Paper | Title | Other Keywords | Page |
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MOP013 | Focusing Solenoids for the HINS Linac Front End | solenoid, linac, dipole, alignment | 82 |
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Low energy part of the linac for the HINS project at Fermilab will use superconducting solenoids as beam focusing elements (lenses). While lenses for the conventional, DTL-type accelerating section of the front end require individual cryostats, in the superconducting accelerating sections solenoids will be installed inside rf cryomodules. Some of the lenses in the conventional and in the superconducting sections are equipped with horizontal and vertical dipole correctors. Lenses for the conventional DTL section are in the stage of production with certification activities ongoing at Fermilab. For the superconducting sections of the linac, several prototypes of focusing lenses were built and tested. Solenoid magnetic axis is used for alignment of the lenses in the transport channel of the accelerator. Corresponding technique has been developed at Fermilab and is used during certification of the production lenses for the DTL section. This report will summarize main design features, parameters, and test results of the focusing lenses of the linac. Magnetic axis alignment technique will also be described. |
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MOP025 | An Intermediate Structure SFRFQ Between RFQ and DTL | rfq, cavity, DTL, ion | 118 |
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Funding: supported by NSFC 10455001 |
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MOP032 | Upgrade of the Unilac High Current Injector RFQ | rfq, emittance, simulation, ion | 136 |
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Funding: Work supported by the European Community INTAS Project Ref. no. 06-1000012-8782. |
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MOP036 | The IFMIF-EVEDA RFQ: Beam Dynamics Design | rfq, emittance, space-charge, beam-losses | 145 |
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The IFMIF-EVEDA (Engineering Validation and Engineering Design Activities) project foresees the construction of a high intensity deuteron accelerator up to 9 MeV, with the characteristics required for the actual IFMIF facility. The linac will be installed in Rokkasho, and INFN is in charge of the construction of a 5 MeV, 125 mA, deuteron RFQ operating at 175 MHz. In this article the beam dynamics design of this challenging RFQ is described, namely the design, the main outcomes in terms of beam particles physics, and finally the study of mechanical and rf field error tolerances. The RFQ design method has been aimed to the optimization of the voltage and R0 law along the RFQ, the accurate tuning of the maximum surface field and the enlargement of the acceptance in the final part of the structure. As a result this RFQ is characterized by a length shorter than in all previous design, very low losses (especially at higher energy) and small rf power dissipation. |
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MOP054 | Experience with Stripping Carbon Foils in ALPI Super-Conducting Accelerator | cavity, ion, target, linac | 199 |
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The superconducting linac ALPI, injected either by a XTU tandem or by the superconducting RFQ of PIAVE, is composed by 3 cryostats of bulk Nb cavities (β=0.056) and 13 cryostats of Nb sputtered on Cu cavities (β=0.11 and β=0.13), for a total of 64 cavities and an equivalent voltage of 35MV. The linac is build up in two branches connected by an achromatic and isochronous U-bend. In January 2007 a stripping station equipped with carbon foils of different thickness was placed after 6 cryostats, before the U-bend, to test the feasibility of acceleration and transport of a charge enhanced beam. The study was performed with 4 different beams (Ca, Ar, Zr and Xe) and a complete data analysis has been carried out. |
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MOP060 | Quality Improvement of Laser-produced Protons by Phase Rotation and its Possible Extension to High Energies | laser, proton, ion, cavity | 214 |
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Funding: This work is supported by Advanced Compact Accelerator project by MEXT of Japanese Government and 21COE of Kyoto University, Center for Diversity and Universality in Physics. * Japanese Journal of Applied Physics (Express Letter), 46 (2007) L717-L720 |
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MOP069 | Beam Dynamics Simulations for a 15 MeV Superconducting Electron Linac Coupled to a DC Photo-Injector | cathode, simulation, target, solenoid | 236 |
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A 15 MeV accelerator scheme based on a dc photo-injector and a rf superconducting linac as been proposed as a new facility for radiography applications. The overall beam dynamics simulation process based on SUPERFISH and PARMELA codes will be reviewed. We present the results for the following beam operating conditions; acceleration of limited number of bunches, up to twenty electron micro-pulses of 100 ps time duration and 200 nC bunch charge, at 352 MHz repetition rate. |
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MOP076 | Integration of Fringe Field Alpha Magnets into the V-Code Beam Dynamics Simulation Tool | simulation, multipole, dipole, electron | 254 |
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Funding: This work was partially funded by DESY Hamburg and DFG (SFB 634). |
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MOP079 | Development of Modulating Permanent Magnet Sextupole Lens for Focusing of Pulsed Cold Neutrons | neutron, sextupole, dipole, permanent-magnet | 263 |
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We are developing a modulating permanent magnet sextupole lens to focus pulsed cold neutrons. It is based on the extended Halbach configuration to generate stronger magnetic field. In order to adjust the strength, the magnet is divided into two nested co-axial rings, where the inner ring is fixed and the outer ring can be rotated. Synchronizing the modulation with neutron beam pulse suppresses the chromatic aberration. These devices largely improve the utilization efficiency of neutrons, which makes even small linac based neutron sources practical. We have fabricated a half-scale model and studied its strength, torque and temperature rise during the operation. The main causes of the temperature rise are eddy-current loss in the poles made of soft magnetic material in inner ring and hysteresis loss. A laminated structure reduced the eddy-current loss. The temperature rise was suppressed to about half of the former model. We now study their B-H curve to optimize the thickness of the sheet. Annealing of the material is supposed to reduce the hysteresis loss, which will be tested soon. The experimental results of very-cold neutrons focusing with the half-scale model are also described. |
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MOP102 | Electron Beam Dynamics in the DARHT-II Linear Induction Accelerator | electron, induction, dipole, impedance | 311 |
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Funding: Work supported by USDOE under contract DE-AC52-06NA25396 *"Long-pulse beam stability experiments on the DARHT-II linear induction accelerator", Carl Ekdahl, et al., IEEE Trans. Plasma. Sci. Vol. 34, 2006, pp. 460-466. |
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MOP108 | Phase Law of a High Intensity Superconducting Linac | cavity, optics, linac, beam-losses | 328 |
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Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
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TUP077 | Development of Screen Monitor with a Spatial Resolution of Ten Micro-meters for XFEL/SPring-8 | electron, target, vacuum, undulator | 573 |
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At SPring-8, the 8 GeV linac for an X-ray free electron laser (XFEL) is now under construction. In order to realize the XFEL, highly qualified electron beams are required. A measurement of spatial structure of such beam is very important for the beam tuning of XFEL. The spatial structure is measured with a screen monitor, which we now develop. The resolution of the measurement is required within 10 um. The screen monitor comprises a vacuum chamber with a thin metal (100 um, SUS) foil to emit OTR, lenses for focusing and a CCD camera system. The main feature of the monitor is a bright and high-resolution optical system. In order to realize this system, the lenses are placed close to the foil, the distance between the lenses and the foil is 100 mm, and the lenses have a large diameter (2 in.). This optical-geometrical structure also contributes much to reduce the airy radius of a near field image. Although the range of an observation wavelength is wide as which is form 400 to 800 nm, the resolution of the measurement on the foil is calculated as 2.5 um. The experimental data of the developed screen monitor also suggested the same resolution. |
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TH203 | Beam Compression in Heavy-Ion Induction Linacs | plasma, target, ion, solenoid | 754 |
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Funding: This work was supported by the Office of Fusion Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231, DE-AC52-07NA27344, DE-AC02-76CH3073. |
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TH301 | Beam Dynamics Studies of the 8 GeV Linac at FNAL | linac, cavity, simulation, proton | 760 |
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Funding: This work was supported by the U.S. Department of Energy, Office of Scince, under contracts number DE-AC02-06CH11357 and No. W-31-109-ENG-38. |
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TH302 | Transport Limits in Periodic Focusing Channels | simulation, lattice, space-charge, beam-transport | 765 |
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It has been empirically observed in both experiments and particle-in-cell simulations that space-charge-dominated beams suffer strong growth in emittance and particle losses in alternating gradient quadrupole transport channels when the undepressed phase advance increases beyond about 85 degrees per lattice period. Although this criterion has been used extensively in practical designs of strong focusing intense beam transport lattices, the origin of the limit has not been understood. We propose a mechanism for the transport limit resulting from strongly chaotic classes of halo particle resonances near the core of the beam that allow near-edge particles to rapidly increase in oscillation amplitude when the space-charge intensity and the flutter of the matched beam envelope are both sufficiently large. A core particle model is applied to parametrically analyze this process and the results are compared with extensive particle simulations. |
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THP071 | Efficient Low-Beta H-Mode Accelerating Structures with PMQ Focusing | cavity, linac, beam-losses, quadrupole | 954 |
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We are developing high-efficiency room-temperature rf accelerating structures for beam velocities in the range of a few percent of the speed of light by merging two well-known ideas: H-mode cavities and the transverse beam focusing with permanent-magnet quadrupoles (PMQ). Combining electromagnetic 3-D modeling with beam dynamics simulations and thermal-stress analysis, we have found that the H-mode structures with PMQ focusing provide a very efficient and practical accelerator for light-ion beams of considerable currents. Such accelerating structures following a short RFQ can be used in the front end of ion linacs or in stand-alone applications such as a compact deuteron-beam accelerator up to the energy of a few MeV. |
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FR202 | Linacs for Future Muon Facilities | linac, optics, acceleration, cavity | 1119 |
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Funding: Supported in part by DOE STTR grant DE-FG02-05ER86253 |
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