| Paper | Title | Page |
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| MOPFI050 | Non-local Fast Extraction from the CERN SPS at 100 and 440 GeV | 392 |
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| The Long Straight Section 2 (LSS2) of the CERN SPS is connected with the North Area (NA), to which the beam to date has always been extracted using a resonant extraction technique. For new proposed short- and long-baseline neutrino experiments, a fast single turn extraction to this experimental area is required. As there are no kickers in LSS2, and the integration of any new kickers with the existing electrostatic septum would be problematic, a solution has been developed to fast extract the beam using non-local extraction with other SPS kickers. Two different kicker systems have been used, the injection kicker in LSS1 and the stronger extraction kicker in LSS6 to extract 100 and 440 GeV beam, respectively. For both solutions a large emittance beam was extracted after 5 or 9 full betatron periods. The concept and simulation details are presented with the analysis of the aperture and beam loss considerations and experimental results collected during a series of beam tests. | ||
| MOPFI051 | Beam Transfer Systems for the LAGUNA-LBNO Long Baseline Neutrino Beam from the CERN SPS | 395 |
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| For the Long Baseline neutrino facility under study at CERN (LAGUNA-LBNO) it is initially planned to extract a 400 GeV beam from the second long straight section in the SPS into the existing transfer channel TT20 leading to the North Area experimental zone, to a new target aligned with a far detector in Finland. In a second phase a new High-Power Proton Synchrotron (HPPS) accelerator is proposed, to give a 2 MW beam at about 50 GeV on the same target. In this paper the beam transfer systems required for the project are outlined, including the new sections of transfer line between the SPL, HPPS and SPS, and from the SPS to the target, and also the injection and extraction systems in the long straight section of the HPPS. The feasibility of a 4 GeV H− injection system is discussed. | ||
| MOPFI052 | A New Lead Ion Injection System for the CERN SPS with 50 ns Rise Time | 398 |
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| The LHC High Luminosity upgrade project includes a performance upgrade for heavy ions. One of the present performance limitations is the rise time of the SPS injection kicker system, which imposes a spacing of at least 220 ns between injected bunch trains at the operational rigidity. A reduction of this rise time to 50 ns for lead ions is requested as part of the suite of measures needed to increase the present design performance by a factor three. A new injection system based on a fast pulsed septum and a fast kicker has been proposed to fulfil this rise time requirement, and to meet all the constraints associated with the existing high intensity proton injection in the same region. This paper describes the concept and the required equipment parameters, and explores the implications of such a system for SPS operation. | ||
| MOPFI053 | Upgrades of the SPS, Transfer Line and LHC Injection Protection Devices for the HL-LHC Era | 401 |
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| The challenging High Luminosity LHC (HL-LHC) beam requirements will lead in the future to unprecedented beam parameters along the LHC injector chain. In the SPS accelerator these requests translate into about a factor two higher intensity and brightness than the present design performance. In addition to the challenge of producing and accelerating such beams, these parameters affect the resistance of the existing equipment against beam impact. Most of the protection devices in the SPS ring, its transfer lines and the LHC injection areas will be put under operational constraints which are beyond their design specification. The equipment concerned has been reviewed and their resistance to the HL-LHC beams checked. Theoretical and simulation studies have been performed for the SPS beam scraping system, the protection devices and the dump absorbers of the SPS-to-LHC transfer lines, as well as for the LHC injection protection devices. The first results of these studies are reported, together with the future prospects. | ||
| MOPFI054 | Upgrades for the CERN PSB-TO-PS Transfer at 2 GeV | 404 |
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| 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. | ||
| MOPFI055 | Design Study of a 100 GeV Beam Transfer Line from the SPS for a Short Baseline Neutrino Facility | 407 |
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| A Short Baseline neutrino facility at CERN is presently under study. It is considered to extract a 100 GeV beam from the second long straight section of the SPS into the existing transfer channel TT20, which leads to the North Area experimental zone. A new transfer line would branch off the existing TT20 line around 600 m downstream of the extraction, followed by an S-shaped horizontal bending arc to direct the beam with the correct angle onto the defined target location. This paper describes the optimisation of the line geometry with respect to the switch regions in TT20, the integration into the existing facilities and the potential refurbishment of existing magnets. The optics design is shown, and the requirements for the magnets, power converters and instrumentation hardware are discussed. | ||
| MOPFI057 | Studies for the LHeC Beam Transfer Systems | 410 |
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| The LHeC would allow for collisions between an electron beam from a new accelerator with the existing LHC hadron beam. Two possible configurations were studied: a separate LINAC (LINAC-ring) or a new electron ring superimposed on the LHC (ring-ring). The racetrack LINAC is now considered as the baseline for the LHeC design, with the ring-ring solution a back up. The studies performed for all the considered options are presented in this paper. For the LINAC-ring option the requirements for the post-collision line and the beam dump design have been evaluated in the cases of a 140 GeV and a 60 GeV electron beam. In the ring-ring option studies have been performed of the optics design of the transfer line from the a 10 GeV injector LINAC into the LHeC ring and of the injection system. The internal 60 GeV electron ring dump design has also been considered. | ||
| MOPFI059 | Design and Performance of the Beam Transfer Lines for the HIE-ISOLDE Project | 416 |
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| Beam design and beam optics studies for the HIE-ISOLDE transfer lines have been carried out in MadX, and benchmarked against Trace3D results. Magnet field errors and alignment imperfections leading to deviations from design parameters have been treated explicitly, and the sensitivity of the machine's lattice to different individual error sources was studied. As a result, the tolerances for the various error-contributions have been specified for the different equipment systems. The design choices for the expected magnet field and power supply quality, alignment tolerances, instrument resolution and physical aperture were validated. The methodology and results of the studies are presented. | ||
| MOPFI060 | Beam Transfer to LHC with the Low Gamma-transition SPS Optics | 419 |
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| A new low gamma-transition optics with a lower integer tune, was introduced in the SPS to improve beam stability at high intensity. For transferring the beam to the LHC, the extraction bumps, extraction kickers and transfer lines needed to be adapted to the new optics. In particular, the transfer lines were re-matched and re-commissioned with the new optics. The first operational results are discussed for the SPS extraction, the transfer lines and the LHC injection. A detailed comparison is presented between the old and the new optics of the trajectories, dispersion, losses and other performance aspects. | ||
| MOPWO025 | Optics and Protection of the Injection and Extraction Regions of the CLIC Damping Rings | 939 |
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| The optics design of the injection and extraction regions for the CLIC damping rings is presented. The design defines the parameters for the kicker magnets and septa in these regions and has been optimised to minimise the length of the insertions within the parameter space of the system. Failure modes of the injection and extraction elements are identified and their severity assessed. Protection elements for the injection and extraction regions are optimised based on the conclusions of the failure mode analysis. | ||
| MOPWO032 | SPS Scraping and LHC Transverse Tails | 957 |
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| All high-intensity LHC beams have to be scraped before extraction from the SPS to remove the non-Gaussian transverse tails of the particle distributions. The tail particles would otherwise cause unacceptably high losses during injection or other phases of the LHC cycle. Studies have been carried out to quantify the scraping using injection losses and emittance measurements from wire scanners as diagnostics. Beams scraped in the SPS were scraped again in the LHC with collimators to investigate possible tail repopulation. The results of these studies will be presented in this paper. | ||
| MOPWO033 | Analysis of LHC Transfer Line Trajectory Drifts | 960 |
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| The LHC is filled from the SPS via two 3km long transfer lines. In the first years of LHC operation large trajectory variations were discovered. The sources of bunch-by-bunch and shot-by-shot trajectory variations had been identified and improved by the 2012 LHC run. The origins of the longer term drifts were however still unclear and significant time was spent correcting the trajectories. In the last part of the 2012 run the optics in the SPS was changed to lower transition energy. Trajectory stability and correction frequency will be compared between before and after the optics change in the SPS. The sources of the variations have now been identified and will be discussed in this paper. Remedies for operation after the long shutdown will be proposed. | ||
| MOPWO034 | Energy Deposition Studies for the Upgrade of the LHC Injection Lines | 963 |
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| The LHC Injectors Upgrade (LIU) Project aims at upgrading the systems in the LHC injection chain, to reliably deliver the beams required by the High-Luminosity LHC (HL-LHC). Given the challenging beam intensities and emittances, a review of the existing beam-intercepting devices is on-going, in order to assess heat loads and consequent thermo-mechanical stresses. Moreover, the exposure of downstream elements to induced shower radiation is assessed. The study is intended to spot possible issues and contribute to the definition of viable design and layout solutions. | ||
| MOPWO046 | Simulations and Measurements of Beam Losses on LHC Collimators during Beam Abort Failures | 996 |
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Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404. One of the main purposes of tracking simulations for collimation studies is to produce loss maps along the LHC ring, in order to identify the level of local beam losses during nominal and abnormal operation scenarios. The SixTrack program is the standard tracking tool used at CERN to perform these studies. Recently, it was expanded in order to evaluate the proton load on different collimators in case of fast beam failures. Simulations are compared with beam measurements at 4 TeV. Combined failures are assumed which provide worst-case scenarios of the load on tungsten tertiary collimators. |
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| TUPEA051 | Beam Transfer Line Design for a Plasma Wakefield Acceleration Experiment (AWAKE) at the CERN SPS | 1247 |
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| The world’s first proton driven plasma wakefield acceleration experiment is presently being studied at CERN. The experiment will use a high energy proton beam extracted from the SPS as driver. Two possible locations for installing the AWAKE facility are considered: the West Area and the CNGS long baseline beam-line. The previous transfer line from the SPS to the West Area was completely dismantled in 2000 and it would need to be fully re-designed and re-built. For this option, geometric constraints for radio protection reasons would limit the maximum proton beam energy to 300 GeV. The existing CNGS line could be used by applying only minor changes to the final part of the lattice for the final focusing and the interface between the proton beam and the laser, required for plasma ionisation and bunch-modulation seeding. The beam line design studies performed for the two options are presented. | ||
| TUPEA052 | Design Study for a CERN Short Base-Line Neutrino Facility | 1250 |
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| A design study has been initiated at CERN for the conception and construction of a short base line neutrino facility, using a proton beam from the CERN Super Proton Synchrotron (SPS) that will be transferred to a new secondary beam production facility, which will provide a neutrino beam for experiments and detector R&D. This paper resumes the general layout of the facility together with the main primary and secondary beam parameters and the choices favoured for the neutrino beam production. | ||
| TUPEA053 | Feasibility Study of the AWAKE Facility at CERN | 1253 |
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| Plasma Wakefield acceleration is a rapidly developing field which appears to be a promising candidate technology for future high-energy accelerators. The Proton Driven Plasma Wakefield Acceleration has been proposed as an approach to eventually accelerate an electron beam to the TeV energy range in a single plasma section. To verify this novel technique, a proof-of-principle demonstration experiment, AWAKE, is proposed using 400 GeV proton bunches from the SPS. Detailed studies on the identification of the best site for the installation of the AWAKE facility resulted in proposing the CNGS facility as best location. Design and integration layouts covering the beam line, the experimental area and all interfaces and services will be shown. Among other issues, radiation protection, safety and civil engineering constraints will be raised. | ||
| TUPME032 | Update on Beam Induced RF Heating in the LHC | 1646 |
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| Since June 2011, the rapid increase of the luminosity performance of the LHC has come at the expense of increased temperature and pressure readings on specific near-beam LHC equipment. In some cases, this beam induced heating has caused delays whilie equipment cools down, beam dumps and even degradation of these devices. This contribution gathers the observations of beam induced heating attributable to beam coupling impedance, their current level of understanding and possible actions that are planned to be implemented during the long shutdown in 2013-2014. | ||
| WEPEA053 | Progress with the Upgrade of the SPS for the HL-LHC Era | 2624 |
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| The demanding beam performance requirements of the HL-LHC project translate into a set of requirements and upgrade paths for the LHC injector complex. In this paper the performance requirements for the SPS and the known limitations are reviewed in the light of the 2012 operational experience. The various SPS upgrades in progress and still under consideration are described, in addition to the machine studies and simulations performed in 2012. The expected machine performance reach is estimated on the basis of the present knowledge, and the remaining decisions that still need to be made concerning upgrade options are detailed. | ||
| WEPEA060 | Plans for the Upgrade of CERN's Heavy Ion Complex | 2645 |
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| 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. | ||
| WEPEA064 | SixTrack-Fluka Active Coupling for the Upgrade of the SPS Scrapers | 2657 |
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| The LHC Injectors Upgrade (LIU) Project aims at upgrading the systems in the LHC injection chain, to reliably deliver the beams required by the High-Luminosity LHC (HL-LHC). Essential for the clean injection into the LHC, the SPS scrapers are one of the important systems under revision. In order to take into account of the effect of betatron and longitudinal beam dynamics on energy deposition patterns, and nuclear and Coulomb scattering in the absorbing medium onto loss patterns, the SixTrack and Fluka codes have been coupled, profiting from the best of the refined physical models they respectively embed. The coupling envisages an active exchange of tracked particles between the two codes at each turn, and an on-line aperture check in SixTrack, in order to estimate the local cleaning inefficiency of the system. Knob-like, time-dependent strengths have been implemented in SixTrack, since the designed scraper system foresees the use of a magnetic bump. The study is intended to assess the robustness of the proposed scraper as well as its effectiveness with respect to the desired performance. | ||
| THPEA040 | Design of a Magnetic Bump Tail Scraping System for the CERN SPS | 3228 |
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| The LHC injectors are being upgraded to meet the demanding beam specification required for High Luminosity LHC (HL-LHC) operation. In order to reduce the beam losses which can trigger the sensitive LHC beam loss interlocks during the SPS-to-LHC beam injection process, it is important that the beam tails are properly scraped away in the SPS. The current SPS tail cleaning system relies on a moveable scraper blade, with the positioning of the scraper adjusted over time according to the orbit variations of the SPS. A new robust beam tail cleaning system has been designed which will use a fixed scraper block towards which the beam will be moved by a local magnetic orbit bump. The design proposal is presented, together with the related beam dynamics studies and results from machine studies with beam. | ||
| THPEA041 | Performance Improvements of the SPS Internal Beam Dump for the HL-LHC Beam | 3231 |
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| The SPS internal beam dump has been designed for beam specifications well below the HL-LHC ones, and for modes of operation which may not be adequate for the HL-LHC era. The present system suffers from several limitations in the allowed intensity and energy range, and its vacuum performance affects nearby high-voltage kicker systems. In this report the limitations of the internal beam dump system are reviewed, and the possible improvements compared. Preliminary upgrade proposals are presented, taking into consideration the expected operational HL-LHC parameters. | ||
| THPFI056 | Design Study for a Future LAGUNA-LBNO Long-baseline Neutrino Facility at CERN | 3418 |
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| 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 |
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| 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. | ||
| THPWO080 | Operational Performance of the LHC Proton Beams with the SPS Low Transition Energy Optics | 3945 |
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| An optics in the SPS with lower integer tunes (20 versus 26) was proposed and introduced in machine studies since 2010, as a measure for increasing transverse and longitudinal instability thresholds, especially at low energy, for the LHC proton beams. After two years of machine studies and careful optimisation, the new “Q20” optics became operational in September 2012 and steadily delivered beam to the LHC until the end of the run. This paper reviews the operational performance of the Q20 optics with respect to transverse and longitudinal beam characteristics in the SPS, enabling high brightness beams injected into the LHC. Aspects of longitudinal beam stability, transmission, high-energy orbit control and beam transfer are discussed. | ||
| THPWO081 | Design Options of a High-power Proton Synchrotron for LAGUNA-LBNO | 3948 |
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| Design studies have been initiated at CERN, exploring the prospects of future high-power proton beams for producing neutrinos, within the LAGUNA-LBNO project. These studies include the design of a 2 MW high-power proton synchrotron (HP-PS) using the LP-SPL as injector. This paper resumes the design options under study in order to reach this high power, and their implications regarding layout, magnet technology beam loss control and RF considerations. Optics optimization studies are also presented including beam transfer and collimation considerations. | ||