IMP, Lanzhou
Advancement of nuclear physics and high power heavy ion accelerator is always a driving force for persistent development of highly charged ECR ion source. Increasing demands for more intense and higher charge state heavy ion beams have dramatically promoted development of ECR ion source technology and physics. This talk provides an overview of intense highly charged superconducting ECR ion sources built by the world-wide laboratories in the last years. The key technologies, challenges and main issues related to construction and operation of high performance superconducting ECR ion source are reviewed. The latest results of intense highly charged ion beam production from the superconducting ECR ion sources are presented. Future development and the next generation highly charged ECR ion source are discussed.
CERN, Geneva
University of Malta, Faculty of Engineering, Msida
The relation between field and current in each family of the Large Hadron Collider magnets is modeled with a set of empirical equations (FiDeL) whose free parameters are fitted on magnetic measurements. They take into account of residual magnetization, persistent currents, hysteresis, saturation, decay and snapback during initial part of the ramp. Here we give a first summary of the reconstruction of the magnetic field properties based on the beam observables (orbit, tune, coupling, chromaticity) and a comparison with the expectations based on the large set of magnetic measurements carried out during the 5-years-long production. The most critical issues for the machine performance in terms of knowledge of the relation magnetic field vs current are pinned out.
CLS, Saskatoon, Saskatchewan
Storage rings require corrector magnets for a variety of tasks. Foremost are small dipole magnets for both horizontal and vertical correction. In light sources, for example, other corrector magnets are needed to compensate for the effect of changing insertion device operation points. These can include quadrupole, skew quadrupole, sextupole and skew sextupole corrections. As well octupole magnets may be desirable to improve dynamic aperture in small emittance lattices. One magnet can perform all these tasks. This is achieved by having separate windings with separate power supplies on an octopole yoke. The simultaneous excitation of any combination of modes can be achieved through superposition. Corrections are necessarily limited to avoid saturation effects that will degrade the superposition.
CNAO Foundation, Milan
CERN, Geneva
LPSC, Grenoble
INFN/LNF, Frascati (Roma)
CNAO is a synchrotron accelerator presently under commissioning in Pavia. The aim of this accelerator is to treat tumors with hadrons and to perform advanced clinical and radiobiological research. The CNAO will start treating patients with protons (60-250 MeV range) and carbon ions (120-400 MeV/u range) in three treatment rooms with four beam lines. Future upgrade with gantries is foreseen. This paper describes the design, magnetic measurements and sorting criterion used for the sixteen synchrotron main dipoles and twenty-four quadrupoles. The magnetic measurements results are compared with magnetic simulation.
NewSUBARU/SPring-8, Laboratory of Advanced Science and Technology for Industry (LASTI), Hyogo
A multi-element octupole-base corrector magnet is designed and fabricated. The new corrector magnet will be installed in the electron storage ring NewSUBARU in place of vertical steering (skew dipole) magnets. It has coil windings to produce skew quadrupole, skew sextupole, normal octupole, and the skew dipole field. The skew dipole element is used to achieve vertical steering. The skew quadrupole and the skew sextupole elements are for the resonance correction. The normal octupole element is used to control the higher order dispersion function and the higher order momentum compaction factor. In this design the main coil is wound around the return yoke instead of the pole. We expect improvement of the beam lifetime and injection efficiency during normal operation as well as improved isochronism during extreme quasi-isochronous operation. In designing the magnet, careful consideration is given to field interference caused by a neighboring magnet, set close to the corrector magnet of comparable yoke and bore diameter dimensions. The magnetic field with field interference is calculated using OPERA-3D.
KEK, Ibaraki
MELCO SC, Tsukuba
J-PARC, KEK & JAEA, Ibaraki-ken
Efforts have been made to reduce the magnetic field ripple of the bending, quadrupole and sextupole magnets of the J-PARC main ring using the trim coils of the magnets. The quadrupole magnet has 24 turn main coil and 11 turn trim coil per pole those can be considered as a primary winding and a secondary winding of a transformer. When the trim coil is shorted, the induced trim coil current cancels the field ripple. The field ripple of the quadrupole magnet was reduced by a factor of 6 by shorting trim coil. The trim coil current, however, deforms the acceleration field pattern if the coil is shorted all the time of the current pattern of flat bottom, acceleration, flat top and recovery. The MOSFET relay was used to short the coil and to reduce the field ripple during the flat bottom and flat top. The circuits were built for the quadrupole and sextupole magnets. The plan has been made to wind optimized trim coils for the bending magnets.
PAL, Pohang, Kyungbuk
Pohang Light Source (PLS) is planning a major upgrade of the storage ring to meet the more demanding requirement from the synchrotron light users. The main features of the major upgrade are (1) increasing the electron beam energy from 2.5 GeV to 3.0 GeV for more higher energy X-ray photons, (2) decreasing the electron beam emittance from 1.89 nm to 5.8 nm to increase the photon brilliances, and (3) increasing the number of straight sections to install the insertion devices from 10 to 20 to meet the demand for insertion devices. in the upgraded PLS (PLS-II), there will be 24 combined function dipole magnets, 96 quadrupole magnets, and 144 sextupole magnets with some auxiliary magnets for electron beam injection. In this report, the physical design features, mechanical aspects of the magnet design are described.
CERN, Geneva
U. Sannio, Benevento
One of the main requirements for the operation of the Large Hadron Collider at CERN is the correction of the dynamic multipole errors produced in the main magnets*. In particular, integrated sextupole errors in the main dipoles must be kept well below 0.1 units to ensure acceptable chromaticity. The feed-forward control of the LHC is based on the Field Description for the LHC (FiDel), a semi-empirical mathematical model capable of forecasting the magnet's behaviour in order to generate suitable corrector current waveforms. Measurement campaigns were recently undertaken to validate the model making use of a novel fast rotating-coil magnetic measurement system (FAME)**, able to detect superconductor decay and snapback transients with unprecedented accuracy and temporal resolution. In this paper we discuss the test setup and the results obtained both on the test bench and in the actual operation of the accelerator.
* P. Xydi et al, "A Demonstration Experiment For The Forecast Of Magnetic Field … ", EPAC 2008
** N. R. Brooks et al, "Estimation Of Mechanical Vibration Of …", IEEE TAS 2008
NSRRC, Hsinchu
Taiwan Photon Source (TPS) is a new third generation synchrotron storage ring with energy 3 GeV, which consists of 24 double-bend cells and its circumference is 518.4 m. Various accelerator lattice magnets which consist of 48 bending magnets, 240 quadrupoles and 168 multifunction sextupole magnets. All magnets pole profiles, edge shim and magnet end chamfer were designed in TOSCA and RADIA magnetic computation code. In order to verify the magnetic field quality of computation code, prototype magnets have been manufactured in this year. Two measurement systems, hall probe and rotating coils, were used for magnetic field mapping. This paper presents magnetic field mapping results of prototype magnets and compared with original magnetic circuit designs.
NSRRC, Hsinchu
The free space between magnets of TPS storage ring is very tight, especially the space between quadrupole and sextupole magnets. The minimum space between the yoke of quadrupole and sextupole is about 150mm, and the space between coils is only 10mm. In this case, the significant magnetic field distortions could have an impact on the performance of machine. Two magnets simulation compare to the individual magnet were performed in TOSCA 3D model. The crosstalk effect shows that the sextupole component increases from 0.0004% to 0.04% in the quadrupole magnet and the quadrupole component increases from 0.0008% to 0.06% in the sextupole magnet. We discuss this crosstalk effect and how to decrease the effect with appropriate shielding.
CEA, Gif-sur-Yvette
S3 (Super Separator Spectrometer) [1] is a future device designed for experiments with the very high intensity heavy ion stable beams of SPIRAL2. It will be set-up at the exit of the linear accelerator LINAG at GANIL (Caen, France). It will include a target resistant to very high intensities, a first stage momentum achromat for primary beam suppression, a second stage mass spectrometer and a dedicated detection system. This mass spectrometer includes a set of four large aperture quadrupole triplets with embedded multipolar corrections. These magnets are a combination of three multipoles which could be realized with superconductor wound in flat racetrack coils. To enable the primary beam extraction one triplet has to be opened on one side, which requires a careful design of such a multipolar magnet. This paper describes the opened multipole geometry. It is adapted to large apertures as demonstrated by Opera 3d© magnetic simulations [2], including harmonic analysis and integral field homogeneity.
GSI, Darmstadt
JINR, Dubna, Moscow Region
TEMF, TU Darmstadt, Darmstadt
Superconducting magnets are planned to be installed at the SIS100 accelerator ring for FAIR. The error compensation multipole corrector and the steerer are built as nested magnets to save longitudinal space in the ring, the chromaticity sextupole is a superferric magnet. We present the dynamic field quality of the SIS100 dipole and the vacuum chamber deterioration next to the 2D and 3D field quality of the multipole corrector and of the chromaticity corrector. The quality of the injection field of the SIS100 dipole is mainly dominated by eddy currents as soon as the field ramp starts. We show its AC losses concerning the hydraulic limits for cooling the magnet with forced two phase helium flow and conclude on the maximum chromaticity correction which is feasible for the foreseen magnet design. The results are discussed in respect of recent beam dynamic calculations on the ramp.
TEMF, TU Darmstadt, Darmstadt
For the computation of the electromagnetic fields in large accelerator components, such as the superconducting dipole magnets to be installed in the heavy-ion synchrotron SIS100 at GSI, Darmstadt in context of the FAIR project, very large numerical models are required. By using parallelization techniques in combination with higher-order finite element approaches, full 3D solutions for the complicated geometry can be obtained in reasonable computational time. This is important, in particular, if repeated simulations need to be performed as in case of the determination of the sensitivity of the results to parametric changes, e.g. due to manufacturing tolerances. For that purpose, a parallelized 3D simulation tool is developed and applied to the prototype of the SIS100 dipole magnet. The results for the field quality during transient operation considering eddy currents in the conductive parts of the assembly are reported.
Kyoto ICR, Uji, Kyoto
ILL, Grenoble
RID, Delft
ANL, Argonne
KURRI, Osaka
RIKEN, Wako, Saitama
ANSTO, Menai
KEK, Ibaraki
We have developed a motorized magnetic lens for focusing of pulsed white neutron beams. The lens is composed of two concentric permanent magnet arrays, in sextupole geometry, with bore of 15 mm and magnet length of 66 mm. The inner magnet array is stationary, while the outer array is rotated (the frequency of the modulation of magnetic field inside the bore ν ≤ 25Hz), providing a sextupole magnetic field gradient range of 1.5x104T/m2 ≤ g' ≤ 5.9x104T/m2. By synchronization of a pulsed neutron beam with the sinusoidal modulation of the magnetic field in the lens, the beam is focused, without significant chromatic aberration, over a wide neutron wavelength band. We have constructed a focusing-SANS (Small Angle Neutron Scattering) test bed on the PF2-VCN (Very Cold Neutron) beam line at the Institut Laue-Langevin in Grenoble. The beam image size matched the source size (≈ 3mm) over of wavelength range of 30Å ≤ λ ≤ 48Å with focal length of ~ 2.3 m. Further, we have demonstrated the performance of this device for high resolution time-of-flight (tof) SANS for a selection of polymeric & biological samples, in a compact geometry of just 5 m.
CERN, Geneva
BNL, Upton, Long Island, New York
During the 2009 LHC injection tests, the polarities and effects of specific quadrupole and higher-order magnetic circuits were investigated. A set of magnet circuits had been selected for detailed investigation based on a number of criteria. On or off-momentum difference trajectories launched via appropriate orbit correctors for varying strength settings of the magnet circuits under study - e.g. main, trim and skew quadrupoles; sextupole families and spool piece correctors; skew sextupoles, octupoles - were compared with predictions from various optics models. These comparisons allowed confirming or updating the relative polarity conventions used in the optics model and the accelerator control system, as well as verifying the correct powering and assignment of magnet families. Results from measurements in several LHC sectors are presented.
JINR, Dubna, Moscow Region
Fermilab, Batavia
FZJ, Jülich
Main element of the NICA facility is the collider equipped with stochastic and electron cooling systems to provide experiment with heavy ions like Au, Pb or U at energy from 1 to 4.5 GeV/u with average luminosity of the level of 1027 cm-2 s-1. The possible lattices providing the required parameters are discussed.
JINR, Dubna, Moscow Region
Cockcroft Institute, Warrington, Cheshire
The Ultra-Low energy Storage Ring (USR) within the future Facility for Low-energy Antiproton and Ion Research (FLAIR) will decelerate antiproton beams from 300 keV to energies of only 20 keV. Cooled beams will then be extracted and provided to external experiments. The large variety of planned experiments requires a highly flexible longitudinal time structure of the extracted bunches, ranging from ultra-short pulses in the nanosecond regime to quasi DC beams. This requires fast as well as slow extraction in order to cover whole range of envisaged beam parameters. A particular challenge was to combine elements for fast and slow extraction in one straight section of this electrostatic ring. In this contribution we present the results of beam dynamic simulations and describe the overall extraction scheme in detail.
CERN, Geneva
SMI, Vienna
The hyperfine transition frequency of hydrogen is known to a very high precision and therefore the measurement of this transition frequency in antihydrogen is offering one of the most accurate tests of CPT symmetry. The ASACUSA collaboration will run an experiment designed to produce ground state antihydrogen atoms in a CUSP trap. These antihydrogen atoms will pass with a low rate in the order of 1 per second through a spin-flip cavity where they get excited depending on their polarization by a 1.42 GHz magnetic field. Due to the small amount of antihydrogen atoms that will be available the requirement of good field homogeneity is imposed in order to obtain an interaction with as many antihydrogen atoms as possible. This leads to a requirement of an RF field deviation of less than ± 10 % transverse to the beam direction over a beam aperture with 100 mm diameter. All design aspects of this new spin-flip cavity, including the required field homogeneity and vacuum aspects, are discussed.
SLAC, Menlo Park, California
INFN/LNF, Frascati (Roma)
BINP SB RAS, Novosibirsk
The Super-B asymmetric e+e- collider is designed for 1036 cm-2sec-1 luminosity and beam energies of 6.7 and 4.18 GeV for e+ and e-, respectively. The machine will have the High and Low Energy Rings (HER and LER), and one Interaction Point (IP) with 60 mrad crossing angle. The INFN-LNF at Frascati is one of the proposed sites, and a lattice for short 1.3 km rings fitting to this site has been designed. The two rings are radially separated by 2 m except near the IP and in the dogleg on the opposite side of the rings. The injection sections and RF cavities are included. The lattice is optimized for a low emittance required for the desired high luminosity. Final Focus chromaticity correction is optimized for large transverse and energy acceptance. The "crab waist" sextupoles are included for suppression of betatron resonances induced at the IP collisions with large Piwinski angle. The LER spin rotator sections provide longitudinal polarization for the electron beam at IP. The lattice is flexible for tuning the design parameters and compatible with reusing the PEP-II magnets, RF cavities and other components. Design criteria and details on the lattice implementation are presented.
University of Pisa and INFN, Pisa
INFN/LNF, Frascati (Roma)
SLAC, Menlo Park, California
SuperB is an international project for an asymmetric 2 rings collider at the B mesons cm energy to be built in the Rome area in Italy. The two rings will have very small beam sizes at the Interaction Point and very small emittances, similar to the Linear Collider Damping Rings ones. In particular, the ultra low vertical emittances, 7 pm in the LER and 4 pm in the HER, need a careful study of the misalignment errors effects on the machine performances. Studies on the closed orbit, vertical dispersion and coupling corrections have been carried out in order to specify the maximum allowed errors and to provide a procedure for emittance tuning. A new tool which combines MADX and Matlab routines has been developed, allowing for both corrections and tuning. Results of these studies are presented.
KEK, Ibaraki
A new set of magnets, skew sextupole magnets, were designed, manufactured, measured and installed during the winter shutdown of 2009. Twenty magnets were installed in the HER and eight magnets were installed in the LER. It was a challenging job for the magnet group to design, manufacture, measure the magnetic field and install them in the tunnel in just three months. Much effort to finish the installation in time and reduce the production cost was made at every step of the entire process. With these newly installed skew sextupole magnets, a significant luminosity boost was achieved. The production and installation of the skew sextupole magnets are described in this report.
KEK, Ibaraki
Progress of Graphic Processor Unit (GPU) is marveled. The performance is 1TFlops per unit. Simulation of electron gun can be performed by particle-particle interactions, in which the calculation cost is NxN. Since the calculation of each interaction is very simple, GPU can demonstrate its ability. We show simulation results and discuss the possibilities to extend other simulations.
Fermilab, Batavia
Muon collider is a promising candidate for the next energy frontier machine. However, in order to obtain peak luminosity in the 1035/cm2/s range the collider lattice design must satisfy a number of stringent requirements, such as low beta at IP (beta*<1 cm), large momentum acceptance and dynamic aperture and small value of the momentum compaction factor. Here we present a particular solution for the interaction region optics whose distinctive feature is a three-sextupole local chromatic correction scheme. Together with a new flexible momentum compaction arc cell design this scheme allows to satisfy all the above-mentioned requirements and is relatively insensitive to the beam-beam effect.
CASA, newport news
JLAB, Newport News, Virginia
The proposed electron collider lattice exhibits low β- functions at the Interaction Point (IP) (βx∗100mm − βy∗ 20 mm) and rather large equilibrium momentum spread of the collider ring (δp/p = 0.00158). Both features make the chromatic corrections of paramount importance. Here the chromatic effects of the final focus quadruples are cor- rected both locally and globally. Local correction features symmetric sextupole families around the IP, the betatron phase advances from the IP to the sextupoles are chosen to eliminate the second order chromatic aberration. Global interleaved families of sextupoles are placed in the figure-8 arc sections, and non-interleaved families at straight sec- tion making use of the freely propagated dispersion wave from the arcs. This strategy minimizes the required sex- tupole strength and eventually leads to larger dynamic aper- ture of the collider. The resulting spherical aberrations induced by the sextupoles are mitigated by design; the straight and arc sections optics features an inverse identity transformation between sextupoles in each pair.
IHEP Beijing, Beijing
Optics correction is an important issue at BEPCII. Due to the errors in all kinds of components of a storage ring, the real optics of a storage ring is different from the design one. This paper introduces some developments of optics calibration at BEPCII storage ring. We use the method that fit the measured response matrix to the model response matrix to get the fudge factor of the quadrupole field and the sextupole field. On the other hand, in considering fringing fields of quadrupole magnet and interaction of quadrupole magnet iron core and sextupole magnet iron core, the model is calibrated.
LBNL, Berkeley, California
For quadrupole or sextupole magnets, the field at the center is zero and will not disturb the stored beam, while the field away from the center increases in magnitude, giving a larger kick to the particles off axis. By pulsing such multipole magnets it is possible to improve the injection efficiency of the Advanced Light Source (ALS) in top off mode. The requirements for a multipole pole kicker injection scheme for ALS are to kick a 1.9 GeV beam by an angle of 10 mrad with a magnet of 1 meter length. Both quadrupole and sextupole magnets have been studied, as well as a dipole magnet with non-constant field magnitude across the center of the aperture. This paper describes the design and gives a comparison of each type of magnet as well as the modulators needed to drive them.
Royal Holloway, University of London, Surrey
Serpentine is a Python library, written for the purpose of simulating charged particle accelerators. It has been written to allow for the simulation of both rings and single-shot machines in a light-weight way (i.e. without requiring significant computational resources for typical calculations, such as the determination of transfer matrices, or matching of Twiss parameters), and has been structured to be highly modular (i.e. allowing extension of the simulations to include effects not already included in the base installation). Through the use of the Universal Accelerator Parser (UAP), Serpentine has no need for a new lattice representation, and allows access to any lattice format understood by UAP. The operation of this code on several complex accelerator designs is demonstrated.
KEK, Ibaraki
J-PARC, KEK & JAEA, Ibaraki-ken
During the early J-PARC Main Ring commissioning and the machine operation with the moderate beam power the 'fast extraction' bare working point has been chosen to provide the machine operation in the safe regime. We discuss main experimental results obtained so far and compare with the results of the computational model of the machine, including the first experimental approach to minimize the effect of the 'sum' linear coupling resonance. The strategy to increase the beam power without changing the operational working point is presented by keeping the moderate space-charge detuning. The advantage of the second harmonic MR RF cavity, including the estimation of the beam losses during the injection and acceleration processes, is discussed.
NSRRC, Hsinchu
Taiwan Photon Source (TPS) is a new third generation synchrotron storage ring which will be built at the present site of the NSRRC. Collective effects in the TPS storage ring have been simulated with tracking code ELEGANT. Quasi-Green's function for the entire ring and coherent synchrotron radiation (CSR) have been taken into account in the simulations. Thresholds of the longitudinal microwave instability and the CSR induced instability have been estimated. Time-dependent sawtooth oscillations of the bunch length at high bunch currents have been analyzed and compared to the bunch length oscillations observed at the SLC damping ring.
KEK, Ibaraki
KEKB is an e-/e+ collider for the study of B physics and is also used for machine studies for future machines. The peak luminosity of KEKB, which is the world-highest value, has been still increasing. This report summarizes recent progress at KEKB.
GSI, Darmstadt
CERN, Geneva
The measurement of synchrotron nonlinear components is an essential step for devising an effective compensation scheme for improving machine performances. A validation test of a recently proposed method called nonlinear tune response matrix (NTRM) for measuring circular accelerator nonlinear components is undergoing in a CERN-GSI joint effort. The test consists in the attempt of reconstructing few controlled octupolar components in the SPS synchrotron. In this proceeding we report on the SPS benchmarking experiment and discuss the performances the NTRM method applied to this measurements.
ISA, Aarhus
At Aarhus University in Denmark, a new synchrotron radiation source is being built. The 46-m circumference storage ring with 6-fold symmetry will operate at 580 MeV to produce bright UV and soft x-ray radiation. The storage ring will have a horizontal emittance of around 10 nm. Four straight sections will be available for insertion devices including a 12-pole wiggler with a field of 2 Tesla. ASTRID2 will operate in top-up mode with electrons from the present storage ring ASTRID, used as a booster. The insertion devices will have a strong influence on the lattice, and studies of dynamical aperture and compensation of tunes and beta beat will be presented. Also injection simulations will be given. The technical layout with details about magnetic arrangements on girders will be shown, including the vacuum system with extensive use of NEG. A 105 MHz RF system is being built together with a new LLRF system. At present, most major components have been ordered, and first injection will take place in the first half of 2011.
SOLEIL, Gif-sur-Yvette
SOLEIL is the French 2.75 GeV high brilliance third generation synchrotron light source delivering photons to 20 beamlines with a current of 400 mA in multibunch or hybrid modes, and 60 mA in 8 bunch mode. There are already 17 insertion devices installed and 9 others are planned in the next 2 coming years. Among them, two canted in vacuum insertion devices are planned, for the Nanoscopium and Tomography beamlines, and will be accommodated in a 12 m long straight section, with a 6.5 mrad separation angle. These ~150 m long beamlines will exploit the high brilliance and coherence characteristics of the X-ray (5-20 keV) beam both for diffraction limited focusing and for contrast formation. To provide low vertical beta functions at each undulator, an extra triplet of quadrupoles was added in the middle of the section. We present here the lattice implementation footprint, the different working point under investigations as well as the first results of the measurements on the machine performances.
DESY, Hamburg
JAI, Oxford
PETRA III is a 3rd generation synchrotron radiation light source which started commissioning in April 2009. Turn-by-turn capabilities are available for all 227 BPMs installed in the storage ring thus providing a powerful diagnostic tool for the characterization of the linear and nonlinear motion of the stored beam. We report on first results of beam dynamics studies using multiturn data acquired at PETRA III and first steps towards a calibration of the linear and nonlinear lattice model of the storage ring.
JASRI/SPring-8, Hyogo-ken
The SPring-8 storage ring has been operated for more than ten years and provided brilliant hard X-ray radiation to users. In recent years there are some discussions on upgrade plans of existing synchrotron radiation facilities and proposals of new facilities. In these the target brilliance of photons is set to be comparable or even higher, in some energy range, than that of the present value of SPring-8. At SPring-8 a design study of a new storage ring is now in progress for the future upgrade plan. The lattice structure will be changed from the present double-bend type to the multi-bend one, keeping the source position of all insertion devices unchanged. The emittance will be lowered from the present value of 3.4nmrad at 8GeV to 0.4nmrad at 6GeV (or 0.8nmrad at 8GeV) in the case of triple-bend lattice and 0.2nmrad at 6GeV (or 0.3nmrad at 8GeV) in the case of quadruple-bend lattice. We will report the present state of our preliminary work on lattice design. Nonlinear resonance correction to enlarge the dynamic aperture for on- and off-momentum electrons will also be discussed.
PAL, Pohang, Kyungbuk
POSTECH, Pohang, Kyungbuk
The PAL (Pohang Accelerator Laboratory) has been carrying out the performance upgrade project, PLS-II. The lattice of the storage ring for PLS-II was changed in whole. The energy was increase from 2.5GeV to 3.0GeV thus many magnets installed in storage ring at present should be replaced with new one or modified. The field of the quadrupole and sextupole magnets will be measured using the rotating coils that are newly fabricated with the engineering ceramic for the first time at PAL. The data acquisition system for the field measurement was also rebuilt to make it simple and to have a good signal to noise ratio. In this presentation, the design parameters of the ceramic rotating coil are described. And various characteristics of the field measurement system are also presented
MAX-lab, Lund
In 2009 the MAX IV facility was granted funding by Swedish authorities. Construction of the facility will begin this summer and user operation is expected by 2015. MAX IV will consist of a 3.4 GeV linac as a driver for a short-pulse radiation facility (with planned upgrade to a seeded/cascaded FEL) as well as an injector for two storage rings at different energies serving user communities in separate spectral ranges. Thanks to a novel compact multibend-achromat design, the 3 GeV ring will deliver a 500 mA electron beam with a horizontal emittance below 0.3 nm rad to x-ray insertion devices located in 19 dispersion-free 5 m straight sections. When the 3 GeV ring goes into operation in 2015 it is expected to become the highest electron-brightness storage ring light source worldwide. The 1.5 GeV ring will serve as a replacement for both present-day MAX II and MAX III storage rings. Its below 6 nm rad horizontal emittance electron beam will be delivered to infrared and UV insertion devices in twelve 3.5 m straight sections. We report on design progress for the two new storage rings of the MAX IV facility.
LBNL, Berkeley, California
MIT, Cambridge, Massachusetts
We have developed computer models for a pulsed-multipole magnet injection scheme for the Advanced Light Source (ALS) at Lawrence Berkeley National Lab. The multipole kicker injection scheme is further shown to be com- patible with the ALS in combination with a magnet lattice that has a low beta-function in the injection straight. Since traditional injection schemes are not compatible with such optimized low beta lattices, implementing the new injection scheme opens up several new possibilities. For instance, the adoption of a low beta lattice can greatly increase brightness due to the better matching of photon and electron beam emittances. This document explains the principles of the injection and the simulations we performed to show that the concept is sound.
LBNL, Berkeley, California
The Advanced Light Source is one of the earliest 3rd generation light sources. With an active upgrade program it has remained competitive over the years. The latest in a series of upgrades is a lattice upgrade project that was started in 2009. When it will be completed, the ALS will operate with a horizontal emittance of 2.2 nm and an effective emittance of 2.6 nm. Combined with the high current of 500 mA and the small vertical emittance the ALS already operates at this upgrade will keep it competitive for years to come. The presentation will present the status of the upgrade, including beam dynamics studies and lattice optimizations as well as the magnet design and status.
Cornell University, Ithaca, New York
CLASSE, Ithaca, New York
The proposed Cornell Energy Recovery Linac (ERL) is designed for bunches of 77pC and 100mA whose energy is recovered. However, the ERL linac can also be used for larger bunch charges of reduced average current whose energy does not have to be recovered. The proposed Cornell ERL lightsource currently uses a split linac arrangement connected by a turnaround arc. In order to avoid the detrimental effects of Coherent Synchrotron Radiation (CSR) in this arc, a high charge (1nC) bunch must remain relatively long (2ps), and be compressed at high energy (5GeV). An appropriate bunch compressor must take second order effects into account, which adds complications for the large energy spread associated with compression to 100fs or less. We have therefore designed a very simple four dipole bunch compressor at high energy, which uses second order time of flight terms in the turnaround arc rather than in the bunch compressor itself. This design is tested using particle tracking simulations incorporating CSR, as well as magnetic field errors and misalignments.
SLAC, Menlo Park, California
Design of PEP-X high brightness light source machine is under development at SLAC. The PEP-X is a proposed replacement of the PEP-II in the existing 2.2 km tunnel. Two of the PEP-X six arcs contain DBA type lattice providing 30 dispersion free straights suitable for 3.5 m long undulators. The lattice contains TME cells in the other four arcs and a 90 m wiggler in a long straight section yielding an ultra low horizontal emittance of ~0.1 nm-rad at 4.5 GeV for a high brightness. The recent lattice modifications further increase the predicted brightness and improve beam dynamic properties. The standard DBA cells are modified into supercells for providing low beta undulator straights. The DBA and TME lattice parameters are better optimized. Harmonic sextupoles are added into the DBA arcs to minimize the sextupole driven resonance effects and amplitude dependent tune shift. Finally, the injection scheme is changed from vertical to horizontal plane in order to avoid large vertical amplitudes of injected beam within small vertical aperture of undulators.
BNL, Upton, Long Island, New York
Chromaticity is usually set to non-zero value at the third generation light sources to cure the intensity induced instabilities. It is effective in suppressing the beam centroid oscillation; however, it is repeatedly reported that the beam lifetime decreases significantly when chromaticity goes up. This is probably due to the crossing of resonance lines by the enlarged tune footprint. In this paper we optimize the NSLS-II lattice at different positive chromaticity settings. The tune footprint is adjusted to fit in the stable region divided by the strong resonance lines. Tracking results show that we can maintain a lifetime similar to that of the zero-chromaticity lattice solutions.
BNL, Upton, Long Island, New York
NSLS-II is a third-generation light source that is being built at the Brookhaven National Laboratory. The storage ring has 30 double-bend-achromatic cells. Six 3.5-m-long damping wigglers (DW) will be installed in three straight section to lower the emittance. The civil construction of the facility started in June 2009 and major accelerator components, such as magnets and vacuum chambers, have entered production phase. This paper will summarize the physics considerations for the NSLS-II magnet specifications. In particular, we discuss the tuning range required by the lattice flexibility, and the issues which lead to the specification for the higher-order multipoles.
Melbourne
ASCo, Clayton, Victoria
The Australian Synchrotron storage ring has a resistive wall instability in the vertical plane. Presently this instability is being controlled by increasing the vertical chromaticity. However new in-vacuum insertion devices that significantly increase the ring impedance may demand chromatic corrections beyond the capabilities of the sextupole magnets. A transverse bunch-by-bunch feedback system has been commissioned to combat the vertical instability* and provide beam diagnostics**. A high frequency narrow band mode that could not be damped was initial encountered with IVUs at minimum gap preventing the system from being implemented during user beam. Tuning of the bunch fill pattern, the digital filters and mapping out the system response lead to a configuration for user mode operations.
* Spencer, M.J. et. al. EPAC'08, Genoa, Italy
** Peake, D.J. et. al. PAC'09, Vancouver, Cananda
LNLS, Campinas
"Green solutions" using permanent magnets are being proposed for the dipoles and quadrupoles of the second Brazilian Synchrotron Light Source - LNLS2 - magnetic lattice. The main purpose is to reduce as much as possible the electrical energy consumption, assuring the reliability of the magnets during several years. Sextupoles will have multiple functions due to the limited space in the lattice design.
CLS, Saskatoon, Saskatchewan
To investigate the effect of an elliptically polarized undulator (EPU) on the dynamic aperture of storage ring a model is required for use in an optics code. An EPU can be modelled as an array of skew dipole magnets. The skew angle ranges from zero to ninety degrees depending on the degree of polarization. Crudely the EPU can be modelled using alternating skew dipole blocks. A model that better reproduces the sinusoidally varying fields can be achieved by slicing blocks into smaller subsets. Field roll-off produced by the limited transverse dimensions of the magnet blocks can be included as skew multipoles. For example the roll-off of the horizontal field in the vertical undulator mode is very nearly a skew sextupole. The model has the advantage of correctly calculating the path length through the EPU which is important for tracking in six dimensions.
PAL, Pohang, Kyungbuk
Lattice of the Storage Ring (SR) is changed from TDB to DBA, and beam energy is enhanced from 2.5 GeV to 3.0 GeV at the Pohang Light Source upgrade (PLS-II). Therefore all magnet specification and number have to change compare with exist PLS SR. At the PLS-II, Magnet Power Supplies (MPS) must be re-designed according to magnet specification of the PLS-II. Newly development MPSs are adopted switching type power conversion technology. High current unipolar MPSs are parallel operation type of unit module buck type power supply, and low current bipolar MPSs are H-bridge type. All MPSs are performed ± 10 ppm output current stability and adopted full digital controller. In this paper, we report on the development and characteristics of the MPS for PLS-II SR.
CELLS-ALBA Synchrotron, Cerdanyola del Vallès
CITCEA-UPC, Barcelona
ALBA is a 3 GeV third generation synchrotron light source under construction in Spain. The design and performance of the ALBA Storage Ring Power Converters will be described. A total of 122 power converters are required: 1 for the dipoles (all connected in series), 112 for the quadrupoles (each magnets with its own power supply) and 9 for the sextupoles (each family connected in series). All converters are switched mode with full digital regulation and a common control interface. The paper will describe the performance of the power converters and compare it with the design specifications.
NSRRC, Hsinchu
The Taiwan Photon Source (TPS), a third-generation synchrotron radiation light source, should be installed with 1032 sets of magnet power supplies for the storage ring and 152 sets for the injector. All of the power supplies are preferred in PWM switched mode with IGBT or MOSFET. A high precision DC power supply for 48 dipoles of the storage ring; there are 240 quadrupole magnets and 168 sextupole magnets in storage ring, the main winding of quadrupole and 168 sextupole magnets are powered by individual power supplies. In the booster ring, one set of dynamic power supply for the dipole magnets and four sets for quadrupole magnets run at the biased 3Hz quasi sinusoidal wave. There are several hundred corrector (fast and slow) magnets and skew quadrupole magnets in storage ring and injector are powered by the same bipolar power converters.
ANL, Argonne
The DC/DC converters in the Advanced Photon Source storage ring are more than 15 years old, and an upgrade is underway to resolve the aging and obsolescence issues. In the upgrade, an 18-bit resolution for current regulation is desired. This paper describes a digital control system to achieve this goal. The system uses a serializer chip, TI TLK2541, combined with a ∑-Δ modulator to realize a 21-bit digital pulse width modulation (DPWM). Analog and digital filters are implemented to block the ripple currents and to reduce the EMI noises. Deployed with filter circuits, a digital compensator has been designed to meet the requirements of output current regulation. Furthermore, a voltage feed forward is employed to compensate for input bus voltage variations. A prototype digital controller using a field-programmable-gate-array development board has been developed. The resolution of the current regulation, and the effect of noises into the digital controlled power converter system have been tested and analyzed.
SLAC, Menlo Park, California
SLAC is developing a long-range plan to transfer the evolving scientific programs at SSRL from the SPEAR3 light source to a much higher performing photon source that would be housed in the 2.2-km PEP-II tunnel*,**. The proposed PEP-X storage ring is one of the possibilities. The goal of the PEP-X design is to develop an optimal light source design with horizontal emittance less than 100 pm at 4.5 GeV and vertical emittance of 8 pm corresponding to the diffraction limit of 1-Å X-ray. The low emittance design requires a lattice with strong focusing leading to high natural chromaticity and therefore to strong sextupoles. The latter cause reduction of dynamic aperture. The horizontal dynamic aperture required at PEP-X injection point is about 10 mm. In order to achieve the desired dynamic aperture, transverse non-linearities of PEP-X are studied. The program LEGO*** is used for particle tracking simulations. The technique of frequency map is used to analyze the nonlinear behavior. The effects of the non-linearities are tried to minimize. The details and results of dynamic aperture optimization are discussed in this paper.
*,** R. Hettel et al., 'IDEAS FOR A FUTURE PEP-X LIGHT SOURCE', EPAC08, 'CONCEPTS FOR THE PEP-X LIGHT SOURCE', PAC09.
*** Y. Cai et al., 'LEGO: A Modular accelerator design code', PAC97, 1997.
BNL, Upton, Long Island, New York
LAL, Orsay
IN2P3-LAPP, Annecy-le-Vieux
OXFORDphysics, Oxford, Oxon
CERN, Geneva
KEK, Ibaraki
SLAC, Menlo Park, California
The KEK ATF2 facility, with a well instrumented beam line and Final Focus (FF), is a proving ground for linear collider (LC) technology to demonstrate the extreme beam demagnification and spot stability needed for a LC FF*. ATF2 uses water cooled magnets but the baseline ILC calls for a superconducting FF**. Thus we plan to replace some ATF2 FF magnets with superconducting ones made via direct wind construction as planned for the ILC. With no cryogenic supply at ATF2, we look to cool magnets and current leads with a few cryocoolers. ATF2 FF coil winding is underway at BNL and production warm magnetic measurements indicate good field quality. Having FF magnets with larger aperture and better field quality than present FF might allow reducing the beta function at the FF for study of focusing regimes relevant to CLIC. Our ATF2 magnet cryostat will have laser view ports for cold mass movement measurement and FF support and stabilization requirements under study. We plan to make stability measurements at BNL and KEK to relate ATF2 FF magnet performance to that of a full length ILC R&D prototype at BNL. We want to be able to predict LC FF performance with confidence.
* ATF2 proposal, volumes 1 and 2 at http://lcdev.kek.jp/ILC-AsiaWG/WG4notes/atf2/proposal/index.html
** International Linear Collider Reference Design Report, ILC-REPORT-2007-001, August 2007.
ODU, Norfolk, Virginia
JLAB, Newport News, Virginia
BNL, Upton, Long Island, New York
Recirculating linear accelerators (RLA) are the most likely means to achieve the rapid acceleration of short-lived muons to multi-GeV energies required for Neutrino Factories and TeV energies required for Muon Colliders. In the work described here, a novel arc optics based on a Non Scaling Fixed Field Alternating Gradient (NS-FFAG) lattice is developed, which would provide sufficient momentum acceptance to allow multiple passes (two or more consecutive energies) to be transported in one string of magnets. We present a combination of the non-scaling NS-FFAG RLA placed in a straight section. Orbit offsets of different energy muons are kept small in the NS-FFAG arcs during multiple passes. The NS-FFAG, made of densely packed FODO cells, allows momentum acceptance of dp/p=±60%. This solution would reduce overall cost and simplify the operation. Difference in a muon path length for corresponding energies is corrected with a chicane. We will also discuss technical requirements to allow the maximum number of passes by using an adjustable path length to accurately control the returned beam phase to synchronize with the RF.
INFN/LNF, Frascati (Roma)
To achieve luminosities significantly higher than in existing machines, future storage-ring based colliders will need to operate in novel parameter regimes combining ultra-low emittance, large Piwinski angle and high bunch charge; implementation of techniques such as a "crab waist" will add further challenges. Understanding the beam-beam interaction in these situations will be essential for the design of future very high luminosity colliders. Recent developments in modeling tools for studying beam-beam effects, capable of investigating the relevant regimes, will be discussed and examples, including tests with crab waist collisions in DAΦNE, will be presented.
GSI, Darmstadt
ITEP, Moscow
The heavy ion synchrotron SIS-100 will play a key role within the future FAIR project underway at GSI. Although this synchrotron is optimized for fast extraction, also slow extraction will be used. Slow extraction is based on beam excitation due to a third order resonance. The spread in the particle momenta generating a tune spread causes particle loss leading to an irradiation of the machine especially in a high-current operation. A major part of the losses is assumed to occur at the electro-static separator. In the present study we apply a tracking method to model the extraction process to predict the losses, where, in a first step, high current effects are not taken into account.
GSI, Darmstadt
IAP, Frankfurt am Main
With the ability to accelerate heavy ions up to an energy of 32 GeV/u, the SIS300 superconducting (sc) synchrotron is a central part of the new FAIR facility at GSI-Darmstadt. SIS300 will provide beams with a 20-fold increase in energy and, by means of a stretcher mode or a fast ramped mode (1 T/s), 100-10000 times higher average intensity. The beam from SIS300 will be extracted towards the experiments using resonant slow extraction, thus SIS300 becomes the first superconducting synchrotron worldwide with this feature. Coupling and persistent currents are the main practical limitation for operation of sc magnets at high ramping rates and long slow extraction plateaus. The effect of the persistent currents, which are time dependent and depend as well on the magnet's history, is especially critical for slow extraction at low energies. These effects determine the tolerances on magnetic components. In order to address this issue, detailed simulations of beam dynamics at slow extraction have been performed. In particular, the optimization of the lattice and its optical parameters for a low-loss extraction in the presence of steady and time-dependent field components will be presented.
JAEA/TARRI, Gunma-ken
To achieve ultra-low-fluence large-area uniform irradiation of ion beams for advanced applications in the field of materials sciences and biotechnology, a uniform-beam irradiation system has been developed using multipole magnets at the Japan Atomic Energy Agency (JAEA) cyclotron facility. The system consists of a beam attenuator for the wide-range intensity control, an electrostatic beam chopper for the control of irradiation time, scattering foils for conditioning of the initial beam distribution, octupole magnets for transverse tail-folding, sextupole magnets for the correction of the beam misalignment, and the diagnostic station of the two-dimensional beam profile. In this paper, recent experimental results are described, especially on the formation of a beam with a uniform transverse distribution by the combination of the sextupole and octupole magnets.
RIKEN Nishina Center, Wako
The superconducting ECR ion source enabled to use a 28 GHz microwave source had been developed to provide intense beam of highly charged heavy ions like U35+ to the RIKEN RI-beam factory (RIBF) since 2007. The first plasma was lit in May of 2009 and it was succeeded in providing the uranium beam to the RIBF in December. In this operation, uranium ions were supplied with sputter method and two 18 GHz microwave sources were used. The beam intensity of the uranium ion exceeded 14μAmps, which was more than five times larger than that for 18 GHz ECR ion source of a usual type. The extraction system consists of the accel-decel electrode system, a solenoid coil and a 90 degreeanalyzing magnet. We measured the profiles and emittances of the extracted beams for several ion species and compared with the calculated results with 'OPERA-3d' including space charge effect. And we shall discuss the beam dynamics at the extraction region such as the relationship between the beam emittance and the operating parameters.
CEA, Gif-sur-Yvette
GANIL, Caen
ANL, Argonne
S3 (Super Separator Spectrometer) [1] is a future device designed for experiments with the high intensity heavy ion stable beams of SPIRAL2 [2] at GANIL (Caen, France). It will include a target resistant to these very high intensities, a first stage momentum achromat for primary beam extraction and suppression, a second stage mass spectrometer and a dedicated detection system. This spectrometer includes large aperture quadrupole triplets with embedded multipolar corrections. To enable the primary beam extraction one triplet has to be opened on one side, which requires an appropriate design of such a multipolar magnet. The final mass separation power required for S3 needs a careful design of the optics with a high level of aberration correction. Multiple symmetric lattices were studied for this purpose. A 4-fold symmetric lattice and the achieved results are described in this paper.
[1] A. Drouart et al., Nucl. Phys. A 834 (2010) 747c. [2] SPIRAL2, http://pro.ganil-spiral2.eu/spiral2
DESY, Hamburg
An achromat is a focusing system, in which as large a number of higher order aberrations as possible is canceled by symmetries of the linear optics and the rest is corrected by the usage of third and higher order multipoles. The first achromats ever considered were repetitive achromats, in which the cancellation of higher order aberrations relies on appropriate selection of cell tunes. Later on achromats, employing mirror symmetry, were also developed. In this paper we remove one superfluous constraint on the linear optics in the theory of four cell mirror symmetric achromats, make an accurate consideration of two cell repetitive achromats, and compare the number of multipoles required for each of those achromats. Moreover, we contribute a point of view, from which both approaches to the achromat design become identical. As a practical application we consider the design of the arcs of the post-linac collimation section of the European XFEL Facility.
JASRI/SPring-8, Hyogo-ken
A set of three in-vacuum undulators is going to be installed in one of four long straight sections of the SPring-8 storage ring. In order to make the undulator gap as narrow as possible, we plan to divide this long straight section into three sub-sections and install quadrupole magnets between these sub-sections to lower the vertical betatron function. In the modified lattice, however, the symmetry of the ring is lowered and in general it becomes difficult to keep a sufficient dynamic aperture for on- and off-momentum electrons. The long straight sections were originally introduced in the year 2000 and at that time we developed a method of "quasi-transparent matching of sextupole fields" where two key concepts of betatron phase matching and local chromaticity correction were combined to obtain a sufficient dynamic aperture and momentum acceptance. Then, in the year 2007 "counter-sextupole magnets" were further installed to cancel the effect due to non-linear kick by sextupole magnets used for local chromaticity correction. In designing the new lattice with a modified long straight section, we followed the same line and could recover the dynamic aperture and momentum acceptance.
Kyungpook National University, Daegu
Proton Engineering Frontier Project (PEFP) Linac has a plan of the addition of 1 GeV RCS ring. The lattice of the rapid cycling synchrotron is affected by a non-linear beam dynamics. In this study, we investigated about non-linear dynamics due to sextupoles in PEFP RCS. Notably, we investigated about 3rd integer resonance due to sextupoles. To slowly and continuously extract the proton beam, we utilize the 3rd integer resonance. For the reason, we investigated non linear beam dynamics due to 3rd integer resonance and slow extraction system by using of MAD8.
CERN, Geneva
The main guidelines of the LHC insertion (IR) upgrade Phase I are 1) the development of wider aperture (120 mm) and lower gradient (~120 T/m) quadrupoles using the well-characterized Nb-Ti technology in order to replace the existing inner triplets (IT) equipping the ATLAS and CMS high-luminosity IRs of the LHC, 2) while maximizing the use of the current LHC infrastructure, in particular leaving unchanged the so-called "matching sections" (MS) and "dispersion suppressors" (DS) of these two insertions. One of the initial goals was to be able to squeeze the optics up to a beta* of 25 cm. However, optics solutions with a beta* of 30 cm seems already to be at edge of achievability, both in terms of the IT and MS mechanical acceptance, gradients of the MS and DS quadrupole magnets, and correctability by the LHC arc sextupoles of the huge chromatic aberrations induced by the new inner triplet at ultimate beta*. The layout of the new inner triplet and the corresponding injection and collision optics will be presented and analyzed both in terms of aperture, squeeze-ability and chromatic correction.
CERN, Geneva
This paper describes a detailed analysis of various non-linear effects of the nominal Negative Momentum Compaction lattice for PS2. Chromaticity and orbit correction schemes together with dynamic aperture studies are presented. The impact of magnet errors is being assessed and tolerances are evaluated. Frequency and diffusion maps are produced and, combined with non-linear driving terms analysis, are used for working point optimization.
CERN, Geneva
BNL, Upton, Long Island, New York
Consolidation of the coupling correction scheme in the LHC is motivated due to a missing skew quadrupole family in Sector 3-4 at the start-up in 2009. Simultaneous coupling and vertical dispersion correction using vertical orbit bumps at the sextupoles, was studied by analyzing turn-by-turn data. This scheme was tested in SPS where the optical structure of arc cells is quite similar to the LHC. In SPS, horizontal and vertical beam positions are measured separately with single plane BPMs, thus a technique to construct "pseudo double plane BPM" is also discussed.
Cockcroft Institute, Warrington, Cheshire
The University of Liverpool, Liverpool
One of the major challenges for the International Linear Collider (ILC) damping rings is the attainment of the 2 pm vertical emittance specification. To achieve such an ultra-low vertical emittance a highly effective diagnostics and correction system is needed. However, since both BPMs and correctors have also negative impacts on the design (cost, complexity, impedance), it is important to understand how the number and locations of both these components affect the correction. In this paper we present the results of simulations for the Technical Design Phase baseline damping rings lattice (DCO4), aimed at understanding the effectiveness of orbit, dispersion, and coupling correction for different design and operation scenarios.
CLASSE, Ithaca, New York
We are developing techniques for measuring and correcting emittance diluting optical and alignment errors in the CesrTA storage ring. Our principle measurement method is to resonantly excite the beam at all three normal mode frequencies and then to extract the amplitude and phase of each mode at all 100 beam position monitors. We reconstruct beta-functions, betatron phase advance, coupling parameters, dispersion, and BPM tilts from the data. A complete characterization including data collection and analysis can be done in a few minutes. To measure the emittance, an x-ray beam size monitor capable of measuring the size of a single bunch on a turn by turn basis provides a real time measure with a resolution on the order of a few microns. This resolution corresponds to a few pm emittance. Our ability to identify alignment and optical errors is limited by systematic measurement errors. We report on the status of our efforts to understand and eliminate systematic errors, the accuracy of our characterization of the machine optics, and our success at reducing sources of emittance dilution.
SLAC, Menlo Park, California
We use measured or simulated magnetic fields for dipoles and quadrupoles to build a lattice model for SPEAR3. In a non-symplectic approach the phase space coordinate mapping on the fields is based on Runge-Kutta integration of the equation of motion. In a symplectic approach we approximate the fields with proper fringe field models. Complication of the use of rectangular gradient dipoles in SPEAR3 is considered. Results of the model is compared to measurements on the real machine.
DESY, Hamburg
We consider a beam line, in which pure betatron oscillations are transversely uncoupled, but which has nonzero horizontal and vertical dispersions simultaneously. We show that transverse oscillations in such a beam line could be chromatically coupled if the horizontal dispersion is nonzero in the vertical bending magnets and vice versa. We also show that the ability of sextupoles to generate chromatic coupling terms depends on the relation between sextupole tilt angles and the direction of the dispersion vector at the sextupole locations. We discuss different approaches to the setup of sextupole tilt angles depending on chromatic aberrations taken for correction. As a practical application we consider the usage of tilted sextupoles in the design of the beam switchyard at the European XFEL Facility.
JASRI/SPring-8, Hyogo-ken
The dynamic aperture is of importance for high injection efficiency and long lifetime of a storage ring. At the SPring-8 storage ring, a third generation light source facility, various improvements of the dynamic aperture were developed, e.g. the introduction of supplemental sextupole magnets at long straight sections, and the symmetry restoration of linear lattice. To understand the nonlinear dynamics limiting the aperture, the measurements were performed for the various operation conditions with the improvements. Using injection bump magnets and turn-by-turn beam position monitor system, we measured the horizontal dynamic aperture. The Fourier analysis of the oscillation of the kicked beam shows the resonance excitation influential on the dynamic aperture. The knowledge through the experiments is essential to the further improvements of the dynamic aperture of the present ring and the new storage ring design of the future SPring-8 upgrades.
CELLS-ALBA Synchrotron, Cerdanyola del Vallès
The high order magnetic multipole components of all the magnets in the ALBA storage ring have been measured. Previous studies have simulated the effects of the HOMs using statistic methods. The magnets have been installed now in the tunnel, allowing for a better simulation of the future impact of the HOMs in the performance of the light source. In this paper, the effect of the high order multipoles of the dipole, quadrupole and sextupole magnets in the dynamic aperture and the Touschek lifetime are reviewed.
Diamond, Oxfordshire
Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin
JAI, Oxford
CERN, Geneva
The correct implementation of the nonlinear ring model is crucial to achieve the top performance of a synchrotron light source. Several dynamics quantities can be used to compare the real machine with the model and eventually to correct the accelerator. Most of these methods are based on the analysis of turn-by-turn data of excited betatron oscillations. We present the experimental results of the campaign of measurements carried out at the Diamond. A combination of Frequency Map Analysis and resonant driving terms measurements has allowed a precise calibration of the nonlinear model capable of reproducing and then correcting the nonlinear beam dynamics in the storage ring.
ANL, Argonne
APS linear model is defined by the quadrupole and skew quadrupole errors that are determined using the response matrix fit. What was missing until now were the sextupole offsets relative to the beam orbit. At APS the orbit is routinely steered according to user requests, and at some locations the steering has accumulated to rather large values. That is why the usual sextupole changes that are performed during operation mode switches lead to optics and coupling changes. Knowledge of the sextupole offsets would allow us to predict and control those changes. There are a number of ways to measure sextupole offsets but most of them utilize element by element approach. This would take very long time for the 280 sextupoles at APS. Here we describe a method that determines the beam offsets of all sextupoles based on fitted values of local optics and coupling changes at each sextupole. We perform response matrix measurement, fit several lattices with different sextupoles, and derive the sextupole offsets. The results are included in the linear model of the APS storage ring.
LBNL, Berkeley, California
Frequency Map Analysis has been used successfully to study accelerator lattices for many years, both in simulations and in experiment. We will present a new application to use the quantitative results of frequency maps (namely the diffusion rates) to optimize the nonlinear properties of lattices. The technique is fairly simple but powerful and has already been used to optimize lattices for example for the NLC and ILC damping rings, as well as the ALS lattice upgrade.
BNL, Upton, Long Island, New York
SBU, Stony Brook, New York
The RHIC beam lifetime in polarized proton operation is dominated by the beam-beam effect, parameter modulations, and nonlinear magnet errors in the interaction region magnets. Sextupole and skew sextupole errors have been corrected deterministically for a number of years based on tune shift measurements with orbit bumps in the triplets. During the most recent polarized proton run 10- and 12-pole correctors were set through an iterative procedure, and used for the first time operationally in one of the beams. We report on the procedure to set these high-order multipole correctors and estimate their effect on the integrated luminosity.
BNL, Upton, Long Island, New York
In this article, based on the contributions of the chromatic sextupole families to the half-integer resonance driving terms, we discuss how to sort the chromatic sextupoles in the arcs of the Relativistic Heavy Ion Collider (RHIC) to easily and effectively correct the second order chromaticities. We propose an online method with 4 knobs or 4 pairs of chromatic sextupole families to correct second order chromaticities. Numerical simulations support this method and shows that it improves the balance of correction strengths among the sextupole families and avoids reversal of sextupole polarities, as well as yielding larger dynamic apertures for the 2009 RHIC 100 GeV polarized proton run.