SPS

Paper	Title	Other Keywords	Page
MOPLS009	The LHC as a Proton-nucleus Collider	LHC, ion, proton, injection	550
	J.M. Jowett, C. Carli CERN, Geneva
	Following its initial operation as a proton-proton (p-p) and heavy-ion (208Pb82+ - 208Pb82+) collider, the LHC is expected to operate as a p-Pb collider. Later it may collide protons with other lighter nuclei such as 40Ar18+ or 16O8+. We show how the existing proton and lead-ion injector chains may be efficiently operated in tandem to provide these hybrid collisions. The two-in-one magnet design of the LHC main rings imposes different revolution frequencies for the two beams in part of the magnetic cycle. We discuss and evaluate the consequences for beam dynamics and estimate the potential performance of the LHC as a proton-nucleus collider.
TUXPA03	LHC Luminosity and Energy Upgrades	luminosity, LHC, dipole, injection	910
	W. Scandale CERN, Geneva
	LHC upgrade studies are ongoing as part of the EU CARE-HHH network and in the US-LARP collaboration. The aim is a ten-fold increase of the LHC luminosity by about 2014 and a possible upgrade of the injector complex to inject at 1 TeV and, at a later stage, to raise the collider energy. This talk will provide an overview of the beam dynamics and technological challenges associated with the LHC upgrade, including magnet R&D plans, electron cloud and beam-beam limitations, preferred scenarios to maximize the integrated luminosity, and machine experiments on beam-beam compensation or crystal collimation.
	Transparencies
TUZBPA02	Crystal Channelling in Accelerators	extraction, collimation, simulation, proton	945
	V.M. Biryukov IHEP Protvino, Protvino, Moscow Region
	This presentation will begin with a description of the channelling of charged particles through crystals and the use of the channelling effect in accelerators etc. Results from use of crystals for beam deflection and extraction from synchrotrons in Russia, USA and CERN will also be given. Following this the potential advantage of crystals for collimation in high-energy high-intensity machines will be described.
	Transparencies
TUPLS005	Preliminary Study of Using "Pipetron"-type Magnets for a Pre-accelerator for the LHC Collider	LHC, injection, dipole, lattice	1493
	G. De Rijk, L. Rossi CERN, Geneva H. Piekarz Fermilab, Batavia, Illinois
	One of the luminosity limitations of the LHC is the rather low injection energy (0.45 TeV) with respect to the collision energy (7 TeV). The magnetic multipoles in the main dipoles at low field and their dynamic behaviour are considered to limit the achievable bunch intensity and emittance. We report on a preliminary study to increase the injection energy to 1.5 TeV using a two beam pre-accelerator (LHCI) in the LHC tunnel. The LHCI is based on "Pipetron" magnets as originally proposed for the VLHC. The aim of the study is to assess the feasibility and to identify the critical processes or systems that need to be investigated and developed to render such a machine possible.
TUPLS022	Experimental Study of Crystal Channeling at CERN-SPS for Beam-halo Cleaning	proton, LHC, collimation, alignment	1538
	M. Fiorini, P. Dalpiaz, V. Guidi UNIFE, Ferrara G. Ambrosi INFN-PG, Perugia R.W. Assmann, I. Efthymiopoulos, L. Gatignon, W. Scandale CERN, Geneva C. Biino INFN-Torino, Torino Y.A. Chesnokov IHEP Protvino, Protvino, Moscow Region Yu.M. Ivanov PNPI, Gatchina, Leningrad District R. Santacesaria INFN-Roma, Roma A.M. Taratin JINR, Dubna, Moscow Region A. Vomiero INFN/LNL, Legnaro, Padova
	An efficient and robust collimation system is mandatory for any superconducting hadron collider, in particular for the LHC, which will store a beam of unprecedented high intensity and energy. The usage of highly efficient and short primary bent-crystal collimators might be a possibility for reaching nominal and ultimate LHC intensity. Over the last years, groups in Russia (St. Petersburg) and Italy (Ferrara) have developed crystal production methods, which considerably improve the crystal quality. In view of the crystal-collimation experiments at the Tevatron and of the potential improvement compared with the phas·10-1 LHC collimation system, considering the recent progress in crystal technology, we proposed experiments for crystal characterization in the SPS beam lines. Major objectives will be: 1) qualification of the new crystals to be used in the Tevatron; 2) measuring the channeling efficiency of long crystals with 1 mrad and/or 8 mrad bending angle; and 3) comparison of loss patterns around the ring for a crystal with one for amorphous material. In this paper we will report the progress towards the SPS experiment.
TUPLS083	A Low Energy Accumulation Stage for a Beta-beam Facility	ion, electron, injection, accumulation	1693
	A. Källberg, A. Simonsson MSL, Stockholm M. Lindroos CERN, Geneva
	The EU supported EURISOL Design Study encompasses a beta-beam facility for neutrino physics. Intense electron (anti-)neutrino beams are in such a machine generated through the decay of radioactive ions in a high energy storage ring. The two main candidate isotopes for the generation of a neutrino and an anti-neutrino beam are 6He2+ and 18Ne10+. The intensities required are hard to reach, in particular for the neon case. A possible solution to increase the intensity is to use an accumulator ring with an electron cooler. Critical parameters such as cooling times and current limitations due to space charge and tune shifts are presently being optimized. We will in this presentation give an overview of the low energy accumulation stage and review recent work on this option.
TUPLS084	Estimation of Decay Losses and Dynamic Vacuum for the Beta-beam Accelerator Chain	ion, vacuum, acceleration, proton	1696
	M. Benedikt, A. Fabich CERN, Geneva M. Kirk, C. Omet, P.J. Spiller GSI, Darmstadt
	The beta-beam is based on the acceleration and storage of radioactive ions. Due to the large number of ions required and their relatively short lifetime, beam losses are a major concern. This paper estimates the decay losses for the part of the accelerator chain comprising the CERN PS and SPS machines. For illustration purposes, the power deposition in these accelerators is compared to that expected for nominal CNGS proton operation. The beam losses induced vacuum dynamics is simulated and the consequences for machine operation are discussed.
TUPLS122	Implementation of the Proposed Multiturn Extraction at the CERN Proton Synchrotron	extraction, kicker, septum, beam-losses	1789
	M. Giovannozzi CERN, Geneva
	Following the positive results of the three-year measurement campaign at the CERN Proton Synchrotron concerning beam splitting with stable islands in the transverse phase space, the study of a possible implementation of the proposed multi-turn extraction was undertaken. The novel approach would allow a substantial reduction of beam losses, with respect to the present scheme, when delivering the high-intensity proton beams required for the planned CERN Neutrino to Gran Sasso Project. Major modifications to the ring layout are foreseen, such as a new design of the extraction bumps including also the installation of three additional kickers to create a closed-bump over the five turns used to extract the split beam. The ring aperture was reviewed and improvements are proposed to reduce possible beam losses between beam splitting and extraction. The goal consists of implementing the proposed changes by the end of the 2007/2008 PS shutdown and to commission the novel extraction during the 2008 physics run.
TUPLS130	Comparison between Measured and Simulated Beam Loss Patterns in the CERN SPS	simulation, LHC, beam-losses, proton	1810
	S. Redaelli, G. Arduini, R.W. Assmann, G. Robert-Demolaize CERN, Geneva
	A prototype of an LHC collimator has been tested with proton beams at the CERN SPS. The interaction of the circulating proton beam with the carbon collimator jaws generated showers that were lost in the downstream SPS aperture. The measured beam loss patterns are compared in detail with the results of dedicated loss simulations. The simulation package includes (1) a 6D particle tracking through the SPS lattice; (2) the scattering interaction of protons with the collimator jaw material; (3) the time-dependent displacement of the collimator jaws with respect to the beam orbit; (4) a detailed aperture model of the full SPS ring. It is shown that the simulation tools can reliably predict the measured location of losses. This provides an important assessment of the simulation tools in view of the LHC beam loss studies.
WEPCH154	SPS Access System Upgrade	LHC, controls, extraction, injection	2287
	E. Manola-Poggioli, PL. Lienard, T. Pettersson CERN, Geneva
	The present SPS access system is not entirely compatible with the formal requirements of the French Radioprotection Authorities, and a project has been launched to remedy this situation. The upgrade project is split into three phases that will be implemented, in the present planning, in the shutdowns 2006, 2007 and after the first physics run of the LHC, respectively. This paper presents the results of the safety study, the upgrade strategy and the architecture of the upgraded system.
WEPLS081	Modifications to the SPS LSS6 Septa for LHC and the SPS Septa Diluters	extraction, LHC, septum, proton	2565
	J. Borburgh, B. Balhan, B. Goddard, Y. Kadi CERN, Geneva
	The Large Hadron Collider required the modification of the existing extraction channel in the long straight section (LSS) 6 of the CERN Super Proton Synchrotron (SPS), including the suppression of the electrostatic wire septa. The newly set up fast extraction will be used to transfer protons at 450 GeV/c as well as ions via the 2.9 km long transfer line TI 2 to Ring 1 of the LHC. The girder of the existing SPS DC septa was modified to accommodate a new septum protection element. Changes were also applied to the septum diluter in the fast extraction channel in SPS LSS4, leading to the other LHC ring and the CNGS facility. The requirements and the layout of the new LSS6 extraction channel will be described including a discussion of the design and performance of the installed septum diluters.
THPCH057	The Fast Vertical Single-bunch Instability after Injection into the CERN Super Proton Synchrotron	impedance, simulation, emittance, LHC	2913
	E. Métral, G. Arduini, T. Bohl, H. Burkhardt, G. Rumolo CERN, Geneva B. Spataro INFN/LNF, Frascati (Roma)
	Since 2003, high-intensity single-bunch proton beams with low longitudinal emittance have been affected by heavy losses after less than one synchrotron period after injection. The effects of the resonance frequency of the responsible impedance, longitudinal emittance and chromaticity on the intensity threshold were already discussed in detail in 2004, comparing analytical predictions with simulation results. In this paper the evolution of the instability between injection and the time of beam loss is our main concern. Measurements are compared with HEADTAIL simulations. A travelling-wave pattern propagating along the bunch, which is the signature of a Beam Break-Up or Transverse Mode Coupling Instability (TMCI), is clearly identified. The oscillating frequency, near ~1 GHz, is in good agreement with the usual broad-band impedance model deduced from beam-based measurements like the head-tail growth rate vs. chromaticity.
THPCH058	Simulation Study on the Beneficial Effect of Linear Coupling for the Transverse Mode Coupling Instability in the CERN Super Proton Synchrotron	coupling, simulation, impedance, CERN	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.
THPCH060	Simulation Study on the Energy Dependence of the TMCI Threshold in the CERN-SPS	electron, simulation, impedance, space-charge	2922
	G. Rumolo, E. Métral, E.N. Shaposhnikova CERN, Geneva
	This paper concentrates on theoretical studies of Transverse Mode Coupling Instability at the SPS. It shows the expected thresholds based on a HEADTAIL tracking model and on impedance values estimated from previous measurements. First, the effect of space charge is addressed as an important ingredient at the low energies. Subsequently, the change of TMCI threshold possibly induced by a higher injection energy into the SPS (plausible according to the upgrade studies) is investigated and a scaling law with energy is derived.
THPCH061	Tune Shift Induced by Nonlinear Resistive Wall Wake Field of Flat Collimator	impedance, emittance, CERN, 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.
THPCH125	Inter-laboratory Synchronization for the CNGS Project	CERN, 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.
THPCH127	Development of MATLAB-based Data Logging System at Siam Photon Source	controls, storage-ring, synchrotron, photon	3098
	P. Klysubun, C. Netsai NSRC, Nakhon Ratchasima
	New data logging and retrieval systems are currently under development at Siam Photon Source. The systems are written entirely with MATLAB language and utilize two MATLAB toolboxes to handle data communications. The two toolboxes are Open Process Control Toolbox, which is used to carry out communications with Programmable Logic Controllers (PLCs) via Open Process Control Data Access (OPCDA), and Data Acquisition Toolbox, which handles communications with other systems via RS-232 and IEEE-488 interconnections. The interface with the database is handled by the MATLAB Database Toolbox. These MATLAB-based logging and retrieval systems enable accelerator physicists to easily import the logged data to accelerator modeling tools for studies of the accelerator optics. Beamline researchers and users can also write their own retrieval programs to access only the data they need. In this paper we describe the concept, the current status of the systems, and the planned improvements to be carried out in the future.
THPCH143	The Fast Extraction Kicker System in SPS LSS6	kicker, extraction, impedance, LHC	3125
	E.H.R. Gaxiola, F. Caspers, L. Ducimetière, P. Faure, T. Kroyer, B. Versolatto, E. Vossenberg CERN, Geneva
	A new fast extraction has been set up in SPS LSS6 to transfer 450 GeV/c protons as well as ions to Ring 1 of the LHC, via the transfer line TI 2. The system includes four travelling wave kicker magnets, recuperated from earlier installations and upgraded to fit the new application. All four magnets are powered in series, energised by a single PFN generator and terminated by a short circuit. The layout and the modifications to the magnets and the high voltage circuit are described along with the impact of design choices on the performance of the system. Results from laboratory tests and first machine experience are reported on approaches to overcome the effects of the beam induced kicker heating observed earlier, including a beam screen in form of metallic stripes printed directly onto the ferrites and the use of ferrite blocks with high Curie temperature. Prospects for further improvements are briefly discussed.