BNL, Upton, Long Island, New York
Funding: Work supported by U.S. DOE, Contract No.DE-AC02-98CH10886
The NSLS-II light source is a proposed 3 GeV storage ring, with the potential for ultra-low emittance*. Despite the reduced emittance goal for the bare lattice, the closed orbit amplification factors are on average >50 in both planes, for random quadrupole alignment errors. The high chromaticity will also require strong sextupoles and the low 3 GeV energy will require large dynamic and momentum aperture to insure adequate lifetime. This will require tight alignment tolerances (~30microns) on the multipole magnets during installation. By specifying tight alignment tolerances of the magnets on the support girders, the random alignment tolerances of the girders in the tunnel can be significantly relaxed. Using beam based alignment to find the golden orbit through the quadrupole centers, the closed orbit offsets in the multipole magnets will then be reduced to essentially the alignment errors of the magnets, restoring much of the DA and lifetime of the bare lattice. Our R&D program to achieve these tight alignment tolerances of the magnets on the girders using a vibrating wire technique**, will be discussed and initial results presented.
*Work presented on behalf of the NSLS-II Design Team, CDR(2006) and CD2(2007).
**A. Jain, et al, International Workshop on Accelerator Alignment, Tsukuba, Japan, Feb.11-15, 2008.
BINP SB RAS, Novosibirsk
CELLS-ALBA Synchrotron, Cerdanyola del Vallès
BINP has manufactured and measured 243 multipoles of 9 types for the ALBA storage ring. The magnets had severe requirements on the manufacturing tolerances and the alignment of their magnetic axes. The quadrupole magnets are made of 1mm laminated yokes with the bore diameter of 61mm. The sextupole magnets are made of 0.5mm laminated yokes with the bore diameter of 76mm. Rotating coils and Hall probes have been used for the magnetic measurements. The features of manufacturing and magnetic measurements are presented in this paper.
HUST, Wuhan
Funding: National Natural Science Foundation of China (No. 10435030)
A 10MeV H- compact cyclotron (CYCHU-10) is under construction in Huazhong University of Science and Technology (HUST). This paper presents a magnetic field measurement system for measuring the cyclotron magnet. A Hall probe and a granite x-y stage are adopted in the project. The Cartesian mapping will replace traditional polar system. The motion control and data acquisition system for the magnetic field measurement consists of a Teslameter and Hall probe, servomotors, a motion control card, optical linear encoder systems and an industrial PC. The magnetic field will be automatically scanned by this apparatus, and a flying mode will be the main running mode to reduce measure time.
Fermilab, Batavia
Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-07CH11359
An R&D proton linac is under construction at FNAL and it will use solenoid lenses in the beam transport line. Because the needed focusing field is on the level of 6 Tesla, superconducting systems are used. In the low energy part of the linac, which uses room temperature accelerating structures, the lenses are placed in stand-alone cryostats. Production of the lenses and cryostats for the low energy section is under way. In the superconducting accelerating sections, the lenses are mounted inside RF cryomodules. Although focusing solenoids for the high energy sections have been designed and prototypes tested, R&D is still ongoing to address magnetic shielding and alignment issues. This report summarizes the performance of lenses for the low-energy part of the linac and presents the status of ongoing R&D.
LBNL, Berkeley, California
Fermilab, Batavia
BNL, Upton, Long Island, New York
Funding: This work was supported in part by the Director, Office of Science, High Energy Physics, U.S. Department of Energy under contract No. DE-AC02-05CH11231
Pushing accelerator magnets beyond 10 T holds a promise of future upgrades to machines like the Large Hadron Collider (LHC) at CERN. Nb3Sn conductor is at the present time the only practical superconductor capable of generating fields beyond 10 T. In support of the LHC Phase-II upgrade, the US LHC Accelerator Research Program (LARP) is developing a large bore (120mm) IR quadrupole (HQ) capable of reaching 15 T at its conductor peak field. The 1 m long two-layer coil, based on the design of the LARP TQ quadrupole series that achieved 230 T/m in a 90 mm bore, will demonstrate additional features such as alignment and accelerator field quality while exploring the magnet performance limits in terms of gradient, forces and stresses. In this paper we summarize the design and report on the magnet construction progress.
SLAC, Menlo Park, California
The LCLS project at SLAC requires 40 undulators be tuned, fiducialized, and a final data set taken. The techniques used to do this work are presented. In addition, the quadrupoles between the undulators must be accurately fiducialized. A description of the quadrupole magnetic measurements and fiducialization is also presented.
CERN, Geneva
The LHC collider has recently started-up at CERN. It will provide colliding beams to four experiments installed in large underground caverns. A specially designed and constructed sector of the LHC beam vacuum system transports the beams though each of these collision regions, forming a primary interface between machine and experiment. ATLAS is the largest of the four LHC colliding beam experiments, being some 40 m long and 22 m in diameter. Physics performance, geometry and access imposed a large number of constraints on the design of the beam vacuum system. This paper describes the geometry and layout of the ATLAS beam vacuum system. Specific technologies developed for ATLAS, and for the alignment and installation of the vacuum chambers are described as well as the issues related to the physical interfaces with the experiment.
LANL, Los Alamos, New Mexico
LBNL, Berkeley, California
SAIC, Los Alamos, New Mexico
Funding: National Nuclear Security Administration of the US Department of Energy
The Dual-Axis Radiographic Hydrodynamic Test Facility (DARHT) at Los Alamos National Laboratory (LANL) consists of two linear induction accelerators oriented at right angles to each other. The DARHT First Axis has been successfully operated since 1999 and produces a 60 ns pulse with beam energy of 20 MeV and beam current of 1.9 kA. The DARHT Second Axis was successfully commissioned in May 2008 and produces a 1600 ns pulse with beam energy of 17.5 MeV and beam current of 2.1 kA. The Second Axis Injector uses a 16.5 cm diameter thermionic cathode with a 10 A/cm2 required current density to emit electrons into the accelerator. During the early Second Axis commissioning activities in 2006, deficiencies in the DARHT Second Axis Injector were found that prevented the injector cathode from meeting the required 10 A/cm2 current density. A comprehensive campaign was initiated to solve the injector cathode performance issues. This paper describes the deficiencies found and the solutions used to enable the DARHT Second Axis Injector to meet its requirements.
SLAC, Menlo Park, California
ANL, Argonne
Funding: Work supported by U.S. Department of Energy under Contract Nos. DE-AC02-06CH11357 and DE-AC02-76SF00515.
We present the performance of the cavity beam position monitor (BPM) system for the LCLS undulator. The construction and installation phase of 34 BPMs for the undulator and 2 for the transport line have been completed. The X-band cavity BPM employs a TM010 monopole reference cavity and a TM110 dipole cavity designed to operate at a center frequency of 11.384 GHz. The signal processing electronics features a low-noise single-stage three-channel heterodyne receiver that has selectable gain and a phase locking local oscillator. The approximately 40 MHz IF is digitized by a 120M sample/second four-channel 16-bit digitizer. System requirements include sub-micron position resolution for a single-bunch beam charge of 200 pC. We discuss the system specifications and commissioning results.
RadiaBeam, Marina del Rey
Purdue University, West Lafayette, Indiana
UCLA, Los Angeles, California
Funding: This work is supported by the US Defense Threat Reduction Agency SBIR contract HDTRA1-08-P-0035.
Conventional X-ray sources used for medical and industrial imaging suffer from low spectral brightness, a factor which severely limits the image quality that can be obtained. X-ray sources based on Inverse Compton Scattering (ICS) hold promise to greatly improve the brightness of X-ray sources. While ICS sources have previously been demonstrated, and have produced high-peak brightness X-rays, so far experiments have produced low average flux, which limits their use for certain important commercial applications (e.g. medical imaging). RadiaBeam Technologies is currently developing a high peak- and average-brightness ICS source, which implements a number of improvements to increase the interaction repetition rate, as well as the efficiency and stability of the ICS interaction itself. In this paper, we will describe these improvements, as well as plans for future experiments.
JLAB, Newport News, Virginia
PKU/IHIP, Beijing
Funding: DOE Contract DE-AC05-060R23177; China Scholarship Council
This paper introduces a single lens laser beam shaper which is capable of redistributing a beam with a Gaussian profile to a super-Gaussian profile. Both geometrical and diffractive optical modelings are performed on a typical single lens shaper that shows significant reduction of destructive effects on the beam uniformity over those with sharp-edges.
Fermilab, Batavia
Funding: Operated by Fermi Research Alliance, LLC, under Contract No. DE-AC02- 07CH11359 with the U.S. Department of Energy.
In an exchange of technology agreement, Fermilab has built and delivered a 3.9 GHz (3rd harmonic) cryomodule to Deutsches Elektron-Synchrotron (DESY) Laboratory to be installed in the TTF/FLASH beamline. Transport to Hamburg, Germany was completed via a combination of flatbed air ride truck and commercial aircraft, while minimizing transition or handling points. Initially, destructive testing of fragile components, transport and corresponding alignment stability studies were performed in order to assess the risk associated with transatlantic travel of a fully assembled cryomodule. Data logged tri-axial acceleration results of the transport with a comparison to the transport study predicted values are presented.
CERN, Geneva
The Large Hadron Collider (LHC) has been aligned using classical and non-standard techniques. The results have been seen on September 10th, 2008, the day when the beam made several turns in the machine with very few correctors activated. The paper will present the different steps of the alignment, from the metrological measurements done during the phase of the magnets assembly to the alignment itself in the tunnel as well as the techniques used to obtain the accuracy required by the physicists. The correlation of the results of this alignment with the position of the beam seen on the BPMs by the operation team during the days the beam has circulated will be presented.
SLAC, Menlo Park, California
CERN, Geneva
Funding: Work supported through SLAC/DOE Contract DE-AC02-76-SF00515 and US LARP CERN collaboration.
The LHC Low Level RF System (LLRF) is a complex multi-VME crate system which is used to regulate the superconductive cavity gap voltage as well as to lower the impedance as seen by the beam through low latency feedback. This system contains multiple loops with several parameters which must be set before the loops can be closed. In this paper, we present a suite of matlab based tools developed to perform the preliminary alignment of the RF stations and the beginnings of the closed loop model based alignment routines. We briefly introduce the RF system and in particular the base band (time domain noised based) network analyzer system built into the LHC LLRF. The main focus of this paper is the methodology of the algorithms used in the routines within the context of the overall system. Measured results are presented which validate the technique. Because the RF systems are located underground in a location which is relatively un-accessible even without beam and completely un-accessible when beam is present, these tools will allow CERN LLRF experts to maintain and tune their LLRF systems from a remote location similar to what was done very successfully in PEP-II at SLAC.
ANL, Argonne
Funding: Work at Argonne was supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No DE-AC02-06CH11357.
The Linac Coherent Light Source (LCLS), now being commissioned at the Stanford Linear Accelerator Center (SLAC) in California, and coming online for users in the very near future, will be the world’s first x-ray free-electron laser user facility. Design and production of the undulator system was the responsibility of a team from the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). A sophisticated, five-axis, computer-controlled support and motion system positions and stabilizes all beamline components in the undulator system. The system also enables undulators to be retracted from the beam by 80 mm without disturbing the rest of the beamline components. An overview of the support and motion system performance, including achieved results with a production unit that was reserved at Argonne for this purpose, is presented.
BNG, Würzburg
DESY, Hamburg
Babcock Noell GmbH manufactured for DESY 11 identical planar permanent magnet-undulators (8 for the PETRA III upgrade and 3 for FLASH). The positioning accuracy and the movement reproducibility of the two girders, defining the magnetic gap of an undulator, are of vital importance for the quality of the synchrotron light. To reach the desired performance a high quality standard was kept during the choice and procurement of the components, during the high precision machining of the parts and during the assembly phase. After the alignment, laser tracker-measurements were made and evaluated for all the 11 systems. Both, the means by which the accuracy and reproducibility were achieved, and the results of the measurements will be presented here.
CERN, Geneva
The performance reach of the LHC depends on the magnitude of beam losses and the achievable cleaning efficiency of its collimation system. The ideal performance reach for the nominal Phase 1 collimation system is reviewed. However, unavoidable imperfections affect any accelerator and can further deteriorate the collimation performance. Multiple static machine and collimator imperfections were included in the LHC tracking simulations. Error models for collimator jaw flatness, collimator setup accuracy, the LHC orbit and the LHC aperture were set up, based to the maximum extent possible on measurements and results of experimental beam tests. It is shown that combined "realistic" imperfections can reduce the LHC cleaning efficiency by about a factor 11 on average.
CERN, Geneva
The Large Hadron Collider extends the present state-of-the-art in stored beam energy by 2-3 orders of magnitude. A sophisticated system of collimators is implemented along the 27 km ring and mainly in two dedicated cleaning insertions, to intercept and absorb unavoidable beam losses which could induce quenches in the superconducting magnets. 88 collimators per beam are initially installed for the so called Phase 1. An optimized strategy for the commissioning of this considerable number of collimators has been defined. This optimized strategy maximizes cleaning efficiency and tolerances available for operation, while minimizing the required beam time for collimator setup and ensuring at all times the required passive machine protection. It is shown that operational tolerances from collimation can initially significantly relaxed.
CERN, Geneva
BNL, Upton, Long Island, New York
Various LHC injection tests were performed in August and early September 2008 in preparation for the circulating beam operation. These tests provided the first opportunity to measure with beam the available mechanical aperture in two LHC sectors (2-3 and 7-8). The aperture was probed by exciting free oscillations and local orbit bumps of the injected beam trajectories. Intensities of a few 109 protons were used to remain safely below the quench limit of superconducting magnets in case of beam losses. In this paper the methods used to measure the mechanical aperture, the available on-line tools, and beam measurements for both sectors are presented. Detailed comparisons with the expected results from the as-built aperture models are also presented. It is shown that the measurements results are in good agreement with the LHC design aperture.
SLAC, Menlo Park, California
DESY, Hamburg
OXFORDphysics, Oxford, Oxon
ISU, Ames
CLASSE, Ithaca, New York
BNL, Upton, Long Island, New York
KEK, Ibaraki
Funding: Work supported in part by US DOE contract DE-AC02-76-SF00515.
The Interaction Region of the International Linear Collider* is based on two experimental detectors working in a push-pull mode. A time efficient implementation of this model sets specific requirements and challenges for many detector and machine systems, in particular the IR magnets, the cryogenics and the alignment system, the beamline shielding, the detector design and the overall integration. This paper attempts to separate the functional requirements of a push pull interaction region and machine detector interface from the conceptual and technical solutions being proposed by the ILC Beam Delivery Group and the three detector concepts**. As such, we hope that it provides a set of ground rules for interpreting and evaluation the MDI parts of the proposed detector concept’s Letters of Intent, due March 2009. The authors of the present paper are the leaders of the IR Integration Working Group within Global Design Effort Beam Delivery System and the representatives from each detector concept submitting the Letters Of Intent.
*ILC Reference Design Report, ILC-Report-2007-01.
**Materials of IR Engineering Design Workshop, 2007, http://www-conf.slac.stanford.edu/ireng07
KEK, Ibaraki
Fermilab, Batavia
INFN/LASA, Segrate (MI)
DESY, Hamburg
In an attempt at demonstrating an average field gradient of 31.5 MV/m as per the design accelerating gradient for ILC, a program called S1-Global is in progress as an international research collaboration among KEK, INFN, FNAL, DESY and SLAC. The S1-Global cryomodule will contain eight superconducting cavities from FNAL, DESY and KEK. The cryomodule will be constructed by joining two half-size cryomodules, each 6 m in length. The module containing four cavities from FNAL and DESY will be constructed by INFN. The design of this module is based on an improved 3rd generation TTF design. KEK will modify the 6-meter STF cryomodule to contain four KEK cavities. The designs of the cryomodules are ongoing between these laboratories, and the operation of the system is scheduled at the KEK-STF from June 2010. In this paper, the S1-Global cryomodule plan and the module design will be presented. ‘S1-Global collaboration’ as a co-author.
CERN, Geneva
EPFL, Lausanne
IHEP Protvino, Protvino, Moscow Region
Bent crystals are promised to provide a path towards significant improvement of cleaning efficiency for high power collimation systems. In this paper a possible implementation of a crystal-enhanced collimation system is evaluated for the LHC. Simulation studies were performed with the same state-of the art tracking codes as used for the design of the conventional LHC collimation system. The numerical models are described and predictions for the local and global cleaning efficiency with a crystal-based LHC collimation system are presented. Open issues and further work towards a crystal collimation design for the LHC are discussed.
CERN, Geneva
Personnel access to the LHC tunnel will be restricted to varying extents during the life of the machine due to radiation and cryogenic hazards. For this reason a remotely operated modular inspection train, (TIM) running on the LHC tunnel’s overhead monorail has been developed. In order to be compatible with the LHC personnel access system, a small section train that can pass through small openings at the top of sector doors has now been produced. The basic train can be used for remote visual inspection; additional modules give the capability of carrying out remote measurement of radiation levels, environmental conditions around the tunnel, and even remote measurement of the precise position of machine elements such as collimators. The paper outlines the design, development and operation of the equipment including preparation of the infrastructure. Key features of the trains are described along with future developments and intervention scenarios.
SLAC, Menlo Park, California
We present recent progress in the fabrication of a 3D photonic crystal laser accelerator structure. Direct acceleration of electrons by lasers offer promising improvements over traditional RF acceleration techniques in terms of cost, gradient, technology used, and short temporal bunches produced. Microbunching and net acceleration experiments were successfully performed at the E163 facility at SLAC, setting the stage for design, fabrication, and testing of optical structures. This paper describes work done at the Stanford Nanofabrication Facility towards fabricating such structures. A process based on standard optical lithographic techniques was used to fabricate a four layer woodpile photonic crystal with a bandgap centered at 4.55μm and a full width half max of 2.71μm. Infrared spectroscopy measurements were taken and compared with simulations yielding good agreement. SEM images were used to measure fabrication deviations in rod width, rod shape, layer thickness, and alignment, and further simulations are being done to study the effect of these deviations on properties of the accelerating mode excited in the defect of a 20 layer structure currently under design.
UNIFE, Ferrara
IHEP Protvino, Protvino, Moscow Region
INFN-PG, Perugia
Università dell'Insubria & INFN Milano Bicocca, Como
INFN-Roma, Roma
INFN/LNL, Legnaro (PD)
PNPI, Gatchina, Leningrad District
JINR, Dubna, Moscow Region
Università di Roma I La Sapienza, Roma
INFN-Ferrara, Ferrara
CERN, Geneva
INFN-Trieste, Trieste
The H8RD22 collaboration has accomplished an extensive study of axial channeling in the external lines of the CERN SPS. For 400 GeV protons, it was recorded deflection by about 90% of the particles by a short crystal, by far exceeding the performance of previous experiments. Axial channeling with 150 GeV negative hadrons was also firmly observed with deflection capability comparable to the case of positive particles. Near-axis effect such as multiple-volume reflections in a single crystal as a result of the superposition of volume reflections by a series of parallel planes sharing the same axis was investigated with 400 GeV protons. Confirmation of theoretical expectation was observed, in particular most of the particles were deflected by about 50 urad, four times the deflection angle imparted by a single volume reflection of most efficient planes. In this case the angular acceptance was sensitively broader than for the case of channeling. In summary, channeling in axial mode and multi-volume reflections were proven to be two mechanisms for manipulation steering of high-energy particle beams, which side most established techniques such as planar channeling and volume reflection.*
*Contribution on behalf of the H8RD22 collaboration.
KEK, Ibaraki
Crossing different types of resonances is unavoidable for the high beam power operation of the JPARC Main Ring. The ‘lattice’ resonances are cause by the realistic machine imperfection including the field and alignment errors. In addition the ‘space charge’ resonances will lead to the emittance growth. The mechanism of the emittance dilution for the realistic machine imperfection in combination with the space charge effects should be studied in the self-consistent manner. In frame of this report we analyze different coherent modes of the space charge dominated beam at the injection energy for the JPARC Main Ring for some basic operation scenario of the machine. This analysis allows to identify the most dangerous resonances and to understand the effect of the emittance dilution remaining after the resonance correction. The study has been performed by using the PTC{}ORBIT code.
UMAN, Manchester
It is necessity to be able to accurately predict the performance of the any proposed baseline accelerator design in which the effects of couplers, trapped modes, Wakefields, realistic machining and alignment errors as well as numerous other important effects have been taken into consideration. Traditionally used numerical schemes (such as Finite element and Finite difference) require vast resources and time, not only that but the inclusion of realistic defects and misalignments into the baseline configuration will prove time consuming as it will potentially require remeshing of the problem. Here we present a mode matching scheme which utilises a globalised scattering matrix approach that allows large scale electromagnetic field calculations to be obtained rapidly and efficiently. The scalar product of all the S matrices used within this paper has been determined analytically and is calculated only once per transition, adding to the efficiency of the calculation. The influence of cell misalignments and cavity perturbations on the main accelerating linacs of XFEL and CLIC are exhibited. The wake-fields in super-structures and segments of entire modules are also presented
JAI, Oxford
The alignment of the next generation of linear accelerators will be much more critical than that of currently existing machines. This is especially true for very long machines with ultra low emittance beams; such as the ILC and CLIC. The design and study of such machines will require a large number of simulations. However; full simulation of misalignment currently requires computer programs which are very resource intensive. A model which can be used to rapidly generate reference networks with the required statistical properties will be presented. The results for emittance growth in the ILC main linac using the model with Dispersion Matched Steering (DMS) applied are also shown.
CERN, Geneva
CIEMAT, Madrid
In the framework of EUROTeV, a Precision Beam Position Monitor (PBPM) has been designed, manufactured and tested. The new PBPM, based on the inductive BPM presently used in the CERN Clic Test Facility (CTF3), aims to achieve a resolution of 100 nm and an accuracy of 10μm in a 6 mm aperture. A dedicated test bench has been designed and constructed to fully characterize and optimize the PBPM. This paper describes the final design, present the test bench results and reports on the beam tests carried out in the CERN CTF3 Linac.
CERN, Geneva
IN2P3-LAPP, Annecy-le-Vieux
OXFORDphysics, Oxford, Oxon
CEA, Gif-sur-Yvette
To reach the design luminosity of CLIC, the movements of the quadrupoles should be limited to the nanometer level in order to limit the beam size and emittance growth. Below 1 Hz, the movements of the main beam quadrupoles will be corrected by a beam-based feedback. But above 1 Hz, the quadrupoles should be mechanically stabilized. A collaboration effort is ongoing between several institutes to study the feasibility of the “nano-stabilization” of the CLIC quadrupoles. The study described in this paper covers the characterization of independent measuring techniques including optical methods to detect nanometer sized displacements and analyze the vibrations. Actuators and feedback algorithms for sub-nanometer movements of magnets with a mass of more than 400 kg are being developed and tested. Input is given to the design of the quadrupole magnets, the supports and alignment system in order to limit the amplification of the vibration sources at resonant frequencies. A full scale mock-up integrating all these features is presently under design. Finally, a series of experiments in accelerator environments should demonstrate the feasibility of the nanometer stabilization.
CERN, Geneva
IN2P3-LAPP, Annecy-le-Vieux
The demanding nanometer transverse beam sizes and emittances in future linear accelerators results in stringent alignment and nanometer vibration stability requirements. For more than two decades, ground vibration measurements were made by different teams for feasibility studies of linear accelerators. Recent measurements were performed in the LHC tunnel and at different CERN sites on the surface. The devices to measure nanometer sized vibrations, the analysis techniques and the results are critically discussed and compared with former measurement campaigns. The implications of the measured integrated R.M.S. displacements and coherence length for the CLIC stabilization system are mentioned.
CERN, Geneva
The CLIC components will have to be pre-aligned within a tolerance of 10 microns over a sliding window of 200m all along the linacs, before injecting the first beam. Such tolerance is about 30 times more demanding than for the existing machines as the SPS and LHC; it is a technical challenge and a key issue for the CLIC feasibility. In order to define the CLIC alignment strategy from the survey and beam dynamics point of view, simulations have been undertaken concerning the propagation error due to the measurement uncertainties of the pre-alignment systems. The uncertainties of measurement, taken as hypotheses for the simulations, are based on the data obtained on several dedicated facilities. This paper introduces the facilities and the latest results obtained, as well as the simulations performed.
Fermilab, Batavia
BINP SB RAS, Novosibirsk
Understanding slow and fast ground motion is important for the successful operation and design for present and future colliders. Since 2000 there have been several studies of ground motion at Fermilab. Several different types of hydro static water levels have been used to study slow ground motion (less than 1 hertz) seismometers have been used for fast (greater than 1 hertz) motions. Data have been taken at the surface and at locations 100 meters below the surface. Data and results on slow ground motion will be discussed in particular the effects of natural and cultural sources of motion. We also present estimates on the ATL-diffusion coefficients at various locations.
KEK, Ibaraki
KEKB is a double-ring collider with a circumference of 3016 m. The two rings were built side-by-side in the TRISTAN tunnel, 11 m below ground. KEKB has been operating successfully for about 10 years, since 1999, and its peak luminosity continues to improve. During the summer shutdown of 2008, the magnet tilts were measured for the first time since installation and it was found that some magnets were rotated over time. The tunnel level marker and the magnet height were also surveyed. The south region of the tunnel is sinking, resulting in magnet level changes. The survey results will be reported in this paper.
NSRRC, Hsinchu
TPS (Taiwan Photon Source) is a new 3GeV ring to be constructed at NSRRC Taiwan. A motorized magnet girder system with 6 cam movers on 3 pedestals had been designed and tested to provide 6-axis precise adjustments. With 3 consecutive girders to form one section, there will be 72 girders in the whole ring. In order to align the girders precisely and quickly with less manpower, considering the deformation of the floor and limited space in the tunnel also frequent earthquakes in Taiwan, a whole-ring girders auto alignment system was thus proposed. This system consists of touched sensors between consecutive girders and laser PSD system between straight section girders in addition with electric leveling sensors on each girder. The system operating algorithm had been defined and program also fulfilled to be tested on a 3 girders prototype system. The detailed system design and testing results would be described in this paper.
OXFORDphysics, Oxford, Oxon
JAI, Oxford
DESY, Hamburg
Funding: work supported by STFC in the LC-ABD collaboration and by the Commission of the European Community, 6th Framework Programme, Structuring the European Research Area, contract number RIDS-011899
The Linear Collider Alignment and Survey group has completed experiments with a prototype robotic survey train for the ILC called the RTRS (Rapid Tunnel Reference Surveyor). Calibration of the RTRS is the most difficult part of data analysis, involving advanced mathematical methods to obtain constraint independent calibration parameters and errors. We show how sub-system data analysis provides input errors for the calibration process. We present the mathematical formalism used and results from the calibration of one of the three cars.
LNLS, Campinas
The UVX electron storage ring at the Brazilian Synchrotron Light Laboratory (LNLS) was recently equipped with active current shunt circuits that allow for individual variation of the quadrupole magnet strengths. This allows us to apply the widely used technique of beam-based alignment (BBA) to calibrate the electrical center offset of the BPMs with respect to the magnetic center of the closest quadrupole. In this report we present the BBA experimental results and an analysis of the resolution of the method in the case of the LNLS UVX storage ring.
CERN, Geneva
Fermilab, Batavia
Funding: Work partly supported by Fermilab, operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy
Through May to September 2008, further beam commissioning of the SPS to LHC transfer lines was performed. For the first time, optics and dispersion measurements were also taken in the last part of the lines, and into the LHC. Extensive trajectory and optics studies were conducted, in parallel with hardware checks. In particular dispersion measurements and their comparison with the beam line model were analysed in detail and led to propose the addition of a “dispersion-free” steering algorithm in the existing trajectory correction program.
CERN, Geneva
In the main linac of the compact linear collider (CLIC) the beam induced wakefield and dispersive effects will be strong. In the paper the reference beam-based alignment procedure for the new CLIC parameters is specified and the resulting tolerances for static imperfections are detailed.
TU Darmstadt, Darmstadt
Funding: Supported by DFG via SFB 634
Operational Experience at the Darmstadt superconducting linac (S-DALINAC) showed unexpected effects on beam dynamics and beam quality. So operators could observe transverse beam deflections by changing phases of the SRF-Cavities. Furthermore there has been occurred a growth of normalized tranverse emittance by a factor of 2. The beam current in the S-DALINAC does not exceed 60 μA so space-charge effects could be eliminated to be the reason for the observations. In this work the effect of misalignment of the SRF-Cavities in the linac has been examined using beam-dynamic simulations with the tracking code GPT and measurements on the electron beam of the S-DALINAC. By measuring the transverse deflection of the beam by changes of the phases of the SRF-Cavities and comparing results with GPT-simulations a misalignment of the 5-cell capture cavity and first 20-cell cavity of several mm in both transverse directions could be found. This misalignment can explain transverse deflections as well as emittance growth. A correction of misalignment has been carried out using the described results. First measurements showed no more emittance growth and less beam-deflections by SRF-Cavities.
JAI, Egham, Surrey
Royal Holloway, University of London, Surrey
OXFORDphysics, Oxford, Oxon
KEK, Ibaraki
Funding: STFC LC-ABD Collaboration, Royal Society, Daiwa Foundation, Commission of European Communities under the 6th Framework Programme Structuring the European Research Area, contract number RIDS-011899
The KEK Accelerator Test Facility (ATF) extraction line laser-wire system has been upgraded, enabling the measurement of micron scale transverse size electron beams. The most recent measurements using the upgraded system are presented, including the major hardware upgrades to the laser transport, the laser beam diagnostics line, and the mechanical control systems.
UCLA, Los Angeles, California
INFN/LNF, Frascati (Roma)
ENEA C.R. Frascati, Frascati (Roma)
It has been suggested that an ultra-short, very low charge beam be used to drive short wavelength single-spike operation at the SPARC FEL. This paper explores the development and construction of a longitudinal diagnostic capable of completely characterizing the radiation based on the Frequency-Resolved Optical Gating (FROG) technique. In particular, this paper explores a new geometry based on a Transient-Grating (TG) nonlinear interaction and includes studies of start to end simulations for pulses at the SPARC facility using GENESIS and reconstructed using the FROG algorithm. The experimental design, construction and initial testing of the diagnostic are also discussed.
LBNL, Berkeley, California
BNL, Upton, Long Island, New York
The performance of feedback control systems is limited by latency. The hardware-based fast communication system described here offers means for deterministic, fault-tolerant data transmission for feedback systems requiring low-latency communications, such as orbit feedback and Radio Frequency (RF) controls.
SLAC, Menlo Park, California
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
JAI, Oxford
KEK, Ibaraki
IHEP Beijing, Beijing
LAL, Orsay
Royal Holloway, University of London, Surrey
IN2P3-LAPP, Annecy-le-Vieux
OXFORDphysics, Oxford, Oxon
ATOMKI, Debrecen
CERN, Geneva
DESY, Hamburg
Fermilab, Batavia
Kyungpook National University, Daegu
PAL, Pohang, Kyungbuk
Kyoto ICR, Uji, Kyoto
ICEPP, Tokyo
University of Tokyo, Tokyo
UCL, London
BNL, Upton, Long Island, New York
Tohoku University, Graduate School of Science, Sendai
UMAN, Manchester
Hiroshima University, Graduate School of Science, Higashi-Hiroshima
Cockcroft Institute, Warrington, Cheshire
ATF2 is a final-focus test beam line that attempts to focus the low-emittance beam from the ATF damping ring to a beam size of about 37 nm, and at the same time to demonstrate nm beam stability, using numerous advanced beam diagnostics and feedback tools. The construction is well advanced and beam commissioning of ATF2 has started in the second half of 2008. ATF2 is constructed and commissioned by ATF international collaborations with strong US, Asian and European participation.
JAI, Oxford
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
PAMELA (Particle Accelerator for MEdicaL Applications) is a design for a non-scaling Fixed Field Alternating Gradient accelerator facility for Charged Particle Therapy, using protons and light ions such as carbon to treat certain types of cancer. A lattice has been designed which constrains the variation of betatron tunes through acceleration and thus avoids integer resonance crossing and beam blow-up. This paper outlines the design and performance of this proposed PAMELA lattice.
LBNL, Berkeley, California
Funding: This research was performed under the auspices of the U.S. DOE at the Lawrence Livermore and Lawrence Berkeley National Laboratories under Contracts No. DE-AC52-07NA27344 and No. DE-AC02-05CH11231.
A recent theory in Ref. * analyzes small-amplitude oscillations of the transverse beam centroid (center of mass) in solenoidal transport channels. This theory employs a transformation to a rotating Larmor frame to simply express the centroid response to mechanical misalignments (transverse center displacements and tilts about the of the longitudinal axis of symmetry) of the solenoid and initial centroid errors. The centroid evolution is expressed in terms of a superposition of the centroid evolving in the ideal aligned system plus an expansion in terms of "alignment functions" that are functions of only the ideal lattice with corresponding amplitudes set by the solenoid misalignment parameters. This formulation is applied to analyze statistical properties of beam centroid oscillations induced by solenoid misalignments. Results are compared to experiments at the NDCX experiment at the LBNL. It is found that contributions to oscillation amplitudes from tilts are significantly larger than contributions from offsets for expected parameters. Use of the formulation to optimally steer the centroid back on-axis with limited diagnostic measurements is also discussed.
* S.M. Lund, C.J. Wootton, and E.P. Lee, "Transverse centroid oscillations in solenoidally focused beam transport lattices," accepted for publication, Nuc. Inst. Meth. A.
UCLA, Los Angeles
PBPL, Los Angeles
The Micro-Accelerator Platform, a laser-driven accelerating device measuring less than a millimeter in each dimension, has a variety of applications in industry and medicine. The structure consists of two parallel slabs, with each possessing reflective surfaces and with one having periodic slots which allows transversely incident laser light to enter the gap between the two planes. The resonance of the electric field created in the gap can be measured indirectly through the spectral response of the device. Using a combination of an interferometer and a fiber coupled spectrometer, prototype structures are aligned and measured. With the aid of a nanometer-accuracy positioning device, the bottom slab (a mirror) is aligned with the top slotted-structure. The interferometer and a low power laser are used to position the slabs. A 800nm Titanium-Sapphire oscillator with a bandwidth of greater than 100nm is used for the spectral measurements. The spectra of both transmitted and reflected beams have been measured for a number of structures and are compared to simulation results. Various improvements to the initial measurement system as well as alternative future approaches are discussed.
SLAC, Menlo Park, California
The Flight Simulator is a Matlab middleware layer which uses the Lucretia beam tracking engine and a lower level EPICS control system to allow the development of beam control and monitoring algorithms in a simulation environment that appears identical to the that of the control room. The goal of ATF2 is to test a novel compact final final focus optics design intended for use in future linear colliders. The newly designed extraction line and final focus system will be used to produce a 37nm vertical waist from the extracted beam. Alignment of the magnetic elements is of vital importance for this goal and it is expected that beam-based alignment (BBA) techniques will be necessary to achieve the necessary tolerances. This paper describes a package for the beam-based alignment of quadrupole and sextupole magnets in the ATF2 damping ring, extraction line, and final focus system. It brings together several common techniques for the alignment of magnetic elements, and has been implemented as a GUI-based tool that may be used on its own, or integrated with other routines. The design of this package is described, and simulation and beam results are shown.
IAP, Frankfurt am Main
GSI, Darmstadt
A new CW-RFQ will be built for the upgrade of the HLI (High Charge State Injector) of GSI for operating with a 28 GHz-ECR-Ion source and simultaneous increase of the beam duty cycle from 25% to 100 %. The new HLI 4-rod RFQ will accelerate charged ions from 4 keV/u to 300 keV/u for the injection into the IH-structure The design had been optimized to get a rather short structure with LRFQ=2m to match the available RF-power of max. 60 kW in cw. High beam transmission, a small energy spread and small transverse emittance growth and good input matching were design goals. Properties of this CW-RFQ and status of project will be presented.
KAERI, Daejon
Funding: This work is supported by MEST of the Korean Government
A 100 MeV DTL as a main accelerating section of the PEFP proton linac is under development. The PEFP proton linac consists of a 50 keV proton injector based on a duoplasmatron ion source, 3 MeV four-vane RFQ, 20 MeV DTL and 100 MeV DTL. The 100 MeV DTL is composed of 7 tanks and each tank is an assembly of 3 sections. The tank is made of seamless carbon steel and inside surface is electroplated with copper. Each drift tube contains an electroquadrupole magnet which is made of hollow conductor and iron yoke with epoxy molding. Following the fabrication of tanks and drift tubes, a precise alignment of drift tubes and field flatness tuning procedure are performed. Currently four DTL tanks out of seven are completed and the rest are under fabrication. The status of development and test results of the fabricated parts are reported in this paper.
Sigmaphi, Vannes
CEA, Gif-sur-Yvette
LPSC, Grenoble
The paper presents the magnetic measurements of the RACCAM prototype FFAG dipole, manufactured by SIGMAPHI for the Raccam ANR Medical FFAG project. This magnet prototyping work, started early 2006, is being performed in collaboration between the IN2P3/LPSC Laboratory team and SIGMAPHI. This paper describes the magnetic measurement results and comparison with Tosca simulation.