• I. Efthymiopoulos, K. Cornelis, A. Ferrari, E. Gschwendtner, Y. Kadi, A. Masi, A. Pardons, H. Vincke, J. Wenninger
  CERN, Geneva
• D. Autiero
  IN2P3 IPNL, Villeurbanne
• A. Guglielmi
  INFN/LNL, Legnaro (PD)
• P.R. Sala
  Istituto Nazionale di Fisica Nucleare, Milano

The CNGS facility (CERN Neutrinos to Gran Sasso) aims at directly detecting muon-neutrino to tau-neutrino oscillations. An intense muon-neutrino beam (10¹⁷ muon-neutrino per day) is generated at CERN and directed over 732 km towards the Gran Sasso National Laboratory, LNGS, in Italy, where two large and complex detectors, OPERA and ICARUS, are located. After a brief overview of the facility, the major events since its commissioning in 2006 will be discussed. Emphasis will be given on the design challenges and operation constraints coupled to such a high-intensity facility summarizing the acquired experience. Highlights of the 2008 operations, which was the first complete year of physics in CNGS with 1.78·10¹⁹ protons delivered on target, will be presented.

• E.H.M. Wildner, F. Cerutti, A. Ferrari, A. Mereghetti, E. Todesco
  CERN, Geneva
• F. Broggi
  INFN/LASA, Segrate (MI)

Recent studies show that the energy deposition for the LHC phase one luminosity upgrade, aiming at a peak luminosity 2.5 10³⁴ cm^-2s^-1, can be handled by appropriate shielding. The phase II upgrade aims at a further increase of a factor 4, possibly using Nb3Sn quadrupoles. This paper describes how the main features of the triplet layout, such as quadrupole lengths, gaps between magnets, and aperture, affect the energy deposition in the insertion. We show the dependence of the triplet lay-out on the energy deposition patterns in the insertion magnets. An additional variable which is taken into account is the choice of conductor, i.e. solutions with Nb-Ti and Nb3Sn are compared. Nb3Sn technology gives possibilities for increasing the magnet apertures and space for new shielding solutions. Our studies give a first indication on the possibility of managing energy deposition for the phase II upgrade.

• L. Lari
  EPFL, Lausanne
• R.W. Assmann, M. Brugger, F. Cerutti, A. Ferrari, L. Lari, V. Vlachoudis
  CERN, Geneva
• Th. Weiler
  KIT, Karlsruhe

Due to the known limitations of Phase I LHC collimators in stable physics conditions, the LHC collimation system will be complemented by additional 30 Phase II collimators. The Phase II collimation system is designed to improve cleaning efficiency and to minimize the collimator-induced impedance with the main function of protecting the Super Conducting (SC) magnets from quenching due to beam particle losses. To fulfil these requirements, different possible innovative collimation designs were taken in consideration. Advanced jaw materials, including new composite materials (e.g. Cu–Diamond), jaw SiC insertions, coating foil, in-jaw instrumentation (e.g. BPM) and improved mechanical robustness of the jaw are the main features of these new promising Phase II collimator designs developed at CERN. The FLUKA Monte Carlo code is extensively used to evaluate the behavior of these collimators in the most radioactive areas of LHC, supporting the mechanical integration. These studies aim to identify the possible critical points along the IR7 line.

• F. Cerutti, F. Borgnolutti, A. Ferrari, A. Mereghetti, E.H.M. Wildner
  CERN, Geneva

While the Large Hadron Collider (LHC) at CERN is starting operation with beam, aiming to achieve nominal performance in the shortest term, the upgrade of the LHC interaction regions is actively pursued in order to enhance the physics reach of the machine. Its first phase, with the target of increasing the LHC luminosity to 2-3 10³⁴ cm^-2 s^-1, relies on the mature Nb-Ti superconducting magnet technology and is intended to maximize the use of the existing infrastructure. The impact of the increased power of the collision debris has been investigated through detailed energy deposition studies, considering the new aperture requirements for the low-beta quadrupoles and a number of other elements in the insertions. Effective solutions in terms of shielding options and design/layout optimization have been envisaged and the crucial factors have been pointed out.

• M.D. Salt
  UMAN, Manchester
• R. Appleby, K. Elsener
  CERN, Geneva
• A. Ferrari
  Uppsala University, Uppsala

The CLIC beam delivery system focuses 1.5 TeV electron and positron beams to a nanometre-sized cross section when colliding them at the interaction point (IP). The intense focusing leads to large beam-beam effects, causing the production of beamstrahlung photons, coherent and incoherent electron-positron pairs, as well as a significant disruption of the main beam. The transport of the post-collision beams requires a minimal loss extraction line, with high acceptance for energy deviation and divergence. The current design includes vertical bends close to the IP in order to separate the charged particles with a sign opposite to the main beam into a diagnostic-equipped intermediate dump, whilst transporting the photons and the main beam to the main dump. Photon and charged particle losses on the collimators and dumps result in a complex radiation field and IP background particle fluxes. In this paper, the electromagnetic backgrounds at the IP, which arise from these losses, are calculated, and the potential impact on the detector is discussed.

• F. Stulle, L. Rinolfi, D. Schulte
  CERN, Geneva
• A. Ferrari
  Uppsala University, Uppsala
• A. Latina
  Fermilab, Batavia

Prior to acceleration in the main linac, the particle beams created in the centrally located injector have to be transported to the outer ends of the CLIC site. This transport should not only preserve the beam quality but also shape, characterize and tune the phase space distribution to match the requirements at the entrance of the main linac. Hence, the performance of the transport downstream of the damping rings up to the main linac, the so called RTML, is crucial for the overall performance of CLIC. The RTML consists of a variety of components like bunch compressors, accelerating cavities, spin rotators, collimators, diagnostics sections, feedback and feedforward systems, each serving a distinct function. We discuss the different parts of the RTML and the beam dynamics challenges connected to them. Their status is outlined and results of beam dynamics simulations are presented.