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CERN

    
Paper Title Other Keywords Page
MOPCH081 FLAIR: a Facility for Low-energy Antiproton and Ion Research antiproton, ion, emittance, storage-ring 220
 
  • C.P. Welsch, C.P. Welsch
    CERN, Geneva
  • H. Danared
    MSL, Stockholm
  To exploit the unique possibilities that will become available at the Facility for Antiproton and Ion Research (FAIR), a collaboration of about 50 institutes from 15 countries was formed to efficiently enable an innovative research program towards low-energy antimatter-physics. In the Facility for Low-energy Antiproton and Ion Research (FLAIR) antiprotons and heavy ions are slowed down from 30 MeV to energies as low as 20 keV by a magnetic and an electrostatic storage ring. In this contribution, the facility and the research program covered are described with an emphasis on the accelerator chain and the expected particle numbers. An overview of the novel beam handling, cooling and imaging techniques as they will be required across the facility is given.  
 
MOPCH094 Low-intensity Beams for LHC Commissioning from the CERN PS-booster LHC, emittance, injection, 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 LHC, injection, emittance, optics 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.  
 
MOPCH097 CERN Proton Synchrotron Working Point Control Using an Improved Version of the Pole-face-windings and Figure-of-eight Loop Powering power-supply, controls, injection, synchrotron 264
 
  • R.R. Steerenberg, J.-P. Burnet, M. Giovannozzi, O. Michels, E. Métral, B. Vandorpe
    CERN, Geneva
  The working point of the CERN Proton Synchrotron, which is equipped with combined function magnets, is controlled using pole-face-windings. Each main magnet consists of one focusing and one de-focusing half-unit on which four pole-face-winding plates are mounted containing two separate coils each, called narrow and wide. At present they are connected in series, but can be powered independently. In addition, a winding called the figure-of-eight loop, contours the pole faces and crosses between the two half units, generating opposite fields in each half-unit. The four optical parameters, horizontal and vertical tune and chromaticity, are adjusted by acting on the pole-face-winding currents in both half units and in the figure-of-eight loop, leaving one physical quantity free. The power supply consolidation project opened the opportunity to use five independent power supplies, to adjust the four parameters plus an additional degree of freedom. This paper presents the results of the measurements that have been made in the five-current mode together with the influence of the magnetic nonlinearities, due to the unbalance in the narrow and wide winding currents, on the beam dynamics.  
 
MOPCH098 LHC@FNAL: A Remote Access Center for the LHC at Fermilab LHC, 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.  
 
MOPCH108 Error Study of LINAC 4 linac, simulation, quadrupole, emittance 294
 
  • M.A. Baylac, J.-M. De Conto, E. Froidefond
    LPSC, Grenoble
  • E.Zh. Sargsyan
    CERN, Geneva
  Within the framework of the Joint Research Activity HIPPI (High Intensity Pulsed Proton Injector) of the CARE program, the conception study of the LINAC 4 accelerator which aims to intensify the proton flux available for the CERN injection line is pursued. The linac, operating in pulsed mode at 352 MHz, is designed to accelerate a 65 mA beam of H- ions up to an energy of 160 MeV. The requirements on acceptable beam emittance growth and particle loss are extremely tight. In order to determine the Drift Tube Linac tolerances, we examined the sensitivity of the LINAC 4 DTL to errors on the accelerating field and the focusing quadrupoles. Simulations were performed with the transport code TRACEWIN (CEA-Saclay, France). We will present results on individual sensitivities to a single error as well as the global impact of alignment and RF errors on the beam quality. Similarly, accelerating structures following the DTL in the LINAC4 design (CCDTL, SCL) have been studied.  
 
MOPCH111 A Fast Beam Chopper for the RAL Front End Test Stand emittance, linac, proton, quadrupole 300
 
  • M.A. Clarke-Gayther
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  • G. Bellodi, F. Gerigk
    CERN, Geneva
  The FETS project at RAL will test a fast beam chopper, designed to address the requirements of high power proton drivers for next generation pulsed spallation sources and neutrino factories. A description is given of the novel RAL 'Fast - Slow' chopping scheme, and of candidate optical designs for the 3.0 MeV, 60 mA, H- Medium Energy Beam Transport (MEBT) line.  
 
MOPCH142 Commissioning of the SOLEIL RF Systems SOLEIL, controls, cryogenics, vacuum 384
 
  • P. Marchand, H.D. Dias, M.D. Diop, M.E. El Ajjouri, J.L. Labelle, R.L. Lopes, M. Louvet, C.M. Monnot, J. Polian, F. Ribeiro, T. Ruan, R.S. Sreedharan, K. Tavakoli, C. Thomas-Madec
    SOLEIL, Gif-sur-Yvette
  • P. Bosland, P. Bredy
    CEA, Gif-sur-Yvette
  The 352 MHz RF accelerating systems for the SOLEIL Booster (BO) and Storage Ring (SR) are being commissioned. In the BO a 5-cell copper cavity of the CERN-LEP type is powered with a 35kW solid state amplifier. In the SR the required RF accelerating voltage (up to 4.4MV) will be provided by two cryomodules, each containing a pair of superconducting cavities, specifically designed for SOLEIL. The parasitic impedances of the high order modes are strongly attenuated by means of four coaxial couplers, located on the tube connecting the two cavities. The first cryomodule is already installed in the SR tunnel, while the second one is being constructed by ACCEL (Germany). These cryomodules are supplied in liquid helium from a single 350W liquefier and each cavity is powered with a 190kW solid state amplifier. The RF system commissioning and first operation results are reported.  
 
MOPCH191 Copper Heat Exchanger for the External Auxiliary Bus-bars Routing Line in the LHC Insertion Regions LHC, 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.  
 
MOPCH195 The LiCAS-RTRS – A Survey System for the ILC survey, laser, simulation, vacuum 520
 
  • A. Reichold, C. Perry
    OXFORDphysics, Oxford, Oxon
  • M. Dawson, J. Green, Y. Han, M. Jones, G. Moss, B. Ottewell, R. Wastie
    JAI, Oxford
  • G. Grzelak
    Warsaw University, Warsaw
  • D. Kaemtner, J. Prenting, E. Saemann, M. Schloesser
    DESY, Hamburg
  The ILC requires an unprecedented accuracy and speed for the survey and alignment of its components. The Rapid Tunnel Reference Surveyor (RTRS) is a self-propelled train intended to automatically survey a reference network in the ILC tunnels with a design accuracy of 200 microns over distances of 600 m. A prototype RTRS has been built by the LiCAS collaboration. It will shortly commence operation at DESY. The operation principle of the RTRS will be explained. The status of the project's hardware, software and calibrations as well as the principles and performance of the underlying measurement techniques will be described.  
 
MOPLS001 Large Scale Beam-beam Simulations for the CERN LHC using Distributed Computing LHC, 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, LHC, insertion, shielding 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.  
 
MOPLS005 A Staged Approach to LHC Commissioning LHC, instrumentation, controls, 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.  
 
MOPLS015 Quality Control Techniques Applied to the Large Scale Production of Superconducting Dipole Magnets for LHC LHC, 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.  
 
MOPLS017 A Low Gradient Triplet Quadrupole Layout Compatible with NbTi Magnet Technology and Betastar=0.25m LHC, sextupole, luminosity, quadrupole 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 LHC, luminosity, radiation, 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.  
 
MOPLS069 Development of a Superconducting Helical Undulator for the ILC Positron Source undulator, positron, electron, linear-collider 706
 
  • Y. Ivanyushenkov, E. Baynham, T.W. Bradshaw, A.J. Brummitt, F.S. Carr, J. Rochford
    CCLRC/RAL, Chilton, Didcot, Oxon
  • I.R. Bailey, D.P. Barber, J.A. Clarke, J.B. Dainton, O.B. Malyshev, D.J. Scott, B.J.A. Shepherd
    Cockcroft Institute, Warrington, Cheshire
  • P. Cooke, L.I. Malysheva
    Liverpool University, Science Faculty, Liverpool
  • G.A. Moortgat-Pick
    CERN, Geneva
  An undulator positron source has been recently selected by the International Linear Collider (ILC) community as a baseline. For the ILC a helical undulator capable of producing 10 MeV photons and with a period as close as possible to 10 mm is required. The HeliCal collaboration in the UK is looking at the merits of both permanent magnet and superconducting technologies for the design of a helical undulator. For the superconducting option, several prototypes have been built and tested. This paper details the design, construction and test results of the first superconducting prototypes.  
 
MOPLS070 Numerical Calculations of Collimator Insertions simulation, impedance, insertion, SLAC 709
 
  • C.D. Beard
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • J.D.A. Smith
    Cockcroft Institute, Warrington, Cheshire
  A series of collimator spoilers have been designed and manufactured for testing in the ESA wakefield tests. The purpose of the tests is a benchmarking exercise to assist with the understanding into the causes of wakefields due to spoiler profile and materials. Simulations of the spoiler designs have been used to understand the likely effects that would be observed with the beam tests. Simulations of these collimator insertions have been carried out in MAFIA and GDFIDL, and a comparison of the results completed. The wake potential has been measured, and the corresponding loss factor and kick factors have been calculated. The results from the simulations are discussed in this report.  
 
MOPLS093 Commissioning Status of the CTF3 Delay Loop CLIC, CTF3, linac, wiggler 771
 
  • R. Corsini, S. Doebert, F. Tecker, P. Urschütz
    CERN, Geneva
  • D. Alesini, C. Biscari, B. Buonomo, A. Ghigo, F. Marcellini, B. Preger, M. Serio, A. Stella
    INFN/LNF, Frascati (Roma)
  The CLIC Test Facility CTF3, built at CERN by an international collaboration, aims at demonstrating the feasibility of the CLIC scheme by 2010. In particular, one of the main goals is to study the generation of high-current electron pulses by interleaving bunch trains in delay lines and rings using transverse RF deflectors. This will be done in the 42 m long delay loop, built under the responsibility of INFN/LNF, and in the 84 m long combiner ring that will be installed in 2006. The delay loop installation was completed, and its commissioning started at the end of 2005. In this paper the commissioning results are presented, including the first tests of beam recombination.  
 
MOPLS095 Investigations of DC Breakdown Fields cathode, vacuum, CLIC, ion 777
 
  • T. Ramsvik, S. Calatroni, A. Reginelli, M. Taborelli
    CERN, Geneva
  The need for high accelerating gradients for the future 30 GHz multi-TeV e+e- Compact Linear Collider (CLIC) at CERN has triggered a comprehensive study of DC breakdown fields of metals in UHV. The experimental setup is based on a capacitor discharge across a gap junction. The simple design and fully automated computer control enable breakdown fields and dark current of numerous materials to be measured. The study shows that Mo, W and Ti reach high breakdown fields, and are thus good candidates for the iris material of CLIC structures. For untreated Mo the breakdown field is higher than Cu but the conditioning speed is slower. Ti, on the other hand, shows acceptable conditioning speeds, but material erosion makes this solution problematic. Feasible solutions to increase the spark conditioning speed for the case of Mo are presented together with attempts to prevent Ti erosion. For some of the materials studied a significant reduction in the saturated breakdown field was observed upon gas exposure during intensive spark conditioning. As an example, a 50% decrease of the breakdown field of Mo is recorded when spark conditioning is carried out in an environment of 10-5 mbar air.  
 
MOPLS101 Beam Dynamics and First Operation of the Sub-harmonic Bunching System in the CTF3 Injector CTF3, simulation, bunching, linac 795
 
  • P. Urschütz, H.-H. Braun, G. Carron, R. Corsini, S. Doebert, T. Lefevre, G. McMonagle, J. Mourier, J.P.H. Sladen, F. Tecker, L. Thorndahl, C.P. Welsch
    CERN, Geneva
  The CLIC Test Facility CTF3, built at CERN by an international collaboration, aims at demonstrating the feasibility of the CLIC scheme by 2010. The CTF3 drive beam generation scheme relies on the use of a fast phase switch of a sub-harmonic bunching system in order to phase-code the bunches. The amount of charge in unwanted satellite bunches is an important quantity, which must be minimized. Beam dynamics simulations have been used to study the problem, showing the limitation of the present CTF3 design and the gain of potential upgrades. In this paper the results are discussed and compared with beam measurements taken during the first operation of the system.  
 
MOPLS128 Status of the Fatigue Studies of the CLIC Accelerating Structures CLIC, laser, target, radio-frequency 858
 
  • S.T. Heikkinen, S.T. Heikkinen
    HUT, Espoo
  • S. Calatroni, H. Neupert, W. Wuensch
    CERN, Geneva
  The need for high accelerating gradients for the future Compact Linear Collider imposes considerable constraints on the materials of the accelerating structures. The surfaces exposed to high pulsed RF currents are subjected to cyclic thermal stresses possibly resulting in surface break up by fatigue. Since no fatigue data exists in the literature up to very large numbers of cycles, a comprehensive study has been initiated. Low cycle fatigue data (up to 108 cycles) has been collected by means of a pulsed laser surface heating apparatus. The surface damage has been characterized by SEM observations and roughness measurements. High cycle fatigue data (up to 1011 cycles) at various stress ratios have been collected in high frequency bulk fatigue tests using an ultrasonic apparatus. It is found that the appearance of surface fatigue damage in the laser experiments, and of fatigue cracks in the bulk specimen, happen at similar stress levels for similar numbers of cycles. This allows the two experimental techniques to be connected and to predict the surface damage at a high number of cycles. Up-to-date fatigue data for selected high conductivity, high strength Cu alloys are presented.  
 
MOPLS129 Integration of the PHIN RF Gun into the CLIC Test Facility emittance, CTF3, gun, bunching 861
 
  • S. Doebert
    CERN, Geneva
  CERN is a collaborator within the European PHIN project, a joint research activity for Photo injectors within the CARE program. The scope of this project is to build an RF Gun equipped with high quantum efficiency Cs2Te cathodes and a laser to produce the nominal beam for the CLIC Test Facility (CTF3). The nominal beam for CTF3 has an average current of 3.5 A, 1.5 GHz bunch repetition frequency and a pulse length of 1.5 us (2310 bunches) with quite tight stability requirements. In addition a phase shift of 90 deg is needed after each train of 140 ns for the special CLIC combination scheme. This RF Gun will be tested at CERN in fall 2006 and should be integrated as a new injector into the CTF3 linac, replacing the existing injector consisting of a thermionic gun and a subharmonic bunching system. The paper studies the optimal integration into the machine trying to optimize transverse and longitudinal phase space of the beam while respecting the numerous constraints of the existing accelerator. The presented scheme uses emittance compensation and velocity bunching to fulfill the requirements.  
 
TUPCH013 Numerical Calculations of Position Sensitivity for Linear-cut Beam Position Monitors simulation, pick-up, vacuum, coupling 1022
 
  • P. Kowina, A.A. Galatis, W. Kaufmann, J. Schoelles
    GSI, Darmstadt
  In this contribution the results of simulations performed for different geometries of linear-cut Beam Position Monitors (BPMs) are compared for two design types: i)based on metal electrodes and ii)using a metal coated ceramics. The advantage of the ceramic solution is a compact construction allowing easy positioning. Contrary, the construction based on the metal electrodes benefits from its simplicity. The main goals in optimization are the sensitivity and linearity of the position determination. High position sensitivity can be achieved by the reduction of the plate-to-plate cross talks caused by coupling capacities. For instance, the insertion of an additional guard ring into the gap between the active plates leads to an increase of the sensitivity by about 30%. This insertion is necessary in case of ceramic solution: The large ceramics permeability enlarges the coupling capacity by about a factor of four. The careful geometrical arrangement allows to avoid resonances in the interesting frequency range i.e. from 0.2 to 200MHz. The displayed simulations are performed using CST Microwave Studio. The investigated BPMs will be used in the FAIR facility presently under design at GSI.  
 
TUPCH071 Testing the Silicon Photomultiplier for Ionization Profile Monitor photon, IPM, synchrotron, MCP 1172
 
  • S.V. Barabin, D.A. Liakin, A.Y. Orlov
    ITEP, Moscow
  • P. Forck, T. Giacomini
    GSI, Darmstadt
  A new kind of photonic device is proposed to be used in the fast operating mode of the ionization profile monitor. A silicon photomultiplier device combines the advantages of photomultipliers and solid-state photo detectors. It provides high sensitivity, wide optical spectrum response, high bandwidth and absence of 1/f noise component. Those parameters are critical in the IPM with fast readout feature, which is developing in GSI in collaboration with ITEP, COOSY, MSU and CRYRING laboratories. Very first investigations were made to obtain detailed parameters of silicon photomultiplier. A testing layout and resulting performance data are presented in this publication.  
 
TUPCH086 Precision Beam Timing Measurement System for CLIC Synchronization CLIC, CTF3, linac, pick-up 1211
 
  • J.P.H. Sladen, A. Andersson
    CERN, Geneva
  Very precise synchronization between main and drive beams is required in CLIC to avoid excessive luminosity loss due to energy variations. One possibility to accomplish this would be to measure and correct the drive beam phase. The timing reference for the correction could be the beam in the transfer line between the injector complex and the main linac. The timing of both main and drive beams will have to be measured to a precision in the region of 10 fs. The aim is to achieve this by means of a beam measurement at 30 GHz with the signal mixed down to an intermediate frequency (IF) for precise phase detection. The RF and IF electronics are being developed and tests will be carried out in CTF3.  
 
TUPCH087 Beam Diagnostics with Schottky Noise in LEIR ion, pick-up, injection, diagnostics 1214
 
  • J. Tan, G. Tranquille
    CERN, Geneva
  The high density Lead ion beams, needed for LHC, are obtained in the Low Energy Ion Ring (LEIR) at CERN by multi-turn injection followed by electron cooling and stacking. During this injection and stacking phases where the circulating beam is unbunched, diagnostics with Schottky noise are used for probing essential beam parameters, such as tune, momentum spread, emittance and their evolution with time… The hardware facility and first results obtained during the recent commissioning of LEIR are described.  
 
TUPCH143 High Gradient Tests of an 88 MHZ RF Cavity for Muon Cooling factory, linac, simulation, LEFT 1352
 
  • C. Rossi, R. Garoby, F. Gerigk, J. Marques Balula, M. Vretenar
    CERN, Geneva
  The scheme for a Muon Cooling channel developed at CERN in the frame of Neutrino Factory studies foresees the use of 44 and 88 MHz cavities operating at a real-estate gradient as high as 4 MV/m. To assess the feasibility of this scheme, including high-gradient operation at relatively low frequency and the production and handling of high RF peak powers, a test stand was assembled at CERN. It included an 88 MHz resonator reconstructed from a 114 MHz cavity previously used for lepton acceleration in the PS, a 2.5 MW final amplifier made out of an old linac unit improved and down-scaled in frequency, and a PS spare amplifier used as driver stage. After only 160 hours of conditioning the cavity passed the 4 MV/m level, with local peak surface field in the gap exceeding 25 MV/m (2.4 times the Kilpatrick limit). The gradient was limited by the amplifier power, the maximum RF peak output power achieved during the tests being 2.65 MW. This paper presents the results of the tests, including an analysis of field emission from the test cavity, and compares the results with the experience in conditioning ion linac RF cavities at CERN.  
 
TUPCH144 Automatic Conditioning of the CTF3 RF System klystron, vacuum, CTF3, controls 1355
 
  • J.P.H. Sladen, S. Deghaye, S. Livesley, J. Marques Balula, J. Mourier, J.-M. Nonglaton
    CERN, Geneva
  • A. Dubrovsky
    JINR, Dubna, Moscow Region
  The RF system of CTF3 (CLIC Test Facility 3) includes ten 35 MW to 40 MW 3 GHz klystrons and one 20 MW 1.5 GHz klystron. High power RF conditioning of the waveguide network and cavities connected to each klystron can be extremely time consuming. Because of this, a fully automatic conditioning system has been developed within a CERN JINR (Dubna) collaboration. It involves relatively minor hardware additions, most of the work being in application and front-end software. The system has already been used very successfully.  
 
TUPCH172 Status Report on the Performance of NEG-coated Chambers at the ESRF vacuum, ESRF, radiation, beam-losses 1420
 
  • R. Kersevan, M. Hahn, i. Parat
    ESRF, Grenoble
  At the ESRF, the use of NEG-coated narrow gap chambers for insertion device (ID) straight sections has become the standard choice for in-air IDs. A total of 25 chambers have been installed at different times in the ring, with 19 being installed as of Jan 2006, for a total length of 82 m. The vacuum performance has been excellent for all but one of them. It has been found that the now standard "10mm" design, i.e. a 5 m-long, 57x8 mm2 ellipse, is compatible with the multi-bunch operation at 200 mA. Runs at higher currents, performed in preparation of current upgrades, have gone smoothly. During 2005, a 3.5 m-long prototype of a chamber suited for installation in the achromat part of the lattice has been installed in the ring. It was characterized by a much smaller cross-section (30x20 mm2, HxV) as compared to a standard chamber (74x33 mm2, HxV), and by the absence of three lumped pumps, replaced by the NEG-coating. The data taken during a full run have been extremely encouraging, to the point of considering the adoption of a similar design for a future upgrade of the storage ring lattice and vacuum system. A status report will be given, alongside with a discussion of future plans.  
 
TUPCH177 Measurement of the Sorption Characteristics of NEG Coated Pipes: The Transmission Factor Method vacuum, ERL, LHC, 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.  
 
TUPCH196 Digital Design of the LHC Low Level RF: the Tuning System for the Superconducting Cavities controls, LHC, 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.  
 
TUPLS015 Calibration Measurements of the LHC Beam Dumping System Extraction Kicker Magnets LHC, extraction, kicker, dumping 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.  
 
TUPLS016 Characterization of Crystals for Steering of Protons through Channelling in Hadronic Accelerators proton, scattering, lattice, extraction 1523
 
  • V. Guidi, S. Baricordi, M. Fiorini, G. Martinelli, A. Mazzolari, E. Milan
    UNIFE, Ferrara
  • E. Boscolo Marchi, G. Della Mea, R. Milan, S. Todros, A. Vomiero
    INFN/LNL, Legnaro, Padova
  • A. Carnera, D. De Salvador, A. Sambo
    Univ. degli Studi di Padova, Padova
  • Y.A. Chesnokov
    IHEP Protvino, Protvino, Moscow Region
  • Yu.M. Ivanov
    PNPI, Gatchina, Leningrad District
  • W. Scandale
    CERN, Geneva
  Channeling of relativistic particles through a crystal may be useful for many applications in accelerators, and particularly for collimation in hadronic colliders. Efficiency proved to be dependent on the state of the crystal surface and hence on the method used for preparation. We investigated the morphology and structure of the surface of the samples that have been used in accelerators with high efficiency. We found that crystal fabrication by only mechanical methods (dicing, lapping, and others) leads to a superficial damaged layer, which is correlated to performance limitation in accelerators. A planar chemical etching was studied and applied in order to remove the superficial damaged layer. RBS analysis with low-energy protons highlighted better crystal perfection at surface, as a result of the etching. Finally, measurement with 70-GeV protons at IHEP demonstrated a superior performance of the chemically cleaned crystals with respect to conventional samples. A protocol for preparation and characterization of crystal for channelling has been developed, which may be of interest for reliable operation with crystals in accelerators.  
 
TUPLS021 First Observation of Proton Reflection from Bent Crystals proton, scattering, lattice, collimation 1535
 
  • W. Scandale
    CERN, Geneva
  • V.T. Baranov, V.N. Chepegin, Y.A. Chesnokov
    IHEP Protvino, Protvino, Moscow Region
  • Yu.A. Gavrikov, Yu.M. Ivanov, L. P. Lapina, A.A. Petrunin, A.I. Schetkovsky, V. Skorobogatov, A. V. Zhelamkov
    PNPI, Gatchina, Leningrad District
  • V. Guidi
    UNIFE, Ferrara
  • A. Vomiero
    INFN/LNL, Legnaro, Padova
  We recently suggested using short bent crystals as primary collimators in a two-stage cleaning system for hadron colliders, with the aim of providing larger impact parameters in the secondary bulk absorber, through coherent beam-halo deflection*. Tests with crystals a few mm long, performed with 70 GeV proton beams at IEHP in Protvino, showed a channeling efficiency exceeding 85%. We also observed disturbing phenomena such as dechanneling at large impact angle, insufficient bending induced by volume capture inside the crystal, multiple scattering of non-channeled protons and, for the first time, a proton flux reflected by the crystalline planes. Indeed, protons with a tangent path to the curved planes somewhere inside the crystal itself are deflected in the opposite direction with respect to the channeled particles, with an angle almost twice as large as the critical angle. This effect, up to now only predicted by computer simulations**, produces a flux of particles in the wrong direction with respect to the absorber, which may hamper the collimation efficiency if neglected.

*A. Afonin et al. PhysRevLett.87.094802(2001).**A. M. Taratin and S.A.Vorobiev, Phys.Lett. A119(1987)425.

 
 
TUPLS055 First Section of a 352 MHz Prototype Alvarez DTL Tank for the CERN SPL quadrupole, linac, proton, laser 1621
 
  • S.V. Plotnikov, A.P. Durkin, D. Kashinskiy, V.A. Koshelev, T. Kulevoy, S. Minaev, V. Pershin, B.Y. Sharkov, V. Skachkov
    ITEP, Moscow
  • V.F. Basmanov, V.A. Demanov, I.D. Goncharov, E.S. Mikhailov, N.I. Moskvin, S.T. Nazarenko, V.S. Pavlov, V.V. Porkhaev, V.T. Punin, A.V. Telnov, V.N. Yanovsky, N.V. Zavyalov, S.A. Zhelezov
    VNIIEF, Sarov (Nizhnii Gorod)
  In the Linac4/SPL projects at CERN, 352 MHz 30 mA DTL Alvarez accelerating structure will be used to accelerate protons between 3 and 40 MeV. The R&D for the development of a prototype structure for the energy range from 3 to 10 MeV is taking place jointly at ITEP and VNIIEF. The design of this 2.7 m Alvarez tank containing 27 drift tubes is described in this document. Results of calculations of the section parameters are presented. One of the main features of the design is the use of permanent magnets made of SmCo5 alloy as quadrupole focusing lenses (PMQ) inside the drift tubes. Details of the experimental PMQ-equipped drift tube are described.  
 
TUPLS057 Linac4, a New Injector for the CERN PS Booster linac, rfq, SCL, emittance 1624
 
  • R. Garoby, G. Bellodi, F. Gerigk, K. Hanke, A.M. Lombardi, M. Pasini, C. Rossi, E.Zh. Sargsyan, M. Vretenar
    CERN, Geneva
  The first bottle-neck towards higher beam brightness in the LHC injector chain is due to space charge induced tune spread at injection in the CERN PS Booster (PSB). A new injector called Linac4 is proposed to remove this limitation. Using RF cavities at 352 and 704 MHz, it will replace the present 50 MeV proton Linac2, and deliver a 160 MeV, 40 mA H beam. The higher injection energy will reduce space charge effects by a factor of 2, and charge exchange will drastically reduce the beam losses at injection. Operation will be simplified and the beam brightness required for the LHC ultimate luminosity should be obtained at PS ejection. Moreover, for the needs of non-LHC physics experiments like ISOLDE, the number of protons per pulse from the PSB will increase by a significant factor. This new linac constitutes an essential component of any of the envisaged LHC upgrade scenarios, which can also become the low energy part of a future 3.5 GeV, multi-megawatt superconducting linac (SPL). The present design has benefited from the support of the French CEA and IN2P3, of the European Union and of the ISTC (Moscow). The proposed machine and its layout on the CERN site are described.  
 
TUPLS085 Stacking Simulations in the Beta-beam Decay Ring ion, injection, collimation, simulation 1699
 
  • S. Hancock
    CERN, Geneva
  • A. Chancé
    CEA, Gif-sur-Yvette
  The so-called beta-beam concept for accelerator-driven neutrino experiments envisages the production of a pure beam of electron neutrinos (or their antiparticles) through the beta-decay of radioactive ions circulating in a high-energy storage ring. An unprecedented number of ions must be collected in the decay ring and maintained in a few short bunches. Stacking is unavoidable to match the available source rates with this demand. A new stacking method makes use of off-momentum injection into the decay ring to approach the circulating beam without requiring ultra-fast injection elements, rotation in the longitudinal plane to bring the fresh bunches onto the central orbit and asymmetric merging to transport these ions into the centre of the large stack. Simulation results are presented for the complete repetitive stacking process for two candidate ion species of significantly different charge-to-mass ratio.  
 
TUPLS123 Design of the LHC Beam Dump Entrance Window LHC, kicker, vacuum, 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.

 
 
TUPLS127 Permanent Deformation of the LHC Collimator Jaws Induced by Shock Beam Impact: an Analytical and Numerical Interpretation LHC, 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, simulation, LHC 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.  
 
TUPLS135 Technical Infrastructure Monitoring at CERN monitoring, controls, LHC, 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.  
 
WEXPA03 Digital Low Level RF controls, feedback, linac, collider 1847
 
  • M.-E. Angoletta
    CERN, Geneva
  The demand on high stability and precision on the RF voltage for modern accelerators, as well as better diagnostics, maintenance and flexibility is driving the community to develop Digital Low Level RF systems (DLLRF) for the new linear accelerators, but also for synchrotrons. An overview of the state of the art in digital technologies applied to DLLRF systems and an overview of the different designs developed or in development at the different labs will be presented.  
slides icon Transparencies
 
WEYPA03 CLIC Feasibility Study in CTF3 CTF3, CLIC, linac, collider 1862
 
  • A. Ghigo
    INFN/LNF, Frascati (Roma)
  After a reminder of the CLIC scheme towards multi-TeV Linear Collider and of the main challenges of this novel technology, the presentation will focus on the CTF3 test facility presently under construction at CERN to address all key issues in a multi-lateral collaboration. It will present the status of the facility and of the technological developments, especially the high field accelerating structures and the RF power production, the performances already achieved as well as the plans and schedule for the future. It will finally compare the CTF3 results with those foreseen by the theory and the corresponding benchmarking of CLIC simulations.  
slides icon Transparencies
 
WEPCH048 Measurement and Modeling of Magnetic Hysteresis in the LHC Superconducting Correctors LHC, 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.  
 
WEPCH087 Normal Form for Beam Physics in Matrix Representation lattice, controls, coupling 2122
 
  • S.N. Andrianov
    St. Petersburg State University, Applied Mathematics & Control Processes Faculty, St. Petersburg
  • A.N. Chechenin
    FZJ, Jülich
  The modeling of long beam evolution dynamics in nonlinear accelerator structures has raised new interest in the effective methods of nonlinear effects calculation. Moreover, it is preferably to use both analytical tools and numerical methods for evolution modeling. Usually the standard numerical methods and computer codes are based on the concept of symplectic transfer maps, whereas the analytical tool is the theory of normal forms. The method of normal forms can be realized in symbolic and numerical modes easily enough. In this paper, we discuss the normal form theory based on the matrix formalism for Lie algebraic tools. This approach allows using well known methods of matrix algebra. This permits to compute necessary matrices step-by-step up to desired order of approximation. This procedure leads to more simple structure of matrix representation for very complicated structure of this map does not allow using this map for practical computing. Therefore, it is necessary to transform this map in more appropriate form. In another words the new matrix representation for the map is particularly simple and has explicit invariants and symmetries.  
 
WEPCH093 Parameter Scans and Accuracy Estimates of the Dynamic Aperture of the CERN LHC LHC, dynamic-aperture, simulation, 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.  
 
WEPCH095 Models to Study Multi-bunch Coupling through Head-on and Long-range Beam-beam Interactions coupling, damping, LHC, simulation 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.  
 
WEPCH096 Measurement and Correction of the 3rd Order Resonance in the Tevatron sextupole, resonance, coupling, dipole 2140
 
  • F. Schmidt
    CERN, Geneva
  • Y. Alexahin, V.A. Lebedev, D. Still, A. Valishev
    Fermilab, Batavia, Illinois
  At Fermilab Tevatron BPM system has been recently upgraded resulting much better accuracy of beam position measurements and improvements of data acquisition for turn-by-turn measurements. That allows one to record the beam position at each turn for 8000 turns for all BPMs (118 in each plane) with accuracy of about 10-20 μm. In the last decade a harmonic analysis tool has been developed at CERN that allows relating each FFT line derived from the BPM data with a particular non-linear resonance in the machine. In fact, one can even detect the longitudinal position of the sources of these resonances. Experiments have been performed at the Tevatron in which beams have been kicked to various amplitudes to analyze the 3rd order resonance. It was possible to address this rather large resonance to some purposely powered sextupoles. An alternative sextupole scheme allowed the suppression of this resonance by a good factor of 2. Lastly, the experimental data are compared with model calculations.  
 
WEPCH139 WISE: An Adaptative Simulation of the LHC Optics LHC, simulation, 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.  
 
WEPCH141 Accelerator Physics Code Web Repository simulation, electron, space-charge, site 2254
 
  • F. Zimmermann, R. Basset, E. Benedetto, U. Dorda, M. Giovannozzi, Y. Papaphilippou, T. Pieloni, F. Ruggiero, G. Rumolo, F. Schmidt, E. Todesco
    CERN, Geneva
  • D.T. Abell
    Tech-X, Boulder, Colorado
  • R. Bartolini
    Diamond, Oxfordshire
  • O. Boine-Frankenheim, G. Franchetti, I. Hofmann
    GSI, Darmstadt
  • Y. Cai, M.T.F. Pivi
    SLAC, Menlo Park, California
  • Y.H. Chin, K. Ohmi, K. Oide
    KEK, Ibaraki
  • S.M. Cousineau, V.V. Danilov, J.A. Holmes, A.P. Shishlo
    ORNL, Oak Ridge, Tennessee
  • L. Farvacque
    ESRF, Grenoble
  • A. Friedman
    LLNL, Livermore, California
  • M.A. Furman, D.P. Grote, J. Qiang, G.L. Sabbi, P.A. Seidl, J.-L. Vay
    LBNL, Berkeley, California
  • D. Kaltchev
    TRIUMF, Vancouver
  • T.C. Katsouleas
    USC, Los Angeles, California
  • E.-S. Kim
    PAL, Pohang, Kyungbuk
  • S. Machida
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  • J. Payet
    CEA, Gif-sur-Yvette
  • T. Sen
    Fermilab, Batavia, Illinois
  • J. Wei
    BNL, Upton, Long Island, New York
  • B. Zotter
    Honorary CERN Staff Member, Grand-Saconnex
  In the framework of the CARE HHH European Network, we have developed a web-based dynamic accelerator-physics code repository. We describe the design, structure and contents of this web repository, illustrate its usage, and discuss our future plans.  
 
WEPCH148 Computing TRANSPORT/TURTLE Transfer Matrices from MARYLIE/MAD Lie Maps optics, beam-transport, accelerator-theory, LEFT 2272
 
  • G.H. Gillespie
    G.H. Gillespie Associates, Inc., Del Mar, California
  Modern optics codes often utilize a Lie algebraic formulation of single particle dynamics. Lie algebra codes such as MARYLIE and MAD offer a number of advantages that makes them particularly suitable for certain applications, such as the study of higher order optics and for particle tracking. Many of the older more traditional optics codes use a matrix formulation of the equations of motion. Matrix codes such as TRANSPORT and TURTLE continue to find useful applications in many areas where the power of the Lie algebra approach is not necessary. Arguably the majority of practical optics applications can be addressed successfully with either Lie algebra or matrix codes, but it is often a tedious exercise to compare results from the two types of codes in any detail. Differences in the choice of dynamic variables, between Lie algebra and matrix codes, compounds the comparison difficulties already inherent in the different formulations of the equations of motion. This paper summarizes key relationships and methods that permit that direct numerical comparison of results from MARYLIE and MAD with those from TRANSPORT and TURTLE.  
 
WEPCH150 The Accelerator Markup Language and the Universal Accelerator Parser lattice, quadrupole, multipole, collider 2278
 
  • D. Sagan, M. Forster
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • D.A. Bates, A. Wolski
    LBNL, Berkeley, California
  • T. Larrieu, Y. Roblin
    Jefferson Lab, Newport News, Virginia
  • T.A. Pelaia
    ORNL, Oak Ridge, Tennessee
  • S. Reiche
    UCLA, Los Angeles, California
  • F. Schmidt
    CERN, Geneva
  • P. Tenenbaum, M. Woodley
    SLAC, Menlo Park, California
  • N.J. Walker
    DESY, Hamburg
  A major obstacle to collaboration on accelerator projects has been the sharing of lattice description files between modeling codes. To address this problem, a lattice description format called Accelerator Markup Language (AML) has been created. AML is based upon the standard eXtensible Markup Language (XML) format; this provides the flexibility for AML to be easily extended to satisfy changing requirements. In conjunction with AML, a software library, called the Universal Accelerator Parser (UAP), is being developed to speed the integration of AML into any program. The UAP is structured to make it relatively straightforward (by giving appropriate specifications) to read and write lattice files in any format. This will allow programs that use the UAP code to read a variety of different file formats. Additionally this will greatly simplify conversion of files from one format to another. Currently, besides AML, the UAP supports the MAD lattice format.  
 
WEPCH152 Comment on Healy's Symplectification Algorithm BNL, AGS, dipole 2281
 
  • W.W. MacKay
    BNL, Upton, Long Island, New York
  For long-term tracking, it is important to have symplectic maps for the various electromagnetic elements in an accelerator ring. While many standard elements are handled well by modern tracking programs, new magnet configurations (e.g., a helical dipole with a superimposed solenoid) are being used in real accelerators. Transport matrices and higher terms may be calculated by numerical integration through model-generated or measured field maps. The resulting matrices are most likely not quite symplectic due to numerical errors in the integrators as well as the field maps. In his thesis*, Healy presented a simple algorithm to symplectify a matrix. This paper presents a discussion of limitations of this method.

*L. M. Healy, "Lie Algebraic Methods for Treating Parameter Errors in Particle Accelerators", Doctoral Thesis. University of Maryland, unpublished (1986).

 
 
WEPCH156 CERN Safety Alarms Monitoring System (CSAM) monitoring, site, controls, LHC 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.  
 
WEPCH162 Magnet Simulations for Medical FFAG simulation, dipole, magnet-design 2310
 
  • E. Froidefond
    LPSC, Grenoble
  • B. Autin
    CERN, Geneva
  Studies have been undertaken concerning magnet design in the frame of the RACCAM FFAG project (this conference). This contribution reports on the objectives of the project in that matter, on the working methods and calculation tools developments, magnetic field modeling and simulations, and on the present status of this work.  
 
WEPLS006 Requirements for Accelerator-based Neutrino Facilities factory, alignment, monitoring, LEFT 2406
 
  • A.P. Blondel
    DPNC, Genève
  Classification: 1-A18, 3-A09, 4-A15, 6-T03 (non exhaustive). The study of neutrino oscillations offers promises of great discoveries including leptonic CP violation. The experimental programs that are under discussion pose considerable challenges to accelerator builders. Extremely high intensities are needed for classical on- and off-axis pion decay beams; novel ideas such as beta-beams and muon decay beams have been invented and are being studied. The experiments to be performed require outstanding predictability and monitoring of the neutrino flux. The challenges will be reviewed and a list of requirements will be proposed.  
 
WEPLS059 The PHIN Photoinjector for the CTF3 Drive Beam gun, laser, CTF3, vacuum 2517
 
  • R. Losito, H.-H. Braun, N. Champault, E. Chevallay, V. Fedosseev, A. Kumar, A.M. Masi, G. Suberlucq
    CERN, Geneva
  • G. Bienvenu, B.M. Mercier, C.P. Prevost, R. Roux
    LAL, Orsay
  • M. Divall, G.J. Hirst, G. Kurdi, W. E. Martin, I. O. Musgrave, I. N. Ross, E. L. Springate
    CCLRC/RAL, Chilton, Didcot, Oxon
  A new photoinjector for the CTF3 drive beam has been designed and is now being constructed by a collaboration among LAL, CCLRC and CERN within PHIN, the second Joint Research Activity of CARE. The photoinjector will provide a train of 2332 pulses at 1.5 GHz with a complex timing structure (sub-trains of 212 pulses spaced from one another by 333 ps or 999 ps) to allow the frequency multiplication scheme, which is one of the features of CLIC, to be tested in CTF3. Each pulse of 2.33 nC will be emitted by a Cs2Te photocathode deposited by a co-evaporation process to allow high quantum efficiency in operation (>3% for a minimum of 40 h). The 3 GHz, 2 1/2 cell RF gun has a 2 port coupler to minimize emittance growth due to asymmetric fields, racetrack profile of the irises and two solenoids to keep the emittance at the output below 20 pi.mm.mrad. The laser has to survive very high average powers both within the pulse train (15 kW) and overall (200 W before pulse slicing). Challenging targets are also for amplitude stability (<0.25% rms) and time jitter from pulse to pulse (<1ps rms). An offline test in a dedicated line is foreseen at CERN in 2007.  
 
WEPLS073 A Super Strong Adjustable Permanent Magnet Quadrupole for the Final Focus in a Linear Collider permanent-magnet, quadrupole, linear-collider, collider 2550
 
  • Y. Iwashita, T. Mihara
    Kyoto ICR, Uji, Kyoto
  • M. Kumada
    NIRS, Chiba-shi
  • C.M. Spencer
    SLAC, Menlo Park, California
  An adjustable permanent magnet quadrupole has been fabricated to demonstrate its feasibility for use in the final focus of a linear collider. The supposed requirements for such a final focus lens are the tight stabilities of its integrated field gradient and magnetic center, plus it must have adjustable strength. The high temperature coefficient of the permanent magnet material NEOMAX is compensated by use of the MS-1 Fe-Ni alloy. The magnet has two concentric rings of NEOMAX. The replacement of the inner ring with a smaller diameter one is planned in order to reach the highest gradient with the current configuration of the quadrupole system; the system has to be scaled down in size to fit in a real linear collider final focus system. A precise magnetic field measurement system is also under fabrication that will be able to measure the magnetic center to a fraction of a micron.  
 
WEPLS083 Consolidation of the 45-year-old CERN PS Main Magnet System radiation, radioactivity, vacuum, LHC 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.  
 
WEPLS100 Performance of LHC Main Dipoles for Beam Operation dipole, LHC, 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, LHC, 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, LHC, insertion, 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 LHC, quadrupole, 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 LHC, dipole, injection, 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, LHC, 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 LHC, 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, LHC, 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.  
 
WEPLS140 Update and Summary of the Dependability Assessment of the LHC Beam Dumping System LHC, dumping, beam-losses, kicker 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 LHC, quadrupole, dipole, 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 LHC, controls, extraction, superconducting-magnet 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.  
 
THPCH034 Transverse Coupling Impedances From Field Matching in a Smooth Resistive Cylindrical Pipe for Arbitrary Beam Energies impedance, coupling, LHC, SIS 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.  
 
THPCH038 The PANDA Insertion Impedance in High Energy Storage Ring of FAIR impedance, insertion, vacuum, storage-ring 2865
 
  • E. Senicheva, A. Lehrach, D. Prasuhn
    FZJ, Jülich
  The PANDA insertion due to the special shape of the vacuum pipe creates a discontinuity. This was expected to be the main contribution in the impedance of the vacuum chamber. In this paper we present the results of computations dealing with this problem. From many published articles it is known that the reliability of the results depends on many factors and some time they differ from each other significantly. Therefore we have investigated the impedance of the PANDA insertion using different codes and methods, in particular, MAFIA, ABCI and the analytical estimation with the formula Yakoya recognized as a most successful theoretical estimation of the tapers. Besides, PANDA has two symmetrical T-shape insertions, which have been calculated by 3D MAFIA and compared with the results given by the diffraction theory. We have analysed the longitudinal and the transverse impedance.  
 
THPCH047 Maps for Electron Clouds: Application to LHC electron, simulation, LHC, space-charge 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.

 
 
THPCH058 Simulation Study on the Beneficial Effect of Linear Coupling for the Transverse Mode Coupling Instability in the CERN Super Proton Synchrotron coupling, SPS, simulation, impedance 2916
 
  • E. Métral, G. Rumolo
    CERN, Geneva
  The intensity threshold of the transverse mode coupling instability in a flat vertical chamber, as in the CERN Super Proton Synchrotron, is much higher in the horizontal plane than in the vertical one. This asymmetry between the transverse planes led us to the idea that linear coupling from skew quadrupoles could be used to increase the intensity threshold. This technique is already applied, for instance, in the CERN Proton Synchrotron, where a slow head-tail horizontal instability due to the resistive-wall impedance is stabilized by linear coupling only, i.e. with neither octupoles nor feedbacks. This paper presents the results of the study of the effect of linear coupling on the transverse mode coupling instability, using the HEADTAIL simulation code.  
 
THPCH061 Tune Shift Induced by Nonlinear Resistive Wall Wake Field of Flat Collimator impedance, emittance, SPS, LHC 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.  
 
THPCH106 ISAC II RF Controls - Status and Commissioning controls, resonance, target, damping 3047
 
  • M.P. Laverty, S.F. Fang, K. Fong, Q. Zheng
    TRIUMF, Vancouver
  The rf control system for the 20 ISAC II superconducting cavities is a hybrid analogue/digital design which has undergone several iterations in the course of its development. In the current design, the cavity operates in a self-excited feedback loop, while phase locked loops are used to achieve frequency and phase stability. One digital signal processor provides amplitude and phase regulation, while a second is used for mechanical cavity tuning control. The most recent version has been updated to incorporate newer hardware and software technology, as well as to allow for improved manufacturability and diagnostics. Operating firmware and software can be updated remotely, if the need arises and system security permits. This paper describes the RF control system, outlines the status of the system, and details the commissioning experience gained in operating this system with the first four-cavity cryomodule.  
 
THPCH125 Inter-laboratory Synchronization for the CNGS Project SPS, site, extraction, controls 3092
 
  • J. Serrano, P. Alvarez, J. Lewis
    CERN, Geneva
  • D. Autiero
    IN2P3 IPNL, Villeurbanne
  CERN will start sending a neutrino beam to Gran Sasso National Laboratory in Italy in May 2006. This beam will cover a distance of around 730 km through the crust of the earth from an extraction line in CERN's SPS to dedicated detectors in Gran Sasso. This paper describes the technological choices made to fulfill the specification of inter-laboratory synchronization in the region of 100 ns, as well as some preliminary results. The common time standard is UTC as disseminated by the GPS system, and the techniques are similar to those used by national metrology laboratories for the manufacturing of UTC itself. In addition, real-time messages sent through the Internet allow the detectors in Gran Sasso to go into calibration mode when no beam is being sent. Data concerning the delay and determinism of this international network link is also presented.  
 
THPCH169 Design, Manufacturing and Integration of LHC Cryostat Components: an Example of a Collaboration between CERN and Industry vacuum, LHC, 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.  
 
THPCH181 Overview of the Large Hadron Collider Cryo-magnets Logistics LHC, LEP, 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, LHC, controls, survey 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 LHC, cryogenics, 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 LHC, 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.  
 
THPCH196 A Proof-of-Principle Experiment for a High-Power Target System target, proton, BNL, factory 3254
 
  • H.G. Kirk, V. Samulyak, N. Simos, T. Tsang
    BNL, Upton, Long Island, New York
  • J.R.J. Bennett
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  • T.R. Edgecock
    CCLRC/RAL, Chilton, Didcot, Oxon
  • I. Efthymiopoulos, A. Fabich, H. Haseroth, F. Haug, J. Lettry
    CERN, Geneva
  • V.B. Graves, P.T. Spampinato
    ORNL, Oak Ridge, Tennessee
  • K.T. McDonald
    PU, Princeton, New Jersey
  • H.J. Park
    PAL, Pohang, Kyungbuk
  The MERIT experiment, to be run at CERN in 2007, is a proof-of-principle test for a target system that converts a 4-MW proton beam into a high-intensity muon beam for either a neutrino factory complex or a muon collider. The target system is based on a free mercury jet that intercepts an intense proton beam inside a 15-T solenoidal magnetic field.  
 
FRXAPA01 Neutrino Factories and Beta Beams target, factory, proton, acceleration 3616
 
  • M.S. Zisman
    LBNL, Berkeley, California
  The presentation will review the various concepts of Neutrino Factories and Beta Beams and indicate the main challenges in terms of beam performance and technological developments. It will also present the world-wide organization to define and carry out the necessary R&D for component design, beam simulations of facility performance, and benchmarking of key subsystems via actual beam tests. Currently approved subsystem tests include the Muon Ionization Cooling Experiment (MICE), under construction at Rutherford Appleton Laboratory, and the Mercury Intense Target (MERIT) experiment, to be carried out at CERN. The major issues being examined by MICE and MERIT will be described as well as the plans and schedule to address them.  
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FRXCPA01 Design, Construction, Installation and First Commissioning Results of the LHC Cryogenic System cryogenics, LHC, 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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