56 research outputs found

    Détermination de la matrice sigma du faisceau dans l'espace 5D

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    Note explicative sur la d√©termination de la matrice faisceau dans le cas d'une ligne coupl√©eSouvent, dans la litt√©rature, la d√©termination de la matrice sigma d'un faisceau se fait avec la supposition que les plans horizontaux et verticaux sont d√©coupl√©s. De plus, l'√©mit-tance du faisceau est d√©finie par rapport √† ces plans. Nous proposons ici une m√©thodologie pour d√©terminer la matrice du faisceau dans le cas o√Ļ le faisceau est initialement coupl√© mais √©galement dans le cas o√Ļ la ligne elle-m√™me introduit du couplage. Nous traiterons enfin le cas o√Ļ la ligne optique est √©galement dispersive

    The United States' next generation of atmospheric composition and coastal ecosystem measurements : NASA's Geostationary Coastal and Air Pollution Events (GEO-CAPE) Mission

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    Author Posting. ¬© American Meteorological Society, 2012. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Bulletin of the American Meteorological Society 93 (2012): 1547‚Äď1566, doi:10.1175/BAMS-D-11-00201.1.The Geostationary Coastal and Air Pollution Events (GEO-CAPE) mission was recommended by the National Research Council's (NRC's) Earth Science Decadal Survey to measure tropospheric trace gases and aerosols and coastal ocean phytoplankton, water quality, and biogeochemistry from geostationary orbit, providing continuous observations within the field of view. To fulfill the mandate and address the challenge put forth by the NRC, two GEO-CAPE Science Working Groups (SWGs), representing the atmospheric composition and ocean color disciplines, have developed realistic science objectives using input drawn from several community workshops. The GEO-CAPE mission will take advantage of this revolutionary advance in temporal frequency for both of these disciplines. Multiple observations per day are required to explore the physical, chemical, and dynamical processes that determine tropospheric composition and air quality over spatial scales ranging from urban to continental, and over temporal scales ranging from diurnal to seasonal. Likewise, high-frequency satellite observations are critical to studying and quantifying biological, chemical, and physical processes within the coastal ocean. These observations are to be achieved from a vantage point near 95¬į‚Äď100¬įW, providing a complete view of North America as well as the adjacent oceans. The SWGs have also endorsed the concept of phased implementation using commercial satellites to reduce mission risk and cost. GEO-CAPE will join the global constellation of geostationary atmospheric chemistry and coastal ocean color sensors planned to be in orbit in the 2020 time frame.Funding for GEO-CAPE definition activities is provided by the Earth Science Division of the National Aeronautics and Space Administration.2013-04-0

    Towards a muon collider

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    A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders design, physics and detector studies. The aim is to provide a global perspective of the field and to outline directions for future work

    The James Webb Space Telescope Mission

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    Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4m4m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5m6.5m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

    Consolidated arc design baseline: Milestone M2.5

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    Report on the collider arc design and its key elements considering the cumulative findings of all studies carried out so far, usable as input for the preparation of the Conceptual Design Report

    Preliminary arc design including optimized and integrated lattice deck: Deliverable D2.5

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    Annotated beam optics and lattice files with specifications of the required magnet parameters (strengths and apertures) including consolidated position and element characteristics. Specification of the required magnet types and quantities including magnet field quality specifications

    Lattice design of pp collider

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    International audienceA long list of optics and beam dynamics challenges for pp colliders includes the following: design of the interaction region with a low beta function; beam-beam effects; impedance, HOM losses and instabilities; achieving the dynamic aperture required for adequate beam lifetime, comprising the optimization of the arc optics; emittance control, including alignment and field errors, lattice nonlinearities, as well as beam-beam effects; machine protection, with dedicated halo cleaning section; injection and extraction of the beam. The lattice design has to handle these different challenges; the optimization is then multi-criteria like the machine performance or the machine cost. We will then consider here a few aspects of the lattice design like the arc optimization, some insertions like the interaction region or the beam cleaning insertions and how to tune the different regions together. To illustrate the problematics, we will use some examples coming from LHC [1], HL-LHC [2] or FCC-hh [3]

    Preliminary arc optics and lattice files: Milestone M2.2

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    This document describes the organisation of the optics file repository, how it can be accessed and explains, how the configuration is managed

    Analysis of electron cloud effects and mitigation options: Milestone M2.4

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    Report on the results of the electron cloud effects studies using computer simulations, considering different geometric designs of beam pipe, different surface treatments and different beam configurations. Assessment of coming to a workable system for a preferred set of working points and resulting requirements and constraints on the overall collider design
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