Author: Nagaoka, R.
Paper Title Page
MOPWA011 The Damping of Transverse Coherent Instabilities by Harmonic Cavities 102
 
  • F.J. Cullinan, R. Nagaoka
    SOLEIL, Gif-sur-Yvette, France
  • G. Skripka, P.F. Tavares
    MAX-lab, Lund, Sweden
 
  At nonzero chromaticity, the threshold current due to transverse coupled bunch instabilities in an electron storage ring is defined by intrabunch head-tail motion of higher than zeroth order. Multibunch tracking simulations predict that this threshold can be increased to several times its original value through the introduction of bunch lengthening harmonic cavities. One previously suggested explanation is the narrower spectra of the elongated bunches but reliable estimates for the threshold currents are not obtainable for anything other than rigid beam motion since the usual Sacherer formulism is not directly applicable to beams in a non-harmonic potential. A new scheme has been developed in which the decay time of a higher than zeroth order transverse head-tail mode may be estimated by taking into account the synchrotron tune spread generated by the harmonic cavity potential. This scheme is presented along with the results of numerical simulations performed in order to confirm the analytical predictions and justify the assumptions made. The extension of the scheme to more complex scenarios is also discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA011  
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MOPWA012 Study of Optimal MBA Lattice Structures for the SOLEIL Upgrade 106
 
  • R. Nagaoka, P. Brunelle, F.J. Cullinan, X.N. Gavaldà, A. Loulergue, A. Nadji, L.S. Nadolski, M.-A. Tordeux
    SOLEIL, Gif-sur-Yvette, France
 
  Within the context of a future upgrade of the SOLEIL ring, a series of lattice studies has been made with the aim of reducing the current 4 nm-rad horizontal emittance ex by more than an order of magnitude, with a dynamic aperture allowing off-axis injection. As in most upgrades, the important constraint imposed is to keep all the existing straight sections and photon source points. A particularity of SOLEIL are the short straight sections in half of the 16 double-bend cells, created in between the dipoles, which limits the number of dipoles in a MBA cell. In the previous studies, a combination of 5- and 4BA was followed, where with the use of longitudinal gradient bends (LGBs), ex ~440 pm-rad was obtained. The present paper reports on studies extended along the same strategy: In particular, the feasibility and the attainable ex are pursued with a combination of 7- and 6BA, by employing dipoles with transverse gradient and LGBs. In addition, the effectiveness of a few known nonlinear optimization methods, such as the resonance driving term cancellation, interleaved sextupoles with proper phases, and genetic algorithm-based numerical searches shall be explored.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA012  
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TUPWA011 Progress on the LUNEX5 project 1416
 
  • M.-E. Couprie, C. Benabderrahmane, P. Berteaud, C. Bourassin-Bouchet, F. Bouvet, J.D. Bozek, F. Briquez, L. Cassinari, L. Chapuis, J. Da Silva, J. Daillant, Y. Dietrich, M. Diop, J.P. Duval, M.E. El Ajjouri, T.K. El Ajjouri, C. Herbeaux, N. Hubert, M. Khojoyan, M. Labat, P. Lebasque, N. Leclercq, A. Lestrade, A. Loulergue, P. Marchand, O. Marcouillé, J.L. Marlats, F. Marteau, C. Miron, P. Morin, A. Nadji, R. Nagaoka, F. Polack, F. Ribeiro, J.P. Ricaud, P. Rommeluère, P. Roy, G. Sharma, K.T. Tavakoli, M. Thomasset, M. Tilmont, S. Tripathi, M. Valléau, J. Vétéran, W. Yang, D. Zerbib
    SOLEIL, Gif-sur-Yvette, France
  • S. Bielawski, C. Evain
    PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
  • B. Carré, D. Garzella
    CEA/DSM/DRECAM/SPAM, Gif-sur-Yvette, France
  • X. Davoine
    CEA/DAM/DIF, Arpajon, France
  • N. Delerue
    LAL, Orsay, France
  • G. Devanz, C. Madec, A. Mosnier
    CEA/IRFU, Gif-sur-Yvette, France
  • A. Dubois, J. Lüning
    CCPMR, Paris, France
  • G. Lambert, V. Malka, A. Rousse, C. Thaury
    LOA, Palaiseau, France
  • E. Roussel
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • C. Szwaj
    PhLAM/CERLA, Villeneuve d'Ascq, France
 
  LUNEX5 (free electron Laser Using a New accelerator for the Exploitation of X-ray radiation of 5th generation) aims at investigating the production of short, intense, coherent Free Electron Laser (FEL) pulses in the 40-4 nm spectral range. It comprises a 400 MeV superconducting Linear Accelerator for high repetition rate operation (10 kHz), multi-FEL lines and adapted for studies of advanced FEL schemes, a 0.4 - 1 GeV Laser Wake Field Accelerator (LWFA) for its qualification by a FEL application, a single undulator line enabling advanced seeding and pilot user applications. Different studies such as on two color FEL and R&D programs have been launched. A test experiment for the demonstration of 180 MeV LWFA based FEL amplification at 200 nm is under preparation in collaboration with the Laboratoire d’Optique Appliquée, thanks to a proper electron beam manipulation. Specific hardware is also under development such as a cryo-ready 3 m long undulator of 15 mm period.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA011  
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TUPWA012 SOLEIL Status Report 1419
 
  • A. Nadji, Y.-M. Abiven, F. Bouvet, P. Brunelle, A. Buteau, N. Béchu, L. Cassinari, M.-E. Couprie, X. Delétoille, C. Herbeaux, N. Hubert, N. Jobert, M. Labat, J.-F. Lamarre, P. Lebasque, A. Lestrade, A. Loulergue, P. Marchand, O. Marcouillé, J.L. Marlats, L.S. Nadolski, R. Nagaoka, P. Prigent, K.T. Tavakoli, M.-A. Tordeux, M. Valléau
    SOLEIL, Gif-sur-Yvette, France
 
  The 2.75 GeV synchrotron light source SOLEIL (France) delivers photons to 27 beamlines and 2 new ones are under construction. The commissioning of the Femtoslicing operation mode involving two beamlines is in progress. The uniform filling pattern is now available to users with a 500 mA stored beam current. The operation of the two canted and long beamlines ANATOMIX and Nanoscopium both using in-vacuum insertion devices (IDs) as a photon source has been raising challenges still under investigation. Upgrades of crucial subsystem equipment like magnet power supplies, storage ring RF input power couplers, and solid state amplifiers are continuing. New user requests for beam stability are under upgrade consideration. Other projects for the storage ring are ongoing such as the design and construction of new insertion devices, new multipole injection kicker, localised small and round photon beam production, as well as R&D on 500 MHz solid-state amplifiers. In parallel first studies for a future upgrade of the machine have been progressing.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA012  
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