Microbunching instability characterization via temporally modulated laser pulses

High-brightness electron bunches, such as those generated and accelerated in free-electron lasers (FELs), can develop small-scale structure in the longitudinal phase space. This causes variations in the slice energy spread and current profile of the bunch which then undergo amplification, in an effect known as the microbunching instability. By imposing energy spread modulations on the bunch in the low-energy section of an accelerator, using an undulator and a modulated laser pulse in the centre of a dispersive chicane, it is possible tomanipulate the bunch longitudinal phase space. This allows for the control and study of the instability in unprecedented detail. We report measurements and analysis of such modulated electron bunches in the 2Dspectro-temporal domain at the FERMI FEL, for three different bunch compression schemes. We also perform corresponding simulations of these experiments and show that the codes are indeed able to reproduce the measurements across a wide spectral range. This detailed experimental verification of the ability of codes to capture the essential beam dynamics of the microbunching instability will benefit the design and performance of future FELs

Microbunching instability characterization via temporally modulated laser pulses

High-brightness electron bunches, such as those generated and accelerated in free-electron lasers (FELs), can develop small-scale structure in the longitudinal phase space. This causes variations in the slice energy spread and current profile of the bunch which then undergo amplification, in an effect known as the microbunching instability. By imposing energy spread modulations on the bunch in the low-energy section of an accelerator, using an undulator and a modulated laser pulse in the center of a dispersive chicane, it is possible to manipulate the bunch longitudinal phase space. This allows for the control and study of the instability in unprecedented detail. We report measurements and analysis of such modulated electron bunches in the 2D spectrotemporal domain at the Fermi FEL, for three different bunch compression schemes. We also perform corresponding simulations of these experiments and show that the codes are indeed able to reproduce the measurements across a wide spectral range. This detailed experimental verification of the ability of codes to capture the essential beam dynamics of the microbunching instability will benefit the design and performance of future FELs

A autoavaliação institucional no processo de tomada de decisão em IES: estudo de caso das Faculdades SENAC/SC Institutional self-evaluation in the decision-making process at HEIs: a case study of SENAC/SC higher education school

O presente artigo pretende demonstrar em seu contexto a relação existente entre o sistema de autoavaliação institucional e o processo de tomada de decisão, especificamente nas Faculdades de Tecnologia pertencentes à Administração Regional do SENAC-SC. Utilizando uma amostra intencional deste universo, o estudo, realizado em 2010, é caracterizado como descritivo-exploratório, do tipo quali-quantitativo, mediante a aplicação de uma pesquisa bibliográfico-documental, configurada como um estudo multicaso. Nas seis unidades investigadas, foram entrevistados: o diretor da unidade e os coordenadores de áreas (Núcleo Relações com o Mercado, Núcleo Administrativo Financeiro e Núcleos Educacional Básico e do Ensino Superior), aplicando-se um questionário estruturado com questões abertas e fechadas, permitindo a avaliação de aspectos objetivos e quantificáveis e subjetivo-discursivos. Os resultados apontam para a autoavaliação institucional como facilitadora do processo decisório, provendo informações que permitem avaliar determinada situação. Adicionalmente, identificam os pontos fortes e fracos da IES e que melhoram a qualidade das decisões estratégicas, o que confirma a existência da relação pressuposta acima, bem como a importância do processo de autoavaliação institucional. Mostram, ainda, a necessidade de revisão da estrutura, visando aprimorar a apropriação dos dados levantados pela autoavaliação e aplicados como suporte no processo de tomada de decisão das instituições do universo analisado. Por fim, a hipótese de pesquisa, em base a esses resultados, acabou sendo validada, ratificando tal relação.<br>This article presents, briefly, the master thesis that gave rise and that analyzes the institutional self-evaluation and the decision-making process at SENAC-SC and the relationship between them. By using an intentional sample of six technology universities belonging to the regional administration of SENAC-SC, this research, carried out in June and July 2010 (cross-sectional basis, i.e., during the current year), had the main purpose of analyzing the institutional self-evaluation and its influence over the decision-making process, supplemented by its specific purposes that were: describe these two processes; identify the appropriation of the results from the institutional self-evaluation in the SENAC-SC universities; and list and discuss those elements that either make it easier or difficult to appropriate such results in the decision-making process within the institution. The study was characterized as a qualitative/quantitative-type descriptive-exploratory study upon the application of a bibliographic-documentary research configured as a multi-case study. Interviews were carried out at each investigated university with: The director of the unit and the area coordinators (market relationship core, administrative/financial core and basic and superior education core), who are understood as the managers of these institutions. A structured questionnaire was applied, containing open and closed-type questions, in the mentioned period, in order to evaluate not only objective and aspects, but also subjective-discursive aspects. The main results have confirmed the existence of the above-assumed relationship, including the importance of the institutional self-evaluation process. In addition and in attention to the specific goals, they indicate that notwithstanding such importance, its structure needs to be revised in order to improve such relationship and improve the appropriation of the surveyed data by the self-evaluation and apply them as an auxiliary means for the decision-making process of the universities in the analyzed universe. The research hypothesis, which was predicting that the institutional self-evaluation, when established in an institution, influences with the provision of subsidies, the decision-making process, was validated by the results