IPAC2018 - List of Keywords (septum)

Paper	Title	Other Keywords	Page
TUPAF037	Validation of the CERN PS Eddy Current Injection Septa	simulation, vacuum, injection, HOM	768
	M. Hourican, B. Balhan, J.C.C.M. Borburgh, T. Masson, A. Sanz Ull CERN, Geneva, Switzerland
	As part of the upgrade of the CERN PS accelerator from 1.4 GeV to 2 GeV, new injection septa have been developed. The system is comprised of a pulsed eddy current septum magnet and a pulsed eddy current bumper magnet. Both magnets will be housed in a common vacuum vessel and powered by independent power converters. In-depth studies and simulations have been performed to reduce as much as possible the leak field by designing specific magnetic shielding, combined with dual function beam impedance shielding. A prototype magnet was built and measured to validate the simulations. The final complete system will be bake-able at 200C and uses demineralised water for cooling. Closed circuit cooling systems have been integrated to reduce risks of vacuum leaks. This report describes the electromechanical design from the concept and simulation stages to the prototyping and final manufacturing. Results of the initial magnetic measurements, including field homogeneity and leak field mitigation methods are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF037
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TUPAF052	Effects of Electrostatic Septum Alignment on Particle Loss During Slow Extraction at CERN SPS	alignment, extraction, simulation, operation	826
	J. Prieto, Y. Dutheil, M.A. Fraser, B. Goddard, V. Kain, L.S. Stoel, F.M. Velotti CERN, Geneva, Switzerland M.A. Kagan SLAC, Menlo Park, California, USA
	Slow extraction is an intrinsically lossy process that splits the beam with an electrostatic septum (ES), employing a thin-wire array to delimit the high electric field region that deflects the beam into the extraction channel. At CERN's Super Proton Synchrotron (SPS) the ES is over 16 m long and composed of 5 separate units containing separate wire-arrays that can be moved independently. The tanks are all mounted on a single support structure that can move the ensemble coherently. As a result, the large number of positional degrees of freedom complicates the alignment procedure in operation. Obtaining and maintaining accurate alignment of the ES with the beam is therefore crucial for minimising beam loss. In this paper, we investigate the alignment procedure for different operational scenarios using particle tracking simulations to understand the beam loss along the extraction straight as a function of the relative positions of each of the 5 separate ES units. An important aspect of the study was to understand the required alignment tolerance to achieve optimum extraction efficiency for a given configuration of wire-array thicknesses.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF052
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TUPAF053	Optimization of Diffuser (Pre-Scatterer) Configurations for Slow Extraction Loss Reduction at Electrostatic Septa	scattering, extraction, simulation, proton	830
	B. Goddard, B. Balhan, J.C.C.M. Borburgh, M.A. Fraser, L.O. Jorat, V. Kain, C. Lolliot, L.S. Stoel, P. Van Trappen, F.M. Velotti CERN, Geneva, Switzerland D. Barna Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary V.P. Nagaslaev Fermilab, Batavia, Illinois, USA
	Uncontrolled beam loss at the electrostatic septum is a performance limit for several existing or planned high power hadron accelerators delivering slow-extracted spills to fixed targets. A passive diffuser, or pre-scatterer, in a suitable configuration has been shown to reduce such beamloss significantly, with the actual gain factor depending on the parameters and details of the extraction process and hardware. In this paper, the optimization of diffuser configurations is investigated for a range of beam energies and extraction conditions, and the sensitivity to the available parameters explored via simulation results. The advantages and limitations of the diffuser are discussed and conclusions drawn concerning the specific case studies of the 8 GeV Fermilab debuncher ring and 400 GeV CERN SPS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF053
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TUPAF054	Slow Extraction Efficiency Measurements at the CERN SPS	extraction, proton, operation, simulation	834
	M.A. Fraser, K. Cornelis, L.S. Esposito, B. Goddard, V. Kain, F. Roncarolo, L.S. Stoel, F.M. Velotti CERN, Geneva, Switzerland
	The high efficiency of most slow extraction systems makes quantifying the exact amount of beam lost in the process extremely challenging. This is compounded by the lack of time structure in the extracted beam, as is typically required by the high-energy physics experiments, and the difficulty in accurately calibrating D.C. intensity monitors in the extraction line at count rates of ~ 10¹³ Hz. As a result, it is common for the extraction inefficiency to be measured by calibrating the beam loss signal induced by the slow extraction process itself. In this paper, measurements of the extraction efficiency performed at the CERN Super Proton Synchrotron for the third-integer resonant slow extraction of 400 GeV protons over recent years will be presented and compared to expectation from simulation. The technique employed will be discussed along with its limitations and an outlook towards a future online extraction efficiency monitoring system will be given.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF054
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TUPAF055	Progress Toward a Dynamic Extraction Bump for Slow Extraction in the CERN SPS	extraction, simulation, alignment, closed-orbit	838
	L.S. Stoel, M. Benedikt, M.A. Fraser, B. Goddard, J. Prieto, F.M. Velotti CERN, Geneva, Switzerland
	The possibility of reducing the angular spread of slow extracted particles with a time-dependent extraction bump at the CERN Super Proton Synchrotron (SPS) is under investigation. In order to create this so-called dynamic bump, two orthogonal knobs were designed to enable independent movements of the beam in position and angle at the upstream end of the electrostatic extraction septum (ES). With the present slow extraction scheme, simulations show that the use of a dynamic bump can reduce the angular spread at the ES by roughly a factor two and reduce beam loss on the ES. A reduction in the angular spread is also a prerequisite to exploit the full potential of other loss reduction techniques being considered for implementation at the SPS, like the active or passive diffusers planned for installation upstream of the ES in 2018. In this paper, the simulated loss reduction with a dynamic bump alone or in combination with other loss reduction techniques will be assessed, the first beam-based tests of the dynamic bump presented, the details of its implementation examined and its potential for future operation at the SPS discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF055
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TUPAF058	Optimization of the FCC-hh Beam Extraction System Regarding Failure Avoidance and Mitigation	extraction, kicker, hardware, collider	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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TUPAF060	Injection and Dump Systems for a 13.5 TeV Hadron Synchrotron HE-LHC	kicker, injection, extraction, 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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TUPAF061	Use of a Massless Septum to Increase Slow-Extraction Efficiency	extraction, sextupole, simulation, resonance	862
	K. Brunner, M.A. Fraser, B. Goddard, L.S. Stoel, C. Wiesner CERN, Geneva, Switzerland D. Barna Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary
	The Super Proton Synchrotron (SPS) at CERN provides slow-extracted beam for Fixed Target experiments in the North Area. For the higher extracted beam intensities requested by future experimental proposals, beam-loss induced activation will be one of the limiting factors for the availability of such a facility. In this paper, we present and discuss the concept of using a massless septum magnet to increase the extraction efficiency and decrease losses caused by protons scattering on the electrostatic-septa wires.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF061
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TUPAK010	The Development of a New Low Field Septum Magnet System for Fast Extraction in Main Ring of J-PARC	power-supply, operation, controls, feedback	981
	T. Shibata, K. Ishii, H. Matsumoto, T. Sugimoto KEK, Ibaraki, Japan K. Fan HUST, Wuhan, People's Republic of China
	The J-PARC Main Ring (MR) is being upgraded to improve its beam power to the design goal of 750 kW. One important way is to reduce the repetition period from 2.48 s to 1.3 s so that the beam power can be nearly doubled. We need to improve the septum magnets for fast extraction. We are improving the magnets and their power supplies. The present magnets which are conventional type have problem in durability of septum coil by its vibration, and large leakage field at the flange of the beam duct. The new magnets are eddy current type. The eddy current type does not have septum coil, but has a thin plate. We expect that there is no problem in durability, we can construct the thin septum plate, the leakage field can be reduced. The output of the present power supply are pattern current which of flat top is 10 ms width, the new one is short pulse which of one is 10 us. The short pulse consists of 1st and 3rd higher harmonic. We can expect that the flatness and reproducibility of flat top current can be improved. The calorific power can be also reduced. This paper will report the performance of the power supply and its magnetic field with the eddy septum magnet systems.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAK010
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TUPAK013	Geant4 Simulation of Radiation Effect on the Deflector of Extraction System in HUST SCC250	proton, neutron, radiation, simulation	990
	S. Hu, K. Fan, L.X.F. Li, Z.Y. Mei, Z.J. Zeng, L.G. Zhang HUST, Wuhan, People's Republic of China
	China has payed extensive attention to the development of proton therapy in recent years. When design a compact, high energy superconducting cyclotron for proton therapy， radiation effect induced by beam losses is a crucial consideration. Since the proton beam is extracted out of HUST SCC250 by electrostatic deflectors, the fierce interaction between proton beam and the deflector septum is the main cause of beam losses, which will bring about radiation effect leading to activation and coil quench. This paper presents simulation results of radiation effect by utilizing Geant4 Monte Carlo code. The energy depositions of proton beam in various septum materials are compared. Meanwhile, the yields, the ener-gy and angular distributions of secondary particles are investigated. Those simulation results based on radiation effect will provide us with valuable implications for the design of this superconducting cyclotron.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAK013
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TUPMF014	Synchrotron Accumulation on Off-Energy Closed-Orbit with Anti-Septum or Nonlinear Kicker	kicker, injection, 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, kicker, 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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TUPMF084	Optimization of the Injection Kicker Bump Leakage at PETRA III	kicker, injection, 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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WEXGBE1	Review of Top-up Injection Schemes for Electron Storage Rings	injection, kicker, synchrotron, 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]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEXGBE1
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WEPAL063	A Method to Tune Pulse Magnets' Waveforms	injection, kicker, power-supply, GUI	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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WEPMF017	Options for the Spectrometer Magnet of the eRHIC IR	dipole, hadron, shielding, detector	2401
	H. Witte, R.B. Palmer, B. Parker 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. Presently the electron-ion collider eRHIC is under design, which aims to provide a facility with a peak luminosity of 10³⁴cm^-2sec^-1. This paper outlines different concepts for the so-called B0 magnet, which is the first bending magnet after the interaction region. The B0 magnet has to provide a 1.3 T dipole field to the hadron beam, while the nearby electron beam should not be exposed to any field. Several possible solutions have been evaluated, each with their specific strengths and shortcomings. This paper presents an overview of the solutions.
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WEPMF082	Design and Construction of the CERN PS Booster Charge Exchange Injection Chicane Bumpers	injection, vacuum, simulation, linac	2575
	B. Balhan, C. Baud, J.C.C.M. Borburgh, M. Hourican CERN, Geneva, Switzerland
	In the framework of the LIU project and the connection from LINAC4 to PS Booster, the 160 MeV H⁻ beam will be injected horizontally into the PSB by means of one charge-exchange injection system for each PSB ring. A set of four outside vacuum pulsed dipole magnets (BSW) creating the required injection bump has been designed and built. The dynamic requirements for the bump ramp down determine, to a large extent, the field homogeneity due to the eddy currents induced in the corrugated Inconel vacuum chamber. Magnetic simulations were performed to determine the field harmonics during bump ramp down, and the results subsequently used for the dynamic tracking of the beam during injection. The mechanical design and construction of the magnets will be briefly outlined, and the article will conclude with the magnetic measurements of the magnets. The magnetic performance of the as built magnets will be compared with the simulations and the influence of the vacuum chambers on the magnetic field will be quantified.
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WEPMF083	Comparison of Superconducting Septa Topologies and Parameter Space Exploration	dipole, experiment, shielding, target	2578
	M.G. Atanasov, J.C.C.M. Borburgh, M. Hourican, A. Sanz Ull CERN, Geneva, Switzerland
	The unprecedented energy scale of the FCC poses challenging requirements for its magnetic elements including the septum magnets for injection and extraction. With an ambitious target field of 4 T and an apparent septum thickness of only 25 mm, different superconducting septa topologies have been investigated to explore their limitations. This article will cover the currently feasible topologies, amongst which the truncated cosine-theta, the double truncated cosine-theta, the superconducting shield (SuShi) and the so called stealth dipole. A performance figure of merit will be proposed, taking into account the maximum achievable magnetic field, the septum thickness and the leak field magnitude.
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WEPML036	Truncated Cosine Theta Magnet and the Applications	extraction, injection, collider, heavy-ion	2772
	K. Sugita, E.S. Fischer, P.J. Spiller GSI, Darmstadt, Germany
	Typically septum magnets are designed with a combination of a C-shape iron yoke and a copper cable. Due to leakage of a magnetic field at a circulating beam passing through a saturated iron area, high field septum magnets with this concept is not feasible. Thus, this conventional design approach is limited magnetic field strength below 2 Tesla. For high energy machines, like SIS300 at FAIR or FCC at CERN, high field septum magnets are required to shorten the injection and extraction branch lines. Recently superconducting magnets, which enable to reduce the size of a building, are being introduced to medical accelerators. However, even if bending magnets are replaced by high field magnets, long straight sections, which is partly composed by a conventional septum magnet, remain. By introducing high field septum magnets, more compact accelerator can be designed. To get over the limitation of 2 Tesla, a novel concept of a septum magnet generating high magnetic field has been developed and design studies are ongoing. By using superconducting technology, a septum magnet can be designed to generate more than 2 Tesla. We present the concept and various application for the accelerators.
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THPAK023	Proposal for Using DAΦNE as Pulse Stretcher for the Linac Positron Beam	extraction, linac, positron, pulse-stretcher	3258
	S. Guiducci, D. Alesini, M.E. Biagini, S. Bilanishvili, O.R. Blanco-García, M. Boscolo, B. Buonomo, S. Cantarella, D.G.C. Di Giulio, L.G. Foggetta, A. Gallo, A. Ghigo, L. Kankadze, C. Milardi, R. Ricci, U. Rotundo, L. Sabbatini, M. Serio, A. Stella INFN/LNF, Frascati (Roma), Italy P. Valente INFN-Roma, Roma, Italy
	The PADME experiment* proposes a search for the dark photon (A') in the e⁺e⁻ -> gamma A' process in a positron-on-target experiment, exploiting the positron beam of the DAΦNE linac at the Frascati National Laboratory. The linac could provide a number of positrons as high as 10⁹/pulse in a 200 ns pulse but the number of positrons for PADME is limited below 10⁵/pulse in order to keep the pile-up probability in the calorimeter low enough. The PADME experiment is indeed limited by the low duty factor (10e-5=200ns/20ms). An alternative proposal to use the DAΦNE positron ring as a linac pulse stretcher, by injecting each pulse into the ring and extracting it by a slow resonant extraction using the m/3 resonance, is described in this paper. This allows to distribute the positrons of a linac pulse in a much longer pulse (0.2 - 0.5 ms) increasing the duty factor up to ~ 2%. The required modifications of the DAΦNE positron transfer line and main ring are presented. A dedicate lattice for the ring has been designed and tracking of the positrons in the ring has been performed to optimize extraction parameters and give a preliminary estimate of the extracted beam characteristics. * M. Raggi et al., EPJ Web Conf. 96 (2015) 01025
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THPAL078	In-Vacuum Lambertson Septum for SPEAR3 Low Emittance Injection	simulation, vacuum, storage-ring, injection	3831
	M.A.G. Johansson, J. Langton, J.A. Safranek SLAC, Menlo Park, California, USA S.C. Gottschalk STI Magnetics LLC, Woodinville, USA
	Funding: Work supported by DOE Contract No. DE-AC02-76SF00515 A new in-vacuum Lambertson septum magnet is being designed for the SPEAR3 storage ring, intended to replace the existing septum to allow injection into a new lower emittance operation mode for SPEAR3. The new septum design is constrained to fit in the same length and have the same bend angle as the existing injection septum, so as to minimize changes to surrounding storage ring and transfer line components, while also meeting stringent requirements on the stored beam leakage field. This has led to a design using Vanadium Permendur alloy for the septum pole pieces, with shaping of the inner profile of the stored beam channel to minimize the leakage fields indicated in 2D and 3D magnetic simulations.
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THPMF042	Beam Based Measurement of Injection Parameters at KEK-PF	injection, kicker, 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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THPMF043	Development and Present Status of Photon Factory Light Sources	injection, operation, vacuum, storage-ring	4155
	T. Honda, Y. Kobayashi, S. Nagahashi, R. Takai KEK, Ibaraki, Japan
	Photon Factory of KEK manages two light sources, Photon Factory storage ring (PF-ring) and Photon Factory Advanced Ring (PF-AR) with an energy of 2.5 GeV and 6.5 GeV, respectively. Although it is unfortunate that the operation time of the accelerators is decreasing recent years due to a budget shortage and some unavoidable reconstructions, we are continuing the operation with a low failure rate and constructing a new beamline based on a novel undulator. Preparing for the start of the physics run of Super KEKB Factory, a new full energy beam transport line from the injector LINAC to PF-AR was constructed. With an installation of pulsed quadrupole magnets for the LINAC, continuous top-up injection has been established simultaneously for the four storage rings of PF and Super KEKB, and the operation of them has become compatible. As a result of increasing the injection energy of PF-AR form 3 GeV to 6.5 GeV, the beam instability during the injection disappeared, and the stability and efficiency of the injection improved significantly.
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FRXGBD2	Fast Kicker for High Current Beam Manipulation: Experimental Facility	kicker, experiment, simulation, 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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TUPAF037

Validation of the CERN PS Eddy Current Injection Septa

simulation, vacuum, injection, HOM

768

M. Hourican, B. Balhan, J.C.C.M. Borburgh, T. Masson, A. Sanz Ull
CERN, Geneva, Switzerland

As part of the upgrade of the CERN PS accelerator from 1.4 GeV to 2 GeV, new injection septa have been developed. The system is comprised of a pulsed eddy current septum magnet and a pulsed eddy current bumper magnet. Both magnets will be housed in a common vacuum vessel and powered by independent power converters. In-depth studies and simulations have been performed to reduce as much as possible the leak field by designing specific magnetic shielding, combined with dual function beam impedance shielding. A prototype magnet was built and measured to validate the simulations. The final complete system will be bake-able at 200C and uses demineralised water for cooling. Closed circuit cooling systems have been integrated to reduce risks of vacuum leaks. This report describes the electromechanical design from the concept and simulation stages to the prototyping and final manufacturing. Results of the initial magnetic measurements, including field homogeneity and leak field mitigation methods are presented.

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TUPAF052

Effects of Electrostatic Septum Alignment on Particle Loss During Slow Extraction at CERN SPS

alignment, extraction, simulation, operation

826

J. Prieto, Y. Dutheil, M.A. Fraser, B. Goddard, V. Kain, L.S. Stoel, F.M. Velotti
CERN, Geneva, Switzerland
M.A. Kagan
SLAC, Menlo Park, California, USA

Slow extraction is an intrinsically lossy process that splits the beam with an electrostatic septum (ES), employing a thin-wire array to delimit the high electric field region that deflects the beam into the extraction channel. At CERN's Super Proton Synchrotron (SPS) the ES is over 16 m long and composed of 5 separate units containing separate wire-arrays that can be moved independently. The tanks are all mounted on a single support structure that can move the ensemble coherently. As a result, the large number of positional degrees of freedom complicates the alignment procedure in operation. Obtaining and maintaining accurate alignment of the ES with the beam is therefore crucial for minimising beam loss. In this paper, we investigate the alignment procedure for different operational scenarios using particle tracking simulations to understand the beam loss along the extraction straight as a function of the relative positions of each of the 5 separate ES units. An important aspect of the study was to understand the required alignment tolerance to achieve optimum extraction efficiency for a given configuration of wire-array thicknesses.

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TUPAF053

Optimization of Diffuser (Pre-Scatterer) Configurations for Slow Extraction Loss Reduction at Electrostatic Septa

scattering, extraction, simulation, proton

830

B. Goddard, B. Balhan, J.C.C.M. Borburgh, M.A. Fraser, L.O. Jorat, V. Kain, C. Lolliot, L.S. Stoel, P. Van Trappen, F.M. Velotti
CERN, Geneva, Switzerland
D. Barna
Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary
V.P. Nagaslaev
Fermilab, Batavia, Illinois, USA

Uncontrolled beam loss at the electrostatic septum is a performance limit for several existing or planned high power hadron accelerators delivering slow-extracted spills to fixed targets. A passive diffuser, or pre-scatterer, in a suitable configuration has been shown to reduce such beamloss significantly, with the actual gain factor depending on the parameters and details of the extraction process and hardware. In this paper, the optimization of diffuser configurations is investigated for a range of beam energies and extraction conditions, and the sensitivity to the available parameters explored via simulation results. The advantages and limitations of the diffuser are discussed and conclusions drawn concerning the specific case studies of the 8 GeV Fermilab debuncher ring and 400 GeV CERN SPS.

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TUPAF054

Slow Extraction Efficiency Measurements at the CERN SPS

extraction, proton, operation, simulation

834

M.A. Fraser, K. Cornelis, L.S. Esposito, B. Goddard, V. Kain, F. Roncarolo, L.S. Stoel, F.M. Velotti
CERN, Geneva, Switzerland

The high efficiency of most slow extraction systems makes quantifying the exact amount of beam lost in the process extremely challenging. This is compounded by the lack of time structure in the extracted beam, as is typically required by the high-energy physics experiments, and the difficulty in accurately calibrating D.C. intensity monitors in the extraction line at count rates of ~ 10¹³ Hz. As a result, it is common for the extraction inefficiency to be measured by calibrating the beam loss signal induced by the slow extraction process itself. In this paper, measurements of the extraction efficiency performed at the CERN Super Proton Synchrotron for the third-integer resonant slow extraction of 400 GeV protons over recent years will be presented and compared to expectation from simulation. The technique employed will be discussed along with its limitations and an outlook towards a future online extraction efficiency monitoring system will be given.

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TUPAF055

Progress Toward a Dynamic Extraction Bump for Slow Extraction in the CERN SPS

extraction, simulation, alignment, closed-orbit

838

L.S. Stoel, M. Benedikt, M.A. Fraser, B. Goddard, J. Prieto, F.M. Velotti
CERN, Geneva, Switzerland

The possibility of reducing the angular spread of slow extracted particles with a time-dependent extraction bump at the CERN Super Proton Synchrotron (SPS) is under investigation. In order to create this so-called dynamic bump, two orthogonal knobs were designed to enable independent movements of the beam in position and angle at the upstream end of the electrostatic extraction septum (ES). With the present slow extraction scheme, simulations show that the use of a dynamic bump can reduce the angular spread at the ES by roughly a factor two and reduce beam loss on the ES. A reduction in the angular spread is also a prerequisite to exploit the full potential of other loss reduction techniques being considered for implementation at the SPS, like the active or passive diffusers planned for installation upstream of the ES in 2018. In this paper, the simulated loss reduction with a dynamic bump alone or in combination with other loss reduction techniques will be assessed, the first beam-based tests of the dynamic bump presented, the details of its implementation examined and its potential for future operation at the SPS discussed.

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TUPAF058

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

extraction, kicker, hardware, collider

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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TUPAF060

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

kicker, injection, extraction, 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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TUPAF061

Use of a Massless Septum to Increase Slow-Extraction Efficiency

extraction, sextupole, simulation, resonance

862

K. Brunner, M.A. Fraser, B. Goddard, L.S. Stoel, C. Wiesner
CERN, Geneva, Switzerland
D. Barna
Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary

The Super Proton Synchrotron (SPS) at CERN provides slow-extracted beam for Fixed Target experiments in the North Area. For the higher extracted beam intensities requested by future experimental proposals, beam-loss induced activation will be one of the limiting factors for the availability of such a facility. In this paper, we present and discuss the concept of using a massless septum magnet to increase the extraction efficiency and decrease losses caused by protons scattering on the electrostatic-septa wires.

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TUPAK010

The Development of a New Low Field Septum Magnet System for Fast Extraction in Main Ring of J-PARC

power-supply, operation, controls, feedback

981

T. Shibata, K. Ishii, H. Matsumoto, T. Sugimoto
KEK, Ibaraki, Japan
K. Fan
HUST, Wuhan, People's Republic of China

The J-PARC Main Ring (MR) is being upgraded to improve its beam power to the design goal of 750 kW. One important way is to reduce the repetition period from 2.48 s to 1.3 s so that the beam power can be nearly doubled. We need to improve the septum magnets for fast extraction. We are improving the magnets and their power supplies. The present magnets which are conventional type have problem in durability of septum coil by its vibration, and large leakage field at the flange of the beam duct. The new magnets are eddy current type. The eddy current type does not have septum coil, but has a thin plate. We expect that there is no problem in durability, we can construct the thin septum plate, the leakage field can be reduced. The output of the present power supply are pattern current which of flat top is 10 ms width, the new one is short pulse which of one is 10 us. The short pulse consists of 1st and 3rd higher harmonic. We can expect that the flatness and reproducibility of flat top current can be improved. The calorific power can be also reduced. This paper will report the performance of the power supply and its magnetic field with the eddy septum magnet systems.

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TUPAK013

Geant4 Simulation of Radiation Effect on the Deflector of Extraction System in HUST SCC250

proton, neutron, radiation, simulation

990

S. Hu, K. Fan, L.X.F. Li, Z.Y. Mei, Z.J. Zeng, L.G. Zhang
HUST, Wuhan, People's Republic of China

China has payed extensive attention to the development of proton therapy in recent years. When design a compact, high energy superconducting cyclotron for proton therapy， radiation effect induced by beam losses is a crucial consideration. Since the proton beam is extracted out of HUST SCC250 by electrostatic deflectors, the fierce interaction between proton beam and the deflector septum is the main cause of beam losses, which will bring about radiation effect leading to activation and coil quench. This paper presents simulation results of radiation effect by utilizing Geant4 Monte Carlo code. The energy depositions of proton beam in various septum materials are compared. Meanwhile, the yields, the ener-gy and angular distributions of secondary particles are investigated. Those simulation results based on radiation effect will provide us with valuable implications for the design of this superconducting cyclotron.

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TUPMF014

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

kicker, injection, 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, kicker, 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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TUPMF084

Optimization of the Injection Kicker Bump Leakage at PETRA III

kicker, injection, 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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WEXGBE1

Review of Top-up Injection Schemes for Electron Storage Rings

injection, kicker, synchrotron, 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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WEPAL063

A Method to Tune Pulse Magnets' Waveforms

injection, kicker, power-supply, GUI

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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WEPMF017

Options for the Spectrometer Magnet of the eRHIC IR

dipole, hadron, shielding, detector

2401

H. Witte, R.B. Palmer, B. Parker
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.
Presently the electron-ion collider eRHIC is under design, which aims to provide a facility with a peak luminosity of 10³⁴cm^-2sec^-1. This paper outlines different concepts for the so-called B0 magnet, which is the first bending magnet after the interaction region. The B0 magnet has to provide a 1.3 T dipole field to the hadron beam, while the nearby electron beam should not be exposed to any field. Several possible solutions have been evaluated, each with their specific strengths and shortcomings. This paper presents an overview of the solutions.

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WEPMF082

Design and Construction of the CERN PS Booster Charge Exchange Injection Chicane Bumpers

injection, vacuum, simulation, linac

2575

B. Balhan, C. Baud, J.C.C.M. Borburgh, M. Hourican
CERN, Geneva, Switzerland

In the framework of the LIU project and the connection from LINAC4 to PS Booster, the 160 MeV H⁻ beam will be injected horizontally into the PSB by means of one charge-exchange injection system for each PSB ring. A set of four outside vacuum pulsed dipole magnets (BSW) creating the required injection bump has been designed and built. The dynamic requirements for the bump ramp down determine, to a large extent, the field homogeneity due to the eddy currents induced in the corrugated Inconel vacuum chamber. Magnetic simulations were performed to determine the field harmonics during bump ramp down, and the results subsequently used for the dynamic tracking of the beam during injection. The mechanical design and construction of the magnets will be briefly outlined, and the article will conclude with the magnetic measurements of the magnets. The magnetic performance of the as built magnets will be compared with the simulations and the influence of the vacuum chambers on the magnetic field will be quantified.

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WEPMF083

Comparison of Superconducting Septa Topologies and Parameter Space Exploration

dipole, experiment, shielding, target

2578

M.G. Atanasov, J.C.C.M. Borburgh, M. Hourican, A. Sanz Ull
CERN, Geneva, Switzerland

The unprecedented energy scale of the FCC poses challenging requirements for its magnetic elements including the septum magnets for injection and extraction. With an ambitious target field of 4 T and an apparent septum thickness of only 25 mm, different superconducting septa topologies have been investigated to explore their limitations. This article will cover the currently feasible topologies, amongst which the truncated cosine-theta, the double truncated cosine-theta, the superconducting shield (SuShi) and the so called stealth dipole. A performance figure of merit will be proposed, taking into account the maximum achievable magnetic field, the septum thickness and the leak field magnitude.

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WEPML036

Truncated Cosine Theta Magnet and the Applications

extraction, injection, collider, heavy-ion

2772

K. Sugita, E.S. Fischer, P.J. Spiller
GSI, Darmstadt, Germany

Typically septum magnets are designed with a combination of a C-shape iron yoke and a copper cable. Due to leakage of a magnetic field at a circulating beam passing through a saturated iron area, high field septum magnets with this concept is not feasible. Thus, this conventional design approach is limited magnetic field strength below 2 Tesla. For high energy machines, like SIS300 at FAIR or FCC at CERN, high field septum magnets are required to shorten the injection and extraction branch lines. Recently superconducting magnets, which enable to reduce the size of a building, are being introduced to medical accelerators. However, even if bending magnets are replaced by high field magnets, long straight sections, which is partly composed by a conventional septum magnet, remain. By introducing high field septum magnets, more compact accelerator can be designed. To get over the limitation of 2 Tesla, a novel concept of a septum magnet generating high magnetic field has been developed and design studies are ongoing. By using superconducting technology, a septum magnet can be designed to generate more than 2 Tesla. We present the concept and various application for the accelerators.

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THPAK023

Proposal for Using DAΦNE as Pulse Stretcher for the Linac Positron Beam

extraction, linac, positron, pulse-stretcher

3258

S. Guiducci, D. Alesini, M.E. Biagini, S. Bilanishvili, O.R. Blanco-García, M. Boscolo, B. Buonomo, S. Cantarella, D.G.C. Di Giulio, L.G. Foggetta, A. Gallo, A. Ghigo, L. Kankadze, C. Milardi, R. Ricci, U. Rotundo, L. Sabbatini, M. Serio, A. Stella
INFN/LNF, Frascati (Roma), Italy
P. Valente
INFN-Roma, Roma, Italy

The PADME experiment* proposes a search for the dark photon (A') in the e⁺e⁻ -> gamma A' process in a positron-on-target experiment, exploiting the positron beam of the DAΦNE linac at the Frascati National Laboratory. The linac could provide a number of positrons as high as 10⁹/pulse in a 200 ns pulse but the number of positrons for PADME is limited below 10⁵/pulse in order to keep the pile-up probability in the calorimeter low enough. The PADME experiment is indeed limited by the low duty factor (10e-5=200ns/20ms). An alternative proposal to use the DAΦNE positron ring as a linac pulse stretcher, by injecting each pulse into the ring and extracting it by a slow resonant extraction using the m/3 resonance, is described in this paper. This allows to distribute the positrons of a linac pulse in a much longer pulse (0.2 - 0.5 ms) increasing the duty factor up to ~ 2%. The required modifications of the DAΦNE positron transfer line and main ring are presented. A dedicate lattice for the ring has been designed and tracking of the positrons in the ring has been performed to optimize extraction parameters and give a preliminary estimate of the extracted beam characteristics.
* M. Raggi et al., EPJ Web Conf. 96 (2015) 01025

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THPAL078

In-Vacuum Lambertson Septum for SPEAR3 Low Emittance Injection

simulation, vacuum, storage-ring, injection

3831

M.A.G. Johansson, J. Langton, J.A. Safranek
SLAC, Menlo Park, California, USA
S.C. Gottschalk
STI Magnetics LLC, Woodinville, USA

Funding: Work supported by DOE Contract No. DE-AC02-76SF00515
A new in-vacuum Lambertson septum magnet is being designed for the SPEAR3 storage ring, intended to replace the existing septum to allow injection into a new lower emittance operation mode for SPEAR3. The new septum design is constrained to fit in the same length and have the same bend angle as the existing injection septum, so as to minimize changes to surrounding storage ring and transfer line components, while also meeting stringent requirements on the stored beam leakage field. This has led to a design using Vanadium Permendur alloy for the septum pole pieces, with shaping of the inner profile of the stored beam channel to minimize the leakage fields indicated in 2D and 3D magnetic simulations.

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THPMF042

Beam Based Measurement of Injection Parameters at KEK-PF

injection, kicker, 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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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF042

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THPMF043

Development and Present Status of Photon Factory Light Sources

injection, operation, vacuum, storage-ring

4155

T. Honda, Y. Kobayashi, S. Nagahashi, R. Takai
KEK, Ibaraki, Japan

Photon Factory of KEK manages two light sources, Photon Factory storage ring (PF-ring) and Photon Factory Advanced Ring (PF-AR) with an energy of 2.5 GeV and 6.5 GeV, respectively. Although it is unfortunate that the operation time of the accelerators is decreasing recent years due to a budget shortage and some unavoidable reconstructions, we are continuing the operation with a low failure rate and constructing a new beamline based on a novel undulator. Preparing for the start of the physics run of Super KEKB Factory, a new full energy beam transport line from the injector LINAC to PF-AR was constructed. With an installation of pulsed quadrupole magnets for the LINAC, continuous top-up injection has been established simultaneously for the four storage rings of PF and Super KEKB, and the operation of them has become compatible. As a result of increasing the injection energy of PF-AR form 3 GeV to 6.5 GeV, the beam instability during the injection disappeared, and the stability and efficiency of the injection improved significantly.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF043

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FRXGBD2

Fast Kicker for High Current Beam Manipulation: Experimental Facility

kicker, experiment, simulation, 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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