Paper | Title | Other Keywords | Page |
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MOPR004 | H− Charge Exchange Injection for XiPAF Synchrotron | injection, proton, emittance, dipole | 49 |
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The physics design of the H− charge exchange injection system for Xi’an Proton Application Facility (XiPAF) synchrotron with the missing dipole lattice is discussed. The injection scheme is composed of one septum magnet, three chicane dipoles, two bump magnets and one carbon stripping foil. A 7 μg/cm2 carbon foil is chosen for 7 MeV H− beam for high stripping efficiency and low coulomb scattering effect. The simulation results of the horizontal and vertical phase space painting finished by two bumper magnets and mismatching respectively are presented. | |||
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MOPR005 | RF-Knockout Slow Extraction Design for XiPAF Synchrotron | extraction, septum, resonance, simulation | 52 |
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The physics design of slow extraction for Xi’an Proton Application Facility (XiPAF) synchrotron is discussed. The extraction scheme is composed of two resonant sextupoles, one electrostatic septum (ES) and two septum magnets. The phase space diagram under the Hardt condition at the entrance of ES and the last three turn’s trajectory before extraction are presented. A program is written with C++ to simulate slow extraction process by RF-knockout (RF-KO), the calculation results of dual frequency modulation (FM) and amplitude modulation (AM) are given, and the standard deviation of the fluctuation parameter R1 can be limited 0.2 with optimum parameters under a sampling frequency of about 10 kHz. | |||
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MOPR006 | Design of the 230MeV Proton Accelerator for Xi'an Proton Application Facility | proton, extraction, injection, linac | 55 |
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We report a design of the 230 MeV proton accelera-tor, the Xi’an Proton Application Facility (XiPAF), which will be located in Xi’an city, China. The facility will provide proton beam with the maximum energy of 230 MeV for the research of the single event effect. The facility, composed of a 230 MeV synchrotron, a 7 MeV H− linac injector and two experimental stations, will provide a flux of 105~108 p/cm2/s with the uni-formity of better than 90% on the 10 cm×10 cm sample. | |||
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MOPR007 | Cold and High Power Test of Large Size Magnetic Alloy Core for XiPAF's Synchrotron | impedance, cavity, experiment, proton | 59 |
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A compact magnetic alloy (MA) loaded cavity is under development for XiPAF's synchrotron. The cavity contains 6 large size MA cores, each is independently coupled with solid state power amplifier. Two types of MA core are proposed for the project. We have developed a single core model cavity to verify the impedance model and to test the properties of MA cores under high power state. The high power test results are presented and discussed. | |||
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MOPR009 | Transverse Beam Splitting Made Operational: Recent Progress of the Multi-Turn Extraction at the CERN Proton Synchrotron | extraction, simulation, proton, septum | 65 |
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Following a successful commissioning period, the Multi-Turn Extraction (MTE) at the CERN Proton Synchrotron (PS) has been applied for the fixed-target physics programme at the Super Proton Synchrotron (SPS) since September 2015. This exceptional extraction technique was proposed to replace the long-serving Continuous Transfer (CT) extraction, which has the drawback of inducing high activation in the ring. MTE exploits the principles of non-linear beam dynamics to perform loss-free beam splitting in the horizontal phase space. Over multiple turns, the resulting beamlets are then transferred to the downstream accelerator. The operational deployment of MTE was rendered possible by the full understanding and mitigation of different hardware limitations and by redesigning the extraction trajectories and non-linear optics, which was required due to the installation of a dummy septum to reduce the activation of the magnetic extraction septum. The results of the related experimental and simulation studies, a summary of the 2015 performance analysis, as well as more recent performance improvements are presented in this paper. | |||
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MOPR022 | Longitudinal Particle Tracking Code for a High Intensity Proton Synchrotron | emittance, acceleration, space-charge, beam-loading | 110 |
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We have been developing a longitudinal particle tracking code to design and investigate the beam behavior of the J-PARC proton synchrotrons. The code calculate the longitudinal particle motion with a wake voltage and a space charge effect. The most different point from the other codes is that a synchronous particle motion is calculated from the bending magnetic field pattern. This means the synchronous particle is independent from an acceleration frequency pattern. This feature is useful to check the adiabaticity of the synchrotron. The code also calculates the longitudinal emittance and the filling factor at an rf bucket under the multi-harmonics. We will describe the feature of the code. | |||
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MOPR026 | Space Charge Mitigation With Longitudinally Hollow Bunches | space-charge, resonance, emittance, injection | 130 |
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Funding: CERN, Doctoral Studentship and EPFL, Doctorate Hollow longitudinal phase space distributions have a flat profile and hence reduce the impact of transverse space charge. Dipolar parametric excitation with the phase loop feedback systems provides such hollow distributions under reproducible conditions. We present a procedure to create hollow bunches during the acceleration ramp of CERN's PS Booster machine with minimal changes to the operational cycle. The improvements during the injection plateau of the downstream Proton Synchrotron are assessed in comparison to standard parabolic bunches. |
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MOPR031 | Development of Physics Models of the ISIS Head-Tail Instability | impedance, simulation, space-charge, acceleration | 155 |
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ISIS is the pulsed spallation neutron and muon source at the Rutherford Appleton Laboratory in the UK. Operation centres on a rapid cycling proton synchrotron which accelerates 3·1013 protons per pulse (ppp) from 70 MeV to 800 MeV at 50 Hz, delivering a mean beam power of 0.2 MW. As a high intensity, loss-limited machine, research and development at ISIS is focused on understanding loss mechanisms with a view to improving operational performance and guiding possible upgrade routes. The head-tail instability observed on ISIS is of particular interest as it is currently a main limitation on beam intensity. Good models of impedance are essential for understanding instabilities and to this end, recent beam-based measurements of the effective transverse impedance of the ISIS synchrotron are presented. This paper also presents developments of a new, in-house code to simulate the head-tail instability observed and includes benchmarks against theory and comparisons with experimental results. | |||
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TUAM6X01 | First Analysis of the Space Charge Effects on a Third Order Coupled Resonance | resonance, space-charge, emittance, simulation | 278 |
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The effect of space charge on bunches stored for long term in a nonlinear lattice can be severe for beam survival. This may be the case in projects as SIS100 at GSI or LIU at CERN. In 2012, for the first time, the effect of space charge on a normal third order coupled resonance was investigated at the CERN-PS. The experimental results have highlighted an unprecedented asymmetric beam response: in the vertical plane the beam exhibits a thick halo, while the horizontal profile has only core growth. The quest for explaining these results requires a journey through the 4 dimensional dynamics of the coupled resonance investigating the fixed-lines, and requires a detailed code-experiment benchmarking also including beam profile benchmarking. This proceeding gives a short summary of the experimental results of the 2012 PS measurements, and address an interpretation based on the dynamics the fixed-lines. | |||
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Slides TUAM6X01 [7.183 MB] | ||
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WEAM3X01 | Code Development for Collective Effects | simulation, electron, interface, space-charge | 362 |
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The presentation will cover approaches and strategies of modeling and implementing collective effects in modern simulation codes. We will review some of the general approaches to numerically model collective beam dynamics in circular accelerators. We will then look into modern ways of implementing collective effects with a focus on plainness, modularity and flexibility, using the example of the PyHEADTAIL framework, and highlight some of the advantages and drawbacks emerging from this method. To ameliorate one of the main drawbacks, namely a potential loss of performance compared to the classical fully compiled codes, several options for speed improvements will be mentioned and discussed. Finally some examples and application will be shown together with future plans and perspectives. | |||
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Slides WEAM3X01 [65.643 MB] | ||
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THPM7X01 | Use of RF Quadrupole Structures to Enhance Stability in Accelerator Rings | quadrupole, betatron, octupole, simulation | 505 |
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The beams required for the high luminosity upgrade of the Large Hadron Collider (HL-LHC) at CERN call for efficient mechanisms to suppress transverse collective instabilities. In addition to octupole magnets installed for the purpose of Landau damping, we propose to use radio frequency (rf) quadrupole structures to considerably enhance the aforementioned stabilising effect. By means of the PyHEADTAIL macroparticle tracking code, the stabilising mechanism introduced by an rf quadrupole is studied and discussed. As a specific example, the performance of an rf quadrupole system in presence of magnetic octupoles is demonstrated for HL-LHC. Furthermore, potential performance limitations such as the excitation of synchro-betatron resonances are pointed out. Finally, efforts towards possible measurements with the CERN Super Proton Synchrotron (SPS) are discussed aiming at studying the underlying stabilising mechanisms experimentally. | |||
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Slides THPM7X01 [37.755 MB] | ||
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