Author: Gilardoni, S.S.
Paper Title Page
MOPFI054 Upgrades for the CERN PSB-TO-PS Transfer at 2 GeV 404
  • W. Bartmann, J. Borburgh, J.R.T. Cole, S.S. Gilardoni, B. Goddard, O. Hans, M. Hourican, L. Sermeus, R. Steerenberg
    CERN, Geneva, Switzerland
  • C.H. Yu
    IHEP, Beijing, People's Republic of China
  The CERN PS Booster extraction energy will be upgraded from 1.4 to 2.0 GeV to alleviate the direct space charge tune shift in the PS. The focussing structure of the transfer line will be modified in order to better match the optics between the PSB and the PS. The optics of the PS at injection and, with it, of the transfer line can be adapted to reduce the continuous losses from the already injected and circulating beam bumped towards the septum. Experimental results of the optics optimisation and probing the injection kicker gap will be shown.  
TUPFI018 A Simplified Magnetic Field Tapering and Target Optimisation for the Neutrino Factory Capture System 1370
  • I. Efthymiopoulos, S.S. Gilardoni, O.M. Hansen, G. Prior
    CERN, Geneva, Switzerland
  • O.M. Hansen
    University of Oslo, Oslo, Norway
  • G. Prior
    University of Canterbury, Christchurch, New Zealand
  In the Neutrino Factory, a 4 MW proton beam with a kinetic energy between 5 and 15 GeV interacts with a liquid mercury jet target in order to produce pions that will decay to muons, which in turn decay to neutrinos. The baseline-capturing layout consists of a series of solenoids producing a tapered magnetic field from 20 T, near the target, down to 1.5 T at the entrance of the drift section where the captured pions decay into muons to produce a useful beam for the machine. In our alternative layout the magnetic field is rapidly squeezed from 20 T to 1.5T using only three solenoids. This layout showed to produce similar performance, having the advantage being simpler and could potentially be made more robust to radiation. Here we report on further optimization studies taking into account the complete path and shape fluctuations of the Hg-jet.  
WEPEA013 Electron Cloud Studies for the Upgrade of the CERN PS 2522
  • G. Iadarola
    Naples University Federico II, Science and Technology Pole, Napoli, Italy
  • H. Damerau, S.S. Gilardoni, G. Iadarola, S. Rioja Fuentelsaz, G. Rumolo, G. Sterbini, C. Yin Vallgren
    CERN, Geneva, Switzerland
  • M.T.F. Pivi
    SLAC, Menlo Park, California, USA
  The observation of a significant dynamic pressure rise as well as measurements with dedicated detectors indicate that an electron cloud develops in the CERN PS during the last stages of the RF manipulations for the production of LHC type beams, especially with 25ns bunch spacing. Although presently these beams are not degraded by the interaction with the electron cloud, which develops only during few milliseconds before extraction, the question if this effect could degrade the future high intensity and high brightness beams foreseen by the LHC Injectors Upgrade (LIU) project is still open. Therefore several studies are being carried out employing both simulations and measurements with the electron cloud detectors in the machine. The aim is to develop a reliable electron cloud model of the PS vacuum chambers in order to identify possible future limitations and find suitable countermeasures.  
WEPEA042 The PS Upgrade Programme: Recent Advances 2594
  • S.S. Gilardoni, S. Bart Pedersen, C. Bertone, N. Biancacci, A. Blas, D. Bodart, J. Borburgh, P. Chiggiato, H. Damerau, S. Damjanovic, J.D. Devine, T. Dobers, M. Gourber-Pace, S. Hancock, A. Huschauer, G. Iadarola, L.A. Lopez Hernandez, A. Masi, S. Mataguez, E. Métral, M.M. Paoluzzi, S. Persichelli, S. Pittet, S. Roesler, C. Rossi, G. Rumolo, B. Salvant, R. Steerenberg, G. Sterbini, L. Ventura, J. Vollaire, R. Wasef, C. Yin Vallgren
    CERN, Geneva, Switzerland
  • M. Migliorati
    University of Rome "La Sapienza", Rome, Italy
  The LHC Injectors Upgrade project (LIU) has been initiated to improve the performances of the existing injector complex at CERN to match the future requirements of the HL-LHC. In this framework, the Proton Synchrotron (PS) will undergo fundamental changes for many of its main systems: the injection energy will be increased to reduce space-charge effects, the transverse damper will be improved to cope with transverse instabilities the RF systems will be upgraded to accelerate higher beam intensity and brightness. These hardware improvements are triggered by a series of studies meant to identify the most critical performance bottlenecks, like space charge, impedances, longitudinal and transverse instabilities, as well as electron-cloud. Additionally, alternative production schemes for the LHC-type beams have been proposed and implemented to circumvent some of the present limitations. A summary of the most recent advances of the studies, as well as the proposed hardware improvements is given.  
WEPEA043 Working Point and Resonance Studies at the CERN PS 2597
  • A. Huschauer, M. Benedikt, H. Damerau, P. Freyermuth, S.S. Gilardoni, R. Steerenberg, B. Vandorpe
    CERN, Geneva, Switzerland
  The increase of luminosity demanded by the High Luminosity LHC (HL-LHC) requires an increase of beam intensity, which might result in instabilities appearing at injection energy in the CERN PS. Transverse head-tail instabilities have already been observed on operational LHC beams and a stabilizing mechanism as an alternative to linear coupling is currently being studied. It consists of reducing the mode number of the transverse oscillation by changing linear chromaticity and in succession completely suppressing the instability by a transverse damper system with appropriate bandwidth. Therefore, a chromaticity correction scheme at low energy exploiting the intrinsic possibilities offered by special circuits mounted on top of the main magnet poles, the Pole Face Windings (PFW), has been examined. The presence of destructive betatron resonances, which restrict the choice of the injection working point and the maximum acceptable tune spread, forms an additional limitation for high-brightness and high-intensity beams in the CERN PS. To improve the current working point control scheme, the influence of the P F W on the machine resonances is presented in this paper.  
WEPEA044 RF Manipulations for Higher Brightness LHC-type Beams 2600
  • H. Damerau, A. Findlay, S.S. Gilardoni, S. Hancock
    CERN, Geneva, Switzerland
  In order to increase the transverse brightness of beams for the LHC, ever more complicated RF manipulations have been proposed in the PS machine in order to reduce the intensity demands per PS batch on the upstream PS Booster. Several schemes based on cascades of batch compression, bunch merging, as well as the more routine bunch splitting have been successfully commissioned and higher brightness beams have been delivered to the downstream accelerators for measurement. Despite all this complexity, longitudinal and transverse beam quality are well preserved. In addition, to fully profit from the brightness of all four PS Booster rings, the injection of twice 4 bunches into harmonic 9 buckets in the PS has been made operational as an alternative to the usual double-batch transfer of 4+2 bunches into harmonic 7. This paper summarizes the new beam production schemes, their implementation in the PS low-level RF system and the experimental results.  
WEPEA054 CERN PS Optical Properties Measured with Turn-by-turn Orbit Data 2627
  • C. Hernalsteens, T. Bach, S.S. Gilardoni, M. Giovannozzi, A. Lachaize, G. Sterbini, R. Tomás, R. Wasef
    CERN, Geneva, Switzerland
  The performance of the PS has been constantly increasing over the years both in terms of beam parameters (intensity and brightness) and beam manipulations (transverse and longitudinal splitting). This implies a very good knowledge of the linear and non-linear model of the ring. In this paper we report on a detailed campaign of beam measurements based on turn-by-turn orbit data aimed at measuring the optics in several conditions as well as the resonance driving terms. The goal of this study is to assess whether any specific correction system should be envisaged to achieve the required future performance.  
WEPEA056 Design and Beam Measurements of Modified Fast Extraction Schemes in the CERN PS for Installing a Dummy Septum to Mitigate Ring Irradiation 2633
  • C. Hernalsteens, H. Bartosik, L.N. Drøsdal, S.S. Gilardoni, M. Giovannozzi, A. Lachaize, Y. Papaphilippou, A. Ulsroed
    CERN, Geneva, Switzerland
  The proposed Multi-Turn Extraction (MTE) for the CERN PS allows to reduce the overall extraction losses for high intensity beams. The required longitudinal structure of the proton beam induces unavoidable beam losses at the magnetic extraction septum. The installation of a dummy septum with an appropriate shielding has been proposed to localise losses and to shadow the magnetic septum. Such a device, located in the extraction region, imposes tight constraints on the available beam aperture. Modified extraction schemes have been proposed and in this paper they will be presented and discussed in detail together with the measured performance.  
WEPEA057 Numerical Simulations to Evaluate the Performance of CERN PS Dummy Septum to Reduce Irradiation for the Multi-Turn Extraction 2636
  • C. Hernalsteens, S. Damjanovic, S.S. Gilardoni, M. Giovannozzi
    CERN, Geneva, Switzerland
  The losses created by the proposed Multi-Turn Extraction (MTE) at the CERN PS induces high activation of the magnetic extraction septum due to the de-bunched longitudinal beam structure requested to transfer the beam to the SPS. A mitigation measure is under study aiming at localizing losses in a well-shielded area by shadowing the magnetic extraction septum thanks to septum-like passive device. Such a solution is based on a so-called dummy septum, a blade which absorbs particles during the rise time of the extraction kickers for MTE beams. The efficiency of the scheme is presented in this paper. The quantitative estimate is based on detailed simulations that analyse the beam-matter interaction and provide a determination of the shadowing effect of the dummy septum.  
WEPEA060 Plans for the Upgrade of CERN's Heavy Ion Complex 2645
  • D. Manglunki, M. E. Angoletta, H. Bartosik, A. Blas, D. Bodart, M.A. Bodendorfer, T. Bohl, J. Borburgh, E. Carlier, J.-M. Cravero, H. Damerau, L. Ducimetière, A. Findlay, R. Garoby, S.S. Gilardoni, B. Goddard, S. Hancock, E.B. Holzer, J.M. Jowett, T. Kramer, D. Kuchler, A.M. Lombardi, Y. Papaphilippou, S. Pasinelli, R. Scrivens, G. Tranquille
    CERN, Geneva, Switzerland
  To reach a luminosity higher than 6×1027 Hz/cm2 for Pb-Pb collisions, as expected by the ALICE experiment after its upgrade during the 2nd Long LHC Shutdown (LS2), several upgrades will have to be performed in the CERN accelerator complex, from the source to the LHC itself. This paper first details the present limitations and then describes the strategy for the different machines in the ion injector chain. Both filling schemes and possible hardware upgrades are discussed.  
WEPEA061 The First LHC p-Pb run: Performance of the Heavy Ion Production Complex 2648
  • D. Manglunki, M. E. Angoletta, H. Bartosik, G. Bellodi, A. Blas, M.A. Bodendorfer, T. Bohl, C. Carli, E. Carlier, S. Cettour Cave, K. Cornelis, H. Damerau, A. Findlay, S.S. Gilardoni, S. Hancock, J.M. Jowett, D. Kuchler, M. O'Neil, Y. Papaphilippou, S. Pasinelli, R. Scrivens, G. Tranquille, B. Vandorpe, U. Wehrle, J. Wenninger
    CERN, Geneva, Switzerland
  TThe first LHC proton-ion run took place in January-February 2013; it was the first extension to the collider programme, as this mode was not included in the design report. This paper presents the performance of the heavy ion and proton production complex, and details the issues encountered, in particular the creation of the same bunch pattern in both beams.  
WEPEA070 Space Charge Effects and Limitations in the Cern Proton Synchrotron 2669
  • R. Wasef, G. Arduini, H. Damerau, S.S. Gilardoni, S. Hancock, C. Hernalsteens, A. Huschauer, F. Schmidt
    CERN, Geneva, Switzerland
  • G. Franchetti
    GSI, Darmstadt, Germany
  Space charge produces a large incoherent tune-spread which, in presence of betatronic resonances, could lead to beam losses and emittance growth. In the CERN Proton Synchrotron, at the current injection kinetic energy (1.4 GeV) and even at the future kinetic energy (2 GeV), space charge is one of the main limitations for high brightness beams and especially for the future High-Luminosity LHC beams. Several detailed studies and measurements have been carried out to improve the understanding of space charge limitations to determine the maximum acceptable tune spread and identify the most important resonances causing losses and emittance growth.  
WEPME011 Beam Tests and Plans for the CERN PS Transverse Damper System 2947
  • A. Blas, S.S. Gilardoni, G. Sterbini
    CERN, Geneva, Switzerland
  The CERN Proton Synchrotron (CPS) has been running without any transverse damping equipment since 1998, thanks to the stabilizing effect of the linear coupling applied between horizontal and vertical planes. Lately, the demand for an active damper strongly emerged for two main reasons: to avoid restrictions as imposed on the betatron tune settings by the linear coupling and to cure instabilities appearing with high intensity beams, especially at the extraction energy. Late in 2012, two electronic prototype units, newly developed for the CPS one-turn-feedback, were programmed with a firmware designed to satisfy the transverse feedback (TFB) requirements in both planes. The main achievements were to automatically adapt the loop delay to the particles' time-of-flight variation within a nanosecond precision and to compensate the changing betatron phase advance between pick-up and kicker during the entire accelerating cycle. With the power equipment limited to the modest bandwidth of 23 MHz and 2 x 800 W per plane, encouraging results were obtained such as fast damping of injection oscillations caused by injection errors, reduction of beam losses along the cycle and damping of instabilities at all CPS energies.  
THOBB102 Beam Coupling Impedance Localization Technique Validation and Measurements in the CERN Machines 3106
  • N. Biancacci, G. Arduini, T. Argyropoulos, H. Bartosik, R. Calaga, K. Cornelis, S.S. Gilardoni, N. Mounet, E. Métral, Y. Papaphilippou, S. Persichelli, G. Rumolo, B. Salvant, G. Sterbini, R. Tomás, R. Wasef
    CERN, Geneva, Switzerland
  • M. Migliorati, L. Palumbo
    URLS, Rome, Italy
  The beam coupling impedance could lead to limitations in beam brightness and quality, and therefore it needs accurate quantification and continuous monitoring in order to detect and mitigate high impedance sources. In the CERN machines, for example, kickers and collimators are expected to be the main contributors to the total imaginary part of the transverse impedance. In order to detect the other sources, a beam based measurement was developed: from the variation of betatron phase beating with intensity, it is possible to detect the locations of main impedance sources. In this work we present the application of the method with beam measurements in the CERN PS, SPS and LHC.  
slides icon Slides THOBB102 [7.224 MB]  
THPFI056 Design Study for a Future LAGUNA-LBNO Long-baseline Neutrino Facility at CERN 3418
  • I. Efthymiopoulos, J. Alabau-Gonzalvo, A. Alekou, F. Antoniou, M. Benedikt, M. Calviani, A. Ferrari, R. Garoby, F. Gerigk, S.S. Gilardoni, B. Goddard, A. Kosmicki, C. Lazaridis, J.A. Osborne, Y. Papaphilippou, A.S. Parfenova, E.N. Shaposhnikova, R. Steerenberg, P. Velten, H. Vincke
    CERN, Geneva, Switzerland
  A design study for a long baseline neutrino oscillation experiment (LBNO) with a new conventional neutrino beamline facility (CN2PY) at CERN was initiated in September 2011, supported by EU/FP7 funds. The beam will be aimed at a next generation deep-underground neutrino observatory located at the Pyhasalmi (Finland) mine at a distance of 2300 km. In an initial phase the CN2PY facility will use a 400 GeV beam extracted from SPS up to a maximum power of 750 kW, and in a second phase a 2 MW beam of about 50 GeV produced by a new High-Power Proton Synchrotron accelerator using the LP-SPL as injector also under design. The paper will focus on the design challenges of this MW-class facility and on the optimization studies of the secondary beam elements (target and horns) to produce a neutrino beam spectrum that matches best the experimental requirements for neutrino flavor oscillations and CP-violation tests. The challenges and bottlenecks in the existing CERN accelerator complex to produce the high-intensity beams foreseen for this facility at the initial phase are discussed.  
THPWO077 Status and Plans for the Upgrade of the LHC Injectors 3936
  • R. Garoby, H. Damerau, S.S. Gilardoni, B. Goddard, K. Hanke, A.M. Lombardi, D. Manglunki, M. Meddahi, B. Mikulec, L. Ponce, E.N. Shaposhnikova, R. Steerenberg, M. Vretenar
    CERN, Geneva, Switzerland
  The plans for preparing the LHC injectors to fulfill the needs of the LHC during the next decade have significantly progressed in 2012. Linac4 construction has passed major steps of pre-series fabrication. Hardware developments and beam studies have allowed refining the baseline actions to implement and the beam characteristics achievable at injection into the collider for protons as well as for Lead ions. These achievements are described in this paper, together with the updated project planning matched to the new schedule of the LHC.