Paper | Title | Other Keywords | Page |
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MOPGW002 | Longitudinal Kicker Design for Sirius Light Source | cavity, HOM, GUI, feedback | 57 |
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An overloaded cavity kicker for the Sirius longitudinal bunch-by-bunch feedback system will be presented in this contribution. 4th generation light sources’ lower aperture of vacuum chambers lead to higher cutoff frequencies, jeopardizing the electromagnetic performance of cavities by trapping higher order modes (HOMs) inside the structure. With the objective of damping longitudinal and transverse HOMs without compromising the kicker shunt impedance, solutions as cavity radius reduction, tapered transitions and other geometry changes are discussed herein. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW002 | ||
About • | paper received ※ 15 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019 | ||
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MOPGW008 | Transparent Injection for ESRF-EBS | injection, SRF, sextupole, power-supply | 78 |
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The commissioning of the ESRF-EBS storage ring will start in December 2019 ultimately providing a horizontal emittance of 130 pm, 30 times lower than the present one. Due to the reduced beam lifetime top-up operation will be required for all operating modes. Transparent injection, i.e. with negligible perturbations on the stored beam, is necessary to allow continuous data acquisition for beam lines experiments. Several options have been considered at ESRF to reduce these perturbations down to a fraction of the rms beam size: i) new kickers power supplies with slow ramping time to facilitate active compensation are under development and will be implemented in the coming years ii) in parallel, long term solutions using non-linear kickers and longitudinal on-axis injection have been investigated. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW008 | ||
About • | paper received ※ 13 May 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019 | ||
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MOPGW044 | Off-Energy Off-Axis Injection with Pulsed Multipole Magnet Into the HALS Storage Ring | injection, storage-ring, lattice, multipole | 187 |
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As a future Diffraction-Limited Storage Ring (DLSR) at NSRL, the Hefei Advanced Light Source (HALS) has been proposed and has a great progress in the lattice optimization. The nonlinear dynamics is well designed and shows good performance, which makes it easier for beam injection and gives us more choices to design a more suitable injection scheme. In this paper, a new off-energy off-axis pulsed multipole injection scheme is proposed. The off-energy beam is off-axis injected into the acceptance of the storage ring with one or several pulsed multipole kickers and meanwhile the stored beam is almost unaffected during the injection. The injection acceptance of the storage ring is analyzed and the injection scheme is preliminary designed. A series of tracking simulations are carried out and the results are presented. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW044 | ||
About • | paper received ※ 15 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019 | ||
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MOPGW074 | New Spiral Beam Screen Design for the FCC-hh Injection Kicker Magnet | impedance, injection, coupling, vacuum | 270 |
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The injection kicker system for the Future Circular Collider (FCC-hh) must satisfy demanding requirements. To achieve low pulse ripple and fast field rise and fall times, the injection system will use ferrite loaded transmission line type magnets. The beam coupling impedance of the kicker magnets is crucial, as this can be a dominant contribution to beam instabilities. In addition, interaction of the high intensity beam with the real part of the longitudinal beam coupling impedance can result in high power deposition in the ferrite yoke. This gives a significant risk that the ferrite yoke will exceed its Curie temperature: hence, a suitable beam screen will be a critical feature. In this paper, we present a novel concept - a spiral beam screen. The fundamental advantage of the new design is a significant reduction of the maximum voltage induced on the screen conductors, thus decreased probability of electrical breakdown. In addition, the longitudinal beam coupling impedance is optimized to minimize power deposition in the magnet. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW074 | ||
About • | paper received ※ 26 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | ||
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MOPRB036 | Study on Beam-induced heating in injection section of Hefei Light Source | impedance, vacuum, radiation, experiment | 652 |
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Ceramic chambers distributed with metal belts on the inner surface are installed in the injection section at Hefei Light Source (HLS). Heating on the ceramics chambers has been observed during machine operation. An air compressor is used to cool these chambers due to concerns of overheating during top-up operation mode. To understand the sources of the heating, a series of experiments are performed with various beam currents and bunch filling patterns. The study shows that the heating is mainly caused by the narrow-band impedances of the ceramic chambers and their adjacent vacuum components. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB036 | ||
About • | paper received ※ 22 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | ||
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MOPRB106 | 3D Theory of Microbunched Electron Cooling for Electron-Ion Colliders | electron, hadron, simulation, betatron | 814 |
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Funding: This work was supported by the Department of Energy, Contract No. DE-AC02-76SF00515. The Microbunched Electron Cooling (MBEC) * is a promising cooling technique that can find applications in future hadron and electron-ion colliders. A 1D model of MBEC has been recently developed in Ref. **. This model predicts the cooling time below two hours for eRHIC 255 GeV proton beams, when two amplification sections are used in the cooling system. In this work, we go beyond the 1D model of Ref. * and develop a realistic 3D theory of MBEC. Our approach is based on the analysis of the dynamics of microscopic 3D fluctuations in the electron and hadron beams during their interaction and propagation through the system. We derive an analytical expression for the cooling rate and optimize it for the parameters of eRHIC. Our analytical results are in reasonable agreement with simulations. * D. Ratner. Phys. Rev. Lett. 111, 084802 (2013). ** G. Stupakov. PRAB 21, 114402 (2018) |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB106 | ||
About • | paper received ※ 29 April 2019 paper accepted ※ 18 May 2019 issue date ※ 21 June 2019 | ||
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MOPTS030 | Characterisation and First Beam Line Tests of the Elbe Stripline Kicker | laser, septum, neutron, simulation | 918 |
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The linac based CW electron accelerator ELBE operates different secondary beamlines one at a time. For the future different end stations should be served simultaneously, hence specific bunch patterns have to be kicked into different beam-lines. The variability of the bunch pattern and the frequency resp. switching time are one of the main arguments for a stripline-kicker. A design with two tapered active electrodes and two ground fenders was optimized in time and frequency domain with the software package CST. From that a design has been transferred into a construction and was manufactured. The prototype has been tested in the laboratory and installed in the ELBE beam line. The presentation summarises the recent results and the first beam line test. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS030 | ||
About • | paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | ||
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MOPTS106 | Barrier Bucket Studies in the CERN PS | cavity, proton, LLRF, ISOL | 1128 |
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Part of the residual beam loss during the Multi-Turn Extraction (MTE) of fixed target beams from the CERN Proton Synchrotron (PS) can be attributed to kicker magnets switching while the beam is coasting with the main RF systems off before extraction. Generating a barrier bucket to deplete the longitudinal line density of the coasting beam during the kicker rise time can reduce these losses. Beam tests have been performed with an existing Finemet cavity in the PS, which is normally operated as a wideband feedback kicker. To drive the cavity, a beam synchronous waveform synthesizer based on programmable logic has been developed. It produces a pre-distorted signal which ideally results in a single period sinusoidal voltage pulse with programmable parameters at the gap of the cavity, once or multiple times per revolution. The modelling of the behavior of the power amplifier and the cavity is essential to achieve an anti-symmetric voltage pulse with little pre- and post-pulse ripple. The design of the beam-synchronous waveform generator is presented together with results from initial beam studies with the created barrier buckets in the PS. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS106 | ||
About • | paper received ※ 18 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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TUZZPLS2 | Beam Dynamics, Injection and Impedance Studies for the Proposed Single Pulsed Nonlinear Injection Kicker at the Australian Synchrotron | impedance, injection, synchrotron, storage-ring | 1219 |
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The Australian Synchrotron are currently investigating the use of a single pulsed nonlinear injection kicker (NLK) to free floor space within the ring for future beamline development. The NLK has a zero and flat magnetic field at the stored beam to leave the stored beam undisturbed but has a maximum field off-axis where the injected beam is located. After the kick, the injected beam is stored. While NLKs have been prototyped at many facilities around the world, injection efficiency and heat loading have been the main impediment to deployment of the NLK. The wakefields that pass through the ceramic chamber aperture can cause severe heat loading and impedance. Despite achieving impressive injection efficiencies, a previous prototype at BESSY II * showed that strong interactions of the stored beam resulted in high heat load causing the thin 5µm Titanium coated ceramic chamber to reach temperatures > 500 °C and fail. To avoid beam induced heat loads, this paper presents studies of the wake impedance and thermal behaviour for our proposed NLK design. Injection simulations and future considerations for installation and operation at the Australian Synchrotron will be discussed.
* T. Atkinson et al., "Development of a non-linear kicker system to facilitate a new injection scheme for the Bessy II storage ring", in Proc. IPAC’11, 2011, THPO024, pp. 3394-3396. |
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Slides TUZZPLS2 [1.588 MB] | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUZZPLS2 | ||
About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | ||
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TUPGW029 | The Injection System and the Injector Complex for PETRA IV | injection, emittance, gun, booster | 1465 |
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PETRA IV project is to upgrade PETRA III to a synchrotron radiation source with an ultra-low emittance. Due to the small dynamic aperture of the PETRA IV storage ring, a horizontal on-axis injection is prepared. In this paper, the preliminary study of the injection scheme is described. To meet the requirements of the on-axis injection, a plan of a new injector complex, including the Gun, the LINAC and the accumulator is shown in this paper. Several options are discussed in this paper, too. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW029 | ||
About • | paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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TUPGW048 | Simulation of Injection Efficiency for the High Energy Photon Source | injection, booster, storage-ring, extraction | 1514 |
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Funding: Work supported by Natural Science Foundation of China (No.11605212). A ’high-energy accumulation’ scheme [1] was proposed to deliver the full charge bunches for the swap-out injec- tion of the High Energy Photon Source. In this scheme, the depleted storage ring bunches are recovered via merging with small charge bunches in the booster, before being refilled into the storage ring. In particular, the high charge bunches are transferred twice between the storage ring and the booster, and thus it is essential to maintain a near per- fect transmission efficiency in the whole process. In this paper, major error effects affecting the transmission efficiency are analyzed and their tolerances are summarized, injection simulations indicate a satisfactory transmission efficiency is achievable for the present baseline lattice. * Z. Duan, et al., "The swap-out injection scheme for the High Energy Photon Source", Proc. IPAC’18, THPMF052 |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW048 | ||
About • | paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | ||
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TUPGW063 | Studying the Dynamic Influence on the Stored Beam From a Coating in a Multipole Injection Kicker | injection, emittance, operation, simulation | 1547 |
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The MAX IV 3 GeV ring is the first synchrotron light source utilizing the Multi-Bend Achromat scheme to achieve a low horizontal bare-lattice emittance of 328 pm rad providing high brilliance x-rays for users. A novel Multipole Injection Kicker (MIK) designed and constructed by SOLEIL is used to allow top-up operation with only minor disturbances to the stored beam, i.e., the users. We investigate the stored beam perturbations due to quadrupole fields arising during the MIK pulse, originating from its inner coating. Maximum bunch emittance growth of §I{21}{πco\meter\radian} was found in simulations. Measurements of the stored beam impact are performed and found to be in good agreement with simulations. We conclude that the MIK at MAX IV 3 GeV has the potential to deliver quasi-transparent injections with good capture efficiency. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW063 | ||
About • | paper received ※ 06 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019 | ||
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TUPRB081 | Beam Motion and Photon Flux Dips during Injection at the Taiwan Photon Source | injection, photon, betatron, vacuum | 1848 |
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The Taiwan photon source (TPS) is a 3 GeV synchrotron light source now in routine operation at the NSRRC. At the beginning of beam commissioning, significant photon flux dips could be observed at injection due to a blow-up of the beam size. To eliminate this transient effect, all four kickers were rematched. The leakage field was shielded and the induced current loops at vacuum chambers in the injection area were also eliminated. These efforts reduced the horizontal betatron oscillations and orbit distortions to around one-tenth. In order to decrease the recovery time of photon dips during injection, the operational chromaticity was reduced to improve incoherent effects. After all those improvements, the photon flux dips during injection dropped to 30 % and the recovery time to less than 1 msec. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB081 | ||
About • | paper received ※ 17 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | ||
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TUPTS034 | Development of Low Inductance Circuit for Radially Symmetric Circuit | experiment, impedance, high-voltage, operation | 2013 |
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Radiation symmetric type circuits using semiconductors of SIC-MOSFETs, one of next generation semiconductors, are composed of circuits in which many semiconductor switches are multiplexed in series and in parallel. Since the lengths of all parallel circuits are equal, the output waveform will not be distorted due to timing jitter or level change. This circuit is useful for outputting the waveform of ultrafast short pulse. Therefore, we have developed a circuit that achieves further low inductance by making the power transmission circuit into a double circular ring structure equal to the coaxial shape. Compare the inductance value obtained from the structure and the output waveform. In addition, we compare the calculation and the actual measurement in the actual test and present the verification result of the developed circular ring structure. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS034 | ||
About • | paper received ※ 01 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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TUPTS099 | Predicting the Performances of Coherent Electron Cooling with Plasma Cascade Amplifier | electron, plasma, space-charge, collider | 2150 |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Recently, we proposed a new type of instability, Plasma Cascade Instability (PCI), to be used as the amplification mechanism of a Coherent Electron Cooling (CeC) system, which we call Plasma Cascade Amplifier (PCA). In this work, we present our analytical estimate of the cooling force as expected from a PCA- based CeC system and compare it with the simulation results. As examples, we apply our analysis to a few possible CeC systems and investigate the evolution of the circulating ion beams in the presence of cooling. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS099 | ||
About • | paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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WEPMP001 | Proposed Nonlinear Injection Kicker for the Australian Synchrotron | injection, synchrotron, storage-ring, vacuum | 2300 |
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Future beamline development at the Australian Synchrotron requires free floor space within the straights for a short undulator and relocation of diagnostics. Our current injection method uses a four-dipole kicker configuration that perturbs the stored beam during injection while also taking up approximately 4 meters of valuable space. To free this valuable space and provide transparent injections to the beamlines, a single pulsed nonlinear magnetic field kicker (NLK) will be deployed. The NLK has a flat and zero field at the stored beam but maximum field where the injected beam is located off-axis. NLKs deflect only the injected beam, leaving the stored beam undisturbed. NLKs have been extensively prototyped by many facilities around the world already and can produce injection efficiencies of 99 % (see e.g. *). This paper presents the preliminary magnet design for installation of a NLK at the Australian Synchrotron. We discuss the beam dynamics and thermal transfer constraints on kicker placement, field-flatness and the magnet and ceramic chamber design for adaptation to our 3 GeV beam. Installation plans and other constraints for future deployment are also outlined.
* T. Pulampong and R. Bartolini, "A Non-linear Injection Kicker for Diamond Light Source", in: Proc. IPAC’13, pp. 2268-2270. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP001 | ||
About • | paper received ※ 15 May 2019 paper accepted ※ 24 May 2019 issue date ※ 21 June 2019 | ||
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WEPMP003 | Beam Dynamics and Diagnostics for the High Energy Beam Transport Line of MINERVA Project at SCK•CEN | septum, proton, pick-up, linac | 2304 |
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Funding: French research agency and technologies (ANRT), through the program CIFRE (2018/0080 ) supported by THALES AVS FRANCE SAS. MYRRHA will be a research infrastructure highlighted by the first prototype of a sub-critical nuclear reactor driven by a 600 MeV particle accelerator (ADS). This project aims at exploring the transmutation of long-lived nuclear wastes. A first phase is planned to validate the reliability of a 100 MeV/4 mA Protons LINAC carrying the beam toward an ISOL facility, prefiguring the real MYRRHA demonstrator at 600 MeV. This project is called MINERVA. This paper presents the status of the beam dynamic studies for the high energy beam transport lines at 100 MeV. In agreement with the project require-ments, we describe the specificities of these beam lines for which it is needed to implement a fast kicker-septum. This system will separate the beam between two main lines: toward the beam dump or the ISOL facility. We also describe the studies on the Beam Position Monitor (BPM) selected for MYRRHA. Part of this work was sup-port by the MYRTE project of the European Union. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP003 | ||
About • | paper received ※ 24 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | ||
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WEPMP009 | Renovation of Off-Axis Beam Injection Scheme for Next-Generation Photon Sources | septum, injection, vacuum, photon | 2318 |
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Funding: Work supported by Ministry of education, culture, sports, science and technology JAPAN (MEXT). Photon sources are looking for performance upgrades by pursuing higher photon brilliance and coherence these years. The trend is pushing the lattice design to lower the beam emittance, which naturally results in the narrower dynamic aperture. One bottleneck in the upgrades is a beam injection system capable of accumulating required beam intensity and keeping top-up operations with such narrow apertures. Beam injection with a nonlinear kicker and transverse/longitudinal on-axis injections are now in the limelight. However, these techniques still need time to be put into practical use. We take an alternative approach for the SPring-8 upgrade, SPring-8-II, renovating the off-axis beam injection scheme to address the following requirements for the coming diffraction-limited storage rings (DLSRs): minimizing of both injection beam amplitude and perturbation to stored beam, and topping-up functionality. This presentation will overview the renewed off-axis beam injection scheme and report the development status of the following three key components: 1) permanent magnet based DC septum magnet, 2) in-vacuum pulse septum magnet, and 3) twin kickers driven by a single solid state pulser. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP009 | ||
About • | paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | ||
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WEPMP010 | 8 Gev Slow Extraction Beam Test for Muon to Electron Conversion Search Experiment at J-PARC | extraction, timing, injection, electron | 2322 |
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A muon to electron conversion search experiment (COMET) planned at J-PARC needs 8 GeV bunched proton beams with a continuous 1 MHz pulse structure. In this experiment, an intensity ratio of the residual to the main pulsed beam, which is expressed as extinction, should be less than the level of 10-10. In RUN78 (Jan. to Feb., 2018), we have succeeded in slow extraction of 8 GeV protons with 7.3×1012 ppp, satisfies the COMET phase-I requirement, and the extinction derived from a timing measurement of secondary particles from the target shows a promising result. A mechanism to explain the measured extinction will be also described in this paper. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP010 | ||
About • | paper received ※ 01 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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WEPMP015 | Status of the R&D for HALS Injection System | injection, septum, storage-ring, vacuum | 2335 |
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Hefei Advanced Light Source (HALS) is a diffraction-limited synchrotron radiation source proposed by the NSRL. A comprehensive R&D program funded by the local government was initiated in the end of 2017. The program focuses on the key technologies including the injection, magnets, vacuum, mechanics, RF, etc. The formal construction of HALS is estimated to begin in 2020. This paper presents the R&D of the injection system, including the fast kicker, nanosecond pulser, NLK (non-linear kicker) and the septum magnet. Test results of the prototype fast kicker, pulsed power and the NLK are given and discussed. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP015 | ||
About • | paper received ※ 16 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | ||
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WEPMP016 | The Design and Preliminary Test of a Stripline Kicker for HALS | impedance, simulation, vacuum, high-voltage | 2338 |
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Stripline kicker is an important components of both on-axis longitudinal accumulation and on-axis swap out injection schemes in HALS (Hefei Advanced Light Source). After more than one year of R&D, construction of the first prototype is completed. The kicker performance is simulated by CST. The results show that in the range of 0~1GHz, on differential mode, S11 is less than - 23.7dB. In order to facilitate installation, the extension part and PTFE bracket were designed. The assembly of kicker and feedthrough has been tested with pulse generator and network analyser. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP016 | ||
About • | paper received ※ 25 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | ||
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WEPMP017 | A New Nonlinear Kicker Design and Measurement | injection, storage-ring, lattice, simulation | 2342 |
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Funding: Work supported by The National Key Research and Development Program of China(2016YFA0402000) and Pre-research Project of Hefei Advanced Light Source For the beam injection of HALS, a feasible injection scheme is proposed and a single-pulse nonlinear kicker has been designed for off-axis injection. The kicker has been improved on the basis of the previous designed one, and the structure of the kicker was simulated by OPERA, and the prototype has been processed and measured. The results showed that the kicker designed in this paper has less influence on stored beam and lower difficulty in location. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP017 | ||
About • | paper received ※ 26 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | ||
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WEPMP018 | A Novel Non-Linear Strip-Line Kicker Driven by Fast Pulser in Common Mode | injection, impedance, dynamic-aperture, multipole | 2345 |
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The next generation storage ring-based light sources adopt multi-bend achromat lattices to achieve a low emittance. The dynamic apertures of these machines are usually less than 10 mm so that the traditional pulsed local bump injection is difficult to achieve. Off-axis injection with a pulsed multipole or a non-linear kicker could be a viable solution which requires a moderate dynamic aperture of a few mm. In this paper, a novel non-linear kicker design is presented. Unlike pulsed sextupole or nonlinear kicker magnet, the nonlinear kicker we proposed is a traveling wave kicker with 2 strip-line electrodes driven by a nanosecond-level fast pulser in common mode. The disturbance to the stored beam is minimal since the perturbation is limited to the target bunch alone.
Work support by NSFC(11475200 and 11675194). |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP018 | ||
About • | paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | ||
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WEPMP026 | Emittance Dilution from the CERN Proton Synchrotron Booster’s Extraction Kickers | emittance, extraction, operation, proton | 2371 |
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Understanding the different sources of emittance dilution along the LHC injector chain is an important part of providing the high brightness proton beams demanded by the LHC Injectors Upgrade (LIU) project. In this context, the first beam-based measurements of the magnetic waveforms of the Proton Synchrotron Booster’s (PSB) extraction kickers were carried out and used to quantify the transverse emittance blow-up during extraction and transfer to the Proton Synchrotron (PS). In this contribution, the waveform measurement technique will be briefly outlined before the results and their implications for the LIU project and beam performance reach are discussed. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP026 | ||
About • | paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | ||
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WEPMP030 | LHC Injection Losses and Trajectories During Run 1 and 2 and Outlook to Injection of HL-LHC Beams | injection, extraction, operation, emittance | 2387 |
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The LHC turn-around time is impacted by the control of injection losses and trajectories. While shot-to-shot trajectory variations dominated the injection efficiency during LHC Run 1, several improvements of hardware and operational settings allowed for a high rate of successful injections during Run 2. Injection losses and trajectories are analysed and presented for the high intensity proton runs, as well as for different beam types used from the injectors. Based on this analysis, an outlook is shown for the HL-LHC era, where double the bunch intensity will have to be injected. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP030 | ||
About • | paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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WEPMP040 | Machine Protection Aspects of High-Voltage Flashovers of the LHC Beam Dump Dilution Kickers | operation, simulation, vacuum, high-voltage | 2418 |
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The LHC Beam Dump System is required to safely dispose of the energy of the stored beam. In order to reduce the energy density deposited in the beam dump, a dedicated dilution system is installed. On July 14, 2018, during a regular beam dump at 6.5 TeV beam energy, a high-voltage flashover of two vertical dilution kickers was observed, leading to a voltage breakdown and reduced dilution in the vertical plane. It was the first incident of this type since the start of LHC beam operation. In this paper, the flashover event is described and the implications analysed. Circuit simulations of the current in the magnet coil as well as simulations of the resulting beam sweep pattern are presented and compared with the measurements. The criticality of the event is assessed and implications for future failure scenarios are discussed. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP040 | ||
About • | paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | ||
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WEPMP042 | Reduction of Stored Beam Oscillations During Injection at Diamond Light Source | injection, simulation, storage-ring, timing | 2426 |
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At Diamond injection is performed by means a of a four kicker off-axis system, relying on a perfect timing and amplitude setting to produce a closed bump. Ageing of some of the kicker vessel components has progressively spoiled the performance of the system, causing oscillations in the stored beam. Various schemes to control these oscillations have been considered including introducing an additional compensating kicker, and installing a non-linear injection kicker. Results of simulations analysing these schemes are presented, along with measurements taken in the storage ring using an existing pinger magnet. The effects of the reduction on the quality of beam seen by beamlines is also considered. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP042 | ||
About • | paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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WEPMP043 | Injection Studies for the Proposed Diamond-II Storage Ring | injection, booster, septum, storage-ring | 2430 |
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The baseline design for the Diamond-II storage ring consists of a Modified-Hybrid 6-Bend Achromat, combining the ESRF-EBS low-emittance cell design with the DDBA mid-straight concept*,**. This cell design provides sufficient dynamic aperture to permit an off-axis injection scheme, provided the emittance of the injected beam is sufficiently low. In this paper we present simulations of an injection scheme using the anti-septum concept***, along with the design of an upgrade to the existing booster synchrotron. Alternate injection strategies are also discussed.
*ESRF Technical Design Study, ’The Orange Book’, (2014) **R. Bartolini et al., PRAB 21, 050701, (2018) ***C. Gough, M. Aiba, Proc. IPAC 2017, Copenhagen, Denmark, paper MOPIK104, (2017) |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP043 | ||
About • | paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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WEPMP052 | Proposed Hadron Injection into the Future eRHIC Collider | injection, dipole, septum, hadron | 2451 |
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Funding: *Work Supported by the US Department of Energy. The future eRHIC collider * will collide 5, 10, and 18 GeV polarized electrons with 250 GeV polarized protons, 210 GeV/u polarized 3He ions and other heavy ion species which are already produced by the RHIC accelerator. To increase the luminosity during collisions the number of circulating hadron bunches will increase to 330 and this requires a modification of the injection hadrons into the RHIC accelerator. This paper describes this injection scheme which is compatible with a design option which uses two hadron rings, one ring for accelerating the hadron beam and the other ring for storing the circulating beam to increase even further the integrated luminosity of the electron-hadron collisions. This two-hadron-rings option will be presented in the conference. tsoupas@bnl.gov * ICFA BD Newsletter No. 74 http://icfa-bd.kek.jp/ |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP052 | ||
About • | paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | ||
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WEPGW001 | Characterising Injected Beam Dynamics in the Australian Synchrotron Storage Ring | synchrotron, storage-ring, injection, multipole | 2458 |
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The injected beam trajectory at the Australian Synchrotron needs to be studied to assess the suitability of non-linear kicker installation. To achieve this, multiple diagnostics including cameras and radiochromic films were used to determine the position at several points inside the storage ring tunnels. This was used to infer the momentum data, and then simulated to model the new kicker installation. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW001 | ||
About • | paper received ※ 22 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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WEPGW036 | Archive System of Beam Injection Information at SuperKEKB | injection, background, operation, linac | 2550 |
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The archive system is one of the most important tools for the modern accelerators. It records the machine parameters during the operation so that we can retrieve and review the status of machine anytime later. SuperKEKB develops the injection archiver system. This system records the injection related parameters, pulse-by-pulse*. The information related with beam injections is fully recorded and it can be utilize to understand the condition of injection operation. Besides, the recorded data can be utilized also for the understanding of beam background related with injections.
* "Archive System for Injection Current at SuperKEKB", in Proc. of 15th Annual Meeting of PASJ, Nagaoka, Japan. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW036 | ||
About • | paper received ※ 30 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | ||
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WEPGW059 | A Preliminary Feasibility Study of Measurement of Quadrupolar Beam Oscillations at CSNS RCS | quadrupole, pick-up, space-charge, synchrotron | 2611 |
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In high intensity proton synchrotrons, linear and nonlinear betatron resonances cause beam loss. When the betatron tune spreads over a resonance line, the betatron oscillation amplitude will get larger, causing large beam loss. In the quadrupolar beam transfer function, the coherent space-charge tune shift of quadrupolar beam oscillations is used to determine the incoherent tune shift. China Spallation Neutron Source (CSNS) is a high intensity accelerator based facility consists of linear accelerator and the Rapid Cycle Synchrotron (RCS). A system of quadrupolar pick-up and kicker can be used for evaluating tune shifts and spreads. This paper will present already existing beam diagnostic instrumentation on CSNS/RCS, and discuss feasibility study of measurement of quadrupolar beam oscillations through adding a quadrupolar-type beam pick-up. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW059 | ||
About • | paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | ||
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WEPGW092 | Nanosecond-Latency Sub-Micron Resolution Stripline Beam Position Monitor Signal Processor for CLIC | feedback, detector, extraction, luminosity | 2705 |
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A high-resolution, low-latency stripline beam position monitor (BPM) signal processor has been developed for use in an intra-train feedback system for the Compact Linear Collider (CLIC). The processor was designed to have extremely low latency of order nanoseconds and a target position resolution of order 1 micron. The processor consists of a pair of diodes to form the difference and sum of a pair of stripline BPM inputs with microstrip filters to reduce out-of-band noise. The assembled prototype was optimized for use with the electron beam in the extraction line of the Accelerator Test Facility at the High Energy Accelerator Research Organization (KEK) in Japan but the underlying design is readily scaleable to a higher frequency response relevant for CLIC. A latency of 3 ns was measured in a testbench setup. We report the results of performance tests with beam in which the position resolution was measured to be c. 325 nm. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW092 | ||
About • | paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | ||
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WEPRB099 | Status Update of a Harmonic Kicker Development for JLEIC | multipole, cavity, coupling, simulation | 3047 |
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Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. An effort to develop the second prototype of the harmonic kicker for the Circulator Cooler Ring (CCR) of the Jefferson Lab Electron-Ion Collider (JLEIC) is under way. After beam dynamics studies and completion of a conceptual RF design of the kicker [1], further progress has been made toward the final mechanical design including the input power coupler (loop) design, tuner ports, multipacting studies. Furthermore, concerning the kicker’s compatibility with beam dynamics, the impact of RF multipole components was investigated and a scheme was developed to cancel out detrimental beam effects. 1. G. Park, et al, The Development of a New Fast Harmonic Kicker for the JLEIC Circulator Cooler Ring, TUPAL068, proceedings of IPAC 2018. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB099 | ||
About • | paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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WEPTS070 | First Measurements of Nonlinear Decoherence in the IOTA Ring | lattice, experiment, damping, optics | 3286 |
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Funding: This work has been supported by the U.S. Department of Energy Office of Science, Office of High Energy Physics under Award No. DE-SC00111340 The Integrable Optics Test Accelerator (IOTA), at Fermi National Laboratory is aimed at testing nonlinear optics for the next generation of high intensity rings. Through use of a special magnetic element the ring is designed to induce a large tune spread with amplitude while maintaining integrable motion. This will allow for the suppression of instabilities in high-intensity beams without significant reduction in dynamic aperture. One important aspect of this is the nonlinear decoherence that occurs when a beam is injected off axis or receives a transverse kick while circulating in the ring. This decoherence has been studied in detail, with simulations, for protons in IOTA both with and without space-charge. However, it has yet to be demonstrated experimentally. During the first phase of the IOTA experimental program, the ring is operated with 100 MeV electrons, allowing for the study of nonlinear optics without the complications introduced by space charge. Here we present measurements taken during the IOTA commissioning, and an analysis of the results. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS070 | ||
About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | ||
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WEPTS092 | 3d Start-to-End Simulations of the Coherent Electron Cooling | electron, simulation, FEL, plasma | 3329 |
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Coherent electron cooling (CeC) is a novel technique for rapidly cooling high-energy, high-intensity hadron beam. Two designs of coherent electron cooler, with a free electron laser (FEL) amplifier and a plasma-cascade micro-bunching amplifier, are cost effective and don’t require separation of hadrons and electrons. These schemes are used for the demonstration experiment in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). SPACE, a parallel, relativistic 3D electromagnetic Particle-in-Cell (PIC) code, has been used for simulation studies of these two coherent electron cooler systems. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS092 | ||
About • | paper received ※ 15 April 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | ||
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THPMP010 | Implementation of RF-KO Extraction at CNAO | extraction, betatron, synchrotron, resonance | 3469 |
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The National Centre for Oncological Hadrontherapy (CNAO) is a synchrotron based particle therapy facility. Both protons and carbon ions can be used for treatments. The main extraction system is based on ’amplitude-momentum selection’ driven by a betatron core, but RF-KO (Radio-Frequency Knock Out) is being implemented as an alternative extraction scheme, being more suitable for a future implementation of a ’multi energy extraction’ operation of the accelerator. With a double extraction possibility, CNAO would allow an interesting theoretical and experimental evaluation of the relative merits of the two extraction schemes. The RF deflector is already installed and the RF power generation is under commissioning. Extraction simulations and first results of the system are presented. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP010 | ||
About • | paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | ||
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THPMP017 | Design and Development of the Beamline System for a Proton Therapy Facility | dipole, proton, quadrupole, optics | 3488 |
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Funding: This work was supported by The National Key Research and Development Program of China, with grant No. 2016YFC0105305; and by National Natural Science Foundation of China (11375068). A proton therapy facility with multiple treatment rooms based on superconducting cyclotron scheme is under development in HUST (Huazhong University of Science and Technology). Design features and overview of development progress for the beamline system will be presented in this paper, which mainly focuses on prototype beamline magnets, a kicker magnet for fast beam switch, and the gantry beamline using image optics. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPMP017 | ||
About • | paper received ※ 29 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | ||
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THPRB026 | A 300 mm Long Prototype Strip-Line Kicker for the Heps Injection System | vacuum, injection, impedance, simulation | 3864 |
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In the High Energy Photon Source (HEPS), the dynamic aperture of machine is not large enough for off-axis injec-tion for its baseline 7BA lattice design. So, a group of superfast kickers with about 12 ns pulse bottom width are needed for on-axis swap out injection scheme. The design about a couple sets of 300 mm long strip-line kickers is presented. Five kickers as a module are placed in a stain-less steel vacuum vessel to solve the problem of longitu-dinal space restriction in injection area. So far, the proto-type development of strip-line kicker was completed. The results of time-domain reflectometer (TDR) test and high voltage pulse test show that the strip-line kicker can meet the requirement of the HEPS. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB026 | ||
About • | paper received ※ 06 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | ||
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THPRB036 | Development of Injection and Extraction Kickers for SuperKEKB Damping Ring | extraction, injection, power-supply, damping | 3890 |
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SuperKEKB is a double ring asymmetric collider to study the B meson physics, which is an upgrade project of KEKB. The 7 GeV electron (HER) and the 4 GeV positron ring (LER) collides at an interaction point. The positron beam produced by linac cannot meet the dynamic aperture restrictions of LER. Damping ring (DR) is required to reduce its injection emittance. Damping ring (DR) for SuperKEKB has two kicker magnets for the injection and the extraction, respectively. These kickers are required to meet the following specifications: (1) rise and fall time does not exceed 100 ns, (2) two bunches which are 96 ns apart must be kicked by single pulse, (3) the stability of peak current for the extraction kickers must be less than 0.1 %. Kicker magnets are designed as a conventional kicker with a ferrite core. The pulse shape is a double half sine for the two bunch injection. In order to achieve short rise time, a saturable inductance is used. The design and performance of kicker magnets and the power supplies are reported. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB036 | ||
About • | paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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THPRB037 | Improved Frequency Characteristics Using Multiple Stripline Kickers | feedback, controls, pick-up, extraction | 3893 |
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One of the important ingredient in the intra-bunch transverse feedback is a kicker. The frequency characteristics of the kicker suffers from the transit-time factor, sin(kl)/kl. We examine the frequency characteristics of multiple kickers system. Relation between the excitation patterns of the multiple kickers and the frequency characteristics are presented. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB037 | ||
About • | paper received ※ 23 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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THPRB054 | Design of a Ultrafast Stripline Kicker for Bunch-by-Bunch Feedback | FEL, impedance, feedback, HOM | 3931 |
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Lorentz force detuning and beam loading effect of the rf cavities will induce a slope of the cavity gradient. Combed with the cavity misalignments, transverse position of subsequent bunches will differ from each other. The CAEP THz Free Electron Laser facility(CTFEL) will have a fast transverse bunch-by-bunch feedback system on its test beamline, which is used to correct the beam position differences of individual bunches in the macro-pulses. The time response of the kicker is rigid for the interval of the micro-pulses is 18.5ns and will upgrade to about 2 ns, requiring impedance matching of the kicker with the power source and transmission system in a high bandwidth. Also, the electromagnetic field must reach the requirements of the beam parameters. In this paper, the structure design and the optimization of the geometric parameters of the ultrafast stripline kicker is presented. The characteristic impedance, transmission characteristics, field consistency are analyzed and optimized. And the feedback signal generation scheme for continuous bunch trains was proposed. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB054 | ||
About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | ||
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THPRB071 | Beam-Based Measurements on Two ±12.5 kV Inductive Adders, together with Striplines, for CLIC Damping Ring Extraction Kickers | flattop, extraction, damping, storage-ring | 3970 |
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The CLIC study is investigating the technical feasibil-ity of an electron-positron linear collider with high lumi-nosity 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, each of which consists of a set of striplines and two inductive adders, must provide ex-tremely stable field pulses. The DR extraction kicker system is the most demanding: specifications require a field uniformity within ±0.01% and pulses up to 900 ns flattop duration, at ±12.5 kV and 309 A, with ripple and droop of not more than ±0.02 % (±2.5 V), with respect to a reference waveform. Two prototype inductive adders have been designed and built at CERN, and have been tested with prototype striplines installed in the storage ring of the ALBA Synchrotron Light Source, in Spain. The stability of the kicker system, including the modulators, has been evaluated from the beam-based measure-ments and is reported in this paper. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB071 | ||
About • | paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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THPRB072 | Operational Experience of a Prototype LHC Injection Kicker Magnet with a Low SEY Coating and Redistributed Power Deposition | injection, operation, vacuum, electron | 3974 |
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Funding: This research was supported by the HL-LHC project In the event that it is necessary to exchange an LHC injection kicker magnet (MKI), the newly installed kicker magnet would limit HL-LHC operation for a few hundred hours due to dynamic vacuum activity. A surface coating with a low secondary electron yield, applied to the inner surface of an alumina tube to reduce dynamic vacuum activity without increasing the probability of UFOs, and which is compatible with the high voltage environment, was included in a prototype MKI installed in the LHC during the 2017-18 Year End Technical Stop. In addition, this MKI included an upgrade to relocate a significant portion of beam induced power from the yoke to a ’damping element’: this element is not at pulsed high voltage. The effectiveness of the upgrades has been demonstrated during LHC operation, hence a future version will include water cooling of this ’damping element’. This paper reviews dynamic vacuum around the MKIs and summarizes operational experience of the upgraded MKI. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB072 | ||
About • | paper received ※ 08 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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THPRB073 | Laboratory Measurements on Two ±12.5 kV Inductive Adders with ±0.02% Waveform Stability for CLIC Damping Ring Extraction Kickers | flattop, extraction, damping, collider | 3978 |
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The CLIC study is investigating the technical feasibil-ity 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. Each DR extrac-tion kicker system consists of a set of striplines and two pulse modulators. Specifications for this system require that the modulator produce pulses of 900 ns flattop dura-tion, ±12.5 kV and 305 A, with ripple and droop of not more than ±0.02 % (±2.5 V) with respect to a reference waveform. Inductive adder topology has been chosen for the pulse modulators. Two full-scale, 20-layer, 12.5 kV prototype inductive adders have been designed, built and tested at CERN. This paper presents the measurements of the stability of these adders for two different waveforms: a flat-top waveform and a controlled decay waveform, the latter of which is required to generate flat-top total field for the CLIC DR extraction stripline kicker. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB073 | ||
About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | ||
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THPRB074 | Studies Towards the New Beam Screen System of the LHC Injection Kicker Magnet for HL-LHC Operation | injection, operation, vacuum, simulation | 3982 |
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Although no heating issues were observed in the Large Hadron Collider’s (LHC) injection kicker magnets (MKIs) during Run 2, simulations suggest that for operation with the high intensity beams of the High Luminosity LHC (HL-LHC) project, the magnet’s ferrite yokes will reach their Curie temperature, thus leading to long turnaround times before a new beam can be safely injected into the machine. To safely enter the HL-LHC era, a campaign to redesign the kicker’s beam screen was launched. An improved beam-screen has already been implemented in an upgraded MKI, that was installed in the LHC tunnel in the Year End Technical Stop (YETS) 17/18, and has been successfully tested during 2018 operation. However, the improved design alone is not expected to be enough for HL-LHC operation, and further modifications are required. In this work, the approach to the design from an electromagnetic point of view is presented and different considered options are reported, emphasising the final design of the new beam screen system that is currently being implemented. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB074 | ||
About • | paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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THPRB075 | Transverse Impedance Measurements and Simulations of the LHC Injection Kicker Magnet | impedance, simulation, injection, coupling | 3986 |
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Kicker magnets contribute significantly to the total impedance budget of many accelerators. Of particular interest, from a beam stability point of view, is the transverse beam coupling impedance (TBCI) that is used to determine intensity limitations of a machine. Until recently, no conclusive TBCI data for the Large Hadron Collider (LHC) injection kicker magnets (MKIs) was available. However, in view of the upgrade of the MKIs for the High-Luminosity LHC (HL-LHC) project, the TBCI of the existing design needed to be estimated to be used as reference for an upgraded version. To that end, electromagnetic simulations were carried out to determine the dipolar and quadrupolar components of the TBCI in the two transverse planes. To validate the simulations, test bench measurements were performed using standard RF measurement techniques. In the present work, the results from TBCI simulations and measurements are reported and compared. Detailed descriptions of the methods and techniques used as well as the realization of the experimental set-up are also given. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB075 | ||
About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | ||
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THPRB078 | Performance Validation of the Existing and Upgraded PS Injection Kicker | injection, flattop, simulation, operation | 3994 |
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The CERN PS injection kicker KFA45 will be upgraded in the framework of the LHC Injector Upgrade (LIU) project to allow for injection of 2 GeV proton beams. This paper summarizes the recent efforts to validate beam based waveform measurements, Pspice simulations and current waveform measurements by direct magnetic field measurements in the aperture of the existing system. The magnetic probe, associated measurement hardware design and measurements results are discussed. The paper concludes with a performance comparison and an outlook to future waveform tuning possibilities. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB078 | ||
About • | paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | ||
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THPRB079 | DC Testing and Phase Resolved Partial Discharge Measurements of the New Trigger Transformers for the LHC Beam Dump Kickers | high-voltage, operation, GUI, power-supply | 3998 |
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During LS2 the LHC beam dump kicker pulse generators will be subject to a substantial consolidation program. One major part is the replacement of the existing GTO stack trigger transformer by a new more performant one. The transformer is assembled, moulded and tested in-house. Part of the validation procedure are standard DC tests and subsequent discharge monitoring as well as newly introduced phase resolved partial discharge measurements. This paper briefly highlights the trigger transformer parameters and construction and outlines in detail the testing and partial discharge measurements. It concludes with a comparison and analysis of the results of the different measurement techniques. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB079 | ||
About • | paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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THPRB091 | APPLICATION PROGRAMS FOR TPS BEAM TRIP ANALYSIS | power-supply, electron, photon, operation | 4032 |
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For the Taiwan Photon Source (TPS), the orbit inter-lock system is one of the most important machine pro-tection systems. It is the fastest and the most preferred system to detect abnormalities to prevent possible dam-ages caused by magnet power supply failures or subsys-tems failures. In order to monitor electron orbit changes during a beam trip, we developed the ’orbit monitoring and recording tool’, the ’TBT BPM analysis tool’ and the ’magnet power supply recording and analysis tool’ to assist us in the failure analysis as will be discussed in this paper. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB091 | ||
About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | ||
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THPRB092 | Reduction of Beam Induced RF-Heating in the Horizontal Stripline Kicker at the TPS | impedance, storage-ring, feedback, damping | 4035 |
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In preparation for 500 mA operation at the Taiwan Pho-ton Source (TPS), we redesigned the horizontal stripline kicker for the beam feedback system to gain a smaller loss factor with higher shunt impedance. We introduced ground fenders (see Fig. 1) to this new design which resulted in the reduction of the loss factor and substantial increase of the kicker shunt impedance. The transverse profile of the kicker electrodes was matched to the race-track beam pipe in the straight sections to minimize broadband impedance. The ground fenders can reduce the leakage of image currents through the gaps between the two strip line electrodes and also help to achieve a better impedance matching for the TEM modes in the transmission lines formed by the stripline electrodes and beam pipe in the kicker. The RF design and analysis of trapped resonant modes in the kicker were simulated by the 3-D electromagnetic code GdfidL [1]. Results of the RF design and analysis of trapped resonant modes will be discussed together with analytical estimates of coupled bunch instabilities at a beam current of 500 mA. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB092 | ||
About • | paper received ※ 17 April 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019 | ||
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THPRB099 | Applications of Dimension-Reduction to Various Accelerator Physics Problems | dynamic-aperture, sextupole, synchrotron, storage-ring | 4060 |
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Funding: DE-SC 0013571 DGE-1650441 OIA-1549132 Particle accelerators contain hundreds of magnets, making dimension-reduction techniques attractive when attempting to tune them. We apply this procedure to two different problems: correcting the orbit in the Cornell synchrotron and maximizing the dynamic aperture in the Cornell Electron Storage Ring (CESR). Cornell’s rapid cycling synchrotron accepts a 200 MeV beam from the linac and accelerates it to 6 GeV for injection into the CESR. ‘Kicker coils’ (dipole correctors) are used to correct for residual fields which would otherwise cause beam loss at the low energies. In such cases, it is usually advisable to measure and correct the orbit. However, one cannot measure the orbit without first getting the beam to circulate a few hundred times, by which point the low-energy orbit would already be mostly corrected. In order to speed up the process of empirical orbit tuning, we form knobs which have the largest effect on the global orbit error, so that the dimensionality of the space which must be searched may be greatly reduced. A small dynamic aperture in CESR will have adverse effects on beam lifetime and injection efficiency, and so ought to be maximized by tuning sextupoles. However, it is often unclear which sextupoles one ought to tune to alleviate the problem. Moreover, once the chromaticity is properly adjusted, it should not be changed. Since we expect resonance driving terms (RDTs) to have a large impact on the dynamic aperture, we develop sextupole knobs which change the RDTs as much as possible while leaving the chromaticity fixed. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB099 | ||
About • | paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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THPRB112 | Commission of the Transverse Bunch-by-Bunch Feedback at SPEAR3 | feedback, injection, vacuum, GUI | 4081 |
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Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515. Driven by the demand of suppressing transverse beam instabilities and developing novel short pulse operation modes in SPEAR3 storage ring, a wide-band transverse bunch-by-bunch feedback system has been recently commissioned for SPEAR3 storage ring. The system was demonstrated to be sufficient to suppress the transverse coupled bunch instabilities caused by trapped RF modes in one of the in vacuum insertion devices. A new function of beam instability interlock has been developed and is part of machine protection system for the in vacuum insertion device. In addition, the bunch-by-bunch feedback system serves as a indispensable diagnostic tool that enables us to measure machine parameters, beam impedance, and characteristics of the beam instability modes. In this paper, we describe the scheme and performance of the bunch-by-bunch feedback system at SPEAR3. |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB112 | ||
About • | paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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THPTS027 | Accelerator Implementing Development of Ceramics Chamber with Integrated Pulsed Magnet for Beam Test | vacuum, dipole, power-supply, injection | 4164 |
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We advance the development of Ceramics Chamber Integrated Pulsed Magnet (CCIPM) of air-core type as the application to low emittance ring with a narrow bore of light source accelerator in the future. The CCIPM is composed of ceramics cylinder of 60 mm diameter and four copper coils, which are implanted in the groove penetrated on the ceramic thickness along 30 cm length by silver brazing*. In addition to this structure, we succeeded in the implementations of cable connecting base that mechanically connect the coils and power supply with feeder lines and the pattern shape coating inside the ceramic cylinder. Improved brazing technique made it possible to braze the coil and the base on the coil at the same time that the coils are implanted in the ceramic thickness. Newly developed functional coating can reduce the eddy current caused by main magnetic field and pass the alternate component of beam wall current by capacitance structure. We report the details about the performance from the viewpoint of vacuum, magnetic field, insulation on the accelerator implementation with the approach to new technical development, and the preparation progress of beam test in beam-transport line.
* C. Mitsuda, et al., in Proc. IPAC2015, Richmond, VA, USA, p. 2879 |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS027 | ||
About • | paper received ※ 12 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | ||
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THPTS028 | Recent Improvements and Future Upgrades of the J-PARC Main Ring Kicker Systems | operation, power-supply, injection, extraction | 4167 |
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J-PARC Main Ring provides 500kW proton beam to the long baseline neutrino oscillation experiment (T2K). In order to increase the beam intensity to improve the sensitivity of the CP violation study in neutrino sector, shorter repetition cycle and higher beam current are required. As part of the upgrade project, both injection and fast-extraction (Fx) kicker magnet systems have been improved. Air-cooled non-inductive ceramic resistors are used as the impedance-matching terminator for the injection kicker magnet. Power consumption and temperature rise of the termination resistor due to the beam induced current was simulated to optimize the number of parallel of the resistors. Efficiency of cooling fans was also simulated to improve the cooling ability. For the Fx kicker magnet, a fast charging power supply of the modulator was developed and deployed to shorten the charging period from 1.4 sec to 0.2 sec. This paper represents the simulation results, performance of the charging unit and future upgrade plans. | |||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPTS028 | ||
About • | paper received ※ 21 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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FRXXPLS2 | Extinction Measurement of J-PARC MR with 8 GeV Proton Beam for the New Muon-to-Electron Conversion Search Experiment - COMET | proton, experiment, extraction, timing | 4372 |
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Funding: This work is partially supported by JSPS (Japan Society for the Promotion of Science) : KAKENHI 15K13492 and 16H00876 At J-PARC, extraction tests of a 8GeV pulsed proton beam from Main Ring (MR) have been successfully completed by a team drawn from the Accelerator Laboratory Group and the COherent Muon to Electron Transition (COMET) Experimental Group. The COMET Experiment aims to find new physics beyond the Standard Model by searching for the coherent neutrinoless conversion of a muon to an electron in muonic atoms, so-called mu-e conversion. This requires an extremely clean pulsed beam, and development of this beam plays a key role in the pursuit of the highest level of sensitivity. This successful extraction test is the clearing of a major milestone for the forthcoming experiment. The goal of the extraction tests was to confirm the beam quality under the customized MR operation mode. The J-PARC MR usually accelerates the proton beam (at one bunch per 600ns) up to 30GeV. But in the test, the MR instead accelerates the proton beam (at one bunch per 1.2us) up to 8GeV. The number of protons leaking between proton bunches, so-called EXTINCTION, must be less than one for every 1010 protons in the bunch. Extraction tests in the customized mode were conducted in January and February 2018 and resulted in many successes. In this test, leakage protons between bunches was successfully reduced below the objective of 10−10 of the number of protons in a bunch. This is a great success to guarantee the quality of proton beam required by COMET experiment. In addition, the time development of proton leakage was also precisely studied with several RF settings which enables us to further improve the extinction. In this paper, the result of extinction measurement and future prospect of beam extinction improvement is presented in addition to the detailed description of customized MR operation. |
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Slides FRXXPLS2 [13.427 MB] | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-FRXXPLS2 | ||
About • | paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | ||
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