HB2016 - List of Keywords (emittance)

Paper	Title	Other Keywords	Page
MOAM2P20	The LINAC4 Project	linac, cavity, DTL, injection	1
	A.M. Lombardi CERN, Geneva, Switzerland
	Linac4 is a normal conducting, 160 MeV H⁻ ion accelerator that is being constructed within the scope of the LHC injectors upgrade project. Linac4 will be connected to the Proton Synchrotron Booster (PSB) during the next long LHC shut-down and it will replace the current 50 MeV hadron linac, Linac2. Linac4 is presently being commissioned, with the aim of achieving the final energy at the end of the year. A test of the injection chicane and a reliability run will follow. The beam commissioning, in steps of increasing energy, has been prepared by an extended series of studies and interlaced with phases of installation. In this paper we will detail the beam dynamics challenges and we will report on the commissioning results.
	Slides MOAM2P20 [27.527 MB]
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MOPR004	H⁻ Charge Exchange Injection for XiPAF Synchrotron	injection, proton, synchrotron, dipole	49
	H.J. Yao, X. Guan, G.R. Li, X.W. Wang, Q.Z. Xing, S.X. Zheng TUB, Beijing, People's Republic of China
	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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MOPR016	Mitigation of Numerical Noise for Beam Loss Simulations	simulation, space-charge, ion, proton	90
	F. Kesting IAP, Frankfurt am Main, Germany G. Franchetti GSI, Darmstadt, Germany
	Numerical noise emerges in self-consistent simulations of charged particles, and its mitigation is investigated since the first numerical studies in plasma physics. In accelerator physics, recent studies find an artificial diffusion of the particle beam due to numerical noise in particle-in-cell tracking, which is of particular importance for high intensity machines with a long storage time, as the SIS100 at FAIR or in context of the LIU upgrade at CERN. In beam loss simulations for these projects artificial effects must be distinguished from physical beam loss. Therefore, it is important to relate artificial diffusion to artificial beam loss, and to choose simulation parameters such that physical beam loss is well resolved. As a practical tool, we therefore suggest a scaling law to find optimal simulation parameters for a given maximum percentage of acceptable artificial beam loss.
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MOPR017	Status of the Beam Instrumentation System of CSNS	DTL, neutron, linac, rfq	95
	J.L. Sun, J. Peng, R.Y. Qiu, T. Yang CSNS, Guangdong Province, People's Republic of China W.L. Huang, F. Li, P. Li, M. Meng, J.M. Tian, T.G. Xu, Zh.H. Xu, L. Zeng IHEP, Beijing, People's Republic of China
	The first section DTL commissioning of China Spallation Neutron Source (CSNS) project has been successful finished in January, 2016. The H⁻ beam can be accelerated to 21.6 MeV at peak current 18 mA, achieved the design point. Different elements of the beam instrumentation system have been tested during the commissioning, including BPM, CT, FCT, WS, EM, BLM, and corresponding electronics and control systems. High accuracy phase measurement (precision @ ±1°) system has been started into operation. Beam loss monitor (BLM) for low energy, 3 MeV to 21.6 MeV, has been tested too, and got very positive results. For the LRBT, RCS and RTBT, different type wire scanner, BPM, WCM, CT were designed. The monitors fit for the high-radiation environments were considered. All the physical design work has been finished, and being manufactured. Lab test will be started in June and the LINAC commissioning (beam energy up to 80 MeV) will be started in August.
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MOPR018	XAL Applications Development for CSNS Transport Lines	database, linac, interface, controls	98
	Y. Li, Z.P. Li, W.B. Liu IHEP, Beijing, People's Republic of China J. Peng CSNS, Guangdong Province, People's Republic of China
	XAL is an application programming framework initially developed at the Spallation Neutron Source (SNS). It has been employed as a part of control system via con-nection to EPICS to provide application programs for beam commissioning at the China Spallation Neutron Source (CSNS). Several XAL-based applications have been developed for Beam Transport line at CSNS and successfully applied in the MEBT and DTL-1 beam commissioning. These applications will be discussed in this paper.
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MOPR020	Space Charge Effects of High Intensity Beams at BRing	resonance, simulation, injection, betatron	101
	J. Li, J.C. Yang IMP/CAS, Lanzhou, People's Republic of China
	Funding: Work supported by NSFC (Grant No. 11475235) Space charge effects perform one of the main intensity limitations for low energy synchrotron. Large tune spread and crossing resonance stop-bands can hardly be avoided for intensive heavy ion beam at high intensity. Several subjects like Betatron and structure resonance, and tune spread are discussed. Simulations are carried out for 238U³⁴⁺ focusing on emittance and intensity change during RF capture at the injection energy at the booster ring of the High Intensity heavy ion Accelerator Facility (HIAF). lijie@impcas.ac.cn
	Poster MOPR020 [1.157 MB]
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MOPR021	Overview of the ESSnuSB Accumulator Ring	linac, injection, space-charge, simulation	105
	M. Olvegård, T.J.C. Ekelöf Uppsala University, Uppsala, Sweden E. Benedetto, M. Cieslak-Kowalska, M. Martini, H.O. Schönauer, E.H.M. Wildner CERN, Geneva, Switzerland
	The European Spallation Source (ESS) is a research center based on the world’s most powerful proton driver, 2.0 GeV, 5 MW on target, currently under construction in Lund. With an increased pulse frequency, the ESS linac could deliver additional beam pulses to a neutrino target, thus giving an excellent opportunity to produce a high-performance ESS neutrino Super-Beam (ESSnuSB). The focusing system surrounding the neutrino target requires short proton pulses. An accumulator ring and acceleration of an H⁻ beam in the linac for charge-exchange injection into the accumulator could provide such short pulses. In this paper we present an overview of the work with optimizing the accumulator design and the challenges of injecting and storing 1.10¹⁵ protons per pulse from the linac. In particular, particle tracking simulations with space charge will be described.
	Poster MOPR021 [2.731 MB]
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MOPR022	Longitudinal Particle Tracking Code for a High Intensity Proton Synchrotron	acceleration, space-charge, synchrotron, beam-loading	110
	M. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	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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MOPR023	Interpretation of Wire-Scanner Asymmetric Profiles in a Low-Energy Ring	space-charge, scattering, simulation, booster	115
	M. Cieslak-Kowalska, E. Benedetto CERN, Geneva, Switzerland
	In the CERN PS Booster, wire-scanner profile measurements performed at injection energy are affected by a strong asymmetry. The shape was reproduced with the code pyOrbit, assuming that the effect is due to the beam evolution during the scans, under the influence of space-charge forces and Multiple Coulomb Scattering at the wire itself. Reproducing the transverse profiles during beam evolution allows to use them reliably as input for simulation benchmarking.
	Poster MOPR023 [0.482 MB]
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MOPR025	Space Charge Modules for PyHEADTAIL	GPU, space-charge, simulation, vacuum	124
	A. Oeftiger CERN, Geneva, Switzerland S. Hegglin ETH, Zurich, Switzerland
	Funding: CERN, Doctoral Studentship and EPFL, Doctorate PyHEADTAIL is a 6D tracking tool developed at CERN to simulate collective effects. We present recent developments of the direct space charge suite, which is available for both the CPU and GPU. A new 3D particle-in-cell solver with open boundary conditions has been implemented. For the transverse plane, there is a semi-analytical Bassetti-Erskine model as well as 2D self-consistent particle-in-cell solvers with both open and closed boundary conditions. For the longitudinal plane, PyHEADTAIL offers line density derivative models. Simulations with these models are benchmarked with experiments at the injection plateau of CERN's Super Proton Synchrotron.
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MOPR026	Space Charge Mitigation With Longitudinally Hollow Bunches	space-charge, synchrotron, resonance, injection	130
	A. Oeftiger, S. Hancock, G. Rumolo CERN, Geneva, Switzerland
	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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MOPR028	CERN PS Booster Longitudinal Dynamics Simulations for the Post-LS2 Scenario	space-charge, injection, simulation, impedance	140
	D. Quartullo, S.C.P. Albright, E.N. Shaposhnikova, H. Timko CERN, Geneva, Switzerland
	The CERN PS Booster is the first synchrotron in the LHC proton injection chain, it currently accelerates particles from 50 MeV to 1.4 GeV kinetic energy. Several upgrades foreseen by the LHC Injectors Upgrade Program will allow the beam to be accelerated from 160 MeV to 2 GeV after Long Shutdown 2 in 2021. The present RF systems will be replaced by a new one, based on Finemet technology. These and other improvements will help to increase the LHC luminosity by a factor of ten. In order to study beam stability in the longitudinal plane simulations have been performed with the CERN BLonD code, using an accurate longitudinal impedance model and a reliable estimation of the longitudinal space charge. Particular attention has been dedicated to the three main features that currently let the beam go stably through the ramp: Double RF operation in bunch-lengthening mode to reduce the transverse space charge tune spread, exploitation of feedback loops to damp dipole oscillations, and controlled longitudinal emittance blow-up. RF phase noise injection has been considered to study if it could complement or substitute the currently used method based on sinusoidal phase modulation.
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MOPR029	On the Impact of Non-Symplecticity of Space Charge Solvers	space-charge, simulation, optics, resonance	146
	M. Titze CERN, Geneva, Switzerland
	Funding: German Federal Ministry of Education and Research (BMBF) To guarantee long-term reliability in the predictions of a numerical integrator, it is a well-known requirement that the underlying map has to be symplectic. It is therefore important to examine in detail the impact on emittance growth and noise generation in case this condition is violated. We present a strategy of how to tackle this question and some results obtained for particular PIC and frozen space charge models.
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MOPR033	Beam Acceleration and Transition Crossing in the Fermilab Booster	impedance, simulation, booster, timing	160
	V.A. Lebedev, C.M. Bhat, J.-F. Ostiguy Fermilab, Batavia, Illinois, USA
	To suppress eddy currents, the Fermilab rapid cycling Booster synchrotron has no beam pipe; rather, its combined function dipoles are evacuated, exposing the beam directly to the magnet laminations. This arrangement significantly increases the resistive wall impedance of the dipoles and, in combination with the space charge impedance, substantially complicates longitudinal dynamics at transition. Voltage and accelerating phase profiles in the vicinity of transition are typically empirically optimized to minimize beam loss and emittance growth. In this contribution, we present results of experimental studies of beam acceleration near transition. Using comparisons between observed beam parameters and simulations, we obtain accurate calibrations for the RF program and extract quantitative information about parameters of relevance to the Booster laminated magnets longitudinal impedance model. The results are used to analyze transition crossing in the context of a future 50% increase in beam intensity planned for PIP-II, an upgrade of the Fermilab accelerating complex.
	Poster MOPR033 [0.231 MB]
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MOPL002	The DESIR Facility at GANIL-SPIRAL2: The Transfer Beam Lines	quadrupole, ion, diagnostics, optics	179
	L. Perrot, P. Blache, S. Rousselot IPN, Orsay, France
	Funding: French ANR, Investissements d'Avenir, EQUIPEX. Contract number ANR-11-EQPX-0012. The new ISOL facility SPIRAL2 is currently being built at GANIL, Caen France. The commissioning of the accelerator is in progress since 2015. SPIRAL2 will produce a large number of new radioactive ion beams (RIB) at high intensities. In 2019, the DESIR facility will receive beams from the upgraded SPIRAL1 facility of GANIL (stable beam and target fragmentation), from the S3 Low Energy Branch (fusion-evaporation and deep-inelastic reactions). In order to deliver the RIB to the experimental set-ups installed in the DESIR hall, 110 meters of beam line are studied since 2014. This paper will focus on the recent studies which have been done on these transfer lines: beam optics and errors calculations, quadrupoles, diagnostics and mechanical designs.
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MOPL003	Status of the Beam Dynamics Design of the New Post-Stripper DTL for GSI - FAIR	DTL, quadrupole, simulation, ion	184
	A. Rubin, D. Daehn, X. Du, L. Groening, M. Kaiser, S. Mickat GSI, Darmstadt, Germany
	The GSI UNILAC has served as injector for all ion species since 40 years. Its 10⁸ MHz Alvarez DTL providing acceleration from 1.4 MeV/u to 11.4 MeV/u has suffered from material fatigue and has to be replaced by a new section. The design of the new post-stripper DTL is now under development in GSI. An optimized drift tube shape increases the shunt impedance and varying stem orientations mitigate parasitic rf-modes. This contribution is on the beam dynamics layout.
	Poster MOPL003 [2.176 MB]
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MOPL005	The Simulation Study of Beam Dynamics for CSNS Linac During Beam Commissioning	DTL, simulation, rfq, linac	192
	Y. Yuan, H.F. Ji, S. Wang IHEP, Beijing, People's Republic of China J. Peng CSNS, Guangdong Province, People's Republic of China
	China Spallation Neutron Source (CSNS) is a high intensity accelerator based facility. Its accelerator consists of an H⁻ injector and a proton Rapid Cycling Synchrotron. The injector includes the front end and linac. The RFQ accelerates the beam to 3MeV, and then the Drift Tube Linac (DTL) accelerates it to 80MeV[1]. An Medium Energy Beam Transport (MEBT) matches RFQ and DTL, and the DTL consists of four tanks. Commissioning of the MEBT and the first DTL tank (DTL1) have been accomplished in the last run. Due to the difference of actual effective length and theoretical effective length of magnets in MEBT and DTL1, in order to compare its impact of beam transport, this paper takes a beam dynamics simulation on beam transport in MEBT and DTL1 with IMPACT-Z code[2]. Meanwhile, the transport of beam with different emittance in MEBT and DTL1 is studied because of the large emittance at RFQ exit. All the simulation includes magnet error and RF error.
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MOPL006	Beam Dynamics Study of C-Ads Injector-I With Developing P-Topo Code	rfq, simulation, space-charge, lattice	195
	Zh.C. Liu, C. Li, Q. Qin, F. Yan, Y.L. Zhao IHEP, Beijing, People's Republic of China
	A parallelized, time-dependent 3D particle simulation code is under developing to study the high-intensity beam dynamics in linear accelerators. The self-consistent space charge effect is taken into account with the Particle-In-Cell (PIC) method. In this paper, the structure of program and the parallel strategy are demonstrated. Then, we show the results of code verification and benchmarking. It is proved that the solvers in P-TOPO code and parallel strategy are reliable and efficient. Finally, the beam dynamics simulation of C-ADS Injector-I at IHEP are launched with P-TOPO and other codes. The possible reasons for the differences between results given by separated codes are also proposed.
	Poster MOPL006 [2.169 MB]
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MOPL009	Analytical Approach for Achromatic Structure Study and Design	quadrupole, dipole, cyclotron, factory	203
	H.Y. Barminova MEPhI, Moscow, Russia A.S. Chikhachev Allrussian Electrotechnical Institute, Moskow, Russia
	The analytical approach is proposed to study the various achromatic structures. The method is based on the self-consistent time-dependent models, which allow to describe the dynamics of both continuous and bunched beam in external magnetic fields. The fully kinetic models are implemented in this approach. The kinetic distribution functions dependent on the motion integrals allow to obtain accurate Vlasov equation solutions as KV-model does it. The method allows to solve the envelope equation both analytically and by ODE system numerical integration, and to predict the beam phase portrait behavior in magnetic fields of the structure. The advantages of the method are the possibility of easy scaling and the wide physical generality, which is important for the multi-parameter problem of the high-intensity high-brightness beam formation. The results of the method application for the bending magnets and the quadrupoles are presented.
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MOPL017	High Power and High Duty Cycle Slit and Grid System for Hadron Accelerator Commissioning	simulation, scattering, rfq, DTL	226
	B. Cheymol, A. Ponton ESS, Lund, Sweden
	Transverse emittance is one of the key measurements to be performed during the commissioning of the low energy sections of an hadron linac. The good knowledge of the beam transverse phase space allows a safe and efficient operation of the machines by using the results of the measurement for beam dynamic simulations. In this paper we will discuss the accuracy and the limits of the transverse emittance measurement performed with the slit-grid method based on the ESS beam parameters at the RFQ (beam energy equal to 3.62 MeV) and DTL tank 1 (beam energy equal to 21 MeV) output.
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TUAM3X01	Identification and Reduction of the CERN SPS Impedance	impedance, flattop, vacuum, simulation	260
	E.N. Shaposhnikova, T. Argyropoulos, T. Bohl, A. Lasheen, J. Repond, H. Timko CERN, Geneva, Switzerland
	The first SPS impedance reduction programme has been completed in 2001, preparing the ring for its role as an injector of the LHC. This action has eliminated microwave instability on the SPS flat bottom and later nominal beam could be delivered to the LHC. The High Luminosity (HL-) LHC project is based on beam with twice higher intensity than the nominal one. One of the important SPS intensity limitations are longitudinal instabilities with minimum threshold reached on the 450 GeV flat top. In this paper the work which was carried on to identify the impedance sources driving these instabilities is described together with the next campaign of the SPS impedance reduction planned by the LHC Injector Upgrade (LIU) project. The present knowledge of the SPS transverse impedance is also presented.
	Slides TUAM3X01 [6.457 MB]
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TUAM4X01	Electron Cloud in the CERN Accelerator Complex	operation, electron, simulation, quadrupole	266
	G. Rumolo, H. Bartosik, E. Belli, G. Iadarola, K.S.B. Li, L. Mether, A. Romano CERN, Geneva, Switzerland M. Schenk EPFL, Lausanne, Switzerland
	Operation with closely spaced bunched beams causes the build up of an Electron Cloud (EC) in both the LHC and the two last synchrotrons of its injector chain (PS and SPS). Pressure rise and beam instabilities are observed at the PS during the last stage of preparation of the LHC beams. The SPS was affected by coherent and incoherent emittance growth along the LHC bunch train over many years, before scrubbing has finally suppressed the EC in a large fraction of the machine. When the LHC started regular operation with 50 ns beams in 2011, EC phenomena appeared in the arcs during the early phases, and in the interaction regions with two beams all along the run. Operation with 25 ns beams (late 2012 and 2015), which is nominal for LHC, has been hampered by EC induced high heat load in the cold arcs, bunch dependent emittance growth and degraded beam lifetime. Dedicated and parasitic machine scrubbing is presently the weapon used at the LHC to combat EC in this mode of operation. This talk summarises the EC experience in the CERN machines (PS, SPS, LHC) and highlight the dangers for future operation with more intense beams as well as the strategies to mitigate or suppress the effect.
	Slides TUAM4X01 [9.785 MB]
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TUAM6X01	First Analysis of the Space Charge Effects on a Third Order Coupled Resonance	resonance, space-charge, synchrotron, simulation	278
	G. Franchetti GSI, Darmstadt, Germany S.S. Gilardoni, A. Huschauer, F. Schmidt, R. Wasef CERN, Geneva, Switzerland
	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.
	Slides TUAM6X01 [7.183 MB]
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TUPM3X01	R&D on Beam Injection and Bunching Schemes in the Fermilab Booster	booster, injection, linac, simulation	293
	C.M. Bhat Fermilab, Batavia, Illinois, USA
	Funding: Work supported by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy Fermilab is committed to upgrade its accelerator complex towards the intensity frontier by making a substantial increase in the average beam power delivered to the neutrino and muon programs pursuing HEP research in the lepton sector. Proton Improvement Plan (PIP) enables us to provide 700 kW beam power by the end of this year. By the middle of next decade, the foreseen PIP–II replaces the existing LINAC, a 400 MeV injector to the Booster, by an 800 MeV superconducting LINAC with beam power increased by >50%. In any case, the Fermilab Booster, an 8 GeV injector to the MI, is going to play a very significant role for the next two decades. In this context, we have recently developed an innovative beam injection scheme for the Booster called "early injection scheme" and put into operation. This novel scheme has a potential to increase the Booster beam intensity from the PIP design goal by ~40%. Some benefits of the scheme have already been seen so far. In this talk, I will present, principle of the scheme, results from beam experiments, current status and future plans for the early beam injection scheme. This scheme fits well with the current and future programs at Fermilab. Author would like to thank S. Chaurize, C. Drennan, F. Garcia, B. Hendrick, W. Pellico, K. Seiya, T. Sullivan, K. Triplett and A. Waller,
	Slides TUPM3X01 [7.081 MB]
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TUAM7Y11	High Current Uranium Beam Measurements at GSI-UNILAC for FAIR	brilliance, target, ion, proton	319
	W.A. Barth, A. Adonin, Ch.E. Düllmann, M. Heilmann, R. Hollinger, E. Jäger, O.K. Kester, J. Khuyagbaatar, J. Krier, E. Plechov, P. Scharrer, W. Vinzenz, H. Vormann, A. Yakushev, S. Yaramyshev GSI, Darmstadt, Germany Ch.E. Düllmann, J. Khuyagbaatar, P. Scharrer, A. Yakushev HIM, Mainz, Germany Ch.E. Düllmann Johannes Gutenberg University Mainz, Institut of Nuclear Chemistry, Mainz, Germany P. Scharrer Mainz University, Mainz, Germany S. Yaramyshev MEPhI, Moscow, Russia
	In the context of an advanced machine investigation program supporting the ongoing UNILAC (Universal Linear Accelerator) upgrade program, a new uranium beam intensity record (10 emA, U²⁹⁺) at very high beam brilliance was achieved last year in a machine experiment campaign at GSI. The UNILAC as well as the heavy ion synchrotron SIS18 will serve as a high current heavy ion injector for the new FAIR (Facility for Antiproton and Ion Research) synchrotron SIS100. Results of the accomplished high current uranium beam measurements applying a newly developed pulsed hydrogen gas stripper (at 1.4'MeV/u) will be presented. The paper will focus on the evaluation and analysis of the measured beam brilliance and further implications to fulfil the FAIR heavy ion high intensity beam requirements.
	Slides TUAM7Y11 [2.437 MB]
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TUPM2Y01	Beam Commissioning Results for the CSNS MEBT and DTL-1	DTL, rfq, linac, cavity	329
	J. Peng, M.T. Li, X.H. Lu CSNS, Guangdong Province, People's Republic of China Y.W. An, S. Fu, L. Huang, M.Y. Huang, Y. Li, Z.P. Li, Y.D. Liu, S. Wang, S.Y. Xu, Y. Yuan IHEP, Beijing, People's Republic of China
	The China Spallation Neutron Source (CSNS) is designed to deliver a 1.6GeV proton beam to a solid metal target for neutron scattering research. It will be constructed in two phases. In the 1st phase, the beam power is designed to be 100kW. In the 2nd phase, the beam power will be upgraded to 500kW by doubling the linac output energy and beam current. The accelerator complex consists of a 50keV H⁻ ion source, a 3MeV Radio Frequency Quadrupole (RFQ), a 80MeV Drift tube Linac (DTL), and a 1.6GeV rapid-cycling synchrotron (RCS). Until March 2016, the front end and the first tank of DTL have been fully commissioned. The primary design goals of peak current, transverse emittance and beam energy have been achieved. This paper reports on the methods and the results of the commissioning.
	Slides TUPM2Y01 [2.398 MB]
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TUPM4Y01	IFMIF-EVEDA RFQ, Measurement of Beam Input Conditions and Preparation to Beam Commissioning	rfq, simulation, solenoid, space-charge	338
	M. Comunian, L. Bellan, E. Fagotti, A. Pisent INFN/LNL, Legnaro (PD), Italy L. Bellan Univ. degli Studi di Padova, Padova, Italy
	The commissioning phase of the IFMIF-EVEDA RFQ requires a complete beam characterization with simulations and measurements of the beam input from the IFMIF-EVEDA ion source and LEBT, in order to reach the RFQ input beam parameters. In this article the simulations of source LEBT RFQ will be reported with the corresponding set of measurements done on the Ion source and LEBT.
	Slides TUPM4Y01 [7.230 MB]
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TUPM6Y01	Commissioning of C-ADS Injector I	rfq, cavity, solenoid, proton	348
	J.S. Cao, H. Geng, R.L. Liu, C. Meng, Y.F. Sui, F. Yan, Q. Ye IHEP, Beijing, People's Republic of China
	As a test facility, the design goal of C-ADS Injector I is a 10mA, 10MeV CW proton linac, which uses a 3.2MeV normal conducting RFQ and superconducting single-spoke cavities for accelerating. The RF frequency of C-ADS Injector I accelerator is 325 MHz. In accordance to the progress of construction and considering the technical difficulties, the beam commissioning of C-ADS Injector I is carried out in 3 phases: Phase 1, with ECRIS + LEBT + RFQ + MEBT + TCM (two superconducting cavities), to reach 3.6 MeV; Phase 2, with ECRIS + LEBT + RFQ + MEBT + CM1 (seven superconducting cavities), to reach 5 MeV; Phase 3, with ECRIS + LEBT + RFQ + MEBT + CM¹⁺ CM2 (same as CM1), to finally achieve the design goal of C-ADS Injector I. This paper summarizes the beam commissioning in 3 phases and focusing on the third phase.
	Slides TUPM6Y01 [3.617 MB]
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WEAM1X01	Code Bench-Marking for Long-Term Tracking and Adaptive Algorithms	space-charge, simulation, resonance, experiment	357
	F. Schmidt, H. Bartosik, A. Huschauer, A. Oeftiger, M. Titze CERN, Geneva, Switzerland Y.I. Alexahin, J.F. Amundson, V.V. Kapin, E.G. Stern Fermilab, Batavia, Illinois, USA G. Franchetti GSI, Darmstadt, Germany J.A. Holmes ORNL, Oak Ridge, Tennessee, USA
	At CERN we have ramped up a program to investigate space charge effects in the LHC pre-injectors with high brightness beams and long storage times. This in view of the LIU upgrade project for these accelerators. These studies require massive simulation over large number of turns. To this end we have been looking at all available codes and started collaborations on code development with several laboratories: pyORBIT from SNS, SYNERGIA from Fermilab, MICROMAP from GSI and our in-house MAD-X code with an space charge upgrade. We have agreed with our collaborators to bench-mark all these codes in the framework of the GSI bench-marking suite, in particular the main types of frozen space charge and PIC codes are being tested. We also include a study on the subclass of purely frozen and the adaptive frozen modes both part of MAD-X in comparison with the purely frozen MICROMAP code. Last, we will report on CERN's code development effort to understand and eventually overcome the noise issue in PIC codes. J. Coupard et al., ‘‘LHC Injectors Upgrade, Technical Design Report, Vol. I: Protons'', LIU Technical Design Report (TDR), CERN-ACC-2014-0337.
	Slides WEAM1X01 [2.348 MB]
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WEAM5X01	Beam-Dynamics Issues in the FCC	luminosity, radiation, hadron, collider	373
	F. Zimmermann, W. Bartmann, M. Benedikt, M.I. Besana, R. Bruce, O.S. Brüning, X. Buffat, F. Burkart, H. Burkhardt, S. Calatroni, F. Cerutti, S.D. Fartoukh, M. Fiascaris, C. Garion, B. Goddard, B.J. Holzer, W. Höfle, J.M. Jowett, R. Kersevan, R. Martin, L. Mether, A. Milanese, T. Pieloni, S. Redaelli, G. Rumolo, B. Salvant, M. Schaumann, D. Schulte, E.N. Shaposhnikova, L.S. Stoel, C. Tambasco, R. Tomás, D. Tommasini CERN, Geneva, Switzerland J.L. Abelleira, E. Cruz Alaniz, A. Seryi JAI, Oxford, United Kingdom R.B. Appleby UMAN, Manchester, United Kingdom P. Bambade, A. Faus-Golfe, J. Molson LAL, Orsay, France J. Barranco EPFL, Lausanne, Switzerland J.-L. Biarrotte, A. Lachaize IPN, Orsay, France O. Boine-Frankenheim, U. Niedermayer TEMF, TU Darmstadt, Darmstadt, Germany M. Boscolo, F. Collamati, A. Drago INFN/LNF, Frascati (Roma), Italy A. Chancé CEA, Gif-sur-Yvette, France B. Dalena, J. Payet CEA/IRFU, Gif-sur-Yvette, France J.D. Fox, G. Stupakov SLAC, Menlo Park, California, USA G. Guillermo Cantón CINVESTAV, Mérida, Mexico S. Khan, B. Riemann DELTA, Dortmund, Germany V. Kornilov GSI, Darmstadt, Germany T.M. Mitsuhashi, K. Ohmi KEK, Ibaraki, Japan
	Funding: European Commission under the Capacities 7th Framework Programme project EuCARD-2, grant agreement 312453, and the HORIZON 2020 project EuroCirCol, grant agreement 654305. Also by the German BMBF. The international Future Circular Collider (FCC) study is designing hadron, lepton and lepton-hadron colliders based on a new 100 km tunnel in the Geneva region. The main focus and ultimate goal of the study are high-luminosity proton-proton collisions at a centre-of-mass energy of 100 TeV, using 16 T Nb3Sn dipole magnets. Specific FCC beam dynamics issues are related to the large circumference, the high brightness - made available by radiation damping -, the small geometric emittance, unprecedented collision energy and luminosity, the huge amount of energy stored in the beam, large synchrotron radiation power, plus the injection scenarios. In addition to the FCC-hh proper, also a High-Energy LHC (HE-LHC) is being explored, using the FCC-hh magnet technology in the existing LHC tunnel, which can yield a centre-of-mass energy around 25 TeV.
	Slides WEAM5X01 [10.402 MB]
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WEAM6X01	Studies of High Intensity Proton FFAGs at RAL	injection, proton, linac, lattice	379
	C.R. Prior STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The paper describes studies of high intensity proton accelerators for a next-generation source of short-pulse spallation neutrons. Along with conventional designs using rapid cycling synchrotrons, the long-term nature of the project provides scope for novel accelerator designs and developing technological ideas. A range of FFAG options is under consideration for the main spallation driver. Theory and simulation in the UK are combined with experimental studies of FFAGs in Japan, and a small prototype FFAG ring is planned to go on the FETS injector at RAL for essential R&D. The paper covers the broad scope of the programme and details the success of the study to date.
	Slides WEAM6X01 [12.105 MB]
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WEPM1X01	Performance of Linac-4 Instrumentation During Commissioning	laser, linac, DTL, cavity	385
	U. Raich CERN, Geneva, Switzerland
	Linac-4 is CERN’s new H⁻ Linac, which will replace the aging Linac-2 proton machine. Linac-4 is being built and commissioned in stages. While the machine is permanently equipped with the standard beam instrumentation necessary to ensure smooth operation, three dedicated measurement benches have also been designed to commission the source and LEBT at 45 keV, the MEBT and its chopper at 3 MeV as well as the first DTL tank at 12 MeV and finally the full DTL at 50 MeV and CCDTL at 100 MeV. The beam after the PIMS structures at the Linac’s full energy of 160 MeV will be sent to a beam dump and commissioned with permanently installed instruments. Installation and commissioning of the machine up to the CCDTL is now complete. This contribution will present the results from the various commissioning stages, showing the performance of the various diagnostic devices used and comparing the data obtained to simulations.
	Slides WEPM1X01 [10.600 MB]
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WEPM7X01	The Application of the Optimization Algorithm in the Collimation System for CSNS/RCS	collimation, acceleration, space-charge, simulation	397
	H.F. Ji, M.Y. Huang, Y. Jiao, N. Wang, S. Wang, S.Y. Xu IHEP, Beijing, People's Republic of China
	The robust conjugate direction search (RCDS) method, which is developed by X. Huang from the SLAC National Accelerator Laboratory, has high tolerance against noise in beam experiments and thus can find an optimal solution effectively and efficiently. In this paper, the RCDS method is used to optimize the beam collimation system for Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS). A two-stage beam collimation system was designed to localize the beam loss in the collimation section in CSNS/RCS. The parameters of secondary collimators are optimized with RCDS algorithm based on detailed tracking with the ORBIT program for a better performance of the collimation system. The study presents a way to quickly find an optimal parameter combination of the secondary collimators for a machine model for preparation for CSNS/RCS commissioning.
	Slides WEPM7X01 [1.137 MB]
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WEPM1Y01	Emittance Reconstruction Techniques in Presence of Space Charge Applied During the Linac4 Beam Commissioning	linac, space-charge, diagnostics, DTL	433
	V.A. Dimov, J.-B. Lallement, A.M. Lombardi CERN, Geneva, Switzerland R. Gaur RRCAT, Indore, India
	The classical emittance reconstruction technique, based on analytic calculations using transfer matrices and beam profile measurements, is reliable only if the emittance is conserved and the space charge forces are negligible in the beamline between the reconstruction and measurement points. The effects of space charge forces prevent this method from giving sound results up to a relativistic beta of about 0.5 and make it inapplicable to the Linac4 commissioning at 50 and 100 MeV. To compensate for this drawback we have developed a dedicated technique, the forward method, which extends the classical method by combining it with an iterative process of multiparticle tracking including space charge forces. The forward method, complemented with a tomographic reconstruction routine, has been applied to transverse and longitudinal emittance reconstruction during the Linac4 beam commissioning. In this paper we describe the reconstruction process and its application during Linac4 beam commissioning.
	Slides WEPM1Y01 [1.923 MB]
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WEPM8Y01	Simulation of Space-Charge Compensation of a Low-Energy Proton Beam in a Drift Section	simulation, electron, ion, proton	458
	D. Noll, M. Droba, O. Meusel, U. Ratzinger, K. Schulte IAP, Frankfurt am Main, Germany
	Space-charge compensation provided by the accumulation of particles of opposing charge in the beam potential is an important effect occuring in magnetostatic low energy beam transport sections of high-intensity accelerators. An improved understanding of its effects might provide valuable input for the design of these beam lines. One approach to model the compensation process are Particle-in-Cell (PIC) simulations including residual gas ionisation. In simulations of a drifting proton beam, using the PIC code bender [1], some features of thermal equilibrium for the compensation electrons were found. This makes it possible to predict their spatial distribution using the Poisson-Boltzmann equation and thus the influence on beam transport. In this contribution, we will provide a comparison between the PIC simulations and the model as well as some ideas concerning the source of the (partial) thermalization. [1] D. Noll, M. Droba, O. Meusel, U. Ratzinger, K. Schulte, C. Wiesner - The Particle-in-Cell Code Bender and Its Application to Non-Relativistic Beam Transport, WEO4LR02, Proc. of HB2014
	Slides WEPM8Y01 [2.203 MB]
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THAM6X01	The Path to 1 MW: Beam Loss Control in the J-PARC 3-GeV RCS	injection, resonance, acceleration, power-supply	480
	H. Hotchi, H. Harada, S. Kato, M. Kinsho, K. Okabe, P.K. Saha, Y. Shobuda, F. Tamura, N. Tani, Y. Watanabe, K. Yamamoto, M. Yamamoto, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The J-PARC 3-GeV RCS started 1-MW beam test from October 2014, and successfully achieved a 1-MW beam acceleration in January 2015. The most important issues in realizing such a high power routine beam operation are control and minimization of beam loss. This talk will present the recent progress of 1-MW beam tuning, especially focusing on our approaches to beam loss issues.
	Slides THAM6X01 [1.849 MB]
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THPM1X01	Typology of Space Charge Resonances	resonance, space-charge, lattice, focusing	486
	I. Hofmann GSI, Darmstadt, Germany
	The existence of structural space charge resonant effects in otherwise linear periodic focusing systems is well-known, but referred to in a variety of languages and contexts. We show here that for short bunched beams a ‘‘classification'' in two major groups is possible, e.g. parametric resonances or instabilities on the one hand and single particle type space charge resonances on the other hand. The primary feature of distinction is that for the former the driving space charge force initially exists on the noise level (rms or higher order mismatch) only and gets amplified parametrically, hence an entirely coherent response; for the latter the driving space charge multipole is part of the initial density profile and the coherent response is weak. In the extreme limit of KV beams only parametric resonances (instabilities) exist, and in principle in all orders. For waterbag or Gaussian distributions we find half-integer parametric resonances only up to fourth order, but evidence for single particle resonances in all orders up to tenth have been identified.
	Slides THPM1X01 [3.094 MB]
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THPM4X01	Resonances and Envelope Instability in High Intensity Linear Accelerators	resonance, lattice, space-charge, linac	491
	D. Jeon, J.-H. Jang, H. Jin IBS, Daejeon, Republic of Korea
	Funding: This work was supported by the Institute for Basic Science funded by the Ministry of Science, ICT and Future Planning (MSIP) and the NRF of Korea under Contract 2013M7A1A1075764. Understanding of space charge effects has grown and recent studies have led to the findings of resonances of high intensity linear accelerators. Lately the sixth order resonance of high intensity linear accelerators was reported, along with the in-depth studies on the fourth order resonance and the envelope instability. Experiment studies on space charge resonances were reported. This paper reviews the resonances of high intensity linear accelerators such as the 4σ =360deg, and the 6σ =720deg resonances, along with the envelope instability.
	Slides THPM4X01 [3.279 MB]
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THPM6X01	Space Charge Effects in FFAG	space-charge, closed-orbit, lattice, betatron	499
	M. Haj Tahar, F. Méot BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Understanding space charge effects in FFAG is crucial in order to assess their potential for high power applications. This paper shows that, to carry out parametric studies of these effects in FFAG, the average field index of the focusing and defocusing magnets are the natural parametrization. Using several classes of particle distribution functions, we investigate the effects of space charge forces on the non-linear beam dynamics of FFAG and provide stability diagrams for an FFAG-like lattice. The method developed in this study is mainly applicable to systems with slowly varying parameters, i.e slow acceleration.
	Slides THPM6X01 [2.171 MB]
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THPM9X01	Space Charge Effects and Mitigation in the CERN PS Booster, in View of the Upgrade	injection, booster, space-charge, simulation	517
	E. Benedetto, M. Cieslak-Kowalska, V. Forte, F. Schmidt CERN, Geneva, Switzerland M. Cieslak-Kowalska EPFL, Lausanne, Switzerland V. Forte Université Blaise Pascal, Clermont-Ferrand, France
	The CERN PS Booster (PSB) is presently running with a space-charge tune spread larger than 0.5 at injection. Since the High Luminosity LHC (HL-LHC) will require beams with twice the intensity and brightness of today, the LHC Injector Upgrade (LIU) Project is putting in place an upgrade program for all the injector chain and, in particular, it relies on the important assumption that the PS Booster can successfully produce these beams after the implementation of the 160 MeV H⁻ injection from Linac4. This contribution describes the studies (measurements and simulations) that have been carried out to confirm that the PSB can indeed perform as needed in terms of beam brightness for the future HL-LHC runs. The importance of the mitigation measures already in place, such as the correction of the half-integer line, and the effects of non-linear resonances on the beam are also discussed.
	Slides THPM9X01 [6.786 MB]
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THAM1Y01	Beam Commissioning of C-ADS Linac Instrumentation	linac, rfq, instrumentation, cavity	529
	Y.F. Sui, J.S. Cao, J. He, H.Z. Ma, L. Wang, S.J. Wei, Q. Ye, L. Yu, J.H. Yue, X.Y. Zhao, Y. Zhao IHEP, People's Republic of China
	Funding: Work supported by China ADS Project (XDA03020000) and the National Natural Science Foundation of China (NO. 11205172, NO. 11475204). The China Accelerator Driven Subcritical system (C-ADS) linac, which is composed of an ECR ion source, a low energy beam transport line (LEBT), a radio frequency quadrupole accelerator (RFQ), a medium energy beam transport line (MEBT) and cryomodules with SRF cavities to boost the energy up to 10 MeV. The injector linac will be equipped with beam diagnostics to measure the beam position, the transverse profile and emittance, the beam phase as well as beam current and beam losses. Though many are conventional design, They can provide efficient operation of drive linac. This paper gives an overview and detail in beam commissioning of C-ADS linac beam instrumentation.
	Slides THAM1Y01 [7.594 MB]
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THAM5Y01	Path to Beam Loss Reduction in the SNS Linac Using Measurements, Simulation and Collimation	linac, optics, collimation, operation	548
	A.V. Aleksandrov, A.P. Shishlo ORNL, Oak Ridge, Tennessee, USA
	Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. The SNS linac operation at its design average power currently is not limited by uncontrolled beam loss. However, further reduction of the beam loss remains an important aspect of the SNS linac tune up and operation. Even small “acceptable” beam loss leads to long term degradation of the accelerator equipment. The current state of model-based tuning at SNS leaves an unacceptably large residual beam loss level and has to be followed by an empirical, sometimes random, adjustment of many parameters to reduce the loss. This talk will discuss a set of coordinated efforts to develop tools for large dynamic range measurements, simulation and collimation in order to facilitate low loss linac tuning.
	Slides THAM5Y01 [7.186 MB]
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THPM7Y01	A New RFQ Model and Symplectic Multi-Particle Tracking in the IMPACT Code Suite	rfq, space-charge, simulation, proton	562
	J. Qiang LBNL, Berkeley, California, USA L. Li, Z. Wang PKU, Beijing, People's Republic of China
	The IMPACT code suite is a self-consistent parallel three-dimensional beam dynamics simulation toolbox that combines the magnetic optics method and the parallel particle-in-cell method. It has been widely used to study high intensity/high brightness beams in many accelerators. In this paper, we will report on recent improvements to the code such as the capability to model RFQ in time domain and symplectic multi-particle tracking with a gridless spectral solver for space-charge simulation.
	Slides THPM7Y01 [8.794 MB]
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THPM9Y01	An Advanced Procedure for Longitudinal Beam Matching for SC CW Heavy Ion Linac With Variable Output Energy	cavity, linac, ion, acceleration	571
	S. Yaramyshev, W.A. Barth, V. Gettmann, M. Heilmann, S. Mickat, M. Miski-Oglu GSI, Darmstadt, Germany K. Aulenbacher, W.A. Barth, V. Gettmann, S. Mickat, M. Miski-Oglu HIM, Mainz, Germany K. Aulenbacher IKP, Mainz, Germany W.A. Barth, S. Yaramyshev MEPhI, Moscow, Russia M. Heilmann IAP, Frankfurt am Main, Germany
	A multi-stage programm for the developmnet of a heavy ion superconducting (SC) continuous wave (CW) linac is in progress at HIM (Mainz, Germany), GSI (Darmstadt, Germany) and IAP (Frankfurt, Germany). The main beam acceleration is provided by up to nine multi-gap CH cavities. Due to variable beam energy, which coud be provided by each cavity separate, a longitudinal beam matching to each cavity is extremely important. The linac should provide the beam for physics experiments, smothly varying the output particle energy from 3.5 to 7.3 MeV/u, simultaneously keeping high beam quality. A dedicated algorythm for such a complicate matching, providing for the optimum machine settings (voltage and rf phase for each cavity), has been developed. The description of method and the obtained reasuts are discussed in this paper.
	Slides THPM9Y01 [1.585 MB]
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Paper

Title

Other Keywords

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MOAM2P20

The LINAC4 Project

linac, cavity, DTL, injection

1

A.M. Lombardi
CERN, Geneva, Switzerland

Linac4 is a normal conducting, 160 MeV H⁻ ion accelerator that is being constructed within the scope of the LHC injectors upgrade project. Linac4 will be connected to the Proton Synchrotron Booster (PSB) during the next long LHC shut-down and it will replace the current 50 MeV hadron linac, Linac2. Linac4 is presently being commissioned, with the aim of achieving the final energy at the end of the year. A test of the injection chicane and a reliability run will follow. The beam commissioning, in steps of increasing energy, has been prepared by an extended series of studies and interlaced with phases of installation. In this paper we will detail the beam dynamics challenges and we will report on the commissioning results.

Slides MOAM2P20 [27.527 MB]

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MOPR004

H⁻ Charge Exchange Injection for XiPAF Synchrotron

injection, proton, synchrotron, dipole

49

H.J. Yao, X. Guan, G.R. Li, X.W. Wang, Q.Z. Xing, S.X. Zheng
TUB, Beijing, People's Republic of China

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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MOPR016

Mitigation of Numerical Noise for Beam Loss Simulations

simulation, space-charge, ion, proton

90

F. Kesting
IAP, Frankfurt am Main, Germany
G. Franchetti
GSI, Darmstadt, Germany

Numerical noise emerges in self-consistent simulations of charged particles, and its mitigation is investigated since the first numerical studies in plasma physics. In accelerator physics, recent studies find an artificial diffusion of the particle beam due to numerical noise in particle-in-cell tracking, which is of particular importance for high intensity machines with a long storage time, as the SIS100 at FAIR or in context of the LIU upgrade at CERN. In beam loss simulations for these projects artificial effects must be distinguished from physical beam loss. Therefore, it is important to relate artificial diffusion to artificial beam loss, and to choose simulation parameters such that physical beam loss is well resolved. As a practical tool, we therefore suggest a scaling law to find optimal simulation parameters for a given maximum percentage of acceptable artificial beam loss.

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MOPR017

Status of the Beam Instrumentation System of CSNS

DTL, neutron, linac, rfq

95

J.L. Sun, J. Peng, R.Y. Qiu, T. Yang
CSNS, Guangdong Province, People's Republic of China
W.L. Huang, F. Li, P. Li, M. Meng, J.M. Tian, T.G. Xu, Zh.H. Xu, L. Zeng
IHEP, Beijing, People's Republic of China

The first section DTL commissioning of China Spallation Neutron Source (CSNS) project has been successful finished in January, 2016. The H⁻ beam can be accelerated to 21.6 MeV at peak current 18 mA, achieved the design point. Different elements of the beam instrumentation system have been tested during the commissioning, including BPM, CT, FCT, WS, EM, BLM, and corresponding electronics and control systems. High accuracy phase measurement (precision @ ±1°) system has been started into operation. Beam loss monitor (BLM) for low energy, 3 MeV to 21.6 MeV, has been tested too, and got very positive results. For the LRBT, RCS and RTBT, different type wire scanner, BPM, WCM, CT were designed. The monitors fit for the high-radiation environments were considered. All the physical design work has been finished, and being manufactured. Lab test will be started in June and the LINAC commissioning (beam energy up to 80 MeV) will be started in August.

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MOPR018

XAL Applications Development for CSNS Transport Lines

database, linac, interface, controls

98

Y. Li, Z.P. Li, W.B. Liu
IHEP, Beijing, People's Republic of China
J. Peng
CSNS, Guangdong Province, People's Republic of China

XAL is an application programming framework initially developed at the Spallation Neutron Source (SNS). It has been employed as a part of control system via con-nection to EPICS to provide application programs for beam commissioning at the China Spallation Neutron Source (CSNS). Several XAL-based applications have been developed for Beam Transport line at CSNS and successfully applied in the MEBT and DTL-1 beam commissioning. These applications will be discussed in this paper.

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MOPR020

Space Charge Effects of High Intensity Beams at BRing

resonance, simulation, injection, betatron

101

J. Li, J.C. Yang
IMP/CAS, Lanzhou, People's Republic of China

Funding: Work supported by NSFC (Grant No. 11475235)
Space charge effects perform one of the main intensity limitations for low energy synchrotron. Large tune spread and crossing resonance stop-bands can hardly be avoided for intensive heavy ion beam at high intensity. Several subjects like Betatron and structure resonance, and tune spread are discussed. Simulations are carried out for 238U³⁴⁺ focusing on emittance and intensity change during RF capture at the injection energy at the booster ring of the High Intensity heavy ion Accelerator Facility (HIAF).
lijie@impcas.ac.cn

Poster MOPR020 [1.157 MB]

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MOPR021

Overview of the ESSnuSB Accumulator Ring

linac, injection, space-charge, simulation

105

M. Olvegård, T.J.C. Ekelöf
Uppsala University, Uppsala, Sweden
E. Benedetto, M. Cieslak-Kowalska, M. Martini, H.O. Schönauer, E.H.M. Wildner
CERN, Geneva, Switzerland

The European Spallation Source (ESS) is a research center based on the world’s most powerful proton driver, 2.0 GeV, 5 MW on target, currently under construction in Lund. With an increased pulse frequency, the ESS linac could deliver additional beam pulses to a neutrino target, thus giving an excellent opportunity to produce a high-performance ESS neutrino Super-Beam (ESSnuSB). The focusing system surrounding the neutrino target requires short proton pulses. An accumulator ring and acceleration of an H⁻ beam in the linac for charge-exchange injection into the accumulator could provide such short pulses. In this paper we present an overview of the work with optimizing the accumulator design and the challenges of injecting and storing 1.10¹⁵ protons per pulse from the linac. In particular, particle tracking simulations with space charge will be described.

Poster MOPR021 [2.731 MB]

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MOPR022

Longitudinal Particle Tracking Code for a High Intensity Proton Synchrotron

acceleration, space-charge, synchrotron, beam-loading

110

M. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

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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MOPR023

Interpretation of Wire-Scanner Asymmetric Profiles in a Low-Energy Ring

space-charge, scattering, simulation, booster

115

M. Cieslak-Kowalska, E. Benedetto
CERN, Geneva, Switzerland

In the CERN PS Booster, wire-scanner profile measurements performed at injection energy are affected by a strong asymmetry. The shape was reproduced with the code pyOrbit, assuming that the effect is due to the beam evolution during the scans, under the influence of space-charge forces and Multiple Coulomb Scattering at the wire itself. Reproducing the transverse profiles during beam evolution allows to use them reliably as input for simulation benchmarking.

Poster MOPR023 [0.482 MB]

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MOPR025

Space Charge Modules for PyHEADTAIL

GPU, space-charge, simulation, vacuum

124

A. Oeftiger
CERN, Geneva, Switzerland
S. Hegglin
ETH, Zurich, Switzerland

Funding: CERN, Doctoral Studentship and EPFL, Doctorate
PyHEADTAIL is a 6D tracking tool developed at CERN to simulate collective effects. We present recent developments of the direct space charge suite, which is available for both the CPU and GPU. A new 3D particle-in-cell solver with open boundary conditions has been implemented. For the transverse plane, there is a semi-analytical Bassetti-Erskine model as well as 2D self-consistent particle-in-cell solvers with both open and closed boundary conditions. For the longitudinal plane, PyHEADTAIL offers line density derivative models. Simulations with these models are benchmarked with experiments at the injection plateau of CERN's Super Proton Synchrotron.

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MOPR026

Space Charge Mitigation With Longitudinally Hollow Bunches

space-charge, synchrotron, resonance, injection

130

A. Oeftiger, S. Hancock, G. Rumolo
CERN, Geneva, Switzerland

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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MOPR028

CERN PS Booster Longitudinal Dynamics Simulations for the Post-LS2 Scenario

space-charge, injection, simulation, impedance

140

D. Quartullo, S.C.P. Albright, E.N. Shaposhnikova, H. Timko
CERN, Geneva, Switzerland

The CERN PS Booster is the first synchrotron in the LHC proton injection chain, it currently accelerates particles from 50 MeV to 1.4 GeV kinetic energy. Several upgrades foreseen by the LHC Injectors Upgrade Program will allow the beam to be accelerated from 160 MeV to 2 GeV after Long Shutdown 2 in 2021. The present RF systems will be replaced by a new one, based on Finemet technology. These and other improvements will help to increase the LHC luminosity by a factor of ten. In order to study beam stability in the longitudinal plane simulations have been performed with the CERN BLonD code, using an accurate longitudinal impedance model and a reliable estimation of the longitudinal space charge. Particular attention has been dedicated to the three main features that currently let the beam go stably through the ramp: Double RF operation in bunch-lengthening mode to reduce the transverse space charge tune spread, exploitation of feedback loops to damp dipole oscillations, and controlled longitudinal emittance blow-up. RF phase noise injection has been considered to study if it could complement or substitute the currently used method based on sinusoidal phase modulation.

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MOPR029

On the Impact of Non-Symplecticity of Space Charge Solvers

space-charge, simulation, optics, resonance

146

M. Titze
CERN, Geneva, Switzerland

Funding: German Federal Ministry of Education and Research (BMBF)
To guarantee long-term reliability in the predictions of a numerical integrator, it is a well-known requirement that the underlying map has to be symplectic. It is therefore important to examine in detail the impact on emittance growth and noise generation in case this condition is violated. We present a strategy of how to tackle this question and some results obtained for particular PIC and frozen space charge models.

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MOPR033

Beam Acceleration and Transition Crossing in the Fermilab Booster

impedance, simulation, booster, timing

160

V.A. Lebedev, C.M. Bhat, J.-F. Ostiguy
Fermilab, Batavia, Illinois, USA

To suppress eddy currents, the Fermilab rapid cycling Booster synchrotron has no beam pipe; rather, its combined function dipoles are evacuated, exposing the beam directly to the magnet laminations. This arrangement significantly increases the resistive wall impedance of the dipoles and, in combination with the space charge impedance, substantially complicates longitudinal dynamics at transition. Voltage and accelerating phase profiles in the vicinity of transition are typically empirically optimized to minimize beam loss and emittance growth. In this contribution, we present results of experimental studies of beam acceleration near transition. Using comparisons between observed beam parameters and simulations, we obtain accurate calibrations for the RF program and extract quantitative information about parameters of relevance to the Booster laminated magnets longitudinal impedance model. The results are used to analyze transition crossing in the context of a future 50% increase in beam intensity planned for PIP-II, an upgrade of the Fermilab accelerating complex.

Poster MOPR033 [0.231 MB]

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MOPL002

The DESIR Facility at GANIL-SPIRAL2: The Transfer Beam Lines

quadrupole, ion, diagnostics, optics

179

L. Perrot, P. Blache, S. Rousselot
IPN, Orsay, France

Funding: French ANR, Investissements d'Avenir, EQUIPEX. Contract number ANR-11-EQPX-0012.
The new ISOL facility SPIRAL2 is currently being built at GANIL, Caen France. The commissioning of the accelerator is in progress since 2015. SPIRAL2 will produce a large number of new radioactive ion beams (RIB) at high intensities. In 2019, the DESIR facility will receive beams from the upgraded SPIRAL1 facility of GANIL (stable beam and target fragmentation), from the S3 Low Energy Branch (fusion-evaporation and deep-inelastic reactions). In order to deliver the RIB to the experimental set-ups installed in the DESIR hall, 110 meters of beam line are studied since 2014. This paper will focus on the recent studies which have been done on these transfer lines: beam optics and errors calculations, quadrupoles, diagnostics and mechanical designs.

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MOPL003

Status of the Beam Dynamics Design of the New Post-Stripper DTL for GSI - FAIR

DTL, quadrupole, simulation, ion

184

A. Rubin, D. Daehn, X. Du, L. Groening, M. Kaiser, S. Mickat
GSI, Darmstadt, Germany

The GSI UNILAC has served as injector for all ion species since 40 years. Its 10⁸ MHz Alvarez DTL providing acceleration from 1.4 MeV/u to 11.4 MeV/u has suffered from material fatigue and has to be replaced by a new section. The design of the new post-stripper DTL is now under development in GSI. An optimized drift tube shape increases the shunt impedance and varying stem orientations mitigate parasitic rf-modes. This contribution is on the beam dynamics layout.

Poster MOPL003 [2.176 MB]

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MOPL005

The Simulation Study of Beam Dynamics for CSNS Linac During Beam Commissioning

DTL, simulation, rfq, linac

192

Y. Yuan, H.F. Ji, S. Wang
IHEP, Beijing, People's Republic of China
J. Peng
CSNS, Guangdong Province, People's Republic of China

China Spallation Neutron Source (CSNS) is a high intensity accelerator based facility. Its accelerator consists of an H⁻ injector and a proton Rapid Cycling Synchrotron. The injector includes the front end and linac. The RFQ accelerates the beam to 3MeV, and then the Drift Tube Linac (DTL) accelerates it to 80MeV[1]. An Medium Energy Beam Transport (MEBT) matches RFQ and DTL, and the DTL consists of four tanks. Commissioning of the MEBT and the first DTL tank (DTL1) have been accomplished in the last run. Due to the difference of actual effective length and theoretical effective length of magnets in MEBT and DTL1, in order to compare its impact of beam transport, this paper takes a beam dynamics simulation on beam transport in MEBT and DTL1 with IMPACT-Z code[2]. Meanwhile, the transport of beam with different emittance in MEBT and DTL1 is studied because of the large emittance at RFQ exit. All the simulation includes magnet error and RF error.

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MOPL006

Beam Dynamics Study of C-Ads Injector-I With Developing P-Topo Code

rfq, simulation, space-charge, lattice

195

Zh.C. Liu, C. Li, Q. Qin, F. Yan, Y.L. Zhao
IHEP, Beijing, People's Republic of China

A parallelized, time-dependent 3D particle simulation code is under developing to study the high-intensity beam dynamics in linear accelerators. The self-consistent space charge effect is taken into account with the Particle-In-Cell (PIC) method. In this paper, the structure of program and the parallel strategy are demonstrated. Then, we show the results of code verification and benchmarking. It is proved that the solvers in P-TOPO code and parallel strategy are reliable and efficient. Finally, the beam dynamics simulation of C-ADS Injector-I at IHEP are launched with P-TOPO and other codes. The possible reasons for the differences between results given by separated codes are also proposed.

Poster MOPL006 [2.169 MB]

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MOPL009

Analytical Approach for Achromatic Structure Study and Design

quadrupole, dipole, cyclotron, factory

203

H.Y. Barminova
MEPhI, Moscow, Russia
A.S. Chikhachev
Allrussian Electrotechnical Institute, Moskow, Russia

The analytical approach is proposed to study the various achromatic structures. The method is based on the self-consistent time-dependent models, which allow to describe the dynamics of both continuous and bunched beam in external magnetic fields. The fully kinetic models are implemented in this approach. The kinetic distribution functions dependent on the motion integrals allow to obtain accurate Vlasov equation solutions as KV-model does it. The method allows to solve the envelope equation both analytically and by ODE system numerical integration, and to predict the beam phase portrait behavior in magnetic fields of the structure. The advantages of the method are the possibility of easy scaling and the wide physical generality, which is important for the multi-parameter problem of the high-intensity high-brightness beam formation. The results of the method application for the bending magnets and the quadrupoles are presented.

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MOPL017

High Power and High Duty Cycle Slit and Grid System for Hadron Accelerator Commissioning

simulation, scattering, rfq, DTL

226

B. Cheymol, A. Ponton
ESS, Lund, Sweden

Transverse emittance is one of the key measurements to be performed during the commissioning of the low energy sections of an hadron linac. The good knowledge of the beam transverse phase space allows a safe and efficient operation of the machines by using the results of the measurement for beam dynamic simulations. In this paper we will discuss the accuracy and the limits of the transverse emittance measurement performed with the slit-grid method based on the ESS beam parameters at the RFQ (beam energy equal to 3.62 MeV) and DTL tank 1 (beam energy equal to 21 MeV) output.

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TUAM3X01

Identification and Reduction of the CERN SPS Impedance

impedance, flattop, vacuum, simulation

260

E.N. Shaposhnikova, T. Argyropoulos, T. Bohl, A. Lasheen, J. Repond, H. Timko
CERN, Geneva, Switzerland

The first SPS impedance reduction programme has been completed in 2001, preparing the ring for its role as an injector of the LHC. This action has eliminated microwave instability on the SPS flat bottom and later nominal beam could be delivered to the LHC. The High Luminosity (HL-) LHC project is based on beam with twice higher intensity than the nominal one. One of the important SPS intensity limitations are longitudinal instabilities with minimum threshold reached on the 450 GeV flat top. In this paper the work which was carried on to identify the impedance sources driving these instabilities is described together with the next campaign of the SPS impedance reduction planned by the LHC Injector Upgrade (LIU) project. The present knowledge of the SPS transverse impedance is also presented.

Slides TUAM3X01 [6.457 MB]

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TUAM4X01

Electron Cloud in the CERN Accelerator Complex

operation, electron, simulation, quadrupole

266

G. Rumolo, H. Bartosik, E. Belli, G. Iadarola, K.S.B. Li, L. Mether, A. Romano
CERN, Geneva, Switzerland
M. Schenk
EPFL, Lausanne, Switzerland

Operation with closely spaced bunched beams causes the build up of an Electron Cloud (EC) in both the LHC and the two last synchrotrons of its injector chain (PS and SPS). Pressure rise and beam instabilities are observed at the PS during the last stage of preparation of the LHC beams. The SPS was affected by coherent and incoherent emittance growth along the LHC bunch train over many years, before scrubbing has finally suppressed the EC in a large fraction of the machine. When the LHC started regular operation with 50 ns beams in 2011, EC phenomena appeared in the arcs during the early phases, and in the interaction regions with two beams all along the run. Operation with 25 ns beams (late 2012 and 2015), which is nominal for LHC, has been hampered by EC induced high heat load in the cold arcs, bunch dependent emittance growth and degraded beam lifetime. Dedicated and parasitic machine scrubbing is presently the weapon used at the LHC to combat EC in this mode of operation. This talk summarises the EC experience in the CERN machines (PS, SPS, LHC) and highlight the dangers for future operation with more intense beams as well as the strategies to mitigate or suppress the effect.

Slides TUAM4X01 [9.785 MB]

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TUAM6X01

First Analysis of the Space Charge Effects on a Third Order Coupled Resonance

resonance, space-charge, synchrotron, simulation

278

G. Franchetti
GSI, Darmstadt, Germany
S.S. Gilardoni, A. Huschauer, F. Schmidt, R. Wasef
CERN, Geneva, Switzerland

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.

Slides TUAM6X01 [7.183 MB]

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TUPM3X01

R&D on Beam Injection and Bunching Schemes in the Fermilab Booster

booster, injection, linac, simulation

293

C.M. Bhat
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy
Fermilab is committed to upgrade its accelerator complex towards the intensity frontier by making a substantial increase in the average beam power delivered to the neutrino and muon programs pursuing HEP research in the lepton sector. Proton Improvement Plan (PIP) enables us to provide 700 kW beam power by the end of this year. By the middle of next decade, the foreseen PIP–II replaces the existing LINAC, a 400 MeV injector to the Booster, by an 800 MeV superconducting LINAC with beam power increased by >50%. In any case, the Fermilab Booster, an 8 GeV injector to the MI, is going to play a very significant role for the next two decades. In this context, we have recently developed an innovative beam injection scheme for the Booster called "early injection scheme" and put into operation. This novel scheme has a potential to increase the Booster beam intensity from the PIP design goal by ~40%. Some benefits of the scheme have already been seen so far. In this talk, I will present, principle of the scheme, results from beam experiments, current status and future plans for the early beam injection scheme. This scheme fits well with the current and future programs at Fermilab.
Author would like to thank S. Chaurize, C. Drennan, F. Garcia, B. Hendrick, W. Pellico, K. Seiya, T. Sullivan, K. Triplett and A. Waller,

Slides TUPM3X01 [7.081 MB]

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TUAM7Y11

High Current Uranium Beam Measurements at GSI-UNILAC for FAIR

brilliance, target, ion, proton

319

W.A. Barth, A. Adonin, Ch.E. Düllmann, M. Heilmann, R. Hollinger, E. Jäger, O.K. Kester, J. Khuyagbaatar, J. Krier, E. Plechov, P. Scharrer, W. Vinzenz, H. Vormann, A. Yakushev, S. Yaramyshev
GSI, Darmstadt, Germany
Ch.E. Düllmann, J. Khuyagbaatar, P. Scharrer, A. Yakushev
HIM, Mainz, Germany
Ch.E. Düllmann
Johannes Gutenberg University Mainz, Institut of Nuclear Chemistry, Mainz, Germany
P. Scharrer
Mainz University, Mainz, Germany
S. Yaramyshev
MEPhI, Moscow, Russia

In the context of an advanced machine investigation program supporting the ongoing UNILAC (Universal Linear Accelerator) upgrade program, a new uranium beam intensity record (10 emA, U²⁹⁺) at very high beam brilliance was achieved last year in a machine experiment campaign at GSI. The UNILAC as well as the heavy ion synchrotron SIS18 will serve as a high current heavy ion injector for the new FAIR (Facility for Antiproton and Ion Research) synchrotron SIS100. Results of the accomplished high current uranium beam measurements applying a newly developed pulsed hydrogen gas stripper (at 1.4'MeV/u) will be presented. The paper will focus on the evaluation and analysis of the measured beam brilliance and further implications to fulfil the FAIR heavy ion high intensity beam requirements.

Slides TUAM7Y11 [2.437 MB]

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TUPM2Y01

Beam Commissioning Results for the CSNS MEBT and DTL-1

DTL, rfq, linac, cavity

329

J. Peng, M.T. Li, X.H. Lu
CSNS, Guangdong Province, People's Republic of China
Y.W. An, S. Fu, L. Huang, M.Y. Huang, Y. Li, Z.P. Li, Y.D. Liu, S. Wang, S.Y. Xu, Y. Yuan
IHEP, Beijing, People's Republic of China

The China Spallation Neutron Source (CSNS) is designed to deliver a 1.6GeV proton beam to a solid metal target for neutron scattering research. It will be constructed in two phases. In the 1st phase, the beam power is designed to be 100kW. In the 2nd phase, the beam power will be upgraded to 500kW by doubling the linac output energy and beam current. The accelerator complex consists of a 50keV H⁻ ion source, a 3MeV Radio Frequency Quadrupole (RFQ), a 80MeV Drift tube Linac (DTL), and a 1.6GeV rapid-cycling synchrotron (RCS). Until March 2016, the front end and the first tank of DTL have been fully commissioned. The primary design goals of peak current, transverse emittance and beam energy have been achieved. This paper reports on the methods and the results of the commissioning.

Slides TUPM2Y01 [2.398 MB]

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TUPM4Y01

IFMIF-EVEDA RFQ, Measurement of Beam Input Conditions and Preparation to Beam Commissioning

rfq, simulation, solenoid, space-charge

338

M. Comunian, L. Bellan, E. Fagotti, A. Pisent
INFN/LNL, Legnaro (PD), Italy
L. Bellan
Univ. degli Studi di Padova, Padova, Italy

The commissioning phase of the IFMIF-EVEDA RFQ requires a complete beam characterization with simulations and measurements of the beam input from the IFMIF-EVEDA ion source and LEBT, in order to reach the RFQ input beam parameters. In this article the simulations of source LEBT RFQ will be reported with the corresponding set of measurements done on the Ion source and LEBT.

Slides TUPM4Y01 [7.230 MB]

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TUPM6Y01

Commissioning of C-ADS Injector I

rfq, cavity, solenoid, proton

348

J.S. Cao, H. Geng, R.L. Liu, C. Meng, Y.F. Sui, F. Yan, Q. Ye
IHEP, Beijing, People's Republic of China

As a test facility, the design goal of C-ADS Injector I is a 10mA, 10MeV CW proton linac, which uses a 3.2MeV normal conducting RFQ and superconducting single-spoke cavities for accelerating. The RF frequency of C-ADS Injector I accelerator is 325 MHz. In accordance to the progress of construction and considering the technical difficulties, the beam commissioning of C-ADS Injector I is carried out in 3 phases: Phase 1, with ECRIS + LEBT + RFQ + MEBT + TCM (two superconducting cavities), to reach 3.6 MeV; Phase 2, with ECRIS + LEBT + RFQ + MEBT + CM1 (seven superconducting cavities), to reach 5 MeV; Phase 3, with ECRIS + LEBT + RFQ + MEBT + CM¹⁺ CM2 (same as CM1), to finally achieve the design goal of C-ADS Injector I. This paper summarizes the beam commissioning in 3 phases and focusing on the third phase.

Slides TUPM6Y01 [3.617 MB]

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WEAM1X01

Code Bench-Marking for Long-Term Tracking and Adaptive Algorithms

space-charge, simulation, resonance, experiment

357

F. Schmidt, H. Bartosik, A. Huschauer, A. Oeftiger, M. Titze
CERN, Geneva, Switzerland
Y.I. Alexahin, J.F. Amundson, V.V. Kapin, E.G. Stern
Fermilab, Batavia, Illinois, USA
G. Franchetti
GSI, Darmstadt, Germany
J.A. Holmes
ORNL, Oak Ridge, Tennessee, USA

At CERN we have ramped up a program to investigate space charge effects in the LHC pre-injectors with high brightness beams and long storage times. This in view of the LIU upgrade project for these accelerators. These studies require massive simulation over large number of turns. To this end we have been looking at all available codes and started collaborations on code development with several laboratories: pyORBIT from SNS, SYNERGIA from Fermilab, MICROMAP from GSI and our in-house MAD-X code with an space charge upgrade. We have agreed with our collaborators to bench-mark all these codes in the framework of the GSI bench-marking suite, in particular the main types of frozen space charge and PIC codes are being tested. We also include a study on the subclass of purely frozen and the adaptive frozen modes both part of MAD-X in comparison with the purely frozen MICROMAP code. Last, we will report on CERN's code development effort to understand and eventually overcome the noise issue in PIC codes.
J. Coupard et al., ‘‘LHC Injectors Upgrade,
Technical Design Report, Vol. I: Protons'', LIU Technical Design
Report (TDR), CERN-ACC-2014-0337.

Slides WEAM1X01 [2.348 MB]

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WEAM5X01

Beam-Dynamics Issues in the FCC

luminosity, radiation, hadron, collider

373

F. Zimmermann, W. Bartmann, M. Benedikt, M.I. Besana, R. Bruce, O.S. Brüning, X. Buffat, F. Burkart, H. Burkhardt, S. Calatroni, F. Cerutti, S.D. Fartoukh, M. Fiascaris, C. Garion, B. Goddard, B.J. Holzer, W. Höfle, J.M. Jowett, R. Kersevan, R. Martin, L. Mether, A. Milanese, T. Pieloni, S. Redaelli, G. Rumolo, B. Salvant, M. Schaumann, D. Schulte, E.N. Shaposhnikova, L.S. Stoel, C. Tambasco, R. Tomás, D. Tommasini
CERN, Geneva, Switzerland
J.L. Abelleira, E. Cruz Alaniz, A. Seryi
JAI, Oxford, United Kingdom
R.B. Appleby
UMAN, Manchester, United Kingdom
P. Bambade, A. Faus-Golfe, J. Molson
LAL, Orsay, France
J. Barranco
EPFL, Lausanne, Switzerland
J.-L. Biarrotte, A. Lachaize
IPN, Orsay, France
O. Boine-Frankenheim, U. Niedermayer
TEMF, TU Darmstadt, Darmstadt, Germany
M. Boscolo, F. Collamati, A. Drago
INFN/LNF, Frascati (Roma), Italy
A. Chancé
CEA, Gif-sur-Yvette, France
B. Dalena, J. Payet
CEA/IRFU, Gif-sur-Yvette, France
J.D. Fox, G. Stupakov
SLAC, Menlo Park, California, USA
G. Guillermo Cantón
CINVESTAV, Mérida, Mexico
S. Khan, B. Riemann
DELTA, Dortmund, Germany
V. Kornilov
GSI, Darmstadt, Germany
T.M. Mitsuhashi, K. Ohmi
KEK, Ibaraki, Japan

Funding: European Commission under the Capacities 7th Framework Programme project EuCARD-2, grant agreement 312453, and the HORIZON 2020 project EuroCirCol, grant agreement 654305. Also by the German BMBF.
The international Future Circular Collider (FCC) study is designing hadron, lepton and lepton-hadron colliders based on a new 100 km tunnel in the Geneva region. The main focus and ultimate goal of the study are high-luminosity proton-proton collisions at a centre-of-mass energy of 100 TeV, using 16 T Nb3Sn dipole magnets. Specific FCC beam dynamics issues are related to the large circumference, the high brightness - made available by radiation damping -, the small geometric emittance, unprecedented collision energy and luminosity, the huge amount of energy stored in the beam, large synchrotron radiation power, plus the injection scenarios. In addition to the FCC-hh proper, also a High-Energy LHC (HE-LHC) is being explored, using the FCC-hh magnet technology in the existing LHC tunnel, which can yield a centre-of-mass energy around 25 TeV.

Slides WEAM5X01 [10.402 MB]

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WEAM6X01

Studies of High Intensity Proton FFAGs at RAL

injection, proton, linac, lattice

379

C.R. Prior
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The paper describes studies of high intensity proton accelerators for a next-generation source of short-pulse spallation neutrons. Along with conventional designs using rapid cycling synchrotrons, the long-term nature of the project provides scope for novel accelerator designs and developing technological ideas. A range of FFAG options is under consideration for the main spallation driver. Theory and simulation in the UK are combined with experimental studies of FFAGs in Japan, and a small prototype FFAG ring is planned to go on the FETS injector at RAL for essential R&D. The paper covers the broad scope of the programme and details the success of the study to date.

Slides WEAM6X01 [12.105 MB]

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WEPM1X01

Performance of Linac-4 Instrumentation During Commissioning

laser, linac, DTL, cavity

385

U. Raich
CERN, Geneva, Switzerland

Linac-4 is CERN’s new H⁻ Linac, which will replace the aging Linac-2 proton machine. Linac-4 is being built and commissioned in stages. While the machine is permanently equipped with the standard beam instrumentation necessary to ensure smooth operation, three dedicated measurement benches have also been designed to commission the source and LEBT at 45 keV, the MEBT and its chopper at 3 MeV as well as the first DTL tank at 12 MeV and finally the full DTL at 50 MeV and CCDTL at 100 MeV. The beam after the PIMS structures at the Linac’s full energy of 160 MeV will be sent to a beam dump and commissioned with permanently installed instruments. Installation and commissioning of the machine up to the CCDTL is now complete. This contribution will present the results from the various commissioning stages, showing the performance of the various diagnostic devices used and comparing the data obtained to simulations.

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WEPM7X01

The Application of the Optimization Algorithm in the Collimation System for CSNS/RCS

collimation, acceleration, space-charge, simulation

397

H.F. Ji, M.Y. Huang, Y. Jiao, N. Wang, S. Wang, S.Y. Xu
IHEP, Beijing, People's Republic of China

The robust conjugate direction search (RCDS) method, which is developed by X. Huang from the SLAC National Accelerator Laboratory, has high tolerance against noise in beam experiments and thus can find an optimal solution effectively and efficiently. In this paper, the RCDS method is used to optimize the beam collimation system for Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS). A two-stage beam collimation system was designed to localize the beam loss in the collimation section in CSNS/RCS. The parameters of secondary collimators are optimized with RCDS algorithm based on detailed tracking with the ORBIT program for a better performance of the collimation system. The study presents a way to quickly find an optimal parameter combination of the secondary collimators for a machine model for preparation for CSNS/RCS commissioning.

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WEPM1Y01

Emittance Reconstruction Techniques in Presence of Space Charge Applied During the Linac4 Beam Commissioning

linac, space-charge, diagnostics, DTL

433

V.A. Dimov, J.-B. Lallement, A.M. Lombardi
CERN, Geneva, Switzerland
R. Gaur
RRCAT, Indore, India

The classical emittance reconstruction technique, based on analytic calculations using transfer matrices and beam profile measurements, is reliable only if the emittance is conserved and the space charge forces are negligible in the beamline between the reconstruction and measurement points. The effects of space charge forces prevent this method from giving sound results up to a relativistic beta of about 0.5 and make it inapplicable to the Linac4 commissioning at 50 and 100 MeV. To compensate for this drawback we have developed a dedicated technique, the forward method, which extends the classical method by combining it with an iterative process of multiparticle tracking including space charge forces. The forward method, complemented with a tomographic reconstruction routine, has been applied to transverse and longitudinal emittance reconstruction during the Linac4 beam commissioning. In this paper we describe the reconstruction process and its application during Linac4 beam commissioning.

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WEPM8Y01

Simulation of Space-Charge Compensation of a Low-Energy Proton Beam in a Drift Section

simulation, electron, ion, proton

458

D. Noll, M. Droba, O. Meusel, U. Ratzinger, K. Schulte
IAP, Frankfurt am Main, Germany

Space-charge compensation provided by the accumulation of particles of opposing charge in the beam potential is an important effect occuring in magnetostatic low energy beam transport sections of high-intensity accelerators. An improved understanding of its effects might provide valuable input for the design of these beam lines. One approach to model the compensation process are Particle-in-Cell (PIC) simulations including residual gas ionisation. In simulations of a drifting proton beam, using the PIC code bender [1], some features of thermal equilibrium for the compensation electrons were found. This makes it possible to predict their spatial distribution using the Poisson-Boltzmann equation and thus the influence on beam transport. In this contribution, we will provide a comparison between the PIC simulations and the model as well as some ideas concerning the source of the (partial) thermalization.
[1] D. Noll, M. Droba, O. Meusel, U. Ratzinger, K. Schulte, C. Wiesner - The Particle-in-Cell Code Bender and Its Application to Non-Relativistic Beam Transport, WEO4LR02, Proc. of HB2014

Slides WEPM8Y01 [2.203 MB]

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THAM6X01

The Path to 1 MW: Beam Loss Control in the J-PARC 3-GeV RCS

injection, resonance, acceleration, power-supply

480

H. Hotchi, H. Harada, S. Kato, M. Kinsho, K. Okabe, P.K. Saha, Y. Shobuda, F. Tamura, N. Tani, Y. Watanabe, K. Yamamoto, M. Yamamoto, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The J-PARC 3-GeV RCS started 1-MW beam test from October 2014, and successfully achieved a 1-MW beam acceleration in January 2015. The most important issues in realizing such a high power routine beam operation are control and minimization of beam loss. This talk will present the recent progress of 1-MW beam tuning, especially focusing on our approaches to beam loss issues.

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THPM1X01

Typology of Space Charge Resonances

resonance, space-charge, lattice, focusing

486

I. Hofmann
GSI, Darmstadt, Germany

The existence of structural space charge resonant effects in otherwise linear periodic focusing systems is well-known, but referred to in a variety of languages and contexts. We show here that for short bunched beams a ‘‘classification'' in two major groups is possible, e.g. parametric resonances or instabilities on the one hand and single particle type space charge resonances on the other hand. The primary feature of distinction is that for the former the driving space charge force initially exists on the noise level (rms or higher order mismatch) only and gets amplified parametrically, hence an entirely coherent response; for the latter the driving space charge multipole is part of the initial density profile and the coherent response is weak. In the extreme limit of KV beams only parametric resonances (instabilities) exist, and in principle in all orders. For waterbag or Gaussian distributions we find half-integer parametric resonances only up to fourth order, but evidence for single particle resonances in all orders up to tenth have been identified.

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THPM4X01

Resonances and Envelope Instability in High Intensity Linear Accelerators

resonance, lattice, space-charge, linac

491

D. Jeon, J.-H. Jang, H. Jin
IBS, Daejeon, Republic of Korea

Funding: This work was supported by the Institute for Basic Science funded by the Ministry of Science, ICT and Future Planning (MSIP) and the NRF of Korea under Contract 2013M7A1A1075764.
Understanding of space charge effects has grown and recent studies have led to the findings of resonances of high intensity linear accelerators. Lately the sixth order resonance of high intensity linear accelerators was reported, along with the in-depth studies on the fourth order resonance and the envelope instability. Experiment studies on space charge resonances were reported. This paper reviews the resonances of high intensity linear accelerators such as the 4σ =360deg, and the 6σ =720deg resonances, along with the envelope instability.

Slides THPM4X01 [3.279 MB]

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THPM6X01

Space Charge Effects in FFAG

space-charge, closed-orbit, lattice, betatron

499

M. Haj Tahar, F. Méot
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Understanding space charge effects in FFAG is crucial in order to assess their potential for high power applications. This paper shows that, to carry out parametric studies of these effects in FFAG, the average field index of the focusing and defocusing magnets are the natural parametrization. Using several classes of particle distribution functions, we investigate the effects of space charge forces on the non-linear beam dynamics of FFAG and provide stability diagrams for an FFAG-like lattice. The method developed in this study is mainly applicable to systems with slowly varying parameters, i.e slow acceleration.

Slides THPM6X01 [2.171 MB]

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THPM9X01

Space Charge Effects and Mitigation in the CERN PS Booster, in View of the Upgrade

injection, booster, space-charge, simulation

517

E. Benedetto, M. Cieslak-Kowalska, V. Forte, F. Schmidt
CERN, Geneva, Switzerland
M. Cieslak-Kowalska
EPFL, Lausanne, Switzerland
V. Forte
Université Blaise Pascal, Clermont-Ferrand, France

The CERN PS Booster (PSB) is presently running with a space-charge tune spread larger than 0.5 at injection. Since the High Luminosity LHC (HL-LHC) will require beams with twice the intensity and brightness of today, the LHC Injector Upgrade (LIU) Project is putting in place an upgrade program for all the injector chain and, in particular, it relies on the important assumption that the PS Booster can successfully produce these beams after the implementation of the 160 MeV H⁻ injection from Linac4. This contribution describes the studies (measurements and simulations) that have been carried out to confirm that the PSB can indeed perform as needed in terms of beam brightness for the future HL-LHC runs. The importance of the mitigation measures already in place, such as the correction of the half-integer line, and the effects of non-linear resonances on the beam are also discussed.

Slides THPM9X01 [6.786 MB]

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THAM1Y01

Beam Commissioning of C-ADS Linac Instrumentation

linac, rfq, instrumentation, cavity

529

Y.F. Sui, J.S. Cao, J. He, H.Z. Ma, L. Wang, S.J. Wei, Q. Ye, L. Yu, J.H. Yue, X.Y. Zhao, Y. Zhao
IHEP, People's Republic of China

Funding: Work supported by China ADS Project (XDA03020000) and the National Natural Science Foundation of China (NO. 11205172, NO. 11475204).
The China Accelerator Driven Subcritical system (C-ADS) linac, which is composed of an ECR ion source, a low energy beam transport line (LEBT), a radio frequency quadrupole accelerator (RFQ), a medium energy beam transport line (MEBT) and cryomodules with SRF cavities to boost the energy up to 10 MeV. The injector linac will be equipped with beam diagnostics to measure the beam position, the transverse profile and emittance, the beam phase as well as beam current and beam losses. Though many are conventional design, They can provide efficient operation of drive linac. This paper gives an overview and detail in beam commissioning of C-ADS linac beam instrumentation.

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THAM5Y01

Path to Beam Loss Reduction in the SNS Linac Using Measurements, Simulation and Collimation

linac, optics, collimation, operation

548

A.V. Aleksandrov, A.P. Shishlo
ORNL, Oak Ridge, Tennessee, USA

Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
The SNS linac operation at its design average power currently is not limited by uncontrolled beam loss. However, further reduction of the beam loss remains an important aspect of the SNS linac tune up and operation. Even small “acceptable” beam loss leads to long term degradation of the accelerator equipment. The current state of model-based tuning at SNS leaves an unacceptably large residual beam loss level and has to be followed by an empirical, sometimes random, adjustment of many parameters to reduce the loss. This talk will discuss a set of coordinated efforts to develop tools for large dynamic range measurements, simulation and collimation in order to facilitate low loss linac tuning.

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THPM7Y01

A New RFQ Model and Symplectic Multi-Particle Tracking in the IMPACT Code Suite

rfq, space-charge, simulation, proton

562

J. Qiang
LBNL, Berkeley, California, USA
L. Li, Z. Wang
PKU, Beijing, People's Republic of China

The IMPACT code suite is a self-consistent parallel three-dimensional beam dynamics simulation toolbox that combines the magnetic optics method and the parallel particle-in-cell method. It has been widely used to study high intensity/high brightness beams in many accelerators. In this paper, we will report on recent improvements to the code such as the capability to model RFQ in time domain and symplectic multi-particle tracking with a gridless spectral solver for space-charge simulation.

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THPM9Y01

An Advanced Procedure for Longitudinal Beam Matching for SC CW Heavy Ion Linac With Variable Output Energy

cavity, linac, ion, acceleration

571

S. Yaramyshev, W.A. Barth, V. Gettmann, M. Heilmann, S. Mickat, M. Miski-Oglu
GSI, Darmstadt, Germany
K. Aulenbacher, W.A. Barth, V. Gettmann, S. Mickat, M. Miski-Oglu
HIM, Mainz, Germany
K. Aulenbacher
IKP, Mainz, Germany
W.A. Barth, S. Yaramyshev
MEPhI, Moscow, Russia
M. Heilmann
IAP, Frankfurt am Main, Germany

A multi-stage programm for the developmnet of a heavy ion superconducting (SC) continuous wave (CW) linac is in progress at HIM (Mainz, Germany), GSI (Darmstadt, Germany) and IAP (Frankfurt, Germany). The main beam acceleration is provided by up to nine multi-gap CH cavities. Due to variable beam energy, which coud be provided by each cavity separate, a longitudinal beam matching to each cavity is extremely important. The linac should provide the beam for physics experiments, smothly varying the output particle energy from 3.5 to 7.3 MeV/u, simultaneously keeping high beam quality. A dedicated algorythm for such a complicate matching, providing for the optimum machine settings (voltage and rf phase for each cavity), has been developed. The description of method and the obtained reasuts are discussed in this paper.

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