| Paper | Title | Other Keywords | Page |
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| MOPGW007 | Electromagnetic Impulse of Beam Density F(x, y)G(z) | site, storage-ring, lattice, interaction-region | 75 |
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| We calculate the transverse impulse on a test particle as a bunch of charged particles beam passes by. It is often assumed, but seldom proven, that the EM field from a beam density distribution factored into transverse and longitudinal parts, F and G respectively, has also a factored form P(x, y)Q(z). This factorization is not possible for stationary charges. Contrastingly, it becomes increasingly accurate for ultra-relativistic particle beams. We give a general analysis, show how to develop the corrections in terms of integrals of F and derivatives of G. What is significant is that if we integrate over longitudinal coordinate z to find the transverse impulse on a witness charge, the correction terms integrate to zero leading to the impulse P(x, y)Integral[Q(z)] independent of bunch shape. If this result is already known, this paper serves as a reminder. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW007 | ||
| About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | ||
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| MOPGW068 | Crosstalk of Beam-Beam Effect and Longitudinal Impedance at CEPC | impedance, simulation, luminosity, collider | 247 |
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Funding: Project 11775238 supported by NSFC In conventional e+e− storage ring colliders, we only use lengthend bunch length in beam-beam simulation instead of considering impedance directly. It is no problem since the longitudinal dynamics is not sensitive to beam-beam interaction. But it is different since the bunch will also be lengthend during beam-beam interaction by beamstrahlung effect. It is very natural and more self-consistent to consider the longitudinal impedance in the beam-beam simulation. The simulation shows that the working point region of stable collision is slightly shifted by the longitudinal impedance. It is found that the vertical coherent oscillation may decreases the beam-beam limit with impedance at some working point. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW068 | ||
| About • | paper received ※ 15 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | ||
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| MOPRB024 | Beam-Gas and Beam-Thermal Photon Scattering in CEPC | scattering, photon, background, detector | 626 |
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| The Circular Electron Positron Collider (CEPC) is a proposed Higgs factory with center of mass energy of 240 GeV to measure the properties of Higgs boson and test the standard model accurately. Beam loss background in detectors is an important topic at CEPC. Beam-Gas scattering (BG) and Beam-Thermal photon scattering (BTH), although not so serious as Radiative Bhabha scattering (RBB) and Beamstrahlung (BS), are also important components of the beam induced backgrounds at CEPC due to the beam lifetime. In this paper, we evaluated the beam-gas and beam-thermal photon scattering in simulation and designed collimators to suppress the radiation level on the machine and the detector. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB024 | ||
| About • | paper received ※ 28 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | ||
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| MOPRB031 | Progress of Conceptual Study for the Accelerators of a 2-7GeV Super Tau Charm Facility at China | collider, luminosity, electron, operation | 643 |
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Funding: Supported by National Natural Science Foundation of China U1832169 and the Double Fist-Class University Project Foundation of USTC. This paper shows the progress of the conceptual study for the accelerators of a super tau charm facility in China. Since the BEPCII will finish its historical mission in 5~10 years and its upgrade plan will only achieve a small luminosity enhancement of 3~5 times, a new next generation tau-charm collider will play an irreplaceable role in future high energy physics study. The luminosity of this successor is about 5×1034cm−2s−1 pilot and 1×1035cm−2s−1 nominal, with the electron beam longitudinally polarized at the IP. The general scheme of the accelerators and the beam pa-rameters are shown. Several key technologies such as beam polarization and beam emittance diagnostics are also discussed. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB031 | ||
| About • | paper received ※ 14 May 2019 paper accepted ※ 17 May 2019 issue date ※ 21 June 2019 | ||
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| MOPRB045 | Future High Power Proton Drivers for Neutrino Beams | linac, proton, operation, neutron | 662 |
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Funding: ESSnuSB has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 7774. Over the last two decades, significant efforts were made through several international studies to identify and develop technical solutions for potential Neutrino Factories and Superbeam Facilities. With many questions now settled, as well as clearer R&D needs, various proposals are being made for future facilities in China, Europe, Japan and North America. These include both developing and adapting existing machines as well as green-field solutions. In this paper, we review all the major accelerator programmes aimed at delivering high-power proton beams for neutrino physics. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB045 | ||
| About • | paper received ※ 22 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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| MOPRB055 | First Partially Stripped Ions in the LHC (208Pb81+) | experiment, injection, collimation, operation | 689 |
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| The Gamma Factory initiative proposes to use partially stripped ion (PSI) beams as drivers of a new type of high intensity photon source. As part of the ongoing Physics Beyond Collider studies, initial beam tests with PSI beams have been executed at CERN. On 25 July 2018 lead ions with one remaining electron (208Pb81+) were injected and accelerated in the LHC for the first time. After establishing the injection and circulation of a few 208Pb81+ bunches, beam lifetimes of about 50 hours could be established at 6.5 TeV proton equivalent energy. This paper describes the setup of the beam tests and observations made. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPRB055 | ||
| About • | paper received ※ 29 April 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | ||
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| TUPMP020 | The Research on the Calibration of Direct-Current Current Transformers | power-supply, experiment, collider, data-acquisition | 1280 |
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| The measurement accuracy of direct current-current transformer (DCCT) is one of the key factors influencing the output of high-precision direct current power supply. In this paper, a calibration system designed by measuring resistance principle with a high accuracy direct current comparator (DCC) was presented for DCCT whose measurement accuracy is better than 10-5. The system can achieve high-precision calibration of DCCT within the measurement range of 0-400 A, and the uncertainty of the system calibration is better than 1.1×10-6 in the whole range. The accuracy and linearity of DCCT are tested to verify the accuracy of the whole calibration system, thereby the current accuracy of the magnet power supply can be further improved. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP020 | ||
| About • | paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | ||
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| TUPMP039 | Data-driven Controller Design Using the CERN Power Converter Control Libraries (CCLIBS) | controls, experiment, interface, survey | 1335 |
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| The data-driven control approach is a control methodology in which a controller is designed without the need of a model. Parametric uncertainties and the associated unmodeled dynamics are therefore irrelevant; the only source of uncertainty comes from the measurement process. The CERN Power Converter Control Libraries (CCLIBS) have been updated to include data-driven H-infinity control methods recently proposed in literature. In particular, a two-step convex optimization algorithm is performed for obtaining the 2-degree-of-freedom controller parameters. The newly implemented tools in CCLIBS can be used both for frequency response measurement of the load and for controller synthesis. A case study is presented where these tools are used for an application in the CERN East Area Renovation Project for which a high-precision 900 A trapezoidal current pulse is required with 450 ms flat-top and 350 ms ramp-up and ramp-down times. The tracking error must remain within ± 100 parts-per-million (ppm) during the flat-top (before the ramp-down phase starts). The magnet considered in the case study is of non-laminated iron type, hence the necessity of data-driven techniques since the dynamics of such a magnet is difficult to be modeled accurately (due to eddy currents losses). The Power Converter used is a SIRIUS 2P (with a current and voltage rating of 400 Arms and 450 V, respectively) whose digital control loop is regulated at a sampling rate of 5 kS/s. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPMP039 | ||
| About • | paper received ※ 08 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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| TUPRB059 | Solid State Amplifier of SC Linac for Shine | cavity, linac, LLRF, hardware | 1814 |
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| Shanghai HIgh repetition rate XFEL aNd Extreme light facility （SHINE）is a platform for technique and science research which energy is 8GeV, operated in CW-mode and beam current is 0.2mA. It include a LINAC of 8GeV, three undulator lines, three beam lines and ten experiment stations. SHINE is located underground 30 meters. The lengths of facility is 3kM and the length of LINAC is 1.2km. The acceleration architecture of LINAC consists of six hundred 1.3GHz and sixteen 3.9GHz TELSA type cavities. The 5.2kW SSA will drive the 1.3GHz superconductive cavities and 2kW SSA will power the 3.9GHz superconductive cavities. Four 1.3GHz prototypes of SSA have already been produced, the design and performance are showed in this paper. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB059 | ||
| About • | paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | ||
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| WEPGW014 | A Non-Invasive THz Spectrometer for Bunch Length Characterization at European XFEL | electron, FEL, radiation, diagnostics | 2495 |
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The European X-ray Free-Electron Laser provides one of the most powerful X-ray laser pulses to a wide range of experiments. These experiments strongly benefit from the exact knowledge of the electron bunch current profile and demand for stable and shortest-possible pulse lengths. During the 2018 summer shutdown, the 4-staged grating spectrometer CRISP* has been installed at a diffraction radiation (DR) beamline just upstream of the undulator beamline switchyard. The DR at final electron beam energies of up to 17.5 GeV enables non-invasive bunch length characterization based on form factor measurements down to a few micrometers. Fast detectors and electronics allow for the characterization of the whole bunch train with repetition rates above 1 MHz. This contribution will present commissioning results of the THz beamline as well as first measured form factors and reconstructed electron current profiles.
* S. Wesch et al., Nuclear Instruments and Methods in Physics Research Section A 665 (2011) pp. 40-47 |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW014 | ||
| About • | paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | ||
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| WEPGW032 | Evaluation of 2-D Transverse Beam Profile Monitor Using Gas Sheet at J-PARC LINAC | injection, linac, simulation, experiment | 2539 |
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| A transverse beam profile monitor, which detects ions or luminescence generated by the interaction between the beam and the gas molecules distributed in a sheet shape, has been developed in the J-PARC LINAC. To know about the gas density distribution of the sheet-shaped gas, which affects the intensity distribution of the detected signal, the calculation by the Monte Carlo simulation code was performed. The calculation results showed that the gas with a narrow width along beam direction distributes enough uniformly within a realistic beam cross-sectional size. In addition, the unsaturated region against the MCP voltage and the injected gas pressure are evaluated based on the measurement with a beam. The results showed that the measurement in the low injected gas pressure with the appropriate applied voltage range is important to measure the beam profile in the unsaturated region. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW032 | ||
| About • | paper received ※ 29 April 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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| WEPGW075 | Coupling Impedance Studies of the Current Transformers at ALBA | impedance, resonance, cavity, simulation | 2647 |
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| ALBA is equipped with two different current transformers (FCT and DCCT), and a third one (ICT) is now in design stage to be installed in 2019. A comparative study of the different currents transformers was carried out in order to characterize their contribution to longitudinal and transverse impedance. The gap in the vacuum chamber of the current transformers was varied in order to study its effect on the heat deposited by the beam in the corresponding device and on the resonance in the longitudinal impedance spectrum. The simulation results are compared to the experience with the existing current transformers in operation. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW075 | ||
| About • | paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | ||
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| WEPRB046 | Development of Flexible Waveguide for High Power High Vacuum Applications in S-band | GUI, vacuum, simulation, linac | 2909 |
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| A novel flexible waveguide is developed for S band 2856 MHz, which is a standard WR284 waveguide. The surface of the flexible waveguide is plated with Oxygen-free High Conductivity (OFHC) copper for the purpose of welding with the stainless steel flange in the vacuum furnace, for the flexible waveguide itself is made of brass. The prototype has got a certain amount of deformation which will be much more convenient for the connection between two hard waveguides. It also has a good measurement results of the lower power microwave test, and the 72 hours vacuum leakage test shows a satisfactory vacuum performance, no obvious surface collapse is observed. The high power test will be conducted after our high power test facility is available, which will tell us the maximal power level of the flexible waveguide prototype. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB046 | ||
| About • | paper received ※ 13 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | ||
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| WEPRB111 | Development of Nb3Sn Multicell Cavity Coatings | cavity, niobium, HOM, cryomodule | 3070 |
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Funding: Co-Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics. Nb3Sn films have the potential to augment niobium in SRF cavities. Besides single-cell cavity efforts to improve Nb3Sn films, we are working to replicate single-cell results onto the practical 5-cell CEBAF cavities. High quality factors (1011 at 2.0K and 10zEhNZeHn at 4.3 K) have been measured, but the cavities are typically limited by strong low-field Q-slopes and early quenches. Two of the cavities were selected to be assembled into a ’mock-up’ cavity pair unit, the standard step before installation into a cryomodule. Comparison of test results between VTA and pair test offered the first glimpse into post-processing effects on the cavity performance. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB111 | ||
| About • | paper received ※ 16 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | ||
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| WEPTS108 | Emittance Exchange in MICE | emittance, experiment, collider, simulation | 3378 |
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Funding: STFC, NSF, DOE, INFN, CHIPP and more The Muon Ionization Cooling Experiment, MICE, has demonstrated transverse emittance reduction through ionization cooling. Transverse ionization cooling can be used either to prepare a beam for acceleration in a neutrino factory or for the initial stages of beam cooling in a muon collider. Later stages of ionization cooling in the muon collider require the longitudinal emittance to be manipulated using emittance exchange and reverse emittance exchange, where emittance is exchanged from and to longitudinal phase space respectively. A wedge absorber within the MICE cooling channel has been used to experimentally demonstrate reverse emittance exchange in ionization cooling. Parameters for this test have been explored in simulation and applied to experimental configurations using a wedge absorber when collecting data in the MICE beam. This analysis of reverse emittance exchange is presented in detail. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS108 | ||
| About • | paper received ※ 14 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019 | ||
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