehensive analysis of a wide range of factors affecting women's growth chances in a male-dominated sector

Optimization and beam dynamics of a superconducting radio-frequency gun

Recent advances in superconducting radio-frequency (RF) technology and a better understanding of RF photoinjector design optimization make it possible to propose a specific design for a superconducting RF gun that can simultaneously produce both ultra-high peak brightness and high average current. Such a device is a critical component of next generation X-ray sources, such as self-amplified spontaneous emission free-electron lasers (SASE FEL) and energy recovery linac-based systems. The design presented in this paper is scaled from the present state-of-the-art normal conducting RF photoinjector that has been studied in the context of the linac coherent light source and SPARC SASE FEL injection schemes. Issues specific to the superconducing RF photoinjector, such as accelerating gradient limit, RF cavity and cryostat design, and compatibility with magnetic focusing and laser excitation of a photocathode are discussed

A multimodal neuroimaging classifier for alcohol dependence

With progress in magnetic resonance imaging technology and a broader dissemination of state-of-the-art imaging facilities, the acquisition of multiple neuroimaging modalities is becoming increasingly feasible. One particular hope associated with multimodal neuroimaging is the development of reliable data-driven diagnostic classifiers for psychiatric disorders, yet previous studies have often failed to find a benefit of combining multiple modalities. As a psychiatric disorder with established neurobiological effects at several levels of description, alcohol dependence is particularly well-suited for multimodal classification. To this aim, we developed a multimodal classification scheme and applied it to a rich neuroimaging battery (structural, functional task-based and functional resting-state data) collected in a matched sample of alcohol-dependent patients (N = 119) and controls (N = 97). We found that our classification scheme yielded 79.3% diagnostic accuracy, which outperformed the strongest individual modality - grey-matter density - by 2.7%. We found that this moderate benefit of multimodal classification depended on a number of critical design choices: a procedure to select optimal modality-specific classifiers, a fine-grained ensemble prediction based on cross-modal weight matrices and continuous classifier decision values. We conclude that the combination of multiple neuroimaging modalities is able to moderately improve the accuracy of machine-learning-based diagnostic classification in alcohol dependence