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MOPMR032 | Measurement of Beam Size with a SR Interferometer in TPS | radiation, synchrotron, synchrotron-radiation, monitoring | 313 |
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Taiwan Photon Source (TPS) has operated since 2015. An optical diagnostic beamline is constructed in section 40 of TPS for the diagnosis of the properties of the electron beam. One instrument at this beamline is a synchrotron radiation interferometer (SRI), which is operated to monitor the beam size. In this paper, we present the beamline structure and recent results of measurement with the SR interferometer. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR032 | ||
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MOPOY058 | Removing Known SPS Intensity Limitations for High Luminosity LHC Goals | impedance, vacuum, simulation, emittance | 989 |
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In preparation of the SPS as an LHC injector its impedance was significantly reduced in 1999 - 2000. A new SPS impedance reduction campaign is planned now for the High Luminosity (HL)-LHC project, which requires bunch intensities twice as high as the nominal one. One of the known intensity limitations is a longitudinal multi-bunch instability with a threshold 3 times below this operational intensity. The instability is presently cured using the 4th harmonic RF system and controlled emittance blow-up, but reaching the HL-LHC parameters cannot be assured without improving the machine impedance. Recently the impedance sources responsible for this instability were identified and implementation of their shielding and damping is foreseen during the next long shutdown (2019 - 2020) in synergy with two other important upgrades: amorphous carbon coating of (part of) the vacuum chamber against the e-cloud effect and rearrangement of the 200 MHz RF system. In this paper the strategy of impedance reduction is presented together with beam intensity achievable after its realisation. The potential effect of other proposals on remaining limitations is also considered. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY058 | ||
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TUPMB042 | Sweet Spot Designs for Interaction Region Septum Magnets | dipole, hadron, quadrupole, electron | 1196 |
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Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. A fundamental consideration in designing a high energy collider Interaction Region with electron beams is to avoid production of excessive experimental detector background due to synchrotron radiation. Circumventing such radiation is especially problematic with colliding beams having quite different magnetic rigidities as occurs in both electron-hadron and asymmetric-momentum electron colliders where one must shield an incoming electron beam from the strong magnetic fields needed to focus the other beam. After reviewing some magnetic configurations used to date, we introduce a new 'sweet spot' coil concept that was invented for the eRHIC project proposed at BNL. Sweet spot coils have conductors arranged so that there is an open, low field strength path through the main high field superconducting coil structure. Sweet spot configurations tend to be more efficient than other active and passive shielding solutions. Dipole and quadrupole sweet spot magnet designs examples are presented in this paper along with ongoing R&D to implement and test these concepts. |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMB042 | ||
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TUPMR025 | Design of the LBNF Beamline | target, proton, operation, extraction | 1291 |
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Funding: Work supported by the Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. The Long Baseline Neutrino Facility (LBNF) will utilize a beamline located at Fermilab to provide and aim a neutrino beam of sufficient intensity and appropriate energy range toward DUNE detectors, placed deep underground at the SURF Facility in South Dakota. The primary proton beam (60 - 120 GeV) will be extracted from the MI-10 section of Fermilab's Main Injector. Neutrinos are produced after the protons hit a solid target and produce mesons which are subsequently focused by magnetic horns into a 194 m long decay pipe where they decay into muons and neutrinos. The parameters of the facility were determined taking into account the physics goals, spacial and radiological constraints and the experience gained by operating the NuMI facility at Fermilab. The Beamline facility is designed for initial operation at a proton-beam power of 1.2 MW, with the capability to support an upgrade to 2.4 MW. LBNF/DUNE obtained CD-1 approval in November 2015. We discuss here the design status and the associated challenges as well as the R&D and plans for improvements before baselining the facility. |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR025 | ||
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TUPMR055 | Solid Targetry for the Isotope Production Facility at the KOMAC 100 MeV Linac | target, proton, coupling, isotope-production | 1384 |
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Funding: *This work was supported by the Ministry of Science, ICT and Future Planning of the Korean Government. The construction of the isotope production facility was recently completed on the 100 MeV proton linac at the KOMAC (Korea multi-purpose accelerator complex). To produce the Sr-82 and Cu-67, we have prepared the solid targetry which consist of target transportation system , target cooling system and a hot-cell for remote handling. The Isotope production targets are made of RbCl pellet and stainless steel cladding. For the proton beam irradiation, the targets are transported by target drive system which consist of drive chain and guide rail by remotely. In this paper, we will report the detailed design, fabrication and operation status of the solid targetry at the KOMAC isotope production facility. |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR055 | ||
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TUPMW004 | Assessment and Mitigation of the Proton-Proton Collision Debris Impact on the FCC Triplet | detector, quadrupole, proton, dipole | 1410 |
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The Future Circular hadron Collider (FCC-hh), which is designed to operate at a centre-of-mass energy of 100 TeV and to deliver ambitious targets in terms of both instantaneous and integrated luminosity, poses extreme challenges in terms of machine protection during operation and with respect to long-term damages. Energy deposition studies are a crucial ingredient for its design. One of the relevant radiation sources are collision debris particles, which de- posit their energy in the interaction region elements and in particular in the superconducting magnet coils of the final focus triplet quadrupoles, to be protected from the risk of quenching and deterioration. In this contribution, the collision debris will be characterised and expectations obtained with FLUKA will be presented, including magnet lifetime considerations. New techniques including crossing angle gymnastics for peak dose deposition mitigation (as recently introduced in the framework of the LHC operation), will be discussed. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW004 | ||
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TUPMW005 | Characterization of the Radiation Field in the FCC-hh Detector | detector, neutron, dipole, radiation | 1414 |
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As part of the post-LHC high-energy program, a study is ongoing to design a new 100 km long hadron collider, which is expected to operate at a centre-of-mass energy of 100 TeV and to accumulate up to 30 ab−1, with a peak instantaneous luminosity that could reach 30 1034cm−2s−1. In this context, the evaluation of the radiation load on the detector is a key step for the choice of materials and technologies. In this contribution, a first detector concept will be presented. At the same time, fluence distributions, relevant for detector occupancy, and accumulated damage on materials and electronics will be shown. The effectiveness of a possible shielding configuration, intended to minimise the background in the muon chambers and tracking stations, will be presented. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW005 | ||
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TUPMW016 | Effect of the LHC Beam Screen Baffle on the Electron Cloud Buildup | electron, simulation, proton, dipole | 1454 |
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Funding: Research supported by the High Luminosity LHC project Electron Cloud (EC) has been identified as one of the major intensity-limiting factors in the CERN Large Hadron Collider (LHC). Due to the EC, an additional heat load is deposited on the perforated LHC beam screen, for which only a small cooling capacity is available. In order to preserve the superconducting state of the magnets, pumping slots shields were added on the outer side of the beam screens. In the framework of the design of the beam screens of the new HL-LHC triplets, the impact of these shields on the multipacting process was studied with macroparticle simulations. For this purpose multiple new features had to be introduced in the PyECLOUD code. This contribution will describe the implemented simulation model and summarize the outcome of this study. |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW016 | ||
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TUPMW018 | Radiation Load Optimization in the Final Focus System of FCC-hh | radiation, quadrupole, luminosity, optics | 1462 |
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With a center-of-mass energy of up to 100 TeV, FCC-hh will produce highly energetic collision debris at the Interaction Point (IP). Protecting the final focus quadrupoles from this radiation is challenging, since the required amount of shielding placed inside the magnets will reduce the free aperture, thereby limiting the β* reach and luminosity. Hence, radiation mitigation strategies that make best use of the available aperture are required. In this paper, we study the possibility to split the first quadrupole Q1 into two quadrupoles with individual apertures, in order to distribute the radiation load more evenly and reduce the peak dose. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW018 | ||
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TUPOR003 | CSR-Driven Longitudinal Single Bunch Instability with Negative Momentum Compaction Factor | synchrotron, damping, radiation, electron | 1651 |
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Acceptable agreement is found between experimental results obtained at the Metrology Light Source (MLS) operated with negative momentum compaction factor, α, and theoretical estimates of the CSR-driven threshold currents. Theoretical instability thresholds are estimated by numerically solving the Vlasov-Fokker-Planck equation and/or by multi particle tracking and taking into account the shielded CSR-interaction. Some of the issues with the calculations, the determination of the theoretical thresholds as well as the derivation of a general scaling law will be presented | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR003 | ||
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TUPOR006 | Systematic Studies of Short Bunch-Length Bursting at ANKA | radiation, synchrotron, synchrotron-radiation, electron | 1662 |
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Funding: Supported by the German Federal Ministry of Education and Research (05K13VKA), the Helmholtz Association (VH-NG-320) and by the Helmholtz International Research School for Teratronics (HIRST). At ANKA, the Karlsruhe synchrotron radiation source, the so called short bunch-length operation mode allows the reduction of the bunch length down to a few picoseconds. The micro-bunching instability resulting from the high degree of longitudinal compression leads to fluctuations in the emitted intensity in the THz regime, referred to as bursting. For extremely compressed bunches at ANKA bursting also occurs, in a certain current range, below the main bursting threshold. This contribution shows measurements of this short bunch-length bursting and makes first comparisons with theory. |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR006 | ||
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WEPMR046 | Thermal Analysis of the Injection Beam Dump at J-PARC RCS | radiation, injection, proton, synchrotron | 2380 |
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In the J-PARC accelerator facility, 400 MeV H− ions are injected from linac to rapid cycling synchrotron (RCS). A thin graphite foil with the thickness of about 300 ug/cm2 is located at the injection point to strip two electrons from H− ion and convert it to proton. The charge stripping efficiency is usually more than 99.7 %. In other words, less than 0.3 % H− ions are not accurately exchanged to protons. Most of those remaining H− ions or H0 atoms (stripped only one electron from H− ion) are eventually converted to protons by second and third graphite foils and transported to the beam dump. This beam dump consists of an iron block with the size of 0.3×0.3×0.4 m3 for beam stop and the iron block with the size of 3×3×2.5 m3 and concrete with the size of 6×6×6 m3 around the iron block for the radiation shielding. The radiation shielding was designed to endure the 4 kW proton beam to the beam dump. In this presentation, we show the thermal analysis of the beam dump and compare it to the real operation. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR046 | ||
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WEPMR056 | Septum Magnet using a Superconducting Shield | septum, extraction, radiation, dipole | 2402 |
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A field-free region can be created within a dipole magnet using a superconducting shield, which maintains persistent eddy currents induced during the ramp-up of the magnet. We will study the possibility to realize a high-field superconducting septum magnet using this principle. Properties of different configurations will be presented, and compared to the requirements of the FCC dump system. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMR056 | ||
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WEPOR023 | Radiation Shielding Considerations for CEPC-SPPC | radiation, synchrotron-radiation, synchrotron, monitoring | 2722 |
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A planned project CEPC-SPPC is under-researched by IHEP, CAS, China. Due to its big circumference and high energy, the radiation shielding issues should be treated more serious than ever whether for the machine itself or the worker and the public. In this paper, we briefly introduce the configurations and parameters of the machine, the tools and principle used in the radiation shielding design, and discuss the preliminary result for the shielding of main tunnel and the synchrotron radia-tion. Some radiation protection issues are listed to be resolved next. All the aspects presented should be dis-cussed and verified, any other unmentioned radiation protection problems will be excavated in the future.
CEPC: Circular Electron-Positron Collider SPPC: Super Proton-Proton Collider IHEP: Institute of High Energy Physics CAS: Chinese Academy of Sciences |
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DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR023 | ||
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THPOW038 | First Results from Two Novel In-vacuum Magnetic Field Measurement Devices as Built at HZB | vacuum, feedback, undulator, controls | 4028 |
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The characterization of cryogenic in vacuum permanent magnet undulators with periods less than 20 mm and correspondingly narrow gaps requires new in-vacuum measurement systems. The positioning accuracy of the HZB in-vacuum Hallprobe bench has substantially been improved (a few μm) with appropriate feedback systems. A new in-vacuum cable tray has been developed. Another system for field integral measurements, an in-vacuum moving wire, is under commissioning. Both devices are presented. | |||
DOI • | reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW038 | ||
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