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MOYBPA01 | LHC Progress and Commissioning Plans | LHC, injection, dipole, luminosity | 14 | ||||
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The LHC at CERN is in its final installation phase, and the first tests with beam are planned for part of the machine for the end of 2006. The commissioning of the full machine with beam is planned for summer 2007. The talk summarizes the current status of the LHC installation and the strategy for obtaining an optimum hardware configuration. In a second part the talk outlines the main milestones for the hardware and beam commissioning and presents estimates for the expected performance levels for the commissioning phase with beam.
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Transparencies
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MOPCH006 | Beam Adaptation at the Infrared FEL, CLIO | undulator, FEL, electron, simulation | 56 | ||||
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The infrared free-electron laser CLIO is tunable from 3 to 150 5m by operating its driver RF linear accelerator between 50 and 12 MeV. This is the largest spectral range ever obtained with a single optical cavity. We have studied the electron beam transverse adaptation in the FEL undulator throughout the spectral and energy range. Each beam dimension is measured by a moving wire whose temperature dependant resistivity is monitored. The results are compared with simulations computed with the TRANSPORT code.
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MOPCH013 | Slice Emittance Measurements at FLASH | emittance, DESY, RF-structure, CSR | 77 | ||||
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The SASE process in Free Electron Lasers mainly depends on time-sliced parameters of charge density, energy spread and transverse emittance. At the VUV-FEL at DESY, electron bunches are compressed longitudinally in two magnetic chicanes in order to achieve high peak currents. The compression causes considerabe variations in slice emittance along the bunches. The vertically deflecting rf-structure LOLA, which is in operation at the VUV-FEL since early 2005, allows to resolve longitudinal variations in horizontal slice width for single bunches. The horizontal slice emittances can be determined by additionally varying the strengths of the quadrupoles upstream of LOLA. Results of slice emittance measurements using different bunch compression schemes are presented.
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MOPCH049 | Trajectory Stability Modeling and Tolerances in the LCLS | LCLS, linac, undulator, CSR | 151 | ||||
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To maintain stable performance of the Linac Coherent Light Source X-ray Free-electron laser, one has to control undulator trajectory stability to a small fraction of the rms beam size. BPM based feedback loops running at 120 Hz will be effective in controlling jitter at low frequencies less than a few Hz. On the other hand, linac and injector stability tolerances must control jitter at higher frequencies. In this paper, we study the possible sources of such high frequency jitter, including: 1) steering coil current regulation; 2) quadrupole (and solenoid) transverse vibrations; 3) quadrupole (and solenoid) current regulation in presence of typical 200-micron misalignments; 4) charge jitter coupling to RF cavity transverse wakefield due to alignment errors; and 5) bunch length jitter coupling to Coherent Synchrotron Radiation in Chicane. Based on this study, we then set tolerances on each item.
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MOPCH064 | The Specification, Design and Measurement of Magnets for the Energy Recovery Linac Prototype (ERLP) at Daresbury Laboratory | dipole, ERLP, linac, FEL | 175 | ||||
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The Energy Recovery Linac Prototype (ERLP) is currently under construction at Daresbury Laboratory in the UK and will serve as a test bed for the investigation of technologies and beam physics issues necessary for the development of Daresbury Laboratory's Fourth Generation Light Source (4GLS) proposal. A number of new ERLP beam transport system magnets have been procured for the project. The magnets have been designed, manufactured and measured by Danfysik following a stringent magnetic field specification produced by Daresbury Laboratory. In this paper we summarise the magnet specification. We then present details of the magnetic and mechanical design of the magnets and finally discuss the measurement techniques used to demonstrate that the field quality of the magnets satisfied the specification.
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MOPCH083 | Design Study for an Antiproton Polarizer Ring (APR) | antiproton, APR, target, polarization | 223 | ||||
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In the framework of the FAIR* project, the PAX collaboration has suggested a new experiments using polarized antiprotons**, in particular the study of the transverse spin structure of the proton. To polarize antiprotons the spin filtering method is proposed. The PAX collaboration is going to design the Antiproton Polarizer Ring (APR). In this contribution the design of this storage ring is described. The basic parameters of the APR are antiproton beam energy of 250 MeV and emittance in both planes of 250 pi mm mrad. The APR consists of two 180 degree arcs and two straight sections. One straight section houses the injection/extraction and the polarized internal target cell, in the other straight section, the electron cooler and a Siberian snake are located. Different optical conditions have to be fulfilled in the straight sections: (1) The target cell requires a beta function of less than 0.3 m. (2) The beam has to be circular and upright in the phase space ellipse at the target, the electron cooler, and the snake. (3) The antiproton beam should have a size of 10 mm for an emittance of 250 pi mm mrad. (4) The momentum dispersion has to be zero in both straight sections.
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*Conceptual Design Report for an International Accelerator Facility for Research with Ions and Antiprotons, available from www.gsi.de/GSI-Future/cdr.**PAX Technical Proposal, available from www.fz-juelich.de/IKP/pax. |
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MOPCH089 | Basic Aspects of the SIS100 Correction System Design | dipole, resonance, lattice, sextupole | 240 | ||||
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The basic concept and the main design features of the superconducting SIS100 correction system are presented. The system comprises 84 steerer magnets consisting of two orthogonal dipole windings each for correction of the beam close orbit in vertical and horizontal planes, 48 normal sextupole windings connected in two families with opposite polarities for chromaticity correction and 12 units containing skew quadrupoles, normal and skew sextupoles and octupoles as well. The correction system should operate in a pulse mode corresponding to the accelerator cycle, i.e., up to 1 Hz. The main magnetic, geometrical and electrical parameters of the corrector magnets were specified. They are based on the beam dynamic analysis within the frames of the DF-type SIS100 lattice at different betatron tune numbers and tolerable alignment and manufacturing errors of the main lattice dipole and quadrupole magnets. The problem of reasonable unification of the corrector modules is discussed also, including their geometrical sizes, maximum supply current and cooling at 4.5 K. The concept of the SIS100 corrector magnets is based on the pulsed correctors designed for the Nuclotron.
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MOPCH096 | LEIR Lattice | injection, electron, optics, lattice | 261 | ||||
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The Low Energy Ion Ring (LEIR) is a low energy ion cooling and accumulation ring and serves to compress long ion pulses from Linac 3 into high density bunches suitable for LHC ion operation. Issues of the LEIR lattice are to fulfil all constraints with a small number of quadrupoles and compensations of perturbations due to an electron cooler and gradients seen by the beam in the bending magnets during the ramp. Furthermore, experimental investigations via orbit reponse measurements will be reported.
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MOPCH102 | A Straight Section Design in RHIC to Allow Heavy Ion Electron Cooling | electron, interaction-region, RHIC, dipole | 279 | ||||
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The Relativistic Heavy Ion Collider (RHIC) has been continuously producing exciting results. One of the major luminosity limitations of the present collider is the intra beam scattering. A path towards the higher luminosities requires cooling of the heavy ion beams. Two projects in parallel electron and stochastic cooling are progressing very well. To allow interaction between electrons and the RHIC beams it is necessary to redesign one of the existing interaction regions in RHIC to allow for the longer straight section with fixed and large values of the betatron functions. We present a new design of the interaction region for the electron cooling in RHIC.
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MOPCH105 | A New RF Tuning Method for the End Regions of the IPHI 4-vane RFQ | rfq, simulation, dipole, proton | 285 | ||||
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The 3-MeV High Intensity Proton Injector (IPHI) RFQ is constituted by the assembly of three 2-m-long segments. The tuning of the end regions of such an accelerator with respect to the quadrupole mode is generally made by machining the thickness of the end plates. The dipole modes are moved away from the accelerator mode frequency by adding dipole rods and adjusting their length. In the case of the last IPHI RFQ segment, the tuning range given by possible plate thickness was not sufficient to adjust the frequency at 352 Mhz without modifying the notch depth, leading to serious engineering problems for the cooling, new thermo-mechanical simulations and drawings. To avoid these difficulties, a new way has been investigated by replacing the end plate thickness adjustment by a "quadrupole rod" length adjustment. These rods are situated between the beam axis and the dipole rods, and the tuning range is largely increased. The paper will describe this method applied to the IPHI RFQ and some experimental results obtained on the cold model.
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MOPCH107 | Tuning Procedure of the 6 Meter IPHI RFQ | rfq, dipole, coupling, LEFT | 291 | ||||
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In the framework of the IPHI project (High Intensity Proton Injector), the RFQ cavity is divided into 6 sections of 1 meter each, and assembled in 3 segments separated by coupling plates. We will present the tuning procedure of the aluminium RFQ cold model to set the accelerating mode frequency, a flat voltage profile and to minimize the dipole components of the accelerating voltage. This tuning procedure can be divided in three steps. First, dipole mode frequencies are adjusted with rods for the 3 separated segments. Second, RFQ end cells and coupling cells are tuned by mechanical machining of tuning plates. Third, using a fully automated bead-pull for the measurement of the field distribution inside every RFQ quadrants, the RFQ is tuned with 96 plungers in a small number of iterations. Tuning this 6-meter long cold model is a comprehensive training in view of the future tuning of the copper RFQ with the variable voltage profile.
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MOPCH108 | Error Study of LINAC 4 | linac, simulation, emittance, CERN | 294 | ||||
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Within the framework of the Joint Research Activity HIPPI (High Intensity Pulsed Proton Injector) of the CARE program, the conception study of the LINAC 4 accelerator which aims to intensify the proton flux available for the CERN injection line is pursued. The linac, operating in pulsed mode at 352 MHz, is designed to accelerate a 65 mA beam of H- ions up to an energy of 160 MeV. The requirements on acceptable beam emittance growth and particle loss are extremely tight. In order to determine the Drift Tube Linac tolerances, we examined the sensitivity of the LINAC 4 DTL to errors on the accelerating field and the focusing quadrupoles. Simulations were performed with the transport code TRACEWIN (CEA-Saclay, France). We will present results on individual sensitivities to a single error as well as the global impact of alignment and RF errors on the beam quality. Similarly, accelerating structures following the DTL in the LINAC4 design (CCDTL, SCL) have been studied.
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MOPCH111 | A Fast Beam Chopper for the RAL Front End Test Stand | emittance, linac, CERN, proton | 300 | ||||
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The FETS project at RAL will test a fast beam chopper, designed to address the requirements of high power proton drivers for next generation pulsed spallation sources and neutrino factories. A description is given of the novel RAL 'Fast - Slow' chopping scheme, and of candidate optical designs for the 3.0 MeV, 60 mA, H- Medium Energy Beam Transport (MEBT) line.
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MOPCH113 | Re-bunching RF Cavities and Hybrid Quadrupoles for the RAL Front-end Test Stand (FETS) | impedance, linac, proton, CCL | 306 | ||||
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The proposed FETS project at RAL will test a fast beam chopper in a 3.0 MeV H- Medium Energy Beam Transport (MEBT) line. Space restrictions in the MEBT line place constraints on component length and drive the requirement to identify compact component configurations. A description is given of candidate re-bunching RF cavities and hybrid quadrupole designs. The cavity options considered are the space efficient Drift Tube Linac type cavity (DTL) with integrated quadrupoles, and the high shunt impedance Coupled Cavity Linac type cavity (CCL) with external quadrupoles. The advantages and disadvantages of both structures are discussed and a comprehensive comparison between the two is made enabling the best cavity geometry choice. The compact hybrid quadrupole configurations considered are the 'tandem' combination of permanent magnet (PMQ) and electro-magnetic (EMQ) types, and the concentric combination of PMQ and laminar conductor (Lambertson) EMQ types.
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MOPCH116 | Electromagnetic Design of a Radio Frequency Quadrupole for the Front End Test Stand at RAL | simulation, rfq, dipole, ion | 315 | ||||
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The goal of the RAL front end test stand is to demonstrate cleanly chopped bunches of a 60mA H- ion beam at 3MeV. The acceleration of the H- ions from 65keV to 3MeV will be done using a radio frequency quadrupole (RFQ) operating at a resonant frequency of 324MHz. The two types of RFQ considered were a 4-vane and a 4-rod. The 4-vane has a higher Q-value but the post-production adjustment is limited. The 4-rod design is easier to manufacture but requires complicated cooling at 324MHz. The results of electromagnetic simulations using CST Microwave Studio are presented for the 4-vane type and 4-rod type RFQ.
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MOPCH130 | Simulations for SNS Ring Commissioning | target, RTBT, injection, extraction | 348 | ||||
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In preparation for SNS ring commissioning, a number of operational issues have been studied using ORBIT Code simulations. These include beam injection without the use of time-dependent painting, beam accumulation and transport to the extraction dump and to the target, optimal painting schemes for various beam intensities, detailed tracking through the extraction septum with fully correct geometry, quadrupole current constraints in the ring-to-target transfer line (RTBT), and detailed modeling of H minus carbon foil stripping at injection. All these studies incorporated detailed physics including beam-foil interactions, symplectic single particle tracking, space charge and impedances, and losses due to apertures and collimation.
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MOPCH163 | Analysis of Wakefields in the ILC Crab Cavity | dipole, luminosity, TESLA, simulation | 442 | ||||
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The large crossing angle schemes of the ILC need a correction of bunch orientation at the IP in order to recover a luminosity loss of up to 80%. The orientation of bunches can be changed using a transverse deflecting cavity. The location of the crab cavity would be close to the final focus, and small deflections caused by wakefields in the cavities could cause misalignments of the bunches at the IP. Wakefields in the FNAL CKM cavities have been analysed and their effects studied in view of use as the ILC crab cavity. Numerical simulations have been performed to analyse the transverse wakepotentials of up to quadrupole order modes in this cavity and the effect upon bunches passing through this cavity. Trapped modes within the CKM cavity have been investigated. Perturbation tests of normal conducting models of this cavity have been launched to verify these results. The effect of the final focus quadrupole magnets on the deflection given to the bunch have also been calculated and used to calculate luminosity loss due to wakefields.
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MOPCH191 | Copper Heat Exchanger for the External Auxiliary Bus-bars Routing Line in the LHC Insertion Regions | LHC, CERN, cryogenics, insertion | 508 | ||||
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The corrector magnets and the main quadrupoles of the LHC dispersion suppressors are powered by a special superconducting line (called auxiliary bus-bars line N), external to the cold mass and housed in a 50 mm diameter stainless steel tube fixed to the cold mass. As the line is periodically connected to the cold mass, the same gaseous and liquid helium is used for cooling the magnets and the line. The final sub-cooling process (from 4.5 K down to 1.9 K) consists of the phase transformation from liquid to superfluid helium. It is slightly delayed with respect to the magnets. To accelerate the process, a special heat exchanger has been designed. Located in the middle of the dispersion suppressor portion of the line it consists in creating a local sink of heat extraction, providing two additional λ fronts that propagate in opposite directions towards the line extremities. Both the numerical model and the sub-cooling analysis are presented in the paper for different configurations of the line. Design, manufacturing and integration aspects of the heat exchanger are described. Finally, the results of the qualification tests and the expected performance of the line are given.
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MOPLS011 | Investigations of the Parameter Space for the LHC Luminosity Upgrade | luminosity, LHC, insertion, separation-scheme | 556 | ||||
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Increasing the LHC luminosity by a factor of ten is a major challenge, not so much for the beam optics but certainly for the beam-beam long-range interactions and even more for the technology and layout: the quadrupole gradient, its physical aperture and tolerance to the energy deposition shall be significantly increased; its distance to the crossing point shall be reduced if the particle detectors can allow it. To help identifying consistent solutions in this multi-dimensional constrained space, a algorithmic model of an LHC insertion was prepared, based on the present LHC layout, i.e., "quadrupole first" and small crossing angle. The model deals with the layout, the beam optics, the beam-beam effect, the superconductor field margins and the peak heat deposition in the coils. The approach is simplified to allow a large gain in the design/computation time for optimization. First results have shown the need to use the Nb3Sn technology (or a material of equivalent performance) to reach the performance goal. In this paper, the model is refined to take into account the quench levels and temperature margins. The optimal insertions within the framework of this approach are identified.
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MOPLS017 | A Low Gradient Triplet Quadrupole Layout Compatible with NbTi Magnet Technology and Betastar=0.25m | LHC, sextupole, luminosity, CERN | 574 | ||||
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The paper presents a triplet layout option with long (ca. 100 m total triplet length), low gradient (45 T/m to 70 T/m) quadrupole magnets. Assuming a maximum magnet diameter of 200mm, the peak coil field at the magnet coils still remains below 7 T which is still compatible with conventional NbTi magnet technology. The peak beta function inside the triplet magnets reaches 18 km and the configuration therefore requires an additional chromaticity correction scheme similar to a dipole first layout option. However, at the same time, the presented solution provides an interesting alternative to a high gradient triplet layout which requires the new Nb3Ti magnet technology.
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MOPLS037 | Beams Injection System for e+e- Collider VEPP-2000 | injection, collider, optics, luminosity | 622 | ||||
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Electron-positron collider VEPP-2000 is under commissioning at the Budker Institute of Nuclear Physics. The paper presents the injection system of the collider delivering the beam from the booster storage ring BEP with maximum energy 900 MeV. A matching of the beam injection with the storage ring optics is done with respect to a nonlinear kicker field. Features of beam diagnostic and transfer line magnets including pulse septums (100 mksec; 30 kGs) and fast kickers (20 nsec; 70 kV) are described. Results of the magnetic measurements and their comparison to calculated data are given.
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MOPLS040 | Magnet Structure of the VEPP-2000 Electron-positron Collider | sextupole, collider, dipole, focusing | 628 | ||||
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Electron-positron collider VEPP-2000 with beam energy up to 1 GeV is under commissioning at Budker Institute. This paper presents magnetic elements of the storage ring including 13T focusing superconducting solenoids in interaction regions. Features of magnet elements design and magnetic measurements results are given together with comparison to previously calculated data.
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MOPLS044 | Luminosity Variations along Bunch Trains in PEP-II | luminosity, electron, synchrotron, positron | 640 | ||||
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In spring of 2005 after a long shut-down, the luminosity of the B-Factory PEP-II decreased along the bunch trains by about 25-30%. There were many reasons studied which could have caused this performance degradation, like a bigger phase transient due to an additional RF station in the Low-Energy-Ring (LER), bad initial vacuum, electron cloud, chromaticity, steering, dispersion in cavities, beam optics, etc. The initial specific luminosity of 4.2 sloped down to 3.2 and even 2.8 for a long train (typical: 130 of 144), later in the run with higher currents and shorter trains (65 of 72) the numbers were more like 3.2 down to 2.6. Finally after steering the interaction region for an unrelated reason (overheated BPM buttons) and the consequential lower luminosity for two weeks, the luminosity slope problem was mysteriously gone. Several parameters got changed and there is still some discussion about which one finally fixed the problem. Among others, likely candidates are: the LER betatron function in x at the interaction point got reduced, making the LER x stronger, dispersion reduction in the cavities, and finding and fixing a partially shorted magnet.
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MOPLS060 | Design of an Interaction Region with Head-on Collisions for the ILC | extraction, optics, dipole, luminosity | 682 | ||||
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An interaction region with head-on collisions is considered an alternative to the baseline configuration of the International Linear Collider, including two interaction regions with finite crossing-angles (2 and 20 mrad). Although more challenging from the point of view of the beam extraction, the head-on scheme is favoured by the experiments because it allows a more convenient detector configuration, particularly in the forward region. The optics of the head-on extraction is revisited by separating the e+ and e- beams horizontally, first by electrostatic separators operated at their LEP nominal field and then using a defocusing quadrupole of the final focus beam line. In this way the septum magnet is protected from the beamstrahlung power. Newly optimized final focus and extraction optics are presented, including a first look at post-collision diagnostics. The influence of parasitic collisions is shown to lead to a region of stable collision parameters. Beam and beamstrahlung photon losses are calculated along the extraction elements. Issues concerning the design of the large bore superconducting final focus magnets, common to both incoming and outgoing beams, are considered.
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MOPLS061 | Optimization of the e-e- Option for the ILC | luminosity, extraction, simulation, optics | 685 | ||||
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The e-e- running mode is one of the interesting physics options for the International Linear Collider. The luminosity for e-e- collisions is reduced by mutual defocusing due to the strong electromagnetic fields that the bunches experience during collisions. The resulting beamstrahlung energy loss and beam-beam deflection angles as function of the vertical transverse offset are different compared to the e+e- collisions. In this paper, the dependence of these observables with the offset for different beam sizes has been analysed to optimize performances for the e-e- mode, taking into account the requirements of the beam-beam deflection based intra-train feedback system. A first study of the implications for the final focus and extraction line optics is also presented for the cases of the 2mrad and 20mrad ILC base line crossing angle geometries.
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MOPLS063 | Accelerator Component Vibration Studies and Tools | TESLA, resonance, DESY, vacuum | 688 | ||||
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This talk will cover a research program on accelerator component vibrations. Ground motion and technical noise, such as vacuum and refrigeration systems, couple to the beam, mainly via quadrupoles, making the design of their supports, especially, in the case of the superconducting magnets, critical. This program includes investigation of cold mass vibration of the superconducting quadrupoles inside an accelerating module and sensor performance in the main or fringe field of a linear collider detector. Seismometer accuracy limitations in correlated ground motion measurements are also being investigated.
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MOPLS075 | Progress towards Crab Cavity Solutions for the ILC | luminosity, focusing, electron, positron | 724 | ||||
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In order to achieve acceptable luminosity for ILC crossing angles greater than a few mrad, RF deflection cavities must be used to rotate electron and position bunches leading up to the IP. A bunch that passes through a deflection cavity at a phase where the deflection averages to zero receives a crab kick leading to a finite rotation at the IP. For a beam energy of 500GeV and a crossing angle of 20mrad, the required crab kick is about 19.5MV at 1.3GHz and 6.5MV at 3.9GHz. Cavities are needed on both beams and are likely to be positioned about 12m before the IP. Any RF phase error between the bunch and the cavity leads to a deflection of the bunch in addition to a rotation of the bunch. Any differential phase error between the cavities leads to differing deflections and consequential loss in luminosity. Collaborative work with FNAL, being undertaken to develop a variant of their 3.9GHz CKM cavity optimised for an ILC solution, is described. Current analysis favours a solution with four nine-cell cavities on each beam. It is anticipated that the cavities will be run CW and driven from small Klystron/s (< 5kW) or solid state amplifiers.*
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*We would like to thank Chris Adolphsen, SLAC, for his help in technical discussions, which were greatly appreciated. |
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MOPLS077 | The 2mrad Crossing Angle Interaction Region and Extraction Line | extraction, optics, beam-transport, interaction-region | 730 | ||||
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A complete optics design for the 2mrad crossing angle interaction region and extraction line was presented at Snowmass 2005. Since this time, the design task force has been working on developing and improving the performance of the extraction line. The work has focused on optimising the final doublet parameters and on reducing the power losses resulting from the disrupted beam transport. In this paper, the most recent status of the 2mrad layout and the corresponding performance are presented.
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MOPLS078 | Benchmarking of Tracking Codes (BDSIM/DIMAD) using the ILC Extraction Lines | extraction, beam-transport, optics, SLAC | 733 | ||||
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The study of beam transport is of central importance to the design and performance assessment of modern particle accelerators. In this work, we benchmark two contemporary codes - DIMAD and BDSIM, the latter being a relatively new tracking code and built within the framework of GEANT4. We consider both the 20mrad and 2mrad extraction lines of the International Linear Collider and perform disrupted beam tracking studies of heavily disrupted post-collision electron beams. We find that the two codes in most cases give an equivalent description of the beam transport.
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MOPLS094 | Luminosity Tuning at the Interaction Point | sextupole, luminosity, simulation, linac | 774 | ||||
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Minimisation of the emittance in a linear collider is not enough to achieve optimal performance. For optimisation of the luminosity, tuning of collision parameters such as angle, offset, waist, etc. is needed, and a fast and reliable tuning signal is required. In this paper tuning knobs are presented, and their optimisation using beamstrahlung as a tuning signal is studied.
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MOPLS096 | Effects of Wake Fields in the CLIC BDS | CLIC, luminosity, emittance, betatron | 780 | ||||
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The wake fields due to collimators in the Beam Delivery System of CLIC are modeled using a conventional approach. According to the chosen ranges of parameters, differences in the transverse kicks due to both the geometric and resistive wall components for different regimes are highlighted (inductive or diffractive for the geometric wake fields, short- or long-range, ac or dc for the resistive wall wake fields). A module for particle tracking along the BDS including the effect of wake fields has been introduced in PLACET, and the first tracking results are shown.
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MOPLS097 | Progress on the CTF3 Test Beam Line | CLIC, CTF3, lattice, extraction | 783 | ||||
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In CLIC, the RF power to accelerate the main beam is produced by decelerating a drive beam. The test beamline (TBL) of the CLIC test facility (CTF3) is designed to study and validate the stability of the drive beam during deceleration. This is one of the R&D items required from the International Linear Collider Technical Review Committee to demonstrate feasibility of CLIC. It will produce 30 GHz rf power in the GW range and allow to benchmark computer codes used for the CLIC decelerator design. Different options of this experimental beam line are discussed.
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MOPLS098 | Study of an ILC Main Linac that Follows the Earth Curvature | emittance, linac, alignment, laser | 786 | ||||
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In the base line configuration, the tunnel of the ILC will follow the earth curvature. The emittance growth in a curved main linac has been studied, including static and dynamic imperfections. These include effects due to current ripples in the power supplies of the steering coils, the impact of the beam position monitor scale errors.
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MOPLS099 | A Study of Failure Modes in the ILC Main Linac | linac, klystron, simulation, lattice | 789 | ||||
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Failures in the ILC can lead to beam loss or even damage the machine. Also failures that do not lead to beam loss can affect the luminosity performance, in particular since some time is required to recover from them. In the paper a number of different failures is being investigated and the impact on the machine performance is being studied.
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MOPLS100 | CLIC Final Focus Studies | CLIC, luminosity, octupole, sextupole | 792 | ||||
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The design of the CLIC final focus system is based on the local compensation scheme proposed by P. Raimondi and A. Seryi. However, there exist important chromatic aberrations that deteriorate the performance of the system. This paper studies the optimization of the final focus based on the computation of the high orders of these aberrations using MAD-X and PTC. The use of octupole doublets to reduce the size of the halo in the locations with aperture limitations is also discussed.
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MOPLS102 | Beam Dynamic Studies and Emittance Optimization in the CTF3 Linac at CERN | emittance, CTF3, linac, simulation | 798 | ||||
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Small transverse beam emittances and well-known lattice functions are crucial for the 30 GHz power production in the Power Extraction and Transfer Structure (PETS), and for the commissioning of the delay loop of the CLIC Test Facility 3 (CTF3). Following beam-dynamics-simulation results, two additional solenoids were installed in the CTF3 injector in order to improve the emittance. During the runs in 2005 and 2006, an intensive measurement campaign to determine Twiss parameters and beam sizes was launched. The results obtained by means of quadrupole scans for different modes of operation suggest rms emittances well below the nominal (100 pi mm mrad) and a convincing agreement with PARMELA simulations.
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MOPLS113 | Commissioning of the ALTO 50 MeV Electron Linac | linac, electron, target, ion | 825 | ||||
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The ALTO 50 MeV electron linac is dedicated to the production of neutron-rich radioactive nuclei using the photo-fission process and the optimisation of the target-ion source system for SPIRAL 2 and Eurisol projects. A description of the accelerator consisting in 3 Mev injector (old test station of LAL), LIL accelerating structure, RF power plant, beam line, control system and diagnostics will be given. Specified and measured beam parameters will be compared to show the performance for the photo-fission and eventually other applications.
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MOPLS117 | Tuning Algorithms for the ILC Beam Delivery System | sextupole, luminosity, coupling, emittance | 837 | ||||
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Emittance preservation is an important aspect in the design and running of the International Linear Collider (ILC) with a direct consequence on the luminosity of the machine. The Beam Delivery System represents a major problem in this respect as it produces emittance dilution effects that are difficult to correct and that have a direct effect on the emittance as seen at the interaction point, and thus upon the luminosity of the machine. Tuning algorithms for this section of the machine rely on the correction of aberrations through the use of linear and higher order knobs, using corrections magnets distributed throughout the system. Alternative systems are also discussed. The design and implementation of these tuning algorithms, and their effectiveness in a variety of cases, are investigated and estimates made for tolerances on a variety of error sources. Simulations results are also presented for models of the ATF-2 accelerator under development at KEK, with comparisons made to the ILC design.
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MOPLS130 | Implications of a Curved Tunnel for the Main Linac of CLIC | linac, emittance, laser, CLIC | 864 | ||||
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Preliminary studies of a linac that follows the earth's curvature are presented for the CLIC main linac. The curvature of the tunnel is modeled in a realistic way by use of geometry changing elements. The emittance preservation is studied for a perfect machine as well as taking into account imperfections. Results for a curved linac are compared with those for a laser-straight machine.
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MOPLS135 | Correction of Vertical Dispersion and Betatron Coupling for the CLIC Damping Ring | emittance, sextupole, dipole, coupling | 873 | ||||
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The sensitivity of the CLIC damping ring to various kinds of alignment errors have been studied. Without any correction, fairly small vertical misalignments of the quadrupoles and, in particular, the sextupoles, introduce unacceptable distortions of the closed orbit as well as intolerable spurious vertical dispersion and coupling due to the strong focusing optics of the damping ring. A sophisticated beam-based correction scheme has been developed to bring the design target emittances and the dynamic aperture back to the ideal value. The correction using dipolar correctors and several skew quadrupole correctors allows a minimization of the closed-orbit distortion, the cross-talk between vertical and horizontal closed orbits, the residual vertical dispersion and the betatron coupling.
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MOPLS140 | Tuning Algorithms for the ILC Damping Rings | emittance, damping, coupling, dipole | 888 | ||||
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Emittance preservation is an important aspect in the design and running of the International Linear Collider with a direct consequence on the luminosity of the machine. One major area of concern is in the damping rings, where the extracted emittances set the effective lower limits for the rest of the machine. Algorithms for tuning this system have been investigated, and simulations have been performed to understand the design and implementation issues. The different algorithms have been applied to the various damping ring designs, and the effectiveness of each algorithm has been assessed. A preliminary recommendation of tuning algorithm, and its effectiveness under various conditions, is given.
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MOPLS143 | Suppression of Secondary Emission in a Magnetic Field using Sawtooth Surface | electron, dipole, damping, impedance | 897 | ||||
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The effect of surface roughness on the secondary electron emission from a sawtooth surface in a magnetic field under electron bombardment is investigated using a Monte-Carlo method. Some of the secondary electrons emitted from the sawtooth surface return to the surface within their first few gyrations, resulting in low effective secondary electron yield. A sawtooth surface in magnetic field can significantly reduce the secondary emission yield below the multipacting threshold.
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TUZAPA01 | Present Status of the J-PARC Accelerator | linac, injection, acceleration, proton | 930 | ||||
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The Japan Proton Accelerator Research Complex (J-PARC) is a joint project of High Energy Accelerator Research Organization (KEK) and Japan Atomic Energy Agency (JAEA), which started on April 1, 2001. The J-PARC accelerator complex is composed of a 400 MeV proton linac, a 3 GeV Rapid-Cycling Synchrotron (RCS), and a 50 GeV Proton Synchrotron (MR). A 180-MeV beam ( in the first stage) accelerated by the linac is to be injected into the RCS, and further accelerated there to 3 GeV. The RCS will operate at 25 Hz, and will provide the Materials and Life Science Facility (MLF) with a 1-MW beam (600 kW during 180 MeV injection). There are two extraction sections in the MR: fast extraction for neutrino experiment and slow extraction for the Hadron Facility. A linac beam with a peak current of 30 mA and an energy of 19.7 MeV was successfully accelerated in Sep. 2004 using the first tank of the Drift Tube Linac in KEK. Now three accelerators are under installation. The beam commissioning of the linac will start in this December and those of the RCS and the MR will start in Sep. 2007 and May 2008, respectively. Status of installation and plan for commissioning run will be presented.
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Transparencies
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TUPCH009 | Beam Measurements and Manipulation of the Electron Beam in the BESSY-II Transferline for Topping Up Studies | emittance, synchrotron, booster, injection | 1010 | ||||
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The BESSY-II storage ring based synchrotron radiation source will be upgraded to allow for continuous topping up operation. In order to achieve a high injection efficiency between the booster synchrotron and the storage ring, the transferline will be equipped with novel beam size monitors and collimators. This paper describes the collimator design and first beam measurements of the transverse emittance. The transverse emittance is measured using the quadrupole scan technique. The data taking and the analysis procedure is given together with results and comparision with simulations.
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TUPCH039 | A Phase Space Tomography Diagnostic for Pitz | space-charge, diagnostics, PITZ, gun | 1091 | ||||
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The Photo Injector Test Facility at DESY in Zeuthen (PITZ) is a European collaboration developing RF photocathode electron guns for light source and linear collider projects. As part of the collaborative work being partially funded by the EU's FP6 programme, CCLRC Daresbury Laboratory and DESY are designing and building a phase space tomography diagnostic based on a set of multiple quadrupoles and view screens. In order to measure the beam emittance, four screens with intermediate quadrupole doublets will be used. The equipment will be installed and tested at PITZ as part of the facility upgrade presently ongoing. Following simulations of the gun using the ASTRA code at a range of energies, simulations of the electron beam parameters through the matching and tomography sections must be undertaken in order to specify the optimum arrangement of magnets and screens.
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TUPCH048 | A Study of Emittance Measurement at the ILC | emittance, laser, electron, coupling | 1115 | ||||
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The measurement of the ILC emittance in the ILC beam delivery system and the linac is simulated. Estimates of statistical and machine-related errors are discussed and implications for related diagnostics R&D are inferred.
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TUPCH060 | Beam Collimator System in the J-PARC 3-50BT Line | emittance, LEFT, synchrotron, injection | 1148 | ||||
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For the J-PARC 50 GeV Main Ring Synchrotron (MR), the design beam emittance is 54 pi mm mrad. On the other hand, the 3 GeV beam from the Rapid Cycling Booster Synchrotron (RCS) may have a large halo component upto 216 pi mm mrad. In order to absorb the halo component, a beam collimator system will be installed in the beam transport line called as the 3-50BT, which connects the RCS and the MR. From the view of the hands-on maintenance, high endurance structure is adopted. The beam collimator design including the beam optics is reported in this paper.
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TUPCH061 | Installation of Beam Monitor Sensors in the LINAC Section of J-PARC | linac, KEK, vacuum, pick-up | 1151 | ||||
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In the LINAC section of J-PARC, we have several type of sensors of monitor, i.e, Beam Position Monitor, Beam Profile Monitor, Beam Size Monitor, Current Monitor, Beam Phase Monitor, Beam Loss Monitor. Those sensors are being installed currently. The procedures, remarks during the installation, status are described in this paper. As an examle, the beam postion monitors are one of sensors which are taken cared intensively for their positioning on their housing quadrupole magnet, then our cares during their installation are described .
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TUPCH064 | Beam-based Alignment Strategy for the Group Controlled Magnets System | alignment, simulation, proton, controls | 1160 | ||||
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The beam based alignment of the beam position monitor (BPM) becomes an important tool to reduce the closed orbit distortion (COD) in the recent accelerator. Normally, it requires the independent control of the quadrupole field. Changing the current of a quadrupole magnet, one would find the unperturbed position. However, the J-PARC Rapid-Cycling Synchrotron (RCS) has seven quadrupole families and only group of each family can be controlled simultaneously. There is neither separate power supplies nor auxiliary coil windings on each individual magnet. A similar alignment procedure is applicable for the coupled-controlled magnet system, but it becomes very complicated. For the simplest case, three magnets grouped together, four different beam orbits have to be measured at three different BPM locations. The method and some simulation results for J-PARC/RCS case will be presented in this report.
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TUPCH115 | Status of the 70 MeV, 70 mA CH Proton-DTL for FAIR | GSI, proton, impedance, antiproton | 1283 | ||||
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The CH-type cavity shows promising features in the low and medium beta range: its high accelerator gradient and the high level of shunt impedance together with the compact transverse dimensions make this new cavity a good candidate for proton acceleration up to 100 MeV. That's why GSI has decided to base the new high current proton injector for the new FAIR facility on that structure: the operating frequency will be 352 MHz with an injection energy of 3 MeV. In order to improve the technical experience on this new kind of structure, IAP has built a model consisting of 8 equidistant gaps for a total cavity-length of 60 cm. Several design options with respect to welding, alignement, cooling and RF joints were studied and compared each other. A new concept for the end-cells geometry will result in the desired flatness of the electric field along the cavity axis and, at the same time, allow effective integration of internal quadruple lenses. Finally, the electric quadruple content of CH-structure gaps is listed in dependence on the geometry of the cell.
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TUPCH123 | Dipole Stabilizing Rods System for a Four-vane RFQ: Modeling and Measurement on the TRASCO RFQ Aluminum Model at LNL | rfq, dipole, coupling, simulation | 1301 | ||||
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The Dipole Stabilizing Rods (DSR's) are devices used in order to reduce a priori the effect of perturbation on the operating mode of a four-vane RFQ caused by neighboring dipole modes by increasing the frequency spacing between the TE210 mode and dipole modes, without, in principle, affecting the quadrupole TE210 mode. They have proven to be particularly useful in the case of coupled RFQ's whose overall length is significantly greater than the operating wavelength. In this article we present a circuit model of such DSR's, that, used in combination with a transmission line model of a four vane RFQ, has allowed us to predict the dimensioning of the DSR's in the case of the aluminum model of TRASCO RFQ. The DSR parameters and, in general, the accuracy of the model have been also confirmed by HFSS simulations and by RF measurements on the above-mentioned model.
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TUPCH135 | Characteristics of the PEFP 3 MeV RFQ | rfq, dipole, electron, coupling | 1334 | ||||
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A four-vane type 3 MeV, 350 MHz RFQ (Radiofrequency Quadrupole) has been developed as a front end part of PEFP (Proton Engineering Frontier Project) 100 MeV accelerator. After the completion of field tuning and high power conditioning at reduced duty, the initial operation of the RFQ with beam was carried out. During the initial test period, several parameters related with the RF and beam were measured to characterize the performance of the RFQ. Based on these measurements, several suggestions for further system improvement were proposed. In this paper, the initial test results are discussed and the suggestions for the system improvement are summarized.
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TUPCH174 | Vacuum Issues and Challenges of SIS18 Upgrade at GSI | dipole, ion, vacuum, GSI | 1426 | ||||
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For the present experiment programm and for the planned FAIR facility the heavy ion synchroton SIS18 at GSI has to reach the space charge limit for highly and intermediate charged heavy ions. For the booster mode of SIS18 the number of 1x1012 ions per second in 4 Hz operation mode is specified. To achive this requirement a dynamic vacuum in the 10-12 mbar region has to be garanteed. The poster will present the status of recent R & D work concerning the SIS18 vacuum upgrade, with a focus on the new GSI NEG coating facility and on ion-induced desorption measurements using advanced ion beam analysis.
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TUPCH175 | The Vacuum System of FAIR Accelerator Facility | vacuum, cryogenics, ion, cathode | 1429 | ||||
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The FAIR accelerator complex consists of two superconducting synchrotrons (SIS100 and SIS300) with a circumference of 1083.6m each, a high energy beam transport system (HEBT) with a total length of about 2.5km and four storage rings (CR, RESR, HESR and NESR). Their length varies between 200m and 550m. For each of the subsystems, different vacuum requirements have to be fulfilled. The vacuum system of SIS100 and SIS300 consists of cryogenic and bakeable room temperature sections, where a pressure in the lower 10-12 mbar range is needed. For HEBT, also a combination of cryogenic and room temperature sections, a vacuum pressure of 10-9 mbar is sufficient. The storage rings will be operated in a pressure range from 10-9 mbar to 10-12 mbar. In the poster a detailed layout of the vacuum systems and technical solutions will be presented.
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TUPLS003 | A Perfect Electrode to Suppress Secondary Electrons inside the Magnets | electron, dipole, positron, KEKB | 1489 | ||||
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Electron cloud due to multipacting in the positron ring of B-factories is one of the limitations on the machine performance. Electron cloud in the drift region can be suppressed by solenoid. However, solenoid doesn't work inside a magnet. Numerical studies show that there is strong multipacting in the dipole magnet of the B-factory positron ring. Electrons also can be trapped inside quadrupole and sextupole magnets. The electron cloud from the dipole magnet and wiggler in the positron damping ring of the ILC is a critical limitation on the choice of damping ring circumference, which directly results in a choice of two 6km rings as the baseline for the positron damping ring. Various electrodes have been studied using the program CLOUDLAND. Our studies show that a wire type of electrode with a few hundred voltages works perfectly to kill the secondary electrons inside various magnets.
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TUPLS006 | Optics of a 1.5 TeV Injector for the LHC | LHC, dipole, optics, injection | 1496 | ||||
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A concept is being developed to install a second ring above the LHC to accelerate protons from 450 GeV to 1.5 TeV prior to injection into the LHC. The arc and dispersion suppressor optics of the LHC would be replicated in the injector using combined function 'transmission line' magnets orginally proposed for the VLHC. To avoid costly civil construction, in the straight sections housing detectors at least, the injector and LHC must share beampipes and some magnets through the detector portion of the straights. Creating the appropriate optics for these injector-LHC transition regions is very challenging: In addition to matching to the nominal LHC lattice functions at these locations, the changes in altitude of 1.1 m between the injector and LHC must be accomplished achromatically to avoid emittance blowup when the beams are transferred to the LHC.
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TUPLS008 | A new HOM Water Cooled Absorber for the PEP-II B-factory Low Energy Ring | dipole, scattering, coupling, impedance | 1499 | ||||
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At high currents and small bunch lengths beam line components in the PEP-II B-factory experience RF induced heating from higher order RF modes (HOMs) produced by scattered intense beam fields. A design for a passive HOM water cooled absorber for the PEP-II low energy ring is presented. This device is to be situated near HOM producing beamline components such as collimators and provide HOM damping for dipole and quadrupole modes while minimizing impedance to the beam. We present a method of optimizing the impedance characteristics of such devices through the evaluation of loss factors and absorber effectiveness for specific modes using scattering parameter and wakefield analysis.
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TUPLS029 | Optical Scheme of an Electrostatic Storage Ring | storage-ring, lattice, simulation, ion | 1553 | ||||
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We consider the optical scheme of an electrostatic storage ring for low energy heavy ions/molecules* with special requirements to type of optical functions. Results of calculation are presented.
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*C. P. Welsch et al. Proc. of PAC03, 12-16 May 2003, Portland, Oregon, USA, p.1622. |
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TUPLS038 | The MAFF IH-RFQ Test Stand at the IAP Frankfurt | rfq, ion, ion-source, emittance | 1577 | ||||
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The IH-type RFQ for the MAFF project at the LMU in Munich is presently under construction and will be integrated into a beam test stand at the IAP in Frankfurt. It is the second RFQ following the IH resonator concept and the first one that can be directly compared to a very similar 4-rod type machine, namely the REX-ISOLDE RFQ at CERN. The MAFF RFQ has been designed to accelerate rare isotope beams (RIBs) with mass to charge ratios up to 6.3 from 3 keV/u to 300 keV/u at an operating frequency of 101.28 MHz with an electrode voltage of 60 kV. First RF-measurements have already been executed and can be compared to appropriate simulation results. Parts of the test stand are currently under construction, such as the volume ion source for He+ at an extraction voltage of 12 keV and an electrostatic quadruplet for injection with an integrated steering system. These tests and accompanying theoretical investigations will be done with special respect to the applicability of such normal conducting RFQ accelerators to the EURISOL post accelerator.
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TUPLS044 | The 3D Beam Dynamics with the Space Charge in the Low and Middle Energy Super-conducting Option of HIPPI | focusing, emittance, simulation, proton | 1594 | ||||
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For the low and middle energy of the High Intensity Proton Pulse Injector (HIPPI), a superconducting option is considered.The 3D beam dynamics simulation results in the slot and the finger-slot sections covering the energy range from 3 to 160 MeV are presented. The optimization aim is the increase of beam current together with the reduction of emittance growth, beam losses and costs. The slot structure is compared with the conventional spoke structure.
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TUPLS052 | Beam Dynamics of the PEFP Linac | rfq, proton, emittance, linac | 1612 | ||||
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The PEFP Linac consists of a 50 keV ion source, LEBT, 3 MeV RFQ, 20 MeV DTL called DTL1, MEBT, and 100 MeV DTL called DTL2. The MEBT includes two small DTL tanks, which match the 20 MeV proton beams into the DTL2, and a bending magnet, which extracts the 20 MeV proton beams to the experimental hall. We will present the full beam dynamics study from the entrance of the DTL1 to the end of DTL2 with the initial beam parameters obtained from a simulation study of the RFQ. Our study focuses on the longitudinal beam matching in order to compensate the missing RF effect between every neighboring DTL tanks as well as the full beam matching between DTL1 and DTL2.
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TUPLS053 | Beam Dynamics of a High Current IH-DTL Structure for the TWAC Injector | rfq, ion, emittance, synchrotron | 1615 | ||||
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A powerful ion injector based on a laser ion source is needed for an efficient operation of the Tera Watt Accumulator (TWAC) complex including a heavy ion synchrotron and a storage ring, which is under progress now at ITEP, Moscow. The Interdigital H-type drift tube linac (IH-DTL) structure operating at 162 MHz is proposed for the second stage of the injector linac behind of a 81 MHz RFQ. Consisting of independently driven sections with inter-tank quadrupole triplet focusing, this structure will accelerate highly stripped ions with charge-to-mass ratios above 1/3 in the energy range from 1.57 MeV/u at the RFQ exit to 7 MeV/u. Beam currents up to 100 mA are expected for medium ions like Carbon or Aluminum. Since the rf frequency is duplicated at the entrance of the IH-DTL in order to reduce size as well as power consumption, space charge effects are dominant at full current. Beam dynamics and structure parameters are discussed in detail.
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TUPLS054 | The Isochronous Mode of the Collector Ring | emittance, ion, closed-orbit, octupole | 1618 | ||||
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The isochronous mode of a storage ring is a special ion-optical setting in which the revolution time of circulating ions of one species does not depend on their velocity spread. In this mode the ring can be used for mass measurement of exotic nuclei. The Collector Ring (CR) [1] of the FAIR project [2] will operate in such mode as time-of-flight spectrometer for short-lived exotic nuclei (T1/2 > 20 μs) produced and selected in flight with the Super-FRS fragment separator [3]. This technique has been developed at the ESR [4]. The dependence of the revolution time in the isochronous ring from its transverse acceptance, the closed orbit distortion, and nonlinear imperfection of the magnet field was investigated analytically and with a Monte-Carlo simulation. The corresponding results will be presented.
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References: [1] A. Dolinskii et. al., GSI Annual Report, 2004 [2] W. Henning, Nucl. Phys. A721 (2003)211c [3] H. Geissel, et. al., Nucl. Instr. Meth. B204 (2003)71 [4] M. Hausmann et. al., Nucl. Instr. Meth. A 446 (2000)569 |
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TUPLS055 | First Section of a 352 MHz Prototype Alvarez DTL Tank for the CERN SPL | linac, CERN, proton, laser | 1621 | ||||
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In the Linac4/SPL projects at CERN, 352 MHz 30 mA DTL Alvarez accelerating structure will be used to accelerate protons between 3 and 40 MeV. The R&D for the development of a prototype structure for the energy range from 3 to 10 MeV is taking place jointly at ITEP and VNIIEF. The design of this 2.7 m Alvarez tank containing 27 drift tubes is described in this document. Results of calculations of the section parameters are presented. One of the main features of the design is the use of permanent magnets made of SmCo5 alloy as quadrupole focusing lenses (PMQ) inside the drift tubes. Details of the experimental PMQ-equipped drift tube are described.
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TUPLS070 | Chromaticity Control in Linear-field Nonscaling FFAGs by Sextapoles | focusing, lattice, betatron, LEFT | 1657 | ||||
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Because of their high repetition rate and large apertures, FFAGs are proposed for high-current medical accelerators suitable for cancer therapy. The linear-field nonscaling FFAG is made from repeating cells containing D and F combined function magnets. The betatron tune profiles decrease with momentum; this leads to the crossing of resonances. We examine how sextapole magnets may be used to flatten the tune profile; in particular (i) whether it is better to place them at the D or F; (ii) what strength is required; and (iii) what is their effect on the closed orbits and path length? The orbit geometry is derived from a thin-element model and the tunes from power series in the quadrupole strength. Chromaticity is corrected by coupling focusing strength to dispersion, which is far stronger in the F element. The zeros of the orbit dispersion become the poles of the "sextapole strength to flatten the tune at some particular momentum". We demonstrate that a weak F sextapole can produce a substantial horizontal tune flattening, and has little impact on other optical properties. Contrarily, placing the sextapole at the D element may destroy the dynamic aperture and or vertical focusing.
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TUPLS071 | Minimum Cost Lattices for Nonscaling FFAGs | lattice, LEFT, closed-orbit, acceleration | 1660 | ||||
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Previously, linear-field FFAG lattices for muon acceleration have been optimized under the condition of minimum path length variation. For non-relativistic particles, as are employed in the hadron therapy of cancer, that constraint is removed allowing a wider range of design choices. We adopt the thin-element kick model for a degenerate F0D0 cell composed of D and F combined function magnets. The dipole field components are parametrised in terms of the bending at the reference momentum and the reverse bend angle. The split between positive and negative bending sets the shape of the closed orbits. The cost function, based on stored magnetic energy, is explored in terms of the split. Two cost minima are found, one corresponding to minimum peak magnet field in the F element, and another to minimum radial aperture in the D element. Analytic formulae are given for the minimization conditions. The minimum field lattice is similar to existing designs based on minimizing the path length variation, but the minimum aperture lattice presents a new direction for future detailed design studies.
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TUPLS081 | Flat Beams and Application to the Mass Separation of Radioactive Beams | emittance, ion, dipole, heavy-ion | 1687 | ||||
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The notion of flat beam is now well established and has been proven theoretically and experimentally with applications for linear colliders. In this paper, we propose a new and simple demonstration of the "flat beam theorem", and a possible application in the frame of radioactive ion beams (RIB) production. It consists in using a magnetized multi-specie heavy ion beam extracted from a high frequency ECR source, decoupling the transverse phase planes in such a way to obtain a very small emittance in the horizontal one, and using a dipole to separate the isotopes. A design of such a transport and separation line will be proposed and commented.
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TUPLS109 | Present Status of the L3BT for J-PARC | injection, emittance, simulation, linac | 1756 | ||||
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L3BT is a beam transport line from J-PARC (Japan Proton Accelerator Research Complex) linac to the succeeding 3-GeV RCS (Rapid Cycling Synchrotron). The construction of the L3BT has been almost finished. The beam commissioning of the L3BT will be started soon. On the other hand we have performed 3D particle simulations with PARMILA and IMPACT to evaluate the performance of the halo scraping, momentum compaction and beam diagnostics. In this paper, results of the beam simulation of the L3BT are presented. The construction status of the L3BT is also presented in brief.
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TUPLS119 | Design Study of the Axial Injection System of C400 Cyclotron | ion, cyclotron, injection, ion-source | 1786 | ||||
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Computer modeling results on the axial injection system design are given. Results of simulations of the Carbon, Hydrogen and Helium ion beam injection are presented.
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TUPLS134 | Managing the Quality Assurance Documentation of Accelerator Components Using an EDMS | DESY, XFEL, TTF, PETRA | 1819 | ||||
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Quality assurance (QA) documents are often collected locally on a per-component basis by the manufacturing teams, while project engineers require global evaluations of the QA documents e.g. for production control or during installation and commissioning of the machine. DESY is using an Engineering Data Management System (EDMS) for supporting and unifying the QA documentation of different accelerator components. The EDMS provides dedicated user interfaces which are optimized for the needs of the specific engineering teams which are working on the components (including industrial manufacturers), and at the same time integrates the QA documents into a central database for further overall analysis and applications. The poster introduces the general structure of QA procedures, describes the benefits of using an EDMS for QA documentation and describes examples from different applications at XFEL and PETRA III.
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WEYPA01 | Beam Delivery System in ILC | linac, electron, feedback, luminosity | 1852 | ||||
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The presentation will review the challenges of this key ILC sub-system in terms of beam performances, machine protection system, collimation, interaction with the detector and compare them with the achievements in SLC and FFTB. It will then present the world-wide organization to define and make the necessary R&D for the design, beam simulations and benchmarking in tests facilities, especially the ATF2 facility under construction at KEK. It will explore the major issues both from the beam dynamics and the technological point of view, as well as the plans foreseen and the schedule to address them. It will finally analyze the possible upgrade in energy together with the possible limitations and associated issues.
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Transparencies
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WEOBPA01 | First Results of the CRFQ Proof of Principle | rfq, proton, radio-frequency, impedance | 1873 | ||||
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The Circular Radiofrequency Quadrupole is a new concept of a storage and accelerator ring for intense beams of light and heavy ions, protons and electrons. It is basically a Linear Radiofrequency Quadrupole completely bent on a circle. The advantages, which are expected to be the same performance features of a linear RFQ, would be smaller overall dimension with respect to accelerators with comparable beam intensity and emittance*. A collaboration between BNL and Italian research institute and universities was set up at the end of 2002 with the aim of the proof of the bending principle**. The prototype design is based on a 4-rods scheme and have a linear sector followed by a 45-degree curved sector. The 1mA proton beam, produced by a reconditioned RF source, go through a beam gap diameter of 10mm with circular 10mm diameters rods. Each sector is 700mm long and is placed in a 150mm diameter pipe***. The RF power at 202.56MHz is fed by a CERN "Frank James" 50kW amplifier. In this paper the first power and beam tests of the linear sector are presented.
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*A.G. Ruggiero, C-A/AP/65 note, Brookhaven National Laboratory, October 2001. **A.G. Ruggiero et al., Proceedings of the EPAC 2004 conference.***D. Davino et al., Proceedings of the EPAC 2004 conference. |
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Transparencies
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WEPCH006 | Comparison between Simulations and Measurements of Low Charge Electron Bunch in the ELSA Facility | simulation, laser, electron, ELSA | 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.
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WEPCH010 | Beam-based Alignment for the Storage Ring Multipoles of Synchrotron SOLEIL | alignment, sextupole, SOLEIL, multipole | 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.
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WEPCH011 | Optimisation of a New Lattice for the ESRF Storage Ring | optics, resonance, lattice, ESRF | 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.
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WEPCH012 | Comparison of Betatron Function Measurement Methods and Consideration of Hysteresis Effects | betatron, optics, storage-ring, injection | 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.
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WEPCH015 | Measurement and Correction of Dispersion in the VUV-FEL | undulator, simulation, DESY, electron | 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.
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WEPCH016 | Spurious Vertical Dispersion Correction for PETRA III | emittance, wiggler, damping, closed-orbit | 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.
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WEPCH017 | Front-to-end Simulation of the Injector Linac for the Heidelberg Ion Beam Therapy Centre | simulation, ion, linac, rfq | 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.
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WEPCH018 | Finite Elements Calculations of the Lattice and Ring Acceptance of the Heidelberg CSR | CSR, lattice, ion, storage-ring | 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.
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WEPCH022 | Study of the Effect of Multipolar Components in the SPARC Emittance Compensation Gun Solenoid | emittance, multipole, gun, cathode | 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.
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WEPCH028 | Position Shuffling of the J-PARC Main Ring Magnets | sextupole, resonance, lattice, betatron | 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.
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WEPCH029 | Injection and Extraction Orbit of the J-PARC Main Ring | extraction, injection, beam-losses, kicker | 1987 | ||||
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The J-PARC main ring (MR) accelerates a high intensity proton beam and deliver to the neutrino experimental hall by the fast extraction and to the hadron experimental facility by the slow extraction. The beam from the rapid cycle synchrotron (RCS) is injected by the bunch to bucket transfer into the MR. The MR has two beam dump lines, the first one is used to dump the beam at injection energy and the second one can be used to abort accelerated beam. The beam loss at the injection and extraction is one of the critical issue for high intensity proton accelerators. We report designed injection and extraction orbits and discuss about the beam apertures and the beam loss.
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WEPCH030 | Beam Dynamics of a 175MHz RFQ for an IFMIF Project | rfq, coupling, emittance, linac | 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.
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WEPCH043 | On the Implementation of Experimental Solenoids in MAD-X and their Effect on Coupling in the LHC | LHC, coupling, optics, injection | 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.
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WEPCH044 | Interaction Region with Slim Quadrupoles | LHC, luminosity, interaction-region, beam-beam-effects | 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.
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WEPCH045 | Sorting Strategies for the Arc Quadrupoles of the LHC | LHC, optics, resonance, simulation | 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.
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WEPCH046 | Design and Validation with Measurements of the LEIR Injection Line | optics, ion, dipole, linac | 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.
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WEPCH047 | Procedures and Accuracy Estimates for Beta-beat Correction in the LHC | LHC, simulation, coupling, power-supply | 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.
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WEPCH049 | Closed Orbit Correction of TPS Storage Ring | closed-orbit, dipole, synchrotron, emittance | 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.
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WEPCH050 | Correction of Vertical Dispersion and Betatron Coupling for the TPS Storage Ring | emittance, coupling, sextupole, betatron | 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.
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WEPCH051 | Isochronous Magneto-optical Structure of the Recirculator SALO | injection, dipole, recirculation, site | 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.
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WEPCH052 | Injection System for Kharkov X-ray Source NESTOR | injection, alignment, storage-ring, lattice | 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.
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WEPCH055 | A New Algorithm for the Correction of the Linear Coupling at TEVATRON | coupling, optics, kicker, controls | 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.
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WEPCH058 | Progress with Collision Optics of the Fermilab Tevatron Collider | optics, luminosity, resonance, lattice | 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.
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WEPCH059 | Linear Lattice Modeling of the Recycler Ring at Fermilab | lattice, storage-ring, coupling, controls | 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.
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WEPCH060 | Linear and Nonlinear Coupling Using Decoupling Transformations | coupling, storage-ring, lattice, sextupole | 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.
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WEPCH062 | Precision Measurement and Improvement of Optics for e+, e- Storage Rings | optics, coupling, lattice, betatron | 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.
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WEPCH063 | Measurements and Modeling of Eddy Current Effects in BNL's AGS Booster | vacuum, booster, dipole, AGS | 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.
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WEPCH064 | Fast Compensation of Global Linear Coupling in RHIC using AC Dipoles | coupling, RHIC, resonance, injection | 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.
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WEPCH068 | 6-D Beam Dynamics Studies in EMMA FFAG | LEFT, acceleration, dipole, electron | 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**.
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*http://www.hep.ph.ic.ac.uk/iss/**http://hepunx.rl.ac.uk/uknf/wp1/emodel/ |
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WEPCH088 | High Order Aberration Correction | controls, simulation, multipole, background | 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.
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WEPCH092 | Dynamical Aperture Studies for the CERN LHC: Comparison between Statistical Assignment of Magnetic Field Errors and Actual Measured Field Errors | LHC, simulation, optics, dipole | 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.
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WEPCH112 | Database Extension for the Beam Dynamics Simulation Tool V-code | simulation, gun, electron, multipole | 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.
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WEPCH116 | Recent Simulation Results of the Polarized Electron Injector (SPIN) of the S-DALINAC | simulation, electron, gun, MAMI | 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.
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WEPCH124 | BDSIM - Beamline Simulation Toolkit Based on Geant4 | simulation, electron, CLIC, scattering | 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.
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WEPCH139 | WISE: An Adaptative Simulation of the LHC Optics | LHC, simulation, CERN, power-supply | 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.
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WEPCH149 | PBO LAB (tm) Tools for Comparing MARYLIE/MAD Lie Maps and TRANSPORT/TURTLE Transfer Matrices | optics, beam-transport, controls, simulation | 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.
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WEPCH150 | The Accelerator Markup Language and the Universal Accelerator Parser | lattice, multipole, collider, CERN | 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.
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WEPCH165 | A Nonlinear Transport Line for the Optimization of F18 Production by the TOP Linac Injector | target, octupole, linac, proton | 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.
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WEPCH168 | Development toward Turn-key Beam Delivery for Therapeutic Operation at HIMAC | extraction, ion, heavy-ion, emittance | 2325 | ||||
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Since 1994, more than 2500 cancer patients have been treated by carbon ion beam at HIMAC. To increase the number of patients per day, we have studied the reproducibility of the beam quality, such as the position, profile and intensity, during the operation. For this purpose, the accelerator needs high reproducibility to minimize the beam tuning time with more flexible scheme. Further, the irradiation system and the accelerator need to ensure dose uniformity. As a result of this study, it was found that a slight change of the magnetic field in the transport line would not affect the beam quality. However, a slight change of the horizontal tune strongly affects the beam quality because of a resonant slow-extraction. In this paper, we report about our investigation and present result of the development.
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WEPCH180 | A Dramatically Reduced Size in the Gantry design for the Proton-Carbon Therapy | betatron, hadron, focusing, dipole | 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.
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WEPCH189 | Design of the 20 MeV User Facilities of Proton Engineering Frontier Project | proton, optics, survey, controls | 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.
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WEPLS003 | Simulation of MICE Using G4MICE | simulation, emittance, factory, coupling | 2400 | ||||
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In the Muon Ionisation Cooling Experiment (MICE), muons will be fired one by one through one or two cooling cells. The experiment will be used to optimise simulation of an ionisation cooling channel for a future Neutrino Factory. This is achieved by measuring the position of each muon in six-dimensional phase space and examining the behaviour of muons collected into bunches offline. The experiment will be run with a number of different input beams, magnet configurations, RF configurations and absorber types. We present the simulated detector and cooling performance of the MICE cooling channel using the G4MICE simulation code for a range of configurations. We detail the simulation of engineering, field and detector models and examine the implications for the cooling efficacy and measurement.
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WEPLS016 | Studies of a Gas-filled Helical Muon Beam Cooling Channel | simulation, emittance, dipole, sextupole | 2424 | ||||
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A helical cooling channel (HCC) can quickly reduce the six dimensional phase space of muon beams for muon colliders, neutrino factories, and intense muon sources. The HCC is composed of solenoidal, helical dipole, and helical quadrupole magnetic fields to provide the focusing and dispersion needed for emittance exchange as the beam follows an equilibrium helical orbit through a continuous homogeneous absorber. We consider liquid helium and liquid hydrogen absorbers in HCC segments that alternate with RF accelerating sections and we also consider gaseous hydrogen absorber in pressurized RF cavities imbedded in HCC segments. In the case of liquid absorber, the possibility of using superconducting RF in low magnetic field regions between the HCC segments may provide a cost effective solution to the high repetition rate needed for an intense neutrino factory or high average luminosity muon collider. In the gaseous hydrogen absorber case, the pressurized RF cavities can be operated at low temperature to improve their efficiency for higher repetition rates. Numerical simulations are used to optimize and compare the liquid and gaseous HCC techniques.
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WEPLS054 | Higher-order Effect Compensation in Magnetic Compressor for < 50 fs Electron Bunch Generation | electron, linac, gun, simulation | 2502 | ||||
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An ultrashort electron bunch is essential for pulse radiolysis, which is a pump-probe measurement based on an ultrashort electron beam and an ultrashort light. In Osaka University, a laser photocathode electron linear accelerator with a magnetic compressor has been constructed for the femtosecond electron bunch generation. An electron beam with bunch length of 98 fs was successfully generated and used in pulse radiolysis. However, an electron beam with bunch length of < 50 fs is required for development of pulse radiolysis with time resolution of 100 fs. To generate such a short bunch, higher order disadvantage effects, which are caused by the fringing fields of the magnets in the compressor, should be compensated. In this paper, a compensation technique of higher-order effects was proposed by using a nonlinear energy modulation in the bunch produced in the linear accelerator by re-phasing the linac away from the zero-crossing of the rf (i.e., away from the linear slope). In the simulation, we compressed the electron bunch into 48 fs at bunch charge of 0.1 nC.
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WEPLS064 | Wiggler for ILC Cooler | wiggler, emittance, focusing, dipole | 2526 | ||||
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We represented the concept of a wiggler with linear piecewise field dependence. This eliminates nonlinearities in wiggler. This type of wiggler can be recommended for usage in ILC cooler.
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WEPLS065 | The Effect of Vaccum Vessel Permeability on the Field Quality within Dipole and Quadrupole Magnets at the Energy Recovery Linac Prototype (ERLP) at Daresbury Laboratory | dipole, vacuum, ERLP, linac | 2529 | ||||
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The Energy Recovery Linac Prototype (ERLP) is currently under construction at Daresbury Laboratory in the UK and will serve as a test bed for the investigation of technologies and beam physics issues necessary for the development of Daresbury Laboratory's Fourth Generation Light Source (4GLS) proposal. To assist with the material specification of the vacuum vessels, analyses have been done on the effect of vessel permeability on the magnetic field quality within quadrupole and dipole magnets. It is found that for dipoles where the specified maximum relative dipole field variation over the good field region is ± 1x 10-4 or for quadrupoles where the specified maximum relative gradient variation is ±1 1x10-3, the transverse size of the good field region decays unacceptably for relative permeability > 1.006. However, for the dipoles where the specified maximum relative dipole field variation is ± 1x10-3, the decay of the good field region is more gradual and would safely permit a material with relative permeability >1.006 to be used for the vacuum vessel within these dipoles.
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WEPLS066 | Harmonic Measurement and Adjustment of Diamond Quadrupoles | sextupole, DIAMOND, octupole, alignment | 2532 | ||||
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The 254 quadrupole magnets for Diamond, manufactured by Tesla Engineering Ltd, were measured for harmonic content to a level around 1 part in 104. In order to meet the demanding requirements on field quality, procedures were then developed to adjust the relative positions of the magnet quadrants such that the desired harmonic levels were achieved. This process was integrated into the analysis software so that the needed changes were specified. The measurements were performed on a seven-coil rotating coil rig, which also enabled the alignment of the magnet in five spatial degrees of freedom to the specified accuracy. In this report we describe the measurement and correction procedures and present a summary of the results that were obtained.
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WEPLS067 | Magnets for the 3 GeV Booster Synchrotron for the Diamond Light Source | dipole, sextupole, booster, DIAMOND | 2535 | ||||
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The Diamond Booster is a full energy injector for the Diamond Storage Ring. It is designed to accelerate electrons from 100 MeV to 3 GeV at a 5 Hz repetition rate. The lattice is a missing dipole FODO lattice consisting of 22 unit cells with 36 dipoles, 44 quadrupoles, 28 sextupoles and 44 correctors, distributed around a circumference of 158.4 m. The dipole field will be ramped from 0.026 T at injection to 0.809 T at 3 GeV; the quadrupoles will have a maximum operating gradient of 15T/m. The initial design of pole tip profiles was carried at Diamond, with the magnets then manufactured by DANFYSIK A/S as part of preassembled girder units (44 in total), complete with vacuum vessels. High quality was required to meet the accelerator physics requirements of alignment, positioning accuracies and field tolerances over the required good field apertures. Materials, ramp rates and field range have been selected to obtain almost linear response during magnet ramping. This paper describes the main features of the magnetic designs and measurement results; the magnets have now been delivered and installed at Diamond.
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WEPLS070 | The Elettra Booster Magnets Construction Status | sextupole, booster, dipole, ELETTRA | 2541 | ||||
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The third generation light source ELETTRA has been in operation since 1993. A new 2.5 GeV full energy booster injector has been approved and founded last year. It will replace the existing linear injector limited to a maximum energy of 1.2 GeV. During last year, after having completed the specifications and the preliminary magnetic and mechanical design, the orders for all the magnets were assigned to two European firms. The paper reports on the magnets' construction status and the requested specifications.
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WEPLS072 | Results of Field Measurements for J-PARC Main Ring Magnets | sextupole, multipole, optics, injection | 2547 | ||||
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The mass production of J-PARC main ring magnets had been completed till the end of fiscal year 2004. Those magnets consists of 97 bending magnets with 6-m in length, 216 quadrupole magnets with 11 families and 72 sextupole magnets. We have been measured the magnetic field for all of these magnets and we will finish it in March, 2006. The obtained distributions for the BL products of bending magnets and the GL products of quadrupole magnets are within the required tolerance limits, values of which are estimated by the beam optics for COD correction, etc. The measured multi-pole components for these magnets, and so on, will be also reported.
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WEPLS073 | A Super Strong Adjustable Permanent Magnet Quadrupole for the Final Focus in a Linear Collider | permanent-magnet, linear-collider, collider, CERN | 2550 | ||||
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An adjustable permanent magnet quadrupole has been fabricated to demonstrate its feasibility for use in the final focus of a linear collider. The supposed requirements for such a final focus lens are the tight stabilities of its integrated field gradient and magnetic center, plus it must have adjustable strength. The high temperature coefficient of the permanent magnet material NEOMAX is compensated by use of the MS-1 Fe-Ni alloy. The magnet has two concentric rings of NEOMAX. The replacement of the inner ring with a smaller diameter one is planned in order to reach the highest gradient with the current configuration of the quadrupole system; the system has to be scaled down in size to fit in a real linear collider final focus system. A precise magnetic field measurement system is also under fabrication that will be able to measure the magnetic center to a fraction of a micron.
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WEPLS074 | SESAME Magnets System | dipole, sextupole, focusing, storage-ring | 2553 | ||||
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In this paper the SESAME storage ring magnet system is described. The storage ring consists of 16 bending magnets with a maximum field of 1.455 T and vertical gradient of 2.79 T/m, 32 focusing quadrupoles with a maximum gradient of 16.92 T/m, 32 defocusing quadrupoles with a maximum gradient of 10.23 T/m, 32 focusing sextupoles with a maximum differential gradient of 200 T/m2 and 32 defocusing sextupoles with the maximum differential gradient of 300 T/m2. The horizontal/vertical correctors will be embedded inside focusing/defocusing sextupoles. For the quadrupole and sextupole, a design similar to ANKA has been adopted. The magnetic and electrical design of dipoles and correctors, field profile and higher order multipoles optimization will be presented.
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WEPLS080 | Magnets for the Storage Ring ALBA | sextupole, multipole, dipole, storage-ring | 2562 | ||||
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The Storage Ring ALBA is a 3.0 GeV synchrotron light source under construction in Barcelona (Spain). The Storage Ring, has a circumference of 268.8 m and comprises 32 combined magnets, 112 quadrupoles, and 120 sextupoles. This paper will describe the design and the present state of these magnets. The combined magnet has a central field of 1.42 T and a large gradient of 5.65 T/m, since most of the vertical focusing happens at these combined magnets. The 112 quadrupoles have been designed for a maximum gradient of 22 T/m. The bore diameter will be 61 mm and the lengths range from 200 to 500 mm. Each quadrupole will be individually powered. The 120 sextupoles are divided in 9 families. There are two lengths of sextupoles 150 and 220 mm and the maximum sextupole gradient is 600 T/m2. The bore diameter is 76 mm. The sextupole magnets will also be equipped with additional coils for vertical steering, horizontal steering and quadrupolar skew correction.
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WEPLS084 | AC Field Measurements of Fermilab Booster Correctors Using a Rotating Coil System | booster, dipole, sextupole, synchrotron | 2574 | ||||
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The first prototype of a new corrector package for the Fermilab Booster Synchrotron is presently in production. This water-cooled package includes normal and skew dipole, quadrupole and sextupole magnets to control orbit, tune and chromaticity of the beam over the full range of Booster energies (400 MeV-8 GeV). These correctors must make rapid excursions from the 15 Hz excitation cycle of the main synchrotron magnets, in some cases even switching polarity in approximately 1 ms at transition crossing. To measure the dynamic changes in the field during operation, a new method based on a relatively slow rotating coil system is proposed. The method pieces together the measured flux from successive current cycles to reconstruct the field harmonics. This paper describes the method and presents initial field quality measurements from the corrector prototype.
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WEPLS087 | Status of the Development of the FAIR Superconducting Magnets | dipole, superconducting-magnet, GSI, ion | 2577 | ||||
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For the planned 'Facility for Antiprotons and Ion Research' (FAIR), a variety of superconducting magnets is foreseen. The synchrotrons SIS 100 and SIS 300 will use fast-pulsed superferric and superconducting cos (theta) magnets. The storage ring CR and the SuperFRS will be equipped with large-scale superferric magnets, while in the storage ring HESR RHIC-type magnets are foreseen. The status of the R&D activities will be presented.
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WEPLS090 | Full Length Superferric Dipole and Quadrupole Prototype Magnets for the SIS100 at GSI: Status of the Design and Manufacturing | dipole, GSI, synchrotron, ion | 2583 | ||||
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The SIS100, one of the two basic accelerators of the future Facility for Antiproton and Ion Research FAIR at GSI, should provide acceleration of U28+ and proton beams for 0.5 s with a pulse repetition rate of 1 Hz. In the accelerator magnetic system superferric 2 T dipoles of about 3 m length and 35 T/m quadrupoles of about 1 m length will be used. The magnet coils are made from hollow NbTi composite cable cooled with two-phase helium flow at 4.5 K. The maximum operating current of 7500 A is supposed. The lattice comprises 108 dipoles and 168 quadrupoles. The elliptic beam pipe inner sizes have been fixed to 130x60 mm2 for the dipole and 135x65 mm2 for the quadrupole The design approach is based on the improved versions of the Nuclotron fast-cycling magnets that provide significant less AC loss at 4.5 K, better quality of the magnetic field and a higher long-term mechanical stability of the magnet coils. The AC losses in the magnets for the strongest SIS100 operating cycle at 4.5 K are expected to be about 13 W/m and 17 W/m in the full length prototype dipole and quadrupole magnets respectively.
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WEPLS091 | Analysis of the Superferric Quadrupole Magnet Design for the SIS100 Accelerator of the FAIR Project | GSI, dipole, synchrotron, ion | 2586 | ||||
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The heavy ion fast-cycling synchrotron SIS100 is the "workhorse", of the future Facility for Antiproton and Ion Research FAIR at GSI in Darmstadt. The main lattice parameters of the accelerator are defined now so the main engineering problems of the new superferric magnets should be analyzed and solved too. We present the results of finite element calculations and compare them with the experimental data from investigation of the model magnets to characterize the expected AC loss properties of the full length prototype quadrupole. We discuss the appropriate new coil structure aimed at minimizing the heat releases at 4.5 K, but providing the requested long-term mechanical stability against dynamic Lorentz forces and thermal cooling cycles as well.
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WEPLS093 | 3D Field Computation for the Main Prototype Magnets of the SIS100 Accelerator of the FAIR Project | dipole, multipole, magnet-design, GSI | 2592 | ||||
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Fast cycling superferric magnets are planned for use in the new international accelerator Facility for Antiprotons and Ion Research (FAIR) at GSI, Darmstadt. The dipoles and quadrupoles have to provide the required field quality from the injection field of 0.25T and 4.3T/m up to the maximum values of 2.1T and 35T/m respectively. The complex 3D magnetic field distribution due to the longitudinal component Bz near the yoke end regions and the presence of eddy currents also in the bulk construction elements as well as in a mechanical stable beam pipe design can create unacceptable static and dynamic nonlinearities. The detailed knowledge of these effects is necessary to control the field quality for all operating cycles to be provided by the SIS100 accelerator. We discuss the methodical problems of 3D finite element calculations (ANSYS) of the local and the integral nonlinearities, considering also the problems caused by the various nonlinear and anisotropic material properties and by the structure elements of the yoke and beam pipe. The calculated integral static and the affected by eddy currents harmonic coefficients are presented.
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WEPLS094 | 3D Magnetic Field and Eddy Current Loss Calculations for Iron Dominated Accelerator Magnets using ANSYS Compared with Results of Noncommercial Codes | GSI, simulation, dipole, synchrotron | 2595 | ||||
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The design of fast ramped superferric magnets with repetition rates in the order of 1Hz requires reliable software tools to calculate the complex 3D magnetic field quality as well as the impact of eddy current and hysteresis loss. Various technological construction details should be taken into account to obtain a high field quality. We present a methodical study of these questions based on ANSYS calculations for simplified dipole models. The details of these analysis are compared with recently published results obtained by different special codes, i.e. an integral and the FIT method. The time dependences of eddy current power due to longitudinal magnetic field component at the yoke ends, the transient field distribution in the yoke volume and the total eddy current loss are investigated, choosing the identical geometry with the same magnetic and electric properties of the lamination steel used by the other codes. The conclusions for the application potential of the different methods are discussed.
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WEPLS096 | Design and Calculation of a Superferric Combined Magnet for XFEL | dipole, XFEL, DESY, background | 2598 | ||||
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A planned European X-ray Free Electron Laser so-called XFEL is being developed within the framework of an international collaboration. The design and fabrication of a prototype of a combined magnet is part of the Spanish contribution to this project. This magnet consists of a superferric quadrupole for focusing and two dipoles (horizontal and vertical) for steering, glued around the beam tube. The magnet will be operated in a superfluid helium bath. The aperture is 78 mm. The quadrupole gradient is 35 T/m whereas each dipole field is about 0.04 T. The magnetic saturation is limited to 5% at nominal current, which is quite a challenging specification for such aperture and gradient. As the overall length of the helium vessel is just 300 mm, the calculation of the magnetic field is a pure 3-D problem which has been solved and optimized using two different FEM codes to cross-check the results. This paper also gives some guidelines about the fabrication techniques most suitable for the first prototype, which is now under construction.
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WEPLS098 | Experience with the Quality Assurance of the Superconducting Electrical Circuits of the LHC Machine | LHC, dipole, pick-up, octupole | 2604 | ||||
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The coherence between the powering reference database and the Electrical Quality Assurance (ELQA) is guaranteed on the procedural level. However, a challenge remains the coherence between the database, the magnet test and assembly procedures, and the connection of all superconducting circuits of the LHC. In this paper, the methods, tooling, and procedures for the ELQA during the assembly phase of the LHC will be presented in view of the practical experience gained in the LHC tunnel. The parameters measured at ambient temperature such as the dielectric insulation and the impedance transfer function of assembled circuits will be discussed. Some examples of detected polarity errors and the treatment of non-conformities will be presented.
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WEPLS101 | First Computation of Parasitic Fields in LHC Dipole Magnet Interconnects | dipole, LHC, CERN, multipole | 2613 | ||||
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The Large Hadron Collider (LHC), now under construction at CERN, will rely on about 1600 main superconducting dipole and quadrupole magnets and over 7400 superconducting corrector magnets distributed around the eight sectors of the machine. Each type of magnets is powered by dedicated superconducting busbars running along each sector and passing through the iron yokes of the main dipole and quadruple magnets. In the numerous magnet interconnects, the busbars are not magnetically shielded from the beam pipes and produce parasitic fields that can affect beam optics. We review the 3D models which have been built with the ROXIE software package to evaluate these parasitic fields and we discuss the computation results and their potential impacts on machine performance.
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WEPLS102 | The Construction of the Superconducting Matching Quadrupoles for the LHC Insertions | LHC, insertion, CERN, alignment | 2616 | ||||
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After several years of intensive effort, the construction of the superconducting matching quadrupoles for the LHC insertions is nearing completion. We retrace the main events of the project from the initial development of quadrupole magnets of several types to the series production of over 100 complex cryo-magnets, and report on the techniques developed for steering of the production. The main performance parameters for the full series, such as quench training, field quality and magnet geometry are presented. The experience gained in the production of these special superconducting magnets is of considerable value for further development of the LHC insertions.
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WEPLS103 | The Field Description Model for the LHC Quadrupole Superconducting Magnets | LHC, CERN, controls, insertion | 2619 | ||||
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The LHC control system requires an accurate forecast of the magnetic field and the multipole field errors to reduce the burden on the beam-based feed-back. The Field Description for the LHC (FIDEL) is the core of this forecast system and is based on the identification and physical decomposition of the effects that contribute to the total field in the magnet apertures. The effects are quantified using the data obtained from series magnetic measurements at CERN and they are consequently modelled empirically or theoretically depending on the complexity of the physical phenomena. This paper presents a description of the methodology used to model the field of the LHC magnets particularly focusing on the results obtained for the LHC Quadrupoles (MQ, MQM and MQY).
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WEPLS105 | Performance of the LHC Arc Superconducting Quadrupoles towards the End of their Series Fabrication | CERN, LHC, factory, dipole | 2625 | ||||
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The fabrication of the 408 main arc quadrupole magnets and their cold masses will come to an end in summer 2006. A rich collection of measurement and test data has been accumulated and their analysis is presented in this paper. These data cover the fabrication and the efficiency in the use of the main components, the geometrical measurements and the achieved dimensional precision, the warm magnetic measurements in the factory and the performance at cold conditions, especially the training behaviour. The scrap rate of the NbTi/Cu conductor as well as that of other components turned out to be acceptably low and the quench performance measured was in general very good. Most quadrupoles measured so far exceeded the operating field gradient with one or no quench. The multipole content at cold was measured for a limited numbers of quadrupoles as far as needed for verifying the warm-to-cold correlation. From the point of view of field quality, all quadrupoles could be accepted for the machine and the measures taken to overcome the problem of a too high permeability of a batch of collars are discussed.
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WEPLS106 | Design, Performance and Series Production of Superconducting Trim Quadrupoles for the Large Hadron Collider | CERN, LHC, target, insertion | 2628 | ||||
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The Large Hadron Collider (LHC) will be equipped with several thousands of superconducting corrector magnets. Among the largest ones are the superconducting trim quadrupoles (MQTL). These twin-aperture magnets with a total mass of up to 1700 kg have a nominal gradient of 129 T/m at 1.9 K and a magnetic length of 1.3 m. Sixty MQTL are required for the LHC, 36 operating at 1.9 K in and 24 operating at 4.5 K. The paper describes the design features, and reports the measured quench performance and magnetic field quality of the production magnets. The MQTL magnet production is shared between CERN and industry. This sharing is simplified due to the modular construction, common to all twin-aperture correctors.
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WEPLS109 | Test Results of Fermilab-built Quadrupoles for the LHC Interaction Regions | LHC, alignment, interaction-region, target | 2637 | ||||
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The US-LHC Accelerator Project has recently completed the manufacturing and testing of the Q2 optical elements for the LHC interaction region final focus. Each Q2 element consists of two identical quadrupoles (MQXB) with a dipole orbit corrector (MQXB). The Fermilab designed MQXB has a 70 mm aperture and a peak operating gradient of 215 T/m. This paper summarizes the test results for the MQXB program with emphasis on quench performance and alignment studies.
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WEPLS112 | Study of 2-in-1 Large-aperture Nb3Sn IR Quadrupoles for the LHC Luminosity Upgrade | LHC, dynamic-aperture, magnet-design, luminosity | 2643 | ||||
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After LHC operates for several years at nominal parameters, it will be necessary to upgrade it to higher luminosity. Replacement of the low-beta insertions with higher performance design based on advanced superconducting magnets is one of the most straightforward steps in this direction. An interesting option for a new IR design is a double bore inner triplet with separation dipoles placed in front of the focusing quadrupoles. This approach reduces the number of parasitic collisions by more than a factor of three with respect to the quadrupoles-first option and allows independent field error correction for each beam. Several designs of the 2-in-1 Nb3Sn quadrupole magnets suitable for the LHC IR upgrade have been studied, including magnets with "cold" and "warm" iron yokes based on symmetric or asymmetric coils. This paper describes the design concepts of 2-in-1 large-aperture IR quadrupoles and compares their major performance parameters, including aperture, field gradient, field quality, electromagnetic stresses in the coils, and discuss some technological aspects of magnet fabrication.
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WEPLS124 | Diamond Booster Magnet Power Converters | booster, controls, dipole, DIAMOND | 2664 | ||||
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This paper will describe the design, factory tests, commissioning and early operation of the Diamond Booster Power Converters. The Power Converters covered are the Dipole, Quadrupole with two outputs, two bi-polar Sextupoles and 44 Steerers. The actual achieved performance will be compared with the specification and the extensive modelling that was carried out during the design phase. The design includes measures to enhance the reliability of the power converters, such as redundancy, plug-in modularity, component de-rating and component standardisation. All the Diamond power converters use the same digital controller, manufactured under licence from the Paul Scherrer Institute.
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WEPLS125 | Diamond Storage Ring Magnet Power Converters | controls, dipole, sextupole, power-supply | 2667 | ||||
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The DC Magnet Power Converter requirements for the Storage Ring of the Diamond Project are described together with performance, commissioning and initial operating experience. In addition to meeting the required performance, emphasis during the design phase was placed on reliability and minimising the mean time to repair a power converter. A modular design, built-in redundancy, EMC filtering and testing, component de-rating and standardisation have all been adopted. The power modules for the 200A supplies were subject to highly accelerated stress screening. All converters are switched mode with full digital control and a common control interface. Every power converter appears identical to the Controls Network, from the lowest power corrector up to the 800 kW Storage Ring Dipole Converter.
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WEPLS128 | The Italian Hadrontherapy Center (CNAO): A Review of the Power Supply System for Conventional Magnets | synchrotron, dipole, power-supply, controls | 2676 | ||||
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A hadron (Carbon/Proton) medical centre based on a synchrotron accelerator dedicated to the cure of deep tumours is under construction in Pavia (Italy) under the joint responsibility of CNAO (Centro Nazionale di Adroterapia Oncologica) and INFN (Istituto Nazionale di Fisica Nucleare). This paper describes the power supply system, made up of about 200 units designed by LNF, and whose converters for the synchrotron ring and related low, medium and high energy transfer lines are now under construction by the major Italian companies. The power supplies requirements and electrical characteristics will be reported describing the most interesting topologies that fulfill the requested performances together with the main features of each power supply topology. Synchrotron dipoles, quadrupoles, sextupoles and resonance sextupole power supplies have tight characteristics with respect to precision class (current resolution, residual ripple, short-long term stability, etc.) that range from 5 ppm to 500 ppm, fast dynamical response with bandwidth up to some hundreds hertz, high power from tens of kW to many MW and output current ranging from hundreds of A to 3 kA.
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WEPLS132 | New Magnet Power Supply for PAL Linac | linac, controls, power-supply, damping | 2685 | ||||
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Since the completion of PLS in 1994, PLS Linac magnet power supply(MPS) has been operated for 12 years with 12-bit resolution and 0.1% stability. Improvement in the resolution and the reliability of the Linac MPS is highly required now for the stable beam injection and 4th generation light source research. To improve MPS, we developed new compact MPS of 16-bit resolution and 20ppm stability using four-quadrant switching scheme with 50kHz MOSFET switching device. Bipolar MPS for corrector magnet consists of main power board, control power board, regulator board and CPU board. Size of each board is only 100mm width and 240mm depth. Unipolar MPS for quadrupoles and solenoid magnets is composed by parallel-operation of two main power boards, doubling the current output. Output of MPS is 10V, ±10A for the bipolar and 50V, 50A for the unipolar magnet. In this paper, we report on the development and characteristics of the new MPS for PAL linac.
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WEPLS141 | Operational Experience with the LHC Waveguide Mode Reflectometer | LHC, dipole, CERN, insertion | 2709 | ||||
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The LHC microwave mode reflectometer (assembly version) reached operational status by the end of 2005. It is now routinely used in the LHC tunnel to take data on the beam-screen of the individual LHC magnets and also groups of magnets with lengths up to 200 meter. The reflectometer operates in the frequency range from about 4GHz to 8 GHz and employs mode selective launchers. Data traces of typically 16000 data points are taken in the frequency domain with subsequent Fourier transformation into the time domain and numerical waveguide mode dispersion compensation. This paper discusses the operational aspects of the system as well as methods for clutter (fake reflection) elimination and procedures for cross-checks in case of a suspected obstacle or other fault.
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THPPA03 | The First CW Accelerator in USSR and a Birth of Accelerating Field Focussing | focusing, rfq, proton, ion | 2755 | ||||
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In the absence of Professor Teplyakov, Robert Jameson will present the work for which Professor Teplyakov is awarded the 2006 EPS-AG Prize for Achievement. The abstract of Professor Teplyakov's presentation follows: As CW linear accelerators became required, it appeared an absolute necessity to change the initial part of the accelerator. The initial part should prepare bunches of charged particles for the further acceleration in the main part. The CW accelerator should also be economic and reliable. The problem was solved using the principles of adiabatic capture of particles and low energy injection with focusing by means of the RF field. The acceleration of bunches with non-increasing charge density was the basic idea. It allowed reduction of the injection energy without reducing the current. By 1972, initial testing in IHEP Protvino was accomplished, and the first accelerated beam was obtained in an RFQ. The URAL-30 proton linac was commissioned in 1977 in IHEP. It applies RFQ-focusing from injection up to the top energy of 30 MeV. From 1985 until the present, this facility routinely operates as an injector to a booster proton synchrotron, this feeding the entire accelerator complex of ITEP. Development of the first RFQ in the Western world was started at Los Alamos in 1978 and performed a proof-of-principle test in 1980. After that there were many articles and reports and the RFQ became widely known in the world.
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Transparencies
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THOAFI01 | The Development of Computational Tools for Halo Analysis and Study of Halo Growth in the Spallation Neutron Source Linear Accelerator | simulation, linac, emittance, CCL | 2768 | ||||
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Computational tools have been developed to quantify the halo in a beam by analyzing beam profiles and identifying the halo particles using the Gaussian area ratio and kurtosis methods. Simulations of various injection quadrupole magnet configurations using three types of initial simulated distributions, along with an analysis of their phase space and rms properties, provides insight into the development of halo in the Spallation Neurton Source linear accelerator. Finally, comparisons with machine beam profile data, taken at the same conditions as that of the simulated data, show how accurately the simulations model the beam and its halo development and provide a better understanding of the best machine configuration with which to minimize beam halo and losses.
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Transparencies
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THOAFI03 | Global and Local Coupling Compensation in RHIC using AC Dipoles | coupling, RHIC, dipole, sextupole | 2774 | ||||
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Compensation of transverse coupling during the RHIC energy ramp has been proven to be non-trivial and tedious. The lack of accurate knowledge of the coupling sources has initiated several efforts to develop fast techique using turn-by-turn BPM data to identify and compensate these sources. This paper aims to summarize the beam experiments performed to measure the coupling matrix and resonance driving terms with the aid of RHIC ac dipoles.
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Transparencies
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THPCH016 | Transfer Matrix of Linear Focusing System in the Presence of Self-field of Intense Charged Particle Beam | focusing, electromagnetic-fields, dipole, ion | 2817 | ||||
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Within the framework of moments method, the computation algorithm of the transfer matrix in the presence of self-field of the intense charged particle beam is given. The transfer matrix depends on both the linear external electromagnetic field parameters and the initial value of the second order moments of the beam distribution function. In the case of coupled degrees of freedom, the independent 2D subspaces of the whole phase space are found by means of the linear transformation of the phase space variables. The matrix of this transformation connects with second order moments of the beam distribution function. The momentum spread of the beam is taken into account also.
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THPCH028 | Crystalline Beams at High Energies | lattice, dipole, focusing, luminosity | 2841 | ||||
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Previously it was shown that by crystallizing each of the two counter-circulating beams, a much larger beam-beam tune shift can be tolerated during the beam-beam collisions; thus a higher luminosity can be reached for colliding beams*. On the other hand, crystalline beams can only be formed at energies below the transition energy of the circular accelerators**. In this paper, we investigate the formation of crystals in two types of high-transition-energy lattices, one realized by three-cell missing dipole modules and the other with negative bends. The latter type satisfies the maintenance condition for a crystalline beam***.
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*J. Wei and A.M. Sessler, Colliding crystalline beams, EPAC98, p. 862. **J. Wei et al. Physical Review Letters, 73 (1994) p. 3089.***J. Wei et al. Physical Review Letters, 80 (1998) p. 2606. |
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THPCH040 | Linac Focusing and Beam Break Up for 4GLS | focusing, linac, BBU, TESLA | 2871 | ||||
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As part of the design for 4GLS the linac focusing and its effect on the beam break up (BBU) threshold have been studied. The choice of graded gradient focusing scheme is discussed and initial models of the focusing, using a triplet of quadrupoles between each of the modules within the linac, are presented. The quadrupoles were set-up in a defocusing - focusing - defocusing format with strengths of -1/2k, k, -1/2k. Using these models the BBU threshold was computed using available codes assuming a 9-cell TESLA cavity within the linac and a 7-cell design with HOM dampers. A sweep of the magnet strength with respect to the BBU threshold showed that there is an optimum setting.
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THPCH049 | Simulation Study of Transverse Coupled-bunch Instabilities due to Electron Cloud in KEKB LER | electron, simulation, KEKB, positron | 2895 | ||||
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In this paper we report simulation results on the transverse coupled-bunch instabilities (TCBI) due to electron cloud at the KEKB Low Energy Ring (LER). The formation of electron cloud and related TCBI is investigated based on realistic solenoid field model. Studies on electron cloud in Quadrupole which could induce TCBI are also presented in this paper.
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THPCH051 | The Effect of the Solenoid Field in Quadrupole Magnets on the Electron Cloud Instability in the KEKB LER | electron, simulation, KEKB, dipole | 2901 | ||||
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The electron cloud instability which causes vertical beam blowup in the KEKB LER is largely suppressed by applying a weak solenoid field to vacuum chambers in the drift region. However the blowup is still observed when the bunch spacing is reduced to 3.27 rf buckets or shorter. A question is where the remaining electron clouds are. To investigate the electron clouds in the quadrupole magnets, solenoids made of flat cables were developed and installed in 88 quadrupole magnets. The field strength of the solenoid is 17 Gauss. The effect of the solenoid field on the blowup is now under beam study. So far no clear effect of the solenoids on the luminosity and the sideband accompanied by the blowup is found. We report on the solenoid system, the results of the experiments and comparison of the experimental results with simulations.
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THPCH083 | A Tune Feedback System for the HERA Proton Storge Ring | coupling, acceleration, proton, feedback | 2979 | ||||
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The transverse tunes of an accelerator or storage ring are important parameters which have to be controlled and adjusted continuously during beam operation in order to assure good experimental background conditions. For the HERA proton storage ring, persistent current effects of the superconducting magnets are the main source for the inadequate repeatability of the tunes without a feedback while the proton beam is accelerated. A tune feedback has been developed, implemented and tested during beam acceleration and luminosity operation. Considering the different conditions during energy ramps and luminosity runs two versions of this feedback system have been established based on different correction and peak-finding algorithms (e.g. wavelet analysis). No additional excitation is needed on top of the standard tune indication system in HERA. The tunes could be kept constant during beam accceleration with a standard deviation of delta Q = 0.003. In luminosity runs where the tune control is more critical, first tests resulted in a standard deviation which was a factor of ten smaller. The feedback system is implemented as a standard tool for beam acceleration.
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THPCH090 | Stabilization of the ILC Final Focus Using Interferometers | laser, monitoring, target, simulation | 3000 | ||||
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We are developing a system of interferometers that can measure the relative motion between two objects (such as the two final focus quadrupoles) to a few nanometers using interferometric methods. Two instruments are developed at the John Adams Institute at University of Oxford: A distance meter to measure length changes and a straightness monitor to measure perpendicular shifts. We will present technique, results and resolutions of our distance meter prototype. We will also examine their applications at the ILC.
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THPCH112 | High-level Software for Diamond Commissioning and Operation | DIAMOND, booster, storage-ring, controls | 3065 | ||||
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The Diamond accelerator complex is controlled with EPICS. While generic applications are provided by the EPICS toolkit, accelerator physics application for the commissioning and operation of the Diamond booster, storage ring and transfer line are mainly developed with MATLAB. The MATLAB Middle Layer tools developed at ALS and SPEAR3 have been extensively used and extended with many new applications. Experience using these tools during the commissioning of the Diamond booster, transfer lines and storage ring are reported.
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THPCH123 | New Control System for Nuclotron Main Power Supplies | controls, power-supply, extraction, monitoring | 3089 | ||||
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New control and monitoring system for Nuclotron main power supplies was designed in order to substantially extend functionality of the existing equipment and software. The lattice bending (BM), focusing (QF) and defocusing (QD) magnets are powered by two supplies. The BM magnetic field shape is set by pulse function generator that produces a reference burst (Bo-train) with 0.1 Gs resolution. This train controls pattern analog function generator based on a 18-bit DAC. A real B-train from the reference magnet and corresponding analog function are used for feedback loop. The current magnetic field of BM is used as reference function for the focusing and defocusing magnets. A scaling 16-bit multiplied DAC is used to set required ratio IBM/IQFD during accelerator cycle. A 16-bit data acquisition card provides measurement of all analog signals. Digital I/O boards are applied to set and read status of the power supplies, accompanying subsystems and interlocks. Timing modules provide the trigger pulses both for the system internal needs and for synchronizing of the accelerator subsystems and experimental setups.
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THPCH126 | System Development of a Time-of-flight Spectrometer for Surface Analysis of Materials | target, ion, simulation, beam-transport | 3095 | ||||
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To study on design the time-of-flight Rutherford backscattering spectrometry (TOF-RBS) technique for nano-material surface analysis with high resolution. At Fast Neutron Research Facility, FNRF, upgrading of the existing pulsed-beam accelerator from 150-keV of D+$ to 280 keV of He+ was proposed to use for the most powerful method of a near-surface characterization of materials utilizing TOF-RBS. The beam transport was redesigned based on the multicusp ion source which was designed the extraction and focusing system for optimization by the computer program KOBRA, and the existing beam pulsing system to provide He+ ion beam with a few nano-second width and 280-keV acceleration energy. Simulation was done by the computer program Beam Optics, resulting in the beam size at the target position of 1 mm in diameter. The measured beam size was 6 mm in diameter. The optimization of the target position was done by the PARMELA program, to be at 3.14 m from the middle point of the buncher. Components, beam transport characteristics, beam optic simulation, and role of quadrupole magnet were explained. Design and test of the scattering chamber for TOF-RBS were shown and measured by the MCP detector. The quadrupole triplet was designed and constructed at FNRF. Development of TOF-RBS system was implemented in this study. Designing component, fabrication and installation to the accelerator system were completed. Beam extraction and He-scattering tests were done.
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THPCH161 | Status of the Polarized Electron Gun at the S-DALINAC | electron, laser, gun, cathode | 3173 | ||||
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Aiming at an extension of the experimenting capabilities for nuclear structure physics at low momentum transfer at the superconducting Darmstadt electron linear accelerator S-DALINAC, a polarized electron gun is being constructed. The new injector will be able to supply the S-DALINAC with 100 keV polarized electrons and should complement the present, unpolarized thermionic source. The design requirements are a degree of polarization of at least 80%, a mean current intensity of 0.06 mA and a 3 GHz cw structure. The basic design of the gun was adapted from the source of polarized electrons at MAMI, Mainz*, and optimized in various simulations. The active material is a strained layer GaAs crystal which is exposed to an 830 nm pulsed laser beam. We report on the status of the polarized source, the preparation setup and a test beam line.
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*K. Aulenbacher et al., Nucl. Instrum. Meth. A 391, 498 (1997). |
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THPCH164 | Progress and Status of the MICE Project | emittance, coupling, optics, alignment | 3176 | ||||
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The design of a Neutrino Factory (NF) has been the subject of several physics studies. For a NF based on a stored high energy muon beam, a potential key technology that has a significant impact on its cost and practicality is the ability to cool rapidly the muon beam prior to acceleration. The muon ionisation cooling experiment (MICE), currently being constructed at the Rutherford Appleton Laboratory (UK), is a demonstration of emittance cooling in a linear cooling channel. A new muon beam line and the basic infrastructure for MICE are funded, and a muon beam is under construction with an expected availability in spring 2007. The experiment will be methodically assembled over the following few years to bring the beam through RF accelerating cavities and liquid hydrogen absorbers and confined by a solenoidal magnetic field. The emittance of the beam before and after the cooling channel is measured in tracking spectrometers. The current status of the beam line and infrastructure build and of the components of MICE is presented.
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THPCH180 | Equipment for Tunnel Installation of Main and Insertion LHC Cryo-magnets | LHC, acceleration, monitoring, dipole | 3218 | ||||
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The installation of about 1700 superconducting dipoles and quadrupoles in the Large Hadron Collider (LHC) is now well underway. The transport and installation of the LHC cryo-magnets in the LEP tunnels originally designed for smaller, lighter LEP magnets have required development of completely new handling solutions. The severe space constraints combined with the long, heavy loads have meant that solutions had to be very sophisticated. The paper describes the procedure of the installation of the main cryo-magnets in the arc as well as the more specific insertion cryo-magnets. The logistics for the handling and transport are monitored with tri-axial acceleration monitoring devices that are installed on each cryo-magnet to ensure their mechanical and geometric integrity. These dynamic results are commented. The paper includes conclusions and some lessons learned.
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THPCH192 | Experimental, Test and Research Beamlines at Fermilab | proton, linac, target, controls | 3242 | ||||
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Three new external beamlines are in operation or under development at Fermilab: 1) the Main Injector Particle Production (MIPP) beamline, 2) the Mucool Test Area (MTA) beamline, and 3) a new MTEST beamline for advanced detector work for high energy experiments and the ILC. The MIPP beamline is a secondary production beamline capable of producing well-characterized beams of protons, pions, and kaons from 5-120 GeV/c using 120 GeV/c protons from the Fermilab Main Injector. The second line is a new primary 400-MeV proton beamline derived from the 400 MeV proton Linac which will provide for precision measurements of Linac beam parameters in addition to a high-intensity primary test beam for development and verification of muon ionization cooling apparatus. A dual mode operation will also provide accurate, dispersion-free measurements of the Fermilab Linac beam properties with potential for diagnostic development. Installation is planned in 2007. Finally, a third beam is also under design to provide secondary beams at ultra-low - high energies, from ~1 GeV/c to 90 GeV/c in addition to a primary 120-GeV proton mode of operation. It is anticipated that this last line will be installed in fall of 2006.
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THPLS005 | Commissioning Results from the Injection System for the Australian Synchrotron Project | injection, booster, synchrotron, emittance | 3272 | ||||
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Danfysik has built a full-energy turnkey injection system for the Australian Synchrotron. The system consists of a 100 MeV LINAC, a low-energy transfer beamline, a full-energy booster and a high energy transfer beamline. The booster synchrotron will deliver a 3-GeV beam with an emittance of 33 nm. The lattice is designed to have many cells with combined-function magnets (dipole, quadrupole and sextupole fields) in order to reach this very small emittance. The current in single- and multi-bunch mode will be in excess of 0.5 and 5 mA, respectively. The repetition frequency will be 1 Hz. At the time of writing this abstract, the LINAC beam has been injected into the low-energy transfer beamline. The project is on schedule for delivery in April 2006. Results from the commissioning of the system will be presented together with its performance.
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THPLS006 | The Machine Installation at SOLEIL | alignment, SOLEIL, vacuum, dipole | 3275 | ||||
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SOLEIL is a third generation Synchrotron radiation Source, under construction in France near Paris. The 357 m circumference storage ring is mainly composed of (32 +1) dipoles, 160 quadrupoles, 120 sextupoles, 2 RF cryomodules, ~ 200 vacuum chambers, 6 injection equipment; 12 beamline front-ends and 4 insertion devices (initially). The 157 m circumference Booster comprises 36 dipoles, 44 quadrupoles, 28 sextupoles, 1 RF cavity and 8 injection/extraction equipment. Before the beginning of the Process installation, a general planning was established detailing the various stages of the equipment installation and their assembly protocols before their on-site installation. In reality, many unknown factors, delays on the buildings, delays on the equipment deliveries, technical problems encountered during the construction, have constrained us to significantly and frequently amend and adapt this initial planning. Due to the various delays, it was also necessary to manage the cohabitation with the various building trades. However, the work made on the initial planning paid off as without its detailed protocols, we could not have carried out the Process installation within correct deadline.
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THPLS007 | Magnetic Measurements Results of the Dipoles, Quadrupoles and Sextupoles of the SOLEIL Storage Ring | dipole, SOLEIL, sextupole, storage-ring | 3278 | ||||
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During the magnetic measurement campaign, from May 2004 to August 2005, the 326 electro-magnets of the SOLEIL Storage Ring have been characterized in terms of magnetic axis centering and field properties. For the dipoles, two types of measurements have been performed at SOLEIL: field mapping in the mid plan using a Hall probes bench, and field integral comparison with a reference magnet using a stretched wire bench. For the quadrupoles, a rotating coil bench has been built and optimized at SOLEIL in order to reach magnetic center and tilt angle adjustments within ± 25 μm and ± 0.1 mrad respectively. For the sextupoles, magnetic measurements have been performed by the SIGMAPHI Company. This paper will present the main features of the SOLEIL benches, the results of magnetic measurements in terms of reproducibility, field identity between magnets, magnetic axis centering, and harmonic content versus current. Moreover, the origin of some unexpected harmonic field components will be discussed, as well as the magnetic compensation scheme used to minimize some of them.
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THPLS009 | First Results of the Commissioning of SOLEIL Storage Rings | storage-ring, SOLEIL, injection, closed-orbit | 3284 | ||||
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The commissioning of SOLEIL's storage ring will start in April 2006. The objective is to reach, within a first phase of two months, stable beam conditions at 100 mA in the multi-bunch mode that can be used for the commissioning of the beamlines. This is a challenging objective, especially because the SOLEIL's ring is incorporating some innovative techniques such as the use of a superconducting RF cavity, NEG coating for all straight parts of the machine and new BPM electronics. Prior to the start of the commissioning, some insertion devices and most of the insertion devices low gap vacuum vessels, including 10 mm inner vertical aperture vessels for the Apple-II type, will be installed on the ring. This paper will review the performances of all these equipment in presence of the beam. The results of the first commissioning runs will be presented.
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THPLS010 | Metrology for the Beam Emittance Measurement of the SOLEIL Injector | emittance, booster, linac, SOLEIL | 3287 | ||||
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The injector system of SOLEIL is composed of a 100 MeV electron linac pre-accelerator followed by a full energy 2.75 GeV booster synchrotron, operating at 3 Hz. Dedicated diagnostics such as emittance monitors are installed on the two transfer lines between the linac and the booster and between the booster and the storage ring. The measurement is performed using the gradient method, relying on YAG screens and high resolution CCD cameras. This paper will show the metrology of the emittance measurements which were made for the HELIOS (THALES) iinac beam (total emittance in the range of 1 μm.rad) and for the booster beam (rms emittance ~ 150 nm.rad): error sources are identified and specific corrections are shown. Additional analysis of the dynamics of the injection into the booster and into the storage ring is made for a deeper characterization.
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THPLS013 | The Magnets of the Metrology Light Source in Berlin-Adlershof | dipole, sextupole, storage-ring, octupole | 3296 | ||||
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PTB, the German National Metrology Institute in close cooperation with BESSY II, is currently carrying out the project of constructing the low-energy "Metrology Light Source" (MLS) as a synchrotron radiation facility situated in the close vicinity of BESSY II. Construction of the MLS housing is in progress and nearly finished. The user operation is scheduled to begin in 2008. Dedicated to metrology and technology development in the UV and EUV spectral range, the MLS will bridge the gap that is existent since the shutdown of BESSY I. A 100 MeV microtron delivered by Danfysik A/S will provide the electrons for the MLS with a structure of asymmetric double bend achromat. The total circumference of the MLS is 48 m. The electron energy is ramped to the desired value between 200 MeV and 600 MeV. The MLS magnetic lattice, consisting of 8 bending magnets, 24 quadrupole magnets, 24 sextupole magnets and 4 octupole magnets, is laid out to facilitate this operation. The contract for the MLS magnets is awarded to the Budker Institute for Nuclear Physics. A description of the MLS magnets based on the results of the factory acceptance tests should be presented.
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THPLS024 | Controlling the Vertical Emittance Coupling in CAMD | coupling, wiggler, TESLA, resonance | 3329 | ||||
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The vertical beam size in the CAMD Light Source, as measured with an x-ray pinhole camera, indicates an emittance coupling ratio of 3%. This is consistent with the coupling ratio as measured by the betatron tune split when the coupling resonance is fully engaged. It has been shown that the coupling is mainly produced in the 7T wiggler, which is known to produce non-linear fields. To correct this coupling, it is proposed to install up to four skew quadrupoles. The results of testing a prototype skew quadrupole in the lattice are presented. It is shown that the coupling will be substantially corrected by suitably distributing and powering the four skew quadrupoles.
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THPLS030 | Beam Optic Measurements for the Booster Synchrotron of the Diamond Light Source | booster, injection, lattice, DIAMOND | 3347 | ||||
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The booster synchrotron of the Diamond Light Source is a full energy injector ramping from 100 MeV to 3 GeV with a repetition rate of 5 Hz. As part of the booster commissioning, beam optic measurements were performed to characterize the booster performance. Through the use of the beam position monitors, orbit corrections, tune and chromaticity measurements were performed at injection energy and during the ramp. A first comparison with the booster model is also discussed.
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THPLS033 | Elettra New Full Energy Injector Status Report | booster, ELETTRA, dipole, storage-ring | 3356 | ||||
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The Elettra new full energy injector will be based on a 100 MeV linac pre-injector, a 2.5 GeV booster synchrotron and two new beam transfer lines. It will replace the existing 1.2 GeV linac injector and transfer line. Full funding was finally available in 2005, which allowed to start, or in some cases to re-start, the construction activities. The status of the project will be presented in this paper, in particular the progress of the fabrication of various components, like magnets, power supplies, vacuum chambers; also the status of the construction of the building and technical plants will be given. Results of recent optimization studies will also be outlined. The commissioning of the new injector is scheduled to start in Spring 2007, while the first ELETTRA operation for user's with the new full energy injector is expected for the last quarter of 2007.
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THPLS048 | Beam-optics Analysis and Periodicity Restoration in the Storage Ring of the Pohang Light Source | storage-ring, optics, dynamic-aperture, focusing | 3395 | ||||
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The PLS is a third-generation synchrotron radiation source, which provides intense light from ultraviolet to soft x-rays. Similar to other light sources, the PLS is characterized by a small emittance in order to achieve a very high spectral brightness and stably circulating electron beam. To guarantee these characteristics, a thorough understanding of the linear optics has to be carried out, and many storage rings employ LOCO (Linear Optics from Closed Orbits) to analyse the linear optics. This paper will describe the LOCO implementation at PLS and the results.
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THPLS054 | Closed Orbit Correction and Beam Dynamics Issues at ALBA | lattice, multipole, dynamic-aperture, vacuum | 3404 | ||||
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ALBA is a 3 GeV light source being built in Spain. The light source should be operational in 2010.The lattice for the storage ring is now finalized. The basic cells is an extended DBA-like structure with finite dispersion in the straight sections, providing low emittance (under 5nmrad) , small beam cross sections at the source points (less than 150 micro-m horizontal and 10micro-m vertical), and a large number of straight sections (4 times 8m, 12 times 4.2m and 8 times 2.6m). In this paper we review the properties of the lattice with special emphasis in the closed orbit correction system and the lifetime limits.
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THPLS057 | Injector Design for ALBA | booster, linac, dipole, storage-ring | 3413 | ||||
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The storage ring ALBA is a 3rd generation synchrotron light source under construction in Barcelona (Spain). The facility is based on a 3.0 GeV storage ring of 268.8 m circumference with a beam emittance under 5 nm.rad. Top-up operation is foreseen from the start. The injector complex for ALBA will consist of a 100 MeV linac and a full energy booster. The linac will be a turn-key system which has already been ordered to the industry and delivery is expected in the second half of 2007. The full energy booster will be placed in the same tunnel as the storage ring and will have a circumference of 249.6 m. The lattice of the booster is a modified FODO lattice providing an emittance as low as 9 nm.rad. The magnet system comprises 40 combined magnets and 60 quadrupoles. Chromaticity correction relies on the sextupole component built-in the combined magnets and the quadrupoles. In this paper a description of the booster design including the present status of the different components will be given.
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THPLS067 | Vertical Beam Size Control in TLS and TPS | coupling, emittance, feedback, betatron | 3442 | ||||
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Vertical beam size control is an important issue in the light source operations. The horizontal-vertical betatron coupling and vertical dispersion were measured and corrected to small values in the TLS 1.5 GeV storage ring. Estimated beam sizes are compared with the measured values. By employing an effective transverse damping system, the vertical beam blow-up due to transverse coherent instabilities such as the fast-ion beam instability was suppressed and as a result, the light source is very stable. In NSRRC we are designing an ultra low emittance 3-GeV storage ring and its designed vertical beam size could be as small as a few microns. The ground and mechanic vibration effects, and coherent instabilities could spoil the expected photon brightness due to blow-up of the vertical beam size if not well taken care of. The contributions of these effects to vertical beam size increase will be evaluated and the counter measures to minimize them will be proposed and reported in this paper.
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THPLS075 | Progress in Development of Kharkov X-Ray Generator | storage-ring, injection, electron, lattice | 3457 | ||||
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Over the past year the design, development and construction of NSC KIPT X-ray generator NESTOR has been in progress. NESTOR is a new type radiation source on the base of Compton scattering and a 40 - 225 MeV electron storage ring. Electrons are injected in the storage ring at 100 MeV and ramped up to final energy 225 MeV. It is supposed that stored electron beam current will be of about 200 mA. Along with use of Nd:Yag laser of 10 W average power which was developed by High-Q laser firm and optical resonator with accumulation gain of about 1000 it allows to provide X-ray radiation flux up to 1011 phot/s. NESTOR is the cooperative facility and is supported both as well Ukrainian government as NATO SfP project #977982. It is supposed that NESTOR will be in operation in the middle of 2007 year. The status of the project and main facility systems are described in the report.
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THPLS083 | Implementation of the Double-waist Chicane Optics in SPEAR 3 | optics, lattice, dipole, vacuum | 3472 | ||||
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The SPEAR 3 upgrade produced two new 7.6 m racetrack straight sections in the 18 cell, 234 m magnet lattice. One of these straights houses four PEP-II style mode-damped RF cavities. The other straight will accommodate two new small-gap insertion devices separated by 10mrad in a magnetic chicane configuration. A quadrupole triplet has been installed at the midpoint of the chicane and the vertical tune has been raised by an integer to create a 'double waist' optics with betay = 1.6m in the center of each ID. Furthermore, as part of the optics upgrade, betay in the four straights adjacent to the racetrack sections was reduced from 5m to 2.5m. In this paper, we describe the physical implementation of the double-waist chicane optics and initial operational results.
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THPLS088 | Optimizing the Dynamic Aperture for Triple Bend Achromatic Lattices | lattice, emittance, dipole, sextupole | 3481 | ||||
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The Triple Bend Achromatic (TBA) lattice has the potential for lower natural emittance per period than the Double Bend Achromatic (DBA) lattice for high brightness light sources. However, the DBA has been chosen for 3rd generation light sources more often due to the higher number of undulator straight section available for a comparable emittance. The TBA has considerable flexibility in linear optics tuning while maintaining this emittance advantage. We have used the tune and chromaticity flexibility of a TBA lattice to minimize the lowest order nonlinearities using a high order achromatic tune condition, while maintaining a constant emittance. This frees the geometric sextupoles to counter the higher order nonlinearities. This procedure is being used to improve the nonlinear dynamics of the TBA as a proposed lattice for the NSLS-II facility. The flexibility of the TBA lattice will also provide for future upgrade capabilities of the beam parameters.
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THPLS091 | Control of Dynamic Aperture with Insertion Devices | lattice, optics, dynamic-aperture, sextupole | 3490 | ||||
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It is well known that insertion devices (IDs) perturb the linear optics in the vertical plane. In particular, that the effect can be corrected locally by a symmetric arrangement of four quadrupoles on each side of the IDs. We show how to control an arbitrary set of IDs in this configuration with the response matrix for the beta-beat and perturbation of the phase advance and SVD, i.e., to maintain the dynamic aperture. We also evaluate the residual impact on the dynamic aperture from the nonlinear terms and outline how to control these. As an example, we discuss an impact of some ID models on the NSLS-2 dynamic aperture. Results for a single ID and a set of 20 IDs with random field strengths are presented.
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THPLS107 | Possibility of the Beam Injection Using a Single Pulsed Sextupole Magnet in Electron Storage Rings | injection, sextupole, electron, storage-ring | 3526 | ||||
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Recently, we succeeded in the beam injection using a single pulsed quadrupole magnet (PQM) at the Photon Factory Advanced Ring (PF-AR). The PQM enables us to inject the beam into the storage ring without the local bump by several pulsed dipole magnets. In addition, since the stored beam is not kicked when the beam passes through the magnetic center of the PQM, we can avoid the coherent beam oscillation, which is often produced by the unclosed local bump. It is important for the top-up injection in electron storage rings as synchrotron radiation sources. However, in the case of the PQM, we have the problem that the beam profile slightly changes turn-by-turn after the excitation of the PQM. In order to solve it, we investigated the possibility of the beam injection using a single pulsed sextupole magnet (PSM) instead of the PQM. Here, we will present the simulation of the beam injection using the PSM.
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THPLS127 | Plans for a 2nd Insertion Device in CAMD | wiggler, multipole, lattice, TESLA | 3583 | ||||
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To allow the possible installation of a 2nd Insertion Device in the CAMD Light Source the lattice optic needs to be changed. The present configuration has a small vertical beta function in the long straight containing the 7T wiggler. The new optic will give small vertical beta at two long straights which are diametrically opposite. Test results with the new optic are presented together with the measured beam parameters. These are used to predict the photon beam performance for several types of Insertion Device which could be installed.
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