IPAC2018 - List of Keywords (kicker)

Paper	Title	Other Keywords	Page
MOPMF062	Upgrade of the Dilution System for HL-LHC	operation, Windows, damping, simulation	261
	C. Wiesner, W. Bartmann, C. Bracco, M. Calviani, E. Carlier, L. Ducimetière, M.I. Frankl, M.A. Fraser, S.S. Gilardoni, B. Goddard, T. Kramer, A. Lechner, N. Magnin, A. Perillo-Marcone, T. Polzin, E. Renner, V. Senaj CERN, Geneva, Switzerland
	The LHC Beam Dump System is one of the most critical systems for reliable and safe operation of the LHC. A dedicated dilution system is required to sweep the beam over the front face of the graphite dump core in order to reduce the deposited energy density. The High Luminosity Large Hadron Collider (HL-LHC) project foresees to increase the total beam intensity in the ring by nearly a factor of two, resulting in a correspondingly higher energy deposition in the dump core. In this paper, the beam sweep pattern and energy deposition for the case of normal dilution as well as for the relevant failure cases are presented. The implications as well as possible mitigations and upgrade measures for the dilution system, such as decreasing the pulse-generator voltage, adding two additional kickers, and implementing a retrigger system, are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF062
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MOPMK015	Development of a Bunched-Beam Electron Cooler for the Jefferson Lab Electron-Ion Collider	electron, linac, gun, cathode	382
	S.V. Benson, Y.S. Derbenev, D. Douglas, F.E. Hannon, A. Hutton, R. Li, R.A. Rimmer, Y. Roblin, C. Tennant, H. Wang, H. Zhang, Y. Zhang JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S.DOE Contract No. DE-AC05-06OR23177. Jefferson Lab is in the process of designing an electron-ion collider with unprecedented luminosity at a 65 GeV center-of-mass energy. This luminosity relies on ion cooling in both the booster and the storage ring of the accelerator complex. The cooling in the booster will use a conventional DC cooler similar to the one at COSY. The high-energy storage ring, operating at a momentum of up to 100 GeV/nucleon, requires novel use of bunched-beam cooling. We will present a new design for a Circulator Cooler Ring for bunched-beam electron cooling. This requires the generation and transport of very high-charge magnetized bunches, acceleration of the bunches in an energy recovery linac, and transfer of these bunches to a circulating ring that passes the bunches 11 times through the proton or ion beam inside cooling solenoids. This design requires the suppression of the effects of space charge and coherent synchrotron radiation using shielding and RF compensation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMK015
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MOPML025	Slow Extraction Optimization at the MedAustron Ion Therapy Center: Implementation of Front End Acceleration and RF Knock Out	extraction, proton, acceleration, synchrotron	453
	A. De Franco, L. Adler, F. Farinon, N. Gambino, G. Guidoboni, G. Kowarik, M. Kronberger, C. Kurfürst, S. Myalski, S. Nowak, M.T.F. Pivi, C. Schmitzer, I. Strašík, P. Urschütz, A. Wastl EBG MedAustron, Wr. Neustadt, Austria L.C. Penescu Abstract Landscapes, Montpellier, France
	Funding: This project has received funding from the European Union's Horizon 2020 research and Innovation programme under the Marie Skłodowska-Curie grant agreement No 675265. MedAustron is a synchrotron-based ion therapy center allowing tumour treatment with protons and other light ion species, in particular C⁶⁺. Commissioning of all fixed lines, two horizontal and one vertical, has been completed for protons and in parallel to the commissioning of a gantry and C⁶⁺, a facility upgrade study is progressing. The upgrade study encompasses the optimization of the slow extraction mechanism by employing the RF empty bucket channeling and RF Knock Out techniques. The former is a front end acceleration technique that suppress spill ripples, fundamental to safely operate the machine at the highest intensities. The latter is an alternative extraction technique which opens up interesting possibilities for fast beam energy and intensity modulations. In this work, we quantify spill smoothening effect achieved with the first and report the results of a feasibility study of the second using a Schottky monitor as a transverse kicker.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML025
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MOPML030	Demonstration of a Tunable Electron Beam Chopper for Application in 200 kV stroboscopic TEM	electron, laser, experiment, controls	467
	C.-J. Jing, S.V. Baryshev, A. Kanareykin, A. Liu, Y. Zhao Euclid TechLabs, LLC, Solon, Ohio, USA J.W. Lau NIST, Gaithersburg, Maryland, USA D. Masiel, B. Reed Integrated Dynamic Electron Solutions, Pleasanton, California, USA Y. Zhu BNL, Upton, Long Island, New York, USA
	Funding: The project is supported by the Office of Basic Energy Science of DOE through a Small Business Innovative Research grant #DE-SC0013121. For the last several decades, time-resolved transmission electron microscopes (TEM) exploring the sub-microsecond timescale have relied on the photoemission technology to generate the single or train of electron bunches. However, the complexity of additional laser system and the availability of high repitition rate laser limit applications of the laser-driven approach. Lately we have made substantial progress towards pioneering a new kind of time-resolved TEM, complementary to the existing laser-based techniques. Using a tunable RF beam-chopper, we are able to retrofit an exsiting TEM providing a pulsed electron beam at a continuously tunable reptition rate up to 12GHz and a tunable bunch length. In the article we will briefly discuss the working principle and experimental progress to date.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML030
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TUXGBF3	Reduction of the Kicker Impedance Maintaining the Performance of Present Kicker Magnet at RCS in J-PARC	impedance, simulation, synchrotron, extraction	616
	Y. Shobuda, Y. Irie, T. Takayanagi, T. Togashi, K. Yamamoto, M. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The present kicker at RCS in J-PARC is designed to make a waveform by superposing the forward and backward currents from the power source to extract beams, so that one terminal of the kicker is shorted and the other one is open. On the other hand, the kicker impedance is the dominant source of the beam instability at the RCS. This report proposes a scheme to reduce the kicker impedance, maintaining the beneficial of the superposition of currents with the present kicker magnet.
	Slides TUXGBF3 [9.947 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUXGBF3
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TUPAF027	CERN PS Kicker for Proton Injection: from Beam-Based Waveform Measurements to Hardware Improvements	simulation, injection, emittance, flattop	732
	V. Forte, A. Ferrero Colomo, M.A. Fraser, T. Kramer CERN, Geneva, Switzerland
	For 2017 operation, the termination mode of the CERN Proton Synchrotron (PS) horizontal injection kicker was permanently changed to short-circuited, to be compliant with the future performances requested by the LHC Injectors Upgrade (LIU) project. An extensive campaign of measurements was performed through a dedicated beam-based technique. The measurements identified possibilities for optimisation of the kicker system and were fundamental to properly tune the PSpice simulation model of the kicker, as well as for validating the hardware changes. The model was finally used to estimate the horizontal emittance growth for the future injection schemes in the PS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF027
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TUPAF028	Energy Deposition Studies and Analysis of the Quench Behavior in the Case of Asynchronous Dumps During 6.5 TeV LHC Proton Beam Operation	simulation, superconducting-magnet, proton, quadrupole	736
	M.I. Frankl, W. Bartmann, M. Bednarek, C. Bracco, A. Lechner, A.P. Verweij, C. Wiesner, D. Wollmann CERN, Geneva, Switzerland
	The CERN LHC beam dumping system comprises a series of septa and fast-pulsed kicker magnets for extracting the stored proton beams to the external beam dumps. Different absorbers in the extraction region protect superconducting magnets and other machine elements in case of abnormal beam aborts, where bunches are swept across the machine aperture. During Run 2 of the LHC, controlled beam loss experiments were carried out at 6.5 TeV probing the particle leakage from protection devices under realistic operation conditions. This paper presents particle shower simulations analyzing the energy deposition in superconducting coils and assessing if the observed magnet quenches are compatible with the presently known quench limits.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF028
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TUPAF031	Beam Simulation Studies for the Upgrade of the SPS Beam Dumping System	simulation, dumping, operation, injection	747
	C. Heßler, W. Bartmann, E. Carlier, L. Ducimetière, B. Goddard, F.M. Velotti CERN, Geneva, Switzerland
	The SPS at CERN currently uses a beam dumping system that is installed in the long straight section 1 (LSS1) of the SPS. This system consists of two beam stopper blocks for low and high energy beams, as well as two vertical and three horizontal kicker magnets, which deflect and dilute the beam on the dumps. Within the frame of the LHC injector upgrade project (LIU) the beam dumping system will be relocated to long straight section 5 (LSS5) and upgraded with an additional vertical kicker, new main switches and a single new beam dump, which covers the full energy range. The impact of a possible increase of the vertical kicker rise time on the beam has been studied in simulations with MAD-X for the different optics in the SPS. Furthermore, the impact on the beam in failure scenarios such as the non-firing of one kicker has been investigated. The results of these studies will be presented and discussed in this paper. Operational mitigation methods to deal with an increased rise time will also be discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF031
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TUPAF058	Optimization of the FCC-hh Beam Extraction System Regarding Failure Avoidance and Mitigation	extraction, hardware, collider, septum	850
	E. Renner, M.J. Barnes, W. Bartmann, F. Burkart, E. Carlier, L. Ducimetière, B. Goddard, T. Kramer, A. Lechner, N. Magnin, V. Senaj, J.A. Uythoven, P. Van Trappen, C. Wiesner CERN, Geneva, Switzerland
	A core part of the Future Circular Collider (FCC) study is a high energy hadron-hadron collider with a circumference of nearly 100~km and a center of mass beam energy of 100~TeV. The energy stored in one beam at top energy is 8.3~GJ, more than 20 times that of the LHC beams. Due to the large damage potential of the FCC-hh beam, the design of the beam extraction system is dominated by machine protection considerations and the requirement of avoiding any material damage in case of an asynchronous beam dump. Erratic operation of one or more extraction kickers is a main contributor to asynchronous beam dumps. The presented study shows ways to reduce the probability and mitigate the impact of erratic kicker switching. Key proposals to achieve this include layout considerations, different hardware options and alternative reaction strategies in case of erratic extraction kicker occurrence. Based on these concepts, different solutions are evaluated and an optimized design for the FCC-hh extraction system is proposed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF058
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TUPAF059	Design and Evaluation of FCC-hh Injection Protection Schemes	injection, dipole, collider, collimation	854
	E. Renner, M.J. Barnes, W. Bartmann, C. Bracco, R. Bruce, F. Burkart, B. Goddard, A. Lechner, L.S. Stoel, F.M. Velotti, C. Wiesner, D. Woog CERN, Geneva, Switzerland
	The Future Circular Collider (FCC) study considers several injector scenarios for FCC-hh, the proposed 100~TeV centre of mass hadron collider located at CERN. The investigated options include amongst others to use the LHC at 3.3~TeV or a superconducting SPS at 1.3~TeV as a High Energy Booster (HEB). Due to the high energy of the injected proton beam and the short time constant of injection failures, a thorough consideration of potential failure cases is of major importance. Further attention has to be given to the fact that the injection is - as in LHC - located upstream of the side experiments. Failure scenarios are identified for both injector options, appropriate designs of injection protection schemes are proposed and first simulations are conducted to validate the protection efficiency.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF059
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TUPAF060	Injection and Dump Systems for a 13.5 TeV Hadron Synchrotron HE-LHC	injection, extraction, septum, experiment	858
	W. Bartmann, M.J. Barnes, L. Ducimetière, B. Goddard, M. Hofer, T. Kramer, A. Lechner, E. Renner, A. Sanz Ull, V. Senaj, L.S. Stoel, C. Wiesner CERN, Geneva, Switzerland
	One option for a future circular collider at CERN is to build a 13.5 TeV hadron synchrotron, or High Energy LHC (HE-LHC) in the LHC tunnel. Injection and dump systems will have to be upgraded to cope with the higher beam rigidity and increased damage potential of the beam. The required modifications of the beam transfer hardware are highlighted in view of technology advancements in the field of kicker switch technology. An optimised straight section optics is shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF060
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TUPAF076	Design of PIP-II Medium Energy Beam Transport	vacuum, SRF, linac, cryomodule	905
	A. Saini, C.M. Baffes, A.Z. Chen, V.A. Lebedev, L.R. Prost, A.V. Shemyakin Fermilab, Batavia, Illinois, USA
	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-II (PIP-II) is a proposed upgrade for the accelerator complex at Fermilab. The central piece of PIP-II is a superconducting radio frequency (SRF) 800 MeV linac capable of operating in both CW and pulse regimes. The PIP-II linac comprises a warm front-end that includes a H⁻ ion source capable of delivering 15-mA, 30-keV DC or pulsed beam, a Low Energy Beam Transport (LEBT), a 162.5 MHz, CW Radio-Frequency Quadrupole (RFQ) accelerating the ions to 2.1 MeV and, a 14-m Medium Energy Beam Transport (MEBT) before beam is injected into SRF part of the linac. This paper presents the PIP-II MEBT design and, discusses operational features and considerations that lead to existing optics design such as bunch by bunch chopping system, minimization of radiation coming to the warm front-end from the SRF linac using a concrete wall, a robust vacuum protection system etc.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF076
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TUPAF078	Recent Results of HESR Original Stochastic Cooling Tanks at COSY	pick-up, experiment, storage-ring, hardware	913
	R. Stassen, B. Breitkreutz, N. Shurkhno FZJ, Jülich, Germany
	The High Energy Storage Ring (HESR) of the FAIR project at GSI Darmstadt will be very important for different scientific programs due to the modularized start version of FAIR. Stochastic cooling together with barrier bucket operation will be the key component to fulfill the requirements of the different experiments. First pickup and first kicker of the HESR stochastic cooling system have been installed into the COSY accelerator at FZJ Jülich. COSY is well suited to test the performance of the HESR stochastic cooling hardware at different energies and variable particle numbers. The novel dedicated HESR-structures were already successfully tested at the Nuclotron in Dubna for longitudinal cooling and during a beam time 2017 for transverse cooling at COSY. The results of the last stochastic cooling beam time will be presented as well as the first use of GaN based amplifiers in a stochastic cooling system. The HESR needs fast transmission-lines between PU and KI. Beside air-filled coax-lines, optical hollow fiber-lines are very attractive. First results with such a hollow fiber used for the transverse signal path will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF078
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TUPAL068	The Development of a Nw Fast Harmonic Kicker for the JLEIC Circulator Cooling Ring	cavity, emittance, simulation, electron	1171
	G.-T. Park, F. Fors, J. Guo, R.A. Rimmer, H. Wang, S. Wang JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. After the first half-scale, 5 harmonic kicker cavity prototyping * for the JLEIC's CCR/ERL electron cooler and the beam dynamic simulation study of the 10-turn CCR *. The optimized circulation cooling turns has been changed to 11 and only 5 odd-harmonic modes from 86.6 MHz to 779.4 MHz plus a DC bias are needed for the harmonic RF kicker system. The new cavity design including the electromagnetic and thermal cooling optimization and its 11 turns beam bunch tracking simulation with the new numerology of RF deflecting voltages will be presented. Further design specifications for its RF harmonic drive and the broadband RF window, coupler and circulator component will be given for handling 5 kW of total RF power. Y, Huang, H. Wang et al., Physical Review Accelerators and Beams 19, 122001 (2016). ** Y. Huang, H. Wang et al., Physical Review Accelerators and Beams 19, 084201 (2016).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAL068
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TUZGBD2	Transverse and Longitudinal Bunch-by-Bunch Feedback for Storage Rings	feedback, timing, FPGA, damping	1198
	T. Nakamura JASRI/SPring-8, Hyogo-ken, Japan
	Digital bunch-by-bunch feedback systems for betatron and synchrotron oscillation are powerful tools for suppression of beam instabilities and are indispensable for stable operation of storage rings. This invited talk reviews the world activities on transvers and longitudinal bunch-by-bunch feedback for storage rings.
	Slides TUZGBD2 [15.900 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUZGBD2
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TUZGBD4	Impact of a Wideband Feedback Prototype System on TMCI in the SPS	feedback, optics, injection, emittance	1208
	W. Höfle, H. Bartosik, E.R. Bjørsvik, G. Kotzian, T.E. Levens, K.S.B. Li CERN, Geneva, Switzerland J.E. Dusatko, J.D. Fox, C.H. Rivetta SLAC, Menlo Park, California, USA O. Turgut Stanford University, Stanford, California, USA
	The transverse mode coupling instability (TMCI) in the SPS has been identified as one of the potential performance limitations for future high intensity LHC beams that will be required for the High Luminosity (HL)-LHC era and is being addressed by the LHC Injector Upgrade Project (LIU). A potential mitigation can be provided by wideband feedback systems with a frequency reach of about 1 GHz . For this reason, the development of a prototype system has been started in a CERN collaboration within the US-LARP framework in 2008. In this report we present latest experimental results in 2017 where this prototype system was used in single and multi-bunch studies. In particular, a successful mitigation against TMCI at injection could be demonstrated in single bunch studies.
	Slides TUZGBD4 [15.116 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUZGBD4
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TUZGBD5	Performance of Nanometre-Level Resolution Cavity Beam Position Monitors at ATF2	cavity, feedback, dipole, electron	1212
	T. Bromwich, D.R. Bett, N. Blaskovic Kraljevic, R.M. Bodenstein, P. Burrows, G.B. Christian, C. Perry, R.L. Ramjiawan JAI, Oxford, United Kingdom S. Araki, A. Aryshev, T. Tauchi, N. Terunuma KEK, Ibaraki, Japan P. Bambade, S. Wallon LAL, Orsay, France S.W. Jang Korea University Sejong Campus, Sejong, Republic of Korea
	A system of three low-Q cavity beam position monitors (BPMs), installed in the interaction point (IP) region of the Accelerator Test Facility (ATF2) at KEK, has been designed and optimised for nanometre-level beam position resolution. The BPMs are used to provide an input to a low-latency, intra-train beam position feedback system deployed in single-pass, multi-bunch mode with the aim of demonstrating intra-train beam stabilisation on electron bunches of charge ~1 nC separated in time by 280 ns. In 2016 the BPM resolution was demonstrated to be below 50 nm using the raw measured vertical positions at the three BPMs. New results will be presented utilising integrated sampling of the raw waveforms, improved BPM alignment and modified cavities to demonstrate a vertical position resolution on the order of 20 nm.
	Slides TUZGBD5 [8.557 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUZGBD5
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TUPMF014	Synchrotron Accumulation on Off-Energy Closed-Orbit with Anti-Septum or Nonlinear Kicker	injection, septum, accumulation, closed-orbit	1280
	Y.P. Sun ANL, Argonne, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Off-axis accumulation on off-energy closed-orbit (so-called synchrotron injection/accumulation) was studied and implemented in the 1990s for LEP at CERN. The idea of using pulsed multipole injection on off-energy closed-orbit was first proposed in 2014 and then developed for Swiss Light Source (SLS) upgrade in 2015. In 2017, the anti-septum was proposed for SLS upgrade injection. In this paper, two similar injection schemes are proposed which combine off-axis accumulation on off-energy closed-orbit (no betatron oscillations), with the anti-septum or pulsed nonlinear kicker schemes. Preliminary lattice solutions are developed for Advanced Photon Source upgrade (APS-U) where a special injection straight (with length of 5.8 m) is designed with horizontal dispersion of 0.15m. The impact on the ring emittance is relatively small. The injection elements are all placed in this injection straight, including 1 thin septum and 3 slow kickers (or 1 pulsed nonlinear kicker). No fast kickers are needed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF014
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TUPMF017	Transport Line Design and Injection Configuration Optimization for the Advanced Photon Source Upgrade	injection, septum, dipole, emittance	1287
	A. Xiao, M. Borland ANL, Argonne, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. On-axis swap-out injection was chosen for the Advanced Photon Source Upgrade (APS-U) to allow pushing the beam emittance to an extremely low value. The injection section configuration was optimized within a multi-dimensional parameter space and made consistent with up-to-date technical developments. The booster-to-storage ring (BTS) transport line was designed to bring the electron beam from the existing Booster to the new storage ring (SR). Due to various limitations, this new BTS line is twisted both horizontally and vertically when approaching the injection point, which introduces challenges in both geometrical and optical matching. This paper presents our simple solution to these issues. The coupling effect caused by the twisted BTS line is also discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF017
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TUPMF046	The Injection and Extraction Design of the Booster for the HEPS Project	injection, extraction, storage-ring, booster	1356
	Y.Y. Guo, J. Chen, Z. Duan, Y. Jiao, Y.M. Peng, G. Xu IHEP, Beijing, People's Republic of China
	The HEPS booster is a 1Hz electron synchrotron. It accelerates electron bunches from 500 MeV to final energy of 6 GeV. The vertical scheme was chosen for the injection and extraction system of the booster. What's more, an injection system from storage ring is required. The layout of the injection and extraction system were introduced in this paper. The parameter optimization and other considerations are presented in detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF046
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TUPMF053	Longitudinal Impedance Measurement of the Strip-Line Kicker for High Energy Photon Source (HEPS)	impedance, simulation, coupling, distributed	1379
	S.K. Tian, J. Chen, Y. Jiao, H. Shi, L. Wang, N. Wang IHEP, Beijing, People's Republic of China
	The High Energy Photon Source (HEPS) is a 6-GeV, kilometer-scale storage ring light source to be built in China. One of the main design challenges of the storage ring is to minimize collective instabilities associated with the impedance of small-aperture vacuum components. In this paper we present beam coupling impedance measurements obtained by the well known coaxial wire method, for the HEPS Strip-Line kicker. The frequency dependent real and imaginary parts of the distributed impedance are obtained from the measured S-parameters.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF053
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TUPMF084	Optimization of the Injection Kicker Bump Leakage at PETRA III	injection, septum, feedback, electron	1467
	J. Keil, G. Kube, F. Obier, G.K. Sahoo, R. Wanzenberg DESY, Hamburg, Germany
	PETRA III is a third generation synchrotron light source at DESY delivering high brightness photon beams for users at 21 beam lines. It is operated at 6 GeV with a beam current of 100 mA in top-up mode and is in operation for users since 2010. An off-axis injection scheme is used to accumulate beam from the booster synchrotron DESY II in PETRA III. Three fast injection kicker magnets generate a closed orbit bump for one turn to move the stored beam near to the injection septum magnet. Ideally the orbit bump generated by the 10 μs long half-sine pulses of the kickers should be closed. Due to differences in pulse shape as well as timing and amplitude errors of the pulses there is some leakage of the injection bump which disturbs the closed orbit and affects the beam quality during top-up operation. Turn-by-turn data from the beam position monitor (BPM) system of PETRA III have been used to measure the bump leakage for different bucket positions in the filling pattern. The procedure to reduce the injection kicker bump leakage and the achieved improvement will be discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF084
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TUPMK001	Removal of RF-Fingers at the Edges of the Injection Kickers	impedance, resonance, storage-ring, injection	1485
	T.F.G. Günzel, N. Ayala, F.F.B. Fernández, U. Iriso, M. Pont ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	The ALBA storage ring injection kickers are equipped with RF-fingers to close a 2.5 mm gap between the ceramic tube and the metallic flange. After two distortion incidents that required the replacement of the fingers, their removal was decided. The decision could be supported by the observation that most of the additional impedance is created above the cut-off frequency of the beam pipe. This was later confirmed by a temperature decrease in that zone after the removal. Furthermore it was checked that the thresholds of the longitudinal coupled bunch instabilities of modes trapped around the resulting open gap are above the maximal applied beam current of 400 mA.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMK001
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TUPMK004	Using Decoherence to Prevent Damage to the Swap-Out Dump for the APS Upgrade	simulation, emittance, electron, storage-ring	1494
	M. Borland, J.C. Dooling, R.R. Lindberg, V. Sajaev, A. Xiao ANL, Argonne, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. The Advanced Photon Source (APS) is pursuing an upgrade of the storage ring to a hybrid seven-bend-achromat* design, which will operate in swap-out mode. The ultra-low emittance (about 30 pm in both planes) combined with the desire to provide high charge (15 nC) in individual bunches, entails very high energy density in the beam. Simple estimates, confirmed by simulation, indicate that interaction of such a bunch with the dump material will result in localized melting. Over time, it is possible that the beam would drill through the dump and vent the ring vacuum. This would seem to prevent extraction and dumping of bunches as part of swap out, and also suggests that transferring of bunches out of the ring carries significant risk. We devised an idea for using a pre-kicker to cause decoherence of the target bunch emittances, making it safe to extract. Simulations show that the concept works very well. *L. Farvacque et al., IPAC13, 79 (2013).
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TUPML064	Staged Two Beam Acceleration Beam Line Design for the AWA Facility	experiment, gun, laser, acceleration	1688
	N.R. Neveu IIT, Chicago, Illinois, USA W. Gai, C.-J. Jing, J.G. Power ANL, Argonne, Illinois, USA C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA L.K. Spentzouris Illinois Institute of Technology, Chicago, Illinois, USA
	Funding: This work is funded by the DOE Office of Science, grant no. DE-SC0015479, and contract No. DE-AC02- 06CH11357. Two beam acceleration is a candidate for future high energy physics machines and FEL user facilities. This scheme consists of two independent electron beam lines operating synchronously. High-charge, 70 MeV drive bunch trains are injected from the RF photo-injector into decelerating structures to generate a few hundred of MW of RF power. This RF power is transferred through an RF waveguide to accelerating structures that are used to accelerate the witness beam. Staging refers to the sequential acceleration (energy gain) in two or more structures on the witness beam line. A kicker was incorporated on the drive beam line to accomplish a modular design so that each accelerating structure can be independently powered by a separate drive beam. Simulations were performed in OPAL-T to model the two beam lines. Beam sizes at the center of the structures was minimized to ensure good charge transmission. The resulting design will be the basis for proof of principle experiments that will take place at the Argonne Wakefield Accelerator (AWA) facility.
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WEXGBE1	Review of Top-up Injection Schemes for Electron Storage Rings	injection, synchrotron, septum, storage-ring	1745
	M. Aiba PSI, Villigen PSI, Switzerland
	Top-up operation, which nowadays is standard for lepton colliders and synchrotron light sources, has been developed over last decades. The accelerator performances have been drastically improved through top-up operation. However, future electron storage rings are designed, aiming at further high performance, to operate with strong nonlinear magnetic fields that may restrict their dynamic aperture. Consequently, the conventional off-axis injection and accumulation may become impossible. New injection schemes have been proposed and under development to overcome the difficulties and limitations expected in these machines. This paper reviews top-up injection schemes, including novel ideas recently proposed.
	Slides WEXGBE1 [3.584 MB]
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WEYGBF4	Development of a Solid-State Pulse Generator Driving Kicker Magnets for a Novel Injection System of a Low Emittance Storage Ring	injection, timing, high-voltage, storage-ring	1804
	T. Inagaki, H. Tanaka RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan H. Akikawa, K. Sato Nihon Koshuha Co. Ltd, Yokohama, Japan K. Fukami, C. Kondo, S. Takano Japan Synchrotron Radiation Research Institute (JASRI), RIKEN SPring-8 Center, Hyogo, Japan
	Funding: Funded by MEXT Japan A next generation electron storage ring represented by a diffraction-limited light source pursues an extremely low emittance leading to a small dynamic aperture and short beam lifetime. The top-up injection is hence indispensable to keep the stored beam current. The beam orbit fluctuation caused by the injection magnets should seriously obstruct utilization of an electron beam with sharp transverse profile. In order to solve these problems, a novel off-axis in-vacuum beam injection system was proposed. In the system, twin kicker magnets driven by a single solid-state pulsed power supply to launch a linear pi- bump orbit is the key to suppress the horizontal orbit fluctuation down to a level of several microns. Here, a big challenge is to achieve the magnetic field identity of the two kickers within an accuracy of 0.1%. This presentation overviews the proposed injection system and reports the development status focusing on the solid-state pulse generator.
	Slides WEYGBF4 [3.062 MB]
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WEPAF055	Time-Synchronized Beam Diagnostics at SPEAR3	diagnostics, feedback, timing, injection	1948
	Q. Lin, Z.H. Sun Donghua University, Shanghai, People's Republic of China P. Boussina, W.J. Corbett, D.J. Martin, J.A. Safranek, K. Tian SLAC, Menlo Park, California, USA D. Teytelman Dimtel, San Jose, USA
	The SPEAR3 timing system supplies a 10Hz trigger pulse synchronous with charge injection into the main storage ring. In the past the 10Hz pulse train has been used to study injected charge transients as seen by visible-light synchrotron radiation diagnostics and turn-by-turn BPMs. More recently the 10Hz pulse has been used to synchronize the bunch-by-bunch feedback data acquisition system with other triggered diagnostic systems. The suite of measurement systems can be used to study injected beam dynamics, grow/damp instability transients and drive/damp physics.
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WEPAF056	A Graphical User Interface for Transverse Bunch-by-Bunch Feedback at SPEAR3	feedback, interface, impedance, software	1951
	K. Tian, W.J. Corbett, D.J. Martin, J.J. Sebek SLAC, Menlo Park, California, USA Q. Lin Donghua University, Shanghai, People's Republic of China D. Teytelman Dimtel, San Jose, USA
	Recently a transverse bunch-by-bunch feedback kicker was installed in SPEAR3 to control beam instabilities, remove unwanted satellite bunches and test resonant bunch excitation schemes for short pulse x-ray production. In conjunction with DIMTEL processing electronics, the feedback system can successfully stabilize undesirable beam modes and opens up the potential for more advanced investigations of bunch-by-bunch beam dynamics. To streamline the process, a graphical user interface was developed that allows the user to 'script' beam physics measurements from a single panel. At the press of a button the panel automatically downloads the measurement parameters, acquires the raw data and provides graphical displays of the beam response with calculated metadata. In this paper we present the interface format and examples of automated measurements.
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WEPAF072	Transverse Feedback System for the CERN FCC-hh Collider	injection, feedback, damping, emittance	1997
	W. Höfle, J. Komppula, G. Kotzian, K.S.B. Li, D. Valuch CERN, Geneva, Switzerland
	For the future hadron Collider (FCC-hh) being studied at CERN a strong transverse feedback system is required to damp coupled bunch instabilities. This system is also planned to be used for injection damping. Based on the LHC transverse feedback design we derive requirements for power and kick strength for this system for the different options of bunch spacing, 25 ns and 5 ns, and injection energy. Operation at high gain and close to a half integer tune is being considered and constrains the layout and signal processing. Requirements for the pick-up resolution are derived from the need to keep the emittance increase small. The performance is evaluated using numerical simulations based on the headtail code. Future areas of research and development and possible prototype developments are outlined.
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WEPAK010	Simulations and Measurements of the BPM Non Linearity and Kicker Timing Influence on the Tune Shift With Amplitude (TSWA) Measurement at BESSY II	simulation, optics, factory, diagnostics	2107
	F. Kramer, P. Goslawski, J.G. Hwang, A. Jankowiak, P. Kuske, M. Ruprecht, A. Schälicke HZB, Berlin, Germany
	The Tune Shift With Amplitude (TSWA) does not only determine the position of the stable fix points for the Transverse Resonant Island Buckets (TRIBs) but also represents a global observable for the nonlinear optics in general. For theoretical investigations of the TRIBs a reliable nonlinear optics of the machine is required and thus all measurable global observables for the nonlinear optics are of great interest. The measurement of the TSWA for the BESSY II standard optics was performed using an injection kicker to excite high amplitude betatron oscillations and then extract the amplitude dependant frequency from the synchrotron radiation damped oscillation with a Hilbert transformation. With TRIBs optics the injection kicker was not able to sufficienty excite the beam. The impact and correctability of the BPM nonlinearity at the reached amplitudes and the reason for the failure of the excitation method for our TRIBs optics shall be looked onto in this paper.
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WEPAL025	Development of a Low-Latency, High-Precision, Beam-Based Feedback System Based on Cavity BPMs at the KEK ATF2	feedback, cavity, dipole, extraction	2212
	R.L. Ramjiawan, D.R. Bett, N. Blaskovic Kraljevic, R.M. Bodenstein, T. Bromwich, P. Burrows, G.B. Christian, C. Perry JAI, Oxford, United Kingdom
	A low-latency, intra-train feedback system employing cavity beam position monitors (BPMs) has been developed and tested at the Accelerator Test Facility (ATF2) at KEK. The feedback system can be operated with either position information from a single BPM to provide local beam stabilisation, or by using position information from two BPMs to stabilise the beam at an intermediate location. The correction is implemented using a stripline kicker and a custom power amplifier, with the feedback calculations being performed on a digital board built around a Field Programmable Gate Array (FPGA). The addition of indium sealing to the BPMs to increase the cavities' Q-values has led to improvements to the BPM system resolution, with current measurements of the resolution of order 20 nm. The feedback performance was tested with beam trains of two bunches, separated by 280 ns and with a charge of ~1 nC. For single- (two-)BPM feedback, stabilisation of the beam has been demonstrated to below 50 nm (41 nm). Ongoing work to improve the feedback performance further will be discussed.
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WEPAL036	Implementation of CSNS RCS Beam Injection and Extraction Modes in Timing System	extraction, injection, timing, linac	2247
	P. Zhu, M.Y. Huang, D.P. Jin, G. Lei, G.L. Xu, Y.L. Zhang IHEP, Beijing, People's Republic of China L. Wang CSNS, Guangdong Province, People's Republic of China
	Funding: Institute of High Energy Physics， Chinese Academy of Sciences, Beijing 100049, China; Dong guan Neutron Science Center, Dong guan 523803, China Based on the physical design of the accelerator and the demand of the beam research, we designed four RCS beam injection modes and two RCS beam extraction modes, each of which corresponds to a series of specific timing for the accelerator. RCS beam injection and extraction modes are implemented on "VME + customized boards" hardware platform. In this paper, we will introduce the design and implementation of RCS beam injection and extraction modes as well as the RCS timing requirements and implementation in detail.
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WEPAL055	TPS Beam Trip Analysis and Dose Distribution	radiation, SRF, neutron, storage-ring	2302
	B.Y. Chen, F.Y. Chang, S. Fann, C.S. Huang, C.H. Kuo, T.Y. Lee, C.C. Liang, W.Y. Lin, Y.C. Lin, Y.-C. Liu NSRRC, Hsinchu, Taiwan
	Failure analysis during TPS users operation is im-portant to improve the performance of the TPS storage ring. In this report, we discuss the particular radiation dose patterns, relevant to different beam trips, and the development of a tool to help us analyse this dose distri-bution. We will use this analysing tool to train our ability for future failure analysis to shorten the time it takes to find the problem.
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WEPAL057	Methods to Detect Error Sources and Their Application at the TPS	photon, storage-ring, cavity, injection	2305
	C.H. Huang, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, K.H. Hu, C.Y. Wu NSRRC, Hsinchu, Taiwan
	For a low-emittance photon light source, beam stability is a very important property to attain a high-quality photon beam. While it is hard to avoid beam perturbations in a storage ring, it is more important to quickly find the source locations and to remove or eliminate the sources as soon as possible. In this report, we develop a method to identify the locations of multiple sources. For a source with a particular frequency, the relative phase between sources can also be obtained. This method has been a useful tool during TPS operation and its methodology and practical applications are described in this report.
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WEPAL063	A Method to Tune Pulse Magnets' Waveforms	injection, power-supply, GUI, septum	2320
	T.Y. Lee, B.Y. Chen, S. Fann, C.S. Huang, C.H. Kuo, C.C. Liang, W.Y. Lin, Y.-C. Liu, Y.C. Yang NSRRC, Hsinchu, Taiwan
	Pulse magnets are used in storage ring injection kickers. The waveform of the the four kickers have strong relation with injection efficiency. A slightly offset of waveform may cause the four kickers mismatched, which would lead to storaged beam loss and decrease injection efficiency. In order to define the peak value and timing of the half-sine waveform which has noises interfering diagnosis, a curve-fitting method was introduced to monitor and fine-tuning the waveform. The waveforms' data are also archived for reference in case of replacing power supplies. By using this method, it helps to retain a consistent injection efficiency after the power supplies maintenance or replacement.
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WEPAL066	Determination of RF Resonator Axis Inclination to Beam Axis in Electron-Positron Storage Ring	experiment, resonance, electron, positron	2330
	Leshenok D. Leshenok NSU, Novosibirsk, Russia S.A. Nikitin BINP SB RAS, Novosibirsk, Russia
	We proposed and tested the method that allows obtaining of an upper limit for an angle of the RF resonator axis inclination relative to a beam axis. Such disturbance gives an additional contribution to separation of electron and positron orbits due to action of the transverse component of the electric field. In the horizontal plane, this effect can lead to increase of the difference between electrons and positrons spin precession frequencies in a storage mono-ring collider. This effect can play a great role in FCC. At the angular disturbance of axis in the certain VEPP-4M RF resonators ~10^-3 rad, the difference between the spin frequencies is about 10^-8. Our method is based on resonant excitation of betatron oscillations using phase modulation of the master oscillator of the RF system. The maximal amplitude of the enforced oscillations is measured by the counting rate of the VEPP-4M Touschek polarimeter scintillation counters. Comparison of the obtained results with the data of the special calibration experiment allows estimating the value of the inclination angle. In this calibrated experiment the betatron oscillations excite using the VEPP-4M kicker.
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WEPAL079	Control of Intra-Bunch Vertical Motion in the SPS with GHz Bandwidth Feedback	feedback, controls, damping, injection	2365
	J.D. Fox, J.E. Dusatko, C.H. Rivetta, O. Turgut SLAC, Menlo Park, California, USA H. Bartosik, E.R. Bjørsvik, W. Höfle, G. Kotzian, K.S.B. Li, E. Métral, B. Salvant, U. Wehrle CERN, Geneva, Switzerland S. De Santis LBNL, Berkeley, California, USA
	Funding: Work supported by the U.S. Department of Energy DE-AC02-76SF00515, US LHC Accelerator Research program, CERN LHC Injector Upgrade Project and the US-Japan Cooperative Program in High Energy Physics. A GHz bandwidth vertical beam feedback system has been in development at the CERN SPS to explore control of unstable beam motion in single bunch and bunch train configurations. We present measurements and recent studies of stable and unstable motion for intensities up to 2x10¹¹ p/bunch. The system has been operated at 3.2GS/s with 16 samples across a 5 ns RF bucket (4.2 ns 3 σ bunch at injection). Experimental results confirm damping of intra-bunch instabilities in Q20, Q22 and Q26 optics configurations. Instabilities with growth times of 200 turns are well-controlled from injection, consistent with the achievable gains for the 2 installed stripline kickers with 1 kW broadband total power. Studies of the damping achieved with the diagonal FIR controllers and existing system noise floors are highlighted to evaluate benefits of MIMO feedback controllers. The work is motivated by anticipated intensity increases from the LIU and HL-LHC upgrade programs, and has included the development of a new 1 GHz bandwidth slotline kicker structure and associated amplifier system
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WEPMF020	Pulsed Systems for eRHIC Beam Injection and Extraction	injection, extraction, storage-ring, electron	2410
	W. Zhang, M. Blaskiewicz, A. Hershcovitch, C.J. Liaw, H. Lovelace III, M. Mapes, G.T. McIntyre, J.-L. Mi, C. Montag, C. Pai, V. Ptitsyn, J. Sandberg, N. Tsoupas, J.E. Tuozzolo, G.M. Wang, W.-T. Weng, F.J. Willeke, H. Witte, Q. Wu BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The electron-ion collider eRHIC requires a variety of kickers and septa for injection and extraction of beams throughout the entire collider complex. We plan to use pulsed systems for beam injection and extraction in Electron RCS, Electron Storage Ring, and Hadron ring. In this paper, we describe the pulsed systems required for beam transfer in the eRHIC Ring-Ring Pre-conceptual Design. We will outline the parameter ranges, technology choices, and opportunities for research and development in pulsed power technology.
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WEPMF075	Performance Measurements and Analysis of Jitter Like Events for the PS Injection Kicker System	controls, operation, injection, simulation	2549
	A. Ferrero Colomo, J.C.C.M. Borburgh, L. Ducimetière, L.M.C. Feliciano, V. Forte, M.A. Fraser, T. Kramer, L. Sermeus CERN, Geneva, Switzerland
	In the framework of the LIU project, several modifications have been made to the CERN PS injection kicker system during the winter stop 2016-2017 (EYETS). Current waveform and beam-based measurements were carried out in 2017 to validate the implemented design changes by observing the magnetic field impact on the beam. During these long-term measurements, increased values for the rise and fall times were observed when compared to single shot observations of the current waveform. An unknown source of jitter-like pre-firing in the main switch has been identified, creating an additional challenge to meet the already tight system rise and fall time specifications. This paper briefly describes the efforts made to fine tune the pulse generator after the EYETS, summarises the optimised configuration and analyses the observed jitter events. A new triggering system design is briefly outlined to address the issue.
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WEPMF076	First Prototype Inductive Adder for the FCC Injection	injection, distributed, impedance, high-voltage	2553
	D. Woog, M.J. Barnes, A. Ferrero Colomo, J. Holma, T. Kramer CERN, Geneva, Switzerland
	A highly reliable kicker system is required as part of the injection for the FCC. A significant weak point of conventional kicker systems is often the pulse generator, where a Pulse Forming Network/Line (PFN/PFL) is discharged through a thyratron switch to generate the current pulse for the kicker magnet. This design has several disadvantages: in particular the occasional erratic turn-on of the switch which cannot be accepted for the FCC. A potential replacement is the inductive adder (IA) that uses semiconductor switches and distributed capacitors as energy storage. The modular design, low maintenance and high flexibility make the IA a very interesting alternative. In addition, the ability to both turn-on and off the current also permits the replacement of PFN/PFL by the capacitors. A first FCC prototype IA, capable of generating 9 kV and 2.4 kA pulses, has been designed and built at CERN. It will be upgrade to a full-scale prototype (15 kV, 2.4 kA) in 2018. This paper presents measurement results from the 9 kV prototype and outlines the conceptual changes and expected performance of the 15 kV prototype.
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WEPMF077	Demonstration of Feasibility of the CLIC Damping Ring Extraction Kicker Modulators	flattop, extraction, damping, collider	2557
	J. Holma, M.J. Barnes, A. Ferrero Colomo CERN, Geneva, Switzerland
	The CLIC study is investigating the technical feasibility of an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. Pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. The DR kicker systems must provide extremely stable field pulses to avoid beam emittance increase. The DR extraction kicker system consists of a stripline kicker and two pulse modulators. Specifications for the electromagnetic field pulses require that the modulator produce pulses of 160 or 900 ns flattop duration, ±12.5 kV and 305 A, with ripple and droop of not more than ±0.02 % (±2.5 V) with respect to an ideal waveform. Inductive adder topology has been chosen for the pulse modulators where the output waveform can be adjusted by applying analogue modulation methods. Two full-scale, 20-layer, 12.5 kV prototype inductive adders have been designed and built, and they are being tested at CERN. These modulators will be tested with a prototype stripline kicker, installed in a beamline at ALBA Synchrotron Light Source in Spain. The results of the laboratory tests and measurements are presented.
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WEPMF086	Eradication of Mercury Ignitron from the 400 kA Magnetic Horn Pulse Generator for CERN Antiproton Decelerator	proton, antiproton, target, operation	2586
	V. Namora, M. Calviani, L. Ducimetière, P. Faure, L.E. Fernandez, G. Gräwer, V. Senaj CERN, Geneva, Switzerland
	The CERN Antiproton Decelerator (AD) produces low-energy antiprotons for studies of antimatter. A 26 GeV proton beam impacts the AD production target which produces secondary particles including antiprotons. A magnetic Horn (AD-Horn) in the AD target area is used to focus the diverging antiproton beam and increase the antiproton yield enormously. The horn is pulsed with a current of 400 kA, generated by capacitor discharge type generators equipped with ignitrons. These mercury-filled devices present a serious danger of environmental pollution in case of accident and safety constraints. An alternative has been developed using solid-state switches and diodes. Similar technology was already implemented at CERN for ignitron eradication in the SPS Horizontal beam dump in the early 2000s. A project was launched to design and set up a full-scale test-bench, to install and test a dedicated solid-state solution. Following the positive results obtained from the test-bench, the replacement of ignitrons by solid-state devices in the operational AD-Horn facility is currently under preparation. This paper describes the test-bench design and results obtained for this very high current pulser.
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WEPMF089	Measurements of Electromagnetic Properties of Ferrites as a Function of Frequency and Temperature	impedance, injection, coupling, simulation	2592
	A. Chmielinska, M.J. Barnes, F. Caspers, B.K. Popovic, C. Vollinger CERN, Geneva, Switzerland
	Fast kicker magnets are used to inject beam into and extract beam out of the CERN accelerator rings. These kickers are often ferrite loaded transmission line type magnets with a rectangular shaped aperture through which the beam passes. The interaction of the beam with the resistive part of the longitudinal beam coupling impedance leads to power dissipation and heating of different elements in the accelerator ring. In particular, power deposition in the kicker magnets can be a limitation: if the temperature of the ferrite yoke exceeds the Curie temperature, the beam will not be properly deflected. In addition, the imaginary portion of the beam coupling impedance contributes to beam instabilities. A good knowledge of electromagnetic properties of materials up to GHz frequency range is essential for a correct impedance evaluation. This paper presents the results of transmission line measurements of complex initial permeability and permittivity for different ferrite types. We present an approach for deriving electromagnetic properties as a function of both frequency and temperature; this information is required for simulating ferrite behaviour under realistic operating conditions.
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WEPMG004	Design of the Future High Energy Beam Dump for the CERN SPS	operation, shielding, dumping, simulation	2612
	S. Pianese, J.A. Briz Monago, M. Calviani, D. Grenier, P.B. Heckmann, J. Humbert, R. Illan Fiastre, A. Perillo-Marcone, G. Romagnoli, S. Sgobba, D. Steyart, V. Vlachoudis CERN, Geneva, Switzerland
	The future CERN Super Proton Synchrotron (SPS) internal dump (Target Internal Dump Vertical Graphite, known as TIDVG#5), to be installed during CERN's Long Shutdown 2 (2019-2020), will be required to intercept beam dumps from 26 to 450 GeV, with increased intensity and repetition rates with respect to its predecessor (TIDVG#4). The beam power to be managed by the dump will increase by approximately a factor of four; resulting in new challenges in terms of design in order to fulfil the highly demanding specification, which is based on guaranteeing a good performance of the machine with little or no limitations imposed by this device. This paper presents the proposed design, including material selection, manufacturing techniques and thermo-mechanical simulations under different operational scenarios expected during the lifetime of the device.
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WEPMK001	Preliminary Design of a Cooling System for the LHC Injection Kicker Magnets	injection, vacuum, operation, impedance	2624
	L. Vega Cid, M.J. Barnes, L. Ducimetière, M.T. Moester, V. Vlachodimitropoulos, W.J.M. Weterings CERN, Geneva, Switzerland A. Abánades ETSII UPM, Madrid, Spain
	The CERN Large Hadron Collider (LHC) is equipped with two fast pulsed magnet systems (MKIs) that inject particle beams from the injector chain. Future operation for High Luminosity LHC (HL-LHC) with high intensity beams will cause heating of the ferrite yokes of the MKIs beyond their Curie temperature, preventing injection until the yokes cool down. Beam coupling impedance studies show that it is possible to move a substantial portion of the beam induced power deposition from the upstream ferrite yokes, which are the yokes with the highest power deposition, to ferrite rings located at the upstream end of the magnet. Thermal predictions show that this power redistribution, combined with the installation of a cooling system around the rings, will maintain the temperatures of all the yokes and ferrite rings below their Curie point. Since the rings are not pulsed to high voltage, whereas the ferrite yokes are, the installation of a cooling system is feasible around the rings. The proposed design of the cooling system will be tested to ensure good performance before its installation on the MKIs. The details of the simulations and the design process are reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMK001
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WEPMK002	Longitudinal Impedance Analysis of an Upgraded LHC Injection Kicker Magnet	impedance, simulation, injection, vacuum	2628
	V. Vlachodimitropoulos, M.J. Barnes, L. Vega Cid, W.J.M. Weterings CERN, Geneva, Switzerland
	Prior to Long Shutdown 1 (LS1) one of the LHC injection kickers (MKIs) occasionally exhibited high temperatures leading to significant turnaround times. After a successful impedance mitigation campaign during LS1, the MKI ferrite yokes have remained below their Curie point and have not limited LHC's availability. However, for HL-LHC operation the MKI yokes are expected to exceed their Curie temperatures after long physics runs. To ensure uninterrupted future HL-LHC operation, a modified beam screen design, relocating some of the heat load to more easily cooled parts, and a suitable cooling system are under development as the current baseline for the HL-LHC upgrade of the MKIs. An upgraded beam screen providing such relocation has been designed, simulated and compared to the existing model. To validate simulations, two longitudinal beam coupling impedance measurement techniques have been used and the results are compared to predictions. The modified beam screen was implemented in an upgraded MKI installed in the LHC during the Year End Technical Stop (YETS) 2017/18.
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WEPMK003	An Upgraded LHC Injection Kicker Magnet	injection, vacuum, electron, impedance	2632
	M.J. Barnes, C. Bracco, G. Bregliozzi, A. Chmielinska, L. Ducimetière, B. Goddard, T. Kramer, H. Neupert, L. Vega Cid, V. Vlachodimitropoulos, W.J.M. Weterings, C. Yin Vallgren CERN, Geneva, Switzerland A. Chmielinska EPFL, Lausanne, Switzerland
	Funding: Work supported by the HL-LHC project. An upgrade of the LHC injection kickers is necessary for HL-LHC to avoid excessive beam induced heating of these magnets: the intensity of the HL-LHC beam will be twice that of LHC. In addition, in the event that it is necessary to exchange an injection kicker magnet, the newly installed kicker magnet would limit HL-LHC operation for a few hundred hours due to dynamic vacuum activity. Extensive studies have been carried out to identify practical solutions to these problems: these include redistributing a significant portion of the beam induced power deposition to ferrite parts of the kicker magnet which are not at pulsed high voltage and water cooling of these parts. Furthermore a surface coating, to mitigate dynamic vacuum activity, has been selected. The results of these studies, except for water cooling, have been implemented on an upgraded LHC injection kicker magnet: this magnet was installed in the LHC during the 2017-18 Year End Technical Stop. This paper presents the upgrades, including some test and measurement results.
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WEPMK005	Preliminary Results from Validation Measurements of the Longitudinal Power Deposition Model for the LHC Injection Kicker Magnet	impedance, injection, coupling, operation	2636
	V. Vlachodimitropoulos, M.J. Barnes, A. Chmielinska CERN, Geneva, Switzerland A. Chmielinska EPFL, Lausanne, Switzerland
	During Run 1 of the LHC, one of the injection kicker magnets (MKIs) exhibited an excessively high ferrite temperature, caused by coupling of the high intensity beam to the real impedance of the magnet. Beam-screen upgrades, implemented during Long Shutdown 1 (LS1), have been very effective in reducing beam coupling impedance and since then the MKIs have not limited LHC's availability. However, temperature measurements during operation have shown that one end of the MKI's ferrite yoke is consistently hotter than the other. Detailed simulation models and data post-processing algorithms have been developed to understand and mitigate the observed behaviour. In the present paper, the model used to obtain the power loss distribution along the magnet is presented. The model is subsequently applied to two MKI design configurations under study: (i) the one currently in operation and (ii) an upgraded magnet that was installed in the LHC tunnel during the Year End Technical Stop (YETS) 2017/18. In order to validate the expected behaviour a novel measurement technique was developed, applied in both configurations and compared to predictions. The results obtained are reported and conclusions regarding the effectiveness of the design are drawn.
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WEPML021	First Performance Results of the PIP2IT MEBT 200 Ω Kicker Prototype	booster, impedance, ISOL, target	2724
	G.W. Saewert, M.H. Awida, B.E. Chase, A.Z. Chen, J. Einstein-Curtis, D. Frolov, K.S. Martin, H. Pfeffer, D. Wolff Fermilab, Batavia, Illinois, USA S. Khole BARC, Trombay, Mumbai, India D. Sharma RRCAT, Indore (M.P.), 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 PIP-II project is a program to upgrade the Fermilab accelerator complex. The PIP-II linac includes a 2.1 MeV Medium Energy Beam Transport (MEBT) section that incorporates a unique chopping system to perform arbi-trary, bunch-by-bunch removal of 162.5 MHz structured beam. The MEBT chopping system will consist of two identical kickers working together and a beam absorber. One design of two having been proposed has been a 200 Ω characteristic impedance traveling wave dual-helix kicker driven with custom designed high-speed switches. This paper reports on the first performance results of one prototype kicker built, installed and tested with beam at the PIP-II Injector Test (PIP2IT) facility. The helix deflector design details are discussed. The electrical performance of the high-speed switch driver operating at 500 V bias is presented. Tests performed were chopping beam at 81.25 MHz for microseconds as well as with a truly arbitrary pattern for 550 us bursts having a 45 MHz average switching rate and repeating at 20 Hz.
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WEPML029	Vacuum System of the HESR at FAIR, Status of Tests, Layout and Manufacturing	vacuum, dipole, injection, controls	2748
	F.M. Esser, N.B. Bongers, J. Böker, P. Chaumet, R. Gebel, R. Greven, S. Hamzic, H. Jagdfeld, F. Klehr, B. Laatsch, G. Langenberg, D. Marschall, A. Mauel, G. Natour, D. Prasuhn, L. Reifferscheidt, M. Schmitt, L. Semke, R. Tölle FZJ, Jülich, Germany
	The Research Center Jülich is leading a consortium being responsible for the design and manufacturing of the High-Energy Storage Ring (HESR) which is part of the FAIR project in Darmstadt, Germany. The HESR is designed for antiprotons within a momentum range of 1.5-15 GeV/c but can also be used for heavy ion experiments. Therefore the vacuum quality is expected to be 10^-11 mbar or better which is a great challenge on the overall vacuum layout as well as on the surface quality of the chambers and beam tubes. Whereas all bent dipole chambers are installed, the manufacturing of the pumping bodies with integrated RF meshes as well as several diagnostic chambers are in the focus of investigation. To validate the intended pumping concept of both the bake-out arc sections and the non-bakable straight sections, final tests at the operational test benches are planned. In parallel, the purchasing of valves and first pumps will be prepared. The actual layout of the HESR vacuum system and its components will be presented as well as the progress of manufacturing of several vacuum chambers. The latest experimental test results will be presented also.
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WEPML069	Fast Kicker and Pulser R&D for the HEPS on-Axis Injection System	injection, impedance, vacuum, simulation	2846
	H. Shi, J. Chen, Z. Duan, L. Huo, P. Liu, X.L. Shi, G. Wang, L. Wang, N. Wang IHEP, Beijing, People's Republic of China
	The HEPS plans to adopt on-axis injection scheme because the dynamic aperture of machine is not large enough for off-axis injection for its baseline 7BA lattice design. A sets of super fast kicker and pulser of ±15kV amplitude, 15ns pulse bottom width are needed for bunch spacing of 10ns to minimize perturbation on adjacent bunches. To achieve these requirement, a multifaceted R&D program including the strip-line kicker and HV pulser, was initiated last 2 years. So far, the prototype development of a 750mm long strip-line kicker and a DSRD pulser was completed and the preliminary test results show they can meet the baseline requirement of the HEPS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML069
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THXGBD4	Sirius Light Source Status Report	storage-ring, injection, booster, MMI	2886
	A.R.D. Rodrigues, F.C. Arroyo, O.R. Bagnato, J.F. Citadini, R.H.A. Farias, J.G.R.S. Franco, R. Junqueira Leao, L. Liu, S.R. Marques, R.T. Neuenschwander, C. Rodrigues, F. Rodrigues, R.M. Seraphim, O.H.V. Silva LNLS, Campinas, Brazil
	Sirius is a Synchrotron Light Source Facility based on a 4th generation 3 GeV low emittance electron storage ring that is under construction in Campinas, Brazil. Presently the main tunnel for the accelerators is ready to start installations. The Linac tunnel was delivered earlier and the 150 MeV Linac from SINAP is almost ready to start commissioning early May. Commissioning of the storage ring is expected to start by the end of this year (2018). In this paper we briefly review the overall project parameters and design concepts and focus on highlights from the main subsystems.
	Slides THXGBD4 [28.400 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THXGBD4
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THYGBF2	PIP-II Injector Test Warm Front End: Commissioning Update	rfq, operation, emittance, focusing	2943
	L.R. Prost, R. Andrews, C.M. Baffes, J.-P. Carneiro, B.E. Chase, A.Z. Chen, E. Cullerton, P. Derwent, J.P. Edelen, J. Einstein-Curtis, D. Frolov, B.M. Hanna, D.W. Peterson, G.W. Saewert, A. Saini, V.E. Scarpine, A.V. Shemyakin, V.L. Sista, J. Steimel, D. Sun, A. Warner 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 Warm Front End (WFE) of the Proton Improvement Plan II Injector Test [1] at Fermilab has been constructed to its full length. It includes a 15-mA DC, 30-keV H⁻ ion source, a 2 m-long Low Energy Beam Transport (LEBT) with a switching dipole magnet, a 2.1 MeV CW RFQ, followed by a Medium Energy Beam Transport (MEBT) with various diagnostics and a dump. This report presents the commissioning status, focusing on beam measurements in the MEBT. In particular, a beam with the parameters required for injection into the Booster (5 mA, 0.55 ms macro-pulse at 20 Hz) was transported through the WFE.
	Slides THYGBF2 [2.434 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THYGBF2
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THPAF006	Simulations of Cooling Rate and Diffusion for Coherent Electron Cooling Experiment	electron, FEL, simulation, bunching	2957
	J. Ma, V. Litvinenko, G. Wang BNL, Upton, Long Island, New York, USA V. Litvinenko Stony Brook University, Stony Brook, USA
	Start-to-end numerical simulations have been performed using the code SPACE and GENESIS for the single pass of gold ions through the coherent electron cooling (CeC) device installed in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Cooling rate of CeC experiment has been predicted using off-reference energy ions in a finite Gaussian electron beam through a realistic beam-line, in which settings of quadrupoles and free-electron laser (FEL) device are relevant to BNL RHIC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF006
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THPAF084	Impact of RF Coupler Kicks on Beam Dynamics in BESSY VSR	cavity, simulation, SRF, lattice	3182
	T. Mertens Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Berlin, Germany T. Atkinson, F. Glöckner, A. Jankowiak, M. Ries, A.V. Tsakanian HZB, Berlin, Germany
	The expected BESSY II upgrade to BESSY VSR requires the installation of a superconducting RF system, consisting of four cavities. Two cavities will operate at 1.5 GHz and two at 1.75 GHz. Each of them is equipped with a Fundamental Power Coupler and with Higher Order Mode (HOM) damping waveguide couplers. Dedicated simulations of these cavities and couplers have shown that at the location of the FPC the beam will see a transverse kick [], perturbing the closed orbit and affecting transverse beam dynamics. We present the results of simulations and experiments of the impact on transverse beam dynamics of these coupler induced kicks for different FPC orientations. [] Study on RF Coupler Kicks of SRF Cavities in the BESSY VSR Module A. Tsakanian#, H.-W. Glock, T. Mertens, M. Ries, A. Velez, J. Knobloch IPAC18
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THPAK002	Updated Model of the Resistive Wall Impedance for the Main Ring of J-PARC	impedance, space-charge, hadron, injection	3204
	B. Yee-Rendón, Y.H. Chin, H. Kuboki, T. Toyama KEK, Ibaraki, Japan M. Schenk CERN, Geneva, Switzerland
	The resistive wall impedance is one of the major contributors of the impedance in the Main Ring of J-PARC. The present model assumes round chambers of stainless steel with perfect magnet boundary conditions for its surroundings. This work presents the model of the resistive wall impedances taking into account the different chamber geometries of Main Ring, the materials and more realistic surroundings. The models were benchmarked with measurements of the coherent tune shift of the Main Ring of J-PARC. The simulation of beam instabilities is a helpful tool to evaluate potential threats against the machine protection of the high intensity beams.
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THPAK015	Impedance and Heat Load Analysis of the Stripline Kicker in HEPS	impedance, simulation, coupling, injection	3234
	N. Wang, J. Chen, Z. Duan, H. Shi, S.K. Tian, L. Wang, H.S. Xu IHEP, Beijing, People's Republic of China
	In the High Energy Photon Source (HEPS), strip-line kickers are adopted for beam injection and extraction. Beam coupling impedance contribution from the strip-line kicker is calculated. Detailed studies on the heat load dissipation have been performed. The peak electric field on the blade and the induced voltage on the feedthroughs due to the beam passage are also calculated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK015
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THPAK043	Performance Optimization of a Beam Dynamics PIC Code On Hybrid Computer Architectures	GPU, simulation, plasma, HOM	3309
	Zh.C. Liu IHEP, Beijing, People's Republic of China J. Qiang LBNL, Berkeley, California, USA
	The self-consistent multi-particle tracking based on particle-in-cell method (PIC) has been widely used in particle accelerator beam dynamics study. However, the PIC simulation is time-consuming and needs to use modern parallel computers for high resolution applications. In this paper, we implemented and optimized a parallel beam dynamics PIC code on two types of hybrid parallel computer architectures: one is the GPU and GPU cluster, while the other is the "Knight Landing" CPU cluster.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK043
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THPAK055	Suppression of Transverse Beam Instabilities by Stripline Kickers at TPS	impedance, feedback, damping, storage-ring	3346
	P.J. Chou, C.K. Chan, C.-C. Chang, K.T. Hsu, K.H. Hu, C.K. Kuan, I.C. Sheng, F.H. Tseng NSRRC, Hsinchu, Taiwan
	Collective beam instabilities could limit the accelerator performance if proper countermeasures are not in place. Active beam feedback systems are commonly used to suppress beam instabilities. The resistive wall impedance including phase-II insertion devices at TPS are calculated with analytical formulas. The growth rate of transverse coupled bunch instabilities due to wall impedance is estimated by theory. The RF properties of existing stripline kickers in TPS are analyzed with a 3-D electromagnetic simulation code GdfidL. Based on the above analysis, the requirements for a beam feedback system are calculated and the results are reported.
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THPAK057	Simulations of Optical Stochastic Cooling with ELEGANT	damping, undulator, pick-up, radiation	3354
	M.B. Andorf, P. Piot Northern Illinois University, DeKalb, Illinois, USA V.A. Lebedev, V.A. Lebedev, P. Piot Fermilab, Batavia, Illinois, USA
	Fermilab is pursuing a proof-of-principle test of the Optical Stochastic Cooling (OSC) of 100 MeV electrons in the Integrable Optics Test Accelerator. In support of this we present simulations of horizontal damping with OSC. We find excellent agreement with theory on the amplitude dependent damping rates. Additionally particle tracking is used to confirm the necessity and effectiveness of sextupoles used to correct non-linear path lengthening in the OSC chicane.
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THPAK067	Progress Toward a Self-Consistent Beam at the Spallation Neutron Source	injection, solenoid, simulation, quadrupole	3382
	J.A. Holmes, S.M. Cousineau, T.V. Gorlov, M.A. Plum ORNL, Oak Ridge, Tennessee, USA N.J. Evans ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the US DOE. This research was supported by the DOE Office of Science, Accelerator and Detector Research Program. We have proposed to inject a self-consistent "rotating" beam into the Spallation Neutron Source (SNS). Self-consistent beam distributions are defined to be ellipsoidal, or elliptical in 2D, distributions that have uniform density and that retain these properties under all linear transformations. We have made much progress since the original proposal. We have demonstrated computationally the feasibility of injecting a rotating beam under realistic physics assumptions. We have optimized the injection scheme with respect to beam loss and to minimum necessary hardware changes. We have also determined how existing SNS beam diagnostic equipment can be used to verify the self-consistency of the injected beam. This paper will report the details of this work as well as the status of plans to carry out the self-consistency experiments.
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THPAL028	Commissioning of the Bunch-by-Bunch Feedback System in the MAX IV 1.5 GeV Ring	feedback, cavity, storage-ring, synchrotron	3688
	D. Olsson, Å. Andersson, F.J. Cullinan, P.F. Tavares MAX IV Laboratory, Lund University, Lund, Sweden
	The MAX IV 1.5 GeV ring is an electron storage ring for production of synchrotron light in the IR to soft X-ray spectral range. The ring will deliver light to its first users during 2018. Bunch-By-Bunch (BBB) feedback has been needed to suppress coupled-bunch mode instabilities (CBMIs), and the feedback has this far been provided in all three planes by a single stripline kicker. This is done by combining the horizontal and vertical baseband feedback signals with the longitudinal feedback signal that is upconverted to the 150 MHz - 250 MHz range. The combined signal is then fed to two stripline electrodes. The layout of the BBB feedback system in the MAX IV 1.5 GeV ring is presented in this paper. Results from instability studies are also discussed.
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THPAL082	Development of a New Modular Switch Using a Next-Generation Semiconductor	power-supply, pulsed-power, ISOL, timing	3841
	T. Takayanagi, K. Horino, T. Ueno JAEA/J-PARC, Tokai-mura, Japan
	An ultra-high-speed short pulse switch for high power have been developed by using SIC - MOSFET which is one of next generation semiconductors. Semiconductor switches using SIC-MOSFETs are expected to replace the thyratron, and they are composed of circuits in which many semiconductor switches are multiplexed in series and parallel for high power. Semiconductor switches using SIC-MOSFETs are expected to replace the thyratron, and they are also designed by connecting many semiconductor switches in parallel-series. To realize a low switching noise, it is common to form a symmetrical circuit. However, as the number of parallel connections increases, the circuit length between input and output becomes longer, so the output waveform is distorted due to any timing jitter or level fluctuation. Therefore, we propose a radially symmetric type of a module switch which does not cause level fluctuation due to the timing jitter by equalizing the circuit length independently of the number of semiconductor switches. The design and preliminary test results of two types of switch circuits, radially symmetric type and line symmetric type are presented here.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL082
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THPAL128	Autonomous Topography Detection and Traversal for an Inspection Robot Within the Beamline of Particle Accelerators	vacuum, experiment, FEL, heavy-ion	3943
	N. Schweizer Technische Universität Darmstadt (TU Darmstadt, RMR), Darmstadt, Germany I. Pongrac GSI, Darmstadt, Germany
	Particle accelerators feature ultra-high vacuum pipe systems with unique topography, i.e. with a multitude of different vacuum chambers of varying dimensions and varying pipe apertures. In order to be able to examine the interior of the entire vacuum system, even those parts which are not accessible without disassembling large parts of the accelerator, a semi-autonomous robot is being developed which shall traverse and visually inspect the vacuum system of particle accelerators. We present a generic concept based on distance sensors for the inspection robot to detect steps between vacuum chambers and gaps in the beamline. Movement strategies to autonomously overcome these basic obstacles are introduced. For evaluation we use simulations of ideal environments with flat surfaces as well as realistic beam pipe environments of the SIS100 particle accelerator. Additionally, a prototype of our robot concept confirms the implementation of all maneuvers. Results show that obstacles of previously unknown dimensions can be detected and reliably traversed.
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THPMF002	Studies for Injection with a Pulsed Multipole Kicker at ALBA	injection, storage-ring, lattice, octupole	4030
	G. Benedetti, U. Iriso, M. Pont, D. Ramos Santesmases ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain E. Ahmadi ILSF, Tehran, Iran
	Injection into the ALBA storage ring presently uses a conventional local injection bump with four dipole kickers. However, following the promising results of the first tests with single multipole kicker injection at other light sources, studies to implement this new injection scheme have been started for ALBA. Two possible designs for the kicker have been considered: a pure octupole and a non-linear magnet similar to the BESSY type. A comparison between the expected performances of the two kicker designs has been carried out in terms of injection efficiency and transparency for the users. This paper summarises the beam dynamics results from multi-particle tracking simulations and the proposed kicker magnet design.
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THPMF013	The Stripline Kicker Prototype for the CLIC Damping Rings at ALBA: Installation, Commissioning and Beam Characterisation	extraction, storage-ring, synchrotron, impedance	4062
	M. Pont, N. Ayala, M. Carlà, T.F.G. Günzel, U. Iriso, Z. Martí, R. Monge, A. Olmos, F. Pérez, M. Quispe ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain M.J. Barnes, C. Belver-Aguilar, Y. Papaphilippou CERN, Geneva, Switzerland
	The extraction system for the CLIC Damping Rings has very tight specifications. Therefore a full characterisation of the behaviour of the stripline kicker under conditions as close as possible to the expected working conditions will be very valuable. To that end the CLIC stripline has been installed in the ALBA Synchrotron Light Source and has been characterised with beam. Prior to its installation, the effect of the stripline kicker on the machine impedance has been assessed. The installation has required the design of an absorber to screen the stripline from synchrotron radiation and additional BPMs have been installed for a better kick angle determination. The commissioning of the stripline with beam has been performed following closely beam parameters, pressure and temperature. The studies with beam include the determination of the longitudinal and transverse impedance of the kicker, the field homogeneity when excited with a dc field and the field ripple when pulsed. This contribution reports on the first experience with the stripline kicker for the CLIC DR in the ALBA storage ring and presents the results of the initial beam characterisation. M. Carla et al., "Beam based impedance measurements of the CLIC stripline at ALBA", Proc. of IPAC'2017.
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THPMF030	VSR Injector Upgrade at BESSY II	booster, cavity, injection, storage-ring	4110
	T. Atkinson, P. Goslawski, J.G. Hwang, M. Ries HZB, Berlin, Germany T. Flisgen, T. Mertens Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Berlin, Germany
	BESSY VSR is a fully funded project at the Helmholtz-Zentrum in Berlin (HZB). The objective is to produce simultaneously both long and short pulses in the storage ring. The implications for the existing injector systems and the upgrade strategy are presented. Envisaged is a global upgrade which includes additional accelerating structures to reduce the bunch length in the booster, orbit measurements and implementing longitudinal feedback.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF030
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THPMF035	Numerical Analysis of Excitation Property of Pulse Picking by Resonant Excitation at BESSY II	betatron, synchrotron, emittance, radiation	4131
	J.G. Hwang, M. Koopmans, R. Müller, M. Ries, A. Schälicke HZB, Berlin, Germany
	The pulse picking by resonant excitation (PPRE) method is applied at BESSY II to provide pseudo single bunch operation by separating the radiation from one horizontally enlarged bunch from the light of the multi-bunch filling. The bunch is enlarged by an excitation with an external signal close to the tune resonance. The variation of the beam size depends strongly on the frequency and amplitude of the excitation signal. In this paper we show the properties of the PPRE bunch studied by analytical modeling and numerical calculations using Elegant. The simulation results are compared with beam size measurements using a new interferometry beam size monitor at BESSY II.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF035
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THPMF036	Status of the Conceptual Design of ALS-U	lattice, emittance, vacuum, cavity	4134
	C. Steier, A.P. Allézy, A. Anders, K.M. Baptiste, E.S. Buice, K. Chow, G.D. Cutler, S. De Santis, R.J. Donahue, D. Filippetto, J.P. Harkins, T. Hellert, M.J. Johnson, J.-Y. Jung, S.C. Leemann, D. Leitner, M. Leitner, T.H. Luo, H. Nishimura, T. Oliver, O. Omolayo, J.R. Osborn, G.C. Pappas, S. Persichelli, M. Placidi, G.J. Portmann, S. Reyes, D. Robin, F. Sannibale, C. Sun, C.A. Swenson, M. Venturini, S.P. Virostek, W.L. Waldron, E.J. Wallén LBNL, Berkeley, California, USA
	Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The ALS-U conceptual design promises to deliver diffraction limited performance in the soft x-ray range by lowering the horizontal emittance to about 70 pm rad resulting in two orders of brightness increase for soft x-rays compared to the current ALS. The design utilizes a nine bend achromat lattice, with reverse bending magnets and on-axis swap-out injection utilizing an accumulator ring. This paper shows some aspects of the completed conceptual design of the accelerator, as well as some results of the R&D program that has been ongoing for the last years.
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THPMF042	Beam Based Measurement of Injection Parameters at KEK-PF	injection, septum, beam-transport, storage-ring	4152
	K. Hirano Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan K. Harada, N. Higashi, Y. Kobayashi, S. Nagahashi, T. Obina, R. Takai, H. Takaki, A. Ueda KEK, Ibaraki, Japan
	KEK-PF is a 2.5 GeV synchrotron radiation facility. In recent years, the injection efficiency using conventional pulsed septum and kicker magnets has decreased. The main cause of this problem seems to be the change of the injection parameters due to the accumulation of the errors including the effect of the earthquake on March 11, 2011. For the improvement of the injection efficiency, the precise and detailed parameters of the beam injection under present configuration are essential. In order to fix these parameters, we measure the response of the pulsed magnets by using injected and stored beams. In this presentation, we show the beam based measurement and the simulation results for the PF ring injection system.
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THPMF052	The Swap-Out Injection Scheme for the High Energy Photon Source	injection, booster, storage-ring, extraction	4178
	Z. Duan, J. Chen, Y.Y. Guo, Y. Jiao, J.L. Li, Y.M. Peng, J.Q. Wang, N. Wang, G. Xu, H.S. Xu IHEP, Beijing, People's Republic of China
	Funding: Work supported by Natural Science Foundation of China (No.11605212). The on-axis swap-out scheme is a promising injection scheme for di raction-limited storage rings, since it only re- quires a rather small dynamic aperture and thus potentially allows a higher brightness compared to traditional o -axis injection schemes. However, a full charge injector is neces- sary for this scheme and its design can be nontrivial, in par- ticular to satisfy the large single bunch charge requirements in special lling patterns for timing experiments. In the High Energy Photon Source, we propose using the booster also as a high energy accumulator ring to recapture the spent bunches extracted from the storage ring, so as to relax the challenges in generation and acceleration of bunches with a high charge, and as a cost-e ective solution compared to building a dedicated full energy accumulator ring. In this paper, the beam dynamics issues of this scheme will be presented, trade-o s between the storage ring and booster beam parameters and hardware specifications will also be discussed.
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THPMK069	Design of the Beam Switchyard of a Soft X-ray FEL User Facility in Shanghai	FEL, linac, undulator, dipole	4456
	S. Chen, H.X. Deng, C. Feng, B. Liu, D. Wang, R. Wang SINAP, Shanghai, People's Republic of China
	A soft X-ray FEL user facility, which is based on the existing test facility located in the Zhangjiang Campus of SINAP, is under construction. Two undulator lines will be installed parallelly in the undulator hall and their electron beams are served by a 1.5 GeV linac. For simultaneous operation of the two undulator lines, a beam distribution system should be used to connect the linac and the undulator lines. In this paper, the physics design of this beam distribution system will be presented and also the beam dynamic issues will be discussed.
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THPML093	New Fast Kicker Results from the Muon g-2 E-989 Experiment at Fermilab	experiment, monitoring, simulation, MMI	4879
	A.P. Schreckenberger The University of Texas at Austin, Austin, Texas, USA D. Barak, C.C. Jensen, G.E. Krafczyk, R.L. Madrak, H. Nguyen, H. Pfeffer, M. Popovic, J.C. Stapleton, C. Stoughton Fermilab, Batavia, Illinois, USA A.T. Chapelain, A.A. Mikhailichenko, D. L. Rubin Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA N.S. Froemming CENPA, Seattle, Washington, USA J.L. Holzbauer UMiss, University, Mississippi, USA A.I. Keshavarzi The University of Liverpool, Liverpool, United Kingdom
	We describe the installation, commissioning, and characterization of the injection kicker system for the E-989 experiment at Fermilab for a precision measurement of the muon anomalous magnetic moment. Control and monitoring systems have been implemented to acquire and record the waveforms of each kicker pulse, and measurements of various kicker system observables were recorded in the presence of the 1.45 T g-2 storage ring magnetic field. These monitoring systems are necessary to understand the systematic contribution to the measurement of the precession frequency. We examine the dependence of muon capture to kicker field predictions.
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THPML095	Improvement of Wire-Stretching Technique to the RF Measurements of E-Center and Multipole Field for the Dipole Cavities	cavity, coupling, simulation, electron	4885
	G.-T. Park, J. Guo, H. Wang JLab, Newport News, Virginia, USA A. Overstreet ODU, Norfolk, Virginia, USA B. P. Xiao, T. Xin BNL, Upton, Long Island, New York, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. After the first publication* of wire-stretching technique from its principle to measure the electrical center of a deflecting cavity, more refinements of this techniques including the review of its analytical and simulation results, RF circuit improvement to improve the signal to noise ratio and its application to other cavities have been developed. These applications include the electrical center measurements for the LHC RFD and DQW crabbing cavity prototypes, multi-frequency harmonic kicker cavity for JLEIC electron cooler, TE011 cavity developed for the beam magnetization measurement, and a separator cavity at BNL**. Further development of measurement calibration, error reduction, alignment of cavity installation to the machine beam line, and multipole field analysis for the beam dynamics will be presented. H. Wang, Proceedings of NAPAC2016, pp225-228 S. A. Overstreet, BS Thesis 2017, Guilford College, Greensboro, NC J. Guo et al. these proceedings ***T. Xin et al, these proceedings
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THPML116	AutoTuner: A General Graphical User Interface for Automated Tuning	GUI, interface, controls, target	4939
	X. Huang SLAC, Menlo Park, California, USA T. Zhang USTC/NSRL, Hefei, Anhui, People's Republic of China
	AutoTuner is a general graphical user interface (GUI) that we developed for automated tuning or online optimization. The GUI provides a convenient interface to select tuning knobs, objectives, and optimization algorithms and to change the tuning control parameters. Tuning setup can be created and saved for reuse. The progress of the tuning processing is plotted in real time. The tuning process can be paused, aborted, or resumed. We have tested the program for real-life accelerator tuning problems.
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THPML138	Efficiency and Error Analysis of the HALS Injection Scheme	injection, simulation, lattice, storage-ring	5008
	Z.B. Sun, G. Liu, W. Liu, F.L. Shang, L. Shang, W.B. Song USTC/NSRL, Hefei, Anhui, People's Republic of China
	Hefei Advanced Light Source (HALS) is a newly designed diffraction-limited storage ring.. The latest version of HALS has a 7BA lattice. One of the most important parts about HALS design is its injection system. Since conventional injection scheme is not suitable for DLSRs, many new injection schemes are proposed, including longitudinal injection scheme. In this paper, we investigate the feasibility of longitudinal injection scheme for HALS. In order to evaluate the injection performance, various errors have been considered. A series of tracking simulations are carried out and injection efficiency is obtained under different error levels.
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FRXGBD1	Reliability and Availability of Particle Accelerators: Concepts, Lessons, Strategy	operation, luminosity, collider, beam-losses	5014
	A. Apollonio, L. Ponce, O. Rey Orozko, R. Schmidt, A.P. Siemko, B. Todd, J.A. Uythoven, A.P. Verweij, D. Wollmann, M. Zerlauth CERN, Geneva, Switzerland
	This paper will present the results and latest status of an extensive effort to analyse and improve the reliability and availability of the LHC. After the introduction of basic concepts and definitions, the paper reviews the performance of the LHC in 2015-2017. A direct comparison of the luminosity production years 2016 and 2017 is presented, with a focus on the main differences in the observed failure modes. Based on the lessons learnt in this time window, expectations for the performance during future LHC runs are discussed. In particular, the thought process for the evaluation of the possible full energy exploitation of the LHC is described, considering relevant factors such as the expected availability loss and the risk associated to magnet training.
	Slides FRXGBD1 [7.090 MB]
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FRXGBD2	Fast Kicker for High Current Beam Manipulation: Experimental Facility	experiment, simulation, septum, electron	5019
	V.V. Gambaryan, A.A. Starostenko BINP SB RAS, Novosibirsk, Russia A.A. Starostenko NSU, Novosibirsk, Russia
	The pulsed deflecting magnet (kicker) project was worked out in Budker Institute of Nuclear Physics. The kicker design parameters are: impulsive force, 1 mT*m; pulse edge, 5 ns; impulse duration, 200 ns. The unconventional approach is that the plates must be replaced by a set of cylinders. The obtained magnet construction enables the field homogeneity to be controlled by changing current magnitudes in cylinders. Furthermore, we demonstrated the method of field optimization. In addition, measurement technique for the harmonic components was considered and the possibility of control harmonic components value was demonstrated. The results with electron beam on actual facility was considered.
	Slides FRXGBD2 [4.864 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-FRXGBD2
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Paper

Title

Other Keywords

Page

MOPMF062

Upgrade of the Dilution System for HL-LHC

operation, Windows, damping, simulation

261

C. Wiesner, W. Bartmann, C. Bracco, M. Calviani, E. Carlier, L. Ducimetière, M.I. Frankl, M.A. Fraser, S.S. Gilardoni, B. Goddard, T. Kramer, A. Lechner, N. Magnin, A. Perillo-Marcone, T. Polzin, E. Renner, V. Senaj
CERN, Geneva, Switzerland

The LHC Beam Dump System is one of the most critical systems for reliable and safe operation of the LHC. A dedicated dilution system is required to sweep the beam over the front face of the graphite dump core in order to reduce the deposited energy density. The High Luminosity Large Hadron Collider (HL-LHC) project foresees to increase the total beam intensity in the ring by nearly a factor of two, resulting in a correspondingly higher energy deposition in the dump core. In this paper, the beam sweep pattern and energy deposition for the case of normal dilution as well as for the relevant failure cases are presented. The implications as well as possible mitigations and upgrade measures for the dilution system, such as decreasing the pulse-generator voltage, adding two additional kickers, and implementing a retrigger system, are discussed.

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MOPMK015

Development of a Bunched-Beam Electron Cooler for the Jefferson Lab Electron-Ion Collider

electron, linac, gun, cathode

382

S.V. Benson, Y.S. Derbenev, D. Douglas, F.E. Hannon, A. Hutton, R. Li, R.A. Rimmer, Y. Roblin, C. Tennant, H. Wang, H. Zhang, Y. Zhang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S.DOE Contract No. DE-AC05-06OR23177.
Jefferson Lab is in the process of designing an electron-ion collider with unprecedented luminosity at a 65 GeV center-of-mass energy. This luminosity relies on ion cooling in both the booster and the storage ring of the accelerator complex. The cooling in the booster will use a conventional DC cooler similar to the one at COSY. The high-energy storage ring, operating at a momentum of up to 100 GeV/nucleon, requires novel use of bunched-beam cooling. We will present a new design for a Circulator Cooler Ring for bunched-beam electron cooling. This requires the generation and transport of very high-charge magnetized bunches, acceleration of the bunches in an energy recovery linac, and transfer of these bunches to a circulating ring that passes the bunches 11 times through the proton or ion beam inside cooling solenoids. This design requires the suppression of the effects of space charge and coherent synchrotron radiation using shielding and RF compensation.

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MOPML025

Slow Extraction Optimization at the MedAustron Ion Therapy Center: Implementation of Front End Acceleration and RF Knock Out

extraction, proton, acceleration, synchrotron

453

A. De Franco, L. Adler, F. Farinon, N. Gambino, G. Guidoboni, G. Kowarik, M. Kronberger, C. Kurfürst, S. Myalski, S. Nowak, M.T.F. Pivi, C. Schmitzer, I. Strašík, P. Urschütz, A. Wastl
EBG MedAustron, Wr. Neustadt, Austria
L.C. Penescu
Abstract Landscapes, Montpellier, France

Funding: This project has received funding from the European Union's Horizon 2020 research and Innovation programme under the Marie Skłodowska-Curie grant agreement No 675265.
MedAustron is a synchrotron-based ion therapy center allowing tumour treatment with protons and other light ion species, in particular C⁶⁺. Commissioning of all fixed lines, two horizontal and one vertical, has been completed for protons and in parallel to the commissioning of a gantry and C⁶⁺, a facility upgrade study is progressing. The upgrade study encompasses the optimization of the slow extraction mechanism by employing the RF empty bucket channeling and RF Knock Out techniques. The former is a front end acceleration technique that suppress spill ripples, fundamental to safely operate the machine at the highest intensities. The latter is an alternative extraction technique which opens up interesting possibilities for fast beam energy and intensity modulations. In this work, we quantify spill smoothening effect achieved with the first and report the results of a feasibility study of the second using a Schottky monitor as a transverse kicker.

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MOPML030

Demonstration of a Tunable Electron Beam Chopper for Application in 200 kV stroboscopic TEM

electron, laser, experiment, controls

467

C.-J. Jing, S.V. Baryshev, A. Kanareykin, A. Liu, Y. Zhao
Euclid TechLabs, LLC, Solon, Ohio, USA
J.W. Lau
NIST, Gaithersburg, Maryland, USA
D. Masiel, B. Reed
Integrated Dynamic Electron Solutions, Pleasanton, California, USA
Y. Zhu
BNL, Upton, Long Island, New York, USA

Funding: The project is supported by the Office of Basic Energy Science of DOE through a Small Business Innovative Research grant #DE-SC0013121.
For the last several decades, time-resolved transmission electron microscopes (TEM) exploring the sub-microsecond timescale have relied on the photoemission technology to generate the single or train of electron bunches. However, the complexity of additional laser system and the availability of high repitition rate laser limit applications of the laser-driven approach. Lately we have made substantial progress towards pioneering a new kind of time-resolved TEM, complementary to the existing laser-based techniques. Using a tunable RF beam-chopper, we are able to retrofit an exsiting TEM providing a pulsed electron beam at a continuously tunable reptition rate up to 12GHz and a tunable bunch length. In the article we will briefly discuss the working principle and experimental progress to date.

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TUXGBF3

Reduction of the Kicker Impedance Maintaining the Performance of Present Kicker Magnet at RCS in J-PARC

impedance, simulation, synchrotron, extraction

616

Y. Shobuda, Y. Irie, T. Takayanagi, T. Togashi, K. Yamamoto, M. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The present kicker at RCS in J-PARC is designed to make a waveform by superposing the forward and backward currents from the power source to extract beams, so that one terminal of the kicker is shorted and the other one is open. On the other hand, the kicker impedance is the dominant source of the beam instability at the RCS. This report proposes a scheme to reduce the kicker impedance, maintaining the beneficial of the superposition of currents with the present kicker magnet.

Slides TUXGBF3 [9.947 MB]

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TUPAF027

CERN PS Kicker for Proton Injection: from Beam-Based Waveform Measurements to Hardware Improvements

simulation, injection, emittance, flattop

732

V. Forte, A. Ferrero Colomo, M.A. Fraser, T. Kramer
CERN, Geneva, Switzerland

For 2017 operation, the termination mode of the CERN Proton Synchrotron (PS) horizontal injection kicker was permanently changed to short-circuited, to be compliant with the future performances requested by the LHC Injectors Upgrade (LIU) project. An extensive campaign of measurements was performed through a dedicated beam-based technique. The measurements identified possibilities for optimisation of the kicker system and were fundamental to properly tune the PSpice simulation model of the kicker, as well as for validating the hardware changes. The model was finally used to estimate the horizontal emittance growth for the future injection schemes in the PS.

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TUPAF028

Energy Deposition Studies and Analysis of the Quench Behavior in the Case of Asynchronous Dumps During 6.5 TeV LHC Proton Beam Operation

simulation, superconducting-magnet, proton, quadrupole

736

M.I. Frankl, W. Bartmann, M. Bednarek, C. Bracco, A. Lechner, A.P. Verweij, C. Wiesner, D. Wollmann
CERN, Geneva, Switzerland

The CERN LHC beam dumping system comprises a series of septa and fast-pulsed kicker magnets for extracting the stored proton beams to the external beam dumps. Different absorbers in the extraction region protect superconducting magnets and other machine elements in case of abnormal beam aborts, where bunches are swept across the machine aperture. During Run 2 of the LHC, controlled beam loss experiments were carried out at 6.5 TeV probing the particle leakage from protection devices under realistic operation conditions. This paper presents particle shower simulations analyzing the energy deposition in superconducting coils and assessing if the observed magnet quenches are compatible with the presently known quench limits.

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TUPAF031

Beam Simulation Studies for the Upgrade of the SPS Beam Dumping System

simulation, dumping, operation, injection

747

C. Heßler, W. Bartmann, E. Carlier, L. Ducimetière, B. Goddard, F.M. Velotti
CERN, Geneva, Switzerland

The SPS at CERN currently uses a beam dumping system that is installed in the long straight section 1 (LSS1) of the SPS. This system consists of two beam stopper blocks for low and high energy beams, as well as two vertical and three horizontal kicker magnets, which deflect and dilute the beam on the dumps. Within the frame of the LHC injector upgrade project (LIU) the beam dumping system will be relocated to long straight section 5 (LSS5) and upgraded with an additional vertical kicker, new main switches and a single new beam dump, which covers the full energy range. The impact of a possible increase of the vertical kicker rise time on the beam has been studied in simulations with MAD-X for the different optics in the SPS. Furthermore, the impact on the beam in failure scenarios such as the non-firing of one kicker has been investigated. The results of these studies will be presented and discussed in this paper. Operational mitigation methods to deal with an increased rise time will also be discussed.

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TUPAF058

Optimization of the FCC-hh Beam Extraction System Regarding Failure Avoidance and Mitigation

extraction, hardware, collider, septum

850

E. Renner, M.J. Barnes, W. Bartmann, F. Burkart, E. Carlier, L. Ducimetière, B. Goddard, T. Kramer, A. Lechner, N. Magnin, V. Senaj, J.A. Uythoven, P. Van Trappen, C. Wiesner
CERN, Geneva, Switzerland

A core part of the Future Circular Collider (FCC) study is a high energy hadron-hadron collider with a circumference of nearly 100~km and a center of mass beam energy of 100~TeV. The energy stored in one beam at top energy is 8.3~GJ, more than 20 times that of the LHC beams. Due to the large damage potential of the FCC-hh beam, the design of the beam extraction system is dominated by machine protection considerations and the requirement of avoiding any material damage in case of an asynchronous beam dump. Erratic operation of one or more extraction kickers is a main contributor to asynchronous beam dumps. The presented study shows ways to reduce the probability and mitigate the impact of erratic kicker switching. Key proposals to achieve this include layout considerations, different hardware options and alternative reaction strategies in case of erratic extraction kicker occurrence. Based on these concepts, different solutions are evaluated and an optimized design for the FCC-hh extraction system is proposed.

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TUPAF059

Design and Evaluation of FCC-hh Injection Protection Schemes

injection, dipole, collider, collimation

854

E. Renner, M.J. Barnes, W. Bartmann, C. Bracco, R. Bruce, F. Burkart, B. Goddard, A. Lechner, L.S. Stoel, F.M. Velotti, C. Wiesner, D. Woog
CERN, Geneva, Switzerland

The Future Circular Collider (FCC) study considers several injector scenarios for FCC-hh, the proposed 100~TeV centre of mass hadron collider located at CERN. The investigated options include amongst others to use the LHC at 3.3~TeV or a superconducting SPS at 1.3~TeV as a High Energy Booster (HEB). Due to the high energy of the injected proton beam and the short time constant of injection failures, a thorough consideration of potential failure cases is of major importance. Further attention has to be given to the fact that the injection is - as in LHC - located upstream of the side experiments. Failure scenarios are identified for both injector options, appropriate designs of injection protection schemes are proposed and first simulations are conducted to validate the protection efficiency.

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TUPAF060

Injection and Dump Systems for a 13.5 TeV Hadron Synchrotron HE-LHC

injection, extraction, septum, experiment

858

W. Bartmann, M.J. Barnes, L. Ducimetière, B. Goddard, M. Hofer, T. Kramer, A. Lechner, E. Renner, A. Sanz Ull, V. Senaj, L.S. Stoel, C. Wiesner
CERN, Geneva, Switzerland

One option for a future circular collider at CERN is to build a 13.5 TeV hadron synchrotron, or High Energy LHC (HE-LHC) in the LHC tunnel. Injection and dump systems will have to be upgraded to cope with the higher beam rigidity and increased damage potential of the beam. The required modifications of the beam transfer hardware are highlighted in view of technology advancements in the field of kicker switch technology. An optimised straight section optics is shown.

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TUPAF076

Design of PIP-II Medium Energy Beam Transport

vacuum, SRF, linac, cryomodule

905

A. Saini, C.M. Baffes, A.Z. Chen, V.A. Lebedev, L.R. Prost, A.V. Shemyakin
Fermilab, Batavia, Illinois, USA

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-II (PIP-II) is a proposed upgrade for the accelerator complex at Fermilab. The central piece of PIP-II is a superconducting radio frequency (SRF) 800 MeV linac capable of operating in both CW and pulse regimes. The PIP-II linac comprises a warm front-end that includes a H⁻ ion source capable of delivering 15-mA, 30-keV DC or pulsed beam, a Low Energy Beam Transport (LEBT), a 162.5 MHz, CW Radio-Frequency Quadrupole (RFQ) accelerating the ions to 2.1 MeV and, a 14-m Medium Energy Beam Transport (MEBT) before beam is injected into SRF part of the linac. This paper presents the PIP-II MEBT design and, discusses operational features and considerations that lead to existing optics design such as bunch by bunch chopping system, minimization of radiation coming to the warm front-end from the SRF linac using a concrete wall, a robust vacuum protection system etc.

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TUPAF078

Recent Results of HESR Original Stochastic Cooling Tanks at COSY

pick-up, experiment, storage-ring, hardware

913

R. Stassen, B. Breitkreutz, N. Shurkhno
FZJ, Jülich, Germany

The High Energy Storage Ring (HESR) of the FAIR project at GSI Darmstadt will be very important for different scientific programs due to the modularized start version of FAIR. Stochastic cooling together with barrier bucket operation will be the key component to fulfill the requirements of the different experiments. First pickup and first kicker of the HESR stochastic cooling system have been installed into the COSY accelerator at FZJ Jülich. COSY is well suited to test the performance of the HESR stochastic cooling hardware at different energies and variable particle numbers. The novel dedicated HESR-structures were already successfully tested at the Nuclotron in Dubna for longitudinal cooling and during a beam time 2017 for transverse cooling at COSY. The results of the last stochastic cooling beam time will be presented as well as the first use of GaN based amplifiers in a stochastic cooling system. The HESR needs fast transmission-lines between PU and KI. Beside air-filled coax-lines, optical hollow fiber-lines are very attractive. First results with such a hollow fiber used for the transverse signal path will be presented.

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TUPAL068

The Development of a Nw Fast Harmonic Kicker for the JLEIC Circulator Cooling Ring

cavity, emittance, simulation, electron

1171

G.-T. Park, F. Fors, J. Guo, R.A. Rimmer, H. Wang, S. Wang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
After the first half-scale, 5 harmonic kicker cavity prototyping * for the JLEIC's CCR/ERL electron cooler and the beam dynamic simulation study of the 10-turn CCR **. The optimized circulation cooling turns has been changed to 11 and only 5 odd-harmonic modes from 86.6 MHz to 779.4 MHz plus a DC bias are needed for the harmonic RF kicker system. The new cavity design including the electromagnetic and thermal cooling optimization and its 11 turns beam bunch tracking simulation with the new numerology of RF deflecting voltages will be presented. Further design specifications for its RF harmonic drive and the broadband RF window, coupler and circulator component will be given for handling 5 kW of total RF power.
* Y, Huang, H. Wang et al., Physical Review Accelerators and Beams 19, 122001 (2016).
** Y. Huang, H. Wang et al., Physical Review Accelerators and Beams 19, 084201 (2016).

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TUZGBD2

Transverse and Longitudinal Bunch-by-Bunch Feedback for Storage Rings

feedback, timing, FPGA, damping

1198

T. Nakamura
JASRI/SPring-8, Hyogo-ken, Japan

Digital bunch-by-bunch feedback systems for betatron and synchrotron oscillation are powerful tools for suppression of beam instabilities and are indispensable for stable operation of storage rings. This invited talk reviews the world activities on transvers and longitudinal bunch-by-bunch feedback for storage rings.

Slides TUZGBD2 [15.900 MB]

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TUZGBD4

Impact of a Wideband Feedback Prototype System on TMCI in the SPS

feedback, optics, injection, emittance

1208

W. Höfle, H. Bartosik, E.R. Bjørsvik, G. Kotzian, T.E. Levens, K.S.B. Li
CERN, Geneva, Switzerland
J.E. Dusatko, J.D. Fox, C.H. Rivetta
SLAC, Menlo Park, California, USA
O. Turgut
Stanford University, Stanford, California, USA

The transverse mode coupling instability (TMCI) in the SPS has been identified as one of the potential performance limitations for future high intensity LHC beams that will be required for the High Luminosity (HL)-LHC era and is being addressed by the LHC Injector Upgrade Project (LIU). A potential mitigation can be provided by wideband feedback systems with a frequency reach of about 1 GHz . For this reason, the development of a prototype system has been started in a CERN collaboration within the US-LARP framework in 2008. In this report we present latest experimental results in 2017 where this prototype system was used in single and multi-bunch studies. In particular, a successful mitigation against TMCI at injection could be demonstrated in single bunch studies.

Slides TUZGBD4 [15.116 MB]

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TUZGBD5

Performance of Nanometre-Level Resolution Cavity Beam Position Monitors at ATF2

cavity, feedback, dipole, electron

1212

T. Bromwich, D.R. Bett, N. Blaskovic Kraljevic, R.M. Bodenstein, P. Burrows, G.B. Christian, C. Perry, R.L. Ramjiawan
JAI, Oxford, United Kingdom
S. Araki, A. Aryshev, T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan
P. Bambade, S. Wallon
LAL, Orsay, France
S.W. Jang
Korea University Sejong Campus, Sejong, Republic of Korea

A system of three low-Q cavity beam position monitors (BPMs), installed in the interaction point (IP) region of the Accelerator Test Facility (ATF2) at KEK, has been designed and optimised for nanometre-level beam position resolution. The BPMs are used to provide an input to a low-latency, intra-train beam position feedback system deployed in single-pass, multi-bunch mode with the aim of demonstrating intra-train beam stabilisation on electron bunches of charge ~1 nC separated in time by 280 ns. In 2016 the BPM resolution was demonstrated to be below 50 nm using the raw measured vertical positions at the three BPMs. New results will be presented utilising integrated sampling of the raw waveforms, improved BPM alignment and modified cavities to demonstrate a vertical position resolution on the order of 20 nm.

Slides TUZGBD5 [8.557 MB]

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TUPMF014

Synchrotron Accumulation on Off-Energy Closed-Orbit with Anti-Septum or Nonlinear Kicker

injection, septum, accumulation, closed-orbit

1280

Y.P. Sun
ANL, Argonne, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Off-axis accumulation on off-energy closed-orbit (so-called synchrotron injection/accumulation) was studied and implemented in the 1990s for LEP at CERN. The idea of using pulsed multipole injection on off-energy closed-orbit was first proposed in 2014 and then developed for Swiss Light Source (SLS) upgrade in 2015. In 2017, the anti-septum was proposed for SLS upgrade injection. In this paper, two similar injection schemes are proposed which combine off-axis accumulation on off-energy closed-orbit (no betatron oscillations), with the anti-septum or pulsed nonlinear kicker schemes. Preliminary lattice solutions are developed for Advanced Photon Source upgrade (APS-U) where a special injection straight (with length of 5.8 m) is designed with horizontal dispersion of 0.15m. The impact on the ring emittance is relatively small. The injection elements are all placed in this injection straight, including 1 thin septum and 3 slow kickers (or 1 pulsed nonlinear kicker). No fast kickers are needed.

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TUPMF017

Transport Line Design and Injection Configuration Optimization for the Advanced Photon Source Upgrade

injection, septum, dipole, emittance

1287

A. Xiao, M. Borland
ANL, Argonne, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
On-axis swap-out injection was chosen for the Advanced Photon Source Upgrade (APS-U) to allow pushing the beam emittance to an extremely low value. The injection section configuration was optimized within a multi-dimensional parameter space and made consistent with up-to-date technical developments. The booster-to-storage ring (BTS) transport line was designed to bring the electron beam from the existing Booster to the new storage ring (SR). Due to various limitations, this new BTS line is twisted both horizontally and vertically when approaching the injection point, which introduces challenges in both geometrical and optical matching. This paper presents our simple solution to these issues. The coupling effect caused by the twisted BTS line is also discussed.

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TUPMF046

The Injection and Extraction Design of the Booster for the HEPS Project

injection, extraction, storage-ring, booster

1356

Y.Y. Guo, J. Chen, Z. Duan, Y. Jiao, Y.M. Peng, G. Xu
IHEP, Beijing, People's Republic of China

The HEPS booster is a 1Hz electron synchrotron. It accelerates electron bunches from 500 MeV to final energy of 6 GeV. The vertical scheme was chosen for the injection and extraction system of the booster. What's more, an injection system from storage ring is required. The layout of the injection and extraction system were introduced in this paper. The parameter optimization and other considerations are presented in detail.

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TUPMF053

Longitudinal Impedance Measurement of the Strip-Line Kicker for High Energy Photon Source (HEPS)

impedance, simulation, coupling, distributed

1379

S.K. Tian, J. Chen, Y. Jiao, H. Shi, L. Wang, N. Wang
IHEP, Beijing, People's Republic of China

The High Energy Photon Source (HEPS) is a 6-GeV, kilometer-scale storage ring light source to be built in China. One of the main design challenges of the storage ring is to minimize collective instabilities associated with the impedance of small-aperture vacuum components. In this paper we present beam coupling impedance measurements obtained by the well known coaxial wire method, for the HEPS Strip-Line kicker. The frequency dependent real and imaginary parts of the distributed impedance are obtained from the measured S-parameters.

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TUPMF084

Optimization of the Injection Kicker Bump Leakage at PETRA III

injection, septum, feedback, electron

1467

J. Keil, G. Kube, F. Obier, G.K. Sahoo, R. Wanzenberg
DESY, Hamburg, Germany

PETRA III is a third generation synchrotron light source at DESY delivering high brightness photon beams for users at 21 beam lines. It is operated at 6 GeV with a beam current of 100 mA in top-up mode and is in operation for users since 2010. An off-axis injection scheme is used to accumulate beam from the booster synchrotron DESY II in PETRA III. Three fast injection kicker magnets generate a closed orbit bump for one turn to move the stored beam near to the injection septum magnet. Ideally the orbit bump generated by the 10 μs long half-sine pulses of the kickers should be closed. Due to differences in pulse shape as well as timing and amplitude errors of the pulses there is some leakage of the injection bump which disturbs the closed orbit and affects the beam quality during top-up operation. Turn-by-turn data from the beam position monitor (BPM) system of PETRA III have been used to measure the bump leakage for different bucket positions in the filling pattern. The procedure to reduce the injection kicker bump leakage and the achieved improvement will be discussed.

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TUPMK001

Removal of RF-Fingers at the Edges of the Injection Kickers

impedance, resonance, storage-ring, injection

1485

T.F.G. Günzel, N. Ayala, F.F.B. Fernández, U. Iriso, M. Pont
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

The ALBA storage ring injection kickers are equipped with RF-fingers to close a 2.5 mm gap between the ceramic tube and the metallic flange. After two distortion incidents that required the replacement of the fingers, their removal was decided. The decision could be supported by the observation that most of the additional impedance is created above the cut-off frequency of the beam pipe. This was later confirmed by a temperature decrease in that zone after the removal. Furthermore it was checked that the thresholds of the longitudinal coupled bunch instabilities of modes trapped around the resulting open gap are above the maximal applied beam current of 400 mA.

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TUPMK004

Using Decoherence to Prevent Damage to the Swap-Out Dump for the APS Upgrade

simulation, emittance, electron, storage-ring

1494

M. Borland, J.C. Dooling, R.R. Lindberg, V. Sajaev, A. Xiao
ANL, Argonne, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The Advanced Photon Source (APS) is pursuing an upgrade of the storage ring to a hybrid seven-bend-achromat* design, which will operate in swap-out mode. The ultra-low emittance (about 30 pm in both planes) combined with the desire to provide high charge (15 nC) in individual bunches, entails very high energy density in the beam. Simple estimates, confirmed by simulation, indicate that interaction of such a bunch with the dump material will result in localized melting. Over time, it is possible that the beam would drill through the dump and vent the ring vacuum. This would seem to prevent extraction and dumping of bunches as part of swap out, and also suggests that transferring of bunches out of the ring carries significant risk. We devised an idea for using a pre-kicker to cause decoherence of the target bunch emittances, making it safe to extract. Simulations show that the concept works very well.
*L. Farvacque et al., IPAC13, 79 (2013).

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TUPML064

Staged Two Beam Acceleration Beam Line Design for the AWA Facility

experiment, gun, laser, acceleration

1688

N.R. Neveu
IIT, Chicago, Illinois, USA
W. Gai, C.-J. Jing, J.G. Power
ANL, Argonne, Illinois, USA
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
L.K. Spentzouris
Illinois Institute of Technology, Chicago, Illinois, USA

Funding: This work is funded by the DOE Office of Science, grant no. DE-SC0015479, and contract No. DE-AC02- 06CH11357.
Two beam acceleration is a candidate for future high energy physics machines and FEL user facilities. This scheme consists of two independent electron beam lines operating synchronously. High-charge, 70 MeV drive bunch trains are injected from the RF photo-injector into decelerating structures to generate a few hundred of MW of RF power. This RF power is transferred through an RF waveguide to accelerating structures that are used to accelerate the witness beam. Staging refers to the sequential acceleration (energy gain) in two or more structures on the witness beam line. A kicker was incorporated on the drive beam line to accomplish a modular design so that each accelerating structure can be independently powered by a separate drive beam. Simulations were performed in OPAL-T to model the two beam lines. Beam sizes at the center of the structures was minimized to ensure good charge transmission. The resulting design will be the basis for proof of principle experiments that will take place at the Argonne Wakefield Accelerator (AWA) facility.

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WEXGBE1

Review of Top-up Injection Schemes for Electron Storage Rings

injection, synchrotron, septum, storage-ring

1745

M. Aiba
PSI, Villigen PSI, Switzerland

Top-up operation, which nowadays is standard for lepton colliders and synchrotron light sources, has been developed over last decades. The accelerator performances have been drastically improved through top-up operation. However, future electron storage rings are designed, aiming at further high performance, to operate with strong nonlinear magnetic fields that may restrict their dynamic aperture. Consequently, the conventional off-axis injection and accumulation may become impossible. New injection schemes have been proposed and under development to overcome the difficulties and limitations expected in these machines. This paper reviews top-up injection schemes, including novel ideas recently proposed.

Slides WEXGBE1 [3.584 MB]

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WEYGBF4

Development of a Solid-State Pulse Generator Driving Kicker Magnets for a Novel Injection System of a Low Emittance Storage Ring

injection, timing, high-voltage, storage-ring

1804

T. Inagaki, H. Tanaka
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
H. Akikawa, K. Sato
Nihon Koshuha Co. Ltd, Yokohama, Japan
K. Fukami, C. Kondo, S. Takano
Japan Synchrotron Radiation Research Institute (JASRI), RIKEN SPring-8 Center, Hyogo, Japan

Funding: Funded by MEXT Japan
A next generation electron storage ring represented by a diffraction-limited light source pursues an extremely low emittance leading to a small dynamic aperture and short beam lifetime. The top-up injection is hence indispensable to keep the stored beam current. The beam orbit fluctuation caused by the injection magnets should seriously obstruct utilization of an electron beam with sharp transverse profile. In order to solve these problems, a novel off-axis in-vacuum beam injection system was proposed. In the system, twin kicker magnets driven by a single solid-state pulsed power supply to launch a linear pi- bump orbit is the key to suppress the horizontal orbit fluctuation down to a level of several microns. Here, a big challenge is to achieve the magnetic field identity of the two kickers within an accuracy of 0.1%. This presentation overviews the proposed injection system and reports the development status focusing on the solid-state pulse generator.

Slides WEYGBF4 [3.062 MB]

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WEPAF055

Time-Synchronized Beam Diagnostics at SPEAR3

diagnostics, feedback, timing, injection

1948

Q. Lin, Z.H. Sun
Donghua University, Shanghai, People's Republic of China
P. Boussina, W.J. Corbett, D.J. Martin, J.A. Safranek, K. Tian
SLAC, Menlo Park, California, USA
D. Teytelman
Dimtel, San Jose, USA

The SPEAR3 timing system supplies a 10Hz trigger pulse synchronous with charge injection into the main storage ring. In the past the 10Hz pulse train has been used to study injected charge transients as seen by visible-light synchrotron radiation diagnostics and turn-by-turn BPMs. More recently the 10Hz pulse has been used to synchronize the bunch-by-bunch feedback data acquisition system with other triggered diagnostic systems. The suite of measurement systems can be used to study injected beam dynamics, grow/damp instability transients and drive/damp physics.

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WEPAF056

A Graphical User Interface for Transverse Bunch-by-Bunch Feedback at SPEAR3

feedback, interface, impedance, software

1951

K. Tian, W.J. Corbett, D.J. Martin, J.J. Sebek
SLAC, Menlo Park, California, USA
Q. Lin
Donghua University, Shanghai, People's Republic of China
D. Teytelman
Dimtel, San Jose, USA

Recently a transverse bunch-by-bunch feedback kicker was installed in SPEAR3 to control beam instabilities, remove unwanted satellite bunches and test resonant bunch excitation schemes for short pulse x-ray production. In conjunction with DIMTEL processing electronics, the feedback system can successfully stabilize undesirable beam modes and opens up the potential for more advanced investigations of bunch-by-bunch beam dynamics. To streamline the process, a graphical user interface was developed that allows the user to 'script' beam physics measurements from a single panel. At the press of a button the panel automatically downloads the measurement parameters, acquires the raw data and provides graphical displays of the beam response with calculated metadata. In this paper we present the interface format and examples of automated measurements.

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WEPAF072

Transverse Feedback System for the CERN FCC-hh Collider

injection, feedback, damping, emittance

1997

W. Höfle, J. Komppula, G. Kotzian, K.S.B. Li, D. Valuch
CERN, Geneva, Switzerland

For the future hadron Collider (FCC-hh) being studied at CERN a strong transverse feedback system is required to damp coupled bunch instabilities. This system is also planned to be used for injection damping. Based on the LHC transverse feedback design we derive requirements for power and kick strength for this system for the different options of bunch spacing, 25 ns and 5 ns, and injection energy. Operation at high gain and close to a half integer tune is being considered and constrains the layout and signal processing. Requirements for the pick-up resolution are derived from the need to keep the emittance increase small. The performance is evaluated using numerical simulations based on the headtail code. Future areas of research and development and possible prototype developments are outlined.

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WEPAK010

Simulations and Measurements of the BPM Non Linearity and Kicker Timing Influence on the Tune Shift With Amplitude (TSWA) Measurement at BESSY II

simulation, optics, factory, diagnostics

2107

F. Kramer, P. Goslawski, J.G. Hwang, A. Jankowiak, P. Kuske, M. Ruprecht, A. Schälicke
HZB, Berlin, Germany

The Tune Shift With Amplitude (TSWA) does not only determine the position of the stable fix points for the Transverse Resonant Island Buckets (TRIBs) but also represents a global observable for the nonlinear optics in general. For theoretical investigations of the TRIBs a reliable nonlinear optics of the machine is required and thus all measurable global observables for the nonlinear optics are of great interest. The measurement of the TSWA for the BESSY II standard optics was performed using an injection kicker to excite high amplitude betatron oscillations and then extract the amplitude dependant frequency from the synchrotron radiation damped oscillation with a Hilbert transformation. With TRIBs optics the injection kicker was not able to sufficienty excite the beam. The impact and correctability of the BPM nonlinearity at the reached amplitudes and the reason for the failure of the excitation method for our TRIBs optics shall be looked onto in this paper.

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WEPAL025

Development of a Low-Latency, High-Precision, Beam-Based Feedback System Based on Cavity BPMs at the KEK ATF2

feedback, cavity, dipole, extraction

2212

R.L. Ramjiawan, D.R. Bett, N. Blaskovic Kraljevic, R.M. Bodenstein, T. Bromwich, P. Burrows, G.B. Christian, C. Perry
JAI, Oxford, United Kingdom

A low-latency, intra-train feedback system employing cavity beam position monitors (BPMs) has been developed and tested at the Accelerator Test Facility (ATF2) at KEK. The feedback system can be operated with either position information from a single BPM to provide local beam stabilisation, or by using position information from two BPMs to stabilise the beam at an intermediate location. The correction is implemented using a stripline kicker and a custom power amplifier, with the feedback calculations being performed on a digital board built around a Field Programmable Gate Array (FPGA). The addition of indium sealing to the BPMs to increase the cavities' Q-values has led to improvements to the BPM system resolution, with current measurements of the resolution of order 20 nm. The feedback performance was tested with beam trains of two bunches, separated by 280 ns and with a charge of ~1 nC. For single- (two-)BPM feedback, stabilisation of the beam has been demonstrated to below 50 nm (41 nm). Ongoing work to improve the feedback performance further will be discussed.

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WEPAL036

Implementation of CSNS RCS Beam Injection and Extraction Modes in Timing System

extraction, injection, timing, linac

2247

P. Zhu, M.Y. Huang, D.P. Jin, G. Lei, G.L. Xu, Y.L. Zhang
IHEP, Beijing, People's Republic of China
L. Wang
CSNS, Guangdong Province, People's Republic of China

Funding: Institute of High Energy Physics， Chinese Academy of Sciences, Beijing 100049, China; Dong guan Neutron Science Center, Dong guan 523803, China
Based on the physical design of the accelerator and the demand of the beam research, we designed four RCS beam injection modes and two RCS beam extraction modes, each of which corresponds to a series of specific timing for the accelerator. RCS beam injection and extraction modes are implemented on "VME + customized boards" hardware platform. In this paper, we will introduce the design and implementation of RCS beam injection and extraction modes as well as the RCS timing requirements and implementation in detail.

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WEPAL055

TPS Beam Trip Analysis and Dose Distribution

radiation, SRF, neutron, storage-ring

2302

B.Y. Chen, F.Y. Chang, S. Fann, C.S. Huang, C.H. Kuo, T.Y. Lee, C.C. Liang, W.Y. Lin, Y.C. Lin, Y.-C. Liu
NSRRC, Hsinchu, Taiwan

Failure analysis during TPS users operation is im-portant to improve the performance of the TPS storage ring. In this report, we discuss the particular radiation dose patterns, relevant to different beam trips, and the development of a tool to help us analyse this dose distri-bution. We will use this analysing tool to train our ability for future failure analysis to shorten the time it takes to find the problem.

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WEPAL057

Methods to Detect Error Sources and Their Application at the TPS

photon, storage-ring, cavity, injection

2305

C.H. Huang, Y.-S. Cheng, P.C. Chiu, K.T. Hsu, K.H. Hu, C.Y. Wu
NSRRC, Hsinchu, Taiwan

For a low-emittance photon light source, beam stability is a very important property to attain a high-quality photon beam. While it is hard to avoid beam perturbations in a storage ring, it is more important to quickly find the source locations and to remove or eliminate the sources as soon as possible. In this report, we develop a method to identify the locations of multiple sources. For a source with a particular frequency, the relative phase between sources can also be obtained. This method has been a useful tool during TPS operation and its methodology and practical applications are described in this report.

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WEPAL063

A Method to Tune Pulse Magnets' Waveforms

injection, power-supply, GUI, septum

2320

T.Y. Lee, B.Y. Chen, S. Fann, C.S. Huang, C.H. Kuo, C.C. Liang, W.Y. Lin, Y.-C. Liu, Y.C. Yang
NSRRC, Hsinchu, Taiwan

Pulse magnets are used in storage ring injection kickers. The waveform of the the four kickers have strong relation with injection efficiency. A slightly offset of waveform may cause the four kickers mismatched, which would lead to storaged beam loss and decrease injection efficiency. In order to define the peak value and timing of the half-sine waveform which has noises interfering diagnosis, a curve-fitting method was introduced to monitor and fine-tuning the waveform. The waveforms' data are also archived for reference in case of replacing power supplies. By using this method, it helps to retain a consistent injection efficiency after the power supplies maintenance or replacement.

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WEPAL066

Determination of RF Resonator Axis Inclination to Beam Axis in Electron-Positron Storage Ring

experiment, resonance, electron, positron

2330

Leshenok D. Leshenok
NSU, Novosibirsk, Russia
S.A. Nikitin
BINP SB RAS, Novosibirsk, Russia

We proposed and tested the method that allows obtaining of an upper limit for an angle of the RF resonator axis inclination relative to a beam axis. Such disturbance gives an additional contribution to separation of electron and positron orbits due to action of the transverse component of the electric field. In the horizontal plane, this effect can lead to increase of the difference between electrons and positrons spin precession frequencies in a storage mono-ring collider. This effect can play a great role in FCC. At the angular disturbance of axis in the certain VEPP-4M RF resonators ~10^-3 rad, the difference between the spin frequencies is about 10^-8. Our method is based on resonant excitation of betatron oscillations using phase modulation of the master oscillator of the RF system. The maximal amplitude of the enforced oscillations is measured by the counting rate of the VEPP-4M Touschek polarimeter scintillation counters. Comparison of the obtained results with the data of the special calibration experiment allows estimating the value of the inclination angle. In this calibrated experiment the betatron oscillations excite using the VEPP-4M kicker.

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WEPAL079

Control of Intra-Bunch Vertical Motion in the SPS with GHz Bandwidth Feedback

feedback, controls, damping, injection

2365

J.D. Fox, J.E. Dusatko, C.H. Rivetta, O. Turgut
SLAC, Menlo Park, California, USA
H. Bartosik, E.R. Bjørsvik, W. Höfle, G. Kotzian, K.S.B. Li, E. Métral, B. Salvant, U. Wehrle
CERN, Geneva, Switzerland
S. De Santis
LBNL, Berkeley, California, USA

Funding: Work supported by the U.S. Department of Energy DE-AC02-76SF00515, US LHC Accelerator Research program, CERN LHC Injector Upgrade Project and the US-Japan Cooperative Program in High Energy Physics.
A GHz bandwidth vertical beam feedback system has been in development at the CERN SPS to explore control of unstable beam motion in single bunch and bunch train configurations. We present measurements and recent studies of stable and unstable motion for intensities up to 2x10¹¹ p/bunch. The system has been operated at 3.2GS/s with 16 samples across a 5 ns RF bucket (4.2 ns 3 σ bunch at injection). Experimental results confirm damping of intra-bunch instabilities in Q20, Q22 and Q26 optics configurations. Instabilities with growth times of 200 turns are well-controlled from injection, consistent with the achievable gains for the 2 installed stripline kickers with 1 kW broadband total power. Studies of the damping achieved with the diagonal FIR controllers and existing system noise floors are highlighted to evaluate benefits of MIMO feedback controllers. The work is motivated by anticipated intensity increases from the LIU and HL-LHC upgrade programs, and has included the development of a new 1 GHz bandwidth slotline kicker structure and associated amplifier system

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WEPMF020

Pulsed Systems for eRHIC Beam Injection and Extraction

injection, extraction, storage-ring, electron

2410

W. Zhang, M. Blaskiewicz, A. Hershcovitch, C.J. Liaw, H. Lovelace III, M. Mapes, G.T. McIntyre, J.-L. Mi, C. Montag, C. Pai, V. Ptitsyn, J. Sandberg, N. Tsoupas, J.E. Tuozzolo, G.M. Wang, W.-T. Weng, F.J. Willeke, H. Witte, Q. Wu
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The electron-ion collider eRHIC requires a variety of kickers and septa for injection and extraction of beams throughout the entire collider complex. We plan to use pulsed systems for beam injection and extraction in Electron RCS, Electron Storage Ring, and Hadron ring. In this paper, we describe the pulsed systems required for beam transfer in the eRHIC Ring-Ring Pre-conceptual Design. We will outline the parameter ranges, technology choices, and opportunities for research and development in pulsed power technology.

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WEPMF075

Performance Measurements and Analysis of Jitter Like Events for the PS Injection Kicker System

controls, operation, injection, simulation

2549

A. Ferrero Colomo, J.C.C.M. Borburgh, L. Ducimetière, L.M.C. Feliciano, V. Forte, M.A. Fraser, T. Kramer, L. Sermeus
CERN, Geneva, Switzerland

In the framework of the LIU project, several modifications have been made to the CERN PS injection kicker system during the winter stop 2016-2017 (EYETS). Current waveform and beam-based measurements were carried out in 2017 to validate the implemented design changes by observing the magnetic field impact on the beam. During these long-term measurements, increased values for the rise and fall times were observed when compared to single shot observations of the current waveform. An unknown source of jitter-like pre-firing in the main switch has been identified, creating an additional challenge to meet the already tight system rise and fall time specifications. This paper briefly describes the efforts made to fine tune the pulse generator after the EYETS, summarises the optimised configuration and analyses the observed jitter events. A new triggering system design is briefly outlined to address the issue.

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WEPMF076

First Prototype Inductive Adder for the FCC Injection

injection, distributed, impedance, high-voltage

2553

D. Woog, M.J. Barnes, A. Ferrero Colomo, J. Holma, T. Kramer
CERN, Geneva, Switzerland

A highly reliable kicker system is required as part of the injection for the FCC. A significant weak point of conventional kicker systems is often the pulse generator, where a Pulse Forming Network/Line (PFN/PFL) is discharged through a thyratron switch to generate the current pulse for the kicker magnet. This design has several disadvantages: in particular the occasional erratic turn-on of the switch which cannot be accepted for the FCC. A potential replacement is the inductive adder (IA) that uses semiconductor switches and distributed capacitors as energy storage. The modular design, low maintenance and high flexibility make the IA a very interesting alternative. In addition, the ability to both turn-on and off the current also permits the replacement of PFN/PFL by the capacitors. A first FCC prototype IA, capable of generating 9 kV and 2.4 kA pulses, has been designed and built at CERN. It will be upgrade to a full-scale prototype (15 kV, 2.4 kA) in 2018. This paper presents measurement results from the 9 kV prototype and outlines the conceptual changes and expected performance of the 15 kV prototype.

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WEPMF077

Demonstration of Feasibility of the CLIC Damping Ring Extraction Kicker Modulators

flattop, extraction, damping, collider

2557

J. Holma, M.J. Barnes, A. Ferrero Colomo
CERN, Geneva, Switzerland

The CLIC study is investigating the technical feasibility of an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. Pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. The DR kicker systems must provide extremely stable field pulses to avoid beam emittance increase. The DR extraction kicker system consists of a stripline kicker and two pulse modulators. Specifications for the electromagnetic field pulses require that the modulator produce pulses of 160 or 900 ns flattop duration, ±12.5 kV and 305 A, with ripple and droop of not more than ±0.02 % (±2.5 V) with respect to an ideal waveform. Inductive adder topology has been chosen for the pulse modulators where the output waveform can be adjusted by applying analogue modulation methods. Two full-scale, 20-layer, 12.5 kV prototype inductive adders have been designed and built, and they are being tested at CERN. These modulators will be tested with a prototype stripline kicker, installed in a beamline at ALBA Synchrotron Light Source in Spain. The results of the laboratory tests and measurements are presented.

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WEPMF086

Eradication of Mercury Ignitron from the 400 kA Magnetic Horn Pulse Generator for CERN Antiproton Decelerator

proton, antiproton, target, operation

2586

V. Namora, M. Calviani, L. Ducimetière, P. Faure, L.E. Fernandez, G. Gräwer, V. Senaj
CERN, Geneva, Switzerland

The CERN Antiproton Decelerator (AD) produces low-energy antiprotons for studies of antimatter. A 26 GeV proton beam impacts the AD production target which produces secondary particles including antiprotons. A magnetic Horn (AD-Horn) in the AD target area is used to focus the diverging antiproton beam and increase the antiproton yield enormously. The horn is pulsed with a current of 400 kA, generated by capacitor discharge type generators equipped with ignitrons. These mercury-filled devices present a serious danger of environmental pollution in case of accident and safety constraints. An alternative has been developed using solid-state switches and diodes. Similar technology was already implemented at CERN for ignitron eradication in the SPS Horizontal beam dump in the early 2000s. A project was launched to design and set up a full-scale test-bench, to install and test a dedicated solid-state solution. Following the positive results obtained from the test-bench, the replacement of ignitrons by solid-state devices in the operational AD-Horn facility is currently under preparation. This paper describes the test-bench design and results obtained for this very high current pulser.

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WEPMF089

Measurements of Electromagnetic Properties of Ferrites as a Function of Frequency and Temperature

impedance, injection, coupling, simulation

2592

A. Chmielinska, M.J. Barnes, F. Caspers, B.K. Popovic, C. Vollinger
CERN, Geneva, Switzerland

Fast kicker magnets are used to inject beam into and extract beam out of the CERN accelerator rings. These kickers are often ferrite loaded transmission line type magnets with a rectangular shaped aperture through which the beam passes. The interaction of the beam with the resistive part of the longitudinal beam coupling impedance leads to power dissipation and heating of different elements in the accelerator ring. In particular, power deposition in the kicker magnets can be a limitation: if the temperature of the ferrite yoke exceeds the Curie temperature, the beam will not be properly deflected. In addition, the imaginary portion of the beam coupling impedance contributes to beam instabilities. A good knowledge of electromagnetic properties of materials up to GHz frequency range is essential for a correct impedance evaluation. This paper presents the results of transmission line measurements of complex initial permeability and permittivity for different ferrite types. We present an approach for deriving electromagnetic properties as a function of both frequency and temperature; this information is required for simulating ferrite behaviour under realistic operating conditions.

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WEPMG004

Design of the Future High Energy Beam Dump for the CERN SPS

operation, shielding, dumping, simulation

2612

S. Pianese, J.A. Briz Monago, M. Calviani, D. Grenier, P.B. Heckmann, J. Humbert, R. Illan Fiastre, A. Perillo-Marcone, G. Romagnoli, S. Sgobba, D. Steyart, V. Vlachoudis
CERN, Geneva, Switzerland

The future CERN Super Proton Synchrotron (SPS) internal dump (Target Internal Dump Vertical Graphite, known as TIDVG#5), to be installed during CERN's Long Shutdown 2 (2019-2020), will be required to intercept beam dumps from 26 to 450 GeV, with increased intensity and repetition rates with respect to its predecessor (TIDVG#4). The beam power to be managed by the dump will increase by approximately a factor of four; resulting in new challenges in terms of design in order to fulfil the highly demanding specification, which is based on guaranteeing a good performance of the machine with little or no limitations imposed by this device. This paper presents the proposed design, including material selection, manufacturing techniques and thermo-mechanical simulations under different operational scenarios expected during the lifetime of the device.

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WEPMK001

Preliminary Design of a Cooling System for the LHC Injection Kicker Magnets

injection, vacuum, operation, impedance

2624

L. Vega Cid, M.J. Barnes, L. Ducimetière, M.T. Moester, V. Vlachodimitropoulos, W.J.M. Weterings
CERN, Geneva, Switzerland
A. Abánades
ETSII UPM, Madrid, Spain

The CERN Large Hadron Collider (LHC) is equipped with two fast pulsed magnet systems (MKIs) that inject particle beams from the injector chain. Future operation for High Luminosity LHC (HL-LHC) with high intensity beams will cause heating of the ferrite yokes of the MKIs beyond their Curie temperature, preventing injection until the yokes cool down. Beam coupling impedance studies show that it is possible to move a substantial portion of the beam induced power deposition from the upstream ferrite yokes, which are the yokes with the highest power deposition, to ferrite rings located at the upstream end of the magnet. Thermal predictions show that this power redistribution, combined with the installation of a cooling system around the rings, will maintain the temperatures of all the yokes and ferrite rings below their Curie point. Since the rings are not pulsed to high voltage, whereas the ferrite yokes are, the installation of a cooling system is feasible around the rings. The proposed design of the cooling system will be tested to ensure good performance before its installation on the MKIs. The details of the simulations and the design process are reported.

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WEPMK002

Longitudinal Impedance Analysis of an Upgraded LHC Injection Kicker Magnet

impedance, simulation, injection, vacuum

2628

V. Vlachodimitropoulos, M.J. Barnes, L. Vega Cid, W.J.M. Weterings
CERN, Geneva, Switzerland

Prior to Long Shutdown 1 (LS1) one of the LHC injection kickers (MKIs) occasionally exhibited high temperatures leading to significant turnaround times. After a successful impedance mitigation campaign during LS1, the MKI ferrite yokes have remained below their Curie point and have not limited LHC's availability. However, for HL-LHC operation the MKI yokes are expected to exceed their Curie temperatures after long physics runs. To ensure uninterrupted future HL-LHC operation, a modified beam screen design, relocating some of the heat load to more easily cooled parts, and a suitable cooling system are under development as the current baseline for the HL-LHC upgrade of the MKIs. An upgraded beam screen providing such relocation has been designed, simulated and compared to the existing model. To validate simulations, two longitudinal beam coupling impedance measurement techniques have been used and the results are compared to predictions. The modified beam screen was implemented in an upgraded MKI installed in the LHC during the Year End Technical Stop (YETS) 2017/18.

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WEPMK003

An Upgraded LHC Injection Kicker Magnet

injection, vacuum, electron, impedance

2632

M.J. Barnes, C. Bracco, G. Bregliozzi, A. Chmielinska, L. Ducimetière, B. Goddard, T. Kramer, H. Neupert, L. Vega Cid, V. Vlachodimitropoulos, W.J.M. Weterings, C. Yin Vallgren
CERN, Geneva, Switzerland
A. Chmielinska
EPFL, Lausanne, Switzerland

Funding: Work supported by the HL-LHC project.
An upgrade of the LHC injection kickers is necessary for HL-LHC to avoid excessive beam induced heating of these magnets: the intensity of the HL-LHC beam will be twice that of LHC. In addition, in the event that it is necessary to exchange an injection kicker magnet, the newly installed kicker magnet would limit HL-LHC operation for a few hundred hours due to dynamic vacuum activity. Extensive studies have been carried out to identify practical solutions to these problems: these include redistributing a significant portion of the beam induced power deposition to ferrite parts of the kicker magnet which are not at pulsed high voltage and water cooling of these parts. Furthermore a surface coating, to mitigate dynamic vacuum activity, has been selected. The results of these studies, except for water cooling, have been implemented on an upgraded LHC injection kicker magnet: this magnet was installed in the LHC during the 2017-18 Year End Technical Stop. This paper presents the upgrades, including some test and measurement results.

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WEPMK005

Preliminary Results from Validation Measurements of the Longitudinal Power Deposition Model for the LHC Injection Kicker Magnet

impedance, injection, coupling, operation

2636

V. Vlachodimitropoulos, M.J. Barnes, A. Chmielinska
CERN, Geneva, Switzerland
A. Chmielinska
EPFL, Lausanne, Switzerland

During Run 1 of the LHC, one of the injection kicker magnets (MKIs) exhibited an excessively high ferrite temperature, caused by coupling of the high intensity beam to the real impedance of the magnet. Beam-screen upgrades, implemented during Long Shutdown 1 (LS1), have been very effective in reducing beam coupling impedance and since then the MKIs have not limited LHC's availability. However, temperature measurements during operation have shown that one end of the MKI's ferrite yoke is consistently hotter than the other. Detailed simulation models and data post-processing algorithms have been developed to understand and mitigate the observed behaviour. In the present paper, the model used to obtain the power loss distribution along the magnet is presented. The model is subsequently applied to two MKI design configurations under study: (i) the one currently in operation and (ii) an upgraded magnet that was installed in the LHC tunnel during the Year End Technical Stop (YETS) 2017/18. In order to validate the expected behaviour a novel measurement technique was developed, applied in both configurations and compared to predictions. The results obtained are reported and conclusions regarding the effectiveness of the design are drawn.

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WEPML021

First Performance Results of the PIP2IT MEBT 200 Ω Kicker Prototype

booster, impedance, ISOL, target

2724

G.W. Saewert, M.H. Awida, B.E. Chase, A.Z. Chen, J. Einstein-Curtis, D. Frolov, K.S. Martin, H. Pfeffer, D. Wolff
Fermilab, Batavia, Illinois, USA
S. Khole
BARC, Trombay, Mumbai, India
D. Sharma
RRCAT, Indore (M.P.), 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 PIP-II project is a program to upgrade the Fermilab accelerator complex. The PIP-II linac includes a 2.1 MeV Medium Energy Beam Transport (MEBT) section that incorporates a unique chopping system to perform arbi-trary, bunch-by-bunch removal of 162.5 MHz structured beam. The MEBT chopping system will consist of two identical kickers working together and a beam absorber. One design of two having been proposed has been a 200 Ω characteristic impedance traveling wave dual-helix kicker driven with custom designed high-speed switches. This paper reports on the first performance results of one prototype kicker built, installed and tested with beam at the PIP-II Injector Test (PIP2IT) facility. The helix deflector design details are discussed. The electrical performance of the high-speed switch driver operating at 500 V bias is presented. Tests performed were chopping beam at 81.25 MHz for microseconds as well as with a truly arbitrary pattern for 550 us bursts having a 45 MHz average switching rate and repeating at 20 Hz.

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WEPML029

Vacuum System of the HESR at FAIR, Status of Tests, Layout and Manufacturing

vacuum, dipole, injection, controls

2748

F.M. Esser, N.B. Bongers, J. Böker, P. Chaumet, R. Gebel, R. Greven, S. Hamzic, H. Jagdfeld, F. Klehr, B. Laatsch, G. Langenberg, D. Marschall, A. Mauel, G. Natour, D. Prasuhn, L. Reifferscheidt, M. Schmitt, L. Semke, R. Tölle
FZJ, Jülich, Germany

The Research Center Jülich is leading a consortium being responsible for the design and manufacturing of the High-Energy Storage Ring (HESR) which is part of the FAIR project in Darmstadt, Germany. The HESR is designed for antiprotons within a momentum range of 1.5-15 GeV/c but can also be used for heavy ion experiments. Therefore the vacuum quality is expected to be 10^-11 mbar or better which is a great challenge on the overall vacuum layout as well as on the surface quality of the chambers and beam tubes. Whereas all bent dipole chambers are installed, the manufacturing of the pumping bodies with integrated RF meshes as well as several diagnostic chambers are in the focus of investigation. To validate the intended pumping concept of both the bake-out arc sections and the non-bakable straight sections, final tests at the operational test benches are planned. In parallel, the purchasing of valves and first pumps will be prepared. The actual layout of the HESR vacuum system and its components will be presented as well as the progress of manufacturing of several vacuum chambers. The latest experimental test results will be presented also.

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WEPML069

Fast Kicker and Pulser R&D for the HEPS on-Axis Injection System

injection, impedance, vacuum, simulation

2846

H. Shi, J. Chen, Z. Duan, L. Huo, P. Liu, X.L. Shi, G. Wang, L. Wang, N. Wang
IHEP, Beijing, People's Republic of China

The HEPS plans to adopt on-axis injection scheme because the dynamic aperture of machine is not large enough for off-axis injection for its baseline 7BA lattice design. A sets of super fast kicker and pulser of ±15kV amplitude, 15ns pulse bottom width are needed for bunch spacing of 10ns to minimize perturbation on adjacent bunches. To achieve these requirement, a multifaceted R&D program including the strip-line kicker and HV pulser, was initiated last 2 years. So far, the prototype development of a 750mm long strip-line kicker and a DSRD pulser was completed and the preliminary test results show they can meet the baseline requirement of the HEPS.

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THXGBD4

Sirius Light Source Status Report

storage-ring, injection, booster, MMI

2886

A.R.D. Rodrigues, F.C. Arroyo, O.R. Bagnato, J.F. Citadini, R.H.A. Farias, J.G.R.S. Franco, R. Junqueira Leao, L. Liu, S.R. Marques, R.T. Neuenschwander, C. Rodrigues, F. Rodrigues, R.M. Seraphim, O.H.V. Silva
LNLS, Campinas, Brazil

Sirius is a Synchrotron Light Source Facility based on a 4th generation 3 GeV low emittance electron storage ring that is under construction in Campinas, Brazil. Presently the main tunnel for the accelerators is ready to start installations. The Linac tunnel was delivered earlier and the 150 MeV Linac from SINAP is almost ready to start commissioning early May. Commissioning of the storage ring is expected to start by the end of this year (2018). In this paper we briefly review the overall project parameters and design concepts and focus on highlights from the main subsystems.

Slides THXGBD4 [28.400 MB]

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THYGBF2

PIP-II Injector Test Warm Front End: Commissioning Update

rfq, operation, emittance, focusing

2943

L.R. Prost, R. Andrews, C.M. Baffes, J.-P. Carneiro, B.E. Chase, A.Z. Chen, E. Cullerton, P. Derwent, J.P. Edelen, J. Einstein-Curtis, D. Frolov, B.M. Hanna, D.W. Peterson, G.W. Saewert, A. Saini, V.E. Scarpine, A.V. Shemyakin, V.L. Sista, J. Steimel, D. Sun, A. Warner
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 Warm Front End (WFE) of the Proton Improvement Plan II Injector Test [1] at Fermilab has been constructed to its full length. It includes a 15-mA DC, 30-keV H⁻ ion source, a 2 m-long Low Energy Beam Transport (LEBT) with a switching dipole magnet, a 2.1 MeV CW RFQ, followed by a Medium Energy Beam Transport (MEBT) with various diagnostics and a dump. This report presents the commissioning status, focusing on beam measurements in the MEBT. In particular, a beam with the parameters required for injection into the Booster (5 mA, 0.55 ms macro-pulse at 20 Hz) was transported through the WFE.

Slides THYGBF2 [2.434 MB]

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THPAF006

Simulations of Cooling Rate and Diffusion for Coherent Electron Cooling Experiment

electron, FEL, simulation, bunching

2957

J. Ma, V. Litvinenko, G. Wang
BNL, Upton, Long Island, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA

Start-to-end numerical simulations have been performed using the code SPACE and GENESIS for the single pass of gold ions through the coherent electron cooling (CeC) device installed in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Cooling rate of CeC experiment has been predicted using off-reference energy ions in a finite Gaussian electron beam through a realistic beam-line, in which settings of quadrupoles and free-electron laser (FEL) device are relevant to BNL RHIC.

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THPAF084

Impact of RF Coupler Kicks on Beam Dynamics in BESSY VSR

cavity, simulation, SRF, lattice

3182

T. Mertens
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Berlin, Germany
T. Atkinson, F. Glöckner, A. Jankowiak, M. Ries, A.V. Tsakanian
HZB, Berlin, Germany

The expected BESSY II upgrade to BESSY VSR requires the installation of a superconducting RF system, consisting of four cavities. Two cavities will operate at 1.5 GHz and two at 1.75 GHz. Each of them is equipped with a Fundamental Power Coupler and with Higher Order Mode (HOM) damping waveguide couplers. Dedicated simulations of these cavities and couplers have shown that at the location of the FPC the beam will see a transverse kick [*], perturbing the closed orbit and affecting transverse beam dynamics. We present the results of simulations and experiments of the impact on transverse beam dynamics of these coupler induced kicks for different FPC orientations.
[*] Study on RF Coupler Kicks of SRF Cavities in the BESSY VSR Module
A. Tsakanian#, H.-W. Glock, T. Mertens, M. Ries, A. Velez, J. Knobloch
IPAC18

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THPAK002

Updated Model of the Resistive Wall Impedance for the Main Ring of J-PARC

impedance, space-charge, hadron, injection

3204

B. Yee-Rendón, Y.H. Chin, H. Kuboki, T. Toyama
KEK, Ibaraki, Japan
M. Schenk
CERN, Geneva, Switzerland

The resistive wall impedance is one of the major contributors of the impedance in the Main Ring of J-PARC. The present model assumes round chambers of stainless steel with perfect magnet boundary conditions for its surroundings. This work presents the model of the resistive wall impedances taking into account the different chamber geometries of Main Ring, the materials and more realistic surroundings. The models were benchmarked with measurements of the coherent tune shift of the Main Ring of J-PARC. The simulation of beam instabilities is a helpful tool to evaluate potential threats against the machine protection of the high intensity beams.

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THPAK015

Impedance and Heat Load Analysis of the Stripline Kicker in HEPS

impedance, simulation, coupling, injection

3234

N. Wang, J. Chen, Z. Duan, H. Shi, S.K. Tian, L. Wang, H.S. Xu
IHEP, Beijing, People's Republic of China

In the High Energy Photon Source (HEPS), strip-line kickers are adopted for beam injection and extraction. Beam coupling impedance contribution from the strip-line kicker is calculated. Detailed studies on the heat load dissipation have been performed. The peak electric field on the blade and the induced voltage on the feedthroughs due to the beam passage are also calculated.

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THPAK043

Performance Optimization of a Beam Dynamics PIC Code On Hybrid Computer Architectures

GPU, simulation, plasma, HOM

3309

Zh.C. Liu
IHEP, Beijing, People's Republic of China
J. Qiang
LBNL, Berkeley, California, USA

The self-consistent multi-particle tracking based on particle-in-cell method (PIC) has been widely used in particle accelerator beam dynamics study. However, the PIC simulation is time-consuming and needs to use modern parallel computers for high resolution applications. In this paper, we implemented and optimized a parallel beam dynamics PIC code on two types of hybrid parallel computer architectures: one is the GPU and GPU cluster, while the other is the "Knight Landing" CPU cluster.

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THPAK055

Suppression of Transverse Beam Instabilities by Stripline Kickers at TPS

impedance, feedback, damping, storage-ring

3346

P.J. Chou, C.K. Chan, C.-C. Chang, K.T. Hsu, K.H. Hu, C.K. Kuan, I.C. Sheng, F.H. Tseng
NSRRC, Hsinchu, Taiwan

Collective beam instabilities could limit the accelerator performance if proper countermeasures are not in place. Active beam feedback systems are commonly used to suppress beam instabilities. The resistive wall impedance including phase-II insertion devices at TPS are calculated with analytical formulas. The growth rate of transverse coupled bunch instabilities due to wall impedance is estimated by theory. The RF properties of existing stripline kickers in TPS are analyzed with a 3-D electromagnetic simulation code GdfidL. Based on the above analysis, the requirements for a beam feedback system are calculated and the results are reported.

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THPAK057

Simulations of Optical Stochastic Cooling with ELEGANT

damping, undulator, pick-up, radiation

3354

M.B. Andorf, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
V.A. Lebedev, V.A. Lebedev, P. Piot
Fermilab, Batavia, Illinois, USA

Fermilab is pursuing a proof-of-principle test of the Optical Stochastic Cooling (OSC) of 100 MeV electrons in the Integrable Optics Test Accelerator. In support of this we present simulations of horizontal damping with OSC. We find excellent agreement with theory on the amplitude dependent damping rates. Additionally particle tracking is used to confirm the necessity and effectiveness of sextupoles used to correct non-linear path lengthening in the OSC chicane.

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THPAK067

Progress Toward a Self-Consistent Beam at the Spallation Neutron Source

injection, solenoid, simulation, quadrupole

3382

J.A. Holmes, S.M. Cousineau, T.V. Gorlov, M.A. Plum
ORNL, Oak Ridge, Tennessee, USA
N.J. Evans
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the US DOE. This research was supported by the DOE Office of Science, Accelerator and Detector Research Program.
We have proposed to inject a self-consistent "rotating" beam into the Spallation Neutron Source (SNS). Self-consistent beam distributions are defined to be ellipsoidal, or elliptical in 2D, distributions that have uniform density and that retain these properties under all linear transformations. We have made much progress since the original proposal. We have demonstrated computationally the feasibility of injecting a rotating beam under realistic physics assumptions. We have optimized the injection scheme with respect to beam loss and to minimum necessary hardware changes. We have also determined how existing SNS beam diagnostic equipment can be used to verify the self-consistency of the injected beam. This paper will report the details of this work as well as the status of plans to carry out the self-consistency experiments.

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THPAL028

Commissioning of the Bunch-by-Bunch Feedback System in the MAX IV 1.5 GeV Ring

feedback, cavity, storage-ring, synchrotron

3688

D. Olsson, Å. Andersson, F.J. Cullinan, P.F. Tavares
MAX IV Laboratory, Lund University, Lund, Sweden

The MAX IV 1.5 GeV ring is an electron storage ring for production of synchrotron light in the IR to soft X-ray spectral range. The ring will deliver light to its first users during 2018. Bunch-By-Bunch (BBB) feedback has been needed to suppress coupled-bunch mode instabilities (CBMIs), and the feedback has this far been provided in all three planes by a single stripline kicker. This is done by combining the horizontal and vertical baseband feedback signals with the longitudinal feedback signal that is upconverted to the 150 MHz - 250 MHz range. The combined signal is then fed to two stripline electrodes. The layout of the BBB feedback system in the MAX IV 1.5 GeV ring is presented in this paper. Results from instability studies are also discussed.

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THPAL082

Development of a New Modular Switch Using a Next-Generation Semiconductor

power-supply, pulsed-power, ISOL, timing

3841

T. Takayanagi, K. Horino, T. Ueno
JAEA/J-PARC, Tokai-mura, Japan

An ultra-high-speed short pulse switch for high power have been developed by using SIC - MOSFET which is one of next generation semiconductors. Semiconductor switches using SIC-MOSFETs are expected to replace the thyratron, and they are composed of circuits in which many semiconductor switches are multiplexed in series and parallel for high power. Semiconductor switches using SIC-MOSFETs are expected to replace the thyratron, and they are also designed by connecting many semiconductor switches in parallel-series. To realize a low switching noise, it is common to form a symmetrical circuit. However, as the number of parallel connections increases, the circuit length between input and output becomes longer, so the output waveform is distorted due to any timing jitter or level fluctuation. Therefore, we propose a radially symmetric type of a module switch which does not cause level fluctuation due to the timing jitter by equalizing the circuit length independently of the number of semiconductor switches. The design and preliminary test results of two types of switch circuits, radially symmetric type and line symmetric type are presented here.

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THPAL128

Autonomous Topography Detection and Traversal for an Inspection Robot Within the Beamline of Particle Accelerators

vacuum, experiment, FEL, heavy-ion

3943

N. Schweizer
Technische Universität Darmstadt (TU Darmstadt, RMR), Darmstadt, Germany
I. Pongrac
GSI, Darmstadt, Germany

Particle accelerators feature ultra-high vacuum pipe systems with unique topography, i.e. with a multitude of different vacuum chambers of varying dimensions and varying pipe apertures. In order to be able to examine the interior of the entire vacuum system, even those parts which are not accessible without disassembling large parts of the accelerator, a semi-autonomous robot is being developed which shall traverse and visually inspect the vacuum system of particle accelerators. We present a generic concept based on distance sensors for the inspection robot to detect steps between vacuum chambers and gaps in the beamline. Movement strategies to autonomously overcome these basic obstacles are introduced. For evaluation we use simulations of ideal environments with flat surfaces as well as realistic beam pipe environments of the SIS100 particle accelerator. Additionally, a prototype of our robot concept confirms the implementation of all maneuvers. Results show that obstacles of previously unknown dimensions can be detected and reliably traversed.

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THPMF002

Studies for Injection with a Pulsed Multipole Kicker at ALBA

injection, storage-ring, lattice, octupole

4030

G. Benedetti, U. Iriso, M. Pont, D. Ramos Santesmases
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
E. Ahmadi
ILSF, Tehran, Iran

Injection into the ALBA storage ring presently uses a conventional local injection bump with four dipole kickers. However, following the promising results of the first tests with single multipole kicker injection at other light sources, studies to implement this new injection scheme have been started for ALBA. Two possible designs for the kicker have been considered: a pure octupole and a non-linear magnet similar to the BESSY type. A comparison between the expected performances of the two kicker designs has been carried out in terms of injection efficiency and transparency for the users. This paper summarises the beam dynamics results from multi-particle tracking simulations and the proposed kicker magnet design.

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THPMF013

The Stripline Kicker Prototype for the CLIC Damping Rings at ALBA: Installation, Commissioning and Beam Characterisation

extraction, storage-ring, synchrotron, impedance

4062

M. Pont, N. Ayala, M. Carlà, T.F.G. Günzel, U. Iriso, Z. Martí, R. Monge, A. Olmos, F. Pérez, M. Quispe
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
M.J. Barnes, C. Belver-Aguilar, Y. Papaphilippou
CERN, Geneva, Switzerland

The extraction system for the CLIC Damping Rings has very tight specifications. Therefore a full characterisation of the behaviour of the stripline kicker under conditions as close as possible to the expected working conditions will be very valuable. To that end the CLIC stripline has been installed in the ALBA Synchrotron Light Source and has been characterised with beam. Prior to its installation, the effect of the stripline kicker on the machine impedance has been assessed. The installation has required the design of an absorber to screen the stripline from synchrotron radiation and additional BPMs have been installed for a better kick angle determination. The commissioning of the stripline with beam has been performed following closely beam parameters, pressure and temperature. The studies with beam include the determination of the longitudinal and transverse impedance of the kicker*, the field homogeneity when excited with a dc field and the field ripple when pulsed. This contribution reports on the first experience with the stripline kicker for the CLIC DR in the ALBA storage ring and presents the results of the initial beam characterisation.
* M. Carla et al., "Beam based impedance measurements of the CLIC stripline at ALBA", Proc. of IPAC'2017.

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THPMF030

VSR Injector Upgrade at BESSY II

booster, cavity, injection, storage-ring

4110

T. Atkinson, P. Goslawski, J.G. Hwang, M. Ries
HZB, Berlin, Germany
T. Flisgen, T. Mertens
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Berlin, Germany

BESSY VSR is a fully funded project at the Helmholtz-Zentrum in Berlin (HZB). The objective is to produce simultaneously both long and short pulses in the storage ring. The implications for the existing injector systems and the upgrade strategy are presented. Envisaged is a global upgrade which includes additional accelerating structures to reduce the bunch length in the booster, orbit measurements and implementing longitudinal feedback.

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THPMF035

Numerical Analysis of Excitation Property of Pulse Picking by Resonant Excitation at BESSY II

betatron, synchrotron, emittance, radiation

4131

J.G. Hwang, M. Koopmans, R. Müller, M. Ries, A. Schälicke
HZB, Berlin, Germany

The pulse picking by resonant excitation (PPRE) method is applied at BESSY II to provide pseudo single bunch operation by separating the radiation from one horizontally enlarged bunch from the light of the multi-bunch filling. The bunch is enlarged by an excitation with an external signal close to the tune resonance. The variation of the beam size depends strongly on the frequency and amplitude of the excitation signal. In this paper we show the properties of the PPRE bunch studied by analytical modeling and numerical calculations using Elegant. The simulation results are compared with beam size measurements using a new interferometry beam size monitor at BESSY II.

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THPMF036

Status of the Conceptual Design of ALS-U

lattice, emittance, vacuum, cavity

4134

C. Steier, A.P. Allézy, A. Anders, K.M. Baptiste, E.S. Buice, K. Chow, G.D. Cutler, S. De Santis, R.J. Donahue, D. Filippetto, J.P. Harkins, T. Hellert, M.J. Johnson, J.-Y. Jung, S.C. Leemann, D. Leitner, M. Leitner, T.H. Luo, H. Nishimura, T. Oliver, O. Omolayo, J.R. Osborn, G.C. Pappas, S. Persichelli, M. Placidi, G.J. Portmann, S. Reyes, D. Robin, F. Sannibale, C. Sun, C.A. Swenson, M. Venturini, S.P. Virostek, W.L. Waldron, E.J. Wallén
LBNL, Berkeley, California, USA

Funding: This work was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The ALS-U conceptual design promises to deliver diffraction limited performance in the soft x-ray range by lowering the horizontal emittance to about 70 pm rad resulting in two orders of brightness increase for soft x-rays compared to the current ALS. The design utilizes a nine bend achromat lattice, with reverse bending magnets and on-axis swap-out injection utilizing an accumulator ring. This paper shows some aspects of the completed conceptual design of the accelerator, as well as some results of the R&D program that has been ongoing for the last years.

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THPMF042

Beam Based Measurement of Injection Parameters at KEK-PF

injection, septum, beam-transport, storage-ring

4152

K. Hirano
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
K. Harada, N. Higashi, Y. Kobayashi, S. Nagahashi, T. Obina, R. Takai, H. Takaki, A. Ueda
KEK, Ibaraki, Japan

KEK-PF is a 2.5 GeV synchrotron radiation facility. In recent years, the injection efficiency using conventional pulsed septum and kicker magnets has decreased. The main cause of this problem seems to be the change of the injection parameters due to the accumulation of the errors including the effect of the earthquake on March 11, 2011. For the improvement of the injection efficiency, the precise and detailed parameters of the beam injection under present configuration are essential. In order to fix these parameters, we measure the response of the pulsed magnets by using injected and stored beams. In this presentation, we show the beam based measurement and the simulation results for the PF ring injection system.

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THPMF052

The Swap-Out Injection Scheme for the High Energy Photon Source

injection, booster, storage-ring, extraction

4178

Z. Duan, J. Chen, Y.Y. Guo, Y. Jiao, J.L. Li, Y.M. Peng, J.Q. Wang, N. Wang, G. Xu, H.S. Xu
IHEP, Beijing, People's Republic of China

Funding: Work supported by Natural Science Foundation of China (No.11605212).
The on-axis swap-out scheme is a promising injection scheme for di raction-limited storage rings, since it only re- quires a rather small dynamic aperture and thus potentially allows a higher brightness compared to traditional o -axis injection schemes. However, a full charge injector is neces- sary for this scheme and its design can be nontrivial, in par- ticular to satisfy the large single bunch charge requirements in special lling patterns for timing experiments. In the High Energy Photon Source, we propose using the booster also as a high energy accumulator ring to recapture the spent bunches extracted from the storage ring, so as to relax the challenges in generation and acceleration of bunches with a high charge, and as a cost-e ective solution compared to building a dedicated full energy accumulator ring. In this paper, the beam dynamics issues of this scheme will be presented, trade-o s between the storage ring and booster beam parameters and hardware specifications will also be discussed.

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THPMK069

Design of the Beam Switchyard of a Soft X-ray FEL User Facility in Shanghai

FEL, linac, undulator, dipole

4456

S. Chen, H.X. Deng, C. Feng, B. Liu, D. Wang, R. Wang
SINAP, Shanghai, People's Republic of China

A soft X-ray FEL user facility, which is based on the existing test facility located in the Zhangjiang Campus of SINAP, is under construction. Two undulator lines will be installed parallelly in the undulator hall and their electron beams are served by a 1.5 GeV linac. For simultaneous operation of the two undulator lines, a beam distribution system should be used to connect the linac and the undulator lines. In this paper, the physics design of this beam distribution system will be presented and also the beam dynamic issues will be discussed.

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THPML093

New Fast Kicker Results from the Muon g-2 E-989 Experiment at Fermilab

experiment, monitoring, simulation, MMI

4879

A.P. Schreckenberger
The University of Texas at Austin, Austin, Texas, USA
D. Barak, C.C. Jensen, G.E. Krafczyk, R.L. Madrak, H. Nguyen, H. Pfeffer, M. Popovic, J.C. Stapleton, C. Stoughton
Fermilab, Batavia, Illinois, USA
A.T. Chapelain, A.A. Mikhailichenko, D. L. Rubin
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
N.S. Froemming
CENPA, Seattle, Washington, USA
J.L. Holzbauer
UMiss, University, Mississippi, USA
A.I. Keshavarzi
The University of Liverpool, Liverpool, United Kingdom

We describe the installation, commissioning, and characterization of the injection kicker system for the E-989 experiment at Fermilab for a precision measurement of the muon anomalous magnetic moment. Control and monitoring systems have been implemented to acquire and record the waveforms of each kicker pulse, and measurements of various kicker system observables were recorded in the presence of the 1.45 T g-2 storage ring magnetic field. These monitoring systems are necessary to understand the systematic contribution to the measurement of the precession frequency. We examine the dependence of muon capture to kicker field predictions.

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THPML095

Improvement of Wire-Stretching Technique to the RF Measurements of E-Center and Multipole Field for the Dipole Cavities

cavity, coupling, simulation, electron

4885

G.-T. Park, J. Guo, H. Wang
JLab, Newport News, Virginia, USA
A. Overstreet
ODU, Norfolk, Virginia, USA
B. P. Xiao, T. Xin
BNL, Upton, Long Island, New York, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
After the first publication* of wire-stretching technique from its principle to measure the electrical center of a deflecting cavity, more refinements of this techniques including the review of its analytical and simulation results, RF circuit improvement to improve the signal to noise ratio and its application to other cavities have been developed. These applications include the electrical center measurements for the LHC RFD and DQW crabbing cavity prototypes, multi-frequency harmonic kicker cavity for JLEIC electron cooler**, TE011 cavity developed for the beam magnetization measurement***, and a separator cavity at BNL****. Further development of measurement calibration, error reduction, alignment of cavity installation to the machine beam line, and multipole field analysis for the beam dynamics will be presented.
*H. Wang, Proceedings of NAPAC2016, pp225-228
**S. A. Overstreet, BS Thesis 2017, Guilford College, Greensboro, NC
***J. Guo et al. these proceedings
****T. Xin et al, these proceedings

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THPML116

AutoTuner: A General Graphical User Interface for Automated Tuning

GUI, interface, controls, target

4939

X. Huang
SLAC, Menlo Park, California, USA
T. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

AutoTuner is a general graphical user interface (GUI) that we developed for automated tuning or online optimization. The GUI provides a convenient interface to select tuning knobs, objectives, and optimization algorithms and to change the tuning control parameters. Tuning setup can be created and saved for reuse. The progress of the tuning processing is plotted in real time. The tuning process can be paused, aborted, or resumed. We have tested the program for real-life accelerator tuning problems.

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THPML138

Efficiency and Error Analysis of the HALS Injection Scheme

injection, simulation, lattice, storage-ring

5008

Z.B. Sun, G. Liu, W. Liu, F.L. Shang, L. Shang, W.B. Song
USTC/NSRL, Hefei, Anhui, People's Republic of China

Hefei Advanced Light Source (HALS) is a newly designed diffraction-limited storage ring.. The latest version of HALS has a 7BA lattice. One of the most important parts about HALS design is its injection system. Since conventional injection scheme is not suitable for DLSRs, many new injection schemes are proposed, including longitudinal injection scheme. In this paper, we investigate the feasibility of longitudinal injection scheme for HALS. In order to evaluate the injection performance, various errors have been considered. A series of tracking simulations are carried out and injection efficiency is obtained under different error levels.

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FRXGBD1

Reliability and Availability of Particle Accelerators: Concepts, Lessons, Strategy

operation, luminosity, collider, beam-losses

5014

A. Apollonio, L. Ponce, O. Rey Orozko, R. Schmidt, A.P. Siemko, B. Todd, J.A. Uythoven, A.P. Verweij, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland

This paper will present the results and latest status of an extensive effort to analyse and improve the reliability and availability of the LHC. After the introduction of basic concepts and definitions, the paper reviews the performance of the LHC in 2015-2017. A direct comparison of the luminosity production years 2016 and 2017 is presented, with a focus on the main differences in the observed failure modes. Based on the lessons learnt in this time window, expectations for the performance during future LHC runs are discussed. In particular, the thought process for the evaluation of the possible full energy exploitation of the LHC is described, considering relevant factors such as the expected availability loss and the risk associated to magnet training.

Slides FRXGBD1 [7.090 MB]

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FRXGBD2

Fast Kicker for High Current Beam Manipulation: Experimental Facility

experiment, simulation, septum, electron

5019

V.V. Gambaryan, A.A. Starostenko
BINP SB RAS, Novosibirsk, Russia
A.A. Starostenko
NSU, Novosibirsk, Russia

The pulsed deflecting magnet (kicker) project was worked out in Budker Institute of Nuclear Physics. The kicker design parameters are: impulsive force, 1 mT*m; pulse edge, 5 ns; impulse duration, 200 ns. The unconventional approach is that the plates must be replaced by a set of cylinders. The obtained magnet construction enables the field homogeneity to be controlled by changing current magnitudes in cylinders. Furthermore, we demonstrated the method of field optimization. In addition, measurement technique for the harmonic components was considered and the possibility of control harmonic components value was demonstrated. The results with electron beam on actual facility was considered.

Slides FRXGBD2 [4.864 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-FRXGBD2

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