| Paper | Title | Page |
|---|---|---|
| WEPCH004 | Estimation of Transverse Coupling From Pinhole Images | 1921 |
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| The Brazilian Synchrotron Light Laboratory (LNLS) has recently started filling its storage ring straight sections with insertion devices. Last year a 2-Tesla Wiggler was successfully installed and integrated in the control system. An elliptically polarizing undulator is now under construction and scheduled to be installed in the next shutdown, by the end of the current year. The VUV beamline for the undulator is very demanding with respect to orbit stability and other beam parameters. Considerable reduction of the vertical emittance via reduction of the transverse coupling is a must in order for the undulator beamline to achieve its promised outstanding performance. In this paper we report on recent efforts to better understand the residual coupling in the machine and we describe preliminary proposals of viable solutions that aim at controlling the linear coupling within beamline specifications. | ||
| WEPCH005 | Advances in Beam Orbit Stability at the LNLS Electron Storage Ring | 1924 |
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| We describe recent efforts made at the Brazilian Synchrotron Light Source (LNLS) to improve beam orbit stability. The main driving force is the high positional stability required by some specific experiments and particularly by a high resolution undulator beamline which is being built at LNLS. Recent steps taken to improve orbit stability include the development of x-ray BPMs to measure the vertical position of the x-ray beam, analysis of RF BPM movement due to thermal load induced by synchrotron radiation after injection, new algorithms to deal with BPM electronics or control board false readings and revision and modification of their installations. In addition a weighted least squares method was developed to account for global correction while simultaneously privileging some local source point position. These upgrades are part of an ongoing work to improve beam orbit stability at LNLS. | ||
| WEPCH006 | Comparison between Simulations and Measurements of Low Charge Electron Bunch in the ELSA Facility | 1927 |
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| Dedicated focal spot size measurements carried out at the ELSA electron linear accelerator facility have provided detailed data which are suitable for benchmarking of different simulation codes for high charge bunch beam acceleration issued from an RF photo-injector source. We present some characteristic features of bunched electron beam propagation from beam formation at the photo-cathode to acceleration through RF cavities until the final focussing on a target, by using numerical simulations obtained with MAGIC, PARMELA, MAFIA, PARTRAN tool box codes. The challenges for the planned benchmarking are discussed. | ||
| WEPCH007 | Beam Dynamics Studies for the Spiral-2 Project | 1930 |
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| The SPIRAL-2 superconducting linac driver, which aims to deliver 5 mA, 20 A.MeV deuterons and 1 mA, 14.5 A.MeV q/A=1/3 heavy ions, is now entering the construction phase. It is composed of an injector composed of two ECR sources entering a 88 MHz RFQ, followed by a superconducting section based on independently phased quarter-wave cavities with warm focusing. This paper presents the status of the beam dynamics studies recently performed during this construction phase: consolidation and freezing of the linac design, update of the mass separation system or analysis of the proton capability. | ||
| WEPCH008 | The Beta-beam Decay Ring Design | 1933 |
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| The aim of the beta-beams is to produce highly energetic beams of pure electron neutrino and anti-neutrino, coming from beta radioactive decays of the 18Ne10+ and 6He2+, both at gamma = 100, directed towards experimental halls situated in the Frejus tunnel. The high intensity ion beams are stored in a ring until the ions decay. Consequently, all the injected particles will be lost anywhere in the ring, generating a high level of losses. The ring circumference has to be a multiple of the SPS circumference. The straight sections must be as long as possible in order to maximize the useful neutrino flux. The straight section length is chosen to be about 35% of the circumference length, which gives 1-km-long arcs. The bend field in the arcs is then reasonable. The arc has been chosen as a 2Pi phase advance insertion, which improves the optical properties (dynamic aperture and momentum acceptance) and allows the easy determination of the working point by the optics of the straight sections. | ||
| WEPCH009 | Loss Management in the Beta-beam Decay Ring | 1936 |
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| The aim of the beta-beams is to produce pure electronic neutrino and anti-neutrino highly energetic beams, coming from beta radioactive disintegration of the 18Ne10+ and 6He2+, both at gamma = 100, directed towards experimental halls situated in the Frijus tunnel. The high intensity ion beams are stored in a ring, until the ions decay. Consequently, all the injected particles will be lost anywhere around the ring generating a high level of losses. In order to keep a constant neutrino flux, the losses due to the decay of the radioactive ions are compensated with regular injections. The new ion beam is then merged with the stored beam with a specific RF program Two sources of losses have been considered: -The beta-decay products: their magnetic rigidity being different from the reference one, they are bent differently and lost. -The losses during the injection merging process. The first one needs a particular ring design in order to insert appropriate beam stoppers at the right place. The second one needs a specific collimation system which allows beam longitudinal halo cleaning between two successive injections. | ||
| WEPCH010 | Beam-based Alignment for the Storage Ring Multipoles of Synchrotron SOLEIL | 1939 |
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| First beam-based alignment (BBA) measurements will be carried out during the commissioning of the SOLEIL Storage Ring that will start in April 2006. The results will allow calibrating the zero reading of the 120 Beam Position Monitors (BPMs) with respect to the magnetic centre of the adjacent quadrupoles or sextupoles. BPMs being either adjacent to quadrupoles or sextupoles, we plan to resort to two different BBA methods related to each multipolar magnet. Moreover, as some BPMs are located near both quadrupole and sextupole, the use of both methods will allow us to cross-check the results. We will present here the first results and the comparison with the positions of the magnetic centres as obtained from the magnetic measurements. | ||
| WEPCH011 | Optimisation of a New Lattice for the ESRF Storage Ring | 1942 |
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| The installation of canted undulators in some of the straight sections of the ESRF storage ring is envisaged in the future. In order to free maximum space in the straight sections and minimise the reduction in length of the undulators, a new lattice, in which the straight section quadrupole triplets are replaced by doublets, is being studied. The paper describes the main features of the lattice and presents the experimental results achieved so far. | ||
| WEPCH012 | Comparison of Betatron Function Measurement Methods and Consideration of Hysteresis Effects | 1945 |
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| Two methods for determining the betatron functions in a storage ring were used to survey the linear optics at Delta. The fast orbit response analysis is used to gain betatron functions at the beam position monitors (BPMs) and dipole correctors. These are compared to betatron functions measured by the tune scan method which gives the beta functions in the quadrupoles. To improve the accuracy of the betatron functions obtained by the tune scan method a measuring procedure is introduced which considers the hysteresis effects in the quadrupole magnets. Systematic deviations in the beta functions measured between the two methods have been observed. The calibration errors of the BPMs can explain the observed deviations. With the orbit response analysis also the betatron phase advances between the measurement points can be calculated. Because these do not depend on the calibration errors, unlike the betatron functions, the differences between measurement and model can be determined more precise. A comparison of both methods with the optics model will be presented. | ||
| WEPCH013 | Electron Transport Line Optimization using Neural Networks and Genetic Algorithms | 1948 |
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| Methods of computational intelligence (CI) were investigated to support the optimization of the electron transfer efficiency from the booster synchrotron BoDo to the electron storage ring DELTA. Neural networks and genetic algorithms were analysed alternatively. At first both types of methods were trained on the basis of a theoretical model of the transport line. After the training various algorithms were used to improve the magnet settings of the real transport line elements with respect to the electron transfer efficiency. The results of different strategies are compared and prospects as well as limitations of CI-methods to the application of typical optimization problems in accelerator operation are discussed. | ||
| WEPCH015 | Measurement and Correction of Dispersion in the VUV-FEL | 1951 |
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| Increase in transverse beam size in the undulator caused by dispersive effects is one of the major limitations for the operation of FLASH, the VUV-FEL at DESY. Sources of the (spurious) dispersion are field errors and stray magnet fields in the undulator beam line as well as spurious dispersion created upstream of the undulator by, for instance, rf coupler kicks, magnet misalignments and field errors. The impact of these errors on dispersion generation depends on the actual operating conditions of the accelerator, so the dispersion must be measured and controlled frequently. In this paper we present numerical studies of spurious dispersion generation, first dispersion measurements and correction results. | ||
| WEPCH016 | Spurious Vertical Dispersion Correction for PETRA III | 1954 |
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| Spurious vertical dispersion, arising due to the misalignment and rotational errors of magnets in synchrotron radiation sources with low emittances, are highly undesirable as this contributes to the vertical beam size of the photon beam. This is a matter of concern in PETRA III, a 6GeV light source with a designed horizontal emittance of 1nm.rad and 1% emittance coupling. It has a hybrid lattice of FODO and DBA cells, which will be installed in one-eighth of the existing PETRA II ring. In this paper local and global vertical dispersion corrections are discussed. The global vertical dispersion is corrected using vertical corrector magnets (may also consider 12 skew quadrupole magnets), and the skew quadrupoles are used for local correction as well. Eight of them are placed close to the two damping wiggler sections used for minimizing the horizontal emittance. The remaining four are placed in the new octant with DBA cells where insertion devices are installed. | ||
| WEPCH017 | Front-to-end Simulation of the Injector Linac for the Heidelberg Ion Beam Therapy Centre | 1957 |
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| The injector linac of the Heidelberg ion beam therapy centre is currently in the commissioning phase. Its main components are two electron cyclotron resonance ion sources (ECRIS), a radio-frequency quadrupole accelerator (RFQ) and an interdigital H-type drift tube linac (IH-DTL). It will be able to accelerate beams of hydrogen-, helium-, carbon- and oxygen-ions up to a specific energy of 7 MeV per nucleon. This contribution focuses on the beam dynamics simulation of the transport lines and the accelerating structures. Three dedicated tools have been employed: Mirko for the beam transport, RFQmed for the particle dynamics through the RFQ and LORASR for the acceleration in the IH-DTL. Between the different beam dynamics codes interfaces have been implemented and a front-to-end simulation has been performed. Comparisons with alternative programmes confirm the results obtained. The work will enable us to investigate the behaviour of the machine in a theoretical model during the forthcoming operating. | ||
| WEPCH018 | Finite Elements Calculations of the Lattice and Ring Acceptance of the Heidelberg CSR | 1960 |
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| A new Cryogenic Storage Ring (CSR) is currently being designed at MPI-K in Heidelberg. This electrostatic ring, which will store ions in the 20~300 keV energy range (E/Q), has a total circumference of 35.2 m and a straight section length of 2.8 m. The ring design was at first carried out with the optics code MAD in the first order approximation. Further investigation of the optics was performed with the finite elements electrostatic code TOSCA. The individual elements of the CSR (deflectors and quadrupoles) were calculated then a model of the entire ring was simulated with successful storage (tracking) of 20keV protons for many turns. The lattice parameters thus obtained were compared with the MAD results and show good agreement. The dynamic ring acceptance was also calculated for the standard operating point. | ||
| WEPCH020 | Extending the Linear Least Squares Problem for Orbit Correction in Circular Accelerators | 1963 |
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| A method for extending the linear least squares problem applicable for correcting the orbit of circular accelerators is proposed. The method is based on the definition of a suitable cost function which weighs both orbit deviations and the correction effort, that is steerer kicks. The paper presents the full derivation of the formulas and the results of simulations. The application of this method for the Global Orbit Feedback system of the ELETTRA storage ring is being evaluated. | ||
| WEPCH021 | Generalized Twiss Coefficients Including Transverse Coupling and E-beam Growth | 1966 |
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| We use a generalization of the Twiss coefficients to the fully transverse coupled case. We show that the formalism is particularly useful to treat problems involving the beam optics of electrons propagating in undulators or solenoids. The method allows the treatment in analytical terms, we generalize the method including the effect of spatial charges and higher order multi-polar terms. The method is then applied to a specific example relevant to e-beam emittance dilution in solenoid and exotic undulators. | ||
| WEPCH022 | Study of the Effect of Multipolar Components in the SPARC Emittance Compensation Gun Solenoid | 1969 |
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| The SPARC photoinjector rf gun requires a solenoid immediately downstream for emittance compensation. The analysis of the measured solenoid magnetic maps shows the existence of multipolar components added to the pure solenoid field. The effect of these added fields on beam dynamics and possible correction schemes have been studied from the theoretical point of view and by numerical calculations based on PARMELA/TREDI codes. An accurate 3D numerical modelization by using CST EM Studio has been done, in order to investigate the source of these multipolar components and to suggest some design modifications aimed to reduce their magnitude. The results of this study are presented here. | ||
| WEPCH023 | Longitudinal Coherent Oscillation Induced in Quasi-isochronous Ring | 1972 |
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| Noise sources, which excite longitudinal coherent oscillation is discussed. Especially in a quasi-isochronous electron storage ring an identification of the noise sources is important to obtain an extremely short bunch. One possible source is a well-known rf noise in the acceleration field. The other is a magnetic field ripple, which changes a path-length for a revolution. The analytical formula for the longitudinal coherent oscillation is explained. It contains the path-length oscillation, which had never been considered. The third is a beam itself, probably be a coherent radiation loss. The driving term is not symmetric along the energy axis, then the oscillation amplitude depends on the higher order momentum compaction factor. | ||
| WEPCH024 | Matrix Formulation for Hamilton Perturbation Theory of Linearly Coupled Betatron Motion | 1975 |
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| Linear coupled motion in a circular accelerator was successfully parametrized through the transfer matrix approach, where normal mode Twiss and coupling parameters are defined as an extension of Courand and Snyder formulation. However it is not straightforward to assign analytical expressions to the coupling parameters. On the other hand the coupled motion was analytically solved by the Hamilton perturbation theory, which ingeniously describes the resonance phenomena. In the perturbation theory, however, the symplectic structure of the coupled motion is obscure in turn. Hence, for the purpose of combining both the theories with each other with keeping the respective virtues, we develop the matrix formulation based on the Hamilton perturbation theory. Since we have already known the solution of equation of motion, we can construct the transfer matrix in terms of the solution. Thus we formulate the betatron motion with linear coupling resonance in analytic and symplectic manner. As an application of the formulation, we investigate the two-dimensional beam ellipse in an electron storage ring. | ||
| WEPCH025 | COD Correction at the PF Ring by New Orbit Feedback Scheme | 1978 |
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| When we correct the global COD (closed orbit distortion), if we use the modified conversion matrix calculated by the eigen vector method with constraint conditions (EVC), the local orbit correction can be simultaneously done to fix the light source point in the insertion device. In the EVC, the local orbit correction is combined to the global orbit correction by the Lagrange's undetermined multiple method. In this paper, we show the machine study results at the PF Ring. | ||
| WEPCH026 | Recent Progress of Optics Measurement and Correction at KEKB | 1981 |
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| We present the progress of the optics measurement and the correction scheme of the KEKB operation for example off-momentum beta correction. | ||
| WEPCH028 | Position Shuffling of the J-PARC Main Ring Magnets | 1984 |
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| The J-PARC 50GeV main ring has 96 dipole, 216 quadrupole with 11 families and 72 sextupole magnets with 3 families. Magnets installation in the tunnel started last year and will be planed to finish by the end of next fiscal year. Field measurements of all magnets will soon finish by this March. Deviations for BL, B'L, B"L in dipole, quadrupole and sextupole magnets make COD, beta beat and third integer stopband, respectively. They can be reduced by choosing a pair of magnets with similar field deviation and by positioning them so as to cancel each other considering betatron phase (shuffling). In this paper, we will report our shufflling scheme chosen under the given schedule for installation and field measurements and also will show performances expected by the shufflings. | ||
| WEPCH029 | Injection and Extraction Orbit of the J-PARC Main Ring | 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. | ||
| WEPCH030 | Beam Dynamics of a 175MHz RFQ for an IFMIF Project | 1990 |
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| International Fusion Materials Irradiation Facility (IFMIF) is an accelerator-based neutron irradiation facility employing the D-Li stripping reaction, to produce the neutron field similar to the D-T Fusion reactor (2MW/m2, 20 dpa/year for Fe). The required beam current of 250 mA is realized by two beam lines of 125mA, and the output energies at injector, RFQ and DTL were designed to be 0.1, 5 and 40 MeV, respectively. The operation frequency of 175MHz was selected to accelerate the large current of 125mA. After an intensive beam simulation, the RFQ with a total length of 12.6 m was designed to keep the minimum emittance growth with the RF injection power of 2.3MW CW. For such a 12m-long RFQ, two coupling plates are indispensable in order to suppress higher modes in a longitudinal direction at least. From beam dynamics point views, the transmission co-efficient has been evaluated by TOUTATIS code, and it is found that the transmission decay within 0.5% can be achieved by employing a gap width of less than 4mm for a coupling plate design. | ||
| WEPCH032 | Orbit Correction System for S-LSR Dispersion-free Mode | 1993 |
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An ion storage ring S-LSR has been constructed at ICR, Kyoto Univ. It is a small ring with 22.557m circumference, and has an electron cooler and laser cooling section to achieve crystalline beam. In the commissioning process, closed orbit correction of a 7MeV proton beam has been successfully realized by means of Simplex Method. Responses to the correctors are linear only within narrow limits because of the space-charge effect in the electron cooler. Therefore, the correction must be repetition of small corrections. Under such condition, measured COD has been reduced less than 0.1mm. Orbit correction is necessary for 35keV Mg+ dispersion-free mode* using both bending magnets and electrostatic deflectors. Since electrostatic deflectors have relatively large field errors, it needs a special process to inject the beam into the dispersion-free mode ring. First circulation is under only the magnetic field, then, the electric field will be added little by little applying continuous COD correction. In this way the dispersion gradually diminishes with keeping stable orbit. In this paper we present the correction scheme and the trial to the dispersion-free circulation.
*M. Ikegami et al. Phys. Rev. ST-AB, 7, 120101-1 (2004). |
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| WEPCH033 | Single Particle Beam Dynamics Design of CSNS/RCS | 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. | ||
| WEPCH036 | Design of Short Bunch Compressors for the International Linear Collider | 1999 |
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| We present a two-stage bunch compressor system that was selected as alternative design in the ILC BCD (baseline configuration design). Initial beam with bunch length of 6 mm rms can be compressed to 150 micron rms in the bunch compressor, but the system uses a single chicane for each stage of compression, rather than the 12 chicanes used in the baseline design. We present the design scheme and performances of the system in detail, including scheme for emittance tuning in the system. | ||
| WEPCH038 | Nonlinear Characteristics of the TME Cell | 2002 |
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| The TME (Theoretical Minimum Emittance) cell is being used now for designing the lattice of different storage rings (SR sources, damping rings, FFAG accelerators, etc.). Strong sextupoles required to correct the natural chromaticity of the lattice reduce the dynamic aperture. In the paper we consider the main features of the nonlinear perturbation strength and its connection with the essential lattice parameters: horizontal emittance, betatron tunes, and natural chromaticity. The analytical results are compared with the computer simulation. | ||
| WEPCH040 | Further Development of Irradiation Field Forming Systems of Industrial Electron Accelerators | 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. | ||
| WEPCH041 | Analytic Study of Longitudinal Dynamics in Race-track Microtrons | 2008 |
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| Implementation of low energy injection schemes in the race-track microtron (RTM) design requires a better understanding of the longitudinal beam dynamics. Differently to the high energy case a low-energy beam will slip in phase relative to the accelerating structure phase. We generalize the concept of equilibrium or synchronous particle for the case of non-relativistic energies and introduce the notion of transition energy for RTMs. An analytical approach for the description of the synchronous phase slip is developed and explicit, though approximate, formulas which allow to define the equilibrium injection phase and fix the parameters of the accelerator are derived. The approximation can be improved in a systematic way by calculating higher order corrections. The precision of the analytical approach is checked by direct numerical computations using the RTMTrace code and was shown to be quite satisfactory. Explicit examples of injection schemes and fixing of RTM global parameters are presented. | ||
| WEPCH043 | On the Implementation of Experimental Solenoids in MAD-X and their Effect on Coupling in the LHC | 2011 |
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| The betatron coupling introduced by the experimental solenoids in the LHC is small at injection and negligible at collision energy. We present a study of these effects and look at possible corrections. Additionally we report about the implementation of solenoids in the MAD-X program. A thin solenoid version is also made available for tracking purposes. | ||
| WEPCH044 | Interaction Region with Slim Quadrupoles | 2014 |
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| An optical performance's improvement of the interaction region can be obtained with the addition of new quadrupoles in the forward detectors area. Such scenario would allow decreasing the $β*$ below the nominal value. The basic concept consists in using quadrupoles to break the quadratic behavior of $β$ in the free space between the IP and the IR triplets. In this new configuration we present the performance improvements and the hardware requirements. | ||
| WEPCH045 | Sorting Strategies for the Arc Quadrupoles of the LHC | 2017 |
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| The variation in the field gradient of the LHC arc quadrupoles can not be corrected independently by the dedicated trim quadrupole circuits. This may result to a beta function beating larger than the one accepted by the machine budget. In this respect, sorting strategies for the installation of these magnets were implemented in order to eliminate this effect, as locally as possible. Special care was taken for quadrupoles whose warm measurements showed large gradient errors due to an excessive magnetic permeability. The figures of merit used in the sorting and the results obtained for all 8 sectors of the LHC are detailed. The global optics function beating foreseen, as computed by both analytical estimates and simulations with MAD-X are finally presented. | ||
| WEPCH046 | Design and Validation with Measurements of the LEIR Injection Line | 2020 |
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| The CERN Low Energy Ion Ring (LEIR) commissioning started in the year 2005. O4+ and Pb54+ 4.2 MeV/nucleon ion beams are transferred from Linac 3 to LEIR through a low energy transfer line, for which the constraints and the resulting optics design are presented. First trajectory and dispersion measurements agreed only poorly with the theoretical model. Iterations of a refined optics model and further measurements improved the agreement between experimental observations and expectations. In particular, the effect of quadrupolar errors in the line dipole magnets is discussed. | ||
| WEPCH047 | Procedures and Accuracy Estimates for Beta-beat Correction in the LHC | 2023 |
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| The LHC aperture imposes a tight tolerance of 20% on the maximum acceptable beta-beat in the machine. An accurate knowledge of the transfer functions for the individually powered insertion quadrupoles and techniques to compensate beta-beat are key prerequisites for successful operation with high intensity beams. We perform realistic simulations to predict quadrupole errors in LHC and explore possible ways of correction to minimize beta-beat below the 20% level. | ||
| WEPCH048 | Measurement and Modeling of Magnetic Hysteresis in the LHC Superconducting Correctors | 2026 |
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| The Large Hadron Collider, now under construction at CERN, relies heavily on superconducting magnets for its optics layout: besides the main magnets, almost all the correcting magnets are superconducting. Along with clear advantages, this brings about complications due to the effects of persistent currents in the superconducting filaments. Correcting magnets that trim key beam parameters or compensate field errors of the main magnets (among others those due to hysteresis), are in their turn hysteretic. The measured magnetic hysteresis and its possible influence on accelerator operation will be presented, in particular the real-time compensation of decay and snapback in the main magnets, and the reproducibility between runs. A detailed characterization of minor hysteresis loops is given, as well as degaussing cycles and modeling work. | ||
| WEPCH049 | Closed Orbit Correction of TPS Storage Ring | 2029 |
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| A 3 GeV synchrotron storage ring is proposed in Taiwan to serve the synchrotron light users, especially for the x-ray community. The ring consists of 24 double-bend cells with 6-fold symmetry and the circumference is 518.4 m. The designed natural emittance with slightly positive dispersion in the straight sections is less than 2 nm-rad. This low emittance lattice structure needs strong quadrupoles and sextupoles and the closed orbit distortions are sensitive to the alignment errors in the quadrupoles and sextupoles as well. The closed orbit distortions due to tolerable magnetic errors are simulated and the correction scheme is proposed. Using singular value decomposition method, the closed orbit distortions are corrected and corrector strengths as well as the residual closed orbit distortions are obtained. | ||
| WEPCH050 | Correction of Vertical Dispersion and Betatron Coupling for the TPS Storage Ring | 2032 |
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| A proposed 3 GeV Taiwan Photon Source (TPS) is a low emittance (1.7 nm-rad) medium energy storage ring with 24 DBA cells. The vertical emittance due to betatron coupling and spurious vertical dispersion generated by the magnet errors and off-center orbits in sextupoles and quadrupoles are analyzed. The sensitivities due to magnetic alignment errors are estimated. Using the SVD method, the result of global vertical dispersion and betatron coupling correction is presented. | ||
| WEPCH051 | Isochronous Magneto-optical Structure of the Recirculator SALO | 2035 |
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| With the goal to provide low energy spread of electron beam, the magneto-optical structure of the recirculator SALO has been modified. All of its parts (an injection tract and arcs) were made isochronous and achromatic. Besides, with the purpose of the accelerating structure arrangement, the length of straight sections was enlarged. The amplitude and dispersion functions on various recirculator sections and design characteristics of the beam are submitted. | ||
| WEPCH052 | Injection System for Kharkov X-ray Source NESTOR | 2038 |
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| During the last three years a Kharkov X-ray generator NESTOR is under design and construction in NSC KIPT. According to the design report, electrons are injected in the storage ring at 100 MeV and ramped up to final energy 225 MeV. Due to compact design of the ring the injection trajectory of the beam will pass through fringe field of a NESTOR bending magnet. It brings additional difficulties on design of an injection channel. In the paper the layout, results of design and calculations of NESTOR injector channel are presented. The channel consists of two bending magnets, five-lens, asymmetrical, objective and two-lens matching cell to compensate dispersion and focusing effects of a dipole magnet fringe field and injection system elements (inflector). Presented results shows that designed lattice provides matching of injected beam parameters with the storage ring acceptance, is stable to element alignment errors and is easy controlled. The final values of the channel lens gradients can be defined only after measurements of inflector field profile. | ||
| WEPCH053 | Peculiarities of Influence of Coherency Processes at Charged Particles Channeling on Particle Beams Characteristics | 2041 |
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| In the work the length of reciprocal coherency existence and peculiarities of coherency of different states of channeled particles wave functions are discussed. It was shown that the length of coherent channeling depends on the monochromaticity of initial particle beam as well as on the interaction of channeled particles with thermal oscillations of the crystal lattice. Peculiarities of influence of coherency processes at relativistic and nonrelativistic charged particles channeling on spatial and angular characteristics of particle beam that has passed through a thin crystal are discussed. In was shown, that the influence of different particle states interference within the area of coherent channeling leads to very strong periodic dependence of final beam angular width from the crystal length. This effect allows to control beam parameters (e.g., to form narrower beam, that it was before falling on the crystal). Influence of coherency of particle states in a single channel and several channels on the angular distribution and the possibility of quasicharacteristic short-wave spontaneous and stimulated radiation is also studied. | ||
| WEPCH054 | Matrix Formalism for Current-independent Optics Design | 2044 |
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| Matrix formalism has been a powerful tool for beam optics designs. It not only facilitates computations but also plays an important role in formulating various design concepts. Here we extend the standard matrix formalism for the purpose of designing an optics that transports space-charge-dominated intense beam. Furthermore, we explore the concept of current-independent optics, which can be useful for systems such as high-brightness injectors and space-charge-dominated rings. Our discussion here is preliminary and limited to axisymmetric systems. | ||
| WEPCH055 | A New Algorithm for the Correction of the Linear Coupling at TEVATRON | 2047 |
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| The Fourier analysis of TBT data provides valuable information about the machine linear and non-linear optics. The recent upgrade of the Beam Position Monitors system made it possible to exploit this technique also at Tevatron. A program for the measurement and correction of the linear coupling based on this approach has been integrated in the TEVATRON control system. With respect to the method based on the empirical adjustment of the strength of the skew quadrupoles, the new method has the advantage of being faster and of allowing the measurement of the coupling also during the acceleration. Moreover it offers also information about the sum coupling coefficient and about the location of the sources of coupling. | ||
| WEPCH057 | Measurement and Optimization of the Lattice Functions in the Debuncher Ring at Fermilab | 2050 |
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| A goal of the Tevatron Run-II upgrade requires substantial increase of antiproton production. The central step towards this goal is increasing the Debuncher ring admittance. Detailed understanding of the Debuncher's optics, aperture limitations and lattice functions is necessary. The method of the response matrix optimization has been used to determine quadrupole errors and corrections to the design functions. The measurement accuracy is about 5% due to the Beam Position Monitor system resolution and the small number of steering elements in the machine. We have used these accurate measurements to redesign the machine optics to maximize the acceptance of the Debuncher where the main limiting apertures are the stochastic cooling pickups and kickers. Accuracy of the measurements and the limitations are discussed as well as details of the optics modification. | ||
| WEPCH058 | Progress with Collision Optics of the Fermilab Tevatron Collider | 2053 |
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| Recent advances in the measurement and modeling of the machine parameters and lattice functions at the Tevatron allowed modifications of the collision optics to be performed in order to increase the collider luminosity. As the result, beta functions in the two collision points were decreased from 35cm to 29cm which resulted in ~10% increase of the peak luminosity. In this report we describe the results of optics measurements and corrections. We also discuss planned improvements, including the new betatron tune working point and correction of the beta function chromaticity. | ||
| WEPCH059 | Linear Lattice Modeling of the Recycler Ring at Fermilab | 2056 |
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| The Recycler Ring at Fermilab is a fixed 8 GeV kinetic energy storage ring, by the use of permanent magnets in the ring lattice. It is a strong focusing FODO lattice made up of either two gradient magnets or two quadrupoles(in dispersion free straight sections). The magnetic properties of all magnets used were measured before installation and surveyed in place to minimize possible errors. Nevertheless, substantial differences are found in tunes and beta functions between the existing linear model and the real storage ring. It results in difficulties when tuning the machine to new lattice conditions. We are trying to correct the errors by matching the model into the real machine using Orbit Response Matrix(ORM) method. The challenge with ORM particular in this ring and the results are presented in this paper. | ||
| WEPCH060 | Linear and Nonlinear Coupling Using Decoupling Transformations | 2059 |
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| Linear coupling in a storage ring is conveniently analyzed in terms of transformations that put the single-turn map into block-diagonal form. Such a transformation allows us to define new variables, in which the dynamics are uncoupled. Thus, for example, the symplectic conditions are simply that the phase area in each of the uncoupled variables is preserved. In principle, a similar approach may be taken to nonlinear coupling; we discuss such an approach in this paper, giving some simple illustrations of the ideas, based on the well-known techniques of normal form analysis. We also discuss some obstacles to finding a nonlinear decoupling transformation in the general case. | ||
| WEPCH061 | SABER Optical Design | 2062 |
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| SABER, the South Arc Beam Experimental Region, is a proposed new beam line facility designed to replace the Final Focus Test Beam at SLAC. In this paper, we outline the optical design features and beam parameters now envisioned for SABER. A magnetic chicane to compress positron bunches for SABER and a bypass line that could transport electrons or positrons from the two-thirds point of the linac to SABER, bypassing the LCLS systems, are also discussed. | ||
| WEPCH062 | Precision Measurement and Improvement of Optics for e+, e- Storage Rings | 2065 |
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| Through horizontal and vertical excitations, we have been able to make a precision measurement of linear geometric optics parameters with a Model-Independent Analysis (MIA). We have also been able to build up a computer model that matches the real accelerator in linear geometric optics with an SVD-enhanced Least-square fitting process. Recently, with the addition of longitudinal excitation, we are able to build up a computer virtual machine that matches the real accelerators in linear optics including dispersion without additional fitting variables. With this optics-matched virtual machine, we are able to find solutions that make changes of many normal and skew quadrupoles for machine optics improvement. It has made major contributions to improve PEP-II optics and luminosity. Examples from application to PEP-II machines will be presented. | ||
| WEPCH063 | Measurements and Modeling of Eddy Current Effects in BNL's AGS Booster | 2068 |
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| Recent beam experiments at BNL's AGS Booster have enabled us to study in more detail the effects of eddy currents on the lattice structure and our control over the basic lattice parameters of betatron tune and chromaticity. The Booster is capable of operating at ramp rates as high as 8 T/sec. At these ramp rates eddy currents in the vacuum chambers have significant effects on the fields and gradients seen by the beam as it is accelerated. The Booster was designed with these effects in mind and to help control the field uniformity and linearity in the Booster Dipoles special vacuum chambers were designed with current windings to negate the effect of the induced eddy currents. In this report results from measurements of these effects will be presented. Results from modeling and comparisons to the measurements will also be presented. | ||
| WEPCH064 | Fast Compensation of Global Linear Coupling in RHIC using AC Dipoles | 2071 |
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| Global linear coupling has been extensively studied in accelerators and several methods have been developed to compensate the coupling vector C using skew quadrupole families scans. However, scanning techniques can become very time consuming especially during the commissioning of an energy ramp. In this paper we illustrate a new technique to measure and compensate, in a single machine cycle, global linear coupling from turn-by-turn BPM data without the need of a skew quadrupole scan. The algorithm is applied to RHIC BPM data using AC dipoles and compared with traditional methods. | ||
| WEPCH065 | Lattices for High-power Proton Beam Acceleration and Secondary Beam Collection, Cooling, and Deceleration | 2074 |
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| Rapid-cycling synchrotrons are used to accelerate high-intensity proton beams to energies of tens of GeV for secondary beam production. After primary beam collision with a target, the secondary beam can be collected, cooled, accelerated or decelerated by ancillary synchrotrons for various applications. In this paper, we first present a lattice for the main synchrotron. This lattice has: a) flexible momentum compaction to avoid transition and to facilitate RF gymnastics b) long straight sections for low-loss injection, extraction, and high-efficiency collimation c) dispersion-free straights to avoid longitudinal-transverse coupling, and d) momentum cleaning at locations of large dispersion with missing dipoles. Then, we present a lattice for a cooler ring for the secondary beam. The momentum compaction across half of this ring is near zero, while for the other half it is normal. Thus, bad mixing is minimized while good mixing is maintained for stochastic beam cooling. | ||
| WEPCH067 | Implementation of TPSA in the Mathematica Code LieMath | 2077 |
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| The Lie Algebra package LieMath written in the Mathematica language constructs the beamline map in a single-exponent Lie generator form. The algorithm (BCH-based map concatenation) has been recently enhanced with Truncated Power Series Algebra (TPSA) techniques.The polynomials produced by the series expansion of the Hamiltonian are replaced with arrays of coefficients (derivative structures) and the Poisson bracket and BCH are defined as operations on such structures. We have confirmed the statement that using automatic differentiation instead of symbolic operations increases the speed by least an order of magnitude. The code is equipped with a MAD parser and a normal form block allowing it to extract nonlinear chromaticity and amplitude detuning. The notebook was applied in FFAG studies and may be useful for the linear collider final focus or collimation systems. | ||
| WEPCH068 | 6-D Beam Dynamics Studies in EMMA FFAG | 2080 |
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Extensive simulations of 6-D transmission simulations in linear, non-scaling FFAGs, based on gutter rapid acceleration, are reported. They concern two different on-going projects: the 20~GeV muon accelerators in the Neutrino Factory (NuFact) with ISS parameters* and a 20~MeV electron model of these machines, EMMA**.
*http://www.hep.ph.ic.ac.uk/iss/**http://hepunx.rl.ac.uk/uknf/wp1/emodel/ |
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| WEPCH072 | The High Order Non-linear Beam Dynamics in High Energy Storage Ring of FAIR | 2083 |
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| The High Energy Storage Ring (HESR) is part of the international project FAIR for antiproton physics with beam in the momentum range from 1.5 to 15 GeV/c to explore the research areas of hadron structure and quark-gluon dynamics. An important feature of the project is the combination of phase space cooled beams with thick internal targets. Therefore there are two obvious reasons of beam heating: the target-beam interaction and the intra-beam scattering. Another source of the beam size growth is the higher order resonances. In the paper we investigate the non-linear beam dynamics together with different correction schemes minimizing this effect and compare with other sources of beam heating. Since the tune working point has a spread dependent on the chromaticity correction scheme and space charge, we include in our consideration both effects as well. All beam dynamics calculations are carried out with the SIMBAD code from the Unified Accelerator Library (UAL). We use 10000 macro particles, grid sizes 64x64 and 1000 turns per run. | ||
| WEPCH073 | Asymptotic Analysis of Ultra-relativistic Charge | 2086 |
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| A new approach is developed for analysing the dynamic behaviour of distributions of charged particles in an electromagnetic field. Noting the limitations inherent in the Lorentz-Dirac equation for a single point particle, a simple model is proposed for a charged continuum interacting self-consistently with the Maxwell field in vacuo. The model is developed using intrinsic tensor field theory and exploits to the full the symmetry and light-cone structure of Minkowski spacetime. This permits the construction of a regular stress-energy tensor whose vanishing divergence determines a system of non-linear partial differential equations for the velocity and self-fields of accelerated charge. Within this covariant framework a particular perturbation scheme is motivated by an exact class of solutions to this system describing the evolution of a charged fluid under the combined effects of both self and external electromagnetic fields. The scheme yields an asymptotic approximation in terms of inhomogeneous linear equations for the self-consistent Maxwell field, charge current and time-like velocity field of the charged fluid and is defined as an ultra-relativistic configuration. | ||
| WEPCH074 | Progress with Non-linear Beam Dynamic Studies of the Diamond Storage Ring | 2089 |
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| The conflicting requirements of high-brightness photon beams combined with adequate beam lifetime and high injection efficiency mean careful control of the non-linear lattice is crucial to achieving optimum performance. As part of the optimisation of the Diamond storage ring, studies have been made of both the Touschek lifetime and storage ring injection process, with the help of on-momentum and off-momentum frequency maps. The effect of chromaticity on Touschek lifetime has also been investigated and several new sextupole settings were identified achieving good Touschek lifetime and injection efficiency. | ||
| WEPCH075 | Effect of Insertion Devices on Beam Dynamics of the Diamond Storage Ring Using Kick Maps | 2092 |
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| The effect of the all Phase-I Insertion Devices (IDs) on the beam dynamic of the Diamond storage ring has been investigated using the kick map modelisation of the IDs. Kick maps have been produced with high accuracy using the computer code RADIA, considering many longitudinal harmonics. The effect of IDs on the dynamic aperture, Touschek lifetime and injection efficiency in the low emittance lattice, was investigated considering both coupling errors and physical engineering apertures. Harmful resonances have been identified using Frequency Map Analysis (FMA) and full 6D tracking was performed to estimate the Touschek lifetime and the injection efficiency. Additionally, the kick maps have been used to generate feed-forward tables for compensation of linear optics distortion. | ||
| WEPCH076 | Renormalization Group Reduction of the Frobenius-Perron Operator | 2095 |
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| The Renormalization Group (RG) method is adopted as a tool for a constructive analysis of the properties of the Frobenius-Perron Operator. The renormalization group reduction of a generic symplectic map in the case, where the unperturbed rotation frequency of the map is far from structural resonances driven by the kick perturbation has been performed in detail. It is further shown that if the unperturbed rotation frequency is close to a resonance, the reduced RG map of the Frobenius-Perron operator (or phase-space density propagator) is equivalent to a discrete Fokker-Planck equation for the renormalized distribution function. The RG method has been also applied to study the stochastic properties of the standard Chirikov-Taylor map. | ||
| WEPCH077 | Particle Tracking in a Sextupole Field using the Euler Method Approximation | 2098 |
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| The purpose of this paper is to evaluate any differences in the single particle tracking through a magnetic lattice when sextupoles are treated either like sliced or single-kick elements. Only on-energy transverse motion is considered. Convergence and symplecticity of the method of sliced sextupoles are discussed. Dynamic apertures and transverse phase spaces applied to the Elettra synchrotron lattice are compared for the two cases. | ||
| WEPCH078 | Measurement of Wake Effects by Means of Tune Shift in the KEKB Low-Energy Ring | 2101 |
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| The electron cloud produced by the positron beam induces single-bunch and coupled-bunch wakes, in addition to a tune shift. Effects of the dipole wake-field including the electron cloud were tried to measure in the KEKB Low Energy Ring. A test bunch was placed behind a bunch-train of the positron beam, even though a test bunch itself might interact with the remaining electron cloud. We measured a current-dependent tune-shift of a test bunch under constant train-current, while changing the bucket position of a test bunch. The tune shift indicated a strong defocusing field, however, tended to a focusing field when a test bunch approached a train with high train-current. The results are discussed, considering variations of the electron cloud density. | ||
| WEPCH079 | Effects of Intrinsic Nonlinear Fields in the J-PARC RCS | 2104 |
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| In order to accelerate a high intense proton beam with small particle losses, the J-PARC RCS, which is being constructed at JAEA, has a large acceptance. In such synchrotrons, the nonlinear motion of the beam particles, especially moving away from the axis of the elements, is a common issue, and it becomes essential to consider intrinsic field nonlinearities. The main sources of nonlinear magnetic fields in the RCS are as follows: fringes of the main dipole and quadrupole magnets, sextupole fields used for the chromatic correction, leak fields from the injection and extraction beam lines, etc. In this paper, we will discuss influences of the intrinsic field nonlinearities and a cure for the induced betatron resonances, based on single-particle and multi-particle tracking simulations. | ||
| WEPCH080 | Beam Simulation of SQQ Injection System in KIRAMS-30 Cyclotron | 2107 |
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| The injection system of KIRAMS-30 cyclotron consists of a double gap buncher, an SQQ, and a spiral inflector. Initial beam with 100 mmmrad has been generated by random Gaussian function in the transverse plane and random uniform function in the longitudinal direction. Using the 3D electric and magnetic fields of a buncher, SQQ, inflector, and return-yoke bore, the characteristics of the beam injected into the KIRAMS-30 cyclotron's central region has been obtained. This paper presents the results of its beam characteristics and parameters of each beam element. | ||
| WEPCH081 | Injection of The Proton Beam Into The Compact Cyclotron with Solenoid | 2110 |
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| The proton (H-) low (100 mkA) intensity beam injected by means of the solenoid comes to the first cyclotron orbit without the beam emittance deterioration. This is demonstrated by computer simulation. | ||
| WEPCH082 | Simulation of Ions Acceleration and Extraction in Cyclotron C400 | 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. | ||
| WEPCH085 | Algorithms for Chromatic Sextupole Optimization and Dynamic Aperture Increase | 2116 |
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| Strong chromatic sextupoles compensating natural chromaticity of a storage ring may reduce dynamic aperture drastically. In the case of several sextupole families, one can find a lot of ways to correct chromaticity, which provides different sizes of the dynamic aperture. Finding a solution that gives the largest dynamic aperture is an important task for the storage ring design and operation. The paper discusses several approaches to sextupole arrangement optimization in order to obtain a large dynamic aperture. | ||
| WEPCH086 | Adiabatic Theory of Slow Extraction of Particles from a Synchrotron | 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. | ||
| WEPCH087 | Normal Form for Beam Physics in Matrix Representation | 2122 |
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| The modeling of long beam evolution dynamics in nonlinear accelerator structures has raised new interest in the effective methods of nonlinear effects calculation. Moreover, it is preferably to use both analytical tools and numerical methods for evolution modeling. Usually the standard numerical methods and computer codes are based on the concept of symplectic transfer maps, whereas the analytical tool is the theory of normal forms. The method of normal forms can be realized in symbolic and numerical modes easily enough. In this paper, we discuss the normal form theory based on the matrix formalism for Lie algebraic tools. This approach allows using well known methods of matrix algebra. This permits to compute necessary matrices step-by-step up to desired order of approximation. This procedure leads to more simple structure of matrix representation for very complicated structure of this map does not allow using this map for practical computing. Therefore, it is necessary to transform this map in more appropriate form. In another words the new matrix representation for the map is particularly simple and has explicit invariants and symmetries. | ||
| WEPCH088 | High Order Aberration Correction | 2125 |
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| It is known that modern accelerators fall under nonlinear aberrations influence. The most of these aberrations have harmful character, and their effect must be maximally decreased. There are a set of approaches and codes to solving this problem. In this paper, we consider an approach for solving this problem using the matrix formalism for Lie algebraic tools. This formalism allows reducing the starting problem to linear algebraic equations for aberration coefficients, which are elements of corresponding matrices. There are discussed results evaluated using suggested approach and nonlinear programming tools. Some examples of corresponding results are given. | ||
| WEPCH092 | Dynamical Aperture Studies for the CERN LHC: Comparison between Statistical Assignment of Magnetic Field Errors and Actual Measured Field Errors | 2128 |
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| It is customary to evaluate the performance of a circular particle accelerator by computing the dynamical aperture, i.e., the domain in phase space where bounded single-particle motion occurs. In the case of the LHC the dynamical aperture computation is performed by assuming a statistical distribution of the magnetic field errors of various magnets' classes: the numerical computations are repeated for a given set of realisations of the LHC ring. With the progress in the magnet production and allocation of the available positions in the ring, the statistical approach has to be replaced by the computation of one single configuration, namely the actual realisation of the machine. Comparisons between the two approaches are presented and discussed in details. | ||
| WEPCH093 | Parameter Scans and Accuracy Estimates of the Dynamic Aperture of the CERN LHC | 2131 |
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| Techniques to make use of large distributed computing facilities allow for denser parameter scans of the dynamical aperture, i.e., the domain in phase space where bounded single-particle motion prevails. Moreover, one can also increase the number of 'seeds' each of which represents a possible realisation of multipolar components around the machine. In this paper the dependence of the dynamical aperture on the step size of the grid of initial conditions and on the number of seeds is studied. Estimates on the accuracy of the dynamic aperture are derived and the definition of an improved protocol for numerical simulations is presented. | ||
| WEPCH094 | An Early Beam Separation Scheme for the LHC | 2134 |
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| The high nominal luminosity of the LHC requires a large number of bunches spaced by about 7.5 m. To prevent more than one head-on collision in each interaction region, a crossing angle of 0.285 mrad is necessary. A side effect of this crossing angle is the increase of the effective transverse beam cross-section, thereby decreasing the luminosity by some 16%. For the LHC upgrade, depending on the focusing scenarios, this loss significantly increases and largely offsets the potential gain of a stronger focusing. In this paper we analyze a strategy to circumvent this difficulty, based an early beam separation using small dipoles placed at a few meters from the interaction point, deep inside the detectors. This allows quasi co-linear head-on collisions at the crossing point only. From the beam dynamics point of view, the essential constraint is to control the long-range beam-beam interactions in a scenario where the normalized beam separation is not constant. In this paper the criteria of the analysis and the performance improvement obtained with the scheme are discussed. The strength of the dipoles is estimated as well as the impact on the detectors structure. | ||
| WEPCH095 | Models to Study Multi-bunch Coupling through Head-on and Long-range Beam-beam Interactions | 2137 |
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| In the LHC almost 6000 bunches will collide in four interaction points where they experience head-on as well as clustered long range interactions. These lead to a coupling between all bunches and coherent beam-beam effects. For two colliding bunches this is well understood. However, for a large number of bunches colliding with different collision patterns, it results in a complex spectrum of oscillation frequencies with consequences for beam measurements and Landau damping. To study the coherent beam-beam modes, three complementary models have been developped and will be described in this report. Two of these methods rely on self-consistent multi-bunch and multi-particle tracking while the third is a semi-analytic model based on a complex matrix algorithm. The three methods together provide useful information about the beam-beam coupling of multi bunch beams and together provide a deeper insight into the underlying physics. | ||
| WEPCH096 | Measurement and Correction of the 3rd Order Resonance in the Tevatron | 2140 |
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| At Fermilab Tevatron BPM system has been recently upgraded resulting much better accuracy of beam position measurements and improvements of data acquisition for turn-by-turn measurements. That allows one to record the beam position at each turn for 8000 turns for all BPMs (118 in each plane) with accuracy of about 10-20 μm. In the last decade a harmonic analysis tool has been developed at CERN that allows relating each FFT line derived from the BPM data with a particular non-linear resonance in the machine. In fact, one can even detect the longitudinal position of the sources of these resonances. Experiments have been performed at the Tevatron in which beams have been kicked to various amplitudes to analyze the 3rd order resonance. It was possible to address this rather large resonance to some purposely powered sextupoles. An alternative sextupole scheme allowed the suppression of this resonance by a good factor of 2. Lastly, the experimental data are compared with model calculations. | ||
| WEPCH097 | Beam Dynamics in Compton-ring Gamma Sources | 2143 |
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| Electron storage rings with a laser cavity are promising intensive sources of polarized hard photons to generate polarized positron beams. The dynamics of electron bunches circulating in a storage ring and interacting with high-power laser pulses is studied both analytically and by simulation. Common features and difference in the bunch behavior interacting with an extremely high power laser pulse (polarized positron source for the ILC project) and a moderate pulse (source for CLIC) are shown. Also considerations on particular lattice designs for both rings are presented. | ||
| WEPCH100 | Application of the Lie-transform Perturbation Theory for the Turn-by-turn Data Analysis | 2146 |
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| Harmonic analysis of turn-by-turn BPM data is a rich source of information on linear and nonlinear optics in circular machines. In the present report the normal form approach first introduced by R. Bartolini and F. Schmidt is extended on the basis of the Lie-transform perturbation theory to provide direct relation between the sources of perturbation and observable spectra of betatron oscillations. The goal is to localize strong perturbing elements, find the resonance driving terms - both absolute value and phase - that are necessary for calculation of the required adjustments in correction magnet circuits: e.g. skew-quadrupoles for linear coupling correction. The theory is nonlinear and permits to analyze higher order effects, such as coupling contribution to beta-beating and nonlinear sum resonances. | ||
| WEPCH101 | Ion Motion in the Adiabatic Focuser | 2149 |
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The Adiabatic Focuser* works by having a focusing channel whose strength increases with distance down the channel. In this situation electrons of various energies and various transverse oscillation phase all are transversely focused. The concept works with external focusing, but would be very effective in a plasma ion focusing channel where the density of ions is simply increased as one goes down the channel. In the original work (Ref 1) motion of the ions was not included (as it was assumed to be a small effect). Recently, it has been suggested that ion motion in an adiabatic focuser would be significant and, even, preclude operation of the focuser as previously envisioned**. In this paper we numerically study the ion motion in the focuser. The ions clearly influence each other and, most importantly, are influenced by the electric field of the electrons being focused. It is shown that parameters can be selected such that the adiabatic focuser works as well as originally envisioned.
*P. Chen et al. Phys. Rev. Lett. 64, 1231 (1990).**J. R. Rosenzweig, et al. Phys. Rev. Lett. 95, 195002 (2005). |
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| WEPCH102 | Studies of the Nonlinear Dynamics Effects of APPLE-II Type EPUs at the ALS | 2152 |
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| Elliptically Polarizing Undulators (EPUs) have become more and more popular at synchrotron radiation sources, providing full polarization control of the photon beam. The fields of the most commonly used APPLE-II type EPUs have a very fast, intrinsic field roll-off, creating significant non-linearities of the beam motion with in some cases large impact on the dynamic (momentum) aperture. In general, the nonlinear effects get stronger with longer periods and higher undulator magnetic fields. One of the planned future beamlines at the ALS (MERLIN) will use a quasiperiodic EPU with 9 cm period and maximum B fields of about 1.3 T. We will present simulation studies for the proposed shimming schemes for this future device to reduce the nonlinear effects to acceptable values, as well as experimental studies for the existing 5 cm period EPUs already installed in the ALS. | ||
| WEPCH103 | Ion Effects in the Electron Damping Ring of the International Linear Collider | 2155 |
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| Ion-induced beam instabilities and tune shifts are critical issues for the electron damping ring of the International Linear Collider (ILC). To avoid conventional ion trapping (multi-turn trapping), a long gap is introduced in the electron beam by omitting a number of successive bunches out of a long train. However, the beam can still suffer from the fast ion instability (FII), driven by ions that last only for a single passage of the electron bunches. Our study shows that the ion effects can be significantly mitigated by using multiple gaps, so that the stored beam consists of a number of relatively short bunch trains. The ion effects in the ILC damping rings are investigated using both analytical and numerical methods. | ||
| WEPCH104 | Observation of the Long-range Beam-beam Effect in RHIC and Plans for Compensation | 2158 |
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| At large distances the electromagnetic field of a wire is the same as the field produced by a bunch. Such a long-range beam-beam wire compensator was proposed for the LHC, and single beam tests with wire compensators were successfully done in the SPS. RHIC offers the possibility to test the compensation scheme with colliding beams. We report on measurements of beam loss measurements as a function of transverse separation in RHIC at injection, and comparisons with simulations. We present a design for a long-range wire compensator in RHIC. | ||
| WEPCH106 | Stationary Beam Electron Transport in AIRIX for the TRAJENV Code | 2161 |
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| In the framework of the AIRIX program, the electron beam propagation between the injector and the X-conversion target is routinely simulated with the 2D TRAJENV code. We describe the physical models implemented in the code for a intense stationary beam. We present both the modeling of applied electromagnetic forces in induction cells and self generated ones. To avoid the cell damage due to target debris generated by the electron beam impact, a thin debris shield has been tested upstream the X-ray converter. Such a thin foil located in the beam pass, is taken into account in TRAJENV. We describe the modeling and the influence of the foil on the beam. | ||
| WEPCH107 | Contributors to AIRIX Focal Spot Size | 2164 |
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| High intensity electron beam focusing is a key issue for the successful development of flash radiography at hydro test facilities. AIRIX is a 2 kA, 19 MeV, 60 ns, single shot linear accelerator that produces X-rays from the interaction between relativistic electrons and a Tantalum solid target (Ta). A simulation tool has been developed to model the pulsed-beam dynamics through the accelerator from the cathode to the target. This simulator has allowed to estimate the contribution to the beam size on the target (focal spot) of beam emittance, pulse energy dispersion, pulse rising and falling fronts and the ion production on the target. The quantified contributions of these phenomena are reviewed here. | ||
| WEPCH109 | Comprehensive Benchmark of Electromagnetic 3D Codes in Time and Frequency Domain | 2167 |
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| A comprehensive benchmark of todays most powerful numerical 3D Eigenmode and Time Domain Solvers has been performed using the input geometry of a HOM-damped cavity and a highly lossy waveguide load developed at BESSY. The paper details the simulations results together with existing experimental data. | ||
| WEPCH110 | Calculation of Wake Potentials in General 3D Structures | 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. | ||
| WEPCH111 | Time Domain Radiation of a Gaussian Charge Sheet Passing a Slit in a Conducting Screen | 2173 |
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| A semi-analytical method is proposed to calculate in time-domain the radiation of a relativistic Gaussian charge sheet travelling parallel to a slotted conducting screen. The method is based on transient line current elements as basis functions which have a triangular time dependence. Making use of duality magnetic current elements are used in the slot region. Radiation fields are shown and the transverse kick received by a test charge is given. The dual problem, the scattering of the fields at a conducting strip, is also treated. The main purpose of the paper is to present an effective algorithm which is easy to implement for computing and visualising plane scattering and diffraction problems in time domain. | ||
| WEPCH112 | Database Extension for the Beam Dynamics Simulation Tool V-code | 2176 |
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| The beam dynamics simulation tool V-Code has been proved to be very useful in redesigning the injector layout at the superconducting linear accelerator in Darmstadt (S-DALINAC). Modifications in the beam optics are necessary because a new source of polarized electrons should be installed in addition to the existing thermionic gun. The calculations are performed with V-Code which is designed to handle a large amount of individual beam line elements and can therefore be used for extensive accelerator studies. The available database includes all the necessary components like solenoids, quadrupoles and rf cavities, but as a result of their consecutive treatment overlapping external fields are not allowed. Due to geometrical restrictions in the assembly of the new source a space-saving candidate of a quadrupole triplet violates this software-related condition if it is regarded as three distinct quadrupoles. Consequently, a more general beam line element has to be created which treats the lenses as a single unit without interference of their fields to attached cells. The indispensable data base extension together with simulation results and implementation verifications will be presented. | ||
| WEPCH113 | Numerical Impedance Calculations for the GSI SIS-100/300 Kickers | 2179 |
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| Fast kicker modules represent a potential source for beam instabilities in the planned Facility for Antiproton and Ion Research (FAIR) at the Gesellschaft für Schwerionenforschung (GSI), Darmstadt. In particular, the more than fifty kicker modules to be installed in the SIS-100 and SIS-300 synchrotrons are expected to have a considerable parasitic influence on the high-current beam dynamics. Here we present our numerical investigations of the longitudinal and transverse kicker coupling impedances using a specialized electromagnetic field software. Besides the coupling to the external network, particular attention is paid to the question whether a resistively-coated ceramic beam pipe is able to reduce coupling impedances and ferrite heating significantly. | ||
| WEPCH114 | On the Development of a Self-consistent Particle-in-cell (PIC) Code Using a Time-adaptive Mesh Technique | 2182 |
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| For a large class of problems the self-consistent simulation of charged particle beams in linear accelerators is necessary. Especially, in all low-energetic sections such as injectors the self-consistent interaction of particles and fields has to be taken into account. Well-known programs like the MAFIA TS Modules typically use the Particle-in-cell (PIC) method for beam dynamics simulations. Since they use a fixed computational grid which has to resolve the bunch adequately, they suffer from enormous memory consumption. Therefore and especially in the 3D case, only rather short sections can be simulated. A remedy to this limitation is the usage of a grid which refines itself in the vicinity of particles. For this purpose, a new code called SMOVE based on a time-adaptive grid is being developed. First promising results will be presented at the conference. | ||
| WEPCH115 | Numerical Simulation and Optimization of a 3-GHz Chopper/Prebuncher System for the S-DALINAC | 2185 |
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| A new source of polarized electrons with an energy of 100 keV is presently being developed at the superconducting Darmstadt electron linear accelerator S-DALINAC for future nuclear- and radiation-physics experiments. The pulsed electron beam emitted by the photocathode will be cut to 50 ps by a chopper operated at 3 GHz, and further bunch compression down to 5 ps will be achieved by a two-stage prebuncher section. The chopper-prebuncher system is based on similar devices used at the Mainz Mikrotron (MAMI) where the accelerator frequency is slightly smaller (2.4 GHz). For the chopper, a cylindrical resonator operating at TM110 mode is selected to deflect the electron beam onto an ellipse, i.e., both horizontally and vertically. This is simply achieved by particular slits on both ends of the resonator. The prebunching system consists of two cavities. For increasing the longitudinal capture efficiency, the first cavity will be operated at the fundamental accelerator frequency of the S-DALINAC of 3 GHz, and the second cavity at 6 GHz. The cavities are designed to work at the TM010 mode and TM020 mode for the fundamental and first harmonic, respectively. | ||
| WEPCH116 | Recent Simulation Results of the Polarized Electron Injector (SPIN) of the S-DALINAC | 2188 |
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| Recent design and development for a polarized electron source (SPIN) for the recirculating superconducting electron linear accelerator S-DALINAC will be presented. The polarized electron beam will be produced by photoemission from an InAlGaAs/GaAs superlattice cathode and will be accelerated to 100 kV electrostatically. The results of the beam dynamics simulation will be shown in detail. The start phase space of the electron bunch behind the gun has been approximated. The transverse focusing system consists of very short quadrupoles. Further main components of the new injector are a Wien filter, a Mott polarimeter, a chopper-prebuncher system (based on devices used at the Mainz Mikrotron MAMI), and diverse beam diagnostic tools. For the approximation of the start phase space CST MAFIA is used, and for the beam dynamic simulation VCode is used. | ||
| WEPCH117 | Beam Dynamics of an Integrated RFQ-drifttube-combination | 2191 |
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| In the frame of a collaboration with the GSI in Darmstadt an RFQ-Drifttube-Combination for the Heidelberg cancer therapy center HICAT has been designed, built and successfully beam tested at the IAP Frankfurt. The integration and combination of both an RFQ and a rebunching drifttube unit inside a common cavity forming one single resonant RF-structure has been realized for the first time with this machine. The results of the beam measurements and questions about the beam dynamics simulations of such a combination have been investigated in detail with the code RFQSIM. | ||
| WEPCH118 | LORASR Code Development | 2194 |
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| LORASR is specialized on the beam dynamics design of Separate Function DTL's based on the 'Combined 0 Degree Structure (KONUS)' beam dynamics concept. The code has been used for the beam dynamics design of several linacs already in operation (GSI-HLI, GSI-HSI, CERN Linac 3, TRIUMF ISAC-I) or scheduled for the near future (Heidelberg Therapy Injector, GSI Proton Linac). Recent code development was focused on the implementation of a new PIC 3D FFT space charge routine, facilitating time-efficient simulations with up to 1 million macro particles routinely, as well as of tools for error study and loss profile investigations. The LORASR code was successfully validated within the European HIPPI Project activities: It is the Poisson solver benchmarking and the GSI UNILAC Alvarez section tracking comparison programme. The error study tools are a stringent necessity for the design of future high intensity linacs. The new LORASR release will have a strong impact on the design of the GSI FAIR Facility Proton Linac, as well as the transmission investigations on the IFMIF Accelerator. This paper presents the status of the LORASR code development and the benchmarking results. | ||
| WEPCH119 | Beam Performance with Internal Targets in the High-energy Storage Ring (HESR) | 2197 |
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The High-energy Storage Ring of the future International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt is planned as an antiproton synchrotron storage ring in the momentum range of 1.5 to 15 GeV/c. An important feature of HESR is the combination of phase space cooled beams and dense internal targets (e.g., pellet targets), which results in demanding beam parameter requirements for two operation modes: high luminosity mode with peak luminosities of up to 2·1032 cm-2 s-1, and high resolution mode with a momentum spread down to 10-5, respectively. The beam cooling equilibrium and beam loss with internal target interaction is analyzed. Rate equations are used to predict the rms equilibrium beam parameters. The cooling and intra-beam scattering rate coefficients are obtained from simplified models. Energy loss straggling in the target and the associated beam loss are analyzed analytically assuming a thin target. A longitudinal kinetic simulation code is used to study the evolution of the momentum distribution in coasting and bunched beam. The analytic expressions for the target induced momentum tail are found in good agreement with the simulation results.
*A. Lehrach et al. Beam Performance and Luminosity Limitations in the High-Energy Storage Ring (HESR), Nuclear Inst. and Methods in Physics Research, A44704 (2006). |
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| WEPCH120 | Simulation of 3D Space-charge Fields of Bunches in a Beam Pipe of Elliptical Shape | 2200 |
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| Recent applications in accelerator design require precise 3D calculations of space-charge fields of bunches of charged particles additionally taking into account the shape of the beam pipe. An actual problem of this kind is the simulation of e-clouds in damping rings. In this paper a simulation tool for 3D space-charge fields is presented where a beam pipe with an arbitrary elliptical shape is assumed. The discretization of the Poisson equation by the method of finite differences on a Cartesian grid is performed having the space charge field solved only in the points inside the elliptical cross-section of the beam pipe taking care of the conducting boundaries of the pipe. The new routine will be implemented in the tracking code ASTRA. Numerical examples demonstrate the performance of the solution strategy underling the new routine. Further tracking results with the new method are compared to established space-charge algorithms such as the FFT-approach. | ||
| WEPCH121 | 3D Space-charge Calculations for Bunches in the Tracking Code ASTRA | 2203 |
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| Precise and fast 3D space-charge calculations for bunches of charged particles are of growing importance in recent accelerator designs. One of the possible approaches is the particle-mesh method computing the potential of the bunch in the rest frame by means of Poisson's equation. In that, the charge of the particles are distributed on a mesh. Fast methods for solving Poisson's equation are the direct solution applying Fast Fourier Methods (FFT) and a finite difference discretization combined with a multigrid method for solving the resulting linear system of equations. Both approaches have been implemented in the tracking code ASTRA. In this paper the properties of these two algorithms are discussed. Numerical examples will demonstrate the advantages and disadvantages of each method, respectively. | ||
| WEPCH122 | 2D Wake Field Calculations of Tapered Structures with Different FDTD Discretization Schemes | 2206 |
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The continual performance improvement of particle accelerators requires advanced prediction of parasitic wake field effects, even in structures of comparatively weak influence like tapers. In the case of smooth tapered components, even well established codes like MAFIA* demonstrate strong discretization dependency of the results or solver instabilities, making them not reliable in such applications. Grid dispersion is assumed to generate this failure. In Ref.** an alternative discretization scheme is described, using a homogeneous rotated mesh intended to eliminate such grid dispersion effects. In order to study the dependence on the discretization applied, we use this scheme to calculate wake fields in prototype taper structures of rotational symmetry. Furthermore a comparison is provided with the results of a non-rotated mesh, MAFIA runs and - so far applicable - analytical approaches.
*MAFIA V4.107: CST GmbH, Bad Nauheimer Str. 19, D-64289 Darmstadt**R. Hampel et al. New discretization scheme for wake field computation in cylindrically symmetric structure. Proc. EPAC'04, pp 2559 |
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| WEPCH123 | Large Simulation of High Order Short Range Wakefields | 2209 |
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| We present a formalism for incorporating intra-bunch wake fields into particle-by-particle tracking codes, such as MERLIN and BDSIM. Higher order wake field effects are incorporated in a manner which is computationally efficient. Standard formulae for geometric, resistive and dielectric wake fields are included for various apertures, particularly those relevant for ILC collimators. Numerous examples are given. | ||
| WEPCH124 | BDSIM - Beamline Simulation Toolkit Based on Geant4 | 2212 |
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| BDSIM is a code that combines accelerator-style particle tracking with traditional Geant-style tracking based on Runge-Kutta techniques. This approach means that particle beams can be tracked efficiently when inside the beampipe, while also enabling full Geant4 processes when beam-particles interact with beamline apertures. Tracking of the resulting secondary particles is automatic. The code is described, including a new MAD-style interface and new geometry description, and key performance parameters are listed. | ||
| WEPCH125 | New Design Tools for a Cyclotron Central Region | 2215 |
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| A code that allows us to design the spiral inflector and the central region of the SCENT cyclotron was implemented. The code integrates the main equations of motion of a particle in an electromagnetic field and provides an useful interface to describe the geometry and the physical constraints of the inflector and the central region to be simulated. The mechanical drawings of the inflector and the central region is made using a standard CAD. These drawings are then imported in OPERA 3D to produce the maps of the electric and magnetic field. An application interface allows us to enter the emittance and the particles’ distributions to be transported through the inflector. An iterative process to design the central region was also developed and tested. | ||
| WEPCH126 | Issues in Modelling of Negative Ion Extraction | 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. | ||
| 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 | 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. | ||
| WEPCH128 | Virtual Accelerator as an Operation Tool at J-PARC 3 GeV Rapid Cycling Synchrotron (RCS) | 2224 |
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| We developed a virtual accelerator based on EPICS for 3 GeV Rapid-Cycle Synchrotron (RCS) in J-PARC. It is important to have an on-line model of optics parameters, such as tunes, Twiss parameters, dispersion function, at the commissioning stage in a high intensity proton machine. It gives a strong feedback for the RCS operation as a commissioning tool as well as for the studies of beam dynamics issues. Beam position monitors with finite resolutions, a transverse exciter to measure the betatron frequency, and a RF system with variable frequency to simulate off-momentum optics have been implemented into the system. The virtual accelerator system itself and some results of beam dynamics studies will be presented. | ||
| WEPCH130 | Analysis of Symmetry in Accelerating Structures with Group Theory | 2227 |
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Many rf cavities for modern accelerators have a variety of symmetry. There is a question as to what is the connection between the symmetry of a cavity and of its eigenmodes. This can be clarified* using the representation theory of groups. The geometric symmetry of a cavity can be expressed by a group of symmetry operations. The structure of this group can be represented by a set of matrices called representation. The group is associated with several irreducible representations which can express possible patterns of transformations under the symmetry operations. The irreducible representations are very suitable to express the symmetry of each eigenmode. This method can be used to improve the understanding of non-axially symmetric structures. In this paper, this method is first explained, and then, it is extended to the application of symmetric periodic structures.
*S. Sakanaka, Phys. Rev. ST Accel. Beams 8, 072002 (2005). |
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| WEPCH131 | Development of Numerical Code for Self-consistent Wake Field Analysis with Curved Trajectory Electron Bunches | 2230 |
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| Strongly interacting phenomena of electromagnetic radiation fields and ultra-relativistic electron is one of great interests in accelerator science such as in electron beam dynamics at the bunch compressor. The phenomena are described by time domain boundary value problem for the Lienard-Wiechert solutions. Authors develop a time domain boundary element method for self-consistent wake fields analysis of electromagnetic fields and charged particles. To use boundary integral equation for describing the electromagnetic fields, the time domain boundary value problems for the Lienard-Wiechert solution can be naturally formulated and we can simulate the wake fields phenomena with electron beam dynamics. In this paper, beam dynamics of curved trajectory electron bunches inside uniform beam tube are numerically simulated by using 2.5 dimension time domain boundary element technique. Various effects of closed beam tube for ultra-relativistic electron dynamics are considered comparing with the Lienard-Wiechert solutions in free space. | ||
| WEPCH132 | Design Study of Dedicated Computer System for Wake Field Analysis with Time Domain Boundary Element Method | 2233 |
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| Time domain boundary element method (TDBEM) has advantages of dispersion free calculations and modeling of curved beam trajectories in wake field analysis compared to conventional methods. These advantages give us powerful possibilities for analysis of beam dynamics due to CSR in bunch compressors of next-generation accelerators. On the other hand, the TDBEM also has a serious difficulty of large computational costs. In this paper, a dedicated computer system for wake field analysis with the TDBEM is proposed as one of solutions for high performance computing (HPC) technologies. Recent remarkable progress of LSI hardware design environments such as HDL compiler tools and large scale FPGAs enables us to make up computer hardware systems with very low cost in a short development period. The authors have been working in design studies of the TDBEM dedicated computer system on such LSI design environments. This paper presents a system design and VHDL simulations of a wake field analysis machine based on the TDBEM. | ||
| 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 | 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. | ||
| WEPCH136 | Monte Carlo Simulation Model of Internal Pellet Targets | 2239 |
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| We develop a numerical model of a pellet target and use it for Monte Carlo simulations of the interaction of a circulating beam with a pellet target. Real geometry details of the pellet beam and the beam are taken into account. We emphasize the role of tails of non-Gaussian distributions for transverse scattering and energy loss. These effects are especially important for simultaneous calculations of electron cooling, intrabeam scattering and target influence. Black-box algorithms for the generation of automatic nonuniform random variate distributions are used for the effective time averaging of scattering angle and energy loss distributions. | ||
| WEPCH137 | FAKTOR2: A Code to Simulate the Collective Effects of Electrons and Ions | 2242 |
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| A new code for computing the multiple effects of slowly moving charges is being developed. The basic method is electrostatic particle in cell. The underlying grid is rectangular and locally homogeneous. At regions of interest, e.g., where the beam is, or near material boundaries, the mesh is refined recursively. The motion of the macroparticles is integrated with an adapted timestep. Fast particles are treated with a smaller timestep, and particles in regions of fine grids are also treated with a fine timestep. The position of collision of particles with material boundaries is accurately resolved. Secondary particles are then created according to user-specified yield functions. | ||
| WEPCH138 | Simulations of Long-range Beam-beam Interaction and Wire Compensation with BBTRACK | 2245 |
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| We present weak-strong simulation results for the effect of long-range beam-beam collisions in LHC, SPS, RHIC and DAFNE, as well as for proposed wire compensation schemes or wire experiments, respectively. In particular, we discuss details of the simulation model, instability indicators, the effectiveness of compensation, the difference between nominal and PACMAN bunches for the LHC, beam experiments, and wire tolerances. The simulations are performed with the new code BBTRACK. | ||
| WEPCH139 | WISE: An Adaptative Simulation of the LHC Optics | 2248 |
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| The LHC beam dynamics requires a tight control of the magnet field quality and geometry. As the production of the magnets advances, decisions have to be made on the acceptance of possible imperfections. To ease decision making, an adaptative model of the LHC optics has been built, based on the current information available (e.g. magnetic measurements at warm or cold, magnet allocation to machine slots) as well as on statistical evaluations for the missing information (e.g. magnets yet to be built, measured, or for non-allocated slots). The uncertainties are included: relative and absolute measurement errors, warm-to-cold correlations for the fraction of magnets not measured at cold, hysteresis and power supply accuracy. A pre-processor generates instances of the LHC ring for the MADX program, with the possibility of selecting various error sources. A post-processor computes ranges for relevant beam optics parameters and distributions. This approach has been applied to the expected beta-beating, to the possible impact of permeability issues in some quadrupole collars, to the geometrical displacements of the multipolar correctors and to prioritize the magnetic measurement programme. | ||
| WEPCH140 | Recent Improvements of PLACET | 2251 |
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| The tracking code PLACET is used to simulate the beam transport in linear colliders from the damping ring to the interaction point and beyond. Recent improvements of the code are presented. They include the possibility to simulate bunch compressors and to use parallel computer systems. | ||
| WEPCH141 | Accelerator Physics Code Web Repository | 2254 |
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| In the framework of the CARE HHH European Network, we have developed a web-based dynamic accelerator-physics code repository. We describe the design, structure and contents of this web repository, illustrate its usage, and discuss our future plans. | ||
| WEPCH143 | Electron Linac Based e,X-radiation Facility | 2257 |
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| In a number of technologies based on high-current electron accelerators bremsstrahlung is generated in the interaction of the beam with the irradiated object. Thus, in addition to the electron radiation, the bremsstahlung may be used for carring out of different technolodgical programs (e,X-facility). A method for the numerical analysis and optimization of the radiation characteristics of such installation is proposed. The accelerator beam track, starting from the electron source and up to output devices is considered as a single multicomponent target consisting of the layers of different materials. The thickness of each layer is measured in the generalized units of the "stopping length". Using the method of simulation based on the PENELOPE/2001 system the characteristics of the mixed e,gamma-radiation field (energy yield of electrons, photons and their ratio) as function of the stopping length for actual or anticipated version of output equipment can be calculated. To illustrate the method, the parameters of the beam path of the NSC KIPT Linacs used as e,X-facilities was analyzed. | ||
| WEPCH144 | CSR Effects in a Bunch Compressor: Influence of the Transverse Force and Shielding | 2260 |
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We study the influence of CSR on particle bunches traveling on arbitrary planar orbits between parallel conducting plates with a fixed "vertical" charge distribution. Our goal is a numerical solution of the 2 degree-of-freedom Vlasov-Maxwell equations. This provides simulations with lower numerical noise than the macroparticle method and allows the study of emittance degradation and microbunching. As reported*, we calculate the fields excited by the bunch in the lab frame using a new formula that leads to a simplification. The Vlasov equation is integrated in the beam frame interaction picture using the method of local characteristics. The transformation between traditional beam frame and lab frame coordinates is carefully treated. Here we report on our implementation of the algorithm in the context of a chicane bunch compressor**, where the strong correlation between phase space variables requires an adaptive grid. In particular, we present a complete analysis (moments + reduced densities) of the bunch evolution under the fields produced by the unperturbed bunch density. Finally, our progress on the fully self-consistent case is discussed.
* Vlasov treatment of coherent synchrotron radiation from arbitrary planar orbits, Nucl. Instr. Meth. Phys. Res. A, in press.** ICFA Beam Dynamics Mini-Workshop on CSR, Berlin-Zeuthen, 2002. See http://www.desy.de/csr. |
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| WEPCH145 | Particle Tracking and Simulation on the .NET Framework | 2263 |
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Particle tracking and simulation studies are becoming complex. In addition to the sophisticated graphics, interactive scripting is becoming popular. A compatibility with the control system requires network and database capabilities. It is not a trivial task to fulfill various requirements without sacrificing the runtime performance. We evaluate the use of .NET to solve this issue by converting a C++ code Goemon* that is an object-oriented version of Tracy developed at ALS. The portability to other platforms will be mentioned in terms of Mono.
*H. Nishimura, PAC'01, Chicago, July 2001, p.3066. |
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| WEPCH146 | Intrabeam Scattering Studies for the ILC Damping Rings Using a New Matlab Code | 2266 |
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A new code to calculate the effects of intrabeam scattering (IBS)has been developed in Matlab based on the approximation suggested by K. Bane*. It interfaces with the Accelerator Toolbox** but can also read in lattice functions from other codes. The code has been benchmarked against results from other codes for the ATF*** that use this approximation or do the calculation in a different way. The new code has been used to calculate the emittance growth due to intrabeam scattering for the lattices currently proposed for the ILC Damping Rings, as IBS is a concern, especially for the electron ring. A description of the code and its user interface, as well as results for the Damping Rings, will be presented.
*K. Bane, in Proceedings of EPAC2002, p.1443. **A. Terebilo, Accelerator Toolbox for MATLAB, SLAC-PUB-8732 and www-ssrl.slac.stanford.edu/at/. ***K. Kubo et al. PhysRevST AB.8.081001 (2005). |
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| WEPCH147 | Simulations of Electron Effects in Superconducting Cavities with the VORPAL Code | 2269 |
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Modeling the complex boundaries of superconducting radio frequency (SRF) accelerating cavities on a Cartesian grid is a challenge for many Finite Difference Time Domain (FDTD) electromagnetic PIC codes. The simulation of such cavities require conformal (curve fitting) boundaries. Modeling the full cavity including couplers and ports is fundamentally a three dimensional problem requiring capability to run in parallel on large numbers of processors. We have recently added conformal boundaries using the method of Zagorodnov* to the plasma simulation code VORPAL. Using this higher order boundary algorithm and the surface physics package TxPhysics, we have begun studies of self-consistent electron effects in SRF cavities. We have modeled the beam excitation of cavity modes and the effects of electron multipacting. Results from these studies will be presented using the new user friendly visualization tool that now ships with VORPAL.
*I. A. Zagorodnov et al. “A uniformly stable conformal FDTD-method in Cartesian grids,” International Journal of Numerical Modeling 16, 127 (2003). |
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| WEPCH148 | Computing TRANSPORT/TURTLE Transfer Matrices from MARYLIE/MAD Lie Maps | 2272 |
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| Modern optics codes often utilize a Lie algebraic formulation of single particle dynamics. Lie algebra codes such as MARYLIE and MAD offer a number of advantages that makes them particularly suitable for certain applications, such as the study of higher order optics and for particle tracking. Many of the older more traditional optics codes use a matrix formulation of the equations of motion. Matrix codes such as TRANSPORT and TURTLE continue to find useful applications in many areas where the power of the Lie algebra approach is not necessary. Arguably the majority of practical optics applications can be addressed successfully with either Lie algebra or matrix codes, but it is often a tedious exercise to compare results from the two types of codes in any detail. Differences in the choice of dynamic variables, between Lie algebra and matrix codes, compounds the comparison difficulties already inherent in the different formulations of the equations of motion. This paper summarizes key relationships and methods that permit that direct numerical comparison of results from MARYLIE and MAD with those from TRANSPORT and TURTLE. | ||
| WEPCH149 | PBO LAB (tm) Tools for Comparing MARYLIE/MAD Lie Maps and TRANSPORT/TURTLE Transfer Matrices | 2275 |
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| Particle optics codes frequently utilize either a Lie algebraic formulation or a matrix formulation of the equations of motion. Examples of codes utilizing the Lie algebra approach include MARYLIE and MAD, whereas TRANSPORT and TURTLE use the matrix formulation. Both types of codes have common application to many particle optics problems. However, it is often a very tedious exercise to compare results from the two types of codes in any great detail. As described in a companion paper in these proceedings, differences in the choice of phase space variables, as well as the inherent differences between the Lie algebraic and matrix formulations, make for unwieldy and complex relations between results from the two types of codes. Computational capabilities have been added to the PBO Lab software that automates the calculation of transfer matrices from Lie maps, and that converts phase space distributions between the different representations used by the codes considered here. Graphical and quantitative comparison tools have been developed for quick and easy visual comparisons of transfer maps and matrices. | ||
| WEPCH150 | The Accelerator Markup Language and the Universal Accelerator Parser | 2278 |
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| A major obstacle to collaboration on accelerator projects has been the sharing of lattice description files between modeling codes. To address this problem, a lattice description format called Accelerator Markup Language (AML) has been created. AML is based upon the standard eXtensible Markup Language (XML) format; this provides the flexibility for AML to be easily extended to satisfy changing requirements. In conjunction with AML, a software library, called the Universal Accelerator Parser (UAP), is being developed to speed the integration of AML into any program. The UAP is structured to make it relatively straightforward (by giving appropriate specifications) to read and write lattice files in any format. This will allow programs that use the UAP code to read a variety of different file formats. Additionally this will greatly simplify conversion of files from one format to another. Currently, besides AML, the UAP supports the MAD lattice format. | ||
| WEPCH152 | Comment on Healy's Symplectification Algorithm | 2281 |
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For long-term tracking, it is important to have symplectic maps for the various electromagnetic elements in an accelerator ring. While many standard elements are handled well by modern tracking programs, new magnet configurations (e.g., a helical dipole with a superimposed solenoid) are being used in real accelerators. Transport matrices and higher terms may be calculated by numerical integration through model-generated or measured field maps. The resulting matrices are most likely not quite symplectic due to numerical errors in the integrators as well as the field maps. In his thesis*, Healy presented a simple algorithm to symplectify a matrix. This paper presents a discussion of limitations of this method.
*L. M. Healy, "Lie Algebraic Methods for Treating Parameter Errors in Particle Accelerators", Doctoral Thesis. University of Maryland, unpublished (1986). |
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| WEPCH153 | Symplectic Interpolation | 2284 |
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| It is important to have symplectic maps for the various electromagnetic elements in an accelerator ring. For some tracking problems we must consider elements which evolve during a ramp. Rather than performing a complicated numerical integration for every turn, it should be possible to integrate the trajectory for a few sets of parameters, and then interpolate the transport map as a function of one or more parameters, such as energy. We present two methods for interpolation of symplectic matrices as a function of parameters: one method is based on the logarithm of the matrix, and the other is based on the related but simpler Healy symplectification method. | ||
| WEPCH154 | SPS Access System Upgrade | 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. | ||
| WEPCH155 | Tune-stabilized Linear-field FFAG for Carbon Therapy | 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. | ||
| WEPCH156 | CERN Safety Alarms Monitoring System (CSAM) | 2293 |
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| The CERN Safety Alarms Monitoring (CSAM) system is designed to aquire and transmit reliably to the CERN Fire Brigade all the alarms generated by a large number of safety alarm equipment distributed around the sites and in the underground. The quality and accuracy of the information provided by CSAM is crucial to permit a quick and efficient intervention by the Fire Brigade. The CSAM projet was launched in 1999 to replace the previous alarm system which used obsolete technology and operator devices. The new system is in operation since 2005 and 2/3 of all alarm equipement on the CERN sites are now handled by the new system. The migration/installation process is is expected to terminate in May 2006. This paper presents the system architecture, the deployment process and the return of experience in the accelerator environment. | ||
| WEPCH157 | Design and Beam Dynamics Simulation for the Ion-injector of the Austrian Hadron Therapy Accelerator | 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. | ||
| WEPCH158 | Status of the Hadrontherapy ETOILE-Project in Lyon | 2299 |
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| The ETOILE project is the French program for carbon ion beams in cancer treatment. It is now in the final phase. However its development is not only aiming at the building of a medical facility, around the project a broad set of medical and scientific programs have been initiated. The project has been supported by the University of Lyon and extended to the Rhône-Alpes Region and then gained a national visibility with governmental recognition. Many studies have been financed by ETOILE: in beam PET with new solutions, organ motion modelization, tumor cell radioresistance, medico-economical simulation and epidemiological previsions. The facility will be able to produce carbon ion beams and protons. Three treatment rooms are planned, two with horizontal beams and one with an isocentric gantry. The facility will be build in Lyon, through a process using as much as possible well established technology with the other facilities in Europe. The cost will be around 105 M€ afforded by loans and subventions. The subventions are funded from the Rhône-Alpes Region, the city of Lyon and the ministries of Health and Research. The running cost of the centre, for one thousand patients per year, is estimated to be 21 M€. | ||
| WEPCH159 | Accelerator Systems for Particle Therapy | 2302 |
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Danfysik and Siemens have entered a cooperation to market and build Particle Therapy* systems for cancer therapy. The systems are based on the experience from GSI together with a novel design of a synchrotron and Siemens experience in oncology. The accelerator systems will include an injector system (7 MeV/u proton and light ions), a synchrotron and a choice of fixed-angle horizontal and semi-vertical beamlines together with gantry systems. The slowly extracted beam will cover the energy ranges of 48-250 MeV for protons and 88-430 MeV/u for carbon ions. The extraction time will be up to 10s with intensities well beyond the needs of scanning beam applications. We will describe the layout of such a system and present details on some of the subsystems.
*Particle Therapy is a work in progress and requires country-specific regulatory approval prior to clinical use. |
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| WEPCH160 | A Novel Proton and Light Ion Synchrotron for Particle Therapy | 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. | ||
| WEPCH161 | The FFAG R&D and Medical Application Project RACCAM | 2308 |
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The RACCAM project (Recherche en ACCelerateurs et Applications Medicales) has recently obtained fundings, extending over three years (2006-2008), from the French National Research Agency (ANR). RACCAM is a tripartite collaboration, involving (i) the CNRS Laboratory IN2P3/LPSC, (ii) the French magnet industrial SIGMAPHI, and (iii) the nuclear medecine Departement of Grenoble Hospital. The project concerns fixed field alternating gradient accelerator (FFAG) research on the one hand, and on the other hand their application as hadrontherapy and biology research machines. RACCAM's goal is three-fold, (i) participate to the on-going international collaborations in the field of FFAGs and recent concepts of "non-scaling" FFAGs, with frames for instance, the Neutrino Factory (NuFact) and the EMMA project of an electron model of a muon FFAG accelerator, (ii) design, build and experiment a prototype of an FFAG magnet proper to fulfil the requirements of rapid cycling acceleration, (iii) develop the concepts, and show the feasibility, of the application of such FFAG beams to hadrontherapy and to biology research.
*CEA/DAPNIA and IN2P3/LPSC **IN2P3/LPSC ***Grenoble University Hospital ****SIGMAPHI |
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| WEPCH162 | Magnet Simulations for Medical FFAG | 2310 |
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| Studies have been undertaken concerning magnet design in the frame of the RACCAM FFAG project (this conference). This contribution reports on the objectives of the project in that matter, on the working methods and calculation tools developments, magnetic field modeling and simulations, and on the present status of this work. | ||
| WEPCH164 | High Power RF Tests of the First Module of the TOP Linac SCDTL Structure | 2313 |
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| The TOP Linac (Oncological Therapy with Protons), under development by ENEA and ISS, is a sequence of three pulsed (5 microseconds, 300 Hz) linear accelerators: a 7 MeV, 425 MHz RFQ+DTL (AccSys Model PL-7), a 7-65 MeV, 2998 MHz Side Coupled Drift Tube Linac (SCDTL), and a 65-200 MeV, variable energy 2998 MHz Side Coupled Linac (SCL). The first SCDTL module structure, composed by nine DTL tanks coupled by eight side cavities, has been built. Low power RF measurements have shown good field uniformity and stability along the axis. The structure has been tested with a 1 - 4 MW power RF. Results of low and high power tests are reported and discussed. | ||
| WEPCH165 | A Nonlinear Transport Line for the Optimization of F18 Production by the TOP Linac Injector | 2316 |
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| The injector of the TOP Linac (Oncological Therapy with Protons), under development by ENEA and ISS, consists of a 7 MeV, 425 MHz RFQ+DTL (AccSys Model PL-7). It is actually in operation at ENEA-Frascati Laboratories for the production of the positron-emitting radionuclide F18 for PET analyses by an intense proton beam (8 - 10 mA, 50 - 100 μs, 30 - 100 Hz). At the exit of the injector, the beam is guided through a magnetic channel to a target composed by a thin chamber (0.5 mm thick and 1-inch diameter) containing water enriched with O18. Recently, to the original quadrupole transport channel, a non-linear magnet system using octupoles has been added in order to flatten the proton beam distribution and optimize the radioisotope production. In the paper the details of the octupole design and beam dynamic study and the first measurements results are presented. | ||
| WEPCH166 | Beam Test of Thermionic Cathode X-band RF-gun and Linac for Monochromatic Hard X-ray Source | 2319 |
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| A compact hard X-ray source based on laser-electron collision is proposed. The X-band linac is introduced to realize a very compact system. 2MeV electron beam with average current 2μampere at 10 pps, 200 ns of RF pulse is generated by a thermionic cathode X-band RF-gun. Beam acceleration and X-ray generation experiment by the X-band beam line are under way. | ||
| WEPCH167 | Study of Scatterer Method to Compensate Asymmetric Distribution of Slowly Extracted Beam at HIMAC 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. | ||
| WEPCH168 | Development toward Turn-key Beam Delivery for Therapeutic Operation at HIMAC | 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. | ||
| WEPCH169 | Alternating Phase Focused IH-DTL for Heavy-ion Medical Accelerators | 2328 |
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Tumor therapy using HIMAC has been performed at NIRS since June 1994. With the successful clinical results over more than ten years, a number of projects to construct these complexes have been proposed over the world. Since existing heavy-ion linacs are large in size, the development of compact linacs would play a key role in designing compact and cost-effective complexes. Therefore, we developed an injector system consisting of RFQ and Interdigital H-mode (IH) DTL having the frequency of 200 MHz. The injector system can accelerate carbon ions up to 4.0 AMeV. For the beam focusing of IH-DTL, the method of Alternating Phase Focusing (APF) was employed. With the IH structure and rather high frequency, the cavity size is compact; the radius is 0.4 m, and lengths of RFQ and IH-DTL are 2.5m and 3.5m respectively. The fabrication of RFQ was completed, and we succeeded to accelerate carbon ions with satisfactory performances. For IH-DTL, the full-scale model was first fabricated. With the encouraging result* of its electric field measurement, we constructed IH-DTL and beam acceleration tests will be performed in March 2006. We will present the performances of the entire injector system.
*Y. Iwata et al., Nucl Instr. & Meth in Phys. Res. A (submitted). |
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| WEPCH170 | Development of Intensity Control System with RF-knockout Extraction at the HIMAC Synchrotron | 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. | ||
| WEPCH172 | Electron Beam Pulse Processing toward the Intensity Modified Radiation Therapy (IMRT) | 2334 |
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| Radiation therapy attracts attention as one of the cancer therapies nowadays. Toward the next generation of the intensity modified radiation therapy (IMRT), the processing of electron beam pulse is studied using a photo cathode RF gun linac. Accelerated electron pulses will be converted to x-ray pulses by a metal target bremsstrahlung method or by a laser inverse Compton scattering method. Recently, the radiation therapy of cancer is developing to un-uniform irradiation as IMRT. A photo cathode RF gun is able to generate a low emittance electron beam pulse using a laser light pulse. We thought that a photo cathode RF gun can generate intensity and shape modified electron beam by processing of incident laser light. Because of a low emittance, an electron pulse is able to accelerate keeping shape. Electron beam processing by photo masks in incident optical system and generated beams are reported here. Images on photo masks were transported to a cathode surface by optical relay imaging. Beams were monitored by Desmarquest (Cr:Al2O3) luminescence. Spatially separation of a spot to a spot is about 0.3mm. Modified electron beam has fine spatial resolution. | ||
| WEPCH173 | The Performance of Double-grid O-18 Water Target for FDG Production | 2337 |
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| The main stream of our study about the target is increasing the lifetime of the target windows. Mainly we conduct our study to increase the cooling performance and secondly about the structural design of the targets and target window foils. We already had developed and had published the results of our research about O-18 double-grid water target, which had installed on our 13 MeV cyclotron KIRAMS-13. The beam size of the accelerated proton was 9 mm*18 mm (0.35 in * 0.7 in). The double-grid target shows relatively low pressure during irradiation and good yield of F-18. The average yield of F-18 after irradiation was more than 1 Ci at 12.5 MeV , around 26 μA. Additionally, we are conducting new research for new techniques to increase the performance of low energy double-grid target and a new state-of-the-art pleated double foil target. | ||
| WEPCH175 | Design of 12 MEV RTM for Multiple Applications | 2340 |
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| Design of a compact 12 MeV race-track microtron (RTM) is described. The results of operating wavelength choice, accelerating structure and end magnets optimization and beam dynamics simulation are represented. Use of a C-band linac and rare earth permanent magnet end magnets permit to design RTM, which is more compact and more effective as compared with the same energy circular microtron or linac. Electron beam with energy 4-12 MeV in 2 MeV step can be extracted from RTM. The estimated pulsed RF power required for feeding the linac is about 800 kW, total mass of accelerator is less than 40 kg and its dimensions are about 500x200x110 mm3. | ||
| WEPCH177 | Conception of Medical Isotope Production at Electron Accelerator | 2343 |
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| A photonuclear method with the use of high-energy bremsstrahlung (Eg>8 MeV) of high intensity (>= 1004 W/cm2) provides a possibility of the ecologically safe production of a number of isotopes for nuclear medicine. The conditions of generation of the radiation field having such characteristics as well as the features of photonuclear production of W-181,Pd-103, Cu-67 and other radionuclides are considered in the report. At the initial stage the study of the isotope production is performed by means of the computer simulation in a simplified 2D geometry of the Linac output devices. The code on the base of the PENELOPE/2001 program system supplemented with the data on the excitation functions of the corresponding reactions was developed. The dependences of the isotope yield (gross and specific activity) on the electron energy (30…45 MeV), as well as, the data on absorbed energy of radiation in the targets of natural composition are represented. The experimental results confirm the data of modelling. Main trends of realization of the photonuclear method for isotope production and the necessary conditions of the increase of its yield are analysed. | ||
| WEPCH178 | Simulation Study of Compact Hard X-ray Source via Laser Compton Scattering | 2346 |
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| The compact hard X-ray source via laser Compton scattering between high intensity electron beam and high power laser beam was developed at FESTA (The Femtosecond Technology Research Association) project in collaboration between AIST and SHI. According to completion of the project in March 2005, the compact hard X-ray source is being transferred from FESTA to AIST to upgrade and to apply the system to biological and medical uses. Our system consists of a laser-driven photocathode rf gun, two 1.5m-long S-band accelerator structures and a high power Ti:Sa Laser system. This system can generate a hard X-ray pulse which has variable energy of 12 keV – 33 keV with narrow bandwidth by changing electron energy and collision angle. Maximum X-ray photon yield at FESTA was accomplished about 107photons/s (@10Hz, MAX 33keV) in case of 165 degree collision angle. In the next phase, we are planning to make the total system much compact using X-band or C-band accelerator structures with permanent magnets. We have carried out the numerical simulations to investigate the possibility of these compact systems. In this conference, we will talk about results of the simulations and future plans. | ||
| WEPCH179 | The Indiana University Proton Therapy System | 2349 |
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The Midwest Proton Radiotherapy Institute (MPRI)was designed by the Indiana University Cyclotron Facility (IUCF)to deliver proton radiation treatment to patients with solid tumors or other diseases susceptible to radiation. The IUCF Proton Therapy System (PTS)has five unigue subsystems to perform the radiation treatment; Beam Delivery, Dose Delivery, Patient Positioning and Treatment Control systems. The MPRI Clinic began operations in 2003 with a single Fixed Horizontal Beam Line (FHBL)treatment room and is being expanded to include two additional treatment rooms utilizing modified IBA* 360 degree rotating gantry systems. The Gantry nozzles use a beam wobbling and energy stacking system to produce the lateral and longitudinal beam distributions required for patient treatment. A treatment control system** provides a single user interface to deliver and monitor Proton Therapy treatment. This paper will present an brief overview of the Proton Therapy Facility, the properties and examples of the beam performance of the unique Nozzle design, and a summary of the facility beam operations.
* Ion Beam Applications, Inc, Belgium ** Design of a Treatment Control System for a Proton Therapy Facility, Joe Katuin, these proceedings |
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| WEPCH180 | A Dramatically Reduced Size in the Gantry design for the Proton-Carbon Therapy | 2352 |
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| Gantries in the proton/carbon cancer therapy machines represent the major cost and are usually very large. This report explains a new way for the gantry design. The size and cost of the gantries are reduced, and their use is simplified by using the fixed magnetic field. The "new" gantry is made of a very large momentum acceptance non-scaling Fixed Field Alternating Gradient (FFAG) quarter and half arc beam lines. The gantry is made of combined function magnets with a very strong focusing and small dispersion function. Additional magnets with a fast response are required to allow adjustments of the beam position for different energies at the beginning of the gantry. The strong focusing magnets following the gantry have to be adjustable as well to provide the required spot size. The adjustable dipoles provide the radial scanning. The fixed field combined function magnets could be made of small permanent magnets for the proton machine, or of the high temperature superconductors or superconductors for the carbon machine, reducing dramatically the size. | ||
| WEPCH181 | Ion Implantation Via Laser Ion Source | 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. | ||
| WEPCH182 | Design of 9.4 GHz 950 keV X-band Linac for Nondestructive Testing | 2358 |
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| Mobile "suit-case-sized" x-band (9.4GHz) 950 keV linac is designed for applications of nondestructive testing (NDT). Conventional device for the purpose is the S-band linac, but its drawback is a rather large device-size, large electron beam spot size of about 3 mm and lack of spatial resolution. We aim to realize the smaller spot size about 500 micro-m by a low emittance beam. The proposed system consists of the 9.4 GHz magnetron, modulator, thermionic RF electron gun and 9.4 GHz x-band linac and metal target for x-ray generation. The energy at the gun is 20 keV, and the final energy becomes 950 keV. Now, we are designing the linac structure of the pai/2 mode and analyzing the electromagnetic field (EMF) by SUPERFISH. At this time, we finish analyzing EMF of regular cavity cells and we are analyzing EMF of total accelerating tube. We have finished the detailed RF design. Further, we are also performing the design of the pai mode and going to discuss the advantages and drawbacks between them. Construction of the RF supplying system is underway. The detailed design parameters and updated status of the construction are presented at the spot. | ||
| WEPCH183 | Enhancement of Mechanical Properties of High Chromium Steel by Nitrogen Ion Implantation | 2361 |
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| This article reports the study of mechanical properties of high chromium steel after N-ion implantation. The samples are implanted with 120keV N-ion at doses ranging from 1x1017ions/square cm to 4x1018ions/square cm. Mechanical properties of implanted samples are compared with those of Cr-plated samples. The compositions of the N-ion implanted layer were measured by Auger electrons spectroscopy(AES). Their mechanical properties as a function of N-ion doses were characterized by nano-indentation, sliding and impact wear tests. The results reveal that the hardness and mechanical properties of ion implanted samples were found to depend strongly on the ion doses. The hardness of the N-ion implanted sample with 2x1018ions/? was measured to be approximately 9 GPa, which is approximately 2.3 times higher than that of un-implanted sample (H=3.8 GPa). Also wear properties of N-ion implanted samples with 2x1018ions/? were largely improved ;compared to the Cr-plated samples, the width of wear track and friction coefficient developed on the N-ion implanted samples are about 60% and 40% smaller, respectively. | ||
| WEPCH184 | Mechanical Properties of WC-Co by Nitrogen Ion Implantation: Improvement of Industrial Tools | 2364 |
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| Ion implantation of WC-Co has been widely investigated for the improvement of wear resistance, but rarely for friction behavior. Although friction is closely associated with wear, more factors influence friction than wear, and low wear does not generally lead to low friction w6x. Therefore, we focus our study on the effects of ion implantation on the mechanical properties in WC-Co cermets, with particular interest in tool industry applications. | ||
| WEPCH186 | Present Status of FFAG Accelerators in KURRI for ADS Study | 2367 |
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| KART (Kumatori Accelerator driven Reactor Test) project is in progress at the Kyoto University Research Reactor Institute (KURRI) since fiscal year 2002. We are now constructing a 150 MeV proton FFAG accelerator complex as a neutron production driver for this project. The whole of this FFAG complex is expected to be in the test operation around the spring in 2006. The developments and the current status of this accelerator complex, including the current status of this project, will be presented. | ||
| WEPCH187 | A Compact 5 MeV, S-band, Electron Linac Based X-ray Tomography System | 2370 |
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| The availability of commercial X-ray tubes made of radiography and tomography two of the most used non-destructive testing techniques both in industrial and cultural heritage fields. Nevertheless, the inspection of heavy materials or thick objects requires X-ray energies larger than the maximum energy provided by commercial X-ray tubes (600 kV). For this reason, and owing to the long experience of the INFN-Gruppo Collegato di Messina in designing and assembling low energy electron linacs, at the Dipartimento di Fisica, Universita di Messina, a 5 MeV electron linac based X-ray tomographic system has been developed. The X-ray source, properly designed by means of the MCNP-4C2 code, provides a 16 cm diameter X-ray spot at the sample position and a beam opening angle of about 3.6 degree. The image acquisition system consists of a CCD camera (Alta Apogee E1, 768x512 pixel) and a GOS scintillating screen. Preliminary radiographies and tomographies showing the high quality performances of the tomographic system have been acquired. Finally, the compactness of the linac, is one of the advantages of this system that could be used for in situ inspections when huge structures have to be tested | ||
| WEPCH188 | Compact Picosecond Pulse Radiolysis System Using Photo-cathode RF Gun | 2373 |
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| A very compact picosecond pulse radiolysis system has been installed and operated at Waseda University. The system is composed of a laser photo-cathode RF gun as the pump source and stable Nd:YLF laser as the white light source to probe the reaction in the picosecond region. The white light generation is performed by the non-linear effect of intense laser light with the wavelength of 1047 nm into the water cell. The experimental results with the time resolution of 18 ps by examining the time profile of hydrated electron have been obtained. The system configuration will be also presented at the conference. | ||
| WEPCH189 | Design of the 20 MeV User Facilities of Proton Engineering Frontier Project | 2376 |
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| The user facilities of PEFP (Proton Engineering Frontier Project) was designed. It is composed of two beamlines at the first stage and has possibility of expansion to five beamlines. One is low flux beamline for the technology developments in the fields of biological and space sciences and the other is high flux beamline for the utilization in the fields of nano and material sciences. The flux density is 1E+8~1E+10 protons/cm2-sec and 1E+10~1E+13 protons/cm2-sec each. The available energy range is 5~20MeV and the irradiation area is larger than 10cm in diameter with uniformity more than 90% for both. The specifications of these beamlines mentioned above were decided on the basis of result of user demand survey and operation experience of 45MeV proton beam test beamline installed at the MC-50 cyclotron of KIRAMS (Korea Institute of Radiological and Medical Science). The key components of these beamlines are bending magnets, magnetic quadrupole doublet or triplet, collimators, scanning magnets, target stage with water cooling system, degrader for energy control, scattering foils for flux control, etc. The beam optics was calculated using TRANSPORT and TRACE 3D simulation code. | ||
| WEPCH190 | A Ridge Filter for 36 MeV Proton Beam Applied to BT and ST | 2379 |
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| We designed a ridge filter to obtain a uniform depth-dose distribution as well as to deliver high linear energy transfer along the depth of a target for 36MeV proton beam. Aluminum was chosen as the material of the filter to reduce the radioactivity induced by proton irradiation. The designed ridge filter has a continuous cross-sectional line shape of ridges so that the smoothly varying depth-dose distribution can be maintained before the distal fall-off for lower proton energy than 36MeV. The height of the ridge is 6 mm, its period is also 6 mm and the minimum thickness is 0.3 mm. A Monte Carlo simulation code, MCNPX 2.5.0., was used to calculate the dose distributions. The width of the calculated uniform dose region was 11 mm for 36MeV proton beam in a water-equivalent sample. | ||
| WEPCH191 | The Design and Manufacture of a 300 keV Heavy Ion Implanter for Surface Modification of Materials | 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. | ||
| WEPCH192 | Compact Electron Linear Accelerator RELUS-5 for Radiation Technology Application | 2385 |
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| The electron linear accelerator for radiation technology application is designed to meet the following main requirements: 3-5 MeV energy, 3-6 microsecond pulse width, and 1 kW average beam power. The accelerating system is a 0.5 m long S-band standing wave on-axis coupled biperiodic structure. A 35-40 kV electron gun with spherical cathode is used as the injector. The RF generator is a 2.5 MW peak power 4 kW average power magnetron. The generated frequency is stabilized by a high Q-factor accelerating system connected into feed-back of the magnetron. The magnetron is fed by a compact 45-55 kV IGBT based modulator. The accelerator is controlled through a PLC-based control system. | ||
| WEPCH194 | Complex for X-ray Inspection of Large Containers | 2388 |
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| The X-ray inspection complex is intended for non-intrusive inspection of large containers in the seaport. The complex has been developed, manufactured, and tested. To provide two projections of irradiated container and ensure reliable inspection, the complex includes two sets each containing self-shielded X-ray source and L-shaped detector array. The X-ray source includes electron linear accelerator with 7.3 MeV energy, conversion target, local radiation shielding, and alignment means. The accelerator uses standing wave bi-periodic structure fed by magnetron generator with 2.8 GHz frequency. It provides intensive electron beam without application of external magnetic field for the beam focusing. This feature makes it possible to use massive local radiation shielding made from iron. The radiation shielding provides large attenuation of scattered X-rays and ensures the radiation safety for personnel as well as high sensitivity of detecting system and good penetrability of the complex. | ||
| WEPCH195 | Status of the Russian Accelerator Mass Spectrometer Project | 2391 |
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| The status of the first Russian accelerator mass spectrometer being developed at BINP is described. The scheme of the spectrometer includes two types of ion sources (sputter and gaseous ones), electrostatic tandem accelerator with accelerating voltage up to 2 MV and magnesium vapors stripper and also includes the high-energy and low-energy beam lines with analyzers. The results of the experiments with the ion beams will be given. |