• F. Poirier, I. Chaikovska, O. Dadoun, P. Lepercq, R. Roux, A. Variola
  LAL, Orsay
• R. Boni, S. Guiducci, M.A. Preger, P. Raimondi
  INFN/LNF, Frascati (Roma)
• R. Chehab
  IN2P3 IPNL, Villeurbanne

Providing a high quality and sufficient high current positron beam for the ultra high luminosity B-factory SuperB is a major goal. In this paper a proposition for positrons production and capture scheme based on low energy electrons up to1 GeV is presented. For this technique, several types of flux concentrator used to capture the positrons are being studied. The following accelerating section bringing the positrons up to 280 MeV and the total yield for L-band and S-band type accelerators are given. Also the result of the benchmark between ASTRA and a LAL code based on Geant4 toolkit simulation is discussed.

• H. Fujimori, Z. Igarashi, Y. Irie, Y. Sato, M.J. Shirakata, I. Sugai, A. Takagi, Y. Takeda
  KEK, Ibaraki

The carbon stripping foil is the key element for the high-intensity proton accelerator. At KEK, the foil test system using the 650keV H^- Cockcroft-Walton accelerator is in operation, which can simulate the energy depositions to the foil with the same amount in the J-PARC. In order to quantatively observe the foil degradations (such as foil thinning, pin-hole production) during irradiation, online energy and particle analyzing system is under construction. This report outlines the design detail of the analyzing system including the detectors.

• A.V. Bondarenko, S.V. Miginsky, N. Vinokurov
  BINP SB RAS, Novosibirsk

A new beam extraction scheme from a synchrotron is put forward. The main difference from other schemes of extraction is the use of a magnetic shields instead of a septum. Magnetic shields are located in the central dipole magnets of a pulsed chicane. The magnetic shield is a multi-layer copper-iron tube. Numerical simulations and experimental results for the magnetic shield are presented. A good accordance between them has shown. The advantages of the new scheme are easy technical implementation and compactness. The area of application is extraction from a synchrotron. The proposed scheme will be used in a new synchrotron radiation source in Novosibirsk.

• J.A. Uythoven, E. Carlier, L. Ducimetière, B. Goddard, V. Kain, N. Magnin
  CERN, Geneva

The LHC beam dump system was commissioned with beam in 2009. This paper describes the operational experience with the kicker systems and the tests and measurements to qualify them for operation. The kicker performance was characterized with beam by measurements of the kicker waveforms using bunches extracted at different times along the kicker sweep. The kicker performance was also continuously monitored for each pulse with measurement and analysis of each kick pulse, allowing diagnostic of errors and of long-term drifts. The results are described and compared to the expectations.

• T. Kramer
  EBG MedAustron, Wr. Neustadt
• W. Bartmann, C. Bracco, B. Goddard, M. Meddahi
  CERN, Geneva

The LHC beam dump system has to safely dispose all beams in a wide energy range of 450 GeV to 7 TeV. A 3 μs abort gap in the beam structure for the switch-on of the extraction kicker field ideally allows a loss free extraction under normal operating conditions. However, a low number of asynchronous beam aborts is to be expected from reliability calculations and from the first year's operational experience with the beam dump kickers. For such cases, MAD-X simulations including all optics and alignment errors have been performed to determine loss patterns around the LHC as a function of the position of the main protection elements in interaction region six. Special attention was paid to the beam load on the tungsten collimators which protect the triplets in the LHC experimental insertions, and the tracking results compared with semi-analytical numerical estimates. The simulations are also compared to the results of beam commissioning of these protection devices.

• B. Goddard, V. Kain, M. Meddahi
  CERN, Geneva

The beam profile screens in the long SPS to LHC transfer lines were used to measure with high precision the emittance growth arising from scattering. The effective thickness of the scatterer could be varied by adding thick Al2O3 fluorescent screens, with the emittance measurement made using very thin Ti OTR screens. The technique allows the intrinsic variation in the emittance from the injector chain to be factored out of the measurement, and was applied to Pb⁸²⁺ and protons, both with 450 GeV rigidity. The results are presented and the possible applications to the accurate benchmarking of nuclear interaction codes discussed.

• V. Kain, K. Fuchsberger, B. Goddard, D. Karadeniz, M. Meddahi, J. Wenninger
  CERN, Geneva

The tilt mismatch between the LHC and its transfer lines arises from the use of combined horizontal and vertical bends. The mismatch gives rise to several subtle optical effects, including a coupling at injection into the LHC which depends on the phase of the oscillation amplitude at the injection point. This coupling was observed for the first time in 2008, and in 2009 dedicated measurements were made. The results are described and compared with the expectations, and the operational implications detailed.

• B. Goddard, V. Baggiolini, W. Bartmann, C. Bracco, L.N. Drosdal, E.B. Holzer, V. Kain, D. Khasbulatov, N. Magnin, M. Meddahi, A. Nordt, M. Sapinski
  CERN, Geneva
• M. Vogt
  DESY, Hamburg

The quality of the injection into the LHC is monitored by a dedicated software system which acquires and analyses the pulse waveforms from the injection kickers, and measures key beam parameters and compares them with the nominal ones. The beam losses at injection are monitored on many critical devices in the injection regions, together with the longitudinal filling pattern and maximum trajectory offset on the first 100 turns. The paper describes the injection quality check system and the results from LHC beam commissioning, in particular the beam losses measured during injection at the various aperture limits. The results are extrapolated to full intensity and the consequences are discussed.

• B. Goddard, W. Bartmann, C. Bracco, V. Kain, M. Meddahi, V. Mertens, J.A. Uythoven
  CERN, Geneva

The commissioning of the beam transfer systems for LHC included detailed aperture measurements in the injection regions and for the beam dump systems. The measurements, mainly single pass, were made using systematic scans of different oscillation phases and amplitudes, and the results compared with the expectations from the physical aperture model of the LHC. In this paper the measurements and results are presented and compared with the specified apertures in these critical areas.

• M. Meddahi, S.D. Fartoukh, K. Fuchsberger, B. Goddard, W. Herr, V. Kain, V. Mertens, J. Wenninger
  CERN, Geneva
• D. Kaltchev
  TRIUMF, Vancouver

In 2008, the SPS-to-LHC transfer line operation allowed for the first time to perform beam measurements in the last part of the lines and into the LHC. Beam parameters were measured and compared with expectation. Discrepancies were observed in the dispersion matching into the LHC, and also in the vertical phase advance along the line. In 2009, extensive theoretical and simulation work was performed in order to understand the possible sources of these discrepancies. This allowed establishing an updated model of the beam line, taking into account the importance of the full magnetic model, the limited dipole corrector strengths and the precise alignment of beam elements. During 2009, beam time was allocated in order to perform further measurements, checking and refining the optical model of the transfer line and LHC injection region and validating the different assumptions. Results of the 2009 optics measurements and comparison with the beam specification and model are presented.