HB2016 - List of Keywords (injection)

Paper	Title	Other Keywords	Page
MOAM2P20	The LINAC4 Project	linac, emittance, cavity, DTL	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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MOAM4P40	A Fifteen Year Perspective on the Design and Performance of the SNS Accelerator	linac, target, electron, operation	9
	S.M. Cousineau ORNL, Oak Ridge, Tennessee, USA
	Commissioning of the Spallation Neutron Source accelerator began approximately fifteen years ago. Since this time, the accelerator has broken new technological ground with the operation of the world’s first superconducting H⁻ linac, the first liquid mercury target, and 1.4 MW of beam power. This talk will reflect on the issues and concerns that drove key decisions during the design phase, and will consider those decisions in the context of the actual performance of the accelerator. Noteworthy successes will be highlighted and lessons-learned will be discussed. Finally, a look forward toward the challenges associated with a higher power future at SNS will be presented.
	Slides MOAM4P40 [8.952 MB]
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MOAM6P60	Recent Progress of J-PARC MR Beam Commissioning and Operation	resonance, operation, proton, kicker	21
	S. Igarashi KEK, Ibaraki, Japan
	The main ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC) has been providing 30-GeV proton beams for elementary particle and nuclear physics experiments since 2009. The beam power of 390 kW has been recently achieved with 2·10¹⁴ protons per pulse and the cycle time of 2.48 s for the neutrino oscillation experiment. Main efforts in the beam tuning are to minimize beam losses and to localize the losses at the collimator section. Recent improvements include the 2nd harmonic rf operation to reduce the space charge effect with a larger bunching factor and corrections of resonances near the operation setting of the betatron tune. Because the beam bunches were longer with the 2nd harmonic rf operation, the injection kicker system was improved to accommodate the long bunches. We plan to achieve the target beam power of 750 kW in 2018 by making the cycle time faster to 1.3 s with new power supplies of main magnets, rf upgrade and improvement of injection and extraction devices. The possibility of the beam power beyond 750 kW is being explored with new settings of the betatron tune.
	Slides MOAM6P60 [9.968 MB]
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MOPR001	Figure-8 Storage Ring – Investigation of the Scaled Down Injection System	detector, simulation, experiment, kicker	41
	H. Niebuhr, A. Ates, M. Droba, O. Meusel, D. Noll, U. Ratzinger, J.F. Wagner IAP, Frankfurt am Main, Germany
	To store high current ion beams up to 10 A, a superconducting storage ring (F8SR) is planned at Frankfurt university. For the realisation, a scaled down experimental setup with normalconducting magnets is being build. Investigations of beam transport in solenoidal and toroidal guiding fields are in progress. At the moment, a new kind of injection system consisting of a solenoidal injection coil and a special vacuum vessel is under development. It is used to inject a hydrogen beam sideways between two toroidal magnets. In parallel operation, a second hydrogen beam is transported through both magnets to represent the circulating beam. In a second stage, an ExB-Kicker will be used as a septum to combine both beams into one. The current status of the experimental setup will be shown. For the design of the experiments, computer simulations using the 3D simulation code bender were performed. Different input parameters were checked to find the optimal injection and transport channel for the experiment. The results will be presented.
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MOPR002	Study on the Magnetic Measurement Results of the Injection System for CSNS/RCS	septum, power-supply, dipole, neutron	46
	M.Y. Huang, S. Fu, N. Huang, L. Huo, H.F. Ji, W. Kang, Y.Q. Liu, J. Peng, J. Qiu, L. Shen, S. Wang, X. Wu, S.Y. Xu, J. Zhang, G.Z. Zhou IHEP, Beijing, People's Republic of China
	Funding: Work supported by National Natural Science Foundation of China (11205185) A combination of the H⁻ stripping and phase space painting method is used to accumulate a high intensity beam in the Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS). The injection system for CSNS/RCS consists of three kinds of magnets: four direct current magnets (BC1-BC4), eight alternating current magnets (BH1-BH4 and BV1-BV4), two septum magnets (ISEP1 and ISEP2). In this paper, the magnetic measurements of the injection system were introduced and the data analysis was processed. The field uniformity and magnetizing curves of these magnets were given, and then the magnetizing fitting equations were obtained.
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MOPR004	H⁻ Charge Exchange Injection for XiPAF Synchrotron	proton, emittance, 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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MOPR006	Design of the 230MeV Proton Accelerator for Xi'an Proton Application Facility	proton, synchrotron, extraction, linac	55
	H.J. Yao, H.B. Chen, C. Cheng, C.T. Du, L. Du, T.B. Du, X. Guan, W.-H. Huang, H. Jiang, G.R. Li, C.-X. Tang, R. Tang, D. Wang, W. Wang, X.W. Wang, L. Wu, Q.Z. Xing, Y. Yang, Z. Yang, H.J. Zeng, H.Y. Zhang, Q. Zhang, Q.Z. Zhang, S.X. Zheng TUB, Beijing, People's Republic of China W. Chen NINT, Xi'an, People's Republic of China W.Q. Guan, Y. He, J. Li NUCTECH, Beijing, People's Republic of China S.-Y. Lee Indiana University, Bloomington, Indiana, USA M.T. Qiu, B.C. Wang, Y.P. Wang, Z.M. Wang, Y.H. Yan, H.Z. Zhang, C. Zhao State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, Shannxi, People's Republic of China
	We report a design of the 230 MeV proton accelera-tor, the Xi’an Proton Application Facility (XiPAF), which will be located in Xi’an city, China. The facility will provide proton beam with the maximum energy of 230 MeV for the research of the single event effect. The facility, composed of a 230 MeV synchrotron, a 7 MeV H⁻ linac injector and two experimental stations, will provide a flux of 10⁵~10⁸ p/cm²/s with the uni-formity of better than 90% on the 10 cm×10 cm sample.
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MOPR012	The New HL-LHC Injection and Transport Protection System	simulation, kicker, brightness, proton	81
	F.M. Velotti, W. Bartmann, C. Bracco, M.A. Fraser, B. Goddard, V. Kain, A. Lechner, M. Meddahi CERN, Geneva, Switzerland
	The High-Luminosity LHC (HL-LHC) upgrade represents a challenge for the full chain of its injectors. The aim is to provide beams with a brightness a factor of two higher than the present maximum achieved. The 450 GeV beams injected into the LHC are directly provided by the Super Proton Synchrotron (SPS) via two transfer lines (TL), TI2 and TI8. Such transfer lines are both equipped with a passive protection system to protect the LHC aperture against ultra-fast failures of the extraction and transport systems. In the LHC instead, the injection protection system protects the cold apertures against possible failures of the injection kicker, MKI. Due to the increase of the beam brightness, these passive systems need to be upgraded. In this paper, the foreseen and ongoing modifications of the LHC injection protection system and the TL collimators are presented. Simulations of the protection guaranteed by the new systems in case of failures are described, together with benchmark with measurements for the current systems.
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MOPR020	Space Charge Effects of High Intensity Beams at BRing	resonance, emittance, simulation, 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	emittance, linac, 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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MOPR026	Space Charge Mitigation With Longitudinally Hollow Bunches	space-charge, synchrotron, resonance, emittance	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	emittance, space-charge, 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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MOPL010	ESSnuSB Project to Produce Intense Beams of Neutrinos and Muons	proton, target, linac, detector	207
	E. Bouquerel IPHC, Strasbourg Cedex 2, France
	Funding: This project is now supported by the COST Action CA15139 "Combining forces for a novel European facility for neutrino-antineutrino symmetry-violation discovery" (EuroNuNet). A new project for the production of a very intense neutrino beam has arisen to enable the discovery of a leptonic CP violation. This facility will use the world’s most intense pulsed spallation neutron source, the European Spallation Source (ESS) under construction in Lund. Its linac is expected to be fully operational at 5 MW power by 2023, using 2 GeV protons. In addition to the neutrinos, the ESSnuSB proposed facility will produce a copious number of muons at the same time. These muons could be used by a future Neutrino Factory to study a possible CP violation in the leptonic sector and neutrino cross-sections. They could also be used by a muon collider or a low energy nuSTORM. The layout of such a facility, consisting in the upgrade of the linac, the use of an accumulator ring, a target/horn system and a megaton Water Cherenkov neutrino detector, is presented. The physics potential is also described.
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MOPL011	Laser Stripping H⁻ Charge Exchange Injection by Femtosecond Lasers	laser, resonance, proton, optics	212
	T.V. Gorlov ORNL, Oak Ridge, Tennessee, USA
	A new method for H⁻ laser assistant charge exchange injection using femtosecond laser pulses is considered. The existing method uses a divergent laser beam that allows compensation of angular and momentum spread of the stripped beam. The femtosecond laser pulse has a similar property that can compensate the spread and yield efficient laser stripping. Results of simulations with realistic femtosecond laser and H⁻ beam parameters are discussed. The proposed method may have some benefit for particular technical conditions compared with others.
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MOPL020	Online Measurement of the Energy Spread of Multi-Turn Beam in the Fermilab Booster at Injection	booster, linac, software, kicker	237
	C.M. Bhat, B. Hendricks Fermilab, Batavia, Illinois, USA J.J. Nelson Brown University, Providence, USA
	Funding: Work supported by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy Abstract: We have developed a computer program interfaced with the ACNET environment for Fermilab accelerators to measure energy spread of the proton beam from the LINAC at an injection kinetic energy of 400 MeV. It uses a digitizing oscilloscope and provides the user the ability to configure scope settings for optimal data acquisition from a resistive wall monitor. When the program is launched, it secures complete control of the scope. Subsequently, a special “one-shot” timeline is generated to initiate the beam injection into the Booster. After the completion of the beam injection from the LINAC, a gap of about 40 ns is produced in the Booster beam using a set of kickers and line-charge distribution data is collected for next 200 μs. The program then analyzes the data to extract the gap width, beam revolution period and beam energy spread. We illustrate a case with an example. We also present results on beam energy spread as a function of beam intensity from a recent measurement. Author would like to thank S. Chaurize, C. Drennan, W. Pellico, K. Seiya, T. Sullivan and K. Triplett
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MOPL024	Study of Magnets Sorting of the CSNS/RCS Dipoles and Quadrupoles*	dipole, quadrupole, closed-orbit, lattice	247
	Y.W. An, H.F. Ji, Y. Li, S. Wang, S.Y. Xu IHEP, Beijing, People's Republic of China J. Peng CSNS, Guangdong Province, People's Republic of China
	Funding: Work supported by National Natural Science Foundation of China (11405189)* The Rapid Cycling Synchrotron plays an important role in the China Spallation Neutron Source. RCS accumulates and accelerates the proton beams from 80MeV to 1.6GeV for striking the target with the repetition rate of 25Hz. RCS demands low uncontrolled loss for hands on maintenance, and one needs a tight tolerance on magnet field accuracy. Magnet sorting can be done to minimize linear effects of beam dynamics. Using closed-orbit distortion (COD) and beta-beating independently as the merit function, and considering maintaining the symmetry of the lattice, a code based on traversal algorithm is developed to get the dipoles and quadrupoles sorting for CSNS/RCS. The comparison of beam distribution, collimation efficiency and beam loss are also investigated according to beam injection and beam accelerating.
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TUAM2X01	Measurement and Interpretation of Transverse Beam Instabilities in the CERN Large Hadron Collider (LHC) and Extrapolations to HL-LHC	octupole, coupling, simulation, electron	254
	E. Métral, G. Arduini, N. Biancacci, X. Buffat, L.R. Carver, G. Iadarola, K.S.B. Li, T. Pieloni, A. Romano, G. Rumolo, B. Salvant, M. Schenk, C. Tambasco CERN, Geneva, Switzerland J. Barranco EPFL, Lausanne, Switzerland
	Since the first transverse instability observed in 2010, many studies have been performed on both measurement and simulation sides and several lessons have been learned. In a machine like the LHC, not only all the mechanisms have to be understood separately, but the possible interplays between the different phenomena need to be analyzed in detail, including the beam-coupling impedance (with in particular all the necessary collimators to protect the machine but also new equipment such as crab cavities for HL-LHC), linear and nonlinear chromaticity, Landau octupoles (and other intrinsic nonlinearities), transverse damper, space charge, beam-beam (long-range and head-on), electron cloud, linear coupling strength, tune separation between the transverse planes, tune split between the two beams, transverse beam separation between the two beams, etc. This paper reviews all the transverse beam instabilities observed and simulated so far, the mitigation measures which have been put in place, the remaining questions and challenges and some recommendations for the future.
	Slides TUAM2X01 [36.385 MB]
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TUAM5X01	Space Charge Driven Beam Loss for Cooled Beams and Mitigation Measures in the CERN Low Energy Ion Ring	resonance, ion, space-charge, sextupole	272
	H. Bartosik, S. Hancock, A. Huschauer, V. Kain CERN, Geneva, Switzerland
	The performance of the CERN Low Energy Ion Ring (LEIR) with electron cooled lead ion beams is presently limited by losses, which occur during RF capture and the first part of acceleration. Extensive experimental studies performed in 2015 indicate that the losses are caused by the interplay of betatron resonances and the direct space charge detuning, which is significantly enhanced during bunching. Mitigation measures have already been identified and successfully tested, such as reducing the peak line charge density after RF capture, i.e. increasing the rms longitudinal emittance, and compensating third order resonances using existing harmonic sextupole correctors. New record intensities at extraction have been achieved. This talk describes the main experimental results from the 2015 measurement campaign including already implemented mitigation measures and the proposed strategy for even further increasing the LEIR intensity reach in the future.
	Slides TUAM5X01 [8.803 MB]
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TUPM3X01	R&D on Beam Injection and Bunching Schemes in the Fermilab Booster	booster, emittance, 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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TUPM5X01	Injection Painting Improvements in the J-PARC RCS	power-supply, controls, target, feedback	299
	S. Kato, K. Horino, H. Hotchi, M. Kinsho, K. Okabe, P.K. Saha, Y. Shobuda, T. Takayanagi, T. Tobita, T. Ueno JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan H. Harada JAEA, Ibaraki-ken, Japan
	In the J-PARC 3GeV RCS, the injection painting is essential method for the reduction of the space charge force. In this method, the H⁻ beam from Linac is arranged on the large phase space area of the ring orbit during multiple turns. To implement this method, painting magnets form the time variable beam orbit. Therefore, the precise output current control of the magnet power supply is required. Because the power supply controlled by mainly feedforward signal is operated, we developed the iterative tuning method for the optimum feedforward parameter determination. As a result, we could reduce the tracking error of the current compared to before. Furthermore, to improve the accuracy of the painting area size, we applied the output readjustment additionally. Because the current monitor value of the power supply was different from the actual magnetic field due to the delay in the circuit and the leakage field, we corrected the tracking of the current based on the measured painting area size determined by the analysis of the measured COD. As a result, we achieved the precise injection painting. This talk presents these improvement results of the injection painting in the RCS.
	Slides TUPM5X01 [4.122 MB]
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TUPM6X01	H⁻ Charge Exchange Injection Issues at High Power	electron, proton, target, vacuum	304
	M.A. Plum ORNL, Oak Ridge, Tennessee, USA
	At low beam powers H− charge exchange injection into a storage ring or synchrotron is relatively simple. A thin stripper foil removes the two “convoy” electrons from the H− particle and the newly-created proton begins to circulate around the ring. At high beam powers there are complications due to the heat created in the stripper foil, the power in the H⁰ excited states, and the power in the convoy electrons. The charge-exchanged beam power at the Oak Ridge Spallation Neutron Source is the highest in the world. Although the SNS ring was carefully designed to operate at this level there have been surprises, primarily involving the convoy electrons. Examples include damage to the foil brackets due to reflected convoy electrons and damage to the electron collector due to the primary convoy electrons. The SNS Second Target Station project calls for doubling the beam power and thus placing even more stress on the charge-exchange-injection beam-line components. In this presentation we will compare charge-exchange-injection designs at high-power facilities around the world, discuss lessons learned, and describe the future plans at SNS.
	Slides TUPM6X01 [10.929 MB]
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TUPM7X01	An Experimental Plan for 400 MeV H⁻ Stripping to Proton by Using Only Lasers in the J-PARC RCS	laser, proton, experiment, operation	310
	P.K. Saha, H. Harada, S. Kato, M. Kinsho JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Y. Irie, I. Yamane KEK, Ibaraki, Japan
	The 3-GeV RCS (Rapid Cycling Synchrotron) of J-PARC is gradually approaching to the design operation with 1 MW beam power. Studies are ongoing for further higher beam power of 1.5 MW. The injection and extraction energy of RCS is 0.4 and 3 GeV, respectively. Lifetime of the stripper foil is the highest concern beyond 1 MW beam power. We have also already started detail studies of H⁻ stripping to protons by using lasers. However, in order to avoid high magnetic field required in the process of laser-assisted H⁻ stripping to protons, especially for lower H⁻ energies, we are studying the possibilities of using only laser system for 400 MeV H⁻ beam in the RCS. The method is a three step process, similar to that of SNS but lasers are used instead of high field magnets in the 1st (H⁻ to H⁰) and 3rd step (H0* to p). A Nd:YAG laser can be properly used for both 1st and 3rd steps, where commercially available powerful Excimer laser will be used an H⁰ excitation in the 2nd step. Although detail R&D studies are necessary to reach to the ultimate goal, we plan to carry out an experiment in 2017. A detail of the present method, experimental schedule and the expected outcome will be presented.
	Slides TUPM7X01 [3.316 MB]
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TUPM3Y01	Operational Experience and Future Plans at ISIS	operation, acceleration, proton, simulation	333
	D.J. Adams STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom I.S.K. Gardner, B. Jones, A.H. Kershaw, A.P. Letchford, R.J. Mathieson, A. Pertica, B.G. Pine, A. Seville, H. V. Smith, C.M. Warsop, R.E. Williamson, M. Wright STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The ISIS spallation neutron and muon source has been in operation since 1984. The accelerator complex consists of an H⁻ ion source, 665 keV RFQ, 70 MeV linac, 800 MeV proton synchrotron and associated beam transfer lines. The facility currently delivers ~2.8·10¹³ protons per pulse (ppp) at 50 Hz, which is shared between two target stations. High intensity performance and operation are dominated by the need to minimise and control beam loss, which is key to sustainable machine operation, allowing essential hands on maintenance. The facility has had several upgrades including an RFQ, ring Second Harmonic RF system, key developments of diagnostics and instrumentation required for improving beam control and a Second Target station. Upgrades being installed, or expected in the near future, include: a ring damping system, a new injector MEBT with fast injection chopper and an upgraded 50 Hz target. Operational experience of ISIS and the impacts of its past and future upgrades are discussed. Ideas for major upgrades to ISIS are briefly reviewed, as are the underlying R&D projects.
	Slides TUPM3Y01 [2.902 MB]
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WEAM6X01	Studies of High Intensity Proton FFAGs at RAL	proton, linac, emittance, 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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THAM6X01	The Path to 1 MW: Beam Loss Control in the J-PARC 3-GeV RCS	resonance, emittance, 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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THPM9X01	Space Charge Effects and Mitigation in the CERN PS Booster, in View of the Upgrade	emittance, 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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Paper

Title

Other Keywords

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MOAM2P20

The LINAC4 Project

linac, emittance, cavity, DTL

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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MOAM4P40

A Fifteen Year Perspective on the Design and Performance of the SNS Accelerator

linac, target, electron, operation

9

S.M. Cousineau
ORNL, Oak Ridge, Tennessee, USA

Commissioning of the Spallation Neutron Source accelerator began approximately fifteen years ago. Since this time, the accelerator has broken new technological ground with the operation of the world’s first superconducting H⁻ linac, the first liquid mercury target, and 1.4 MW of beam power. This talk will reflect on the issues and concerns that drove key decisions during the design phase, and will consider those decisions in the context of the actual performance of the accelerator. Noteworthy successes will be highlighted and lessons-learned will be discussed. Finally, a look forward toward the challenges associated with a higher power future at SNS will be presented.

Slides MOAM4P40 [8.952 MB]

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MOAM6P60

Recent Progress of J-PARC MR Beam Commissioning and Operation

resonance, operation, proton, kicker

21

S. Igarashi
KEK, Ibaraki, Japan

The main ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC) has been providing 30-GeV proton beams for elementary particle and nuclear physics experiments since 2009. The beam power of 390 kW has been recently achieved with 2·10¹⁴ protons per pulse and the cycle time of 2.48 s for the neutrino oscillation experiment. Main efforts in the beam tuning are to minimize beam losses and to localize the losses at the collimator section. Recent improvements include the 2nd harmonic rf operation to reduce the space charge effect with a larger bunching factor and corrections of resonances near the operation setting of the betatron tune. Because the beam bunches were longer with the 2nd harmonic rf operation, the injection kicker system was improved to accommodate the long bunches. We plan to achieve the target beam power of 750 kW in 2018 by making the cycle time faster to 1.3 s with new power supplies of main magnets, rf upgrade and improvement of injection and extraction devices. The possibility of the beam power beyond 750 kW is being explored with new settings of the betatron tune.

Slides MOAM6P60 [9.968 MB]

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MOPR001

Figure-8 Storage Ring – Investigation of the Scaled Down Injection System

detector, simulation, experiment, kicker

41

H. Niebuhr, A. Ates, M. Droba, O. Meusel, D. Noll, U. Ratzinger, J.F. Wagner
IAP, Frankfurt am Main, Germany

To store high current ion beams up to 10 A, a superconducting storage ring (F8SR) is planned at Frankfurt university. For the realisation, a scaled down experimental setup with normalconducting magnets is being build. Investigations of beam transport in solenoidal and toroidal guiding fields are in progress. At the moment, a new kind of injection system consisting of a solenoidal injection coil and a special vacuum vessel is under development. It is used to inject a hydrogen beam sideways between two toroidal magnets. In parallel operation, a second hydrogen beam is transported through both magnets to represent the circulating beam. In a second stage, an ExB-Kicker will be used as a septum to combine both beams into one. The current status of the experimental setup will be shown. For the design of the experiments, computer simulations using the 3D simulation code bender were performed. Different input parameters were checked to find the optimal injection and transport channel for the experiment. The results will be presented.

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MOPR002

Study on the Magnetic Measurement Results of the Injection System for CSNS/RCS

septum, power-supply, dipole, neutron

46

M.Y. Huang, S. Fu, N. Huang, L. Huo, H.F. Ji, W. Kang, Y.Q. Liu, J. Peng, J. Qiu, L. Shen, S. Wang, X. Wu, S.Y. Xu, J. Zhang, G.Z. Zhou
IHEP, Beijing, People's Republic of China

Funding: Work supported by National Natural Science Foundation of China (11205185)
A combination of the H⁻ stripping and phase space painting method is used to accumulate a high intensity beam in the Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS). The injection system for CSNS/RCS consists of three kinds of magnets: four direct current magnets (BC1-BC4), eight alternating current magnets (BH1-BH4 and BV1-BV4), two septum magnets (ISEP1 and ISEP2). In this paper, the magnetic measurements of the injection system were introduced and the data analysis was processed. The field uniformity and magnetizing curves of these magnets were given, and then the magnetizing fitting equations were obtained.

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MOPR004

H⁻ Charge Exchange Injection for XiPAF Synchrotron

proton, emittance, 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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MOPR006

Design of the 230MeV Proton Accelerator for Xi'an Proton Application Facility

proton, synchrotron, extraction, linac

55

H.J. Yao, H.B. Chen, C. Cheng, C.T. Du, L. Du, T.B. Du, X. Guan, W.-H. Huang, H. Jiang, G.R. Li, C.-X. Tang, R. Tang, D. Wang, W. Wang, X.W. Wang, L. Wu, Q.Z. Xing, Y. Yang, Z. Yang, H.J. Zeng, H.Y. Zhang, Q. Zhang, Q.Z. Zhang, S.X. Zheng
TUB, Beijing, People's Republic of China
W. Chen
NINT, Xi'an, People's Republic of China
W.Q. Guan, Y. He, J. Li
NUCTECH, Beijing, People's Republic of China
S.-Y. Lee
Indiana University, Bloomington, Indiana, USA
M.T. Qiu, B.C. Wang, Y.P. Wang, Z.M. Wang, Y.H. Yan, H.Z. Zhang, C. Zhao
State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, Shannxi, People's Republic of China

We report a design of the 230 MeV proton accelera-tor, the Xi’an Proton Application Facility (XiPAF), which will be located in Xi’an city, China. The facility will provide proton beam with the maximum energy of 230 MeV for the research of the single event effect. The facility, composed of a 230 MeV synchrotron, a 7 MeV H⁻ linac injector and two experimental stations, will provide a flux of 10⁵~10⁸ p/cm²/s with the uni-formity of better than 90% on the 10 cm×10 cm sample.

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MOPR012

The New HL-LHC Injection and Transport Protection System

simulation, kicker, brightness, proton

81

F.M. Velotti, W. Bartmann, C. Bracco, M.A. Fraser, B. Goddard, V. Kain, A. Lechner, M. Meddahi
CERN, Geneva, Switzerland

The High-Luminosity LHC (HL-LHC) upgrade represents a challenge for the full chain of its injectors. The aim is to provide beams with a brightness a factor of two higher than the present maximum achieved. The 450 GeV beams injected into the LHC are directly provided by the Super Proton Synchrotron (SPS) via two transfer lines (TL), TI2 and TI8. Such transfer lines are both equipped with a passive protection system to protect the LHC aperture against ultra-fast failures of the extraction and transport systems. In the LHC instead, the injection protection system protects the cold apertures against possible failures of the injection kicker, MKI. Due to the increase of the beam brightness, these passive systems need to be upgraded. In this paper, the foreseen and ongoing modifications of the LHC injection protection system and the TL collimators are presented. Simulations of the protection guaranteed by the new systems in case of failures are described, together with benchmark with measurements for the current systems.

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MOPR020

Space Charge Effects of High Intensity Beams at BRing

resonance, emittance, simulation, 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

emittance, linac, 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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MOPR026

Space Charge Mitigation With Longitudinally Hollow Bunches

space-charge, synchrotron, resonance, emittance

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

emittance, space-charge, 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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MOPL010

ESSnuSB Project to Produce Intense Beams of Neutrinos and Muons

proton, target, linac, detector

207

E. Bouquerel
IPHC, Strasbourg Cedex 2, France

Funding: This project is now supported by the COST Action CA15139 "Combining forces for a novel European facility for neutrino-antineutrino symmetry-violation discovery" (EuroNuNet).
A new project for the production of a very intense neutrino beam has arisen to enable the discovery of a leptonic CP violation. This facility will use the world’s most intense pulsed spallation neutron source, the European Spallation Source (ESS) under construction in Lund. Its linac is expected to be fully operational at 5 MW power by 2023, using 2 GeV protons. In addition to the neutrinos, the ESSnuSB proposed facility will produce a copious number of muons at the same time. These muons could be used by a future Neutrino Factory to study a possible CP violation in the leptonic sector and neutrino cross-sections. They could also be used by a muon collider or a low energy nuSTORM. The layout of such a facility, consisting in the upgrade of the linac, the use of an accumulator ring, a target/horn system and a megaton Water Cherenkov neutrino detector, is presented. The physics potential is also described.

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MOPL011

Laser Stripping H⁻ Charge Exchange Injection by Femtosecond Lasers

laser, resonance, proton, optics

212

T.V. Gorlov
ORNL, Oak Ridge, Tennessee, USA

A new method for H⁻ laser assistant charge exchange injection using femtosecond laser pulses is considered. The existing method uses a divergent laser beam that allows compensation of angular and momentum spread of the stripped beam. The femtosecond laser pulse has a similar property that can compensate the spread and yield efficient laser stripping. Results of simulations with realistic femtosecond laser and H⁻ beam parameters are discussed. The proposed method may have some benefit for particular technical conditions compared with others.

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MOPL020

Online Measurement of the Energy Spread of Multi-Turn Beam in the Fermilab Booster at Injection

booster, linac, software, kicker

237

C.M. Bhat, B. Hendricks
Fermilab, Batavia, Illinois, USA
J.J. Nelson
Brown University, Providence, USA

Funding: Work supported by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy
Abstract: We have developed a computer program interfaced with the ACNET environment for Fermilab accelerators to measure energy spread of the proton beam from the LINAC at an injection kinetic energy of 400 MeV. It uses a digitizing oscilloscope and provides the user the ability to configure scope settings for optimal data acquisition from a resistive wall monitor. When the program is launched, it secures complete control of the scope. Subsequently, a special “one-shot” timeline is generated to initiate the beam injection into the Booster. After the completion of the beam injection from the LINAC, a gap of about 40 ns is produced in the Booster beam using a set of kickers and line-charge distribution data is collected for next 200 μs. The program then analyzes the data to extract the gap width, beam revolution period and beam energy spread. We illustrate a case with an example. We also present results on beam energy spread as a function of beam intensity from a recent measurement.
Author would like to thank S. Chaurize, C. Drennan, W. Pellico, K. Seiya, T. Sullivan and K. Triplett

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MOPL024

Study of Magnets Sorting of the CSNS/RCS Dipoles and Quadrupoles*

dipole, quadrupole, closed-orbit, lattice

247

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

Funding: Work supported by National Natural Science Foundation of China (11405189)*
The Rapid Cycling Synchrotron plays an important role in the China Spallation Neutron Source. RCS accumulates and accelerates the proton beams from 80MeV to 1.6GeV for striking the target with the repetition rate of 25Hz. RCS demands low uncontrolled loss for hands on maintenance, and one needs a tight tolerance on magnet field accuracy. Magnet sorting can be done to minimize linear effects of beam dynamics. Using closed-orbit distortion (COD) and beta-beating independently as the merit function, and considering maintaining the symmetry of the lattice, a code based on traversal algorithm is developed to get the dipoles and quadrupoles sorting for CSNS/RCS. The comparison of beam distribution, collimation efficiency and beam loss are also investigated according to beam injection and beam accelerating.

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TUAM2X01

Measurement and Interpretation of Transverse Beam Instabilities in the CERN Large Hadron Collider (LHC) and Extrapolations to HL-LHC

octupole, coupling, simulation, electron

254

E. Métral, G. Arduini, N. Biancacci, X. Buffat, L.R. Carver, G. Iadarola, K.S.B. Li, T. Pieloni, A. Romano, G. Rumolo, B. Salvant, M. Schenk, C. Tambasco
CERN, Geneva, Switzerland
J. Barranco
EPFL, Lausanne, Switzerland

Since the first transverse instability observed in 2010, many studies have been performed on both measurement and simulation sides and several lessons have been learned. In a machine like the LHC, not only all the mechanisms have to be understood separately, but the possible interplays between the different phenomena need to be analyzed in detail, including the beam-coupling impedance (with in particular all the necessary collimators to protect the machine but also new equipment such as crab cavities for HL-LHC), linear and nonlinear chromaticity, Landau octupoles (and other intrinsic nonlinearities), transverse damper, space charge, beam-beam (long-range and head-on), electron cloud, linear coupling strength, tune separation between the transverse planes, tune split between the two beams, transverse beam separation between the two beams, etc. This paper reviews all the transverse beam instabilities observed and simulated so far, the mitigation measures which have been put in place, the remaining questions and challenges and some recommendations for the future.

Slides TUAM2X01 [36.385 MB]

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TUAM5X01

Space Charge Driven Beam Loss for Cooled Beams and Mitigation Measures in the CERN Low Energy Ion Ring

resonance, ion, space-charge, sextupole

272

H. Bartosik, S. Hancock, A. Huschauer, V. Kain
CERN, Geneva, Switzerland

The performance of the CERN Low Energy Ion Ring (LEIR) with electron cooled lead ion beams is presently limited by losses, which occur during RF capture and the first part of acceleration. Extensive experimental studies performed in 2015 indicate that the losses are caused by the interplay of betatron resonances and the direct space charge detuning, which is significantly enhanced during bunching. Mitigation measures have already been identified and successfully tested, such as reducing the peak line charge density after RF capture, i.e. increasing the rms longitudinal emittance, and compensating third order resonances using existing harmonic sextupole correctors. New record intensities at extraction have been achieved. This talk describes the main experimental results from the 2015 measurement campaign including already implemented mitigation measures and the proposed strategy for even further increasing the LEIR intensity reach in the future.

Slides TUAM5X01 [8.803 MB]

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TUPM3X01

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

booster, emittance, 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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TUPM5X01

Injection Painting Improvements in the J-PARC RCS

power-supply, controls, target, feedback

299

S. Kato, K. Horino, H. Hotchi, M. Kinsho, K. Okabe, P.K. Saha, Y. Shobuda, T. Takayanagi, T. Tobita, T. Ueno
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
H. Harada
JAEA, Ibaraki-ken, Japan

In the J-PARC 3GeV RCS, the injection painting is essential method for the reduction of the space charge force. In this method, the H⁻ beam from Linac is arranged on the large phase space area of the ring orbit during multiple turns. To implement this method, painting magnets form the time variable beam orbit. Therefore, the precise output current control of the magnet power supply is required. Because the power supply controlled by mainly feedforward signal is operated, we developed the iterative tuning method for the optimum feedforward parameter determination. As a result, we could reduce the tracking error of the current compared to before. Furthermore, to improve the accuracy of the painting area size, we applied the output readjustment additionally. Because the current monitor value of the power supply was different from the actual magnetic field due to the delay in the circuit and the leakage field, we corrected the tracking of the current based on the measured painting area size determined by the analysis of the measured COD. As a result, we achieved the precise injection painting. This talk presents these improvement results of the injection painting in the RCS.

Slides TUPM5X01 [4.122 MB]

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TUPM6X01

H⁻ Charge Exchange Injection Issues at High Power

electron, proton, target, vacuum

304

M.A. Plum
ORNL, Oak Ridge, Tennessee, USA

At low beam powers H− charge exchange injection into a storage ring or synchrotron is relatively simple. A thin stripper foil removes the two “convoy” electrons from the H− particle and the newly-created proton begins to circulate around the ring. At high beam powers there are complications due to the heat created in the stripper foil, the power in the H⁰ excited states, and the power in the convoy electrons. The charge-exchanged beam power at the Oak Ridge Spallation Neutron Source is the highest in the world. Although the SNS ring was carefully designed to operate at this level there have been surprises, primarily involving the convoy electrons. Examples include damage to the foil brackets due to reflected convoy electrons and damage to the electron collector due to the primary convoy electrons. The SNS Second Target Station project calls for doubling the beam power and thus placing even more stress on the charge-exchange-injection beam-line components. In this presentation we will compare charge-exchange-injection designs at high-power facilities around the world, discuss lessons learned, and describe the future plans at SNS.

Slides TUPM6X01 [10.929 MB]

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TUPM7X01

An Experimental Plan for 400 MeV H⁻ Stripping to Proton by Using Only Lasers in the J-PARC RCS

laser, proton, experiment, operation

310

P.K. Saha, H. Harada, S. Kato, M. Kinsho
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Irie, I. Yamane
KEK, Ibaraki, Japan

The 3-GeV RCS (Rapid Cycling Synchrotron) of J-PARC is gradually approaching to the design operation with 1 MW beam power. Studies are ongoing for further higher beam power of 1.5 MW. The injection and extraction energy of RCS is 0.4 and 3 GeV, respectively. Lifetime of the stripper foil is the highest concern beyond 1 MW beam power. We have also already started detail studies of H⁻ stripping to protons by using lasers. However, in order to avoid high magnetic field required in the process of laser-assisted H⁻ stripping to protons, especially for lower H⁻ energies, we are studying the possibilities of using only laser system for 400 MeV H⁻ beam in the RCS. The method is a three step process, similar to that of SNS but lasers are used instead of high field magnets in the 1st (H⁻ to H⁰) and 3rd step (H0* to p). A Nd:YAG laser can be properly used for both 1st and 3rd steps, where commercially available powerful Excimer laser will be used an H⁰ excitation in the 2nd step. Although detail R&D studies are necessary to reach to the ultimate goal, we plan to carry out an experiment in 2017. A detail of the present method, experimental schedule and the expected outcome will be presented.

Slides TUPM7X01 [3.316 MB]

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TUPM3Y01

Operational Experience and Future Plans at ISIS

operation, acceleration, proton, simulation

333

D.J. Adams
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
I.S.K. Gardner, B. Jones, A.H. Kershaw, A.P. Letchford, R.J. Mathieson, A. Pertica, B.G. Pine, A. Seville, H. V. Smith, C.M. Warsop, R.E. Williamson, M. Wright
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The ISIS spallation neutron and muon source has been in operation since 1984. The accelerator complex consists of an H⁻ ion source, 665 keV RFQ, 70 MeV linac, 800 MeV proton synchrotron and associated beam transfer lines. The facility currently delivers ~2.8·10¹³ protons per pulse (ppp) at 50 Hz, which is shared between two target stations. High intensity performance and operation are dominated by the need to minimise and control beam loss, which is key to sustainable machine operation, allowing essential hands on maintenance. The facility has had several upgrades including an RFQ, ring Second Harmonic RF system, key developments of diagnostics and instrumentation required for improving beam control and a Second Target station. Upgrades being installed, or expected in the near future, include: a ring damping system, a new injector MEBT with fast injection chopper and an upgraded 50 Hz target. Operational experience of ISIS and the impacts of its past and future upgrades are discussed. Ideas for major upgrades to ISIS are briefly reviewed, as are the underlying R&D projects.

Slides TUPM3Y01 [2.902 MB]

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WEAM6X01

Studies of High Intensity Proton FFAGs at RAL

proton, linac, emittance, 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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THAM6X01

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

resonance, emittance, 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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THPM9X01

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

emittance, 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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