EPAC 2006 - List of Keywords

A B C D E F G H I K L M O P Q R S T U V W X

LHC

Paper	Title	Other Keywords	Page
MOYBPA01	LHC Progress and Commissioning Plans	injection, dipole, quadrupole, luminosity	14
	O.S. Brüning CERN, Geneva
	The LHC at CERN is in its final installation phase, and the first tests with beam are planned for part of the machine for the end of 2006. The commissioning of the full machine with beam is planned for summer 2007. The talk summarizes the current status of the LHC installation and the strategy for obtaining an optimum hardware configuration. In a second part the talk outlines the main milestones for the hardware and beam commissioning and presents estimates for the expected performance levels for the commissioning phase with beam.
	Transparencies

MOPCH091	An Alternative Nonlinear Collimation System for the LHC	collimation, sextupole, optics, insertion	246
	J. Resta-López, R.W. Assmann, S. Redaelli, J. Resta-López, G. Robert-Demolaize, D. Schulte, F. Zimmermann CERN, Geneva A. Faus-Golfe IFIC, Valencia
	The optics design of an alternative nonlinear collimation system for the LHC is presented. We discuss an optics scheme based on a single spoiler located in between a pair of skew sextupoles for betatron collimation. The nonlinear system allows opening up the collimator gaps and, thereby reduces the collimator impedance, which presently limits the LHC beam intensity. After placing secondary absorbers at optimum locations behind the spoiler, we analyze the beam losses and calculate the cleaning efficiency from tracking studies. The results are compared with those of the conventional linear collimation system.

MOPCH094	Low-intensity Beams for LHC Commissioning from the CERN PS-booster	emittance, injection, CERN, proton	255
	M. Benedikt, J. Tan CERN, Geneva
	A variety of low-intensity beams will be required for LHC commissioning. In contrast to the nominal LHC physics beam, these single-bunch beams are produced without longitudinal bunch splitting in the injector chain. Consequently, not only the transverse but also the longitudinal beam characteristics have already to be established in the CERN PS-Booster. The required intensities extend down to four orders of magnitude below the typical PS-Booster working range and the transverse emittances must be adjustable to vary the beam brightness over a large range. The different beam variants are briefly summarized and the specific techniques developed for their production, like low-voltage rf capture, and transverse and longitudinal shaving, are described. In particular, the choice of harmonic number and its consequences for operation and beam reproducibility are discussed. Finally, the performance achieved for the different beams is summarized.

MOPCH095	Performance of Nominal and Ultimate LHC Beams in the CERN PS-booster	injection, emittance, optics, CERN	258
	M. Benedikt, M. Chanel, K. Hanke CERN, Geneva
	The requirements for nominal and ultimate LHC beams in the CERN PS-Booster were specified in 1993 and served as input for the definition of the "PS conversion for LHC" project. Already during the upgrade project and also after its completion in 2000, the beam intensities to be provided from the PS Booster were increased in order to compensate for changes on the LHC machine, the beam production scheme in the PS and for non-anticipated beam losses along the injector chain. In order to improve the beam brightness, to be compatible with the increased requirements, extensive machine studies have taken place on the PS-Booster. The working point was changed to reduce the influence of systematic resonances and the injection line optics was re-matched to improve the injection efficiency. The paper summarizes briefly the evolution of the performance requirements. The various measures undertaken to improve the LHC beam quality are outlined and the present performance achieved in the PS-Booster is presented.

MOPCH098	LHC@FNAL: A Remote Access Center for the LHC at Fermilab	CERN, monitoring, controls, luminosity	267
	E.S. McCrory, K.B. Biery, E.G. Gottschalk, S.G. Gysin, E.R. Harms, S.K. Kunori, M.J. Lamm, K.M. Maeshima, P.M. McBride, A.J. Slaughter, A.D. Thomas Fermilab, Batavia, Illinois M. Lamont CERN, Geneva
	A facility is being designed at Fermilab to help people contribute to the Large Hadron Collider (LHC) effort at CERN. This facility is called LHC@FNAL. The purpose of LHC@FNAL is to permit members of the LHC community in North America contribute their expertise to LHC activities at CERN, and to assist CERN with the commissioning and operation of the LHC accelerator and CMS experiment. As a facility, LHC@FNAL has three primary functions: 1) To provide access to information in a manner that is similar to what is available in control rooms at CERN, and to enable members of the LHC community to participate remotely in LHC and CMS activities. 2) To serve as a (bidirectional) communications conduit between CERN and members of the LHC community located in North America. 3. To allow visitors to Fermilab to see firsthand how research is progressing at the LHC. Visitors will be able to see current LHC activities, and will be able to see how future international projects in particle physics can benefit from active participation in projects at remote locations. LHC@FNAL is expected to contribute to a wide range of activities for the CMS experiment and for the LHC accelerator.

MOPCH124	Energy Deposition in Adjacent LHC Superconducting Magnets from Beam Loss at LHC Transfer Line Collimators	simulation, beam-losses, proton, collimation	336
	V. Kain, S. Beavan, Y. Kadi CERN, Geneva
	Injection intensities for the LHC are over an order of magnitude above the damage threshold. The collimation system in the two transfer lines is designed to dilute the beam sufficiently to avoid damage in case of accidental beam loss or mis-steered beam. To maximise the protection for the LHC most of the collimators are located in the last 300 m upstream of the injection point where the transfer lines approach the LHC machine. To study the issue of possible quenches following beam loss at the collimators the entire collimation section in one of the lines, TI 8, together with the adjacent part of the LHC has been modeled in FLUKA. The simulated energy deposition in the LHC for worst-case accidental losses as well as for losses expected during a normal filling is presented. The operational implications are discussed.

MOPCH133	An Analytic Calculation of the Electron Cloud Linear Map Coefficient	electron, simulation, RHIC, heavy-ion	357
	U. Iriso CELLS, Bellaterra (Cerdanyola del Vallès) S. Peggs BNL, Upton, Long Island, New York
	The evolution of the electron density during multibunch electron cloud formation can often be reproduced using a bunch-to-bunch iterative map formalism. The coefficients that parameterize the map function are readily obtained by fitting to results from compute-intensive electron cloud simulations. This paper derives an analytic expression for the linear map coefficient that governs weak cloud behaviour from first principles. Good agreement is found when analytical results are compared with linear coefficient values obtained from numerical simulations. This analysis is useful in predicting thresholds beyond which electron cloud formation occurs, and thus in determining safety regions in parameter space where an accelerator can be operated without creating electron clouds. The formalism explicitly shows that the multipacting resonance condition is not a sine qua non for electron cloud formation.

MOPCH144	Low Temperature Properties of Piezoelectric Actuators Used in SRF Cavities Cold Tuning Systems	radiation, TESLA, target, cyclotron	390
	G. Martinet, S. Blivet, F. Chatelet, M. Fouaidy, N. Hammoudi, A. Olivier, H. Saugnac IPN, Orsay
	High accelerating gradients (10 MV/m for SNS, 33 MV/m for ILC) at which SRF cavities will be operated in pulsed machines induce frequency shift much higher than the resonator bandwidth. This so-called Lorentz detuning should be compensated dynamically by means of an active piezo-tuning system. In the frame of the CARE project activities supported by EU, IPN Orsay participates to the development of a fast cold tuning system based and piezoelectric technology for SRF cavities operating at temperature T=2K. The aim of this study is the full characterization of piezoelectric actuators at low temperature including dielectric properties (capacitance, impedance, dielectric losses), radiation hardness tests (fast neutron tolerance), mechanical measurements (maximum displacement, maximum stroke) and thermal properties (heating, heat capacity). Results obtained in the temperature range from 2K up to 300K will be presented and discussed.

MOPCH191	Copper Heat Exchanger for the External Auxiliary Bus-bars Routing Line in the LHC Insertion Regions	CERN, cryogenics, quadrupole, insertion	508
	C. Garion, A. Poncet, F. Seyvet, J.-P.G. Tock CERN, Geneva M. Sitko, B. Skoczen CUT, Krakow
	The corrector magnets and the main quadrupoles of the LHC dispersion suppressors are powered by a special superconducting line (called auxiliary bus-bars line N), external to the cold mass and housed in a 50 mm diameter stainless steel tube fixed to the cold mass. As the line is periodically connected to the cold mass, the same gaseous and liquid helium is used for cooling the magnets and the line. The final sub-cooling process (from 4.5 K down to 1.9 K) consists of the phase transformation from liquid to superfluid helium. It is slightly delayed with respect to the magnets. To accelerate the process, a special heat exchanger has been designed. Located in the middle of the dispersion suppressor portion of the line it consists in creating a local sink of heat extraction, providing two additional λ fronts that propagate in opposite directions towards the line extremities. Both the numerical model and the sub-cooling analysis are presented in the paper for different configurations of the line. Design, manufacturing and integration aspects of the heat exchanger are described. Finally, the results of the qualification tests and the expected performance of the line are given.

MOPLS001	Large Scale Beam-beam Simulations for the CERN LHC using Distributed Computing	CERN, dynamic-aperture, simulation, beam-beam-effects	526
	W. Herr, E. McIntosh, F. Schmidt CERN, Geneva D. Kaltchev TRIUMF, Vancouver
	We report on a large scale simulation of beam-beam effects for the CERN Large Hadron Collider (LHC). The stability of particles which experience head-on and long-range beam-beam effects was investigated for different optical configurations and machine imperfections. To cover the interesting parameter space required computing resources not available at CERN. The necessary resources were available in the LHC@home project, based on the BOINC platform. At present, this project makes more than 40000 hosts available for distributed computing. We shall discuss our experience using this system during a simulation campaign of more than six months and describe the tools and procedures necessary to ensure consistent results. The results from this extended study are presented and future plans are discussed.

MOPLS002	The Study of the Machine-induced Background and its Applications at the LHC	background, insertion, shielding, CERN	529
	V. Talanov, I. Azhgirey, I. Baishev IHEP Protvino, Protvino, Moscow Region D. Macina, K.M. Potter, E. Tsesmelis CERN, Geneva
	We present the recent advances in the analysis of the machine-induced background generation and formation at the LHC. Different aspects of the study of the machine background problem at the LHC are reviewed, including the background production at the different stages of the machine operation, the role and influence on the background from the collimators in the experimental insertions and the background shielding. The potential use of the machine background for the purposes of detector testing and alignment is also discussed.

MOPLS003	Tertiary Halo and Tertiary Background in the Low Luminosity Experimental Insertion IR8 of the LHC	background, shielding, insertion, simulation	532
	V. Talanov IHEP Protvino, Protvino, Moscow Region R.W. Assmann, D. Macina, K.M. Potter, S. Redaelli, G. Robert-Demolaize, E. Tsesmelis CERN, Geneva
	In our report we present the results for numerical simulation of tertiary halo and tertiary background in the LHC. We study the case of the proton losses in the betatron cleaning insertion IR7 with the subsequent tertiary halo generation in the downstream experimental insertion IR8. We analyze the formation of tertiary background in the experimental area of the IR8 and evaluate the performance of the machine-detector interface shielding with respect to this source of the background. The results obtained are compared with the previous estimates of the machine-induced background in the low luminosity insertions of the LHC, and the balance between different sources of the background is discussed.

MOPLS004	Estimation and Analysis of the Machine-induced Background at the TOTEM Roman Pot Detectors in the IR5 of the LHC	background, optics, simulation, hadron	535
	V. Talanov IHEP Protvino, Protvino, Moscow Region V. Avati Helsinki University, Department of Physics, University of Helsinki M. Deile, D. Macina CERN, Geneva
	The problem of background generation in the experimental insertion IR5 of the LHC during machine operation in the dedicated TOTEM mode with low intensity beams and the specially designed beta* = 1540 m optics is discussed. The sources of the machine-induced background in the IR5 forward physics areas are identified and their relative importance is evaluated. The results of the background simulation in the IR5 are presented, based on the most recent estimates of the residual gas density for TOTEM beam conditions. The methods for background analysis and rejection are explained.

MOPLS005	A Staged Approach to LHC Commissioning	instrumentation, controls, CERN, vacuum	538
	R. Bailey, O.S. Brüning, P. Collier, M. Lamont, R.J. Lauckner, R. Schmidt CERN, Geneva
	After a brief reminder of the performance goals of the LHC, the overall strategy proposed for commissioning the machine with protons is presented. A thorough commissioning of the LHC hardware systems, presently ongoing, will lead into a staged approach for the first two years of operation with the beam, allowing both the complexity of the machine operation and the destructive power of the high intensity beams to be introduced in a controlled, incremental manner. The demands on the annual machine schedule are discussed, including the need to incorporate dedicated running for ions and proton-proton total cross section measurements. An important pre-commissioning milestone is the injection of the beam into a sector of the partially completed LHC; the motivation and tests planned are briefly summarised.

MOPLS006	Adaptive RF Transient Reduction for High Intensity Beams with Gaps	feedback, simulation, beam-losses, synchrotron	541
	J. Tuckmantel, P. Baudrenghien CERN, Geneva
	When a high-intensity beam with bunch-trains and gaps passes a cavity with a high-gain vector feedback enforcing a constant voltage, large transients appear, stressing the RF high power hardware and increasing the trip rate. By modulating the cavity voltage with a varying periodic waveform (set-function), the RF power can be made constant while still preserving the high feedback gain. The average cavity voltage is conserved but bunches have to settle at slightly shifted positions. A method is derived to obtain this set-function in practice while making no assumptions or measurements of the beam or RF parameters. Adiabatic iterations are made, including the whole machine as an analog computing device, using all parameters as they are. A computer simulation shows the success of the method.

MOPLS007	Monitoring Heavy-ion Beam Losses in the LHC	ion, proton, simulation, collimation	544
	R. Bruce, G. Bellodi, H.-H. Braun, S.S. Gilardoni, J.M. Jowett CERN, Geneva
	The LHC beam loss monitor (BLM) system, primarily designed for proton operation, will survey particle losses and dump the beam if the loss rate exceeds a threshold expected to induce magnet quenches. Simulations of beam losses in the full magnet geometry allow us to compare the response of the BLMs to ion and proton losses and establish preliminary loss thresholds for quenches. Further simulations of beam losses caused by collimation and electromagnetic interactions peculiar to heavy ion collisions determine the positions of extra BLMs needed for ion operation in the LHC.

MOPLS008	Beam Halo on the LHC TCDQ Diluter System and Thermal Load on the Downstream Superconducting Magnets	collimation, simulation, insertion, superconducting-magnet	547
	B. Goddard, R.W. Assmann, A. Presland, S. Redaelli, G. Robert-Demolaize, L. Sarchiapone, Th. Weiler, W.J.M. Weterings CERN, Geneva
	The moveable single-jawed graphite TCDQ diluter must be positioned very close to the circulating LHC beam in order to prevent damage to downstream components in the event of an unsynchronised beam abort. A two-jawed graphite TCS collimator forms part of the TCDQ system. The requirement to place the TCDQ and TCS jaws close to the beam means that the system can intercept a substantial beam halo load. Initial investigations indicated a worryingly high heat load on the Q4 coils. This paper presents the updated load cases, shielding and simulation geometry, and the results of simulations of the energy deposition in the TCDQ system and in the downstream superconducting Q4 magnet. The implications for the operation of the LHC are discussed.

MOPLS009	The LHC as a Proton-nucleus Collider	ion, proton, injection, SPS	550
	J.M. Jowett, C. Carli CERN, Geneva
	Following its initial operation as a proton-proton (p-p) and heavy-ion (208Pb⁸²⁺ - 208Pb⁸²⁺) collider, the LHC is expected to operate as a p-Pb collider. Later it may collide protons with other lighter nuclei such as 40Ar¹⁸⁺ or 16O⁸⁺. We show how the existing proton and lead-ion injector chains may be efficiently operated in tandem to provide these hybrid collisions. The two-in-one magnet design of the LHC main rings imposes different revolution frequencies for the two beams in part of the magnetic cycle. We discuss and evaluate the consequences for beam dynamics and estimate the potential performance of the LHC as a proton-nucleus collider.

MOPLS010	Measurement of Ion Beam Losses Due to Bound-free Pair Production in RHIC	ion, RHIC, luminosity, simulation	553
	J.M. Jowett, S.S. Gilardoni CERN, Geneva R. Bruce MAX-lab, Lund K.A. Drees, W. Fischer, S. Tepikian BNL, Upton, Long Island, New York S.R. Klein LBNL, Berkeley, California
	When the LHC operates as a Pb⁸²⁺ ion collider, losses of Pb⁸¹⁺ ions, created through Bound-free Pair Production (BFPP) at the collision point, and localized in cold magnets, are expected to be a major luminosity limit. With Au⁷⁹⁺ ions at RHIC, this effect is not a limitation because the Au⁷⁸⁺ production rate is low, and the Au⁷⁸⁺ beam produced is inside the momentum aperture. When RHIC collided Cu²⁹⁺ ions, secondary beam production rates were lower still but the Cu²⁸⁺ ions produced were predicted to be lost at a well-defined location, creating the opportunity for the first direct observation of BFPP effects in an ion collider. We report on measurements of localized beam losses due to BFPP with copper beams in RHIC and comparisons to predictions from tracking and Monte Carlo simulation.

MOPLS011	Investigations of the Parameter Space for the LHC Luminosity Upgrade	luminosity, quadrupole, insertion, separation-scheme	556
	J.-P. Koutchouk CERN, Geneva
	Increasing the LHC luminosity by a factor of ten is a major challenge, not so much for the beam optics but certainly for the beam-beam long-range interactions and even more for the technology and layout: the quadrupole gradient, its physical aperture and tolerance to the energy deposition shall be significantly increased; its distance to the crossing point shall be reduced if the particle detectors can allow it. To help identifying consistent solutions in this multi-dimensional constrained space, a algorithmic model of an LHC insertion was prepared, based on the present LHC layout, i.e., "quadrupole first" and small crossing angle. The model deals with the layout, the beam optics, the beam-beam effect, the superconductor field margins and the peak heat deposition in the coils. The approach is simplified to allow a large gain in the design/computation time for optimization. First results have shown the need to use the Nb3Sn technology (or a material of equivalent performance) to reach the performance goal. In this paper, the model is refined to take into account the quench levels and temperature margins. The optimal insertions within the framework of this approach are identified.

MOPLS012	The LHC Sector Test	controls, injection, instrumentation, radiation	559
	M. Lamont, R. Bailey, H. Burkhardt, B. Goddard, L.K. Jensen, O.R. Jones, V. Kain, A. Koschik, R.I. Saban, J.A. Uythoven, J. Wenninger CERN, Geneva
	The proposal to inject beam into a sector of the partially completed LHC is presented. The test will provide an important milestone, force preparation of a number of key systems, and allow a number of critical measurements with beam. The motivation for the test is discussed, along with the proposed beam studies, the radiation issues and the potential impact on ongoing installation. The demands on the various accelerator systems implicated are presented along with the scheduling of the preparatory steps, the test itself and the recovery phase.

MOPLS013	The Roman Pot for LHC	vacuum, optics, radiation, scattering	562
	M. Oriunno, M. Deile, K. Eggert, J.-M. Lacroix, S.J. Mathot, E.P. Noschis, R. Perret, E.R. Radermacher, G. Ruggiero CERN, Geneva
	The LHC machine will be equipped with Roman Pot stations by the TOTEM experiment to measure the pp total cross section and to study the elastic scattering and the diffraction physics processes. TOTEM needs to bring the pots, equipped with cold micro-strip silicon detectors, as a close as possible to the high intensity beam of LHC. Because of the special optics required by TOTEM, the beam has a transversal size of only 80 microns at the Roman pot locations. Safety considerations for the machine protection set the limit to 10 ?, i.e. 800 μm. Such unprecedented parameters, together with the issues of the Ultra High Vacuum and the RF compatibility, and the harsh radiation environment, have requested a design for the Roman Pot system, which is compliant with the LHC requirements and operations. To better meet also the challenging requirements of TOTEM, a technology development of a thin window has been pursued and a flatness of less than 50 μm has been obtained by brazing foil of 150 μm thicknesses. A prototype of the Roman Pot and of the thin window box have been manufactured and tested. We describe the main issues of the final design and the results of the preliminary tests.

MOPLS014	Lifetime Limit from Nuclear Intra-bunch Scattering for High-energy Hadron Beams	scattering, proton, ion, injection	565
	F. Zimmermann, H.-H. Braun, F. Ruggiero CERN, Geneva
	We derive an approximate expression for the nuclear scattering rate inside a bunched hadron beam. Application to the LHC suggests that the loss rate due to nuclear scattering can be significant in high-energy proton or ion storage rings.

MOPLS015	Quality Control Techniques Applied to the Large Scale Production of Superconducting Dipole Magnets for LHC	CERN, dipole, controls, target	568
	F. Savary, M. Bajko, J. Beauquis, G. De Rijk, N. Emelianenko, P. Fessia, P. Hagen, J. Miles, L. Rossi, E. Todesco, J. Vlogaert, C. Vollinger, E.Y. Wildner CERN, Geneva
	The LHC accelerator, under construction at CERN, is characterized by the use on a large scale of high field superconducting dipoles: the 27-km ring requires 1232 15-m long dipole magnets designed for a peak field of 9 T. The coils are wound with Rutherford-type cable based on copper-stabilized Nb-Ti superconductors and will be operated at 1.9 K in pressurized superfluid helium. The challenge that had to be faced has been an efficient, cost-effective and reproducible mass production to very tight tolerances: the field quality must be better than 10^-4 and the geometry of the cold bore tube and magnet controlled to 0.1 mm over the whole length, any deviation being liable to induce delays and significant cost increase. This paper presents the main methods and tools chosen to face successfully this challenge: some methods were foreseen in the technical specification, others were implemented based on the experience gained in several years of fabrication.

MOPLS016	LHC IR Upgrade: A Dipole First Option with Local Chromaticity Correction	sextupole, dipole, luminosity, dynamic-aperture	571
	R. de Maria, O.S. Brüning CERN, Geneva P. Raimondi INFN/LNF, Frascati (Roma)
	In the framework of the LHC Luminosity Upgrade, we develop a new layout of the interaction region (IR) with betastar equal to 25cm in which the combination-separation dipoles come first with respect to the triplet assembly (dipole first) in opposition of the nominal layout (quadrupole first). The new layout presents several advantages (separate channel for multipole errors, straightforward crossing angle scheme, early separation of the beam). The payoff is a large beta function in the triplet, which enhances the chromaticity and other non-linear effects. We investigate options for local chromaticity correction and their effects on long-term stability.

MOPLS017	A Low Gradient Triplet Quadrupole Layout Compatible with NbTi Magnet Technology and Betastar=0.25m	sextupole, luminosity, quadrupole, CERN	574
	R. de Maria, O.S. Brüning CERN, Geneva
	The paper presents a triplet layout option with long (ca. 100 m total triplet length), low gradient (45 T/m to 70 T/m) quadrupole magnets. Assuming a maximum magnet diameter of 200mm, the peak coil field at the magnet coils still remains below 7 T which is still compatible with conventional NbTi magnet technology. The peak beta function inside the triplet magnets reaches 18 km and the configuration therefore requires an additional chromaticity correction scheme similar to a dipole first layout option. However, at the same time, the presented solution provides an interesting alternative to a high gradient triplet layout which requires the new Nb3Ti magnet technology.

MOPLS020	Rad-hard Luminosity Monitoring for the LHC	luminosity, radiation, CERN, controls	580
	A. Ratti, J.-F. Beche, J.M. Byrd, K. Chow, S. De Santis, P. Denes, B. Ghiorso, H.S. Matis, M. T. Monroy, W.C. Turner LBNL, Berkeley, California E. Bravin CERN, Geneva P.F. Manfredi Pavia University, Engineering faculty, Pavia W. Vandelli Pavia University, Pavia
	Luminosity measurements at the high luminosity points of the LHC are very challenging due to the extremely high radiation levels in excess of 1 GGy/yr. We have designed an ionization chamber that uses a flowing gas mixture and a combination of metals and ceramics. With such a choice, an additonal challenge is achieving the necessary speed to be able to resolve bunch-by-bunch luminosity data. We present the design, analysis and experimental results of the early demonstration tests of this device.

MOPLS055	A Lepton-proton Collider with LHC	proton, lepton, luminosity, collider	670
	F.J. Willeke DESY, Hamburg J.B. Dainton Cockcroft Institute, Warrington, Cheshire M. Klein DESY Zeuthen, Zeuthen P. Newman Birmingham University, Birmingham E. Perez CEA, Gif-sur-Yvette
	The physics, and a design, of a Large Hadron Electron Collider (LHeC) are sketched. With high luminosity, 10³³cm-2s-1, and high energy, ?s = 1.4TeV, such a collider can be built in which a 70GeV electron (positron) beam in the LHC tunnel is in collision with one of the LHC hadron beams and which operates simultaneously with the LHC. The LHeC makes possible deep-inelastic lepton-hadron (ep, eD and eA) scattering for momentum transfers Q2 beyond 106GeV2 and for Bjorken x down to the 10-6. New sensitivity to the existence of new states of matter, primarily in the lepton-quark sector and in dense partonic systems, is achieved. The precision possible with an electron-hadron experiment brings in addition crucial accuracy in the determination of hadron structure, as described in Quantum Chromodynamics, and of parton dynamics at the TeV energy scale. The LHeC thus complements the proton-proton and ion programmes, adds substantial new discovery potential to them, and is important for a full understanding of physics in the LHC energy range. Contributed to the Open Symposium on European Strategy for Particle Physics Research, LAL Orsay, France, January 30th to February 1st , 2006. hep-ex/0603016 DESY 06-00Cockcroft-06-05

MOPLS056	QCD Explorer Proposal: E-linac versus E-ring	collider, electron, CLIC, LEP	673
	H. Karadeniz TAEK, Ankara S. Sultansoy Gazi University, Faculty of Science and Arts, Ankara
	TeV center of mass energy lepton-hadron collider is necessary both to clarify fundamental aspects of strong interactions and for adequate interpretation of the LHC data. Recently proposed QCD Explorer utilizes the energy advantage of the LHC proton and ion beams, which allows the usage of relatively low energy electron beam. Two options for the LHC based ep collider are possible: construction of a new electron ring in the LHC tunnel or construction of an e-linac tangentially to the LHC. In the latter case, which seems more acceptable for a number of reasons, two options are under consideration for electron linac: the CLIC technology allows shorter linac length, whereas TESLA technology gives higher luminosity.

MOPLS064	Measurement of Ground Motion in Various Sites	site, ground-motion, DESY, synchrotron	691
	W. Bialowons, R. Amirikas, A. Bertolini, D. Kruecker DESY, Hamburg
	This presentation will be an overview of a study program, initiated in DESY, to measure ground vibration of various sites which can be used for site characterization for the International Linear Collider (ILC) design. Commercial broadband seismometers have been used to measure ground motion, correlation and surface wave velocity. The database of measured ground vibrations is available to the scientific community. A parameterization of the spectra will also be presented.

TUXPA03	LHC Luminosity and Energy Upgrades	luminosity, dipole, SPS, injection	910
	W. Scandale CERN, Geneva
	LHC upgrade studies are ongoing as part of the EU CARE-HHH network and in the US-LARP collaboration. The aim is a ten-fold increase of the LHC luminosity by about 2014 and a possible upgrade of the injector complex to inject at 1 TeV and, at a later stage, to raise the collider energy. This talk will provide an overview of the beam dynamics and technological challenges associated with the LHC upgrade, including magnet R&D plans, electron cloud and beam-beam limitations, preferred scenarios to maximize the integrated luminosity, and machine experiments on beam-beam compensation or crystal collimation.
	Transparencies

TUODFI01	The Final Collimation System for the LHC	collimation, insertion, impedance, proton	986
	R.W. Assmann, O. Aberle, G. Bellodi, A. Bertarelli, C.B. Bracco, H.-H. Braun, M. Brugger, S. Calatroni, R. Chamizo, A. Dallocchio, B. Dehning, A. Ferrari, P. Gander, A. Grudiev, E.B. Holzer, J.-B. Jeanneret, J.M. Jimenez, M. Jonker, Y. Kadi, K. Kershaw, J. Lendaro, J. Lettry, R. Losito, M. Magistris, A.M. Masi, M. Mayer, E. Métral, R. Perret, C. Rathjen, S. Redaelli, G. Robert-Demolaize, S. Roesler, F. Ruggiero, M. Santana-Leitner, P. Sievers, M. Sobczak, E. Tsoulou, V. Vlachoudis, Th. Weiler CERN, Geneva I. Baishev, I.L. Kurochkin IHEP Protvino, Protvino, Moscow Region
	The LHC collimation system has been re-designed over the last three years in order to address the unprecedented challenges that are faced with the 360 MJ beams at 7 TeV. The layout of the LHC has now been fixed and a final approach for collimation and cleaning has been adopted. In total 132 collimator locations have been reserved in the two LHC rings and can be installed in a phased approach. Ninety collimators of five different types will be available for initial beam operation. The system has been fully optimized for avoiding quenches of super-conducting magnets during beam losses and for sufficient survival of beamline components against radioactive dose. The phased approach for LHC collimation is described, the various collimators and their functionalities are explained, and the expected system performance is summarized.
	Transparencies

TUPCH177	Measurement of the Sorption Characteristics of NEG Coated Pipes: The Transmission Factor Method	vacuum, CERN, ERL, background	1432
	A. Bonucci, A. Conte, P. Manini, S. Raimondi SAES Getters S.p.A., Lainate
	ZrTiV Non Evaporable Getter (NEG) coatings of vacuum chambers have found application in the particle accelerators to lower the gas pressure, during the operative conditions. For that, the characterization of the actual pumping speed of the NEG coating is a key issue. It is carried out by means of the dynamic sorption method according to ASTM F798-82 standard, conducted "offline" on a sample (coupon), suitably positioned inside the chamber to be coated and recovered after the process. To evaluate in-situ the sorption characteristics of getter coated chambers, a different measurement technique (Trasmission Factor Method) is here described. It is based on the measurement of pressures ratio at the inlet and the outlet of a coated pipe, under a flow of test gas. A calibration curve permits to evaluate sticking probability of the coated surface from the pressure ratio. The use of reference samples to calibrate the method is quite difficult. A better approach is a modellistic one, finding the dependency of pressure ratio on the average sticking probability, the pipe length and the section geometry and dimensions. Preliminary experimental results will be shown.

TUPCH182	Radiation Monitors as a Vacuum Diagnostic in the Room Temperature Parts of the LHC Straight Sections	radiation, vacuum, background, hadron	1441
	V. Talanov IHEP Protvino, Protvino, Moscow Region V. Baglin, T. Wijnands CERN, Geneva
	In the absence of collisions, inelastic interactions between protons and residual gas molecules are the main source of radiation in the room temperature parts of the LHC long straight sections. In this case the variations in the radiation levels will reflect the dynamics of the residual pressure distribution. Based on the background simulations for the long straight section of the LHC IP5 and on the current understanding of the residual pressure dynamics, we evaluate the possibility to use the radiation monitors for the purpose of the vacuum diagnostic, and we present the first estimates of the predicted monitor counts for different scenarios of the machine operation.

TUPCH183	H2 Equilibrium Pressure in a NEG-coated Vacuum Chamber as a Function of Temperature and H2 Concentration	vacuum, injection, instrumentation, collider	1444
	A. Rossi CERN, Geneva
	Non Evaporable Getter (NEG) coating is used in the LHC room- temperature sections to ensure a low residual gas pressure for its properties of distributed pumping, low outgassing and desorption under particle bombardment; and to limit or cure electron cloud build-up due to its low secondary electron emission. In certain regions of the LHC, and in particular close to the beam collimators, the temperature of the vacuum chamber is expected to rise due to energy deposition from particle losses. Gas molecules are pumped by the NEG via dissociation on the surface, sorption at the superficial sites and diffusion into the NEG bulk. In the case of hydrogen, the sorption is thermally reversible, causing the residual pressure to increase with NEG temperature and amount of H2 pumped. Measurements were carried out on a stainless steel chamber coated with TiZrV NEG as a function of the H2 concentration and the chamber temperature, to estimate the residual gas pressure in the collimator regions for various LHC operation scenarios, corresponding to different particle loss rates and times between NEG regenerations. The results are presented in this paper and discussed.

TUPCH195	The LHC Low Level RF	feedback, klystron, controls, injection	1471
	P. Baudrenghien, G. Hagmann, J.C. Molendijk, R. Olsen, A. Rohlev, V. Rossi, D. Stellfeld, D. Valuch, U. Wehrle CERN, Geneva
	The LHC RF consists in eight 400 MHz superconducting cavities per ring, with each cavity independently powered by a 300 kW klystron, via a circulator. The challenge for the Low Level is to cope with both very high beam current (more than 1A RF component) and excellent beam lifetime (emittance growth time in excess of 25 hours). For each cavity we have a Cavity Controller rack with two VME crates implementing a strong RF Feedback, a Tuner Loop with a new algorithm, a Klystron Ripple Loop and a Conditioning system. In addition each ring has a Beam Control system (four VME crates) including Frequency Program, Phase Loop, Radial Loop and Synchronization Loop. A Longitudinal Damper (dipole and quadrupole mode) acting via the 400 MHz cavities is included to reduce emittance blow-up due to filamentation following phase and energy errors at injection. Finally an RF Synchronization system implements the bunch into bucket transfer from the SPS into each LHC ring. When fully installed in 2007 the whole system will count over three hundreds home-designed VME cards of twenty-three different models installed in fourty-five VME crates.

TUPCH196	Digital Design of the LHC Low Level RF: the Tuning System for the Superconducting Cavities	controls, CERN, diagnostics, feedback	1474
	J.C. Molendijk, P. Baudrenghien, A. Butterworth, E. Ciapala, R. Olsen, F. Weierud CERN, Geneva R. Sorokoletov JINR, Dubna, Moscow Region
	The low level RF systems for the LHC are based extensively on digital technology, not only to achieve the required performance and stability but also to provide full remote control and diagnostics facilities needed in a machine where most of the RF system is inaccessible during operation. The hardware is based on modular VME but with additional low noise linear power supplies and a specially designed P2 backplane for timing distribution and fast data interchange. Extensive design re-use and the use of graphic FPGA design tools have streamlined the design process. A milestone was the test of the tuning system for the superconducting cavities. The tuning control module is based on a 2M gate FPGA with on-board DSP. Its design and functionality are described, including features such as automatic measurements of cavity characteristics and transient response of the tuning system. The tuner control is used as a test bed for LHC standard software components. A full 'vertical slice' from remote application down to the hardware has been tested. Work is ongoing on the completion of other modules and building up the software and diagnostics facilities needed for RF system commissioning.

TUPLS005	Preliminary Study of Using "Pipetron"-type Magnets for a Pre-accelerator for the LHC Collider	injection, dipole, lattice, SPS	1493
	G. De Rijk, L. Rossi CERN, Geneva H. Piekarz Fermilab, Batavia, Illinois
	One of the luminosity limitations of the LHC is the rather low injection energy (0.45 TeV) with respect to the collision energy (7 TeV). The magnetic multipoles in the main dipoles at low field and their dynamic behaviour are considered to limit the achievable bunch intensity and emittance. We report on a preliminary study to increase the injection energy to 1.5 TeV using a two beam pre-accelerator (LHCI) in the LHC tunnel. The LHCI is based on "Pipetron" magnets as originally proposed for the VLHC. The aim of the study is to assess the feasibility and to identify the critical processes or systems that need to be investigated and developed to render such a machine possible.

TUPLS006	Optics of a 1.5 TeV Injector for the LHC	dipole, optics, injection, quadrupole	1496
	J.A. Johnstone Fermilab, Batavia, Illinois
	A concept is being developed to install a second ring above the LHC to accelerate protons from 450 GeV to 1.5 TeV prior to injection into the LHC. The arc and dispersion suppressor optics of the LHC would be replicated in the injector using combined function 'transmission line' magnets orginally proposed for the VLHC. To avoid costly civil construction, in the straight sections housing detectors at least, the injector and LHC must share beampipes and some magnets through the detector portion of the straights. Creating the appropriate optics for these injector-LHC transition regions is very challenging: In addition to matching to the nominal LHC lattice functions at these locations, the changes in altitude of 1.1 m between the injector and LHC must be accomplished achromatically to avoid emittance blowup when the beams are transferred to the LHC.

TUPLS011	The Beam Screen for the LHC Injection Kicker Magnets	impedance, kicker, injection, vacuum	1508
	M.J. Barnes, F. Caspers, L. Ducimetière, N. Garrel, T. Kroyer CERN, Geneva
	The two LHC injection kicker magnet systems must each produce a kick of 1.2 T.m with a flattop duration variable up to 7.86 μs, and rise and fall times of less than 0.9 μs and 3 μs, respectively. Each system is composed of four 5 Ω transmission line kicker magnets with matched terminating resistors and pulse forming networks (PFN). The LHC beam has a high intensity, hence a beam screen is required in the aperture of the magnets This screen consists of a ceramic tube with conducting "stripes" on the inner wall. The stripes provide a path for the image current of the beam and screen the magnet ferrites against Wake fields. The stripes initially used gave adequately low beam impedance however stripe discharges occured during pulsing of the magnet: hence further development of the beam screen was undertaken. This paper presents options considered to meet the often conflicting needs for low beam impedance, shielding of the ferrite, fast field rise time and good electrical and vacuum behaviour.

TUPLS012	Dynamic Stresses in the LHC TCDS Diluter from 7 TeV Beam Loading	simulation, septum, extraction, LEFT	1511
	B. Goddard, A. Presland, W.J.M. Weterings CERN, Geneva L. Massidda CRS4, PULA
	In the event of an unsynchronised beam abort, the MSD extraction septum of the LHC beam dumping system is protected from damage by the TCDS diluter. The simultaneous constraints of obtaining sufficient beam dilution while ensuring the survival of the TCDS make the design difficult, with high thermally induced dynamic stresses occurring in the material needed to attenuate the particle showers induced by the primary beam impact. In this paper, full 3D simulations are described where the worst-case beam loading has been used to generate the local temperature rise and to follow the resulting time evolution of the mechanical stresses. The results and the accompanying design changes for the TCDS, to provide an adequate performance margin, are detailed.

TUPLS013	Protection of the LHC against Unsynchronised Beam Aborts	kicker, extraction, collimation, monitoring	1514
	B. Goddard, R.W. Assmann, E. Carlier, J.A. Uythoven, J. Wenninger, W.J.M. Weterings CERN, Geneva
	An unsynchronised beam abort in the LHC could cause major damage to other downstream accelerator components, in particular the extraction septum magnets, the experimental low-beta triplet magnet apertures and the tertiary collimators. Although the LHC beam dumping system includes design features to minimise their frequency, such unsynchronised aborts can arise from several sources and cannot be excluded. A system of protection devices comprising fixed and moveable passive diluters and collimators will be built to safely protect the downstream LHC aperture from the mis-directed bunches in case of such a failure. The sources of unsynchronised abort events are described, together with the requirements and design of the protection devices and their expected performance. The accompanying operational requirements and envisaged solutions are discussed, in particular the problem of ensuring the local orbit at the protection devices.

TUPLS014	Optics Flexibility and Dispersion Matching at Injection into the LHC	injection, optics, emittance, controls	1517
	A. Koschik, H. Burkhardt, B. Goddard, Y. Kadi, V. Kain, V. Mertens, T. Risselada CERN, Geneva
	The LHC requires very precise matching of transfer line and LHC optics to minimise emittance blow-up and tail repopulation at injection. The recent addition of a comprehensive transfer line collimation system to improve the protection against beam loss has created additional matching constraints and consumed a significant part of the flexibility contained in the initial optics design of the transfer lines. Optical errors, different injection configurations and possible future optics changes require however to preserve a certain tuning range. Here we present methods of tuning optics parameters at the injection point by using orbit correctors in the main ring, with the emphasis on dispersion matching. The benefit of alternative measures to enhance the flexibility is briefly discussed.

TUPLS015	Calibration Measurements of the LHC Beam Dumping System Extraction Kicker Magnets	extraction, kicker, dumping, CERN	1520
	J.A. Uythoven, F. Castronuovo, L. Ducimetière, B. Goddard, G. Gräwer, F. Olivieri, L. Pereira, E. Vossenberg CERN, Geneva
	The LHC beam dumping system must protect the LHC machine from damage by reliably and safely extracting and absorbing the circulating beams when requested. Two sets of 15 extraction kicker magnets form the main active part of this system. They have been produced, tested and calibrated by measuring the integrated magnetic field and the magnet current at different beam energies. The calibration data have been analysed, and the critical parameters are compared with the specifications. Implications for the configuration, control and operation of the beam dumping system are discussed.

TUPLS017	Optics Study for a Possible Crystal-based Collimation System for the LHC	collimation, injection, proton, extraction	1526
	R.W. Assmann, S. Redaelli, W. Scandale CERN, Geneva
	The use of bent crystals as primary collimators has been long proposed as an option to improve the cleaning efficiency of the LHC betatron and momentum collimation systems. These systems are presently based on two-stage collimation with amorphous scatterers and absorbers. Crystals are expected to help by channeling and extracting the halo particles with large angles, resulting in higher cleaning efficiency. Independent of ongoing studies for crystal qualifications (not reported here), it is important to understand the required deflection angles and the possible locations of absorbers for the LHC layout. Optics studies have been performed in order to specify the required angles for various LHC beam energies and possible locations of absorbers for the deflected halo beam. A possible layout for crystal-assisted collimation at the LHC is discussed, aiming for a solution which would not change the LHC layout but would make use of the existing collimator location.

TUPLS018	Collimation Efficiency during Commissioning	collimation, proton, insertion, betatron	1529
	C.B. Bracco, R.W. Assmann, A. Ferrari, S. Redaelli, G. Robert-Demolaize, M. Santana-Leitner, V. Vlachoudis, Th. Weiler CERN, Geneva
	The design of the LHC collimation system naturally focused on understanding and maximizing the ultimate performance with all collimators in place. However, for the commissioning of the LHC it is important to analyze the collimation efficiency with certain subsets of collimators, with increased collimation gaps and relaxed set-up tolerances. Special studies on halo tracking and energy deposition have been performed in order to address this question. The expected cleaning performance and intensity limits are discussed for various collimation scenarios as they might be used during commissioning and initial operation of the LHC.

TUPLS019	Critical Halo Loss Locations in the LHC	optics, injection, proton, insertion	1532
	G. Robert-Demolaize, R.W. Assmann, C.B. Bracco, S. Redaelli, Th. Weiler CERN, Geneva
	The requirements on cleaning efficiency in the LHC are two to three orders of magnitude beyond the needs at existing super-conducting colliders. The LHC will therefore operate in unknown territory, which can only be assessed by powerful simulation tools. Such tools have been developed at CERN over the last years, making it possible to perform detailed simulations of the LHC cleaning processes and multi-turn loss patterns around the LHC ring. The simulation includes all collimators, diluters and absorbers in the LHC. Proton loss maps are generated with a 10 cm resolution, which allows performing advanced studies for quenches of super-conducting magnets along with the analysis of the deposited energy in the machine elements. The critical locations of beam halo losses are discussed, both for the ideal machine and for various scenarios of closed-orbit distortion and beta-beating. From these results it can be shown that it is sufficient to use a limited number of BLM's for the setup and optimization of the LHC collimation system.

TUPLS022	Experimental Study of Crystal Channeling at CERN-SPS for Beam-halo Cleaning	proton, collimation, alignment, SPS	1538
	M. Fiorini, P. Dalpiaz, V. Guidi UNIFE, Ferrara G. Ambrosi INFN-PG, Perugia R.W. Assmann, I. Efthymiopoulos, L. Gatignon, W. Scandale CERN, Geneva C. Biino INFN-Torino, Torino Y.A. Chesnokov IHEP Protvino, Protvino, Moscow Region Yu.M. Ivanov PNPI, Gatchina, Leningrad District R. Santacesaria INFN-Roma, Roma A.M. Taratin JINR, Dubna, Moscow Region A. Vomiero INFN/LNL, Legnaro, Padova
	An efficient and robust collimation system is mandatory for any superconducting hadron collider, in particular for the LHC, which will store a beam of unprecedented high intensity and energy. The usage of highly efficient and short primary bent-crystal collimators might be a possibility for reaching nominal and ultimate LHC intensity. Over the last years, groups in Russia (St. Petersburg) and Italy (Ferrara) have developed crystal production methods, which considerably improve the crystal quality. In view of the crystal-collimation experiments at the Tevatron and of the potential improvement compared with the phas·10^-1 LHC collimation system, considering the recent progress in crystal technology, we proposed experiments for crystal characterization in the SPS beam lines. Major objectives will be: 1) qualification of the new crystals to be used in the Tevatron; 2) measuring the channeling efficiency of long crystals with 1 mrad and/or 8 mrad bending angle; and 3) comparison of loss patterns around the ring for a crystal with one for amorphous material. In this paper we will report the progress towards the SPS experiment.

TUPLS123	Design of the LHC Beam Dump Entrance Window	kicker, vacuum, CERN, proton	1792
	R. Veness, B. Goddard, S.J. Mathot, A. Presland CERN, Geneva L. Massidda CRS4, PULA
	7 TeV proton beams from the LHC are ejected through a 600 m long beam dump transfer line vacuum chamber to a beam dump block. The dump block is contained within an inert gas-filled vessel to prevent a possible fire risk. The dump vessel and transfer line are separated by a 600 mm diameter window, which must withstand both the static pressure load and thermal shock from the passage of the LHC beam. In a previous paper* the functional requirements and conceptual design of this window were outlined. This paper describes the analysis leading to the final design of the window. The choice of materials is explained and tests performed on the prototype window are summarized. *A. Presland et al. "A large diameter entrance window for the LHC beam dump line". Proc. PAC 2005, 1698-1700.

TUPLS126	Interaction of the CERN Large Hadron Collider (LHC) Beam with Carbon Collimators	target, proton, simulation, heavy-ion	1798
	N.A. Tahir, D. Hoffmann GSI, Darmstadt Y. Kadi, R. Schmidt CERN, Geneva R. Piriz Universidad de Castilla-La Mancha, Ciudad Real A. Shutov IPCP, Chernogolovka, Moscow region
	The LHC will operate at 7 TeV with a luminosity of 10³⁴ cm-2s-1. Each beam will have 2808 bunches, with nominal intensity per bunch of 1.1x10¹¹ protons. The energy stored in each beam of 362 MJ. In a previous paper the mechanisms causing equipment damage in case of a failure of the machine protection system was discussed, assuming that the entire beam is deflected into a copper target. Another failure scenario is the deflection of beam into carbon material. Carbon collimators and beam absorbers are installed in many locations around the LHC to diffuse or absorb beam losses. Since their jaws are close to the beam, it is very likely that they are hit first when the beam is accidentally deflected. Here we present the results of two-dimensional hydrodynamic simulations of the heating of a solid carbon cylinder irradiated by the LHC beam with nominal parameters, carried out using the BIG-2 computer code* while the energy loss of the 7 TeV protons in carbon is calculated using the well known FLUKA code*. Our calculations suggest that the LHC beam may penetrate up to 10 m in solid carbon, resulting in a substantial damage of collimators and beam absorbers. V. E. Fortov et al. Nucl. Sci. Eng. 123 (1996) 169. **A. Fasso et al. The physics models of FLUKA: status and recent development, CHEP 2003, La Jolla, California, 2003.

TUPLS127	Permanent Deformation of the LHC Collimator Jaws Induced by Shock Beam Impact: an Analytical and Numerical Interpretation	CERN, proton, collimation, simulation	1801
	A. Bertarelli, O. Aberle, R.W. Assmann, A. Dallocchio, T. Kurtyka, M. Magistris, M. Mayer, M. Santana-Leitner CERN, Geneva
	Inspections carried out on jaws of the LHC collimator prototype, which underwent the 450 GeV robustness test in CERN TT40 extraction line, revealed no visible damage, except a permanent deformation of the jaw metal support of ~300 um. An explanation of this phenomenon is proposed in this paper. The temperature increase on the metal support induced by the thermal shock, though limited to ~70°C, led to a sudden expansion of the copper-based support which was partially prevented by the inertia of the material itself, thus generating compressive stresses exceeding the elastic limit of OFE-copper. An analytical assessment of the process, followed by a finite-element transient elasto-plastic analysis, is presented. Numerical results are in good agreement with measured data. In order to confirm this analysis, a special test on series production jaws, where OFE-copper has been replaced by Dispersion Strengthened Copper (Glidcop�), is scheduled for the second half of 2006.

TUPLS128	A New Analytical Method to Evaluate Transient Thermal Stresses in Cylindrical Rods Hit by Proton Beams	target, proton, CERN, simulation	1804
	A. Dallocchio, A. Bertarelli, T. Kurtyka CERN, Geneva
	This paper presents an analytical solution for the thermo-mechanical problem of CNGS target rods rapidly heated by fast extracted high energy proton beams. The method allows the computation of the dynamic transient elastic stresses induced by a proton beam hitting off-axis the target. The studies of such dynamic thermo-mechanical problems are usually made via numerical methods. However, an analytical approach is also needed to quickly provide reference solutions for the numerical results. An exact solution for the temperature field is first obtained, using Fourier-Bessel series expansion. Quasi-static thermal stresses are then computed as a function of the calculated temperature distribution, making use of the thermoelastic displacement potential for the equivalent isothermal two-dimensional stress problem. Finally, the contribution of dynamic stresses due to longitudinal and bending stress waves is determined by means of the modal summation method. This method can be effectively applied to any solid having cylindrical shape, made out of isotropic elastic material.

TUPLS130	Comparison between Measured and Simulated Beam Loss Patterns in the CERN SPS	SPS, simulation, beam-losses, proton	1810
	S. Redaelli, G. Arduini, R.W. Assmann, G. Robert-Demolaize CERN, Geneva
	A prototype of an LHC collimator has been tested with proton beams at the CERN SPS. The interaction of the circulating proton beam with the carbon collimator jaws generated showers that were lost in the downstream SPS aperture. The measured beam loss patterns are compared in detail with the results of dedicated loss simulations. The simulation package includes (1) a 6D particle tracking through the SPS lattice; (2) the scattering interaction of protons with the collimator jaw material; (3) the time-dependent displacement of the collimator jaws with respect to the beam orbit; (4) a detailed aperture model of the full SPS ring. It is shown that the simulation tools can reliably predict the measured location of losses. This provides an important assessment of the simulation tools in view of the LHC beam loss studies.

TUPLS135	Technical Infrastructure Monitoring at CERN	monitoring, CERN, controls, site	1822
	J. Stowisek, T.R. Riesco, A.S. Suwalska CERN, Geneva
	The Technical Infrastructure Monitoring system (TIM) is used to survey and control CERN's technical services from the CERN Control Centre (CCC). The system's primary function is to provide CCC operators with reliable real-time information about the state of the laboratory's extensive and widely distributed technical infrastructure. TIM is also used to monitor all general services required for the operation of the accelerator complex and the experiments. A flexible data acquisition mechanism allows TIM to interface with a wide range of technically diverse installations, using industry standard protocols wherever possible and custom designed solutions where needed. The complexity of the data processing logic, including persistence, logging, alarm handling, command execution and the evaluation of data-driven business rules is encapsulated in the system's business layer. Users benefit from a suite of advanced graphical applications adapted to operations (synoptic views, alarm consoles, data analysis tools etc.), system maintenance and support. Complementary tools for configuration data management and historical data analysis will be available before the start-up of the LHC in 2007.

WEOBPA02	LEIR Commissioning	ion, injection, controls, linac	1876
	C. Carli, P. Beloshitsky, L. Bojtar, M. Chanel, K. Cornelis, B. Dupuy, J. Duran-Lopez, T. Eriksson, S.S. Gilardoni, D. Manglunki, E. Matli, S. Maury, C. Oliveira, S. Pasinelli, J. Pasternak, F. Roncarolo, G. Tranquille CERN, Geneva
	The Low Energy Ion Ring (LEIR) is a central piece of the injector chain for LHC ion operation, transforming long Linac 3 pulses into high density bunches needed for LHC. LEIR commissioning is scheduled to be completed at the time of the conference. A review of LEIR commissioning highlighting expected and unexpected problems and actions to tackle them will be given.
	Transparencies

WEXFI02	Observation and Modeling of Electron Cloud Instability	electron, RHIC, KEK, proton	1887
	K.C. Harkay ANL, Argonne, Illinois
	This presentation will review experimental results and the state of the art in the analysis and simulation of the electron cloud instability in hadron and positron storage rings.
	Transparencies

WEPCH043	On the Implementation of Experimental Solenoids in MAD-X and their Effect on Coupling in the LHC	coupling, optics, quadrupole, injection	2011
	A. Koschik, H. Burkhardt, T. Risselada, F. Schmidt CERN, Geneva
	The betatron coupling introduced by the experimental solenoids in the LHC is small at injection and negligible at collision energy. We present a study of these effects and look at possible corrections. Additionally we report about the implementation of solenoids in the MAD-X program. A thin solenoid version is also made available for tracking purposes.

WEPCH044	Interaction Region with Slim Quadrupoles	quadrupole, luminosity, interaction-region, beam-beam-effects	2014
	E. Laface, R. Ostojic, W. Scandale, D. Tommasini CERN, Geneva C. Santoni Université Blaise Pascal, Clermont-Ferrand
	An optical performance's improvement of the interaction region can be obtained with the addition of new quadrupoles in the forward detectors area. Such scenario would allow decreasing the $β*$ below the nominal value. The basic concept consists in using quadrupoles to break the quadratic behavior of $β$ in the free space between the IP and the IR triplets. In this new configuration we present the performance improvements and the hardware requirements.

WEPCH045	Sorting Strategies for the Arc Quadrupoles of the LHC	quadrupole, optics, resonance, simulation	2017
	Y. Papaphilippou, A.M. Lombardi CERN, Geneva
	The variation in the field gradient of the LHC arc quadrupoles can not be corrected independently by the dedicated trim quadrupole circuits. This may result to a beta function beating larger than the one accepted by the machine budget. In this respect, sorting strategies for the installation of these magnets were implemented in order to eliminate this effect, as locally as possible. Special care was taken for quadrupoles whose warm measurements showed large gradient errors due to an excessive magnetic permeability. The figures of merit used in the sorting and the results obtained for all 8 sectors of the LHC are detailed. The global optics function beating foreseen, as computed by both analytical estimates and simulations with MAD-X are finally presented.

WEPCH047	Procedures and Accuracy Estimates for Beta-beat Correction in the LHC	quadrupole, simulation, coupling, power-supply	2023
	R. Tomas, O.S. Brüning, S.D. Fartoukh, M. Giovannozzi, Y. Papaphilippou, F. Zimmermann CERN, Geneva R. Calaga, S. Peggs BNL, Upton, Long Island, New York F. Franchi GSI, Darmstadt
	The LHC aperture imposes a tight tolerance of 20% on the maximum acceptable beta-beat in the machine. An accurate knowledge of the transfer functions for the individually powered insertion quadrupoles and techniques to compensate beta-beat are key prerequisites for successful operation with high intensity beams. We perform realistic simulations to predict quadrupole errors in LHC and explore possible ways of correction to minimize beta-beat below the 20% level.

WEPCH048	Measurement and Modeling of Magnetic Hysteresis in the LHC Superconducting Correctors	CERN, sextupole, injection, controls	2026
	W. Venturini Delsolaro, L. Bottura, Y. C. Chaudhari, M. Karppinen CERN, Geneva N.J. Sammut University of Malta, Faculty of Engineering, Msida
	The Large Hadron Collider, now under construction at CERN, relies heavily on superconducting magnets for its optics layout: besides the main magnets, almost all the correcting magnets are superconducting. Along with clear advantages, this brings about complications due to the effects of persistent currents in the superconducting filaments. Correcting magnets that trim key beam parameters or compensate field errors of the main magnets (among others those due to hysteresis), are in their turn hysteretic. The measured magnetic hysteresis and its possible influence on accelerator operation will be presented, in particular the real-time compensation of decay and snapback in the main magnets, and the reproducibility between runs. A detailed characterization of minor hysteresis loops is given, as well as degaussing cycles and modeling work.

WEPCH092	Dynamical Aperture Studies for the CERN LHC: Comparison between Statistical Assignment of Magnetic Field Errors and Actual Measured Field Errors	quadrupole, simulation, optics, dipole	2128
	M. Giovannozzi, S.D. Fartoukh, S.S. Gilardoni, J.-B. Jeanneret, A.M. Lombardi, Y. Papaphilippou, T. Risselada, R. de Maria CERN, Geneva
	It is customary to evaluate the performance of a circular particle accelerator by computing the dynamical aperture, i.e., the domain in phase space where bounded single-particle motion occurs. In the case of the LHC the dynamical aperture computation is performed by assuming a statistical distribution of the magnetic field errors of various magnets' classes: the numerical computations are repeated for a given set of realisations of the LHC ring. With the progress in the magnet production and allocation of the available positions in the ring, the statistical approach has to be replaced by the computation of one single configuration, namely the actual realisation of the machine. Comparisons between the two approaches are presented and discussed in details.

WEPCH093	Parameter Scans and Accuracy Estimates of the Dynamic Aperture of the CERN LHC	dynamic-aperture, simulation, CERN, dipole	2131
	M. Giovannozzi, E. McIntosh CERN, Geneva
	Techniques to make use of large distributed computing facilities allow for denser parameter scans of the dynamical aperture, i.e., the domain in phase space where bounded single-particle motion prevails. Moreover, one can also increase the number of 'seeds' each of which represents a possible realisation of multipolar components around the machine. In this paper the dependence of the dynamical aperture on the step size of the grid of initial conditions and on the number of seeds is studied. Estimates on the accuracy of the dynamic aperture are derived and the definition of an improved protocol for numerical simulations is presented.

WEPCH094	An Early Beam Separation Scheme for the LHC	luminosity, separation-scheme, dipole, beam-beam-effects	2134
	J.-P. Koutchouk, G. Sterbini CERN, Geneva
	The high nominal luminosity of the LHC requires a large number of bunches spaced by about 7.5 m. To prevent more than one head-on collision in each interaction region, a crossing angle of 0.285 mrad is necessary. A side effect of this crossing angle is the increase of the effective transverse beam cross-section, thereby decreasing the luminosity by some 16%. For the LHC upgrade, depending on the focusing scenarios, this loss significantly increases and largely offsets the potential gain of a stronger focusing. In this paper we analyze a strategy to circumvent this difficulty, based an early beam separation using small dipoles placed at a few meters from the interaction point, deep inside the detectors. This allows quasi co-linear head-on collisions at the crossing point only. From the beam dynamics point of view, the essential constraint is to control the long-range beam-beam interactions in a scenario where the normalized beam separation is not constant. In this paper the criteria of the analysis and the performance improvement obtained with the scheme are discussed. The strength of the dipoles is estimated as well as the impact on the detectors structure.

WEPCH095	Models to Study Multi-bunch Coupling through Head-on and Long-range Beam-beam Interactions	coupling, damping, simulation, CERN	2137
	T. Pieloni, W. Herr CERN, Geneva
	In the LHC almost 6000 bunches will collide in four interaction points where they experience head-on as well as clustered long range interactions. These lead to a coupling between all bunches and coherent beam-beam effects. For two colliding bunches this is well understood. However, for a large number of bunches colliding with different collision patterns, it results in a complex spectrum of oscillation frequencies with consequences for beam measurements and Landau damping. To study the coherent beam-beam modes, three complementary models have been developped and will be described in this report. Two of these methods rely on self-consistent multi-bunch and multi-particle tracking while the third is a semi-analytic model based on a complex matrix algorithm. The three methods together provide useful information about the beam-beam coupling of multi bunch beams and together provide a deeper insight into the underlying physics.

WEPCH104	Observation of the Long-range Beam-beam Effect in RHIC and Plans for Compensation	RHIC, simulation, beam-losses, emittance	2158
	W. Fischer, R. Calaga BNL, Upton, Long Island, New York U. Dorda, J.-P. Koutchouk, F. Zimmermann CERN, Geneva A.C. Kabel SLAC, Menlo Park, California J. Qiang LBNL, Berkeley, California V.H. Ranjibar, T. Sen Fermilab, Batavia, Illinois J. Shi KU, Lawrence, Kansas
	At large distances the electromagnetic field of a wire is the same as the field produced by a bunch. Such a long-range beam-beam wire compensator was proposed for the LHC, and single beam tests with wire compensators were successfully done in the SPS. RHIC offers the possibility to test the compensation scheme with colliding beams. We report on measurements of beam loss measurements as a function of transverse separation in RHIC at injection, and comparisons with simulations. We present a design for a long-range wire compensator in RHIC.

WEPCH138	Simulations of Long-range Beam-beam Interaction and Wire Compensation with BBTRACK	simulation, RHIC, luminosity, emittance	2245
	U. Dorda, F. Zimmermann CERN, Geneva
	We present weak-strong simulation results for the effect of long-range beam-beam collisions in LHC, SPS, RHIC and DAFNE, as well as for proposed wire compensation schemes or wire experiments, respectively. In particular, we discuss details of the simulation model, instability indicators, the effectiveness of compensation, the difference between nominal and PACMAN bunches for the LHC, beam experiments, and wire tolerances. The simulations are performed with the new code BBTRACK.

WEPCH139	WISE: An Adaptative Simulation of the LHC Optics	simulation, CERN, quadrupole, power-supply	2248
	P. Hagen, M. Giovannozzi, J.-P. Koutchouk, T. Risselada, S. Sanfilippo, E. Todesco, E.Y. Wildner CERN, Geneva
	The LHC beam dynamics requires a tight control of the magnet field quality and geometry. As the production of the magnets advances, decisions have to be made on the acceptance of possible imperfections. To ease decision making, an adaptative model of the LHC optics has been built, based on the current information available (e.g. magnetic measurements at warm or cold, magnet allocation to machine slots) as well as on statistical evaluations for the missing information (e.g. magnets yet to be built, measured, or for non-allocated slots). The uncertainties are included: relative and absolute measurement errors, warm-to-cold correlations for the fraction of magnets not measured at cold, hysteresis and power supply accuracy. A pre-processor generates instances of the LHC ring for the MADX program, with the possibility of selecting various error sources. A post-processor computes ranges for relevant beam optics parameters and distributions. This approach has been applied to the expected beta-beating, to the possible impact of permeability issues in some quadrupole collars, to the geometrical displacements of the multipolar correctors and to prioritize the magnetic measurement programme.

WEPCH154	SPS Access System Upgrade	SPS, controls, extraction, injection	2287
	E. Manola-Poggioli, PL. Lienard, T. Pettersson CERN, Geneva
	The present SPS access system is not entirely compatible with the formal requirements of the French Radioprotection Authorities, and a project has been launched to remedy this situation. The upgrade project is split into three phases that will be implemented, in the present planning, in the shutdowns 2006, 2007 and after the first physics run of the LHC, respectively. This paper presents the results of the safety study, the upgrade strategy and the architecture of the upgraded system.

WEPCH156	CERN Safety Alarms Monitoring System (CSAM)	CERN, monitoring, site, controls	2293
	E. Manola-Poggioli, L. Scibile CERN, Geneva
	The CERN Safety Alarms Monitoring (CSAM) system is designed to aquire and transmit reliably to the CERN Fire Brigade all the alarms generated by a large number of safety alarm equipment distributed around the sites and in the underground. The quality and accuracy of the information provided by CSAM is crucial to permit a quick and efficient intervention by the Fire Brigade. The CSAM projet was launched in 1999 to replace the previous alarm system which used obsolete technology and operator devices. The new system is in operation since 2005 and 2/3 of all alarm equipement on the CERN sites are now handled by the new system. The migration/installation process is is expected to terminate in May 2006. This paper presents the system architecture, the deployment process and the return of experience in the accelerator environment.

WEPLS081	Modifications to the SPS LSS6 Septa for LHC and the SPS Septa Diluters	extraction, SPS, septum, proton	2565
	J. Borburgh, B. Balhan, B. Goddard, Y. Kadi CERN, Geneva
	The Large Hadron Collider required the modification of the existing extraction channel in the long straight section (LSS) 6 of the CERN Super Proton Synchrotron (SPS), including the suppression of the electrostatic wire septa. The newly set up fast extraction will be used to transfer protons at 450 GeV/c as well as ions via the 2.9 km long transfer line TI 2 to Ring 1 of the LHC. The girder of the existing SPS DC septa was modified to accommodate a new septum protection element. Changes were also applied to the septum diluter in the fast extraction channel in SPS LSS4, leading to the other LHC ring and the CNGS facility. The requirements and the layout of the new LSS6 extraction channel will be described including a discussion of the design and performance of the installed septum diluters.

WEPLS083	Consolidation of the 45-year-old CERN PS Main Magnet System	radiation, CERN, radioactivity, vacuum	2571
	Th. Zickler, D. Bodart, W. Kalbreier, K.H. Mess, A. Newborough CERN, Geneva
	After a major coil insulation breakdown on two of the 45-year-old CERN PS main magnets in 2003, an extensive magnet consolidation program has been launched. This article reviews the analysis of the magnet state before the repair and the applied major improvements. An overview is given of the production of the new components, the actual refurbishment and the commissioning of the main magnet system after 18 months shut down.

WEPLS097	Random Errors in Superconducting Dipoles	dipole, multipole, RHIC, simulation	2601
	B. Bellesia, E. Todesco CERN, Geneva C. Santoni Université Blaise Pascal, Clermont-Ferrand
	The magnetic field in a superconducting magnet is mainly determined by the position of the conductors. Hence, the main contribution to the random field errors comes from random displacement of the coil with respect to its nominal position. Using a Monte-Carlo method, we analyze the measured random field errors of the main dipoles of the LHC, Tevatron, RHIC and HERA projects in order to estimate the precision of the conductor positioning reached during the production. The method can be used to obtain more refined estimates of the random components for future projects.

WEPLS098	Experience with the Quality Assurance of the Superconducting Electrical Circuits of the LHC Machine	dipole, pick-up, quadrupole, octupole	2604
	D. Bozzini, V. Chareyre, K.H. Mess, S. Russenschuck CERN, Geneva A. Kotarba, S. Olek HNINP, Kraków
	The coherence between the powering reference database and the Electrical Quality Assurance (ELQA) is guaranteed on the procedural level. However, a challenge remains the coherence between the database, the magnet test and assembly procedures, and the connection of all superconducting circuits of the LHC. In this paper, the methods, tooling, and procedures for the ELQA during the assembly phase of the LHC will be presented in view of the practical experience gained in the LHC tunnel. The parameters measured at ambient temperature such as the dielectric insulation and the impedance transfer function of assembled circuits will be discussed. Some examples of detected polarity errors and the treatment of non-conformities will be presented.

WEPLS099	Fault Detection and Identification Methods Used for the LHC Cryomagnets and Related Cabling	impedance, diagnostics, cryogenics, superconducting-magnet	2607
	D. Bozzini, F. Caspers, V. Chareyre, Y. Duse, T. Kroyer, R. Lopez, A. Poncet, S. Russenschuck CERN, Geneva
	Several non-standard methods for electrical fault location have been successfully developed and tested. As part of the electrical quality assurance program, certain wires have to be subjected to a (high) DC voltage for the testing of the insulation. With the time difference of spark-induced electromagnetic signals measured with an oscilloscope, fault localization within a ± 10 cm range has been achieved. Another method used and adapted for the particular needs, was the synthetic pulse time-domain reflectometry (TDR) by means of a vector network analyzer. This instrument has also been applied as a low frequency sweep impedance analyzer in order to measure fractional capacities of cable assemblies where TDR was not applicable.

WEPLS100	Performance of LHC Main Dipoles for Beam Operation	dipole, CERN, target, controls	2610
	G. De Rijk, M. Bajko, L. Bottura, M.C.L. Buzio, V. Chohan, L. Deniau, P. Fessia, J. Garcia Perez, P. Hagen, J.-P. Koutchouk, J. Kozak, J. Miles, M. Missiaen, M. Modena, P. Pugnat, V. Remondino, L. Rossi, S. Sanfilippo, F. Savary, A.P. Siemko, N. Smirnov, A. Stafiniak, E. Todesco, D. Tommasini, J. Vlogaert, C. Vollinger, L. Walckiers, E.Y. Wildner CERN, Geneva
	At present about 75% of the main dipoles for the LHC have been manufactured and one of the three cold mass assemblers has already completed the production. More than two third of the 1232 dipoles needed for the tunnel have been tested and accepted. In this paper we mainly deal with the performance results: the quench behavior, the magnetic field quality, the electrical integrity quality and the geometry features will be summarized. The variations in performance associated with different cold mass assemblers and superconducting cable origins will be discussed.

WEPLS101	First Computation of Parasitic Fields in LHC Dipole Magnet Interconnects	dipole, CERN, quadrupole, multipole	2613
	A. Devred, B. Auchmann, Y. Boncompagni, V. Ferapontov, J.-P. Koutchouk, S. Russenschuck, T. Sahner, C. Vollinger CERN, Geneva
	The Large Hadron Collider (LHC), now under construction at CERN, will rely on about 1600 main superconducting dipole and quadrupole magnets and over 7400 superconducting corrector magnets distributed around the eight sectors of the machine. Each type of magnets is powered by dedicated superconducting busbars running along each sector and passing through the iron yokes of the main dipole and quadruple magnets. In the numerous magnet interconnects, the busbars are not magnetically shielded from the beam pipes and produce parasitic fields that can affect beam optics. We review the 3D models which have been built with the ROXIE software package to evaluate these parasitic fields and we discuss the computation results and their potential impacts on machine performance.

WEPLS102	The Construction of the Superconducting Matching Quadrupoles for the LHC Insertions	quadrupole, insertion, CERN, alignment	2616
	R. Ostojic, P. Canard, N. Catalan-Lasheras, G. Kirby, J.C. Perez, H. Prin, W. Venturini Delsolaro CERN, Geneva
	After several years of intensive effort, the construction of the superconducting matching quadrupoles for the LHC insertions is nearing completion. We retrace the main events of the project from the initial development of quadrupole magnets of several types to the series production of over 100 complex cryo-magnets, and report on the techniques developed for steering of the production. The main performance parameters for the full series, such as quench training, field quality and magnet geometry are presented. The experience gained in the production of these special superconducting magnets is of considerable value for further development of the LHC insertions.

WEPLS103	The Field Description Model for the LHC Quadrupole Superconducting Magnets	quadrupole, CERN, controls, insertion	2619
	N.J. Sammut, L. Bottura, S. Sanfilippo CERN, Geneva J. Micallef University of Malta, Faculty of Engineering, Msida
	The LHC control system requires an accurate forecast of the magnetic field and the multipole field errors to reduce the burden on the beam-based feed-back. The Field Description for the LHC (FIDEL) is the core of this forecast system and is based on the identification and physical decomposition of the effects that contribute to the total field in the magnet apertures. The effects are quantified using the data obtained from series magnetic measurements at CERN and they are consequently modelled empirically or theoretically depending on the complexity of the physical phenomena. This paper presents a description of the methodology used to model the field of the LHC magnets particularly focusing on the results obtained for the LHC Quadrupoles (MQ, MQM and MQY).

WEPLS104	The Dependence of the Field Decay on the Powering History of the LHC Superconducting Dipole Magnets	dipole, injection, CERN, collider	2622
	N.J. Sammut, L. Bottura, S. Sanfilippo CERN, Geneva J. Micallef University of Malta, Faculty of Engineering, Msida
	The decay amplitude of the allowed multipoles in the LHC dipoles is expected to perturb the beam stability during the injection phase and is strongly dependent on the powering history of the magnet. The effect is particularly large for the pre-cycle nominal flat-top current and duration. With possible prospects of having different genres of cycles during the LHC operation, the powering history effect must be taken into account in the Field Description Model for the LHC (FIDEL) and must hence be corrected for during machine operation. This paper presents the results of the modelling of this phenomenon. We also discuss the statistic of magnetic measurements required to guarantee that the current history effect is predicted within the specified accuracy.

WEPLS105	Performance of the LHC Arc Superconducting Quadrupoles towards the End of their Series Fabrication	quadrupole, CERN, factory, dipole	2625
	T. Tortschanoff, P. Hagen, M. Modena, L. Rossi, S. Sanfilippo, K. M. Schirm, E. Todesco, E.Y. Wildner CERN, Geneva R. Burgmer, H.-U. Klein, D. Krischel, B. Schellong, P. Schmidt ACCEL, Bergisch Gladbach M. Durante, A. Payn, F. Simon CEA, Gif-sur-Yvette
	The fabrication of the 408 main arc quadrupole magnets and their cold masses will come to an end in summer 2006. A rich collection of measurement and test data has been accumulated and their analysis is presented in this paper. These data cover the fabrication and the efficiency in the use of the main components, the geometrical measurements and the achieved dimensional precision, the warm magnetic measurements in the factory and the performance at cold conditions, especially the training behaviour. The scrap rate of the NbTi/Cu conductor as well as that of other components turned out to be acceptably low and the quench performance measured was in general very good. Most quadrupoles measured so far exceeded the operating field gradient with one or no quench. The multipole content at cold was measured for a limited numbers of quadrupoles as far as needed for verifying the warm-to-cold correlation. From the point of view of field quality, all quadrupoles could be accepted for the machine and the measures taken to overcome the problem of a too high permeability of a batch of collars are discussed.

WEPLS106	Design, Performance and Series Production of Superconducting Trim Quadrupoles for the Large Hadron Collider	CERN, quadrupole, target, insertion	2628
	M. Karppinen, C. Boyer, J.-M. Castro, H.A. Garcia de Sousa Lopes, C. Giloux, J. Mazet, G. Mugnai, V. Remondino, D. Rodrigues, W. Venturini Delsolaro, R. Wolf CERN, Geneva G. Gaggero, L. Loche, M. Tassisto ANSALDO Energia, Magnet & Special Product Division, Genova P. Khare, A. Puntambekar RRCAT, Indore (M.P.)
	The Large Hadron Collider (LHC) will be equipped with several thousands of superconducting corrector magnets. Among the largest ones are the superconducting trim quadrupoles (MQTL). These twin-aperture magnets with a total mass of up to 1700 kg have a nominal gradient of 129 T/m at 1.9 K and a magnetic length of 1.3 m. Sixty MQTL are required for the LHC, 36 operating at 1.9 K in and 24 operating at 4.5 K. The paper describes the design features, and reports the measured quench performance and magnetic field quality of the production magnets. The MQTL magnet production is shared between CERN and industry. This sharing is simplified due to the modular construction, common to all twin-aperture correctors.

WEPLS107	Comparative Study of Inter-strand Coupling Current Models for Accelerator Magnets	dipole, coupling, CERN, GSI	2631
	R. de Maria, B. Auchmann, S. Russenschuck CERN, Geneva
	"Inter-Strand Coupling Currents" (ISCCs) contribute to field errors and losses in Rutherford-type superconducting cables in the time^- transient regime. The field change induces eddy currents in loops formed by the superconducting twisted strands and the resistive matrix. In the ROXIE program two models are implemented to simulate ISCCs in a magnet cross-section: A network model uses an electric circuit to represent the geometry of the twisted strands and their resistive contacts; an analytical model simplifies the network equations to determine an equivalent cable magnetization from an average field sweep over the cable. The implementation of the models in ROXIE allows to combine them with models for "Persistent Currents" and "Inter-Filament Coupling Currents". The non-linear iron yoke can be taken into account as well. The predictions of different ISCC models with regard to losses and field errors are compared for two design versions of the LHC main dipole. We find that as far as field quality is concerned, the models perform equally well. As for losses, however, the analytical model cannot capture the complexity of the problem and computes lower losses than the network model.

WEPLS109	Test Results of Fermilab-built Quadrupoles for the LHC Interaction Regions	quadrupole, alignment, interaction-region, target	2637
	M.J. Lamm, R. Bossert, J. DiMarco, SF. Feher, A. Hocker, J.S. Kerby, A. Nobrega, I. Novitski, R. Rabehl, P. Schlabach, J. Strait, C. Sylvester, M. Tartaglia, J. Tompkins, G. Velev, A.V. Zlobin Fermilab, Batavia, Illinois
	The US-LHC Accelerator Project has recently completed the manufacturing and testing of the Q2 optical elements for the LHC interaction region final focus. Each Q2 element consists of two identical quadrupoles (MQXB) with a dipole orbit corrector (MQXB). The Fermilab designed MQXB has a 70 mm aperture and a peak operating gradient of 215 T/m. This paper summarizes the test results for the MQXB program with emphasis on quench performance and alignment studies.

WEPLS110	New Measurements of Sextupole Field Decay and Snapback Effect on Tevatron Dipole Magnets	dipole, injection, sextupole, LEFT	2640
	G. Velev, P. Bauer, R.H. Carcagno, J. DiMarco, M.J. Lamm, D.F. Orris, P. Schlabach, C. Sylvester, M. Tartaglia, J. Tompkins Fermilab, Batavia, Illinois
	To perform detailed studies of the dynamic effects in superconducting accelerator magnets, a fast continuous harmonics measurement system based on the application of a digital signal processor (DSP) has been built at Fermilab. Using this new system the dynamic effects in the sextupole field, such as the field decay during the dwell at injection and the rapid subsequent "snapback" during the first few seconds of the energy ramp, are evaluated for more than ten Tevatron dipoles from the spares pool. The results confirm the previously observed fast drift in the first several seconds of the sextupole decay and provided additional information on a scaling law for predicting snapback duration. The presented information can be used for an optimization of the Tevatron and for future LHC operations.

WEPLS112	Study of 2-in-1 Large-aperture Nb3Sn IR Quadrupoles for the LHC Luminosity Upgrade	quadrupole, dynamic-aperture, magnet-design, luminosity	2643
	A.V. Zlobin, V. Kashikhin Fermilab, Batavia, Illinois
	After LHC operates for several years at nominal parameters, it will be necessary to upgrade it to higher luminosity. Replacement of the low-beta insertions with higher performance design based on advanced superconducting magnets is one of the most straightforward steps in this direction. An interesting option for a new IR design is a double bore inner triplet with separation dipoles placed in front of the focusing quadrupoles. This approach reduces the number of parasitic collisions by more than a factor of three with respect to the quadrupoles-first option and allows independent field error correction for each beam. Several designs of the 2-in-1 Nb3Sn quadrupole magnets suitable for the LHC IR upgrade have been studied, including magnets with "cold" and "warm" iron yokes based on symmetric or asymmetric coils. This paper describes the design concepts of 2-in-1 large-aperture IR quadrupoles and compares their major performance parameters, including aperture, field gradient, field quality, electromagnetic stresses in the coils, and discuss some technological aspects of magnet fabrication.

WEPLS140	Update and Summary of the Dependability Assessment of the LHC Beam Dumping System	dumping, beam-losses, kicker, CERN	2706
	R. Filippini, J.A. Uythoven CERN, Geneva
	The LHC Beam Dumping System (LBDS) must be able to remove the high intensity beams from the LHC accelerator on demand, at any moment during the operation. As the consequences of a major failure can be very severe, stringent safety requirements were imposed on the design. The final results of an in-depth dependability analysis on the LBDS are summarised, for one year of operation and different operational scenarios. The trade-off between safety and availability is discussed, along with the benefit from built-in features like redundancy, on-line surveillance and post-mortem diagnostics.

WEPLS141	Operational Experience with the LHC Waveguide Mode Reflectometer	quadrupole, dipole, CERN, insertion	2709
	T. Kroyer, P. Borowiec, F. Caspers, Z. Sulek, L.R. Williams CERN, Geneva
	The LHC microwave mode reflectometer (assembly version) reached operational status by the end of 2005. It is now routinely used in the LHC tunnel to take data on the beam-screen of the individual LHC magnets and also groups of magnets with lengths up to 200 meter. The reflectometer operates in the frequency range from about 4GHz to 8 GHz and employs mode selective launchers. Data traces of typically 16000 data points are taken in the frequency domain with subsequent Fourier transformation into the time domain and numerical waveguide mode dispersion compensation. This paper discusses the operational aspects of the system as well as methods for clutter (fake reflection) elimination and procedures for cross-checks in case of a suspected obstacle or other fault.

WEPLS142	The Importance of Layout and Configuration Data for Flexibility during Commissioning and Operation of the LHC Machine Protection Systems	controls, extraction, superconducting-magnet, CERN	2712
	J. Mariethoz, F.B. Bernard, R.H. Harrison, P. Le Roux, M.P. Peryt, M. Zerlauth CERN, Geneva
	Due to the large stored energies in both magnets and particle beams, the LHC requires a large inventory of machine protection systems, as e.g. powering interlock systems, based on a series of distributed industrial controllers for the protection of the more than 10,000 normal and superconducting magnets. Such systems are required to be at the same time fast, reliable and secure but also flexible and configurable to allow for automated commissioning, remote monitoring and optimization during later operation. Based on the generic hardware architecture of the LHC machine protection systems presented at EPAC 2002 and ICALEPS 2003, the use of configuration data for protection systems in view of the required reliability and safety is discussed. To achieve the very high level of reliability, it is required to use a coherent description of the layout of the accelerator components and of the associated machine protection architecture and their logical interconnections. Mechanisms to guarantee coherency of data and repositories and secure configuration of safety critical systems are presented. This paper focuses on the first system being commissioned, the complex magnet powering system.

THPCH018	Resonance Trapping, Halo Formation and Incoherent Emittance Growth due to Electron Cloud	electron, emittance, simulation, resonance	2820
	E. Benedetto, E. Benedetto Politecnico di Torino, Torino G. Franchetti GSI, Darmstadt G. Rumolo, F. Zimmermann CERN, Geneva
	The pinched electron cloud introduces a tune shift along the bunch, which together with synchrotron motion, leads to a periodic crossing of resonances. The resonances are excited by the longitudinal distribution of the electron cloud around the storage ring. We benchmark the PIC code HEADTAIL against a simplified weak-strong tracking code based on an analytical field model, obtaining an excellent agreement. The simplified code is then used for exploring the long term evolution of the beam emittance, and for studying more realistic lattice models. Results are presented for the CERN SPS and the LHC.

THPCH034	Transverse Coupling Impedances From Field Matching in a Smooth Resistive Cylindrical Pipe for Arbitrary Beam Energies	impedance, coupling, SIS, CERN	2853
	A.M. Al-Khateeb, A.M. Al-Khateeb, W.M. Daqa Yarmouk, Irbid O. Boine-Frankenheim, R.W. Hasse, I. Hofmann GSI, Darmstadt
	The transverse coupling impedance is investigated analytically. For an off-axis motion of the beam, the perturbed charge distribution of the beam becomes a function of the azimuthal angle, resulting to first order in the beam displacement in a dipole term which is the source of the transverse impedance. All six components of the electromagnetic field are different from zero and, therefore, both TM and TE modes will be excited in the beam-pipe and coupled to the beam at the inner surface of the resistive wall. Using the dipole source term, a linear combination of TM and TE modes is used to get closed form expressions for the transverse electromagnetic field components excited in the beam-pipe, and a generalized analytic expression for the corresponding transverse coupling impedance. It has been found that the contributions of the TM and the TE modes to the real part of the transverse resistive-wall impedance have similar dependence on the relativistic parameter but with opposite signs, the sum of both always being positive. Some approximate simple formulas for three important regions corresponding to small, intermediate and large frequencies in the ultrarelativistic limit were also obtained analytically.

THPCH047	Maps for Electron Clouds: Application to LHC	electron, simulation, space-charge, CERN	2889
	T. Demma, S. Petracca U. Sannio, Benevento F. Ruggiero, G. Rumolo, F. Zimmermann CERN, Geneva
	Electron Cloud studies performed so far were based on very heavy computer simulations taking into account photoelectron production, secondary electron emission, electron dynamics, and space charge effects providing a very detailed description of the electron cloud evolution. In a recent paper* it has been shown that, for the typical parameters of RHIC, the bunch-to-bunch evolution of the electron cloud density can be represented by a cubic map. Simulations based on this map formalism are orders of magnitude faster than those based on usual codes. In this communication we show that the map formalism is also reliable in the range of typical LHC parameters, and discuss the dependence of the polynomial map coefficients on the physical parameters affecting the electron cloud (SEY, chamber dimensions, bunch spacing, bunch charge, etc.). *U. Iriso and S. Peggs. "Maps for Electron Clouds", Phys. Rev. ST-AB 8, 024403, 2005.

THPCH057	The Fast Vertical Single-bunch Instability after Injection into the CERN Super Proton Synchrotron	impedance, SPS, simulation, emittance	2913
	E. Métral, G. Arduini, T. Bohl, H. Burkhardt, G. Rumolo CERN, Geneva B. Spataro INFN/LNF, Frascati (Roma)
	Since 2003, high-intensity single-bunch proton beams with low longitudinal emittance have been affected by heavy losses after less than one synchrotron period after injection. The effects of the resonance frequency of the responsible impedance, longitudinal emittance and chromaticity on the intensity threshold were already discussed in detail in 2004, comparing analytical predictions with simulation results. In this paper the evolution of the instability between injection and the time of beam loss is our main concern. Measurements are compared with HEADTAIL simulations. A travelling-wave pattern propagating along the bunch, which is the signature of a Beam Break-Up or Transverse Mode Coupling Instability (TMCI), is clearly identified. The oscillating frequency, near ~1 GHz, is in good agreement with the usual broad-band impedance model deduced from beam-based measurements like the head-tail growth rate vs. chromaticity.

THPCH061	Tune Shift Induced by Nonlinear Resistive Wall Wake Field of Flat Collimator	impedance, emittance, SPS, CERN	2925
	F. Zimmermann, G. Arduini, R.W. Assmann, H. Burkhardt, F. Caspers, M. Gasior, O.R. Jones, T. Kroyer, E. Métral, S. Redaelli, G. Robert-Demolaize, F. Roncarolo, G. Rumolo, R.J. Steinhagen, J. Wenninger CERN, Geneva
	We present formulae for the coherent and incoherent tune shifts due to the nonlinear resistive wall wake field for a single beam traveling between two parallel plates. In particular, we demonstrate that the nonlinear terms of the resistive wall wake field become important if the gap between the plates is comparable to the transverse rms beam size. We also compare the theoretically predicted tune shift as a function of gap size with measurements for an LHC prototype graphite collimator in the CERN SPS and with simulations.

THPCH105	Summary of Coupling and Tune Feedback Results during RHIC Run 6, and Possible Implications for LHC Commissioning	coupling, feedback, RHIC, betatron	3044
	P. Cameron, A. Della Penna, L.T. Hoff, Y. Luo, A. Marusic, V. Ptitsyn, C. Schultheiss BNL, Upton, Long Island, New York M. Gasior, O.R. Jones CERN, Geneva C.-Y. Tan Fermilab, Batavia, Illinois
	Efforts to implement tune feedback during the acceleration ramp in RHIC have been hampered by the effect of large betatron coupling, as well as by the large dynamic range required by transition crossing with ion beams. Both problems have been addressed, the first by implementation of continuous measurement of coupling using the phase-locked tune meter, and the second by the development of the direct diode detection analog front end. Performance with these improvements will be evaluated during the first days of RHIC Run 6 beam commissioning. With positive results, the possibility of implementing operational feedback control of tune and coupling during beam commissioning will be considered. After beam commissioning, chromaticity feedback will be explored as a part of the accelerator physics experimental program. We will summarize the results of these investigations, and discuss possible implications of these results for LHC commissioning.

THPCH143	The Fast Extraction Kicker System in SPS LSS6	kicker, SPS, extraction, impedance	3125
	E.H.R. Gaxiola, F. Caspers, L. Ducimetière, P. Faure, T. Kroyer, B. Versolatto, E. Vossenberg CERN, Geneva
	A new fast extraction has been set up in SPS LSS6 to transfer 450 GeV/c protons as well as ions to Ring 1 of the LHC, via the transfer line TI 2. The system includes four travelling wave kicker magnets, recuperated from earlier installations and upgraded to fit the new application. All four magnets are powered in series, energised by a single PFN generator and terminated by a short circuit. The layout and the modifications to the magnets and the high voltage circuit are described along with the impact of design choices on the performance of the system. Results from laboratory tests and first machine experience are reported on approaches to overcome the effects of the beam induced kicker heating observed earlier, including a beam screen in form of metallic stripes printed directly onto the ferrites and the use of ferrite blocks with high Curie temperature. Prospects for further improvements are briefly discussed.

THPCH169	Design, Manufacturing and Integration of LHC Cryostat Components: an Example of a Collaboration between CERN and Industry	CERN, vacuum, cryogenics, controls	3191
	M. Canetti, F.G. Gangini RIAL VACUUM S.p.A, Parma N. Bourcey, T. Colombet, V. Parma, I. Slits, J.-P.G. Tock CERN, Geneva
	The components for the LHC cryostats and interconnections are supplied by the European industry. The manufacturing, assembly and testing of these components in accordance with CERN technical specifications require a close collaboration and dedicated approach from the suppliers. This paper presents the different phases of design, manufacturing, testing and integration of four LHC cryostat components supplied by RIAL Vacuum (Parma, Italy), including 108 insulation vacuum barriers, 482 cold-mass extension tubes, 115 cryostat vacuum vessel jumper elbows and 10800 interconnection sleeves. The Quality Assurance Plan, which the four projects have in common, is outlined. The components are all leak-tight thin stainless steel assemblies (< 10^-8 mbar l/s), most of them operating at cryogenic temperature (2 K), however each having specific requirements. Therefore the peculiarities of each component are presented with respect to manufacturing, assembly and testing. These components are being integrated at CERN into the LHC cryostats and interconnections, which allowed validating the design and production quality. The major improvements and difficulties will be discussed.

THPCH180	Equipment for Tunnel Installation of Main and Insertion LHC Cryo-magnets	acceleration, monitoring, dipole, quadrupole	3218
	K. Artoos, S. Bartolome-Jimenez, O. Capatina, T. Feniet, J.L. Grenard, M. Guinchard, K. Kershaw CERN, Geneva
	The installation of about 1700 superconducting dipoles and quadrupoles in the Large Hadron Collider (LHC) is now well underway. The transport and installation of the LHC cryo-magnets in the LEP tunnels originally designed for smaller, lighter LEP magnets have required development of completely new handling solutions. The severe space constraints combined with the long, heavy loads have meant that solutions had to be very sophisticated. The paper describes the procedure of the installation of the main cryo-magnets in the arc as well as the more specific insertion cryo-magnets. The logistics for the handling and transport are monitored with tri-axial acceleration monitoring devices that are installed on each cryo-magnet to ensure their mechanical and geometric integrity. These dynamic results are commented. The paper includes conclusions and some lessons learned.

THPCH181	Overview of the Large Hadron Collider Cryo-magnets Logistics	LEP, CERN, collider, hadron	3221
	O. Capatina, K. Artoos, R. Bihery, P. Brunero, J.M. Chevalley, L.P. Dauvergne, T. Feniet, K. Foraz, J. Francey, J.L. Grenard, M. Guinchard, C. Hauviller, K. Kershaw, S. Pelletier, S. Prodon, I. Ruehl, J. Uwumarogie, R. V. Valbuena, G. Vellut, S. Weisz CERN, Geneva
	More than 1700 superconducting cryo-magnets have to be installed in the Large Hadron Collider tunnel. The long, heavy and fragile LHC cryo-magnets are difficult to handle and transport in particular in the LEP tunnel environment originally designed for smaller, lighter LEP magnets. An installation rate of more than 20 cryo-magnets per week is needed to cope with the foreseen LHC installation end date. The paper gives an overview of the transport and installation sequence complexity, from the storage area at the surface to the cryo-magnet final position in the tunnel. The success of this task depends on a series of independent factors that have to be considered at the same time. The equipment needed for the transport and tunnel installation of the LHC cryo-magnets is briefly described. The manpower and equipment organisation as well as the challenges of logistics are then detailed. The paper includes conclusions and some of the lessons learned during the first phase of the LHC cryo-magnets installation.

THPCH182	Control of the Geometrical Conformity of the LHC Installation with a Single Laser Source	laser, controls, survey, CERN	3224
	J.-P. Corso, M. Jones, Y. Muttoni CERN, Geneva
	A large and complex accelerator like LHC machine needs to integrate several thousand different components in a relatively limited space. During the installation, those components are installed in successive phases, always aiming to leave the necessary space available for the equipment which will follow. To help ensure the correct conditions for the installation, the survey team uses a laser scanner to measure specific areas and provides this data, merged together in a known reference system, to the integration team who compares the results with the 3D CAD models. This paper describes the tools and software used to rebuild underground zones in the CATIA environment, to check interferences or geometrical non-conformities, as well as the procedures defined to solve the identified problems.

THPCH183	Installation and Quality Assurance of the Interconnections between Cryo-assemblies of the LHC Long Straight Sections	cryogenics, CERN, vacuum, controls	3227
	C. Garion, I. Slits, J.-P.G. Tock CERN, Geneva
	The interconnections between the cryomagnets and cryogenic utilities in the LHC long straight sections constitute the last machine installation activity. They are ensuring continuity of the beam and insulation vacuum systems, cryogenic fluid and electrical circuits and thermal insulation. The assembly is carried out in a constraining tunnel environment with restricted space. Therefore, the assembly sequence has to be well defined, and specific tests have to be performed during the interconnection work to secure the reliability of the system and thus to ensure the global accelerator availability. The LHC has eight long straight insertion zones composed of special cryomagnets involving specific interconnection procedures and QA plans. The aim of this paper is to present the installation and quality assurance procedures implemented for the LHC LSS interconnections. Technologies such as manual and automatic welding and resistive soldering will be described as well as the different quality controls such as visual and radiographic inspection of welds, electrical and leak testing. An evaluation and statistical analysis of the results of the interconnection work will be presented.

THPCH184	Handling and Transport of Oversized Accelerator Components and Physics Detectors	CERN, monitoring, acceleration, site	3230
	S. Prodon, C. Bertone, M. Guinchard, P. Minginette CERN, Geneva
	For cost, planning and organisational reasons, it is often decided to install large pre-built accelerators components and physics detectors. As a result, on surface, exceptional transports are required from the construction to the installation sites. Such heavy transports have been numerous during the LHC installation phase. This paper will describe the different types of transport techniques used to fit the particularities of accelerators and detectors components (weight, height, acceleration, planarity) as well as the measurement techniques for monitoring and the logistical aspects (organisation with the police, obstacles on the roads, etc). As far as oversized equipment is concerned, the lowering into the pit is challenging, as well as the transport in tunnel galleries in a very scare space and without handling means attached to the structure like overhead travelling cranes. From the PS accelerator to the LHC, handling systems have been developed at CERN to fit with these particular working conditions. This paper will expose the operating conditions of the main transport equipments used at CERN in PS, SPS and LHC tunnels.

THPCH185	Planning and Logistics Issues Raised by the Individual System Tests during the Installation of the LHC	cryogenics, instrumentation, vacuum, superconducting-magnet	3233
	S. Weisz, E. Barbero-Soto, K. Foraz, F. Rodriguez-Mateos CERN, Geneva
	The running of individual system tests has to fit within tight constraints of the LHC installation planning and of CERN's accelerator activity in general. For instance, the short circuit tests of the power converters that are performed in situ restrict the possibility to work in neighbouring areas; much in the same way, the cold tests of the cryogenic distribution line involve safety access restrictions that are not compatible with the transport and installation of cryo-magnets or interconnect activities in the sector considered. Still, these individual system tests correspond to milestones that are required to ensure that we can continue with the installation of machine elements. This paper reviews the conditions required to perform the individual system tests and describe how the general LHC installation planning is organised to allocate periods for these tests.

FRXCPA01	Design, Construction, Installation and First Commissioning Results of the LHC Cryogenic System	cryogenics, CERN, controls, collider	3626
	S.D. Claudet CERN, Geneva
	The cryogenic system of the Large Hadron Collider (LHC) will be, upon its completion in 2006, the largest in the world in terms of refrigeration capacity with 140 kW at 4.5 K, distributed superfluid helium with 25 km of superconducting magnets below 2 K and cryogen inventory with 100 tons of Helium. The challenges involved in the design, construction and installation, as well as the first commissioning results will be addressed in this talk. Particular mention will be made of the problems encountered and how they were or are being solved. Perspectives for LHC will be presented. General considerations for future large cryogenic systems will be briefly proposed.
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