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Wildner, E. Y.

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MOPAN073 Parametric Study of Heat Deposition from Collision Debris into the Insertion Superconducting Magnets for the LHC Luminosity Upgrade 323
  • C. Hoa, F. Cerutti, J.-P. Koutchouk, G. Sterbini, E. Y. Wildner
    CERN, Geneva
  • F. Broggi
    INFN/LASA, Segrate (MI)
  With a new geometry in a higher luminosity environment, the power deposition in the superconducting magnets becomes a critical aspect to analyze and to integrate in the insertion design. In this paper, we quantify the power deposited in magnets insertion at variable positions from the interaction point (IP). A fine characterization of the debris due to the proton-proton collisions at 7 TeV, shows that the energetic particles in the very forward direction give rise to non intuitive dependences of the impacting energy on the magnet front face and inner surface. The power deposition does not vary significantly with the distance to the interaction point, because of counterbalancing effects of different contributions to power deposition. We have found out that peak power density in the magnet insertion does not vary significantly with or without the Target Absorber Secondaries (TAS) protection.  
MOPAN086 Final Geometry of 1232 LHC Dipoles 359
  • E. Y. Wildner, M. Bajko, P. Bestmann, S. D. Fartoukh, J. B. Jeanneret, D. P. Missiaen, D. Tommasini
    CERN, Geneva
  The 15 m long main dipoles for the Large Hadron Collider are now being installed in their final positions in the accelerator tunnel. Geometric measurements of the magnets after many of the production steps from industry to the cryostating, after cold tests and after preparation of the magnets for installation, have been made, permitting careful control of the shape of the magnet, the positioning of the field correctors, and the final positioning in the tunnel. The result of the geometry control at the different production stages, from industry to CERN, using different kinds of control procedures and analysis, will be reported.  
MOPAN087 Processing Magnet Geometry Measurements for Better Control of LHC Aperture 362
  • E. Y. Wildner, N. Emelianenko
    CERN, Geneva
  The axis of the Large Hadron Collider superconducting magnets are measured from both ends. These two redundant measurements are combined to get a reliable measurement result. When the two measurements are put together, we observe a 'saw tooth' effect due to the fact that the two measurements are, in general, not identical. This is expected from the accuracy of the two measurements. However the effect observed is larger than expected, in the vertical plane. Effects of temperature gradients in the cold bore tube during measurements have been observed and we show that this effect is the most probable explanation for the observations of the large differences in the measurements between the two sides. This work proposes an algorithmic approach to filter this effect to improve measurement results. Magnets are positioned with an accuracy of 0.1 mm, and the error in positioning coming from measurement errors due to the temperature effects can be up to 0.3 mm. Our analysis shows that by applying this correction we can insure the best positioning of the magnets in the tunnel in the vertical plane. Analysis is done for the 14 m long main dipoles, for which the effect is most visible.  
MOPAN088 A Large Aperture Superconducting Dipole for Beta Beams to Minimize Heat Deposition in the Coil 365
  • E. Y. Wildner, C. Vollinger
    CERN, Geneva
  The aim of "beta beams" in a decay ring is to produce highly energetic pure electron neutrino and anti-neutrino beams coming from b-decay of 18Ne10+ and 6He2+ ion beams. The decay products, having different magnetic rigidities than the ion beam, are deviated inside the dipole. The aperture and the length of the magnet have to be optimized to avoid that the decay products hit the coil. The decay products are intercepted by absorber blocks inside the beam pipe between the dipoles to protect the following dipole. A first design of a 6T arc dipole using a cosine theta layout of the coil with an aperture of 80 mm fulfils the optics requirements. Heat deposition in the coil has been calculated using different absorber materials to find a solution to efficiently protect the coil. Aspects of impedance minimization for the case of having the absorbers inside the beam pipe have also been addressed.  
MOPAN077 Geometry of the LHC Short Straight Sections Before Installation in the Tunnel: Resulting Aperture, Axis and BPM Positioning 335
  • D. P. Missiaen, P. Bestmann, M. C.L. Buzio, S. D. Fartoukh, M. Giovannozzi, J. B. Jeanneret, A. M. Lombardi, Y. Papaphilippou, S. Pauletta, J. C. Perez, H. Prin, E. Y. Wildner
    CERN, Geneva
  The Large Hadron Collider Short Straight Sections (SSS) are currently being installed in their final position in the accelerator tunnel. For all the SSSs, both those in the regular arcs as well as those in the insertion regions, magnetic and geometric measurements are made at different steps of their assembly. These stages range from production in the industry to the cryostating at CERN, as well as during and after cold tests or during installation of the BPM and the cold warm transition for the stand alone magnets. The results of the geometry at the various production stages by means of different procedures and analysis tools are reported and discussed in details in this paper.  
THPAN006 Simulation of Decays and Secondary Ion Losses in a Betabeam Decay Ring 3232
  • F. W. Jones
    TRIUMF, Vancouver
  • E. Y. Wildner
    CERN, Geneva
  The beta decay of circulating ions in the decay ring of a Betabeam facility will give rise to secondary ions which differ in charge from the primary ions and will follow widely off-momentum orbits. A small fraction of these ions will be lost in the long straights, but the great majority of them will be lost in the arcs. Profiling of the losses requires detailed knowledge of the paths of these ions, which are distributed in phase space as well as around the ring circumference. We describe here a comprehensive model of ion decay, secondary ion tracking, and loss detection, which has been implemented in the tracking and simulation code Accsim. Methods have been developed to accurately track ions at large momentum deviations not amenable to conventional multiparticle tracking codes, as well as to detect their impact coordinates on vacuum chamber walls (possibly inside magnetic elements). In our simulation we have also included absorbers which are needed, along with appropriate lattice optimisations, to localize the majority of losses outside of the dipoles. From simulation results, some estimates of decay ring performance (in terms of loss concentration and management) will be given.  
FROAKI01 Magnet Acceptance and Allocation at the LHC Magnet Evaluation Board 3739
  • L. Bottura, P. Bestmann, N. Catalan-Lasheras, S. D. Fartoukh, S. S. Gilardoni, M. Giovannozzi, J. B. Jeanneret, M. Karppinen, A. M. Lombardi, K. H. Mess, D. P. Missiaen, M. Modena, R. Ostojic, Y. Papaphilippou, P. Pugnat, S. Ramberger, S. Sanfilippo, W. Scandale, F. Schmidt, N. Siegel, A. P. Siemko, D. Tommasini, T. Tortschanoff, E. Y. Wildner
    CERN, Geneva
  The normal- and superconducting magnets for the LHC ring have been carefully examined to insure that each of the more than 1800 assemblies is suitable for the operation in the accelerator. Magnet coordinators, hardware experts and accelerator physicists, joined in the LHC Magnet Evaluation Board, have contributed to this work that consists in the magnet acceptance, and the optimisation achieved by sorting magnets according to their geometry, field quality and quench level. This paper gives a description of the magnet approval mechanism that has been running since four years, reporting in a concise summary on the main results achieved. We take as specific indicators the computed mechanical aperture, the sorting efficiency with respect to systematic and random field errors in the magnets, and the case-by-case analysis necessary to accommodate hardware limitations such as quench limits and training.  
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