• R. Calaga, R. De Maria
  BNL, Upton, Long Island, New York
• R.W. Assmann, J. Barranco, F. Caspers, E. Ciapala, T.P.R. Linnecar, E. Métral, Y. Sun, R. Tomás, J. Tuckmantel, Th. Weiler, F. Zimmermann
  CERN, Geneva
• G. Burt
  Lancaster University, Lancaster
• Y. Funakoshi, A. Morita, Y. Morita, K. Nakanishi, Y. Ohnishi
  KEK, Ibaraki
• Z. Li, A. Seryi, L. Xiao
  SLAC, Menlo Park, California
• P.A. McIntosh
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• J. Qiang
  LBNL, Berkeley, California
• N. Solyak, V.P. Yakovlev
  Fermilab, Batavia

Funding: This work was partially performed under the auspices of the US DOE and the European Community-Research Infrastructure, FP6 programme (CARE, contract number RII3-CT-2003-506395)}

The LHC crab cavity program is advancing rapidly towards a first prototype which is anticipated to be tested during the early stages of the LHC phase I upgrade and commissioning. Some aspects related to crab optics, collimation, aperture constraints, impedances, noise effects, beam transparency and machine protection critical for a safe and robust operation of LHC beams with crab cavities are addressed here.

Slides

• N. Solyak, T.J. Peterson, V. Poloubotko, V.P. Yakovlev
  Fermilab, Batavia
• O. Brunner, E. Ciapala, T.P.R. Linnecar, J. Tuckmantel, W. Weingarten
  CERN, Geneva
• R. Calaga
  BNL, Upton, Long Island, New York

Funding: This work has been partially performed under the auspices of the US department of energy

The complex LHC crab cavity design and the beam-line configuration pose very tight constraints for the cryostat design. An initial assessment of the LHC main RF cryostat points to a new design both from the RF and engineering point of view. The cavity and tunnel constraints are discussed in detail and an intial cryostat design along with the cryogenic circuit is presented.

• A.C. Butterworth, M. E. Angoletta, L. Arnaudon, P. Baudrenghien, J. Bento, T. Bohl, O. Brunner, E. Ciapala, F. Dubouchet, G. Hagmann, W. Höfle, T.P.R. Linnecar, P. Maesen, J.C. Molendijk, E. Montesinos, J. Noirjean, A.V. Pashnin, V. Rossi, J. Sanchez-Quesada, M. Schokker, E.N. Shaposhnikova, D. Stellfeld, J. Tuckmantel, D. Valuch, U. Wehrle, F. Weierud
  CERN, Geneva
• R. Sorokoletov
  JINR, Dubna, Moscow Region

Hardware commissioning of the LHC RF system was successfully completed in time for first beams in LHC in September 2008. All cavities ware conditioned to nominal field, power systems tested and all Low level synchronization systems, cavity controllers and beam control electronics were tested and calibrated. Beam was successfully captured in ring 2, cavities phased, and a number of initial measurements made. These results are presented and tests and preparation for colliding beams in 2009 are outlined.

• E.N. Shaposhnikova, T. Bohl, H. Damerau, K. Hanke, T.P.R. Linnecar, B. Mikulec, J. Tan, J. Tuckmantel
  CERN, Geneva

First reference measurements of the longitudinal impedance were made with beam in the SPS machine in 1999 to quantify the results of the impedance reduction programme, completed in 2001. The 2001 data showed that the low-frequency inductive impedance had been reduced by a factor 2.5 and that bunch lengthening due to the microwave instability was absent up to the ultimate LHC bunch intensity. Measurements of the quadrupole frequency shift with intensity in the following years suggest a significant increase in impedance (which nevertheless remains below the 1999 level) due to the installation of eight extraction kickers for beam transfer to the LHC. Microwave instability is still not observed up to the maximum bunch intensities available from injector. The experimental results are compared with expectations based on the known longitudinal impedance of the different machine elements in the SPS.

• F. Gerigk, M. Schuh, J. Tuckmantel
  CERN, Geneva
• C.P. Welsch
  KIP, Heidelberg

In this paper is analysed the influence of Higher Order Modes (HOM) on the operation of the superconducting linac section of the SPL, the Superconducting Proton Linac being designed at CERN. For this purpose, the characteristics of the HOMs in the 2 different beta families (0.65, 0.92 both at 704 MHz) of the SPL are calculated to estimate their effect on the cryogenic system and on the beam stability. For both criteria the maximum external Q of the HOMs is defined.

• F. Zimmermann, F. Bordry, H.-H. Braun, O.S. Brüning, H. Burkhardt, A.L. Eide, R. Garoby, B.J. Holzer, J.M. Jowett, T.P.R. Linnecar, K.H. Meß, J.A. Osborne, L. Rinolfi, D. Schulte, R. Tomás, J. Tuckmantel, A. Vivoli, A. de Roeck
  CERN, Geneva
• H. Aksakal
  N.U, Nigde
• S. Chattopadhyay, J.B. Dainton
  Cockcroft Institute, Warrington, Cheshire
• A.K. Çiftçi
  Ankara University, Faculty of Sciences, Tandogan/Ankara
• M. Klein
  The University of Liverpool, Liverpool
• T. Omori, J. Urakawa
  KEK, Ibaraki
• S. Sultansoy
  TOBB ETU, Ankara
• F.J. Willeke
  BNL, Upton, Long Island, New York

Sub-atomic physics at the energy frontier probes the structure of the fundamental quanta of the Universe. The Large Hadron Collider (LHC) at CERN opens for the first time the “terascale” (TeV energy scale) to experimental scrutiny, exposing the physics of the Universe at the sub-attometric (~10^-19 m, 10^-10 as) scale. The LHC will also take the science of nuclear matter to hitherto unparalleled energy densities (low-x physics). The hadron beams, protons or ions, in the LHC underpin this horizon, and also offer new experimental possibilities at this energy scale. A Large Hadron electron Collider, LHeC, in which an electron (positron) beam of energy (70 to 140 GeV) is in collision with one of the LHC hadron beams, makes possible terascale lepton-hadron physics. The LHeC is presently being evaluated in the form of two options, “ring-ring” and “linac-ring”, either of which operate simultaneously with pp or ion-ion collisions in other LHC interaction regions. Each option takes advantage of recent advances in radio-frequency, in linear acceleration, and in other associated technologies, to achieve ep luminosity as large as 10³³ cm^-2s^-1.

Slides