• B. Goddard, I.V. Agapov, E. Carlier, L. Ducimetière, E. Gallet, M. Gyr, L.K. Jensen, O.R. Jones, V. Kain, T. Kramer, M. Lamont, M. Meddahi, V. Mertens, T. Risselada, J.A. Uythoven, J. Wenninger, W.J.M. Weterings
  CERN, Geneva

Initial commissioning of the LHC beam dump system with beam took place in August and September 2008. The preparation, setting-up and the tests performed are described together with results of the extractions of beam into the dump lines. Analysis of the first detailed aperture measurements of extraction channels and kicker performance derived from dilution sweep shapes are presented. The performance of the other equipment subsystems is summarised, in particular that of the dedicated dump system beam instrumentation.

• R.J. Steinhagen, A. Boccardi, E. Calvo Giraldo, M. Gasior, J.L. Gonzalez, O.R. Jones
  CERN, Geneva

Until now, the continuous monitoring of the LHC lattice has been considered as impractical due to tight constraints on the maximum allowed beam excitations and acquisition time usually required for betatron function measurements. As an further exploitation of the Base-Band-Tune (BBQ) detection principle, already widely used for tune diagnostic, a real-time beta-beat measurement prototype has been successfully tested at the CERN SPS based on the continuous measurement of the cell-to-cell betatron phase advance. Tests show that the phase resolutions is better than a degree corresponding to a peak-to-peak beta-beat resolution of about one percent. Due to the system's high sensitivity it required only micro-metre range excitation, making it compatible with nominal LHC operation. This contribution discusses results, measurement systematics and possible additional exploitation that may be used to improve the nominal LHC performance.

• K. Fuchsberger, S.D. Fartoukh, B. Goddard, O.R. Jones, V. Kain, M. Meddahi, V. Mertens, J. Wenninger
  CERN, Geneva

The 3 km long TI 8 transfer line is used to transfer 450 GeV proton and ion beams from the SPS to LHC collider. As part of a detailed optics investigation program the chromaticity of the transfer line was measured. Kick response data of the transfer line was recorded for various extraction energy offsets in the SPS. The quadrupolar and sextupolar field errors over the whole transfer line dipoles, a systematic error of the main quadrupole strengths and the initial momentum error were estimated by a fit. Using the updated model, the chromaticity of the line was then calculated.

• B. Salvant
  EPFL, Lausanne
• D. Alesini, M. Migliorati, B. Spataro
  INFN/LNF, Frascati (Roma)
• G. Arduini, C. Boccard, F. Caspers, A. Grudiev, O.R. Jones, E. Métral, G. Rumolo, B. Salvant, C. Zannini
  CERN, Geneva
• R. Calaga
  BNL, Upton, Long Island, New York
• F. Roncarolo
  UMAN, Manchester

A detailed knowledge of the beam coupling impedance of the CERN Super Proton Synchrotron (SPS) is required in order to operate this machine with a higher intensity for the foreseen Large Hadron Collider (LHC) luminosity upgrade. A large number of Beam Position Monitors (BPM) is currently installed in the SPS, and this is why their contribution to the SPS impedance has to be assessed. This paper focuses on electromagnetic simulations and bench measurements of the longitudinal and transverse impedance generated by the horizontal and vertical BPMs installed in the SPS machine.