CERN Accelerating science

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AB-LHC@EPAC2008
46 items
last update: 08 Sep 2008, 16:26
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1.
Reliable Operation of the AC Dipole in the LHC / Tomás, R (CERN) ; Fartoukh, S (CERN) ; Serrano, J (CERN)
The AC dipole in the LHC will not only provide transverse oscillations without emittance growth but also with a safety guarantee. These two features are due to the adiabaticity of the excitation. [...]
LHC-PROJECT-Report-1095; CERN-LHC-PROJECT-Report-1095.- Geneva : CERN, 2008 - 4 p. Fulltext: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP026
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2.
Beam Scraping to detect and remove Halo in LHC Injection / Letnes, P A (CERN) ; Pedersen, S (CERN) ; Brielmann, A (CERN) ; Burkhardt, H (CERN) ; Kramer, Daniel (CERN)
Fast scrapers are installed in the SPS to detect and remove beam halo before extraction of beams to the LHC, to minimize the probability for quenching of superconducting magnets in the LHC. We shortly describe the current system and then focus on our recent work, which aims at providing a system which can be used as operational tool for standard LHC injection. [...]
LHC-PROJECT-Report-1096; CERN-LHC-PROJECT-Report-1096.- Geneva : CERN, 2008 - 4 p. Fulltext: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.THPC149
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3.
RF Wire Compensator of Long-Range Beam-Beam Effects / Dorda, U (TU. Vienna) ; Caspers, Friedhelm (CERN) ; Kroyer, T (CERN) ; Zimmermann, F (CERN)
The dynamic aperture of the proton beam circulating in the Large Hadron Collider (LHC) is expected to be limited by up to 120 long-range beam-beam encounters. In order to perfectly compensate the LHC long-range beambeam effect for nominal as well as for so-called "PACMAN" bunches, i.e. [...]
LHC-PROJECT-Report-1097; CERN-LHC-PROJECT-Report-1097.- Geneva : CERN, 2008 - 4 p. Fulltext: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.THPC081
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4.
Analysis of Optical Layouts for the Phase 1 upgrade of the CERN Large Hadron Collider Insertion Regions / Borgnolutti, F (CERN) ; Brüning, Oliver Sim (CERN) ; Dorda, U (CERN) ; Fartoukh, S (CERN) ; Giovannozzi, M (CERN) ; Herr, Werner (CERN) ; de Maria, R (CERN) ; Meddahi, M (CERN) ; Todesco, E (CERN) ; Tomás, R (CERN) et al.
In the framework of the studies for the upgrade of the insertions of the CERN Large Hadron Collider, four optical layouts were proposed with the aim of reducing the beta-function at the collision point down to 25 cm. The different candidate layouts are presented. [...]
LHC-PROJECT-Report-1098; CERN-LHC-PROJECT-Report-1098.- Geneva : CERN, 2008 - 4 p. Fulltext: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP012
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5.
Effects of Ultraperipheral Nuclear Collisions in the LHC and their Alleviation / Bruce, R (CERN ; MAX-lab Lund U.) ; Gilardoni, S (CERN) ; Jowett, M J (CERN)
Electromagnetic interactions between colliding heavy ions at the LHC are the sources of specific beam loss mechanisms that may quench superconducting magnets. We propose a simple yet efficient strategy to alleviate the effect of localized losses from bound-free pair production by spreading them out in several magnets by means of orbit bumps [...]
LHC-PROJECT-Report-1099; CERN-LHC-PROJECT-Report-1099.- Geneva : CERN, 2008 - 4 p. Fulltext: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP006
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6.
Longitudinal stability of Flat Bunches with Space-Charge or Inductive Impedance / Santiago Gonzalez, I (CERN) ; Zimmermann, F (CERN)
We study the loss of Landau damping for the longitudinal plane via the "Sacherer formalism". Stability limits are calculated for several longitudinal beam distributions, in particular for two types of flat bunches, which could be of interest to the LHC upgrade. [...]
LHC-PROJECT-Report-1100; CERN-LHC-PROJECT-Report-1100.- Geneva : CERN, 2008 - 4 p. Fulltext: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.TUPP082
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7.
Electron-Cloud Intrabunch Density Modulation / Zimmermann, F (CERN) ; Franchetti, G (GSI Darmstadt Germany)
During the passage of a proton bunch through an electron cloud, a complicated electron density modulation arises, with characteristic ring or stripe patterns that move radially outward along the bunch. We present simulation results for field-free and dipole regions, which reveal the morphology and main features of this phenomenon, explain the physical origin of the stripes in either case, and discuss the dependence on key parameters..
LHC-PROJECT-Report-1101; CERN-LHC-PROJECT-Report-1101.- Geneva : CERN, 2008 - 4 p. Fulltext: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.THPC089
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8.
Wire excitation experiments in the CERN SPS / Dorda, U (TU. Vienna) ; Calaga, R (BNL Upton USA) ; Fischer, W (BNL Upton USA) ; Koutchouk, Jean-Pierre (CERN) ; Tomás, R (CERN) ; Wenninger, J (CERN) ; Zimmermann, F (CERN)
In order to study the effect of long range interaction and its wire compensation experimentally, current carrying wires are installed in the CERN Super Proton Synchrotron (SPS). In this paper we summarize the main results of the 2007 wire excitation experiments at 26, 37 and 55 GeV including scans of wire current, beam-wire distance and chromaticity [...]
LHC-PROJECT-Report-1102; CERN-LHC-PROJECT-Report-1102.- Geneva : CERN, 2008 - 4 p. Fulltext: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.THPC082
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9.
Non-linear correction schemes for the Phase 1 LHC Insertion Region Upgrade and Dynamic Aperture studies / Tomás, R (CERN) ; Giovannozzi, M (CERN) ; de Maria, R (CERN)
The Phase 1 LHC Interaction Region (IR) upgrade aims at increasing the machine luminosity essentially by reducing the beam size at the Interaction Point (IP). This requires a total redesign of the full IR. [...]
LHC-PROJECT-Report-1103; CERN-LHC-PROJECT-Report-1103.- Geneva : CERN, 2008 - 4 p. Fulltext: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP024
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10.
Comparison between Laboratory Measurements, Simulations and Analytical Predictions of the Resistive Wall Transverse Beam Impedance at low frequencies / Roncarolo, F (Manchester U. ; Cockcroft Inst.) ; Caspers, Friedhelm (CERN) ; Kroyer, T (CERN) ; Métral, E (CERN) ; Salvant, B (EPFL, Lausanne)
The prediction of the resistive wall transverse beam impedance at the first unstable betatron line (8 kHz) of the CERN Large Hadron Collider (LHC) is of paramount importance for understanding and controlling the related coupled-bunch instability. Until now only novel analytical formulas were available at this frequency. [...]
LHC-PROJECT-Report-1104; CERN-LHC-PROJECT-Report-1104.- Geneva : CERN, 2008 - 4 p. Fulltext: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.TUPP061
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11.
Bench measurements of the Low Frequency Transverse Impedance of the CERN LHC Beam Vacuum Interconnects with RF Contacts / Salvant, B (EPFL, Lausanne) ; Caspers, Friedhelm (CERN) ; Kroyer, T (CERN) ; Métral, E (CERN) ; Roncarolo, F (University of Manchester and Cockcroft Institute England)
The low frequency longitudinal and transverse impedances of the CERN Large Hadron Collider (LHC) have to be specifically minimized to prevent the onset of coherent instabilities. The LHC beam vacuum interconnects were designed as Plug In Modules (PIMs) with RF contacts to reduce their coupling impedances, but the resulting contact resistance is a concern, as this effect is difficult to estimate. [...]
LHC-PROJECT-Report-1105; CERN-LHC-PROJECT-Report-1105.- Geneva : CERN, 2008 - 4 p. Fulltext: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.TUPP068
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12.
Optics Flexibility in the LHC at Top Energy / Aiba, M (CERN) ; Burkhardt, H (CERN) ; Fartoukh, S (CERN) ; Giovannozzi, M (CERN) ; White, S (CERN)
Flexibility of the LHC optics at top energy has been studied, in terms of betatron tune tunability, mainly for the high-beta optics that requires tunability of the order of half a unit. It has been shown that the tunability at top energy is good enough for the high-beta optics. [...]
LHC-PROJECT-Report-1106; CERN-LHC-PROJECT-Report-1106.- Geneva : CERN, 2008 - 4 p. Fulltext: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP003
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13.
Measurement and Effects of the Magnetic Hysteresis on the LHC Crossing Angle and Separation Bumps / Sammut, N J (Malta U. ; CERN) ; White, S M (CERN) ; Burkhardt, H (CERN) ; Giloux, C (CERN) ; Venturini-Delsolaro, W (CERN)
The superconducting orbit corrector magnets (MCBC, MCBY and MCBX) in the Large Hadron Collider (LHC) at CERN will be used to generate parallel separation and crossing angles at the interaction points during the different phases that will bring the LHC beams into collision. However, the field errors generated by the inherent hysteresis in the operation region of the orbit correctors may lead to unwanted orbit perturbations that could have a critical effect on luminosity. [...]
LHC-PROJECT-Report-1107; CERN-LHC-PROJECT-Report-1107; LHC-PROJECT-Report-1150; CERN-LHC-PROJECT-Report-1150.- Geneva : CERN, 2008 - 4 p. Fulltext: LHC-PROJECT-REPORT-1107_2 - PDF; LHC-PROJECT-REPORT-1107 - PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP005
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14.
Optics Correction in the LHC / Aiba, M (CERN) ; Calaga, R (BNL USA) ; Morita, A (KEK Japan) ; Tomás, R (CERN) ; Vanbavinckhove, G (CERN)
Optics correction in the LHC is challenged by the tight aperture constrains and the demand of a highly performing BPM system. To guarantee that the LHC optics remains within a maximum allowable beta-beating of 20% several methods are being investigated through computer simulations and experiments at existing hadron machines. [...]
LHC-PROJECT-Report-1108; CERN-LHC-PROJECT-Report-1108.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP025
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15.
Measurements of heavy ion beam losses from collimation / Bruce, R (CERN) ; Assmann, R W (CERN) ; Bellodi, G (CERN) ; Bracco, C (CERN) ; Braun, H H (CERN) ; Gilardoni, S (CERN) ; Holzer, E B (CERN) ; Jowett, John M (CERN) ; Redaelli, S (CERN) ; Weiler, T (CERN) et al.
The collimation efficiency for Pb ion beams in the LHC is predicted to be lower than requirements. Nuclear fragmentation and electromagnetic dissociation in the primary collimators create fragments with a wide range of Z/A ratios, which are not intercepted by the secondary collimators but lost where the dispersion has grown sufficiently large. [...]
LHC-PROJECT-Report-1109; CERN-LHC-PROJECT-Report-1109.- Geneva : CERN, 2008 - 4 p. APS Published version, local copy: PDF; Fulltext: LHC-PROJECT-REPORT-1109_2 - PDF; LHC-PROJECT-REPORT-1109 - PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEOAG02
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16.
Upgrade Issues for the CERN Accelerator Complex / Garoby, R (CERN)
The Large Hadron Collider (LHC) at CERN is at a very advanced stage of hardware commissioning and the first beam collisions in the experiments are expected during the year 2008. In line with the recommendations issued in 2006 by the European Strategy Group for Particle Physics, work has now started for maximizing the physics reach of the LHC and for preparing for other foreseeable needs. [...]
LHC-PROJECT-Report-1110; CERN-LHC-PROJECT-Report-1110.- Geneva : CERN, 2008 - 6 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.FRYAGM01
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17.
Electron Cooling Experiments at LEIR / Tranquille, G (CERN)
The LEIR electron cooler is the first of a new generation of coolers utilising high-perveance variable-density electron beams for the cooling and accumulation of heavy ion beams. It was commissioned at the end of 2005 and has since been routinely used to provide high brightness Pb ion beams required for future LHC ion runs. [...]
LHC-PROJECT-Report-1111; CERN-LHC-PROJECT-Report-1111.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.THPP057
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18.
Cooled Beam Diagnostics on LEIR / Tranquille, G (CERN) ; Bal, C (CERN) ; Carli, C (CERN) ; Chanel, M (CERN) ; Prieto, V (CERN) ; Sautier, R (CERN) ; Tan, J (CERN)
Electron cooling is central in the preparation of dense bunches of lead beams for the LHC. Ion beam pulses from the LINAC3 are transformed into short highbrightness bunches using multi-turn injection, cooling and accumulation in the Low Energy Ion Ring, LEIR [1]. [...]
LHC-PROJECT-Report-1112; CERN-LHC-PROJECT-Report-1112.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.TUPC102
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19.
Aperture Restriction Localisation in the LHC Arcs using an RF Mole and the LHC Beam Position Measurement System / Albertone, J (CERN) ; Bartolome-Jimenez, S (CERN) ; Boccard, C (CERN) ; Bogey, T (CERN) ; Borowiec, P (Cracow, INP) ; Calvo, E (CERN) ; Caspers, Friedhelm (CERN) ; Gasior, M (CERN) ; González, J L (CERN) ; Jenninger, B (CERN) et al.
Ensuring that the two 27km beam pipes of the LHC do not contain aperture restrictions is of utmost importance. Most of the ring is composed of continuous cryostats, so any intervention to remove aperture restrictions when the machine is at its operating temperature of 1.9K will require a substantial amount of time. [...]
LHC-PROJECT-Report-1113; CERN-LHC-PROJECT-Report-1113.- Geneva : CERN, 2008 - 3 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP056
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20.
Preliminary Exploratory Study of Different Phase II Collimators / Lari, L (EPFL-LPHE, Lausanne ; CERN) ; Assmann, Ralph Wolfgang (CERN) ; Bertarelli, A (CERN) ; Bracco, C (EPFL-LPHE, Lausanne ; CERN) ; Brugger, M (CERN) ; Cerutti, F (CERN) ; Dallocchio, Alessandro (CERN) ; Doyle, E (SLAC) ; Ferrari, A (CERN) ; Keller, L (SLAC) et al.
The LHC collimation system is installed and commissioned in different phases, following the natural evolution of the LHC performance. To improve cleaning efficiency towards the end of the low beta squeeze at 7TeV, and in stable physics conditions, it is foreseen to complement the 30 highly robust Phase I secondary collimators with low impedance Phase II collimators. [...]
LHC-PROJECT-Report-1114; CERN-LHC-PROJECT-Report-1114.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP071
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21.
Evaluation of Beam Losses and Energy Depositions for a Possible Phase II Design for LHC Collimation / Lari, L (EPFL-LPHE, Lausanne ; CERN) ; Assmann, Ralph Wolfgang (CERN) ; Bracco, C (EPFL-LPHE, Lausanne ; CERN) ; Brugger, M (CERN) ; Cerutti, F (CERN) ; Doyle, E (SLAC) ; Ferrari, A (CERN) ; Keller, L (SLAC) ; Lundgren, S (SLAC) ; Keller, L (SLAC) et al.
The LHC beams are designed to have high stability and to be stored for many hours. The nominal beam intensity lifetime is expected to be of the order of 20h. [...]
LHC-PROJECT-Report-1115; CERN-LHC-PROJECT-Report-1115.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP072
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22.
Emittance Growth at LHC Injection from SPS and LHC Kicker Ripple / Kotzian, G (CERN) ; Barnes, M (CERN) ; Ducimetière, L (CERN) ; Goddard, B (CERN) ; Höfle, Wolfgang (CERN)
Fast pulsed kicker magnets are used to extract beams from the SPS and inject them into the LHC. The kickers exhibit time-varying structure in the pulse shape which translates into small offsets with respect to the closed orbit at LHC injection. [...]
LHC-PROJECT-Report-1116; CERN-LHC-PROJECT-Report-1116.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.THPP113
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23.
Study of Controlled Longitudinal Emittance Blow-Up for High Intensity LHC Beams in the CERN SPS / Papotti, G (CERN) ; Bohl, T (CERN) ; Linnecar, T (CERN) ; Shaposhnikova, E (CERN) ; Tückmantel, Joachim (CERN)
Preventive longitudinal emittance blow-up, in addition to a fourth harmonic Landau damping RF system, is required to keep the LHC beam in the SPS stable up to extraction. The beam is blown-up in a controlled way during the acceleration ramp by using band-limited phase noise targeted to act inside the synchrotron frequency spread, which is itself modified both by the second RF system and by intensity effects (beam loading and others). [...]
LHC-PROJECT-Report-1117; CERN-LHC-PROJECT-Report-1117.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.TUPP059
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24.
Automatic Post-Operational Checks for the LHC Beam Dump System / Gallet, E (CERN) ; Axensalva, J (CERN) ; Baggiolini, V (CERN) ; Carlier, E (CERN) ; Goddard, B (CERN) ; Kain, V (CERN) ; Lamont, M (CERN) ; Magnin, N (CERN) ; Verhagen, H (CERN) ; Uythoven, J (CERN)
In order to ensure the required level of reliability of the LHC beam dump system a series of post-operational checks must be performed after each dump action. This paper describes the various data handling and data analysis systems which are required internally and at different levels of the LHC control system, for postoperational checks, and the experience from the commissioning of the equipment where these systems were used to analyse the dump kicker performance..
LHC-PROJECT-Report-1118; CERN-LHC-PROJECT-Report-1118.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP059
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25.
Beam Commissioning of the SPS-to-LHC Transfer Line TI 2 / Uythoven, J (CERN) ; Arduini, Gianluigi (CERN) ; Assmann, Ralph Wolfgang (CERN) ; Gilbert, N (CERN) ; Goddard, B (CERN) ; Kain, V (CERN) ; Koschik, A (CERN) ; Kramer, T (CERN) ; Lamont, M (CERN) ; Mertens, V (CERN) et al.
The transfer line for the LHC Ring 1 was successfully commissioned with beam in the autumn of 2007. After extraction from the SPS accelerator and about 2.7 km of new transfer line, the beam arrived at the temporarily installed beam dump, about 50 m before the start of the LHC tunnel, without the need of any beam threading. [...]
LHC-PROJECT-Report-1119; CERN-LHC-PROJECT-Report-1119.- Geneva : CERN, 2008 - 4 p. Fulltext: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP065
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26.
Results from the LHC Beam Dump Reliability Run / Uythoven, J (CERN) ; Antoine, A (CERN) ; Carlier, E (CERN) ; Castronuovo, F (CERN) ; Ducimetière, L (CERN) ; Gallet, E (CERN) ; Goddard, B (CERN) ; Magnin, N (CERN) ; Verhagen, H (CERN)
The LHC Beam Dumping System is one of the vital elements of the LHC Machine Protection System and has to operate reliably every time a beam dump request is made. Detailed dependability calculations have been made, resulting in expected rates for the different system failure modes. [...]
LHC-PROJECT-Report-1120; CERN-LHC-PROJECT-Report-1120.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP066
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27.
Tracking Tools to Estimate the Quench Time Constants for Magnet Failures in LHC / Gomez Alonso, A (CERN)
At LHC, beam losses, with about 360 MJ of stored energy per beam at nominal collision operation, are potentially dangerous for the accelerator equipment and can also affect the operational efficiency by inducing quenches in superconducting magnets. Magnet failures may affect the beam leading to proton losses primarily in collimators and secondarily in superconducting magnets due to scattering of protons from collimator jaws. [...]
LHC-PROJECT-Report-1121; CERN-LHC-PROJECT-Report-1121.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP069
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28.
Dependence of the Static and Dynamic Field Quality of the LHC Superconducting Dipole Magnets on the Pre-Cycle Ramp Rate / Sammut, N J (Malta U. ; CERN) ; Bottura, L (CERN) ; Deferne, G (CERN) ; Venturini-Delsolaro, W (CERN) ; Wolf, R (CERN)
The allowed multipoles in the Large Hadron Collider (LHC) superconducting dipole magnets decay whilst on a constant current plateau. It is known that the decay amplitude is largely affected by the powering history of the magnet, and particularly by the pre-cycle flat top current and duration and the pre-injection preparation duration. [...]
LHC-PROJECT-Report-1126; CERN-LHC-PROJECT-Report-1126.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPD031
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29.
A Demonstration Experiment for the Forecast of Magnetic Field and Field Errors in the Large Hadron Collider / Sammut, N J (Malta U. ; CERN) ; Alemany-Fernandez, R (CERN) ; Bottura, L (CERN) ; Deferne, G (CERN) ; Lamont, M (CERN) ; Miles, J (CERN) ; Sanfilippo, S (PSI, Villigen) ; Strzelczyk, M (CERN) ; Venturini-Delsolaro, W (CERN) ; Xydi, P (CERN)
In order to reduce the burden on the beam-based feedback, the Large Hadron Collider control system is equipped with the Field Description for the LHC (FiDeL) which provides a forecast of the magnetic field and the multipole field errors. FiDeL has recently been extensively tested at CERN to determine main field tracking, multipole forecasting and compensation accuracy. [...]
LHC-PROJECT-Report-1128; CERN-LHC-PROJECT-Report-1128.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPD033
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30.
Status of the Large Hadron Collider (LHC) / Bordry, Frederick (CERN)
The installation of the LHC (Large Hadron Collider) at CERN is now completed. All magnets are interconnected. [...]
LHC-PROJECT-Report-1130; CERN-LHC-PROJECT-Report-1130.- Geneva : CERN, 2008 - 6 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.MOXAGM01
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31.
Four Quadrant 60 A, 8 V Power Converters for LHC / Montabonnet, V (CERN) ; Ceccone, L (CERN)
The LHC (Large Hadron Collider) particle accelerator requires many true bipolar power converters (752), located under the accelerator dipole magnets in a radioactive environment. A special design and topology are required to obtain the necessary performance while meeting the criteria of radiation tolerance and compact size. [...]
LHC-PROJECT-Report-1132; CERN-LHC-PROJECT-Report-1132.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.THPP126
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32.
Review of the Initial Phases of the LHC Power Converter Commissioning / Nisbet, D (CERN) ; Thiesen, H (CERN)
The LHC requires more than 1700 power converter systems that supply between 60A and 13kA of precisely regulated current to the superconducting magnets. For the first time at CERN these converters have been installed underground in close proximity to many other accelerator systems. [...]
LHC-PROJECT-Report-1133; CERN-LHC-PROJECT-Report-1133.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.THPP132
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33.
Overall Optics Solutions for very high Beta in ATLAS / White, S (CERN) ; Burkhardt, W (CERN) ; Cavalier, S (Orsay, LAL) ; Heller, M (Orsay, LAL) ; Puzo, P (CERN)
An insertion optics with a $\beta$* of at least 2600m has been requested by the ATLAS experiment at the LHC. This is very far from the standard LHC physics optics and implies a significant reduction in the phase advance from this insertion corresponding to about half a unit in tune. [...]
LHC-PROJECT-Report-1135; CERN-LHC-PROJECT-Report-1135.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP004
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34.
Crab Compensation for LHC Beams / Calaga, R (Brookhaven) ; Sun, Y (CERN) ; Tomás, R (CERN) ; Zimmermann, F (CERN)
An R&D; program to establish a road map for the installation of crab cavities in the LHC is rapidly advancing. Both local and global crab schemes are under investigation to develop cavities that will be compatible with the LHC optics and meet the aperture requirements. [...]
LHC-PROJECT-Report-1136; CERN-LHC-PROJECT-Report-1136.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP007
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35.
Linac-LHC EP Collider Options / Zimmermann, F (CERN) ; Aksahal, H (Nigde U.) ; Bordry, Frederick (CERN) ; Braun, H H (CERN) ; Brüning, Oliver Sim (CERN) ; Çiftçi, A K (Ankara U.) ; Chattopadhyay, S (Cockcroft Inst. Accel. Sci. Tech.) ; Dainton, J B (Liverpool U.) ; de Roeck, A (CERN) ; Eide, A (EPFL-LPHE, Lausanne) et al.
We describe various parameter scenarios for a ring-linac ep collider based on LHC and an independent electron linac. Luminosities between $10^{31}$ and $10^{33} cm^{-2}s^{-1}$ can be achieved with a s.c. [...]
LHC-PROJECT-Report-1137; CERN-LHC-PROJECT-Report-1137; CERN-LHeC-Note-2008-002 ACC.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP154
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36.
Commissioning of the 400 MHz LHC RF System / Ciapala, Edmond (CERN) ; Arnaudon, L (CERN) ; Baudrenghien, P (CERN) ; Brunner, O (CERN) ; Butterworth, A (CERN) ; Linnecar, T (CERN) ; Maesen, P (CERN) ; Molendijk, J (CERN) ; Montesinos, E (CERN) ; Valuch, D (CERN) et al.
The installation of the 400 MHz superconducting RF system in LHC is finished and commissioning is under way. The final RF system comprises four cryo-modules each with four cavities in the LHC tunnel straight section round IP4. [...]
LHC-PROJECT-Report-1147; CERN-LHC-PROJECT-Report-1147.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.MOPP124
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37.
LHC Transverse Feedback System and its Hardware Commissioning / Baudrenghien, P (CERN) ; Gorbachev, E V (Dubna, JINR) ; Höfle, Wolfgang (CERN) ; Killing, F (CERN) ; Kojevnikov, I (CERN) ; Kotzian, G (CERN) ; Lebedev, N I (Dubna, JINR) ; Louwerse, R (CERN) ; Makarov, A A (Dubna, JINR) ; Montesinos, E (CERN) et al.
A powerful transverse feedback system ("Damper") has been installed in LHC. It will stabilise coupled bunch instabilities in a frequency range from 3 kHz to 20 MHz and at the same time damp injection oscillations originating from steering errors and injection kicker ripple. [...]
LHC-PROJECT-Report-1148; CERN-LHC-PROJECT-Report-1148.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.THPC121
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38.
Digital Signal Processing for the Multi-Bunch LHC Transverse Feedback System / Baudrenghien, P (CERN) ; Höfle, Wolfgang (CERN) ; Kotzian, G (CERN) ; Rossi, V (CERN)
For the LHC a VME card has been developed that contains all functionalities for transverse damping, diagnostics and controlled bunch by bunch excitation. It receives the normalized bunch by bunch position from two pick-ups via Gigabit Serial Links (SERDES). [...]
LHC-PROJECT-Report-1151; CERN-LHC-PROJECT-Report-1151.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.THPC122
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39.
A Beam Quality Monitor for LHC Beams in the SPS / Papotti, G (CERN)
The SPS Beam Quality Monitor (BQM) system monitors the longitudinal parameters of the beam before extraction to the LHC to prevent losses and degradation of the LHC luminosity by the injection of low quality beams. It is implemented in two priority levels. [...]
LHC-PROJECT-Report-1154; CERN-LHC-PROJECT-Report-1154.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.THPC144
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40.
LHC Transverse Feedback Damping Efficiency / Kotzian, G (CERN) ; Höfle, Wolfgang (CERN) ; Vogel, E (DESY)
A simulation model has been developed to predict the damping efficiency of the LHC transverse feedback system in the presence of coupled bunch instabilities and under realistic assumptions for the injection error. The model tracks both the centre of gravity of a bunch and the r.m.s beam size during and after injection. [...]
LHC-PROJECT-Report-1156; CERN-LHC-PROJECT-Report-1156.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.THPP114
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41.
Generation of 1.5 Million Beam Loss Threshold Values / Holzer, E B (CERN) ; Bocian, D (CERN) ; Böhlen, T T (CERN) ; Dehning, B (CERN) ; Kramer, Daniel (CERN) ; Ponce, L (CERN) ; Priebe, A (CERN) ; Sapinski, M (CERN) ; Stockner, M (CERN)
CERN's Large Hadron Collider will store an unprecedented amount of energy in its circulating beams. Beamloss monitoring (BLM) is, therefore, critical for machine protection. [...]
LHC-PROJECT-Report-1158; CERN-LHC-PROJECT-Report-1158.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.THPC147
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42.
Results of the LHC Prototype Chromaticity Measurement System Studies in the CERN-SPS / Steinhagen, R (CERN) ; Boccardi, A (CERN) ; Bohl, T (CERN) ; Gasior, M (CERN) ; Jones, O R (CERN) ; Kasinski, K K (AGH-UST, Cracow) ; Wenninger, J (CERN)
Tune and chromaticity control is an integral part of safe and reliable LHC operation. Tight tolerances on the maximum beam excursions allow excitation amplitudes of less than 30 $\mu$m. [...]
LHC-PROJECT-Report-1159; CERN-LHC-PROJECT-Report-1159.- Geneva : CERN, 2008 - 4 p. Fulltext: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.TUPC098
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43.
Abort Gap Cleaning using the Transverse Feedback System : Simulation and Measurements in the SPS for the LHC Beam Dump System / Koschik, A (CERN) ; Goddard, B (CERN) ; Höfle, Wolfgang (CERN) ; Kotzian, G (CERN) ; Kramer, Daniel (CERN) ; Kramer, T (CERN)
The critical and delicate process of dumping the beams of the LHC requires very low particle densities within the $3 \mu$s of the dump kicker rising edge. High beam population in this so-called 'abort gap' might cause magnet quenches or even damage. [...]
LHC-PROJECT-Report-1160; CERN-LHC-PROJECT-Report-1160.- Geneva : CERN, 2008 - 4 p. Fulltext: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP060
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44.
Apertures in the LHC Beam Dump System and Beam Losses During Beam Abort / Kramer, T (CERN) ; Goddard, B (CERN) ; Gyr, M (CERN) ; Koschik, A (CERN) ; Uythoven, J (CERN) ; Weiler, T (CERN)
The LHC beam dumping system (LBDS) is used to dispose accelerated protons and ions in a wide energy range from 450 GeV up to 7 TeV. An abort gap of $3 \mu$s is foreseen to avoid sweeping particles through the LHC ring aperture. [...]
LHC-PROJECT-Report-1161; CERN-LHC-PROJECT-Report-1161.- Geneva : CERN, 2008 - 4 p. Fulltext: LHC-PROJECT-REPORT-1161_2 - PDF; LHC-PROJECT-REPORT-1161 - PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP064
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45.
Impact Distribution of the Beam Losses at the LHC Collimators in Case of Magnet Failures / Gómez Alonso, A (CERN)
During LHC operation, magnet failures may affect the beam optics leading to proton losses in the collimators. These losses, with about 360MJ of stored energy per beam at nominal collision operation, are potentially dangerous for the accelerator equipment. [...]
LHC-PROJECT-Report-1162; CERN-LHC-PROJECT-Report-1162.- Geneva : CERN, 2008 - 4 p. Preprint: PDF; External link: Published version from JACoW
In : 11th European Particle Accelerator Conference, Genoa, Italy, 23 - 27 Jun 2008, pp.WEPP068
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46.

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