HB2018 - List of Keywords (emittance)

Paper	Title	Other Keywords	Page
MOA1PL01	Challenges in Understanding Space Charge Dynamics	space-charge, resonance, simulation, synchrotron	1
	H. Bartosik CERN, Geneva, Switzerland
	Space charge effects in high intensity and high brightness synchrotrons can lead to undesired beam emittance growth, beam halo formation and particle loss. A series of dedicated machine experiments has been performed over the past decade in order to study these effects in the particular regime of long-term beam storage (10⁵-10⁶ turns) as required for certain applications. This paper gives an overview of the present understanding of the underlying beam dynamics mechanisms. In particular it focuses on the space charge induced periodic resonance crossing, which has been identified as the main mechanism causing beam degradation in this regime. The challenges in further progressing with the understanding, the modelling and the mitigation of these space charge effects and the resulting beam degradation are discussed. Furthermore, an outlook for possible future directions of studies is presented.
	Slides MOA1PL01 [22.877 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOA1PL01
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MOA1PL02	Beam Dynamics Challenges for the LHC and Injector Upgrades	injection, brightness, impedance, space-charge	8
	G. Rumolo CERN, Geneva, Switzerland
	The High Luminosity upgrade of the Large Hadron Collider (HL-LHC) will rely on significantly higher bunch current and brightness to meet the future yearly integrated luminosity target. The implications are twofold. On one side, all the accelerators of the LHC injection chain will have to be upgraded to produce the desired beam parameters. For this purpose, the LHC Injectors Upgrade (LIU) program has been established to implement all the needed modifications for meeting the required beam specifications. These upgrades will lead to the lifting of the main intensity and brightness limitations in the injectors, linked to beam instabilities driven by impedance or electron cloud (e-cloud), and space charge. On the other side, the LHC will have to be able to swallow the new beam parameters. This will mainly require control of impedance driven instabilities and beam-beam effects, and e-cloud mitigation. In this paper, we will focus on proton beams by describing the identified performance limitations of the LHC and its injectors, as well as the actions envisioned to overcome them.
	Slides MOA1PL02 [13.138 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOA1PL02
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MOA1PL03	Linac4 Commissioning Status and Challenges to Nominal Operation	linac, MMI, operation, injection	14
	G. Bellodi CERN, Geneva, Switzerland
	Linac4 will be connected to the Proton Synchrotron Booster (PSB) during the next long LHC shutdown in 2019 and it will operationally replace Linac2 as provider of protons to the CERN complex as of 2021. Commissioning to the final beam energy of 160 MeV was achieved by the end of 2016. Linac4 is presently under-going a reliability and beam quality test run to meet the beam specifications and relative tolerances requested by the PSB. In this paper we will detail the main challenges left before achieving nominal operation and we will re-port on the commissioning steps still needed for final validation of machine readiness before start of operation.
	Slides MOA1PL03 [20.659 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOA1PL03
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MOP1WA01	J-PARC RCS: Effects of Emittance Exchange on Injection Painting	operation, injection, space-charge, betatron	20
	H. Hotchi JAEA/J-PARC, Tokai-mura, Japan
	The J-PARC RCS is a high-power rapid cycling synchrotron aiming for a 1-MW output beam power. This talk reports the recent progress of the J-PARC RCS beam commissioning and operation especially focusing on our efforts for beam dynamics issues that we faced during the process of the beam power ramp-up.
	Slides MOP1WA01 [4.081 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOP1WA01
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MOP2WA01	Beam Physics Limitations for Damping of Instabilities in Circular Accelerators	damping, betatron, pick-up, kicker	26
	V.A. Lebedev Fermilab, Batavia, Illinois, USA
	Funding: Work supported by D.O.E. Contract No. DE-AC02-07CH11359 The paper considers a beam interaction with a feedback system and major limitations on the beam damping rate. In particular, it discusses: limitations on the system gain and damping rate, feedback system noise and its effect on the beam emittance growth, x-y coupling effect on damping, suppression of high order modes and damping of slip-stacked beams.
	Slides MOP2WA01 [0.408 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOP2WA01
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MOP1WB03	Experimental Study of Beam Dynamics in the PIP-II MEBT Prototype	rfq, cavity, optics, simulation	54
	A.V. Shemyakin, J.-P. Carneiro, B.M. Hanna, V.A. Lebedev, L.R. Prost, A. Saini, V.E. Scarpine Fermilab, Batavia, Illinois, USA C.J. Richard NSCL, East Lansing, Michigan, USA V.L. Sista BARC, Mumbai, India
	Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics The Proton Improvement Plan, Stage Two (PIP-II) is a program of upgrades proposed for the Fermilab injection complex, which central part is an 800-MeV, 2-mA CW SRF linac. A prototype of the PIP-II linac front end called PIP-II Injector Test (PIP2IT) is being built at Fermilab. As of now, a 15-mA DC, 30-keV H⁻ ion source, a 2 m-long Low Energy Beam Transport (LEBT), a 2.1-MeV CW RFQ, followed by a 10-m Medium Energy Beam Transport (MEBT) have been assembled and commissioned. The MEBT bunch-by-bunch chopping system and the requirement of a low uncontrolled beam loss put stringent limitations on the beam envelope and its variation. Measurements of transverse and longitudinal beam dynamics in the MEBT were performed in the range of 1-10 mA of the RFQ beam current. Almost all measurements are made with 10 μs beam pulses in order to avoid damage to the beam line. This report presents measurements of the transverse optics with differential trajectories, reconstruction of the beam envelope with scrapers and an Allison emittance scanner, as well as bunch length measurements with a Fast Faraday Cup.
	Slides MOP1WB03 [3.750 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOP1WB03
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MOP2WB02	Simulation and Measurement Campaigns for Characterization and Performance Improvement of the CERN Heavy Ion Linac3	linac, simulation, extraction, rfq	64
	G. Bellodi, S. Benedetti, D. Küchler, F.J.C. Wenander CERN, Geneva, Switzerland V. Toivanen GANIL, Caen, France
	In the framework of the LHC Injector Upgrade programme (LIU), several activities have been carried out to improve the GTS-LHC ion source and Linac3 performance (Linac3 providing the charged heavy ion beams for CERN exper-iments). A restudy of the beam dynamics and transport through the linac was initiated, through a campaign of systematic machine measurements and parallel beam simulations, generalising techniques developed for beam characterization during Linac4 commissioning. The work here presented will review the most relevant findings and lessons learnt in the process.
	Slides MOP2WB02 [17.512 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOP2WB02
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MOP2WB03	Emittance Growth and Beam Losses in LANSCE Linear Accelerator	beam-losses, proton, DTL, linac	70
	Y.K. Batygin, R.W. Garnett, L. Rybarcyk LANL, Los Alamos, New Mexico, USA
	Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396. The LANSCE Accelerator facility currently utilizes four 800 MeV H⁻ beams and one 100 MeV proton beam. Multi-beam operation requires careful control of accelerator tune to minimize beam losses. The most powerful 80 kW H⁻ beam is accumulated in the Proton Storage Ring and is extracted to the Lujan Neutron Scattering Center facility for production of moderated neutrons with meV-keV energy. Another H⁻ beam is delivered to the Weapon Neutron Research facility to create un-moderated neutrons in the keV - MeV energy range. The third H⁻ beam is shared between the Proton Radiography Facility and the Ultra-Cold Neutron facility. The 23 kW proton beam is used for isotope production in the fields of medicine, nuclear physics, national security, environmental science and industry. Minimization of beam losses in the linac is achieved due to careful tuning of the beam in each section of the accelerator facility, imposing restrictions on amplitudes and phases of RF sections, control of H⁻ beam stripping, and optimization of ion sources operation. This paper summarizes experimental results in accelerator operations and categorizes various sources of emittance growth and beam losses.
	Slides MOP2WB03 [4.570 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-MOP2WB03
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TUA1WC01	Installation and Commissioning of the Upgraded SARAF 4-rods RFQ	rfq, operation, proton, linac	75
	L. Weissman, D. Berkovits, B. Kaizer, J. Luner, D. Nusbaum, A. Perry, J. Rodnizki, A. Shor, I. Silverman Soreq NRC, Yavne, Israel A. Bechtold NTG Neue Technologien GmbH & Co KG, Gelnhausen, Germany
	Acceleration of a 1mA Continuous Wave (CW) deuteron (A/Q=2) beam at SARAF has been accomplished for the first time. A 5.3 mA pulsed deuteron beam has been accelerated as well. These achievements cap a series of major modifications to the Radio Frequency Quadrupole (RFQ) 4-rods structure which included the incorporation of a new end flange, introduction of an additional RF power coupler and, most recently, installation of a new set of rod electrodes. The new rod modulation has been designed to enable deuteron beam acceleration at a lower inter-electrode voltage, to a slightly reduced final energy of 1.27 MeV/u and with stringent constraints on the extant of beam tails in the longitudinal phase space. This report will focus primarily on the installation and testing of the new rods. The successful conditioning campaign to 200 kW, ~10% above than the working point for deuteron operation, will be described. Beam commissioning with proton and deuteron beams will also be detailed. Results of beam measurements will be presented, including the characterization of the output beam in the transverse and longitudinal phase space. Finally, future possible improvements are discussed.
	Slides TUA1WC01 [12.606 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-TUA1WC01
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TUA2WC03	Studies on Superconducting Deuteron Driver Linac for BISOL	cavity, linac, ISOL, SRF	88
	F. Zhu, M. Chen, A.Q. Cheng, J.K. Hao, H.P. Li, S.W. Quan, F. Wang PKU, Beijing, People's Republic of China
	Funding: Work supported by National Basic Research Project (No. 2014CB845504) Beijing isotope separation on line type rare ion beam facility (BISOL) for both basic science and applications is a project proposed by China Institute of Atomic Energy and Peking University. Deuteron driver accelerator of BISOL would adopt superconducting half wave resonators (HWRs) with low beta and high current. The HWR cavity performance and the beam dynamic simulation of the superconducting deuteron driver accelerator will be presented in this paper.
	Slides TUA2WC03 [10.028 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-TUA2WC03
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TUP1WA03	Beam Instabilities After Injection to the LHC	injection, simulation, controls, operation	163
	H. Timko, T. Argyropoulos, I. Karpov, E.N. Shaposhnikova CERN, Geneva, Switzerland
	Long-lasting phase oscillations have been observed at injection into the LHC since its first start-up with beam. These oscillations, however, were not leading to noticeable losses or blow-up in operation, and were therefore not studied in detail. In 2017, dedicated measurements with high-intensity bunches revealed that oscillations can lead to losses even slightly below the baseline intensity for the high-luminosity upgrade of the LHC. For the first time, high-resolution bunch profile acquisitions were triggered directly at injection and the formation of large-amplitude non-rigid dipole oscillations was observed on a turn-by-turn basis. First simulations can reproduce this instability via bunch filamentation that takes place after injection, depending on the mismatch between the bunch and bucket size in momentum at injection.
	Slides TUP1WA03 [2.166 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-TUP1WA03
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TUP2WA02	Momentum Slip-Stacking Simulations for CERN SPS Ion Beams with Collective Effects	simulation, flattop, ECR, cavity	174
	D. Quartullo, T. Argyropoulos, A. Lasheen CERN, Geneva, Switzerland
	The LHC Injectors Upgrade (LIU) Project at CERN aims at doubling the total intensity of the Pb-ion beam for the High-Luminosity LHC (HL-LHC) project. This goal can be achieved by using momentum slip-stacking (MSS) in the SPS, the LHC injector. This RF gymnastics, originally proposed to increase bunch intensity, will be used on the intermediate energy plateau to interleave two batches, reducing the bunch spacing from 100 to 50 ns. The MSS feasibility can be tested only in 2021, after the beam controls upgrade of the SPS 200 MHz RF system, so beam dynamics simulations are used to design this complicated beam manipulation. Simulations of the MSS were performed using the CERN BLonD code with a full SPS impedance model. Attention has been paid to the choice of the RF and machine parameters (beam energy, time duration, RF frequency and voltage programmes) to reduce losses and the final bunch length which is crucial for the injection into the LHC 400 MHz buckets. The initial beam parameters used in simulations were obtained from beam measurements in the first part of the SPS cycle taking into account bunch-by-bunch losses on flat bottom and development of bunch instabilities.
	Slides TUP2WA02 [8.272 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-TUP2WA02
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WEA2WB02	Recent Studies of Beam Physics for Ion Linacs	DTL, injection, cavity, linac	200
	L. Groening, S. Appel, X. Du, P. Gerhard, M.T. Maier, A. Rubin, P. Scharrer, H. Vormann, C. Xiao GSI, Darmstadt, Germany M. Chung UNIST, Ulsan, Republic of Korea P. Scharrer HIM, Mainz, Germany P. Scharrer Mainz University, Mainz, Germany
	The UNIversal Linear ACcelerator (UNILAC) at GSI aims at provision of high brilliant ion beams, as it main purpose will be to serve as injector for the upcoming FAIR accelerator complex. The UNILAC injects into the subsequent synchrotron SIS18 applying horizontal multi-turn injection (MTI). Optimization of this process triggered intense theoretical and experimental studies of dynamics of transversely coupled beams. These activities comprise round-to-flat beam transformation, full 4d transverse beam diagnostics, optimization of the MTI parameters through generic algorithms, and extension of Busch's theorem to accelerated particle beams. Finally, recent advance in modeling time-transition-factors and its impact on improved linac performance will be presented as well as progress in the optimization of ion charge state stripping.
	Slides WEA2WB02 [4.772 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEA2WB02
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WEP1WB02	Beam Dynamics Simulation and Measurements for the IFMIF/EVEDA Project	rfq, simulation, space-charge, proton	210
	M. Comunian, L. Antoniazzi, A. Baldo, C. Baltador, L. Bellan, D. Bortolato, M. Cavenago, E. Fagotti, M.G. Giacchini, F. Grespan, M. Montis, A. Palmieri, A. Pisent, F. Scantamburlo INFN/LNL, Legnaro (PD), Italy L. Bellan Univ. degli Studi di Padova, Padova, Italy N. Chauvin IRFU, CEA, University Paris-Saclay, Gif-sur-Yvette, France H. Dzitko F4E, Germany
	In the framework of IFMIF/EVEDA project the source and RFQ are ready to be tested with beam. In this article the beam dynamics simulation and the measurement performed in preparation of the first beam injection are presented. The installed line is composed by the proton and deuteron Source with the LEBT composed of two solenoids that inject in the 10 meters long RFQ, the MEBT, diagnostic plate and the beam dump. The line is prepared to be tested with protons of 8 mA in pulsed mode (up to 0.1%).
	Slides WEP1WB02 [10.303 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP1WB02
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WEP1WB03	First Heavy Ion Beam Acceleration with a Superconducting Multi Gap CH-cavity	cavity, linac, heavy-ion, acceleration	215
	W.A. Barth, M. Heilmann, A. Rubin, A. Schnase, S. Yaramyshev GSI, Darmstadt, Germany K. Aulenbacher, W.A. Barth, F.D. Dziuba, V. Gettmann, T. Kürzeder, M. Miski-Oglu HIM, Mainz, Germany K. Aulenbacher IKP, Mainz, Germany M. Basten, M. Busch, H. Podlech, M. Schwarz IAP, Frankfurt am Main, Germany
	A newly developed superconducting 15-gap RF-cavity has been successfully tested at GSI Helmholtzzentrum für Schwerionenforschung. After a short commissioning and ramp up time of some days, a Crossbar H-cavity accelerated first time heavy ion beams with full transmission up to the design beam energy of 1.85 MeV/u. The design acceleration gain of 3.5 MV inside a length of less than 70 cm has been verified with heavy ion beam of up to 1.5 particle mueA. The measured beam parameters showed excellent beam quality, while a dedicated beam dynamics layout provides beam energy variation between 1.2 and 2.2 MeV/u. The beam commissioning is a milestone of the R&D work of Helmholtz Institute Mainz and GSI in collaboration with Goethe University Frankfurt towards a superconducting heavy ion continuous wave linear accelerator cw-Linac with variable beam energy. Further linac beam dynamics layout issues will be presented as well.
	Slides WEP1WB03 [20.157 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP1WB03
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WEA1WA02	Approaching the High-Intensity Frontier Using the Multi-Turn Extraction at the CERN Proton Synchrotron	extraction, proton, operation, synchrotron	231
	A. Huschauer, H. Bartosik, S. Cettour-Cave, M. R. Coly, D.G. Cotte, H. Damerau, G.P. Di Giovanni, S.S. Gilardoni, M. Giovannozzi, V. Kain, E. Koukovini-Platia, B. Mikulec, G. Sterbini, F. Tecker CERN, Geneva, Switzerland
	Complementary to the physics research at the LHC, several fixed target facilities receive beams from the LHC injector complex. In the scope of the fixed target physics program at the Super Proton Synchrotron, high-intensity proton beams from the Proton Synchrotron are extracted using the Multi-Turn Extraction scheme, which is based on particle trapping in stable islands of the horizontal phase space. Considering the number of protons requested by future experimental fixed target facilities, such as the Search for Hidden Particles experiment, the currently operationally delivered beam intensities are insufficient. Therefore, experimental studies have been conducted to optimize the Multi-Turn Extraction technique and to exploit the possible intensity reach. The results of these studies along with the operational performance of high-intensity beams during the 2017 run are presented in this paper. Furthermore, the impact of the hardware changes pursued in the framework of the LHC Injectors Upgrade project on the high-intensity beam properties is briefly mentioned.
	Slides WEA1WA02 [25.566 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEA1WA02
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WEA2WA01	High Intensity Effects of Fixed Target Beams in the CERN Injector Complex	impedance, simulation, space-charge, proton	237
	E. Koukovini-Platia, H. Bartosik, M. Migliorati, G. Rumolo CERN, Geneva, Switzerland M. Migliorati INFN-Roma1, Rome, Italy M. Migliorati Sapienza University of Rome, Rome, Italy
	The current fixed target (FT) experiments at CERN are a complementary approach to the Large Hadron Collider (LHC) and play a crucial role in the investigation of fundamental questions in particle physics. Within the scope of the LHC Injectors Upgrade (LIU), aiming to improve the LHC beam production, the injector complex will be significantly upgraded during the second Long Shutdown (LS2). All non-LHC beams are expected to benefit from these upgrades. In this paper, we focus on the studies of the transverse instability in the Proton Synchrotron (PS), currently limiting the intensity of Time-Of-Flight (ToF) type beams, as well as the prediction of the impact of envisaged hardware modifications. A first discussion on the effect of space charge on the observed instability is also being presented.
	Slides WEA2WA01 [2.483 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEA2WA01
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WEP1WA03	IBS Near Transition Crossing in NICA Collider	collider, optics, lattice, focusing	252
	S.A. Kostromin, A.O. Sidorin JINR, Dubna, Moscow Region, Russia I.V. Gorelyshev JINR/VBLHEP, Dubna, Moscow region, Russia V.A. Lebedev Fermilab, Batavia, Illinois, USA A.O. Sidorin Saint Petersburg State University, Saint Petersburg, Russia
	Intrabeam scattering (IBS) of charged particles in a particle beam results in an exchange of energy between different degrees of freedom. That results in an increase of average energy of particles in the beam frame and an increase of the 3D-emittance. The paper considers calculations of beam emittance growth rates for different options of NICA collider and IBS effects in close vicinity of the transition.
	Slides WEP1WA03 [1.774 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP1WA03
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WEP2PO006	Overview of the CERN PSB-to-PS Transfer Line Optics Matching Studies in View of the LHC Injectors Upgrade Project	optics, operation, injection, quadrupole	272
	V. Forte, S.C.P. Albright, W. Bartmann, G.P. Di Giovanni, M.A. Fraser, C. Heßler, A. Huschauer, A. Oeftiger CERN, Geneva, Switzerland
	At injection into the CERN Proton Synchrotron (PS) a significant horizontal emittance blow-up of the present high brightness beams for the LHC is observed. A partial contribution to this effect is suspected to be an important mismatch between the dispersion function in the transfer line from the PS Booster (PSB) and the ring itself. This mismatch will be unacceptable in view of the beam parameters requested by the LHC Injectors Upgrade (LIU) project with high longitudinal emittance and momentum spread. To deliver the requested beam parameters the PSB-to-PS transfer line will be upgraded and the optics in the line changed to improve the matching from all the four PSB rings. A re-matching campaign from the PSB ring 3 has been carried out to evaluate the impact of the present optics mismatch as a source of emittance growth both in simulations and measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO006
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WEP2PO007	Multi-Particle Simulations of the Future CERN PSB Injection Process with Updated Linac4 Beam Performance	injection, linac, optics, simulation	278
	V. Forte, C. Bracco, G.P. Di Giovanni, M.A. Fraser, A.M. Lombardi, B. Mikulec CERN, Geneva, Switzerland
	In the framework of the LHC Injectors Upgrade (LIU) project, the injection process in the CERN Proton Synchrotron Booster (PSB) will be renovated after the connection with the Linac4. A new H⁻ charge exchange injection system using a stripping foil is foreseen to increase the brightness of the stored beams and to provide high flexibility in terms of emittance tailoring at 160 MeV. Realistic multi-particle simulations of the future injection processes for high brightness beams (i.e. for the LHC) and high intensity beams (i.e. for the ISOLDE experiment) are presented in this paper. The simulations are based on the present performance of Linac4 and include scattering induced by the foil, space charge effects and compensation of the lattice perturbation introduced by the bumpers of the injection chicane.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO007
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WEP2PO011	Studies of Transverse Instabilities in the CERN SPS	simulation, octupole, optics, injection	291
	M.S. Beck, H. Bartosik, M. Carlà, K.S.B. Li, G. Rumolo, M. Schenk CERN, Geneva, Switzerland U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	In the framework of the LHC Injectors Upgrade (LIU), beams with about twice the intensity compared to the present values will have to be accelerated by the CERN Super Proton Synchrotron (SPS) and extracted towards the Large Hadron Collider (LHC). Machine studies with intensity higher than the nominal LHC beam have shown that coherent instabilities in both transverse planes may develop at injection energy, potentially becoming a limitation for the future high intensity operation. In particular, a transverse mode coupling instability is encountered in the vertical plane, the threshold of which can be sufficiently increased by changing the machine optics. In addition, a headtail instability of individual bunches is observed in the horizontal plane in multi-bunch operation, which requires stabilization by high chromaticity. The PyHEADTAIL code has been used to check if the present SPS impedance model reproduces the experimental observations. The instability growth rates have been studied for different machine optics configurations and different chromaticity settings. Other stabilizing mechanisms like tune spread from octupoles or the transverse damper have also been investigated.
	Poster WEP2PO011 [4.940 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO011
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WEP2PO027	Simulation of the Axial Injection Beam Line of the Reconstructed U200 Cyclotron of FLNR JINR	cyclotron, solenoid, ECR, injection	319
	N.Yu. Kazarinov, J. Franko, G.G. Gulbekyan, I.A. Ivanenko, I.V. Kalagin JINR, Dubna, Moscow Region, Russia
	Flerov Laboratory of Nuclear Reaction of Joint Institute for Nuclear Research begin the works under reconstruction of the cyclotron U200. The reconstructed cyclotron is intended for acceleration of heavy ions with mass-to-charge ratio A/Z within interval from 5 to 8 up to the fixed energies 3.5 and 5.3 MeV per unit mass. The intensity of the accelerated ions will be about 3 pmcA for lighter ions (A< 40) and about 0.3 pmcA for heavier ions (A<132). The cyclotron will be used in the microchip testing, production of the track pore membranes and for applied physics. The injection into cyclotron will be realized from the external superconducting ECR ion source. The simulation of the axial injection system of the cyclotron is presented in this report.
	Poster WEP2PO027 [0.679 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-WEP2PO027
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THA1WD04	High-Brightness Challenges for the Operation of the CERN Injector Complex	injection, linac, brightness, proton	352
	K. Hanke, S.C.P. Albright, R. Alemany-Fernández, H. Bartosik, E. Chapochnikova, H. Damerau, G.P. Di Giovanni, B. Goddard, A. Huschauer, V. Kain, A. Lasheen, M. Meddahi, B. Mikulec, G. Rumolo, R. Scrivens, F. Tecker CERN, Geneva, Switzerland
	CERN's LHC injectors are delivering high-brightness proton and ion beams for the Large Hadron Collider LHC. We review the present operation modes and beam performance, and highlight the limitations. We will then give an overview of the upgrade program that has been put in place to meet the demands of the LHC during the High-Luminosity LHC era.
	Slides THA1WD04 [4.746 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-THA1WD04
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THA2WD01	Operation Challenges and Performance of the LHC During Run II	luminosity, MMI, operation, brightness	357
	R. Steerenberg, J. Wenninger CERN, Geneva, Switzerland
	The CERN Large Hadron Collider Run II saw an important increase in beam performance through both, improvements in the LHC and an increased beam brightness from the injectors, leading to a peak luminosity that exceeds the LHC design luminosity by more than a factor two. This contribution will give an overview of run 2, the main challenges encountered and it will address the measures applied to deal with and make use of the increased beam brightness. Finally potential areas where further performance improvement can be a realized will be identified.
	Slides THA2WD01 [6.709 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-HB2018-THA2WD01
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THP1WB01	Commissioning Status of Linear IFMIF Prototype Accelerator (LIPAc)	rfq, MMI, acceleration, cavity	366
	A. Kasugai, T. Akagi, T. Ebisawa, Y. Hirata, R. Ichimiya, K. Kondo, S. Maebara, K. Sakamoto, T. Shinya, M. Sugimoto QST, Aomori, Japan P. Abbon, N. Bazin, B. Bolzon, N. Chauvin, S. Chel, R. Gobin, J. Marroncle, B. Renard CEA/DSM/IRFU, France L. Antoniazzi, L. Bellan, D. Bortolato, M. Comunian, E. Fagotti, F. Grespan, M. Montis, A. Palmieri, A. Pisent INFN/LNL, Legnaro (PD), Italy P.-Y. Beauvais, H. Dzitko, D. Gex, A. Jokinen, G. Phillips F4E, Germany P. Cara, R. Heidinger, I. Moya Fusion for Energy, Garching, Germany D. Jiménez-Rey, I. Kirpitchev, J. Mollá, P. Méndez, I. Podadera, D. Regidor, M. Weber, C. de la Morena CIEMAT, Madrid, Spain J. Knaster, A. Marqueta, G. Pruneri, F. Scantamburlo IFMIF/EVEDA, Rokkasho, Japan
	The IFMIF project aiming at material tests for a future fusion DEMO reactor is under the EVEDA phase in the BA Agreement of fusion program between Japan and EU. As the accelerator activity, the installation and commissioning of the Linear IFMIF Prototype Accelerator (LIPAc) is at the second stage of demonstration of the feasibility of the low energy section of an IFMIF deuteron accelerator up to 9 MeV with a beam current of 125 mA, CW. The installation of injector, RFQ, MEBT, D-Plate and LPBD for LIPAc with 8 coaxial high-power transmission lines and RF power system was just done in 2017 at Rokkasho, Japan. After that, the RF conditioning of RFQ for beam commissioning is underway. The beam commissioning of RFQ with H⁺/D⁺ and the acceleration demonstration up to 5 MeV-125 mA-0.1% duty cycle with D⁺ will be done.
	Slides THP1WB01 [13.177 MB]
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THP2WB01	Revisiting the Longitudinal 90 Degree Limit for Superconducting Linear Accelerators	space-charge, lattice, resonance, focusing	369
	I. Hofmann GSI, Darmstadt, Germany I. Hofmann TEMF, TU Darmstadt, Darmstadt, Germany
	In the design of high-intensity linear accelerators one of the generally adopted criteria is not to exceed a zero-current phase advance per focusing period of 90 degrees in order to avoid the space charge driven envelope instability, or a coinciding fourth order space charge resonance. Recently it was claimed that in certain structures, predominantly applicable to super-conducting linac lattices - such a constraint is not always necessary in the longitudinal plane (I. Hofmann and O. Boine-Frankenheim, Phys. Rev. Lett. 118, 2017). This applies primarily to such focusing structures, where the transverse focusing period only induces a weak space charge dependent modulation in the longitudinal plane, and a different periodicity is applicable to the longitudinal plane. Hence the longitudinal 90 degree stopband is practically absent, and phase advances significantly above 90 degrees should be possible in such structures, with a corresponding additional design freedom. As a consequence, we suggest that the 90 degree rule should no longer be taken as standard criterion in the longitudinal plane of linac design.
	Slides THP2WB01 [5.179 MB]
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THP2WB02	High-Intensity Beam Dynamics Simulation of the IFMIF-like Accelerators	simulation, space-charge, beam-transport, rfq	373
	S.H. Moon, M. Chung UNIST, Ulsan, Republic of Korea
	Funding: This research was supported by the National Research Foundation of Korea (Grant No. NRF-2017M1A7A1A02016413). The IFMIF (International Fusion Material Irradiation Facility) project is being considered to build fusion material test facility. The IFMIF will use two accelerators to generate high energy neutrons. However, the IFMIF accelerators have been designed to have much higher beam power and beam current than the existing accelerators, so space charge effect is very strong. This raises big concerns about beam loss and beam transport stability, thus detailed high-intensity beam dynamics study of the IFMIF-like accelerators is indispensable. This research aims to perform source to target simulation of the IFMIF-like accelerator. The simulation has been carried out by two different kinds of simulation codes because the IFMIF accelerator has distinctive features. One is TRACEWIN simulation code which was used in IFMIF initial design. The other is WARP 3D PIC code which can precisely calculate space charge effects. This presentation will focus on beam simulations for LEBT, RFQ, and MEBT of the IFMIF accelerator
	Slides THP2WB02 [10.583 MB]
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THA1WE02	Requirements and Results for Quadrupole Mode Measurements	space-charge, synchrotron, quadrupole, pick-up	393
	A. Oeftiger CERN, Geneva, Switzerland
	Funding: Research supported by the HL-LHC project. Direct space charge may be quantified, and hence the beam brightness observed, by measuring the quadrupolar beam modes in the CERN Proton Synchrotron (PS). The spectrum of the transverse beam size oscillations (i.e. the quadrupolar beam moment) contains valuable information: the betatron envelope modes and the coherent dispersive mode indicate optics mismatch, while their frequency shifts due to space charge allow a direct measurement thereof. To measure the quadrupolar beam moment we use the Base-Band Q-meter system of the PS which is based on a four electrode stripline pick-up. Past experiments with quadrupolar pick-ups often investigated coasting beams, where the coherent betatron and dispersion modes correspond to single peaks in the tune spectrum. In contrast, long bunched beams feature bands of betatron modes: the mode frequencies shift depending on the transverse space charge strength which varies with the local line charge density. By using the new transverse feedback in the PS as a quadrupolar RF exciter, we measured the quadrupolar beam transfer function. The beam response reveals the distinct band structure of the envelope modes as well as the coherent dispersive mode.
	Slides THA1WE02 [7.315 MB]
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THA1WE03	BPM Technologies for Quadrupolar Moment Measurements	pick-up, factory, multipole, electron	399
	A. Sounas, M. Gąsior, T. Lefèvre CERN, Geneva, Switzerland
	Quadrupolar moment measurements based on electromagnetic pick-ups (PU), like BPMs, have attracted particular interest as non-intercepting diagnostics to determine the transverse beam size. Here, the second-order moment, which contains information about the beam size, is extracted from the BPM electrode signals. Despite the simplicity of the concept, quadrupololar measurements have always been challenging in practice. This is related to the fact that the quadrupolar moment constitutes only a very small part of the total PU signal, which is dominated by the contributions of beam intensity and position. In this study we discuss the limitations of absolute quadrupolar measurements if applying traditional BPM technologies, and we propose a new approach to efficiently overcome them via movable PUs. Moreover, we highlight the potential use of BPMs as an emittance measurement system during the energy ramp at synchrotrons by performing differential quadrupolar measurements, which show a remarkably higher accuracy than absolute measurements. Dedicated studies using different types of BPMs in the Large Hadron Collider (LHC) at CERN demonstrated promising results.
	Slides THA1WE03 [5.299 MB]
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THP2WC02	LLRF Studies for HL-LHC Crab Cavities	cavity, feedback, luminosity, betatron	440
	P. Baudrenghien CERN, Geneva, Switzerland T. Mastoridis CalPoly, San Luis Obispo, California, USA
	The HL-LHC upgrade includes sixteen Crab Cavities (CC) to be installed on both sides of the high luminosity experiments, ATLAS and CMS. Two issues have been highlighted for the Low Level RF: transverse emittance growth (and associated luminosity drop) caused by CC RF noise, and large collimator losses following a CC trip. A prototype cryomodule with two CCs has been installed in the SPS, and tests have started in May 2018 with beam. This paper briefly reports on preliminary results from the SPS tests. It then presents emittance growth calculations from cavity field phase and amplitude noise, deduces the maximum RF noise compatible with the specifications and presents a possible cure consisting of a feedback on CC phase and amplitude. To reduce the losses following a CC trip we propose to implement transverse tail cleaning via the injection of CC noise with an optimized spectrum, which selectively excites the particles of large transverse oscillation amplitudes.
	Slides THP2WC02 [1.943 MB]
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Paper

Title

Other Keywords

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MOA1PL01

Challenges in Understanding Space Charge Dynamics

space-charge, resonance, simulation, synchrotron

1

H. Bartosik
CERN, Geneva, Switzerland

Space charge effects in high intensity and high brightness synchrotrons can lead to undesired beam emittance growth, beam halo formation and particle loss. A series of dedicated machine experiments has been performed over the past decade in order to study these effects in the particular regime of long-term beam storage (10⁵-10⁶ turns) as required for certain applications. This paper gives an overview of the present understanding of the underlying beam dynamics mechanisms. In particular it focuses on the space charge induced periodic resonance crossing, which has been identified as the main mechanism causing beam degradation in this regime. The challenges in further progressing with the understanding, the modelling and the mitigation of these space charge effects and the resulting beam degradation are discussed. Furthermore, an outlook for possible future directions of studies is presented.

Slides MOA1PL01 [22.877 MB]

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MOA1PL02

Beam Dynamics Challenges for the LHC and Injector Upgrades

injection, brightness, impedance, space-charge

8

G. Rumolo
CERN, Geneva, Switzerland

The High Luminosity upgrade of the Large Hadron Collider (HL-LHC) will rely on significantly higher bunch current and brightness to meet the future yearly integrated luminosity target. The implications are twofold. On one side, all the accelerators of the LHC injection chain will have to be upgraded to produce the desired beam parameters. For this purpose, the LHC Injectors Upgrade (LIU) program has been established to implement all the needed modifications for meeting the required beam specifications. These upgrades will lead to the lifting of the main intensity and brightness limitations in the injectors, linked to beam instabilities driven by impedance or electron cloud (e-cloud), and space charge. On the other side, the LHC will have to be able to swallow the new beam parameters. This will mainly require control of impedance driven instabilities and beam-beam effects, and e-cloud mitigation. In this paper, we will focus on proton beams by describing the identified performance limitations of the LHC and its injectors, as well as the actions envisioned to overcome them.

Slides MOA1PL02 [13.138 MB]

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MOA1PL03

Linac4 Commissioning Status and Challenges to Nominal Operation

linac, MMI, operation, injection

14

G. Bellodi
CERN, Geneva, Switzerland

Linac4 will be connected to the Proton Synchrotron Booster (PSB) during the next long LHC shutdown in 2019 and it will operationally replace Linac2 as provider of protons to the CERN complex as of 2021. Commissioning to the final beam energy of 160 MeV was achieved by the end of 2016. Linac4 is presently under-going a reliability and beam quality test run to meet the beam specifications and relative tolerances requested by the PSB. In this paper we will detail the main challenges left before achieving nominal operation and we will re-port on the commissioning steps still needed for final validation of machine readiness before start of operation.

Slides MOA1PL03 [20.659 MB]

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MOP1WA01

J-PARC RCS: Effects of Emittance Exchange on Injection Painting

operation, injection, space-charge, betatron

20

H. Hotchi
JAEA/J-PARC, Tokai-mura, Japan

The J-PARC RCS is a high-power rapid cycling synchrotron aiming for a 1-MW output beam power. This talk reports the recent progress of the J-PARC RCS beam commissioning and operation especially focusing on our efforts for beam dynamics issues that we faced during the process of the beam power ramp-up.

Slides MOP1WA01 [4.081 MB]

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MOP2WA01

Beam Physics Limitations for Damping of Instabilities in Circular Accelerators

damping, betatron, pick-up, kicker

26

V.A. Lebedev
Fermilab, Batavia, Illinois, USA

Funding: Work supported by D.O.E. Contract No. DE-AC02-07CH11359
The paper considers a beam interaction with a feedback system and major limitations on the beam damping rate. In particular, it discusses: limitations on the system gain and damping rate, feedback system noise and its effect on the beam emittance growth, x-y coupling effect on damping, suppression of high order modes and damping of slip-stacked beams.

Slides MOP2WA01 [0.408 MB]

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MOP1WB03

Experimental Study of Beam Dynamics in the PIP-II MEBT Prototype

rfq, cavity, optics, simulation

54

A.V. Shemyakin, J.-P. Carneiro, B.M. Hanna, V.A. Lebedev, L.R. Prost, A. Saini, V.E. Scarpine
Fermilab, Batavia, Illinois, USA
C.J. Richard
NSCL, East Lansing, Michigan, USA
V.L. Sista
BARC, Mumbai, India

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics
The Proton Improvement Plan, Stage Two (PIP-II) is a program of upgrades proposed for the Fermilab injection complex, which central part is an 800-MeV, 2-mA CW SRF linac. A prototype of the PIP-II linac front end called PIP-II Injector Test (PIP2IT) is being built at Fermilab. As of now, a 15-mA DC, 30-keV H⁻ ion source, a 2 m-long Low Energy Beam Transport (LEBT), a 2.1-MeV CW RFQ, followed by a 10-m Medium Energy Beam Transport (MEBT) have been assembled and commissioned. The MEBT bunch-by-bunch chopping system and the requirement of a low uncontrolled beam loss put stringent limitations on the beam envelope and its variation. Measurements of transverse and longitudinal beam dynamics in the MEBT were performed in the range of 1-10 mA of the RFQ beam current. Almost all measurements are made with 10 μs beam pulses in order to avoid damage to the beam line. This report presents measurements of the transverse optics with differential trajectories, reconstruction of the beam envelope with scrapers and an Allison emittance scanner, as well as bunch length measurements with a Fast Faraday Cup.

Slides MOP1WB03 [3.750 MB]

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MOP2WB02

Simulation and Measurement Campaigns for Characterization and Performance Improvement of the CERN Heavy Ion Linac3

linac, simulation, extraction, rfq

64

G. Bellodi, S. Benedetti, D. Küchler, F.J.C. Wenander
CERN, Geneva, Switzerland
V. Toivanen
GANIL, Caen, France

In the framework of the LHC Injector Upgrade programme (LIU), several activities have been carried out to improve the GTS-LHC ion source and Linac3 performance (Linac3 providing the charged heavy ion beams for CERN exper-iments). A restudy of the beam dynamics and transport through the linac was initiated, through a campaign of systematic machine measurements and parallel beam simulations, generalising techniques developed for beam characterization during Linac4 commissioning. The work here presented will review the most relevant findings and lessons learnt in the process.

Slides MOP2WB02 [17.512 MB]

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MOP2WB03

Emittance Growth and Beam Losses in LANSCE Linear Accelerator

beam-losses, proton, DTL, linac

70

Y.K. Batygin, R.W. Garnett, L. Rybarcyk
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396.
The LANSCE Accelerator facility currently utilizes four 800 MeV H⁻ beams and one 100 MeV proton beam. Multi-beam operation requires careful control of accelerator tune to minimize beam losses. The most powerful 80 kW H⁻ beam is accumulated in the Proton Storage Ring and is extracted to the Lujan Neutron Scattering Center facility for production of moderated neutrons with meV-keV energy. Another H⁻ beam is delivered to the Weapon Neutron Research facility to create un-moderated neutrons in the keV - MeV energy range. The third H⁻ beam is shared between the Proton Radiography Facility and the Ultra-Cold Neutron facility. The 23 kW proton beam is used for isotope production in the fields of medicine, nuclear physics, national security, environmental science and industry. Minimization of beam losses in the linac is achieved due to careful tuning of the beam in each section of the accelerator facility, imposing restrictions on amplitudes and phases of RF sections, control of H⁻ beam stripping, and optimization of ion sources operation. This paper summarizes experimental results in accelerator operations and categorizes various sources of emittance growth and beam losses.

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TUA1WC01

Installation and Commissioning of the Upgraded SARAF 4-rods RFQ

rfq, operation, proton, linac

75

L. Weissman, D. Berkovits, B. Kaizer, J. Luner, D. Nusbaum, A. Perry, J. Rodnizki, A. Shor, I. Silverman
Soreq NRC, Yavne, Israel
A. Bechtold
NTG Neue Technologien GmbH & Co KG, Gelnhausen, Germany

Acceleration of a 1mA Continuous Wave (CW) deuteron (A/Q=2) beam at SARAF has been accomplished for the first time. A 5.3 mA pulsed deuteron beam has been accelerated as well. These achievements cap a series of major modifications to the Radio Frequency Quadrupole (RFQ) 4-rods structure which included the incorporation of a new end flange, introduction of an additional RF power coupler and, most recently, installation of a new set of rod electrodes. The new rod modulation has been designed to enable deuteron beam acceleration at a lower inter-electrode voltage, to a slightly reduced final energy of 1.27 MeV/u and with stringent constraints on the extant of beam tails in the longitudinal phase space. This report will focus primarily on the installation and testing of the new rods. The successful conditioning campaign to 200 kW, ~10% above than the working point for deuteron operation, will be described. Beam commissioning with proton and deuteron beams will also be detailed. Results of beam measurements will be presented, including the characterization of the output beam in the transverse and longitudinal phase space. Finally, future possible improvements are discussed.

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TUA2WC03

Studies on Superconducting Deuteron Driver Linac for BISOL

cavity, linac, ISOL, SRF

88

F. Zhu, M. Chen, A.Q. Cheng, J.K. Hao, H.P. Li, S.W. Quan, F. Wang
PKU, Beijing, People's Republic of China

Funding: Work supported by National Basic Research Project (No. 2014CB845504)
Beijing isotope separation on line type rare ion beam facility (BISOL) for both basic science and applications is a project proposed by China Institute of Atomic Energy and Peking University. Deuteron driver accelerator of BISOL would adopt superconducting half wave resonators (HWRs) with low beta and high current. The HWR cavity performance and the beam dynamic simulation of the superconducting deuteron driver accelerator will be presented in this paper.

Slides TUA2WC03 [10.028 MB]

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TUP1WA03

Beam Instabilities After Injection to the LHC

injection, simulation, controls, operation

163

H. Timko, T. Argyropoulos, I. Karpov, E.N. Shaposhnikova
CERN, Geneva, Switzerland

Long-lasting phase oscillations have been observed at injection into the LHC since its first start-up with beam. These oscillations, however, were not leading to noticeable losses or blow-up in operation, and were therefore not studied in detail. In 2017, dedicated measurements with high-intensity bunches revealed that oscillations can lead to losses even slightly below the baseline intensity for the high-luminosity upgrade of the LHC. For the first time, high-resolution bunch profile acquisitions were triggered directly at injection and the formation of large-amplitude non-rigid dipole oscillations was observed on a turn-by-turn basis. First simulations can reproduce this instability via bunch filamentation that takes place after injection, depending on the mismatch between the bunch and bucket size in momentum at injection.

Slides TUP1WA03 [2.166 MB]

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TUP2WA02

Momentum Slip-Stacking Simulations for CERN SPS Ion Beams with Collective Effects

simulation, flattop, ECR, cavity

174

D. Quartullo, T. Argyropoulos, A. Lasheen
CERN, Geneva, Switzerland

The LHC Injectors Upgrade (LIU) Project at CERN aims at doubling the total intensity of the Pb-ion beam for the High-Luminosity LHC (HL-LHC) project. This goal can be achieved by using momentum slip-stacking (MSS) in the SPS, the LHC injector. This RF gymnastics, originally proposed to increase bunch intensity, will be used on the intermediate energy plateau to interleave two batches, reducing the bunch spacing from 100 to 50 ns. The MSS feasibility can be tested only in 2021, after the beam controls upgrade of the SPS 200 MHz RF system, so beam dynamics simulations are used to design this complicated beam manipulation. Simulations of the MSS were performed using the CERN BLonD code with a full SPS impedance model. Attention has been paid to the choice of the RF and machine parameters (beam energy, time duration, RF frequency and voltage programmes) to reduce losses and the final bunch length which is crucial for the injection into the LHC 400 MHz buckets. The initial beam parameters used in simulations were obtained from beam measurements in the first part of the SPS cycle taking into account bunch-by-bunch losses on flat bottom and development of bunch instabilities.

Slides TUP2WA02 [8.272 MB]

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WEA2WB02

Recent Studies of Beam Physics for Ion Linacs

DTL, injection, cavity, linac

200

L. Groening, S. Appel, X. Du, P. Gerhard, M.T. Maier, A. Rubin, P. Scharrer, H. Vormann, C. Xiao
GSI, Darmstadt, Germany
M. Chung
UNIST, Ulsan, Republic of Korea
P. Scharrer
HIM, Mainz, Germany
P. Scharrer
Mainz University, Mainz, Germany

The UNIversal Linear ACcelerator (UNILAC) at GSI aims at provision of high brilliant ion beams, as it main purpose will be to serve as injector for the upcoming FAIR accelerator complex. The UNILAC injects into the subsequent synchrotron SIS18 applying horizontal multi-turn injection (MTI). Optimization of this process triggered intense theoretical and experimental studies of dynamics of transversely coupled beams. These activities comprise round-to-flat beam transformation, full 4d transverse beam diagnostics, optimization of the MTI parameters through generic algorithms, and extension of Busch's theorem to accelerated particle beams. Finally, recent advance in modeling time-transition-factors and its impact on improved linac performance will be presented as well as progress in the optimization of ion charge state stripping.

Slides WEA2WB02 [4.772 MB]

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WEP1WB02

Beam Dynamics Simulation and Measurements for the IFMIF/EVEDA Project

rfq, simulation, space-charge, proton

210

M. Comunian, L. Antoniazzi, A. Baldo, C. Baltador, L. Bellan, D. Bortolato, M. Cavenago, E. Fagotti, M.G. Giacchini, F. Grespan, M. Montis, A. Palmieri, A. Pisent, F. Scantamburlo
INFN/LNL, Legnaro (PD), Italy
L. Bellan
Univ. degli Studi di Padova, Padova, Italy
N. Chauvin
IRFU, CEA, University Paris-Saclay, Gif-sur-Yvette, France
H. Dzitko
F4E, Germany

In the framework of IFMIF/EVEDA project the source and RFQ are ready to be tested with beam. In this article the beam dynamics simulation and the measurement performed in preparation of the first beam injection are presented. The installed line is composed by the proton and deuteron Source with the LEBT composed of two solenoids that inject in the 10 meters long RFQ, the MEBT, diagnostic plate and the beam dump. The line is prepared to be tested with protons of 8 mA in pulsed mode (up to 0.1%).

Slides WEP1WB02 [10.303 MB]

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WEP1WB03

First Heavy Ion Beam Acceleration with a Superconducting Multi Gap CH-cavity

cavity, linac, heavy-ion, acceleration

215

W.A. Barth, M. Heilmann, A. Rubin, A. Schnase, S. Yaramyshev
GSI, Darmstadt, Germany
K. Aulenbacher, W.A. Barth, F.D. Dziuba, V. Gettmann, T. Kürzeder, M. Miski-Oglu
HIM, Mainz, Germany
K. Aulenbacher
IKP, Mainz, Germany
M. Basten, M. Busch, H. Podlech, M. Schwarz
IAP, Frankfurt am Main, Germany

A newly developed superconducting 15-gap RF-cavity has been successfully tested at GSI Helmholtzzentrum für Schwerionenforschung. After a short commissioning and ramp up time of some days, a Crossbar H-cavity accelerated first time heavy ion beams with full transmission up to the design beam energy of 1.85 MeV/u. The design acceleration gain of 3.5 MV inside a length of less than 70 cm has been verified with heavy ion beam of up to 1.5 particle mueA. The measured beam parameters showed excellent beam quality, while a dedicated beam dynamics layout provides beam energy variation between 1.2 and 2.2 MeV/u. The beam commissioning is a milestone of the R&D work of Helmholtz Institute Mainz and GSI in collaboration with Goethe University Frankfurt towards a superconducting heavy ion continuous wave linear accelerator cw-Linac with variable beam energy. Further linac beam dynamics layout issues will be presented as well.

Slides WEP1WB03 [20.157 MB]

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WEA1WA02

Approaching the High-Intensity Frontier Using the Multi-Turn Extraction at the CERN Proton Synchrotron

extraction, proton, operation, synchrotron

231

A. Huschauer, H. Bartosik, S. Cettour-Cave, M. R. Coly, D.G. Cotte, H. Damerau, G.P. Di Giovanni, S.S. Gilardoni, M. Giovannozzi, V. Kain, E. Koukovini-Platia, B. Mikulec, G. Sterbini, F. Tecker
CERN, Geneva, Switzerland

Complementary to the physics research at the LHC, several fixed target facilities receive beams from the LHC injector complex. In the scope of the fixed target physics program at the Super Proton Synchrotron, high-intensity proton beams from the Proton Synchrotron are extracted using the Multi-Turn Extraction scheme, which is based on particle trapping in stable islands of the horizontal phase space. Considering the number of protons requested by future experimental fixed target facilities, such as the Search for Hidden Particles experiment, the currently operationally delivered beam intensities are insufficient. Therefore, experimental studies have been conducted to optimize the Multi-Turn Extraction technique and to exploit the possible intensity reach. The results of these studies along with the operational performance of high-intensity beams during the 2017 run are presented in this paper. Furthermore, the impact of the hardware changes pursued in the framework of the LHC Injectors Upgrade project on the high-intensity beam properties is briefly mentioned.

Slides WEA1WA02 [25.566 MB]

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WEA2WA01

High Intensity Effects of Fixed Target Beams in the CERN Injector Complex

impedance, simulation, space-charge, proton

237

E. Koukovini-Platia, H. Bartosik, M. Migliorati, G. Rumolo
CERN, Geneva, Switzerland
M. Migliorati
INFN-Roma1, Rome, Italy
M. Migliorati
Sapienza University of Rome, Rome, Italy

The current fixed target (FT) experiments at CERN are a complementary approach to the Large Hadron Collider (LHC) and play a crucial role in the investigation of fundamental questions in particle physics. Within the scope of the LHC Injectors Upgrade (LIU), aiming to improve the LHC beam production, the injector complex will be significantly upgraded during the second Long Shutdown (LS2). All non-LHC beams are expected to benefit from these upgrades. In this paper, we focus on the studies of the transverse instability in the Proton Synchrotron (PS), currently limiting the intensity of Time-Of-Flight (ToF) type beams, as well as the prediction of the impact of envisaged hardware modifications. A first discussion on the effect of space charge on the observed instability is also being presented.

Slides WEA2WA01 [2.483 MB]

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WEP1WA03

IBS Near Transition Crossing in NICA Collider

collider, optics, lattice, focusing

252

S.A. Kostromin, A.O. Sidorin
JINR, Dubna, Moscow Region, Russia
I.V. Gorelyshev
JINR/VBLHEP, Dubna, Moscow region, Russia
V.A. Lebedev
Fermilab, Batavia, Illinois, USA
A.O. Sidorin
Saint Petersburg State University, Saint Petersburg, Russia

Intrabeam scattering (IBS) of charged particles in a particle beam results in an exchange of energy between different degrees of freedom. That results in an increase of average energy of particles in the beam frame and an increase of the 3D-emittance. The paper considers calculations of beam emittance growth rates for different options of NICA collider and IBS effects in close vicinity of the transition.

Slides WEP1WA03 [1.774 MB]

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WEP2PO006

Overview of the CERN PSB-to-PS Transfer Line Optics Matching Studies in View of the LHC Injectors Upgrade Project

optics, operation, injection, quadrupole

272

V. Forte, S.C.P. Albright, W. Bartmann, G.P. Di Giovanni, M.A. Fraser, C. Heßler, A. Huschauer, A. Oeftiger
CERN, Geneva, Switzerland

At injection into the CERN Proton Synchrotron (PS) a significant horizontal emittance blow-up of the present high brightness beams for the LHC is observed. A partial contribution to this effect is suspected to be an important mismatch between the dispersion function in the transfer line from the PS Booster (PSB) and the ring itself. This mismatch will be unacceptable in view of the beam parameters requested by the LHC Injectors Upgrade (LIU) project with high longitudinal emittance and momentum spread. To deliver the requested beam parameters the PSB-to-PS transfer line will be upgraded and the optics in the line changed to improve the matching from all the four PSB rings. A re-matching campaign from the PSB ring 3 has been carried out to evaluate the impact of the present optics mismatch as a source of emittance growth both in simulations and measurements.

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WEP2PO007

Multi-Particle Simulations of the Future CERN PSB Injection Process with Updated Linac4 Beam Performance

injection, linac, optics, simulation

278

V. Forte, C. Bracco, G.P. Di Giovanni, M.A. Fraser, A.M. Lombardi, B. Mikulec
CERN, Geneva, Switzerland

In the framework of the LHC Injectors Upgrade (LIU) project, the injection process in the CERN Proton Synchrotron Booster (PSB) will be renovated after the connection with the Linac4. A new H⁻ charge exchange injection system using a stripping foil is foreseen to increase the brightness of the stored beams and to provide high flexibility in terms of emittance tailoring at 160 MeV. Realistic multi-particle simulations of the future injection processes for high brightness beams (i.e. for the LHC) and high intensity beams (i.e. for the ISOLDE experiment) are presented in this paper. The simulations are based on the present performance of Linac4 and include scattering induced by the foil, space charge effects and compensation of the lattice perturbation introduced by the bumpers of the injection chicane.

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WEP2PO011

Studies of Transverse Instabilities in the CERN SPS

simulation, octupole, optics, injection

291

M.S. Beck, H. Bartosik, M. Carlà, K.S.B. Li, G. Rumolo, M. Schenk
CERN, Geneva, Switzerland
U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

In the framework of the LHC Injectors Upgrade (LIU), beams with about twice the intensity compared to the present values will have to be accelerated by the CERN Super Proton Synchrotron (SPS) and extracted towards the Large Hadron Collider (LHC). Machine studies with intensity higher than the nominal LHC beam have shown that coherent instabilities in both transverse planes may develop at injection energy, potentially becoming a limitation for the future high intensity operation. In particular, a transverse mode coupling instability is encountered in the vertical plane, the threshold of which can be sufficiently increased by changing the machine optics. In addition, a headtail instability of individual bunches is observed in the horizontal plane in multi-bunch operation, which requires stabilization by high chromaticity. The PyHEADTAIL code has been used to check if the present SPS impedance model reproduces the experimental observations. The instability growth rates have been studied for different machine optics configurations and different chromaticity settings. Other stabilizing mechanisms like tune spread from octupoles or the transverse damper have also been investigated.

Poster WEP2PO011 [4.940 MB]

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WEP2PO027

Simulation of the Axial Injection Beam Line of the Reconstructed U200 Cyclotron of FLNR JINR

cyclotron, solenoid, ECR, injection

319

N.Yu. Kazarinov, J. Franko, G.G. Gulbekyan, I.A. Ivanenko, I.V. Kalagin
JINR, Dubna, Moscow Region, Russia

Flerov Laboratory of Nuclear Reaction of Joint Institute for Nuclear Research begin the works under reconstruction of the cyclotron U200. The reconstructed cyclotron is intended for acceleration of heavy ions with mass-to-charge ratio A/Z within interval from 5 to 8 up to the fixed energies 3.5 and 5.3 MeV per unit mass. The intensity of the accelerated ions will be about 3 pmcA for lighter ions (A< 40) and about 0.3 pmcA for heavier ions (A<132). The cyclotron will be used in the microchip testing, production of the track pore membranes and for applied physics. The injection into cyclotron will be realized from the external superconducting ECR ion source. The simulation of the axial injection system of the cyclotron is presented in this report.

Poster WEP2PO027 [0.679 MB]

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THA1WD04

High-Brightness Challenges for the Operation of the CERN Injector Complex

injection, linac, brightness, proton

352

K. Hanke, S.C.P. Albright, R. Alemany-Fernández, H. Bartosik, E. Chapochnikova, H. Damerau, G.P. Di Giovanni, B. Goddard, A. Huschauer, V. Kain, A. Lasheen, M. Meddahi, B. Mikulec, G. Rumolo, R. Scrivens, F. Tecker
CERN, Geneva, Switzerland

CERN's LHC injectors are delivering high-brightness proton and ion beams for the Large Hadron Collider LHC. We review the present operation modes and beam performance, and highlight the limitations. We will then give an overview of the upgrade program that has been put in place to meet the demands of the LHC during the High-Luminosity LHC era.

Slides THA1WD04 [4.746 MB]

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THA2WD01

Operation Challenges and Performance of the LHC During Run II

luminosity, MMI, operation, brightness

357

R. Steerenberg, J. Wenninger
CERN, Geneva, Switzerland

The CERN Large Hadron Collider Run II saw an important increase in beam performance through both, improvements in the LHC and an increased beam brightness from the injectors, leading to a peak luminosity that exceeds the LHC design luminosity by more than a factor two. This contribution will give an overview of run 2, the main challenges encountered and it will address the measures applied to deal with and make use of the increased beam brightness. Finally potential areas where further performance improvement can be a realized will be identified.

Slides THA2WD01 [6.709 MB]

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THP1WB01

Commissioning Status of Linear IFMIF Prototype Accelerator (LIPAc)

rfq, MMI, acceleration, cavity

366

A. Kasugai, T. Akagi, T. Ebisawa, Y. Hirata, R. Ichimiya, K. Kondo, S. Maebara, K. Sakamoto, T. Shinya, M. Sugimoto
QST, Aomori, Japan
P. Abbon, N. Bazin, B. Bolzon, N. Chauvin, S. Chel, R. Gobin, J. Marroncle, B. Renard
CEA/DSM/IRFU, France
L. Antoniazzi, L. Bellan, D. Bortolato, M. Comunian, E. Fagotti, F. Grespan, M. Montis, A. Palmieri, A. Pisent
INFN/LNL, Legnaro (PD), Italy
P.-Y. Beauvais, H. Dzitko, D. Gex, A. Jokinen, G. Phillips
F4E, Germany
P. Cara, R. Heidinger, I. Moya
Fusion for Energy, Garching, Germany
D. Jiménez-Rey, I. Kirpitchev, J. Mollá, P. Méndez, I. Podadera, D. Regidor, M. Weber, C. de la Morena
CIEMAT, Madrid, Spain
J. Knaster, A. Marqueta, G. Pruneri, F. Scantamburlo
IFMIF/EVEDA, Rokkasho, Japan

The IFMIF project aiming at material tests for a future fusion DEMO reactor is under the EVEDA phase in the BA Agreement of fusion program between Japan and EU. As the accelerator activity, the installation and commissioning of the Linear IFMIF Prototype Accelerator (LIPAc) is at the second stage of demonstration of the feasibility of the low energy section of an IFMIF deuteron accelerator up to 9 MeV with a beam current of 125 mA, CW. The installation of injector, RFQ, MEBT, D-Plate and LPBD for LIPAc with 8 coaxial high-power transmission lines and RF power system was just done in 2017 at Rokkasho, Japan. After that, the RF conditioning of RFQ for beam commissioning is underway. The beam commissioning of RFQ with H⁺/D⁺ and the acceleration demonstration up to 5 MeV-125 mA-0.1% duty cycle with D⁺ will be done.

Slides THP1WB01 [13.177 MB]

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THP2WB01

Revisiting the Longitudinal 90 Degree Limit for Superconducting Linear Accelerators

space-charge, lattice, resonance, focusing

369

I. Hofmann
GSI, Darmstadt, Germany
I. Hofmann
TEMF, TU Darmstadt, Darmstadt, Germany

In the design of high-intensity linear accelerators one of the generally adopted criteria is not to exceed a zero-current phase advance per focusing period of 90 degrees in order to avoid the space charge driven envelope instability, or a coinciding fourth order space charge resonance. Recently it was claimed that in certain structures, predominantly applicable to super-conducting linac lattices - such a constraint is not always necessary in the longitudinal plane (I. Hofmann and O. Boine-Frankenheim, Phys. Rev. Lett. 118, 2017). This applies primarily to such focusing structures, where the transverse focusing period only induces a weak space charge dependent modulation in the longitudinal plane, and a different periodicity is applicable to the longitudinal plane. Hence the longitudinal 90 degree stopband is practically absent, and phase advances significantly above 90 degrees should be possible in such structures, with a corresponding additional design freedom. As a consequence, we suggest that the 90 degree rule should no longer be taken as standard criterion in the longitudinal plane of linac design.

Slides THP2WB01 [5.179 MB]

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THP2WB02

High-Intensity Beam Dynamics Simulation of the IFMIF-like Accelerators

simulation, space-charge, beam-transport, rfq

373

S.H. Moon, M. Chung
UNIST, Ulsan, Republic of Korea

Funding: This research was supported by the National Research Foundation of Korea (Grant No. NRF-2017M1A7A1A02016413).
The IFMIF (International Fusion Material Irradiation Facility) project is being considered to build fusion material test facility. The IFMIF will use two accelerators to generate high energy neutrons. However, the IFMIF accelerators have been designed to have much higher beam power and beam current than the existing accelerators, so space charge effect is very strong. This raises big concerns about beam loss and beam transport stability, thus detailed high-intensity beam dynamics study of the IFMIF-like accelerators is indispensable. This research aims to perform source to target simulation of the IFMIF-like accelerator. The simulation has been carried out by two different kinds of simulation codes because the IFMIF accelerator has distinctive features. One is TRACEWIN simulation code which was used in IFMIF initial design. The other is WARP 3D PIC code which can precisely calculate space charge effects. This presentation will focus on beam simulations for LEBT, RFQ, and MEBT of the IFMIF accelerator

Slides THP2WB02 [10.583 MB]

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THA1WE02

Requirements and Results for Quadrupole Mode Measurements

space-charge, synchrotron, quadrupole, pick-up

393

A. Oeftiger
CERN, Geneva, Switzerland

Funding: Research supported by the HL-LHC project.
Direct space charge may be quantified, and hence the beam brightness observed, by measuring the quadrupolar beam modes in the CERN Proton Synchrotron (PS). The spectrum of the transverse beam size oscillations (i.e. the quadrupolar beam moment) contains valuable information: the betatron envelope modes and the coherent dispersive mode indicate optics mismatch, while their frequency shifts due to space charge allow a direct measurement thereof. To measure the quadrupolar beam moment we use the Base-Band Q-meter system of the PS which is based on a four electrode stripline pick-up. Past experiments with quadrupolar pick-ups often investigated coasting beams, where the coherent betatron and dispersion modes correspond to single peaks in the tune spectrum. In contrast, long bunched beams feature bands of betatron modes: the mode frequencies shift depending on the transverse space charge strength which varies with the local line charge density. By using the new transverse feedback in the PS as a quadrupolar RF exciter, we measured the quadrupolar beam transfer function. The beam response reveals the distinct band structure of the envelope modes as well as the coherent dispersive mode.

Slides THA1WE02 [7.315 MB]

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THA1WE03

BPM Technologies for Quadrupolar Moment Measurements

pick-up, factory, multipole, electron

399

A. Sounas, M. Gąsior, T. Lefèvre
CERN, Geneva, Switzerland

Quadrupolar moment measurements based on electromagnetic pick-ups (PU), like BPMs, have attracted particular interest as non-intercepting diagnostics to determine the transverse beam size. Here, the second-order moment, which contains information about the beam size, is extracted from the BPM electrode signals. Despite the simplicity of the concept, quadrupololar measurements have always been challenging in practice. This is related to the fact that the quadrupolar moment constitutes only a very small part of the total PU signal, which is dominated by the contributions of beam intensity and position. In this study we discuss the limitations of absolute quadrupolar measurements if applying traditional BPM technologies, and we propose a new approach to efficiently overcome them via movable PUs. Moreover, we highlight the potential use of BPMs as an emittance measurement system during the energy ramp at synchrotrons by performing differential quadrupolar measurements, which show a remarkably higher accuracy than absolute measurements. Dedicated studies using different types of BPMs in the Large Hadron Collider (LHC) at CERN demonstrated promising results.

Slides THA1WE03 [5.299 MB]

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THP2WC02

LLRF Studies for HL-LHC Crab Cavities

cavity, feedback, luminosity, betatron

440

P. Baudrenghien
CERN, Geneva, Switzerland
T. Mastoridis
CalPoly, San Luis Obispo, California, USA

The HL-LHC upgrade includes sixteen Crab Cavities (CC) to be installed on both sides of the high luminosity experiments, ATLAS and CMS. Two issues have been highlighted for the Low Level RF: transverse emittance growth (and associated luminosity drop) caused by CC RF noise, and large collimator losses following a CC trip. A prototype cryomodule with two CCs has been installed in the SPS, and tests have started in May 2018 with beam. This paper briefly reports on preliminary results from the SPS tests. It then presents emittance growth calculations from cavity field phase and amplitude noise, deduces the maximum RF noise compatible with the specifications and presents a possible cure consisting of a feedback on CC phase and amplitude. To reduce the losses following a CC trip we propose to implement transverse tail cleaning via the injection of CC noise with an optimized spectrum, which selectively excites the particles of large transverse oscillation amplitudes.

Slides THP2WC02 [1.943 MB]

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