Paper | Title | Page |
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MOPS013 | Transverse Low Frequency Broad-band Impedance Measurements in the CERN PS | 622 |
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The base-line scenario for the High-Luminosity LHC upgrade foresees an intensity increase delivered by the injectors. With its 53 years, the CERN PS would have to operate beyond the limit of its performances to match the future requirements. Beam instabilities driven by transverse impedance are an important issue for the operation of high intensity beams as for the high-brightness LHC beams. Measurements of transverse tune dependence with beam intensity were performed at injection kinetic energy 1.4~GeV and at LHC beam extraction momentum 26~GeV/c. This allows deducing the low frequency inductive broad-band impedance of the machine. Then an estimation of the real part of the impedance is made by the rise time measurement of a fast transverse instability believed to be a TMCI type. Those are the first step towards a global machine impedance characterization in order to push forward the performances of the accelerator. | ||
MOPS014 | Tune and Space Charge Studies for High-brightness and High-intensity Beams at CERN PS | 625 |
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The current 1.4 GeV CERN PS injection energy limits the maximum intensity required by the future High-Luminosity LHC. The bare-machine large chromaticity combined with the non-linear space charge forces make high-brightness and high-intensity beams crossing betatron resonances along the injection flat bottom, inducing transverse emittance blow-up and beam losses. A scan of the working point plane {Qx,Qy} was done in order to identify beam destructive resonances, in the framework of a possible 2 GeV injection energy upgrade which would reduce the space charge effect on the tune. Experiments were carried out in order to review the maximum space charge tune shift for which no transverse emittance blow-up is observed. The results of measurements and simulations will be presented in this paper. | ||
MOPS015 | 40-80 MHz Muon Front-End for the Neutrino Factory Design Study | 628 |
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Funding: EU FP7 EUROnu WP3. CERN summer student programme. To understand better the neutrino properties, machines able to produce an order of 1021 neutrinos per year have to be built. One of the proposed machine is called a neutrino factory. In this scenario, muons produced by the decay of pions coming from the interaction of a proton beam onto a target are accelerated to energies of several GeV and injected in a storage ring where they will decay in neutrinos. The so-called front-end section of the neutrino factory is conceived to reduce the transverse divergence of the muon beam and to adapt its temporal structure to the acceptance of the downstream accelerators to minimize losses. We present a re-evaluation of the muon front-end scenario which used 40-80 MHz radio-frequency cavities capturing one sign at a time in a single-bunch to bucket mode. The standard software environment of the International Study for the Neutrino Factory (IDS-NF) has been used, for comparison of its performance with the IDS-NF baseline front-end design which operates with higher frequency (330-200 MHz) capturing in a train of alternated sign the muons bunches. |
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MOPS016 | First Observations of Intensity-dependent Effects for Transversally Split Beams | 631 |
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During the commissioning of the CERN PS Multi-Turn Extraction (MTE) tests with different beam intensities were performed. The beam current before transverse splitting was varied and the properties of the five beamlets obtained by crossing the fourth-order horizontal resonance were studied. A clear dependence of the beamlets’ parameters on the total intensity was found, which is a first observation of intensity-dependent effects for such a peculiar beam type. The experimental results are presented and discussed in this paper. | ||
MOPZ008 | Particle Production Simulations for the Neutrino Factory Target | 835 |
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Funding: EU FP7 EUROnu WP3 In the International Design Study for the Neutrino Factory (IDS-NF), a 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 target is situated in a solenoidal field tapering from 20 T down to 1.5 T over a length of several metres, allowing for an optimised capture of pions in order to produce a useful muon beam for the machine. We present results of target particle production calculations using MARS, FLUKA and G4BEAMLINE simulation codes. |
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TUPC135 | Beam Loss Monitors Comparison at the CERN Proton Synchrotron | 1341 |
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CERN is planning the renovation and upgrade of the beam loss detection system for the Proton Synchrotron (PS). Improved performance in speed–to be able to monitor beam loss on a bunch-by-bunch basis–and in long-term stability–to reduce or avoid the need for periodic calibration–are aimed for. To select the most suitable technology, different detectors were benchmarked in the machine with respect to the same beam loss. The characteristics of the different detectors, the results of the measurement campaign and their suitability as future monitors for the PS are presented. | ||
WEPS016 | Update on Comparison of the Particle Production using MARS Simulation Code | 2514 |
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Funding: EU FP7 EUROnu WP3 In the International Design Study for the Neutrino Factory (IDS-NF), a 5-15 GeV (kinetic energy) proton beam impinges a Hg jet target in order to produce pions that will decay into muons. The muons are then captured and transformed into a beam that can be passed to the downstream acceleration system. The target sits in a solenoid field tapering from 20 T down to below 2 T over several meters permitting a optimized capture of the pions that will produce useful muons for the machine. The target and pion capture system have been simulated in MARS simulation code and this work presents an updated comparison of the particles production using the MARS code versions m1507 and m1510. |
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WEPS017 | Plans for the Upgrade of the LHC Injectors | 2517 |
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The LHC Injectors Upgrade (LIU) project has been launched at the end of 2010 to prepare the CERN accelerator complex for reliably providing beam with the challenging characteristics required by the high luminosity LHC until at least 2030. Based on the work already started on Linac4, PS Booster, PS and SPS, the LIU project coordinates studies and implementation, and interfaces with the High Luminosity LHC (HL-LHC) project which looks after the upgrade of the LHC itself, expected by the end of the present decade. The anticipated beam characteristics are described, as well as the status of the studies and the solutions envisaged for improving the injector performances. | ||
WEPS018 | The Proposed CERN Proton-Synchrotron Upgrade Program | 2520 |
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In the framework of the High-Luminosity LHC project, the CERN Proton Synchrotron would require a major upgrade to match the future beam parameters requested as pre-injector of the collider. The different beam dynamics issues, from space-charge limitations to longitudinal instabilities are discussed, as well as the proposed technical solutions to overcome them, covering the increase of the injection energy to RF related improvements. | ||
MOPS009 | Probing Intensity Limits of LHC-type Bunches in the CERN SPS with Nominal Optics | 610 |
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Some of the upgrade scenarios of the high-luminosity LHC require large intensity per bunch from the injector chain. Single bunch beams with intensities of up to 3.5 to 4·1011 p/b and nominal emittances were successfully produced in the PS Complex and delivered to the SPS in 2010. This contribution presents results of studies with this new intense beam in the SPS to probe single bunch intensity limitations with nominal gamma transition. In particular, the vertical Transverse Mode Coupling Instability (TMCI) threshold with low chromaticity was observed at 1.6·1011 p/b for single nominal LHC bunches in the SPS. With increased vertical chromaticity, larger intensities could be injected, stored along the flat bottom and accelerated up to 450 GeV/c. However, significant losses and/or transverse emittance blow up were then observed. Longitudinal and transverse optimization efforts in the PSB, PS and SPS were put in place to minimize this beam degradation and succeeded to obtain single 2.3·1011 p/b LHC type bunches with satisfying parameters at extraction of the SPS. | ||
WEPS019 | Study of a Rapid Cycling Synchrotron to Replace the CERN PS Booster | 2523 |
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CERN’s proton injector chain is undergoing a massive consolidation and upgrade program in order to deliver beams meeting the needs of the LHC Luminosity Upgrade. As an alternative to the upgrade of the existing Proton Synchrotron Booster (PSB), the construction of a Rapid Cycling Synchrotron (RCS) has been studied. This machine would replace the PSB and deliver beams to the LHC as well as to CERN’s rich fixed-target physics program. This paper summarizes the outcome of the feasibility study along with a tentative RCS design. | ||
WEPS022 | Ions for LHC: Performance of the Injector Chain | 2529 |
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The first LHC Pb ion run took place at 1.38 A TeV/c per beam in autumn 2010. After a short period of running-in, the injector chain was able to fill the collider with up to 137 bunches per ring, with an intensity of 108 Pb ions/bunch, about 50% higher than the design value. This yielded a luminosity of 3E25 Hz/cm2, allowing the experiments to accumulate just under 10 inverse microbarn each during the four week run. We review the performance of the individual links of the injector chain, and address the main issues limiting the LHC luminosity, in view of reaching 1026 Hz/cm2 in 2011, and substantially beyond when the LHC energy increases after the long shutdown in 2013-14. | ||
THPS049 | Feasibility Study of a CERN PS Injection at 2 GeV | 3535 |
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In the framework of the potential CERN PS Booster (PSB) energy upgrade, a study was initiated to look into the possibilities and constraints to inject protons into the PS at kinetic energies up to 2 GeV, for LHC type beams and other (high intensity) beams. This paper highlights the identified bottlenecks and potential solutions and addresses the resulting requirements for the hardware in the transfer line and injection region of the PS. In conjunction with the proposed upgrade of the PSB-PS transfer line hardware the optics can be changed for different cycles. Optics solutions optimized for the different requirements of LHC type and other beams are presented. | ||