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MOZAPA02 | Commissioning Highlights of the Spallation Neutron Source | SNS, linac, target, proton | 29 | ||||
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The Spallation Neutron Source (SNS) is a second generation pulsed neutron source at Oak Ridge National Laboratory. The SNS is funded by the U.S. Department of Energy's Office of Basic Energy Sciences and is dedicated to the study of the structure and dynamics of materials by neutron scattering. A collaboration composed of six national laboratories (ANL, BNL, TJNAF, LANL, LBNL, ORNL) is responsible for the design and construction of the various subsystems. With the official start in October 1998, the operation of the full facility has begun in late spring 2006 delivering a 1.0 GeV proton beam with a pulse length of approximately 700 nanoseconds on a liquid mercury target. Within the next two years a beam power of more than one MW should be achieved. The multi-lab collaboration provided a large variety of expertise in order to enhance the beam power delivered by the accelerator by almost an order of magnitude compared to existing neutron facilities. The SNS linac consists of a room temperature and superconducting (sc) structures and is the first pulsed high power sc linac in the world. The compressor ring and the target are the final subsystems that were commissioned during early 06.
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Transparencies
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MOPCH077 | The Collector Ring CR of the FAIR Project | kicker, antiproton, pick-up, injection | 208 | ||||
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The Collector Ring is a storage ring in the framework of the FAIR project. It has the purpose of stochastic precooling of both rare isotope and antiproton beams and of measurung nuclear masses in an isochronous setting. The paper discusses progress in the development of magnet systems, rf systems, injection/extraction strategies and stochastic cooling systems. Finally it is discussed how to confirm the predicted performance of the slotline electrodes developed recently for stochastic cooling.
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MOPCH079 | Ion Optical Design of the Heavy Ion Synchrotron SIS100 | ion, lattice, synchrotron, acceleration | 214 | ||||
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We present the ion optical design of SIS100, which is the main synchrotron of the FAIR project. The purpose of SIS100 is the acceleration of high intensity heavy ion and proton beams and the generation of short compressed single bunches for the production of secondary beams. Since ionization in the residual gas is the main loss mechanism, a new lattice design concept had to be developed, especially for the operation with intermediate charge state heavy ions. The lattice was optimized to generate a peaked loss distribution in charge separator like lattice cells. Thereby it enables the control of generated desorption gases in special catchers. For bunch compression, the lattice provides dispersion free straight sections and a low dispersion in the arcs. A special difficulty is the optical design for fast and slow extraction, and the emergency dumping of the high rigidity ions within the same short straight section.
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MOPCH099 | Performance and Capabilities of the NASA Space Radiation Laboratory at BNL | ion, booster, BNL, RHIC | 270 | ||||
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The NASA Space Radiation Laboratory (NSRL) at BNL has been in operation since 2003. The first commissioning of the facility took place beginning in October 2002 and the facility became operational in July 2003. The facility was constructed in collaboration with NASA for the purpose of performing radiation effect studies for the NASA space program. The NSRL is capable of making use of protons and heavy ions in the range of 0.05 to 3 GeV/n slow extracted from BNL's AGS Booster. It is also capable of making use of protons and heavy ions fast extracted from the AGS Booster. Many different beam conditions have been produced for experiments at NSRL, including very low intensity In this report we will describe the facility and its' performance over the eight experimental run periods that have taken place since it became operational. We will also describe the current and future capabilities of the NSRL.
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MOPCH100 | Polarized Proton Acceleration in the AGS with Two Helical Partial Snakes | resonance, polarization, AGS, injection | 273 | ||||
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Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult: the depolarizing resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions and it is not feasible in the AGS since straight sections are too short. Recently, two helical partial snakes with double pitch design have been built and installed in the AGS. With careful setup of optics at injection and along the ramp, this combination can eliminate intrinsic and imperfection depolarizing resonances encountered during acceleration. This paper presents the accelerator setup and preliminary results. The effect of horizontal intrinsic resonances in the presence of two partial snakes are also discussed.
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MOPCH126 | Accelerator Research on the Rapid Cycling Synchrotron at IPNS | acceleration, proton, synchrotron, injection | 339 | ||||
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The Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory is a national user facility for neutron scattering. Neutrons are produced by 70 ns pulses of protons (~3x 1012 protons per pulse) impacting a depleted-uranium target at a pulse repetition rate of 30 Hz. Three accelerators in series (a 750 keV Cockcroft-Walton, 50 MeV Alvarez linac accelerating H- ions, and a 450 MeV rapid-cycling proton synchrotron) provide the beam that is directed to the target. New diagnostics and a third rf cavity that can be operated at either the fundamental or second harmonic of the ring frequency have recently been installed and an experimental program established to try to gain understanding of an instability that limits the charge-per-bunch in the RCS. This program will be described, and preliminary results presented.
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MOPCH130 | Simulations for SNS Ring Commissioning | target, RTBT, injection, quadrupole | 348 | ||||
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In preparation for SNS ring commissioning, a number of operational issues have been studied using ORBIT Code simulations. These include beam injection without the use of time-dependent painting, beam accumulation and transport to the extraction dump and to the target, optimal painting schemes for various beam intensities, detailed tracking through the extraction septum with fully correct geometry, quadrupole current constraints in the ring-to-target transfer line (RTBT), and detailed modeling of H minus carbon foil stripping at injection. All these studies incorporated detailed physics including beam-foil interactions, symplectic single particle tracking, space charge and impedances, and losses due to apertures and collimation.
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MOPCH131 | SNS Ring Commissioning Results | target, injection, beam-losses, linac | 351 | ||||
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The Spallation Neutron Source (SNS) comprises a 1.5-MW, 60-Hz, 1-GeV linac, an accumulator ring, associated beam lines, and a spallation neutron target. Construction began in 1999 and the project is on track to be completed in June 2006. By September 2005 the facility was commissioned up through the end of the superconducting linac, and in January 2006 commissioning began on the High Energy Beam Transport beam line, the accumulator ring, and the Ring to Target Beam Transport beam line up to the Extraction Beam Dump. In this paper we will discuss early results from ring commissioning including a comparison of achieved vs. design beam machine parameters and the maximum beam intensity achieved to date.
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MOPCH136 | China Spallation Neutron Source Accelerators: Design, Research, and Development | linac, injection, target, synchrotron | 366 | ||||
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The Beijing Spallation Neutron Source (BSNS) is a newly approved high power accelerator project based on a H- linear accelerator and a rapid cycling synchrotron. During the past year, several major revisions were made to the design including the type of the front end, linac frequency, transport layout, ring lattice, and type of ring components. Possible upgrade paths were also laid out: based on an extension of the warm linac, the ring injection energy and the beam current could be raised doubling the beam power on target to reach 200 kW; an extension with a superconducting RF linac of similar length could raise the beam power near 0.5 MW. Based on these considerations, research and development activities are started. In this paper, we discuss the rationale of design revisions and summarize the recent work.
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MOPCH174 | Optimization of the BCP Processing of Elliptical Nb SRF Cavities | simulation, LEFT, insertion, DESY | 469 | ||||
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Bulk niobium (Nb) electropolished SRF cavities performing at or above 35 MV/m is an aggressive goal recently put forth by the International Linear Collider (ILC) collaboration. Buffered chemical polishing (BCP) is still the most cost effective and least complex processing technique known today to optimize the surface properties of high gradient single crystal and relatively low gradient polycrystalline SRF cavities. BCP will be the preferred chemical process in the production of the nine-cell third harmonic 3.9 GHz cavities at Fermilab. The internal shape of these cavities will result in uneven material removal rates between iris and equator of the cells. We will describe a thermal-fluid finite element model adopted to simulate the etching process, and thus revealing the issues at hand. Experimental work, such as flow visualization tests performed to verify the simulation, will also be discussed. Finally we are presenting results obtained with a novel device, which allows to homogenize the flow pattern and to resolve the problem.
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MOPLS060 | Design of an Interaction Region with Head-on Collisions for the ILC | optics, quadrupole, dipole, luminosity | 682 | ||||
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An interaction region with head-on collisions is considered an alternative to the baseline configuration of the International Linear Collider, including two interaction regions with finite crossing-angles (2 and 20 mrad). Although more challenging from the point of view of the beam extraction, the head-on scheme is favoured by the experiments because it allows a more convenient detector configuration, particularly in the forward region. The optics of the head-on extraction is revisited by separating the e+ and e- beams horizontally, first by electrostatic separators operated at their LEP nominal field and then using a defocusing quadrupole of the final focus beam line. In this way the septum magnet is protected from the beamstrahlung power. Newly optimized final focus and extraction optics are presented, including a first look at post-collision diagnostics. The influence of parasitic collisions is shown to lead to a region of stable collision parameters. Beam and beamstrahlung photon losses are calculated along the extraction elements. Issues concerning the design of the large bore superconducting final focus magnets, common to both incoming and outgoing beams, are considered.
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MOPLS061 | Optimization of the e-e- Option for the ILC | luminosity, simulation, quadrupole, optics | 685 | ||||
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The e-e- running mode is one of the interesting physics options for the International Linear Collider. The luminosity for e-e- collisions is reduced by mutual defocusing due to the strong electromagnetic fields that the bunches experience during collisions. The resulting beamstrahlung energy loss and beam-beam deflection angles as function of the vertical transverse offset are different compared to the e+e- collisions. In this paper, the dependence of these observables with the offset for different beam sizes has been analysed to optimize performances for the e-e- mode, taking into account the requirements of the beam-beam deflection based intra-train feedback system. A first study of the implications for the final focus and extraction line optics is also presented for the cases of the 2mrad and 20mrad ILC base line crossing angle geometries.
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MOPLS077 | The 2mrad Crossing Angle Interaction Region and Extraction Line | optics, quadrupole, beam-transport, interaction-region | 730 | ||||
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A complete optics design for the 2mrad crossing angle interaction region and extraction line was presented at Snowmass 2005. Since this time, the design task force has been working on developing and improving the performance of the extraction line. The work has focused on optimising the final doublet parameters and on reducing the power losses resulting from the disrupted beam transport. In this paper, the most recent status of the 2mrad layout and the corresponding performance are presented.
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MOPLS078 | Benchmarking of Tracking Codes (BDSIM/DIMAD) using the ILC Extraction Lines | beam-transport, quadrupole, optics, SLAC | 733 | ||||
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The study of beam transport is of central importance to the design and performance assessment of modern particle accelerators. In this work, we benchmark two contemporary codes - DIMAD and BDSIM, the latter being a relatively new tracking code and built within the framework of GEANT4. We consider both the 20mrad and 2mrad extraction lines of the International Linear Collider and perform disrupted beam tracking studies of heavily disrupted post-collision electron beams. We find that the two codes in most cases give an equivalent description of the beam transport.
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MOPLS080 | A Laser-wire System at the ATF Extraction Line | laser, electron, photon, optics | 738 | ||||
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A new laser-wire system has been installed at the ATF extraction line at KEK, Tsukuba. The system aims at a micron-scale laser spot size and employs a mode-locked laser system. The purpose-built interaction chamber, light delivery optics, and lens systems are described, and the first results are presented.
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MOPLS082 | Simulation of the ILC Collimation System Using BDSIM, MARS15 and STRUCT | collimation, simulation, radiation, SLAC | 744 | ||||
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The simulation codes STRUCT, MARS15 and BDSIM are used to simulate in detail the collimation section of the ILC. A comparative study of the collimation system performance is performed, and the key radiation loads are calculated. Results for the latest ILC designs are presented together with their implications for future design iterations.
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MOPLS091 | First Design of a Post Collision Line for CLIC at 3 TeV | CLIC, photon, dipole, beam-losses | 765 | ||||
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As part of the Post collision diagnostic task of the ILPS work-package of EuroTeV we discuss a design of the beam line between the interaction point and the beam dump for CLIC with a center-of-mass energy of 3 TeV. The design is driven by the requirement to transport the beam and all secondaries such as beamstrahlung and coherent pairs to the beam dump with minimal losses. Moreover, we discuss the integration of novel diagnostic methods into the post collision beam line based on the detection of coherent pairs and monitoring the beam profile of the primary beam.
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MOPLS097 | Progress on the CTF3 Test Beam Line | CLIC, CTF3, lattice, quadrupole | 783 | ||||
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In CLIC, the RF power to accelerate the main beam is produced by decelerating a drive beam. The test beamline (TBL) of the CLIC test facility (CTF3) is designed to study and validate the stability of the drive beam during deceleration. This is one of the R&D items required from the International Linear Collider Technical Review Committee to demonstrate feasibility of CLIC. It will produce 30 GHz rf power in the GW range and allow to benchmark computer codes used for the CLIC decelerator design. Different options of this experimental beam line are discussed.
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MOPLS122 | Design of the ILC Prototype FONT4 Digital Intra-train Beam-based Feedback System | feedback, kicker, linear-collider, KEK | 849 | ||||
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We report on the design and initial testing of the 4th generation Feedback on Nanosecond Timescales (FONT) prototype intra-train beam-based feedback system for beam control and luminosity optimisation at the International Linear Collider (ILC). FONT4 comprises a fast-analogue front-end BPM signal processor, with an FPGA-based digital feedback processor and a fast-risetime kicker-driver amplifier. The system is being designed with a total latency budget (including signal propagation delays) of about 140ns. FONT4 will be deployed at the Accelerator Test Facility (ATF) at KEK, where it will be tested with the electron bunchtrain extracted from the ATF damping ring. The bunches will have a spacing of c. 150ns, chosen to match the ILC design. We report the results of initial beam tests of the system components. We aim to demonstrate feedback, with delay-loop operation, on this ILC-like bunchtrain.
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TUZBPA02 | Crystal Channelling in Accelerators | SPS, collimation, simulation, proton | 945 | ||||
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This presentation will begin with a description of the channelling of charged particles through crystals and the use of the channelling effect in accelerators etc. Results from use of crystals for beam deflection and extraction from synchrotrons in Russia, USA and CERN will also be given. Following this the potential advantage of crystals for collimation in high-energy high-intensity machines will be described.
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Transparencies
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TUPCH056 | A Simpler Method for SR Interferometer Calibration | KEKB, closed-orbit, luminosity, synchrotron | 1136 | ||||
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Previous methods of performing absolute calibration of the SR interferometer used at KEKB (measuring mirror distortion with a pinhole mask, virtual beam broadening via local bumps, physical beam broadening via dispersion bumps) are very time-consuming, and require dedicated machine time to take the necessary data. We report on a new, simpler method we have developed, wherein we create small local bumps at the SR source point and observe the resulting shifts in the phase of the interference fringes. From these data we can calibrate the total magnification of the system, including the effects of mirror distortion. The calibration data can be taken in a very small amount of time (tens of minutes), and in parallel with physics running, without stopping the beam-size measurement system or interfering with its use for luminosity tuning. By taking the calibration data at different beam currents and correlating the magnification at each current with the appropriate interference pattern fit parameters, we can also obtain the parameters needed for real-time mirror distortion correction.
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TUPCH077 | Beam Phase Measurement in a 200 MeV Cyclotron | pick-up, cyclotron, injection, controls | 1187 | ||||
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New phase measuring equipment is being planned for the K 200 variable frequency, separated-sector cyclotron at iThemba LABS near Cape Town. A commercial lock-in amplifier is used to measure the beam phase over the full radial range. Measurements are made at the third and fifth harmonics of the main RF frequency to limit pick-up from the flat-topping and main dees. Computer-generated signals, with phase and amplitude control, at the same harmonics, are used to cancel the signals coupled from the dees to the phase probes. In addition the signals without beam are vectorially subtracted from those with beam to enhance the sensitivity and accuracy. Results of measurements, using these techniques, on existing phase probes in the cyclotron, will be presented.
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TUPCH105 | Performance of a Nanometer Resolution BPM System | alignment, dipole, SLAC, linear-collider | 1256 | ||||
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International Linear Collider (ILC) interaction region beam sizes and component position stability requirements will be as small as a few nanometers. It is important to the ILC design effort to demonstrate that these tolerances can be achieved ideally using beam-based stability measurements. It has been estimated that RF cavity beam position monitors (BPMs) could provide position measurement resolutions of less than one nanometer and could form the basis of the desired beam-based stability measurement. We have developed a high resolution RF cavity BPM system. A triplet of these BPMs has been installed in the extraction line of the KEK Accelerator Test Facility (ATF) for testing with its ultra-low emittance beam. The three BPMs are rigidly mounted inside an alignment frame on variable-length struts which allow movement in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a calibration algorithm which is immune to beam jitter. To date, we have been able to demonstrate a resolution of approximately 20 nm over a dynamic range of ± 20 microns. We report on the progress of these ongoing tests.
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TUPLS012 | Dynamic Stresses in the LHC TCDS Diluter from 7 TeV Beam Loading | simulation, LHC, septum, LEFT | 1511 | ||||
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In the event of an unsynchronised beam abort, the MSD extraction septum of the LHC beam dumping system is protected from damage by the TCDS diluter. The simultaneous constraints of obtaining sufficient beam dilution while ensuring the survival of the TCDS make the design difficult, with high thermally induced dynamic stresses occurring in the material needed to attenuate the particle showers induced by the primary beam impact. In this paper, full 3D simulations are described where the worst-case beam loading has been used to generate the local temperature rise and to follow the resulting time evolution of the mechanical stresses. The results and the accompanying design changes for the TCDS, to provide an adequate performance margin, are detailed.
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TUPLS013 | Protection of the LHC against Unsynchronised Beam Aborts | LHC, kicker, collimation, monitoring | 1514 | ||||
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An unsynchronised beam abort in the LHC could cause major damage to other downstream accelerator components, in particular the extraction septum magnets, the experimental low-beta triplet magnet apertures and the tertiary collimators. Although the LHC beam dumping system includes design features to minimise their frequency, such unsynchronised aborts can arise from several sources and cannot be excluded. A system of protection devices comprising fixed and moveable passive diluters and collimators will be built to safely protect the downstream LHC aperture from the mis-directed bunches in case of such a failure. The sources of unsynchronised abort events are described, together with the requirements and design of the protection devices and their expected performance. The accompanying operational requirements and envisaged solutions are discussed, in particular the problem of ensuring the local orbit at the protection devices.
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TUPLS015 | Calibration Measurements of the LHC Beam Dumping System Extraction Kicker Magnets | LHC, kicker, dumping, CERN | 1520 | ||||
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The LHC beam dumping system must protect the LHC machine from damage by reliably and safely extracting and absorbing the circulating beams when requested. Two sets of 15 extraction kicker magnets form the main active part of this system. They have been produced, tested and calibrated by measuring the integrated magnetic field and the magnet current at different beam energies. The calibration data have been analysed, and the critical parameters are compared with the specifications. Implications for the configuration, control and operation of the beam dumping system are discussed.
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TUPLS016 | Characterization of Crystals for Steering of Protons through Channelling in Hadronic Accelerators | proton, scattering, lattice, CERN | 1523 | ||||
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Channeling of relativistic particles through a crystal may be useful for many applications in accelerators, and particularly for collimation in hadronic colliders. Efficiency proved to be dependent on the state of the crystal surface and hence on the method used for preparation. We investigated the morphology and structure of the surface of the samples that have been used in accelerators with high efficiency. We found that crystal fabrication by only mechanical methods (dicing, lapping, and others) leads to a superficial damaged layer, which is correlated to performance limitation in accelerators. A planar chemical etching was studied and applied in order to remove the superficial damaged layer. RBS analysis with low-energy protons highlighted better crystal perfection at surface, as a result of the etching. Finally, measurement with 70-GeV protons at IHEP demonstrated a superior performance of the chemically cleaned crystals with respect to conventional samples. A protocol for preparation and characterization of crystal for channelling has been developed, which may be of interest for reliable operation with crystals in accelerators.
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TUPLS017 | Optics Study for a Possible Crystal-based Collimation System for the LHC | LHC, collimation, injection, proton | 1526 | ||||
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The use of bent crystals as primary collimators has been long proposed as an option to improve the cleaning efficiency of the LHC betatron and momentum collimation systems. These systems are presently based on two-stage collimation with amorphous scatterers and absorbers. Crystals are expected to help by channeling and extracting the halo particles with large angles, resulting in higher cleaning efficiency. Independent of ongoing studies for crystal qualifications (not reported here), it is important to understand the required deflection angles and the possible locations of absorbers for the LHC layout. Optics studies have been performed in order to specify the required angles for various LHC beam energies and possible locations of absorbers for the deflected halo beam. A possible layout for crystal-assisted collimation at the LHC is discussed, aiming for a solution which would not change the LHC layout but would make use of the existing collimator location.
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TUPLS027 | A Non-scaling FFAG for Radioactive Beams Acceleration (RIA) | acceleration, lattice, injection, RIA | 1547 | ||||
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One of the most expensive components of proposals to accelerate heavy radioactive beams is the superconducting linac. This is an attempt to design a non-scaling Fixed-Field Alternating-Gradient (FFAG) lattice to allow acceleration of heavy radioactive beams in a short time period with an acceptance in momentum of ±50%. As it had been previously reported the non-scaling FFAG has very small orbit offsets, very strong focusing, and large momentum acceptance. The lattice with small combined function magnets would provide substantial savings in the cost of the RF.
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TUPLS075 | Design of the Flat-top Acceleration Cavity for the LNS Superconducting Cyclotron | resonance, acceleration, cyclotron, simulation | 1669 | ||||
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A 3rd harmonic Flat-top acceleration system for the K800 Superconducting Cyclotron of the Laboratori Nazionali del Sud (LNS) was designed to reduce the energy spread of the accelerated particles and to improve the beam quality and the extraction efficiency. The Flat-top effect is realized by the superposition of the 3rd harmonic to the fundamental acceleration frequency. The 3rd harmonic frequency is produced by an additional resonator, capacitively coupled to the K 800 cavities. The Flat-top cavity was designed with the 3D electromagnetic codes Ansoft HFSS and CST MicroWaveStudio.
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TUPLS076 | Beam Extraction of 150 MeV FFAG | septum, kicker, power-supply, KEK | 1672 | ||||
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A beam extraction from FFAG accelerator was performed for the first time at KEK 150MeV proton FFAG synchrotron. The purpose of 150MeV FFAG project is to establish a working prototype for various applications. The beam extraction is thus one of important goals. The extraction is based on fast extraction methode using kicker and pulse septum working at 100Hz. A rapid cycling is also our focus to take advantages of FFAG accelerator. Beam extraction experiment was successful under 100Hz operating. The details of experiment will be presented in this paper.
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TUPLS078 | Design Studies of the Compact Superconducting Cyclotron for Hadron Therapy | cyclotron, ion, injection, simulation | 1678 | ||||
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An overview of the current status of the design of the compact superconducting isochronous cyclotron C400 able to deliver ion beams with a charge to mass ratio of 0.5 is given. This cyclotron is based on the design of the current PT (proton therapy) C230 cyclotron and will be used for radiotherapy with proton, helium or carbon ions. 12C6+ and 4He2+ ions will be accelerated to 400 MeV/u energy and extracted by electrostatic deflector, H2+ ions will be accelerated to the energy 260MeV and extracted by stripping. Computer modeling results on the axial injection system, magnetic system, inflector and center design are given. Results of simulations of the ion beam injection, acceleration and extraction are presented.
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TUPLS079 | Hadron Cancer Therapy Complex Employing Non-scaling FFAG Accelerator and Fixed Field Gantry Design | acceleration, kicker, proton, resonance | 1681 | ||||
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Non-scaling FFAG rings for cancer hadron therapy offer reduced physical aperture and large dynamic aperture as compared with scaling FFAGs. The variation of tune with energy implies the crossing of resonances during acceleration. Our design avoids intrinsic resonances, although imperfection resonances must still be crossed. We consider a system of three non-scaling FFAG rings for cancer therapy with 250 MeV protons and 400 MeV/u carbon ions. Hadrons are accelerated in a common RFQ and linear accelerator, and injected into the FFAG rings at v/c=0.1128. The H+/C6+ ions are accelerated in the two smaller/larger rings to 31 and 250 MeV/52.5 and 400 MeV/u kinetic energy, respectively. The lattices consist of symmetrical triplet cells with a straight section for RF cavities. The gantry with similar triplet cells accepts the whole required momentum range at fixed field. This unique design uses either High Temperature super-conductors or super-conducting magnets reducing gantry size and weight. Elements with a variable field at the beginning and at the end set the extracted beam at the correct position for the specific energy and adapt the beam to specific requirements during treatment.
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TUPLS092 | Implementations on the RF Charge Breeder Device BRIC with Test Measurements | ion, MCP, electron, simulation | 1717 | ||||
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The Radioactive Ion Beam (RIB) production with ISOL technique should require a charge breeder device to increase the ion acceleration efficiency and reduce greatly the production cost. The "charge state breeder" BRIC (BReeding Ion Charge) is based on an EBIS source and it is designed to accept RIB with charge state +1 and increase their charge state up to +n. BRIC has been developed at the INFN section of Bari (Italy) during these last 3 years with very limited funds and it has been assembled at the LNL (Italy) laboratory. BRIC could be considered as a solution for the charge state breeder of the SPES project under study also at the LNL. The new feature of BRIC, with respect to the classical EBIS, is given by the insertion, in the ion drift chamber, of a Radio Frequency (RF) - Quadrupole aiming to filtering the unwanted masses and then making a more efficient containment of the wanted ions. The RF test measurements seem confirm, as foreseen by simulation results* that a selective containment can be obtained. Most accurate measurements, however, are needed and for that implementations of the system have been carried out.
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*V. Variale and M. Claudione. "BRICTEST: a code for charge breeding simulations in RF quadrupolar field", NIM in Phys. res. A 543 (2005) 403-414. |
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TUPLS096 | Strongly Focused He+ Beam Source for Alpha Particle Measurement at ITER | plasma, ion, diagnostics, ion-source | 1726 | ||||
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A He+ beam source for He0 beam probe for measurement of fusion produced alphas due to D-T nuclear reaction in a thermonuclear fusion plasma has been designed and constructed. The ion source consists of a 300 mm diameter and 280 mm length plasma chamber and a beam extraction system which has three concaved electrodes. Helium plasma is confined by line cusp magnetic fields produced by Sm-Co permanent magnets. The magnetic field strength near the extraction region is designed to be less than 20 gauss. Through the 100 mm diameter extraction area of the concaved electrodes 300 beamlets are formed with apertures of 4 mm. The focal length of the concaved electrodes is designed to be 750 mm. The beam quality of the extracted He+ beam will be measured by several beam diagnostic apparatuses. The total beam current, the beam profile and the beam emittance will be measured to design a proper alkali metal vapor cell for a He- beam production by a double charge exchange process and a beam transport line to the post accelerator up to MeV region. In the article, the details of the ion source and the beam diagnostic system will be described.
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TUPLS103 | Further Development of a Low Inductance Metal Vapor Vacuum Arc (LIZ-MeVVA) Ion Source | plasma, ion, vacuum, electron | 1738 | ||||
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A Low Impedance Z-Discharge Metal Vapor Vacuum Arc (LIZ-MeV) ion source* is being explored as an alternate pre-injector for the Brookhaven Relativistic Heavy Ion Collider (RHIC). With the vacuum arc operating at tens of kiloamperes and an aluminum electrode, LIZ-MeV has been run in two regimes: an LC dominated "ringing" arc of period 4.1 microseconds, which decays after about 6 cycles, and a 1-3 microsecond wide "pulsed" arc, where a small series resistance has been added to critically damp ringing. Metal ions are extracted from the plasma using a two-grid system with a triggered, variable-delay voltage of up to 10 kV. Time-of-Flight (TOF) measurements are taken using a Faraday cup located at the end of a 15-76 cm drift tube. TOF measurements from both arc regimes have been obtained suggesting generation of about a billion ions per pulse of charge states +1 and +2, and occasionally +3 states. TOF results are compared with simple theoretical models.
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*B. M. Johnson, et al. Two approaches to electron beam enhancement of the metal vapor vacuum arc ion source. Laser and Particle Beams 21, 103 (2003). |
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TUPLS110 | Measurement of the Extraction Kicker System in J-PARC RCS | kicker, vacuum, LEFT, proton | 1759 | ||||
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Kicker magnet system in the J-PARC RCS is now under construction at JAEA (Japan Atomic Energy Agency). Their role in RCS is to kick the accelerated 3 GeV proton beam to the following extraction line at a repetition rate of 25 Hz. There are three kinds of kicker magnets (S, M, L), distinguished by the difference in the size of their apertures. The specification of 2 % is required on the magnetic field in terms of homogeneity in time and space from the beam optical point of view. The required flatness of the temporal uniformity was accomplished by superposing the waveforms of the two kicker magnet*. The required specification to the special uniformity is also very severe to achieve because our kicker magnet is designed with a large aperture in order to accept a maximum beam power of 1 MW. We established the search coil as a detector and 3-axes stage to perform magnetic field mapping. In order to reduce the signal noises and detect the stable output signals, matching register and integrated circuit were carefully selected. The 3-axes stage was precisely aligned. The distribution of the magnetic field (By) and integrated BL were systematically measured for the three types of kickers.
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*J. Kamiya et al. Magnetic field measurement of the extraction kicker magnet in J-PARC RCS, submitted for publication to the proceedings of the 19th International Conference on Magnet Technology. |
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TUPLS111 | Experimental Results of the Shift Bump Magnet in the J-PARC 3-GeV RCS | injection, power-supply, linac, controls | 1762 | ||||
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The shift bump magnet produces a fixed main bump orbit to merge the injection beam into the circulating beam. In order to control the injection beam for the short injection time (500 microseconds) with sufficient accuracy, the shift bump magnet needs a wide uniform magnetic field and the high speed exciting pattern of the high current. The magnetic field design and the structural analysis of the shift bump magnets have been performed using three-dimensional electromagnetic analysis code and mechanical analysis code, respectively. The magnetic field distributions were measured with a long search coil, thus giving a BL product over a magnet gap area. The temperature distributions at the various points of the magnet were measured by thermocouples over 24 hours till they saturated. General trend of these measurements agrees well with calculations.
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TUPLS112 | Present Status of Injection and Extraction System of 3 GeV RCS at J-PARC | injection, proton, vacuum, emittance | 1765 | ||||
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The injection and extraction system for 3GeV RCS (Rapid Cycling Synchrotron) at J-PARC (Japan Proton Accelerator Research Complex) have many challenging issues, in order to realize MW beam in the RCS ring. The system is consisted in 3 parts, such as the injection line, the dump line, and the extraction line. And they are constructed from many kinds of components, such as DC and pulse magnets, a charge exchange system, beam monitors, titanium and ceramic vacuum chamber, a beam dump, and so on. Up to now, final designs are accomplished and developments and experiments of some components are carried out. In this presentation, summary of the injection and extraction system, recent status of developments, and beam commissioning scheme for beam injection and extraction are introduced.
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TUPLS113 | Designs of Septum Magnet at 3 GeV RCS in J-PARC | septum, vacuum, injection, shielding | 1768 | ||||
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3 GeV RCS (Rapid Cycling Synchrotron) at J-PARC (Japan Proton Accelerator Research Complex) consists in many kinds of septum magnets. There are two septum magnets to inject the beam into the ring, three septum magnets to extract the beam for the users, and two septum magnets to dump the beam which can not be exchanged its charge at the first foil. In order to reduce the magnetic leakage field from the septum magnets at the beam orbit in the ring, the silicon steel sheets are set at the outside of the septum magnets for the magnetic shields. However sufficient spaces to set the thick magnetic shields are not securable at the divergent duct areas. Therefore the vacuum chambers are made by the magnetic stainless steel and the leakage fields in the chambers can be reduced. As results of the 3D field calculations by TOSCA, the magnetic leakage field can be suppressed to a few Gauss or less.
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TUPLS114 | An Improvement of Matching Circuit of RF Kicker Electrodes | controls, feedback, kicker, impedance | 1771 | ||||
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Beam extraction system at accelerator of The Wakasa Wan Energy Research Center employs RF knockout technology. Narrow band RF noise is applied to the transverse kicker electrodes to increase betatron amplitude of the beam. Recently some improvements of the beam extraction system are introduced: To improve the shape of the spill, a feedback control of noise amplitude is introduced. The feedback control system works as an attenuator, therefore it is necessary to enhance the noise amplitude of the kicker electrodes to obtain agreeable effect on the spill shape. In order to obtain a higher voltage, we revamp the matching circuit at the electrodes. By introducing the resonating characteristic at the matching circuit, we obtained 3 times more amplitude at the electrodes. General shape of the spill is improved by this work, and extraction efficiency at a real operating condition is also improved.
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TUPLS116 | Extraction System Design for the CSNS/RCS | kicker, septum, shielding, lattice | 1777 | ||||
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The CSNS extraction system takes use one of the four dispersion-free straight sections. Five vertical kickers and one Lambertson septum magnet are used for the one-turn extraction. The rise time of less 250 ns and the total kicking angle of 20 mrad are required for the kickers that are grouped into two tanks. The design for the kicker magnets and the PFN is also given. To reduce the low beam loss in the extraction channels due to large halo emittance, large apertures are used for both the kickers and septum. Stray magnetic field inside and at the two ends of the circulating path of the Lambertson magnet and its effect to the beam has been studied.
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TUPLS122 | Implementation of the Proposed Multiturn Extraction at the CERN Proton Synchrotron | kicker, septum, beam-losses, SPS | 1789 | ||||
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Following the positive results of the three-year measurement campaign at the CERN Proton Synchrotron concerning beam splitting with stable islands in the transverse phase space, the study of a possible implementation of the proposed multi-turn extraction was undertaken. The novel approach would allow a substantial reduction of beam losses, with respect to the present scheme, when delivering the high-intensity proton beams required for the planned CERN Neutrino to Gran Sasso Project. Major modifications to the ring layout are foreseen, such as a new design of the extraction bumps including also the installation of three additional kickers to create a closed-bump over the five turns used to extract the split beam. The ring aperture was reviewed and improvements are proposed to reduce possible beam losses between beam splitting and extraction. The goal consists of implementing the proposed changes by the end of the 2007/2008 PS shutdown and to commission the novel extraction during the 2008 physics run.
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TUPLS125 | Spin Transport from AGS to RHIC with Two Partial Snakes in AGS | AGS, RHIC, injection, dipole | 1795 | ||||
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The stable spin direction in the RHIC rings is vertical. With one or two strong helical Siberian snakes in the AGS, the stable spin direction at extraction is not vertical. Interleaved vertical and horizontal bends in the transport line between AGS and the RHIC rings also tend to tip the spin away from the vertical. In order to preserve polarization in RHIC, we examine several options to improve the matching of the stable spin direction during beam transfer from the AGS to each of the RHIC rings. While the matching is not perfect, the most economical method appears to be a lowering of the injection energy by one unit of G*gamma to 45.5.
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WEOBPA03 | 1.8 MW Upgrade of the PSI Proton Facility | cyclotron, target, simulation, space-charge | 1879 | ||||
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The PSI proton accelerator delivers currently a 590 MeV beam with an intensity of 2 mA. The upgrade programme aiming at boosting the beam power from 1.2 to 1.8 MW includes the ongoing installation of new bunchers in the transfer lines to the injector cyclotron and between injector and ring cyclotron, the replacement of the Al-cavities of the ring cyclotron by Cu-cavities operated at 1 MV, and the design and future installation of additional accelerating cavities in the injector cyclotron. Simulation studies are under way to improve our understanding of the space charge effects at the different stages of acceleration. The present status of the project will be presented.
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Transparencies
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WEPCH029 | Injection and Extraction Orbit of the J-PARC Main Ring | injection, beam-losses, kicker, quadrupole | 1987 | ||||
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The J-PARC main ring (MR) accelerates a high intensity proton beam and deliver to the neutrino experimental hall by the fast extraction and to the hadron experimental facility by the slow extraction. The beam from the rapid cycle synchrotron (RCS) is injected by the bunch to bucket transfer into the MR. The MR has two beam dump lines, the first one is used to dump the beam at injection energy and the second one can be used to abort accelerated beam. The beam loss at the injection and extraction is one of the critical issue for high intensity proton accelerators. We report designed injection and extraction orbits and discuss about the beam apertures and the beam loss.
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WEPCH033 | Single Particle Beam Dynamics Design of CSNS/RCS | dipole, lattice, collimation, injection | 1996 | ||||
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Rapid Cycling Synchrotron (RCS) is a key component of Beijing Spallation Neutron Source (BSNS). It accumulates and accelerates protons to design energy of 1.6 GeV and extracts high energy beam to the target. As a high beam density and high beam power machine, low beam loss is also a basic requirement. An optimal lattice design is essential for the cost and the future operation. The lattice design of BSNS is presented, and the related dynamics issues are discussed. The injection/extraction scheme and the beam collimation system design are introduced.
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WEPCH040 | Further Development of Irradiation Field Forming Systems of Industrial Electron Accelerators | electron, target, vacuum, radiation | 2005 | ||||
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Electron beam irradiation field forming systems where accelerated electron beam is scanned in a constant field of the elongated bending magnets were developed in our institute more than 15 years ago and they have a number of advantages in comparison with traditional ones. Since than they have been applied in two accelerators with energies 300 and 400 keV; version of the similar system with two electromagnets for two-side irradiation of flexible materials in a number of 750 keV high voltage accelerators ("Electron-10") successfully operating now in several industrial lines. Systems of forming of electron beam irradiation field based on the same principle have been used in several projects, some of them are already put into operation. Electron optic characteristics of such systems and their various modifications as well as aspects of their possible usage are discussed in the paper.
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WEPCH082 | Simulation of Ions Acceleration and Extraction in Cyclotron C400 | resonance, ion, cyclotron, acceleration | 2113 | ||||
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The Belgian company IBA, together with scientists of the JINR in Dubna is designing a superconducting isochronous cyclotron for therapy by Carbon beams. The new cyclotron C400 has to deliver carbon ions with energy 400 MeV/amu and protons with energy close to 250 MeV. The cyclotron has a compact type superconducting magnet, with a pole radius of 187 cm. The axial focusing is provided by four sectors, with a spiral angle increasing to a maximum value close to 70° at maximum energy. With this design, an axial betatron frequency is maintained during most of the acceleration. The beam acceleration is provided by two spiral dees located in opposite valleys. The dee voltage increases from 100 kV at the center to 200 kV at extraction. The paper presents the analysis of the beam acceleration in the proposed new cyclotron. During the acceleration, several resonance lines are crossed, but the paper demonstrates that this resonance crossing is done without damaging the beam properties. Extraction of the Carbon ions is done by an electrostatic deflector, followed by magnetic correctors. Protons are extracted at lower energy by stripping 2H+1 ions.
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WEPCH086 | Adiabatic Theory of Slow Extraction of Particles from a Synchrotron | resonance, synchrotron, betatron, heavy-ion | 2119 | ||||
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An analytical approach is developed to describe the process of slow extraction of particles from a synchrotron based on adiabatic crossing of the betatron resonance of the third order. An exact expression for the phase integral is found to analyze the conditions of oscillation amplitude growth near the resonance band. It allows one to directly define the interval of adiabatic motion from the start of decreasing the resonant tune to the beginning of fast increase of the oscillation amplitude. The interval distribution function is constructed for the cases of zero momentum spread and zero machine chromaticity as well as for the general case, taking into account non-zero momentum spread, non-zero chromaticity and synchrotron oscillations. Some numeric calculations of the time dependence of the extracted particle current are presented. It is shown that the momentum spread in the extracted beam can be minimized with the use of additional RF acceleration of particles during the slow extraction procedure.
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WEPCH110 | Calculation of Wake Potentials in General 3D Structures | impedance, vacuum, radiation, controls | 2170 | ||||
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The wake potential is defined as an integration along an axis of a structure. It includes the infinitely long beam pipe regions and in case of numerical evaluation leads to pipe wake artefacts. If the structure is cavity like one can position the integration path on the pipe wall and only the integration over the cavity gap remains. In case of axis-symmetric protruding structures it was proposed by O. Napoly et al. to deform the path such that the integration in the pipe regions is again on the wall. The present paper generalizes this method of path deformation to 3D structures with incoming and outgoing beam pipes. Its usefulness is verified with the code GdfidL and no artifacts were observed.
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WEPCH126 | Issues in Modelling of Negative Ion Extraction | ion, plasma, electron, scattering | 2218 | ||||
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In the context of negative ion sources proposed for neutral beam injectors for tokamaks, halo of the extracted beam is typically large (about 10 %) and optimum shape of the multiaperture extraction electrode is a matter of research. Present designs range from an aperture angle of 45 degree (low current, convergent beam) to 90 degrees (flat electrode, high current, large divergence and halo). Two major difficulties of the beam extraction modelling are here discussed. First, the generation processes of negative ion show some shortcomings: volume production seems low; wall production is large, but ions have wrong directions and/or large nonuniformity in current density; elastic scattering of wall generated ions into the extraction direction must compete with mutual neutralization. Second, the plasma sheath charge has to be negative on the extraction hole surface and positive on the nearby wall surface, which enhances beam aberration near hole edge. After discussing limitation of existing codes and model, result from an ad hoc code are discussed. Also 2D equation for the selfconsistent electrostatic field can be written and implemented into a multiphysics general purpose program.
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WEPCH127 | Analysis of Radiative Effects in the Electron Emission from the Photocathode and in the Acceleration inside the RF Cavity of a Photoinjector using the 3D Numerical Code RETAR | electron, radiation, acceleration, brightness | 2221 | ||||
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The three-dimensional fully relativistic and self-consistent code RETAR has been developed to model the dynamics of high-brightness electron beams and in particular to assess the importance of the retarded radiative part of the emitted electromagnetic fields in all conditions where the electrons experience strong accelerations. In this analysis we evaluate the radiative energy losses in the electron emission process from the photocathode of an injector, during the successive acceleration of the electron beam in the RF cavity and the focalization due to the magnetic field of the solenoid, taking also into account the e.m. field of the laser illuminating the cathode. The analysis is specifically carried out with parameters of importance in the framework of the SPARC and PLASMONX projects.
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WEPCH134 | Development of Code for Simulation of Acceleration of Ions from Internal Source to End of Extraction System in Cyclotrons and Preliminary Design Study of 8MeV Cyclotron for Production of Radioisotopes | cyclotron, acceleration, simulation, ion | 2236 | ||||
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From the users' point of view modern cyclotrons must be compact, energy-saving, low-radiation and very reliable facilities. To provide all these characteristics, a very detailed design study of all systems of an accelerator under development is required. Thus, particle tracking from the "beginning" to the "end" in modern cyclotrons with small gaps in the main acceleration region and with efficient extraction systems becomes a very important task for designers. Codes for beam dynamics simulation at the center, main acceleration region and through the extraction system of the cyclotron have been developed. It is possible to monitor all main beam parameters at the different stages of acceleration, radial, axial and phase motion of the beam and the energy increase. During tracking particles through the extraction system it is possible to calculate rms envelopes of radial and vertical motion of the beam and beam losses at the aperture of the extraction system elements. A preliminary design of a compact 8-MeV proton cyclotron was studied using created codes. The accelerator is supposed to have a four sector compact magnet system with the pole 64 cm in diameter.
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WEPCH154 | SPS Access System Upgrade | SPS, LHC, controls, injection | 2287 | ||||
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The present SPS access system is not entirely compatible with the formal requirements of the French Radioprotection Authorities, and a project has been launched to remedy this situation. The upgrade project is split into three phases that will be implemented, in the present planning, in the shutdowns 2006, 2007 and after the first physics run of the LHC, respectively. This paper presents the results of the safety study, the upgrade strategy and the architecture of the upgraded system.
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WEPCH155 | Tune-stabilized Linear-field FFAG for Carbon Therapy | acceleration, injection, focusing, multipole | 2290 | ||||
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The simplicity, smaller aperture, and reduced ring size associated with linear-field, nonscaling FFAGs have made them attractive to investigate for a broad range of applications. Significant progress has recently been made towards understanding and modeling this new type of accelerator. The merits, drawbacks and challenges of the linear-field FFAG are discussed here, in particular its suitability for proton and carbon cancer therapy as compared with conventional synchrotrons and cyclotrons. Specifically, tune stabilization and dynamic aperture, a problem with both scaling and non-scaling FFAGs, will be addressed in detail.
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WEPCH157 | Design and Beam Dynamics Simulation for the Ion-injector of the Austrian Hadron Therapy Accelerator | ion, simulation, proton, synchrotron | 2296 | ||||
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MedAustron is an initiative for the construction of the Austrian Hadron Therapy Centre. In 2004 the design study was presented. The basic design consists of two ion sources, an ion-injector, a synchrotron and a beam transfer line with five possible beam exits. The synchrotron is based on the proton ion medical machine study (PIMMS) design with some modifications. The injector is based on the GSI design of the Heidelberg ion therapy cancer accelerator with the original radio frequency quadrupole and IH-Linac. Modifications have been done in the design of the low energy beam transport and the medium energy beam transport lines. The impact of these modifications has been investigated, and several other beam scenarios have bean simulated with different simulation codes.
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WEPCH160 | A Novel Proton and Light Ion Synchrotron for Particle Therapy | synchrotron, septum, dipole, injection | 2305 | ||||
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A compact and simple synchrotron for a cancer particle therapy system has been designed and is presently under construction. A lattice with six regular superperiods, twelve dipole and twelve quadrupole magnets, is used. The optimized lattice configuration, including the design of injection and extraction systems, provides large transverse phase space acceptance with minimum magnet apertures. The result is a synchrotron for PT with light magnets (5t dipoles), low values of peak power for pulsed operation and minimum dc power consumption. In addition, industrial production principles are used, keeping ease of construction, installation, and operation in mind. The beam, injected at 7 MeV/amu, can be accelerated to the maximum magnetic rigidity of 6.6 Tm in less than 1 s. A beam of 48-250 MeV protons and 88-430 MeV/u carbon ions can be slowly extracted during up to 10s. The intensity for protons and carbon ions will be well beyond the needs of scanning beam applications. The design and performance specifications of the synchrotron will be described in detail.
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WEPCH167 | Study of Scatterer Method to Compensate Asymmetric Distribution of Slowly Extracted Beam at HIMAC Synchrotron | scattering, simulation, emittance, synchrotron | 2322 | ||||
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In the medical use of the ion beam, the following characteristics of the beam are preferred: 1) Symmetric Gaussian beam profile is convenient for the scanning irradiation. 2) In the rotating gantry system, the symmetric beam condition can realize no-correlation between the beam profiles and the rotation angles of the gantry. However, the slowly extracted beam has asymmetric distribution in the phase-space and a difference between the horizontal emittance and vertical one. Thus, we have proposed the thin scatterer method to compensate the phase-space distribution of the slowly extracted beam, although the emittance is enlarged by scattering. As a result of particle tracking and experiment, it was verified that the asymmetric distribution was compensated by very small scattering angle. It was also simulated that this scatterer method can realize the symmetric beam condition for the rotating gantry. In this paper, these results of asymmetry compensation for the slow-extraction at HIMAC is presented.
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WEPCH168 | Development toward Turn-key Beam Delivery for Therapeutic Operation at HIMAC | ion, heavy-ion, quadrupole, emittance | 2325 | ||||
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Since 1994, more than 2500 cancer patients have been treated by carbon ion beam at HIMAC. To increase the number of patients per day, we have studied the reproducibility of the beam quality, such as the position, profile and intensity, during the operation. For this purpose, the accelerator needs high reproducibility to minimize the beam tuning time with more flexible scheme. Further, the irradiation system and the accelerator need to ensure dose uniformity. As a result of this study, it was found that a slight change of the magnetic field in the transport line would not affect the beam quality. However, a slight change of the horizontal tune strongly affects the beam quality because of a resonant slow-extraction. In this paper, we report about our investigation and present result of the development.
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WEPCH170 | Development of Intensity Control System with RF-knockout Extraction at the HIMAC Synchrotron | controls, synchrotron, ion, heavy-ion | 2331 | ||||
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We have developed a dynamic intensity control system toward scanning irradiation at the HIMAC Synchrotron. In this system, for controlling the spill structure and intensities of the beams extracted from the synchrotron, the amplitude of the RF-knockout is controlled with the response of 10 kHz. Its amplitude modulation (AM) function is generated based on an analytical one-dimensional model of the RF-knockout slow-extraction. In this paper, we describe the system for controlling amplitude modulation including feedback and the experimental result.
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WEPCH181 | Ion Implantation Via Laser Ion Source | ion, laser, plasma, target | 2355 | ||||
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We report on the development of a new implantation technique via laser ion source. By applying a high voltage on the accelerating gap, this compact device was able to accelerate towards a substrate ions from ablation plasma. The occurrence of arcs during the extraction phase was a major problem to overcome. A pulsed KrF laser was utilized to produce plasma by ablation of solid targets. Radiation wavelength and pulse duration were 248 nm and 20 ns, respectively. The laser beam, 70 mJ per pulse, was focused onto different targets in a spot of about 1 mm2 in surface, obtaining an irradiance value of about 3.5 x 108 W/cm2. The implanted samples were characterized by energy dispersive x-ray spectroscopy, Rutherford backscattering spectrometry and x-ray photoelectron spectrometry. Implantations of Al, Cu and Ge on Si substrates were carried out up to 80 nm in depth, operating at 40 kV acceleration voltage. Ion dose was estimated by Faraday cup diagnostics. It was of the order of 1010 ions/cm2 per pulse.
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WEPCH191 | The Design and Manufacture of a 300 keV Heavy Ion Implanter for Surface Modification of Materials | ion, ion-source, acceleration, target | 2382 | ||||
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A 300keV ion implanter has been designed for studies of surface modification of several materials by ion beam. The purpose of design is domestic development of the basic technology for the high energy ion implanter. The main point of design is production, acceleration and transportation of high nitrogen ion beam current up to 5mA and ion energy up to 300keV. 300keV ion implanter consists of Duo-PIGatron ion source, einzel lens, mass separation magnet, acceleration tube, magnetic quadrupole doublet, electrostatic scanner and target. Beam optics design carried out where space charge effect in the acceleration tube and second order aberrations in the mass separation magnet were considered. The mass numbers range from 1 to 140 and the resolving power M/ΔM is 131. Implanter control system includes fiber optics links for the monitoring and control of the ion source parameters in the high voltage zone and computer system for the characterization of the ion beam and whole control of an implantation process.
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WEPLS002 | Design and Expected Performance of the Muon Beamline for the Muon Ionisation Cooling Experiment | target, emittance, proton, simulation | 2397 | ||||
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It is proposed to install a Muon Ionisation Cooling Experiment (MICE) at the ISIS facility, at Rutherford Appleton Laboratory (RAL). This experiment will be the first demonstration of ionisation cooling as a means to reduce the large transverse emittance of the muon beam, produced during the early stages of a Neutrino Factory. In order to permit a realistic demonstration of cooling, a beam of muons must be produced, possessing particular qualities, notably in emittance and momenta. This paper describes the current design for the muon beamline, outlining issues particular to the needs of the MICE experiment, and discusses its expected performance.
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WEPLS077 | Considerations on the Design of the Bending Magnet for Beam Extraction System of PEFP | proton, dipole, focusing, target | 2556 | ||||
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The PEFP is designed to have two beam extraction lines at the 20 MeV end and 100MeV end for beam utilization. So, the bending magnet to extract the beam from the beam line is located among the MEBT. This implies that there is a long drift space between the focusing structures, while, from the beam dynamics study, it is recommended to make the drift space shorter. In this study, we design and compare some bending magnets to satisfy the beam dynamics requirements.
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WEPLS078 | Design Study of the 30 MeV Cyclotron Magnet | cyclotron, acceleration, proton, injection | 2559 | ||||
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Korea Institute of RAdiological & Medical Sciences (KIRAMS) has been developing a 30 MeV cyclotron that is planned to be installed at Advanced Radiation Technology Institute, Jeongeup in late 2006. The AVF (Azimuthally Varying Field) magnet of the cyclotron was designed to produce 15-30 MeV proton beam with movable stripper foil. Four directions of extractions are available with two switching magnets. The overall shape of the magnet is cylindrical. The magnet has three kinds of holes for beam injection, vacuum pumps and RF system. The valley and hill gap ratio is about 20 for higher axial focusing. The designed magnet model and its magnetic properties of the KIRAMS-30 are presented.
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WEPLS081 | Modifications to the SPS LSS6 Septa for LHC and the SPS Septa Diluters | LHC, SPS, septum, proton | 2565 | ||||
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The Large Hadron Collider required the modification of the existing extraction channel in the long straight section (LSS) 6 of the CERN Super Proton Synchrotron (SPS), including the suppression of the electrostatic wire septa. The newly set up fast extraction will be used to transfer protons at 450 GeV/c as well as ions via the 2.9 km long transfer line TI 2 to Ring 1 of the LHC. The girder of the existing SPS DC septa was modified to accommodate a new septum protection element. Changes were also applied to the septum diluter in the fast extraction channel in SPS LSS4, leading to the other LHC ring and the CNGS facility. The requirements and the layout of the new LSS6 extraction channel will be described including a discussion of the design and performance of the installed septum diluters.
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WEPLS082 | The Septa for LEIR Extraction and PS Injection | septum, vacuum, ion, injection | 2568 | ||||
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The Low Energy Ion Ring (LEIR) is part of the CERN LHC injector chain for ions. The LEIR extraction uses a pulsed magnetic septum, clamped around a metallic vacuum chamber. Apart from separating the ultra high vacuum in the LEIR ring from the less good vacuum in the transfer line to the PS this chamber also serves as magnetic screen and retains the septum conductor in place. The PS ion injection septum consists of a pulsed laminated magnet under vacuum, featuring a single-turn water cooled coil and a remote positioning system. The design, the construction and the commissioning of both septa are described.
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WEPLS092 | Computer Modeling of Magnetic System for C400 Superconducting Cyclotron | cyclotron, simulation, injection, focusing | 2589 | ||||
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The superconducting cyclotron (C400) is designed at IBA (Belgium) able to accelerate carbon ions at 400 MeV/nucleon. By computer simulation with 3D TOSCA code, the cyclotron magnetic system principal parameters were estimated (pole radius 187 cm, outer diameter 606 cm, valley depth 60 cm, height 276 cm). The required isochronous magnetic field was shaped with an accuracy of ± 2 mT. Four-fold symmetry and spiralized sectors with elliptical gap (minimal 12 mm at extraction) provide the stable beam acceleration till 15 mm from the pole edge.
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WEPLS129 | Upgrade Scheme for the J-PARC Main Ring Magnet Power Supply | power-supply, KEK, linac, synchrotron | 2679 | ||||
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Japan Proton Accelerator Research Complex (J-PARC) is under construction at the Tokai campus of Japan Atomic Energy Agency (JAEA) as a joint project between KEK and JAEA. The accelerator complex, which is constructed as a 200 MeV linac, a 3 GeV RCS synchrotron, and a main ring in phase I. The main ring magnet power supply is constructing as the energy of 40 GeV in phase I and will upgrade up to 50 GeV in phase II. A large amount of pulse electric power, which is + 115 MW and -55 MW peak-to-peak, is required for 50 GeV operation and this large pulse power will give unallowable disturbances to a power network. In order to compensate the disturbances to allowable level, we need some energy storage system. A SMES system will be one of the promising means for the purposes as well as the fly-wheel system. We will describe some energy storage system and also the increasing of repetition rate without energy storage system.
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WEPLS131 | Programmable Power Supply for Distribution Magnet for 20-MeV PEFP Proton Linac | power-supply, controls, proton, damping | 2682 | ||||
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The distribution magnet is powered by bipolar switching-mode converter that is employed IGBT module and has controlled by a DSP (Digital Signal Process). This power supply is operated at 350A, 5 Hz programmable stair output for beam distribution to 5 beamlines of 20-MeV PEFP proton linac. Various applications for the different power supply are made simple by software. This paper describes the design and test results of the power supply.
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WEPLS136 | Pulsed Magnet Power Supplies for Improved Beam Trajectory Stability at the APS | septum, booster, injection, power-supply | 2697 | ||||
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New power circuit and control electronics have been implemented in the septum power supplies at the Advanced Photon Source (APS). The goal was to meet a low pulse-to-pulse relative amplitude jitter of about ± 5·10-4 for trajectory stability in the booster-to-storage ring transport line. The original power supply design produced a jitter of ± 15e-4, which made injection tuning difficult. The jitter for the two new booster pulsed magnet supplies is now 1.1e-4, as inferred by a beam-based statistical analysis. A common design was made for all of the septum magnet power supplies at the APS. The system, regulation algorithms, the results achieved, and the current regulation stability issues will be discussed.
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WEPLS142 | The Importance of Layout and Configuration Data for Flexibility during Commissioning and Operation of the LHC Machine Protection Systems | LHC, controls, superconducting-magnet, CERN | 2712 | ||||
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Due to the large stored energies in both magnets and particle beams, the LHC requires a large inventory of machine protection systems, as e.g. powering interlock systems, based on a series of distributed industrial controllers for the protection of the more than 10,000 normal and superconducting magnets. Such systems are required to be at the same time fast, reliable and secure but also flexible and configurable to allow for automated commissioning, remote monitoring and optimization during later operation. Based on the generic hardware architecture of the LHC machine protection systems presented at EPAC 2002 and ICALEPS 2003, the use of configuration data for protection systems in view of the required reliability and safety is discussed. To achieve the very high level of reliability, it is required to use a coherent description of the layout of the accelerator components and of the associated machine protection architecture and their logical interconnections. Mechanisms to guarantee coherency of data and repositories and secure configuration of safety critical systems are presented. This paper focuses on the first system being commissioned, the complex magnet powering system.
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THPCH054 | SIMPSONS with Wake Field Effects | kicker, injection, impedance, emittance | 2910 | ||||
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Simpsons, which is originally developed by S. Machida, is the program which calculates the space charge effect to the beam in the ring. The wake field effect to the beam is also installed in this program, because the emittance growth not only due to the space charge effect, but also due to the wake field effect is the important issue. The results of the simulation in J-PARC case are also represented.
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THPCH059 | Kicker Impedance Measurements for the Future Multi-turn Extraction of the CERN Proton Synchrotron | kicker, impedance, LEFT, resonance | 2919 | ||||
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In the context of the novel multi-turn extraction, where charged particles are trapped into stable islands in transverse phase space, the ejection of five beamlets will be performed by means of a set of three new kickers. Before installing them into the machine, a measurement campaign has been launched to evaluate the impedance of such devices. Two measurement techniques were used to try to disentangle the driving and detuning impedances. The first consists in measuring the longitudinal impedance for different transverse offsets using a single displaced wire. The sum of the transverse driving and detuning impedances is then deduced applying Panofsky-Wenzel theorem. The second uses two wires excited in opposite phase and yields the driving transverse impedance only. Finally, the consequences on the beam dynamics are also analyzed.
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THPCH088 | A Possibility of Constant Energy Extraction at the KEK ATF2 | KEK, synchrotron, feedback, kicker | 2994 | ||||
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Beam energy oscillations of the order of 0.02% take place at the KEK ATF. With extractions, the synchrotron oscillation amplitude and phase at the extraction turn randomly fluctuates. The energy jitter causes a position/angle jitter in the Diagnostic section of the Extraction Line. To reduce it, a feed forward energy stabilisation can be used done by extraction of the beam at the turn next to that turn at which the energy passes the equilibrium value. For this, the synchrotron oscillation is measured by a turn-by-turn BPM as a horizontal position oscillation. A fast turn-by-turn processor detects the turn where the oscillation passes zero, and generates an extraction permission signal that triggers the existing ATF Extraction system. Stability improvement by factor of 10 can be obtained even when the extraction is done with uncertainty up to three turns after the trigger.
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THPCH123 | New Control System for Nuclotron Main Power Supplies | controls, power-supply, monitoring, quadrupole | 3089 | ||||
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New control and monitoring system for Nuclotron main power supplies was designed in order to substantially extend functionality of the existing equipment and software. The lattice bending (BM), focusing (QF) and defocusing (QD) magnets are powered by two supplies. The BM magnetic field shape is set by pulse function generator that produces a reference burst (Bo-train) with 0.1 Gs resolution. This train controls pattern analog function generator based on a 18-bit DAC. A real B-train from the reference magnet and corresponding analog function are used for feedback loop. The current magnetic field of BM is used as reference function for the focusing and defocusing magnets. A scaling 16-bit multiplied DAC is used to set required ratio IBM/IQFD during accelerator cycle. A 16-bit data acquisition card provides measurement of all analog signals. Digital I/O boards are applied to set and read status of the power supplies, accompanying subsystems and interlocks. Timing modules provide the trigger pulses both for the system internal needs and for synchronizing of the accelerator subsystems and experimental setups.
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THPCH125 | Inter-laboratory Synchronization for the CNGS Project | CERN, SPS, site, controls | 3092 | ||||
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CERN will start sending a neutrino beam to Gran Sasso National Laboratory in Italy in May 2006. This beam will cover a distance of around 730 km through the crust of the earth from an extraction line in CERN's SPS to dedicated detectors in Gran Sasso. This paper describes the technological choices made to fulfill the specification of inter-laboratory synchronization in the region of 100 ns, as well as some preliminary results. The common time standard is UTC as disseminated by the GPS system, and the techniques are similar to those used by national metrology laboratories for the manufacturing of UTC itself. In addition, real-time messages sent through the Internet allow the detectors in Gran Sasso to go into calibration mode when no beam is being sent. Data concerning the delay and determinism of this international network link is also presented.
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THPCH139 | Development of an Ion Source via Laser Ablation Plasma | ion, plasma, target, laser | 3119 | ||||
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Experimental results on the development of a laser ion source (LIS) are reported. LISs are particularly useful in ion accelerators, ion implanters and devices for electromagnetic isotope separation. A focused UV laser beam (0.1 - 1 GW/cm2 power density) was used to produce a plasma plume from a Cu target. Several aspects were investigated: ion angular distribution, energy distribution, ion extraction and charge loss due to ion recombination. Particular attention was devoted to avoid arcs during the extraction phase; it was accomplished by allowing the proper plasma expansion in a suitable chamber before the extraction gap. Diagnostics on free expanding plasma and extracted ions was carried out mainly by time-of-flight measurements, performed by means of Faraday cups and electrostatic spectrometers. At 18kV acceleration voltage, the ion beam current, measured along a drift tube at 147cm from the target, resulted modulated on ion mass-to-charge ratio and its maximum value was 220uA. The Cu+1 ion bunch charge was estimated to be 4.2nC. Ion implantation tests were successfully performed at high acceleration voltage (several tens kV), by using a simple experimental arrangement.
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THPCH143 | The Fast Extraction Kicker System in SPS LSS6 | kicker, SPS, impedance, LHC | 3125 | ||||
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A new fast extraction has been set up in SPS LSS6 to transfer 450 GeV/c protons as well as ions to Ring 1 of the LHC, via the transfer line TI 2. The system includes four travelling wave kicker magnets, recuperated from earlier installations and upgraded to fit the new application. All four magnets are powered in series, energised by a single PFN generator and terminated by a short circuit. The layout and the modifications to the magnets and the high voltage circuit are described along with the impact of design choices on the performance of the system. Results from laboratory tests and first machine experience are reported on approaches to overcome the effects of the beam induced kicker heating observed earlier, including a beam screen in form of metallic stripes printed directly onto the ferrites and the use of ferrite blocks with high Curie temperature. Prospects for further improvements are briefly discussed.
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THPCH144 | The Upgrading of the TLS Injector Bumper and Septum Power Supplies for Top-up Operation | power-supply, septum, booster, controls | 3128 | ||||
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Due to the inevitable requirement of routine top-up mode operation at TLS (Taiwan Light Source), the reliability of all components in TLS injector has been reevaluated in the past several months. Among all possible subsystems to be reinforced, the bumper and septum power supplies revealed urgent need of upgrading while operated continuously in the user shifts. In this report, the modification of the charging mechanism of the pulsed power supplies is described. The modular feature of the newly built units provides fast replacement capability in case of components failure. The unified specifications for all components have greatly reduced the effort in preparing spare parts. The test results of these units are presented in this report.
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THPCH148 | Tests of a High Voltage Pulser for ILC Damping Ring Kickers | kicker, damping, linac, injection | 3137 | ||||
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The baseline configuration for the International Linear Collider (ILC) damping rings specifies a single 6 km damping ring for electrons and two 6 km rings for positrons. Kicker requirements are determined by the damping ring circumference and the train structure in the main linac. The nominal bunch train parameters in the ILC main linac are trains of 2820 bunches with 308 ns spacing and a train repetition rate of 5 Hz. This means that the pulsers for the damping ring kickers must have rise and fall times suitable for bunch spacings of ~6 ns, must be able to operate with 3.25 Mhz bursts, and must support an average pulse rate of 14.1 kHz. We describe bench and beam tests of a pulser based on fast ionization dynistor technology whose specifications roughly meet these requirements. We then discuss the implications of our results for the ILC damping ring kickers.
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THPCH177 | Design and Construction of the PEFP Timing System for a 20 MeV Proton Beam | proton, power-supply, controls, rfq | 3212 | ||||
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The timing system of the PEFP requires synchronization for the accelerator and for the multipurpose beam line. The system is based on an event distribution system that broadcasts the timing information globally to all the equipment. Fast I/O hardware of the timing system is to distribute appropriate timing signals to accelerator systems, including the Injector, RFQ, DTL, and user's facilities. Signals to be distributed include the synchronized pulse triggers and event information of RF system and switching magnet power supplies for the 20MeV proton beam extraction.
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THPLS008 | Commissioning of the SOLEIL Booster | booster, injection, SOLEIL, emittance | 3281 | ||||
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SOLEIL is a 2.75 GeV new third generation synchrotron radiation facility under construction near Paris. The injector system is composed of a 100 MeV electron Linac pre-accelerator followed by a full energy (2.75 GeV) booster synchrotron. The booster lattice is based on a FODO structure with missing magnet. With a circumference of 157 m and low field magnets (0.74 T), the emittance is in the range of 110 to 150 nm.rad at 2.75 GeV. The magnets are excited at 3 Hz, using switched mode power supplies, with digital regulation. The LEP type RF cavity is powered by a 35 kW-352 MHz solid state amplifier. Closed orbits are measured turn by turn, using the BPM Libera digital electronics. The commissioning took place in October 2005, and an acceleration efficiency of 75% was obtained at the maximum energy. The main results achieved during that commissioning will be reported.
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THPLS029 | Commissioning of the Booster Synchrotron for the Diamond Light Source | booster, DIAMOND, injection, dipole | 3344 | ||||
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The Diamond booster is a 158 m circumference, 5 Hz synchrotron which accelerates the 100 MeV electron beam from a linac to 3 GeV for full-energy injection into the Diamond storage ring. The booster has been commissioned in the first few months of 2006, following successful initial 100 MeV trials at the very end of 2005. The injection and ramping process, orbit correction and essential beam physics measurements are discussed as are extraction and beam transport to the storage ring.
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THPLS099 | Fast Kicker Systems for the SOLEIL Booster Injection and Extraction, with Full Solid-state Pulsed Power Supplies | kicker, injection, power-supply, vacuum | 3505 | ||||
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The Booster of SOLEIL needs injection and extraction kicker systems with fast transition times, good flat top and low jitter, to allow a satisfactory injection efficiency of the Storage Ring injection. So all the kicker systems have been optimised, to fulfil specifications and to permit the use of solid state switching electronics. This contribution presents the ceramic vacuum chambers and magnets design, the specific pulse forming scheme and the realisation of the pulsed power supplies working up to 20 kV. Electrical and magnetic measurements results of kickers systems are given, and also its operation status from the first SOLEIL Booster injection in July 2005.
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THPLS113 | Design of a Fast Extraction Kicker for the Accelerator Test Facility | kicker, impedance, damping, SLAC | 3544 | ||||
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We present a study for the design of a fast extraction kicker to be installed in the Advanced Test Facility ring. The purpose of the project is to test the technologies to be used in the design of the extraction kickers for the ILC damping rings. The kicker's rise and fall times are important parameters in the design of the damping rings, as they limit the minimum distance between bunches and ultimately define a lower boundary for the ring length. We propose a stripline kicker composed of several 20-cm long sections, grouped in two locations in the ATF damping ring. An analytical study of the kicker's parameters and computer simulations using Microwave Studio* point out the strict requirements on the pulsers, in order to be able to satisfy the design parameters.
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*http://www.cst.com |
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