LBNL, Berkeley, California
Funding: This work was supported by the Director, Office of Science, U. S. Department of Energy under Contract No. DE-AC02-05CH11231.
Beam stability is one of the most important properties for the users of a synchrotron light source. Beam stability includes the stability of orbit, beamsize, current (lifetime), energy, and energy spread. As light sources are generating higher brightnesses, adding fast switching variable polarization devices, and and producing smaller source sizes, there is a necessity for continuous improvements in beam stability. In this talk an overview of the state of the art in beam stabilization and remaining challenges for beam stability are presented.
BNL, Upton, Long Island, New York
Hundred megawatt level fast ramping power converters to drive proton and heavy ion machines are under research and development at accelerator facilities in the world. This is a leading edge technology. There are several topologies to achieve this power level. Their advantages and related issues will be discussed.
ORNL, Oak Ridge, Tennessee
Solid-state based high-power modulators utilize new technology, yet must meet the operational needs of a high reliability facility. This modulator technology is in use at SNS, and is under consideration and development for future machines, such as the ILC and PEFP. Through operational experience and a sustained development effort, a number of improvements have been deployed in the SNS modulator system to meet the high availability demands of operating facilities. The operating experience and development effort of the world-wide community will also be reviewed.
BNL, Upton, Long Island, New York
Funding: US DOE Office of Basic Energy Sciences
Feasibility studies for two families of corrector magnets for NSLS-II are presented. The first family of magnets are generalizations of figure eight quadrupoles using rotationally symmetric breaks in the return yoke to fit in available space. Properties specific to figure eight magnet are identified. The second type of magnet is a combined sextupole/dipole trim.
BNL, Upton, Long Island, New York
Funding: US DOE Office of Basic Energy Sciences
The design and measurement of the NSLS-II ring quadrupoles prototypes are presented. These magnets are part of a larger prototype program described in [1]. Advances in software, hardware, and manufacturing have led to some new level of insight in the quest for the perfect magnet design. Three geometric features are used to minimize the first three allowed harmonics by way of optimization. Validations through measurement and confidence levels in calculations are established.
CIAE, Beijing
CYCIAE-100 is a 100 MeV, 200 muA H- cyclotron being constructed at CIAE. The tolerance of the magnetic field is as tight as 1.2 Gauss for isochronous field and 2 Gauss for first harmonics. Due to the absence of coil adjusting in this machine, a measure that helps to achieve a more compact structure (435 ton for the main magnet), the imperfection hence becomes a much more critical factor in our consideration. The effects by the various kinds of imperfection are investigated numerically and the imperfection fields are predicted for beam dynamics simulation, serving as a basic guidance in the magnet construction for CYCIAE-100. Some of the important results will be reported in this paper, including
- the deformation of the main magnet by the gravity itself, 480 ton EM force and 120 ton vacuum pressure,
- segregation, inclusion and contraction cavity induced by the casting procedure,
- fabrication and assembling tolerance, and
- thermal deformation.
Fermilab, Batavia
Funding: Work supported by the U.S. Department of Energy
The fabrication of the multi-element corrector magnets for the Fermilab Booster synchrotron has just been completed. These water-cooled packages include six different corrector types - normal and skews oriented dipole, quadrupole and sextupole elements. They will provide full orbit control, tune and chromaticity of the beam over the whole range of Booster energies, from 0.4 GeV to 8 GeV. During production, a set of quality assurance measurements were performed, including special thermal tests. This paper summarizes the results from these measurements as well as discussing some specific steps of the magnet fabrication process.
HIT, Heidelberg
GSI, Darmstadt
MPI-K, Heidelberg
The use of hadron beams delivered by normal conducting synchrotrons is highly attractive in various fundamental research applications as well as in the field of particle therapy. These applications require fast synchrotron operation modes with pulse-to-pulse energy variation and magnetic field slopes up to 10 T/s. The aims are to optimize the duty-cycle or to minimize treatment times for the patients as well as to provide extremely stable properties of the extracted beams, i.e. position and spill structure. Studies performed at the SIS18 synchrotron at GSI showed that not only the dipoles but the quadrupoles as well significantly contribute to the underlying time constants of the slowly extracted beam. An attempt has been made to measure the magnetic fields in synchrotron magnets with high precision and speed comparable to the current measurement with a DCCT. Additional magnetic field monitoring includes the retarding effects into the current control feedback loop neglecting the unfavourable dynamic effects from hysteresis and eddy currents. The presentation describes this controls approach, the results obtained at the HIT synchrotron and the SIS18 at GSI will be discussed.
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.
HUST, Wuhan
Funding: Work supported by National Nature Science Foundation of China (10435030) and National Science Foundation for Post-doctoral Scientists of China (20080430973)
Low energy compact cyclotrons for short-life isotopes production delivered to the Positron Emission Tomography (PET) facilities have foreseeable prospects with growing demands in medical applications. The Huazhong University of Science and Technology (HUST) proposed to develop a 10MeV PET cyclotron CYCHU-10. The design study of the main magnet and the central region was introduced. A matrix shaping method with the radial fringe field effect and artificial control was adopted to obtain field isochronisms precisely. The central region was optimized to attain 35° RF phase acceptance and low vertical beam loss rate.
JLAB, Newport News, Virginia
Funding: Work supported by the US DOE Contract #DE-AC05-060R23177 and the Commonwealth of Virginia.
The characteristics of the system of “SF” Sextupoles for the infrared Free Electron Laser Upgrade at the Thomas Jefferson National Accelerator Facility (JLab) are described. These eleven sextupoles possess a large field integral (2.15 T/m) with ± 0.01% field quality over a 150 mm width within a very short effective length (150 mm pole length) and have field clamps for fast field roll-off. The field integrals reproduce extremely well with good absolute resolution (± 0.1%). The simple, two-dimensional shape pole tips (directly from the original 3-D RADIA magnetic model) of these “all ends” magnets include the correction for end fields. Magnetic measurements are compared to the model. The system’s hysteresis protocol and power supplies were also used for the measurement process to enhance reproducibility in service, a recent initiative at JLab. The intricacies of magnetic measurement using the JLab field probe based Stepper Stand are described. The challenges of developing the in-house design power supplies for these magnets, based on use of a low quality supply brought to 0.001% current regulation by a CAN-Bus control are described.
JLAB, Newport News, Virginia
Jefferson Lab’s Continuous Electron Beam Accelerator Facility (CEBAF) currently has maximum beam energy of 6 GeV. The 12 GeV Upgrade Project will double the existing energy and is currently scheduled for completion in 2014. This doubling of energy requires modifications to the beam transport system which includes the addition of several new magnet designs and modifications to many existing designs. Prototyping efforts have been concluded for two different designs of quadrupole magnets required for the upgrade. The design, fabrication and measurement will be discussed.
Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
BNG, Würzburg
GSI, Darmstadt
GSI had manufactured a prototype of a fast cycling superconducting dipole magnet at Babcock Noell GmbH. This is the first full size magnet for the SIS100 synchrotron at the future Facility for Antiproton and Ion Research (FAIR) in Darmstadt / Germany. In close collaboration with GSI, the magnet was technologically developed, manufactured and assembled by Babcock Noell. The system was successfully tested at GSI reaching the nominal cycling performance, including the high ramping rate of 4 T/s and the maximum field of 2.1 T. Especially the superconducting cable, the coils and the iron yoke are subject to strong mechanical and thermal stresses. Here we describe the details on the fabrication of these components and give an outlook on possible improvements of the manufacturing technologies, applicable to future prototypes and series magnets for SIS100.
CERN, Geneva
The start-up of the LHC has provided the first field test for the concept, functionality and accuracy of FiDeL, the Field Description for the LHC. FiDeL is primarily a parametric model of the transfer function of the main field integrals generated by the series of magnets in the LHC powering circuits, from main optical elements to high-order harmonic correctors, both superconducting and normal-conducting magnets. In addition, the same framework is used to predict harmonic errors of both static and dynamic nature, and forecast appropriate corrections. In this paper we give a description of the level of detail achieved in the model and the rationale adopted for the LHC start-up. Beam-based measurements have been used for an assessment of the first-shot accuracy in the prediction of the current setting for the main arc magnets*.
*The work reported has been performed by the authors and the FiDeL Team
CERN, Geneva
The Large Hadron Collider beams are brought into collision by superconducting orbit corrector magnets which generate the parallel separation and crossing angles at the interaction points during the different cycle phases. Unfortunately, the magnetic field errors that result from hysteresis effects in the operation region of these magnets lead to unwanted orbit perturbations. In a previous paper, it has been shown that these effects are within the perturbations coming from beam-beam interactions for the MCBC and the MCBY magnets but are significant in the case of the MCBX magnets. This paper presents a refined model of their field in the frame of the Field Description for the LHC (FiDeL), the results obtained from new magnetic measurements in cold conditions to test the model, the powering mechanism employed to maximize their field reproducibility, and the impact the modeling error is predicted to have on the LHC orbit.
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.
Muons, Inc, Batavia
NHMFL, Tallahassee, Florida
Funding: Supported in part by DOE SBIR grant DE-FG02-08ER85024
Optical fibers can be imbedded within new high temperature superconductor (HTS) magnets to monitor strain and temperature, to detect quenches, and, in the case of AgX/Ag/Bi2Sr2CaCu2Ox, (Bi2212) wire magnets, to serve as a heat treatment process monitor for wind-and-react (W&R) manufacturing. The W&R process requires that the optical fibers be installed before the Bi2212 heat treatment, one important issue is whether the fibers survive the 890 oC heat treatment so as to monitor the heat treatment and to serve subsequently as a low temperature monitor. Here, Au-coated optical fibers are attached to Bi2212 wires and processed with the typical reaction cycle. The Bi2212 superconductor is then evaluated for performance degradation due to the presence of the fiber and the fiber is evaluated for performance degradation due to the heat treatment and viability as a heat treatment process monitor. Two approaches to fiber optic sensing are used: a fiber Bragg grating and Rayleigh scattering
ANL, Argonne
Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The baseline configuration of the proposed International Linear Collider includes superconducting helical undulators as a scheme to produce positrons. This paper presents a conceptual design of the magnetic field measurement system for helical undulators with the undulator axis in a horizontal direction at liquid helium temperature. The system consists of a cryomodule and a linear stage unit with a travel length of approximately 3.5 m. The linear stage unit provides the motion control for the Hall probe housing, which is connected to a small-diameter carbon fiber rod inside bellows-flange connections. Stainless steel bellows are at the same vacuum pressure as the cold mass in the cryomodule. A linear encoder is used for motion control of the stage, but precise position measurement of the Hall probe relies on the laser interferometer system.
CLASSE, Ithaca, New York
Funding: Work supported by National Science Foundation under contract DMR 0225180
The paper describes the design as well as short prototype and the prototype test result of undulator magnet planned for use in Cornell Energy Recovery Linac. The prototype has pure permanent magnet (PPM) structure with 24mm period, 5mm diameter round gap and is 30cm long. In comparison with conventional undulator magnets it has: a) full X-ray polarization control; b) 40% stronger magnetic field in linear and approximately 2 times stronger in circular polarization modes; c) compactness. These advantages were achieved through a number of non-conventional approaches. Among them is control of the magnetic field strength via longitudinal motion of the magnet arrays. The moving mechanism is also used for x-ray polarization control. The compactness is achieved using a recently developed permanent magnet soldering technique for fastening PM blocks. We call this device a "Delta" undulator after the shape of it's PM blocks.
ISSP/SRL, Chiba
JASRI/SPring-8, Hyogo-ken
RIKEN Spring-8 Harima, Hyogo
A 27-m polarization-controlled undulator that consists of four horizontal and four vertical figure-8 undulator segments and seven phase shifters will be installed at SPring-8 as the most highly brilliant soft x-ray source for the material science beamline of the University of Tokyo. Each phase shifter controls the radiation phase between undulator segments by giving a bump orbit to the electron beam with its magnetic field to generate horizontal, vertical and circular polarization states. High reproducibility and stability of the phase control and fast helicity switching of the circular polarization radiation are required for the phase shifter. We designed and fabricated a phase shifter prototype to satisfy these requirements. The phase shifter prototype consists of three H-type dipole magnets and the yokes are made of 0.1-mm-thick permalloy laminations united and insulated by varnish. Various field measurements of the prototype were performed to evaluate the performance. In this paper, we will present the phase shifter prototype for the 27-m polarization-controlled undulator and its performance.
CERN, Geneva
The Compact LInear Collider, under study, requires vacuum chambers with a very small aperture, of the order of 8 mm in diameter, and with a length up to around 2 m for the main beam quadrupoles. To keep the very tight geometrical tolerances on the quadrupoles, no bake out is allowed. The main issue is to reach UHV conditions (typically 10-9 mbar static pressure) in a system where the vacuum performance is driven by water outgassing. For this application, a thin-walled stainless steel vacuum chamber with two ante chambers equipped with NEG strips, is proposed. The mechanical design, especially the stability analysis, is shown. The key technologies of the prototype fabrication are given. Vacuum tests have been carried out on the prototypes. The test set-up as well as the performance of the pumping system are presented and compared with predictions.
CERN, Geneva
The LHC collider has recently completed commissioning at CERN. At four points around the 27 km ring, the beams are put into collision in the centre of the experiments ALICE, ATLAS, CMS and LHCb which are installed in large underground caverns. The ‘experimental vacuum systems’ which transport the beams through these caverns and collision points are a primary interface between machine and experiment and were developed and installed as one project at CERN. Each system has a different geometry and materials as required by the experiment. However, they all have common requirements from the machine, and use many common technologies developed for the project. In this paper we give an overview of the four systems stressing the similarities between them. We explain the technologies that were developed and applied for the installation, test, bakeout and subsequent closure of the experimental vacuum systems. We also discuss lessons learnt from the project.
NSRRC, Hsinchu
National Tsing Hua University, Hsinchu
The Taiwan Photon Source (TPS) vacuum system has been designed for a 3 GeV electron storage ring of 24DBA lattice, 518.4 m circumference, 24 unit cells and 24 long straight sections of 6 in 12 m and 18 in 7 m. The vacuum ducts for each cell made from thick aluminum plates and extruded aluminum beam pipes will be precisely machined and welded for obtaining a low impedance with small quantity of flanges and bellows. The beam ducts in long straight sections will be flat extruded aluminum pipes of 10 mm vertical height inside which will be ready for installation of the undulators without breaking the vacuum. The BPMs, 2 in each straight sections and 5 in each cells, will be fixed on the ground or on the girder rigidly through the strong supports maintaining a displacement of < 0.1 micron against the stress force of 10 kg from the beam ducts. The small aperture of 10 mm inside the aluminum bending chamber rejects the PSD outgas from the crotch absorbers backfilled to the beam channel, while the surface of bending chamber will be cleaned with ozonated water to reach lower thermal outgassing rate that maintains a much lower averaged pressure below 100 nPa inside the beam ducts.
KEK, Ibaraki
A 6-m cryomodule, which includes four Tesla-like 9-cell cavities, was assembled and installed in the STF tunnel in April, 2008. After cooldown of the cryomodule, high power tests of four cavities had been carried out at 2 K from September to December, 2008. A cavity package consists of a 9-cell niobium cavity with two HOM couplers, an input coupler with a cold and a warm rf window, and a frequency tuning system with a mechancal and a piezo tuner. The performance as a total sc cavity system was checked in the cryomodule test with high rf power. One of the cavities was achieved a stable pulsed operation at 32 MV/m higher than the specific operating gradient (31.5 MV/m) in ILC. The maximum accelerating gradients (Eacc,max) obtained in the vertical cw tests was maintained or slightly improved in the cryomodule tests with a pulsed operation of 1.5 msec and 5 Hz. Compensation of Lorentz force detuning at 31 MV/m was successfully demonstrated by using piezo tuner and pre-detuning.
CERN, Geneva
A first stage collimation system has been installed for the 2008 first beam commissioning of the LHC. It consists of 88 collimators distributed around the ring and the two injection lines. Each collimator has two jaws for which positions and angles must be controlled and monitored with high precision. The LHC collimation system was put into operation from July to October 2008. The installed system is described and the first results from system operation without and with beam are presented. In particular, it is shown that the LHC collimation system achieved the specified accuracy and reproducibility of jaw positioning. The next steps in collimation commissioning and the expected system evolution are described. Planned system upgrades for high LHC beam intensities are outlined.
ANL, Argonne
CEA, Gif-sur-Yvette
JLAB, Newport News, Virginia
Fermilab, Batavia
NHMFL, Tallahassee, Florida
IIT, Chicago, Illinois
Funding: DOE/OHEP
We have begun using Atomic Layer Deposition (ALD) to synthesize a variety of surface coatings on coupons and cavities as part of an effort to produce rf structures with significantly better performance and yield than those obtained from bulk niobium, The ALD process offers the possibility of conformally coating complex cavity shapes with precise layered structures with tightly constrained morphology and chemical properties. Our program looks both at the metallurgy and superconducting properties of these coatings, and also their performance in working structures. Initial results include: 1) evidence from point contact tunneling showing magnetic oxides can be a significant limitation to high gradient operation, 2) experimental results showing the production sharp niobium/oxide interfaces from a high temperature bake of ALD coated Al2O3 on niobium surfaces, 3) results from ALD coated structures.
ANL, Argonne
Funding: Work supported by U.S.Department of Energy, Office of Science, Office of Basic Energy Science, under Contract No. DE-AC02-06CH 11357
Recently, a new SLED test stand located in the Advanced Phone Source linac klystron gallery was developed using a spare modulator-klystron system and a recently developed prototype water station. The new test stand will be used to condition, tune and perform rf measurements on spare SLEDs without interfering with normal daily linac operations. This will allow technical groups to replace a low-performance SLED from one of the operational linac sectors with a fully conditioned SLED. The pre-conditioned SLED is expected to require less conditioning time after being put into operation compared to an unconditioned SLED. As an additional benefit, the prototype water station system developed to replace aging linac water systems can be tested under realistic conditions. In this paper, we describe the test stand design, prototype water station system, and first results using it to condition SLEDs and perform SLED rf measurements.
Euclid TechLabs, LLC, Solon, Ohio
KEK, Ibaraki
Ceramics Ltd., St. Petersburg
Fermilab, Batavia
Funding: This work was supported by the US Department of Energy
Euclid TechLabs LLC is developing BST based ferroelectric elements designed to be used as the basis for new advanced accelerator components operating in the 1.3 GHz frequency range and intended for Project X and ILC applications. These new ferroelectric elements are designed for the fast active tuner for SC cavities that can operate in air at low biasing DC fields in the range of 15 kV/cm. The BST(M) material (BST ferroelectric with Mg-based additives) allows fast switching and tuning in vacuum and in air both; switching time of material samples < 10 ns has been demonstrated. The overall goal of the program was to design an L-band externally-controlled fast ferroelectric tuner for controlling the coupling of superconducting RF cavities for the future linear colliders. The tuner prototype has been built; a time response of <30 ns, or 1 deg. in 0.5 ns has been reached. . The following problems are addressed: (i) lowering the losses in the ferroelectric material; (ii) improving the technique of the ferroelectric element metallization and brazing; and (iii) improvement breakdown threshold at high voltage bias.
Fermilab, Batavia
Muons, Inc, Batavia
Funding: Supported in part by FRA DOE contract number DE-AC02-07CH11359
RF cavities below 800 MHz are large, so alternative cavities at low frequencies are needed. Novel dielectric loaded RF cavities will allow smaller diameter cavities to be designed; changing the frequency of a cavity design would be as simple as changing the dielectric cylinder insert material or inner radius of the dielectric in the cavity. This paper discusses RF cavities loaded with dielectric material that could be used in various ways for muon facilities. The examples given are for 400 and 800 MHz cavities. Our initial motivation was to use dielectric to reduce the radial size of gas-filled cavities in helical cooling channels, but dielectric-loading has potential use in vacuum cavities for suppression of dark current emission. We also studied cavities that can be used for the phase rotation channel in the front end of a muon collider or neutrino factory.
Muons, Inc, Batavia
Fermilab, Batavia
Funding: Supported in part by USDOE Contract. DE-AC05-84-ER-40150 and by FRA DOE contract number DE-AC02-07CH11359
Magnetrons are low-cost highly-efficient microwave sources, but they have several limitations, primarily centered about the phase and frequency stability of their output. When the stability requirements are low, such as for medical accelerators or kitchen ovens, magnetrons are the very efficient power source of choice. But for high energy accelerators, because of the need for frequency and phase stability–-proton accelerators need 1-2 degrees source phase stability, and electron accelerators need .1-.2 degrees of phase stability–-they have rarely been used. We describe a novel variable frequency cavity technique which will be utilized to phase and frequency lock magnetrons.
GSI, Darmstadt
The 'Facility of Antiproton and Ion Research' (FAIR) project will be realized at the 'GSI Helmholtzzentrum für Schwerionenforschung GmbH' (Darmstadt, Germany) in the scope of a large international collaboration. One of the FAIR storage rings is the collector ring (CR) whose main purpose is to allow a fast cooling of secondary beams (rare isotopes and antiprotons). The RF system of the collector ring has to allow pulsed operation (40kV, duty cycle 5e-4) as well as continuous operation (2kV) in the frequency range of 1.2 to 1.4MHz. The detailed conceptual design of this RF system is introduced here. It will be based (similar to the existing RF system 'SIS18 bunch compressor' which will also be presented at PAC09) on two inductively loaded quarter wavelength coaxial resonators operating on a common ceramic gap. The resonator will be loaded with twelve ring cores (rout=313mm, rin=145mm, h=25mm) of a cobalt based amorphous magnetic alloy (VitroVac6030F); it will be cooled by forced air. The cavity will be driven by a push-pull amplifier operated in class A consisting of two tetrodes (TH555A) that will be coupled inductively to the cavity.
CLASSE, Ithaca, New York
Funding: Work supported by NSF Grant PHY 0131508
This paper reports results of cold measurements characterizing the electro-mechanical properties of the Cornell ERL injector cryomodule, which houses five superconducting niobium elliptical 2-cell cavities developed for a high-current (100 mA) low-emittance electron beam. Each cavity is equipped with a blade tuner. The Cornell ERL blade tuner is a modified version of the INFN-Milano design, and incorporates 4 piezoelectric actuators and accelerometers enabling concurrent slow/fast cw RF frequency control and mechanical vibration measurements. Cavity microphonics and fast tuner electro-mechanical transfer functions for all of the cavities have been measured and show the feasibility of stable feedback control at microphonic noise frequencies below ~100 Hz.
Fermilab, Batavia
DESY, Hamburg
A series of four automatic tuning machines for 9-cell TESLA-type cavities are being developed and fabricated through a collaboration between DESY, FNAL and KEK. These machines are intended to support high-throughput cavity fabrication for construction of large SRF-based accelerator projects. Two of these machines will be delivered to cavity vendors for the tuning of XFEL cavities. The control system for these machines must support a high level of automation adequate for industrial use by non-expert operators. This paper describes the control system hardware and software designs, and shows preliminary results obtained with a tuning machine prototype.
KEK, Ibaraki
Kyoto ICR, Uji, Kyoto
The inspections of the superconducting RF cavities seem essential in achieving high accelerating gradient. The Kyoto camera system is a good tool to survey a defect location and to be analysis a defect shape in the inner surface of the superconducting rf cavities. The cavity inspections of the AES, ACCEL, ZANON and STF Baseline cavities were inspected to study relations between a defect shape and a heating gradient of the superconducting rf cavities. The STF Baseline #5 and #6 cavities with each surface treatment (as received, after Pre-EP, after EP-1, and after vertical test with EP-2) were inspected to trace a changing spots shape. The full inspection of the EBW seam, the HAZ (heat affected zone) and hot spots region were carried out before EP-2 process and a vertical test then the shape analysis of a discovered spots was done. The vertical tests of these cavities with T-map of fixed 9-cell type were measured at STF from September 2008. The inspection and shape analysis of these cavities were made after vertical tests for based on T-map data. The result of vertical tests and changing a shape of a discovered spots with EP-2 process will be presented.
KEK, Ibaraki
TIPC, BeiJing
A pulsed RF operation of four units of 9-cell L-band (1.3 GHz) cavities in a horizontal cryostat (cryo-module) was conducted in 2008 as part of R&D efforts at STF at KEK for ILC. A series of compensation experiments were conducted for Lorentz-detuning effects, which are critically important for pulsed RF operation of high-gradient linacs based on superconducting cavity technologies. The experiments were done at a repetition rate of 5 Hz with RF pulses of a width of 1.5 msec, and the typical accelerating gradient within the cavities was 20 Â 32 MV/m. Two types of compensation techniques have been tested. In a “feed-forward” method, piezo actuators on individual cavity tuners are activated to mechanically control the tuning of the cavity in synchronization with the RF pulses. In a “feed-back” method, the low-level RF system is driven so as to maintain the average of “I” and “Q” components of the cavities as constant. This paper reports the experimental results using the various parameters of the piezo control to compensate the effect of Lorentz-detuning. These results are consistent with the numerical calculation postulating that two mechanical modes mainly contribute to the effect.
CRE, Wuppertal
The modular architecture of high power solid state rf amplifiers for the frequency range of 72 to 3000MHz is described. The characteristic features of the modular components are presented, focusing on the multi transistor amplifier modules delivering a power in the 0.5 to 1.5 kW range, the transmission line combiner system combining up to 150 amplifier modules, the monitoring of the rf power flow in the system and other relevant performance parameters, as well as the heat exchanger concept and the digital amplifier control system.
DESY Zeuthen, Zeuthen
DESY, Hamburg
The European XFEL, an X-ray free electron laser, is planned as an European project with a strong connection to the DESY research center in Hamburg. The LINAC of the XFEL incorporates 27 RF stations, which supply the RF power required by the superconducting cavities. In order to generate the RF power (1.3 GHz, 10MW pulses) HV pulse modulators are required. Each modulator has to supply 12kV pulses at 1.6kA for 1.5ms pulse duration and at 10Hz nominal repetition rate. The repetition rate can be increased to 30Hz at shorter pulse duration. Although extensive experience exists from the test facilities FLASH and PITZ (DESY Hamburg and Zeuthen sites) a dedicated modulator test stand has been setup to test and investigate additional new modulator prototypes developed by different companies. The results of these tests and the experience gained with the RF-stations at PITZ and FLASH will be an important criterium for the decision on the final layout and choice of vendor. An overview of the Modulator Test Facility at DESY will be presented. The first of two prototypes was delivered in July 2008 and started its operation in October. First test results of this prototype will be presented.
Diversified Technologies, Inc., Bedford, Massachusetts
Funding: U.S. Department of Energy SBIR Program
Constructing and supporting a wide range of RF amplifiers for research accelerators at is costly at present. This is because amplifiers to date have been designed for a single application, and have little commonality in their design and control interfaces. Diversified Technologies, Inc. (DTI) is developing a modular RF amplifier design for a wide range of amplifier requirements. Amplifiers built on this model have common design, controls, and spares, independent of frequency or power. The amplifier design combines a solid-state RF driver, power conditioning, and controls with a high-power vacuum electronic device, giving high performance at a low cost. In this paper, DTI will describe results of the first implementation of the amplifier, which delivers 20 kW CW at 704 MHz.
KEK, Ibaraki
The super-conducting RF test facility (STF) at KEK has been functional since 2005, and the STF phase-I, which involves the testing of a cryomodule with four superconducting cavities, was performed at the end of 2008. In this test, intense study of the power distribution system for the possible linear collider scheme was performed. Linear power distribution and tree-like distribution were compared and also the effects of eliminating circulator are studied. Current status of RF source of KEK STF are reported.
LBNL, Berkeley, California
UCB, Berkeley, California
Funding: This work was supported by the Director, Office of Science, Office of High Energy and Nuclear Physics, Division of Nuclear Physics of the US Department of Energy under Contract No. DE-AC02-05CH11231.
A RF system of 500W - 10.75 to 12.75 GHz was designed and integrated into the Advanced Electron Cyclotron Resonance (AECR) ion source of the 88-inch Cyclotron at Lawrence Berkeley National Laboratory. The AECR produces ion beams for the Cyclotron giving large flexibility of ion species and charge states. The broadband frequency of a Traveling Wave Tube (TWT) allows modifying the shape of the annular ellipsoidal-shaped volume that couples and heats the plasma. Details of the RF source and Automatic Gain Control Unit designs for the TWT and integration with the AECR source are provided.
Nano, Moscow
RAS/INR, Moscow
Solid State High Power RF System is proposed for XFEL and ILC. It includes individual RF power supply for each SC cavity and common control system. Each RF power supply includes Solid State Generator, circulator and Q-tuner. Triggering, synchronization, output power and phase of each Solid State Generator are controlled from the common control system through fiber-optic lines. Main parameters of Solid State Generator are: frequency 1.3Â GHz, peak power 128 kW, pulse length 1.4 msec, repetition rate 10 Hz, average power 1.8 kW, CW power 2.5 kW. Advantages of Solid State High Power RF System are: simple triggering, synchronization, output power and phase adjustment for all cavities separately, operation both in pulse and in CW modes, unlimited lifetime, no high voltage, no oil-tank, compactness.
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
EMMA is a prototype non-scaling FFAG that requires a demanding RF system. Production for the final RF system is due for completion in Spring 09 and testing of the combined hardware has taken place. This paper describes the high power verification tests of the IOT transmitter, waveguide distribution, RF cavity and LLRF control system.
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
The Muon Ionisation Cooling Experiment (MICE) at the Rutherford Appleton Laboratory uses normal conducting copper cavities to re-accelerate a muon beam after it has been retarded by liquid hydrogen absorbers. Each cavity operates at 200MHz and requires 1MW of RF power in a 1ms pulse at a repetition rate of 1Hz. In order to provide this power, a Thales TH116 triode, driven by a Burle 4616 tetrode is used, with each amplifier chain providing ~2.5MW. This power is then split between 2 cavities. The complete MICE RF system is described, including details of the low level RF, the power amplifiers and the coaxial power distribution system. Testing of the amplifier chain, power supplies and low level RF is described.
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
EMMA (Electron Model for Many Applications) is a non-scaling Fixed Field Accelerating Gradient (NS-FFAG) accelerator presently in the process of being built at Daresbury Laboratory as a proof of principle demonstrator for proton/carbon therapy application. Its aim is to take an injected beam from ALICE (Accelerators and Lasers in Combined Experiments) at 10MeV and accelerate it to 20MeV, so that the characteristics of NS-FFAGs can be studied. The beam is to be accelerated by 19 identical 1.3GHz RF cavities, which each need to provide the same accelerating voltage to the beam. The initial design stage of the RF system design has been completed, utilising three commercial suppliers of the major RF sub-system components.
Thomson Broadcast & Multimedia AG, Turgi
DESY, Hamburg
DESY Zeuthen, Zeuthen
The European XFEL project at DESY in Germany requires 27 RF stations capable of 10 MW RF power each. Each RF station needs one high voltage modulator that generates pulses up to 12 kV and 2 kA with a duration of 1.7 ms and a nominal repetition rate of 10 Hz. DESY decided to investigate new modulator prototypes and Thomson has been awarded to design and build one of these prototype modulators. The Thomson modulator is based on the pulse step modulator (PSM) principle. This technology allows the regulation of the pulse voltage during the pulses and by this achieving a good flatness. In addition to the common PSM technology this modulator design includes additional features. The first one is a constant power regulation system in order to prevent a 10 Hz loading of the mains. The second one is the extension of a part of the system to allow 2-quadrant mode in order to demagnetise the core of the pulse transformer between the pulses. The modulator has been delivered to DESY in July 2008 and is under testing at the modulator test facility in Zeuthen. The paper will give a detailed overview on the system and shows the results of the factory testing and of the testing at DESY.
CLS, Saskatoon, Saskatchewan
Upgrades to the orbit control system at the Canadian Light Source (CLS) have resulted in increased beam stability and reproducibility. These upgrades include improving position information from the beam position monitors (BPMs) by modifying the data acquisition algorithm and switching to a real-time operating system. Beam motion has been reduced to an RMS deviation of less than 1 micron in both planes. Limiting the maximum corrector step has allowed the use of all singular values when inverting the BPM response matrix, resulting in much better orbit reproducibility. As well, improved lookup tables have been developed to compensate for the effects of changing undulator gaps and polarizations. Presently, work is underway to develop fast orbit correction with rates up to 100 Hz. Fast orbit correction will further reduce the residual perturbations caused by undulator activity and will allow fast ramping of superconducting wigglers.
LSU/CAMD, Baton Rouge, Louisiana
To control the emittance coupling in the CAMD Light Source, new power supplies have been constructed which adjust the currents in the individual coils of the normal lattice sextupoles, thereby creating skew quadrupole fields. The new power supplies add or subtract current through the pre-energized coils. Performance contributing factors include a summing network with a temperature coefficient less than 1ppm/°C, a water cooled resistive shunt, and linear optical signal isolation. High density & modularity control boards and water cooled power cards are mounted as pull-out units in a 19” rack. Active limiters and fault indicators can provide reliability and portability to higher power designs. The use of these skew quadrupoles in controlling and minimizing the emittance coupling is presented.
ASCo, Clayton, Victoria
Argonne National Laboratory, Office of Naval Research Project, Argonne
Monash University, Faculty of Science, Victoria
SLAC, Menlo Park, California
This paper describes the implementation of a neural network hybrid controller for energy stabilization at the Australian Synchrotron Linac. The structure of the controller consists of a neural network (NNET) feed forward control, augmented by a conventional Proportional-Integral (PI) feedback controller to ensure stability of the system. The system is provided with past states of the machine in order to predict its future state, and therefore apply appropriate feed forward control. The NNET is able to cancel multiple frequency jitter in real-time. When it is not performing optimally due to jitter changes, the system can successfully be augmented by the PI controller to attenuate the remaining perturbations.
DESY, Hamburg
WTM, Hamburg
This poster describes the organizational structures and processes which were established for coordinating civil construction at the European XFEL. Local managements supervise the different construction sites in cooperation with a central team which manages the overall effort and provides general services (e.g. coordination, communication, safety, legal). Communication processes, workflows for reviewing, approving and distributing construction drawings and formalized change management have been defined and established. Reporting, cost management and controlling procedures have been put in place, as well as procedures for maintaining good public relations. All the processes are documented in a project handbook, and they are supported and optimized by IT systems, in particular the DESY Engineering Data Management System, DESY EDMS.
DESY Zeuthen, Zeuthen
DESY, Hamburg
A first prototype of a switching mirror has been designed, built and tested. With a repetition rate of up to 2.5 Hz the mirror is used to provide different beam lines with the Laser light produced by FLASH. The repetition accuracy is in the order of 1 um whereas the yawing is about 1 arcsec.
Kyoto IAE, Kyoto
KAERI, Daejon
UVSOR, Okazaki
The first laser amplification at a 12 micrometre mid-infrared free-electron laser (MIR-FEL) was observed at the Institute of Advanced Energy (IAE), Kyoto University in March 2008. A 25 MeV electron beam of 17 A peak current was used for the lasing experiment. FEL gain was estimated to be 16% from the exponential growth of the laser output signal. A beam loading compensation method with an RF amplitude control both in the thermionic RF gun and in the accelerator tube was used to extend the macropulse duration against the back bombardment effect in the gun. We also developed a feedforward RF phase control to stabilize the RF phase shifts which were originated with RF amplitude control. As a result FEL saturation was observed in May 2008. The estimated FEL gain was 33% with the electron beam of 5.5 microsecond macropulse duration by use of peak current of 33 A which was deduced from GENESIS simulation. A user beamline was designed and constructed. The laser characterization at the user station will be reported in the conference. Applications of the MIR-FEL at Kyoto University in the chemistry energy research will be presented as well.
Plansee Metall GmbH, Reutte
W.C. Heraeus GmbH, Materials Technology Dept., Hanau
Sheet material made of high-purity Niobium (Nb-RRR) is the key component for future linear accelerators based on the superconducting radio-frequency technology. To be prepared for large production scale quantities, which are demanded for the upcoming projects like XFEL and ILC respectively, W.C. Heraeus (D) and Plansee SE (A) joined there competencies in the field of Nb-RRR. In 2007 the qualification procedure as material supplier for the XFEL project could be successfully finished and a complete product and technology package for products made of Nb-RRR was established. Based on the combination of the high expertise and long-term experience in electron beam melting of different Nb-RRR qualities; the knowledge and availability of various processing technologies for manufacturing of semi-finished and ready to assemble components; and the unique analytical capabilities for advanced quality control along the process chain customized product solutions can be realized for the accelerator industry. Beside a general overview about the production capabilities a strategy for installation of a Quality-Assurance-Management system for large production scale quantities are presented.
KAERI, Daejon
Kyungpook National University, Daegu
KIRAMS, Seoul
Funding: This work was perfomed as a part of the Proton Engineering Frontier Project and supported by the ministry of Education, Science and Technology of Korea.
A prototype LEPT(Low Energy Proton Therapy) system was developed and established at the MC-50 cyclotron in 2007. Some of the users of the PEFP (Proton Engineering Frontier Project) has been requiring a irradiation system for in-vivo experiments for the beam utilization in the fieds of medical and biological sciences. We are studying on the possibility of in-vivo experiments the prototype LEPT system. The LEPT system consists of collimators, range shifter, modulator for SOBP, dose meaurement system, etc. The energy and current from the cyclotron was 45 MeV and a few nA. For the in-vivo experiments accurate control of dose rate and penetration depth range is essential. The other important issue is how we can control the irradiation area and depth with high uniform dose distribution. We investigated the dose rate and uniformity of dose distribution inside the sample using PMMA and water phantom. The dose was measured by using ionization chamber and GAF films. The dose rate was 0.2~1Gy/sec and the penetration depth was 10~15 mm. The further studies using small animals using this LEPT system will be done by the users.
NIRS, Chiba-shi
AEC, Chiba
A 3D scanning method gated with patient's respiration has been developed for the HIMAC new treatment facility. In the scanning irradiation, the RF-KO slow-extraction method has been used, because of the quick response to beam on/off from the synchrotron. However, a small amount of beam remained just inside the separatrix is extracted just before turning on the transverse RF field, which brings the extra dose. We proposed to apply another transverse RF-frequency component matched with the betatron frequency of the particles in the vicinity of the stopband, in addition to the original transverse RF field for the RF-KO slow-extraction. Using the proposed method, the particles just inside the separatrix, which cause the extra dose, can be selectively extracted during the irradiation; as a result, the extra dose can also be reduced. The validity of this approach has been verified by the simulation and the measurement with the non-distractive 2D beam profile monitor. We will report the result of this approach.
LANL, Los Alamos, New Mexico
Funding: Work performed under the auspices of the U.S. Department of Energy, under contract W-7405-ENG-36.
The WNR facility at LANSCE is preparing for a set of proton induced cross section measurements in support of the LANL Isotope Production Program. To determine the best way to produce particular isotopes, it is necessary to measure the production rate’s energy dependence. The first measurements will use a 197-MeV proton beam, which prompted recovery of the facility’s ability to transport multiple energy proton beams simultaneously to different experimental areas to ensure that an 800-MeV beam is available for Proton Radiography or Ultra-Cold Neutron experiments while a sample is irradiated with a lower energy beam for the cross section measurements. The ability to change the beam energy pulse-to-pulse was built into the original accelerator controls, but the multiple energy controls were unused for over a decade and the system was re-commissioned for this effort. These experiments form part of an effort to establish a capability for the measurement of cross sections in the 197 to 800 MeV energy range. The experiments are expected to provide the needed data for activities that may develop into a unique isotope production capability to compliment the existing 100-MeV IPF facility.
NSRRC, Hsinchu
A low run-out rotating sample stage is under development to realize a precise resolution within 30 nm on the horizontal plane for the end-station of transmission X-ray microscope (TXM) at NSRRC. The main assembly consists of a commercial rotation stage with run-out less than 1 μm, six capacitive sensors, one master ball, one flat and a horizontal adjusting stage. Error sources (including the profile of the master ball, run-out of the master ball in horizontal and vertical directions, flat plate) are separated from stage and the sensor readings can be down to the nanometer level. A feedback method is proposed to compensate the systematic errors and keeps the samples with little run-out and axial motion in the level of several tens nanometer. The details and tests of the rotation stage are presented in this paper.
CERN, Geneva
Following a series of injection tests, the first attempts to pass beam around both directions of the LHC were successful and led rapidly to circulating beam in the counter clockwise direction (beam 2) and many turns of beam 1. Unfortunately the beam commissioning was curtailed by the incident in sector 34. However, measurements performed during this first commissioning period should that the magnet model of the machine had delivered optics close to nominal, and also very good performance of beam instrumentation and supporting software. Details of the machine set-up and the commissioning procedures are detailed. The measurements performed and the key results from this period are described.
Fermilab, Batavia
MSU, East Lansing, Michigan
TRIUMF, Vancouver
PAC, Batavia, Illinois
UCR, Riverside, California
The quest for higher beam power and duty factor and precisely controlled beams at reasonable cost has generated world-wide interest in Fixed-field Alternating Gradient accelerators (FFAGs). A new concept in non-scaling FFAGs to stabilize the betatron tune is under development. The emphasis to date has been on electron and proton accelerators, yet many facilities utilize H- front ends. This concept naturally extends to H- FFAGs and under conditions of rapid acceleration, the FFAG functions essentially as a recirculating linac with a common-aperture arc. As such it may be suitable for replacement of aging H- linac sections. For a slow acceleration cycle, an H- FFAG machine can exploit H- techniques to control extraction and intensity, and represents an innovation in proton therapy accelerators. Prototype RF and magnet component design have been initiated. For ten-turn acceleration, the rf cavities in a 10-100 MeV FFAG cannot be re-phased on the revolution time scale, and local adjustment of the pathlength is the proposed approach. For slow acceleration, broad-band, low-frequency rf can be applied. The basic optics and components for such FFAGs are presented.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
J-PARC, KEK & JAEA, Ibaraki-ken
The painting injection of the 3-GeV RCS in J-PARC has been tested since May in 2008. The shift bump-magnets, which give a constant bump field in a horizontal plane during injection, comprise four magnets connected in series. However, the total integrated magnetic field over the four magnets is not zero because of the magnetic field interferences with the neighboring quadrupole magnets. So the gap of each magnet was adjusted by inserting thin insulators into the splitting plane of the side yoke so that the field integration becomes zero. The thickness was determined experimentally. The closed orbit distortion due to the field imbalances was then confirmed to be less than 1 mm. Another four paint bump-magnets are also necessary to give time-dependent fields. They are connected to their own power supplies, separately. The excitation of each magnet is calibrated by using the beam so that the created bump orbit satisfies the position and inclination at the injection point, and there are no orbit distortions outside the injection area. As for a vertical plane, a vertical paint magnet is located pi-radian upstream of the injection point to control the vertical angle of the beam.
ANL, Argonne
Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The Circular Polarizing Undulator (CPU) had been used for about 10 years at the APS to generate X-rays with variable polarization (circular and linear) switching at rates up to 10 Hz. The CPU consists of two main coils with maximal currents 1600A (about 30kW power) and 400A (4kW power) and seven additional correcting coils. Aging and obsolescence of some of the CPU PS critical components resulted in deterioration of its performance and elevated maintenance. To resolve the issue and to comply with the new requirements for the beam stability at the APS storage ring, the new PS and control electronics for the CPU have been proposed. The new 8-channel Arbitrary Function Generator generating unique complex waveforms for the correctors to minimize orbit distortion during the main coils PS switching will also be discussed in this paper.
ANL, Argonne
Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The APS storage ring uses DC/DC converters to power the magnets. High resolution for current regulation is desired for future improvement. It is calculated that at least 20- to 21-bit digital pulse width modulation (DPWM) is required in the proposed digital control system. This paper proposes a digital control system that adopts a new DPWM topology to achieve 21-bit DPWM without gigahertz system clock. The proposed topology uses a combination of a field-programmable gate array (FPGA) and a serializer chip TLK2541 from TI. The FPGA calculates the desired PWM signals and sends them to the TLK2541 chip. Then, the TLK2541 generates corresponding high-resolution DPWM pulses. An FPGA development board has been used to develop a prototype system to verify the proposed DPWM generation topology. This paper discusses the circuit topology and the experiment results.
BNL, Upton, Long Island, New York
The Brookhaven AGS Main Magnet Power Supply is a thyristor control supply rated at 5.5KAmps, ±9KV. The peak magnet power is 50MW,which is fed from a motor/generator manufactured by Siemens. During rectify and invert operation, the P Bank power supplies are used. During the flattops the F Bank power supplies are used. The P Bank power supplies are fed from two 23MVA transformers and the F Bank power supplies are fed from two 5.3 MVA transformers. The fundamental frequency of the F Bank power supplies is 1440Hz while the P banks were 720Hz. It was very important to reduce the ripple during rectify to improve polarized proton operations. For this reason and also because the original transformers were 45 years old we replaced these transformers with new ones and we made the fundamental frequency of both P and F banks 1440 Hz. This paper will highlight the major hurdles that were involved during the installation of the new transformers. It will present waveforms while running at different power levels up to 6MW full load and show the transition from the F-Bank power supplies to the P-Banks and also show the improvements in ripple made on the P-Bank power supplies.
IHEP Beijing, Beijing
The 1.6GeV proton synchrotron proposed in the CSNS Project is a 25Hz rapid-cycling synchrotron (RCS) with 80MeV Linac. Beam power is aimed to 100kW at 1.6GeV. In this paper the designs of the prototype of DTL-Q power supply and the prototype of the resonant network with one mesh exciting in series will be introduced.
Fermilab, Batavia
Fermilab is in the process of upgrading its Booster Correction Element System to include full field correction element magnets to correct position and chromaticity throughout the booster cycle. From a reliability standpoint, it is important to limit both the maximum temperature and the repetitive temperature cycling of the silicon junctions of the switching elements. We will describe how we measured these parameters and the results of our measurements.
Fermilab, Batavia
Fermilab is in the process of upgrading its Booster Correction Element System to include full field correction element magnets to correct position and chromaticity throughout the booster cycle. This upgrade requires power supplies with maximum outputs of ±180V/±65A, with current bandwidths of 5kHz and with slew rates of min to max current in 1ms. For seamless operation around zero current and voltage, we use continuous switching on both sides of the bridge. Although the straightforward way of coordinating the switching on both sides of the bridge can be accomplished with one triangle timing wave and one voltage reference, we have found that using two triangle waves yields a switching coordination that effectively doubles the frequency of the differential ripple on the load and allows for better and cheaper filtering of the output ripple.
LBNL, Berkeley, California
Funding: This work was supported by the Director, Office of Science, U. S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Advanced Light Source (ALS) is a third generation synchrotron light source that has been operating since 1993 at Berkeley Lab. Recently, the ALS was upgraded to achieve Top-Off Mode, which allows injection of 1.9GeV electron beam into the Storage Ring approximately every 30 seconds. Modifications required for Top-Off operation included replacing the booster dipole and quadrupole magnet power supplies to increase the peak booster beam energy from 1.5GeV to 1.9GeV. Each new power supply was originally controlled by an analog controller that performs the current feedback loop and, in concert with other modules in the control chassis, determines the output of the ramped power supply. The new digital power supply controller performs the current feedback loop digitally to provide greater output stability and resolution. In addition, it provides remote monitoring of feedback loop signals, interlocks, and status signals, as well as remote control of the power supply operation via Ethernet. This paper will present the ALS Digital Power Supply Controller module requirements and design.
NSRRC, Hsinchu
The Agilient 6682A power supply is used as a dipole magnet power supply of Booster to storage ring (BTS) transport line, its output current stability is less than 100 ppm although specification is 1000 ppm. The performance of Agilient 6682A is quite good for TLS operational requirement but not suitable for less than 10 ppm output current stability general requirement of power supplies of TPS. Circuitry modification of Agilient 6682A to reach less than 10 ppm output current stability is hard to implement; but utilize analog programming function of Agilient 6682A with adding an external current control loop the output current stability of Agilient 6682A could be improved to less than 10 ppm.
SLAC, Menlo Park, California
Funding: Work supported by the U.S. Department of Energy under contract number DE-AC02-76SF00515
This paper will report on the test results of a prototype 1320 watt power module for a high availability power supply. The module will allow parallel operation for N+1 redundancy with hot swap capability. The two quadrant output of each module allows pairs of modules to provide a 4 quadrant (bipolar) operation. Each module employs a novel 4 FET buck regulator arranged in a bridge configuration. Each side of the bridge alternately conducts through a small saturable ferrite that limits the reverse current in the FET body diode during turn off. This allows hard switching of the FETs with low switching losses. The module is designed with over-rated components to provide high reliability and better then 97% efficiency at full load. The modules use a Microchip DSP for control, monitoring, and fault detection. The switching FETS are driven by PWM modules in the DSP at 60 Khz. A Dual CAN bus interface provides for low cost redundant control paths. The DSP will also provide current sharing between modules, synchronized switching, and soft start up for hot swapping. The input and output of each module have low resistance FETs to allow hot swapping and isolation of faulted units.
STFC/RAL/ISIS, Chilton, Didcot, Oxon
Funding: ISIS
The Extracted Proton beam line for the ISIS second target station has two 10 Hz pulsed magnet systems and a DC Septum magnet system which extract the protons from the existing 50 Hz beam line. The pulsed Kicker 1 magnet system deflects the beam 12.1 mrad, pulsed Kicker 2 deflects the beam 95 mrad and the DC Septum magnet system deflects the beam 307 mrad. This paper describes the topology, installation, testing and successful operation of each of the power supplies.
CERN, Geneva
The LHC injection tests and first turn beam commissioning took place in late summer 2008, after detailed and thorough preparation. The beam commissioning of the downstream sections of the SPS-to-LHC transfer lines and the LHC injection systems is described. The details of the aperture measurements in the injection regions are presented together with the performance of the injection related equipment. The measured injection stability is compared to the expectations. The operational issues encountered are discussed.
CERN, Geneva
After each beam dump in the LHC automatic post-operational checks are made to guarantee that the last beam dump has been executed correctly and that the system can be declared to be 'as good as new' before the next injection is allowed. The analysis scope comprises the kicker waveforms, redundancy in kicker generator signal paths and different beam instrumentation measurements. This paper describes the implementation and the operational experience of the internal and external post-operational checks of the LHC beam dumping system during the commissioning of the LHC without beam and during the first days of beam operation.
KEK, Tsukuba
Tokyo City University, Tokyo
NIRS, Chiba-shi
J-PARC (Japan Proton Accelerator Research Complex) is a new accelerator facility to produce MW-class high power proton beams at both 3GeV and 50GeV. The Main Ring (MR) of J-PARC can extract beams to the neutrino beam line and the slow extraction beam line for Hadron Experimental Facility. The slow extraction beam is used in various nuclear and particle physics experiments. A flat structure and low ripple noise are required for the spills of the slow extraction. We are developing the spill control system for the slow extraction beam. The spill control system consists of the extraction quadrupole magnets and feedback device. The extraction magnets consist of two kinds of quadrupole magnets, EQ (Extraction Q-magnet) which make flat beam and RQ (Ripple Q-magnet) which reject the high frequent ripple noise. The feedback system, which is using Digital Signal Processor (DSP), makes a ramping pattern for EQ and RQ from spill beam monitor. Here we report the construction status of the extraction magnets and the development of the feedback system.
SLAC, Menlo Park, California
BNL, Upton, Long Island, New York
Funding: Work supported by the US Department of Energy, Office of Basic Energy Sciences.
In the past, SPEAR3 has had typically 50 to 70% injection efficiency. Much of the lost injected beam hit the small gap vacuum chambers at the insertion devices. We are now implementing injection with photon beamline shutters open, so these losses create Bremsstrahlung down the photon beamlines, increasing radiation levels on the photon experimental floor. In this paper, we describe work done to better control the booster to SPEAR (BTS) transport line beam so as to reduce losses during injection. We have used new BTS BPM electronics to control the transport line trajectory. The trajectory response on these BPMs has been used to correct the BTS optics. We use turn-by-turn BPM readings of the injected beam in SPEAR to optimize the BTS trajectory in all six transverse and longitudinal coordinates. We use turn-by-turn profile measurements of the injected beam to verify the BTS optics correction. The stainless steel windows have been removed from the BTS vacuum system to reduce the transverse dimensions of the injected beam.
IHEP Beijing, Beijing
The prototype of pulsed power supply for injection painting bump magnets of CSNS/RCS is being developed. This pulsed power supply consists of IGBT H bridges in series and parallel. The pulse current of the prototype is 18000A, the voltage is about 3KV and the equivalent frequency is about 1MHz. This paper will introduce this prototype in detail.
DULY Research Inc., Rancho Palos Verdes, California
Marx modulators, operated by the solid-state switches of Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) or Insulated Gate Bipolar Transistors (IGBTs), offer an alternative to conventional high voltage modulators for rf power sources. They have the advantages of compact size, high-energy efficiency, high reliability, pulse width control and cost reduction. However, Marx modulators need a complex voltage compensation circuit if they are employed in long pulse applications such as the ILC project. We describe novel schemes to compensate the voltage droop of the Marx modulator and minimize the flattop fluctuation of the voltage pulse output through the utilization of inductances and the fast switching properties of solid-state switches. The feasibility of the schemes has been analyzed and relevant data will be presented.
Diversified Technologies, Inc., Bedford, Massachusetts
Funding: Funding by U.S. Department of Energy SBIR program.
Diversified Technologies, Inc. (DTI) has developed high power, solid-state Marx Bank modulators for a range of accelerators and colliders. We estimate the Marx topology can deliver equivalent performance to conventional designs, while reducing system costs by 25-50%. In this paper DTI will describe the application of Marx based technology to a long-pulse (140 kV, 160 A, 1.5 ms) modulator design focused on the International Linear Collider. The primary engineering challenge is minimizing the overall size and cost of the storage capacitors in the modulator. Unique choices in components and controls are needed, including the use of electrolytic capacitors. This paper will review recent progress in the development and testing of this long pulse Marx modulator built under a U.S. Department of Energy Phase II SBIR grant.
CERN, Geneva
The goal of the present CLIC Test Facility (CTF3) is to demonstrate the technical feasibility of specific key issues in the CLIC scheme. The extracted drive beam from the combiner ring (CR), of 35 A in magnitude and 140 ns duration, is sent to the new CLic EXperimental area (CLEX) facility. A Tail Clipper (TC) is required, in the CR to CLEX transfer line, to allow the duration of the extracted beam pulse to be adjusted. Fours sets of striplines are used for the tail clipper, each consisting of a pair of deflector plates driven to equal but opposite potential. The tail clipper kick must have a fast field rise-time, of not more than 5 ns, in order to minimize uncontrolled beam loss. High voltage MOSFET switches have been chosen to meet the demanding specifications for the semiconductor switches for the modulator of the tail clipper. This paper discusses the design of the modulator; measurement data obtained during testing and operation of the tail clipper is presented and analyzed.
LBNL, Berkeley, California
Funding: *Work supported by the Director, Office of Science, Office of Basic Energy Sciences, Materials Science and Engineering Division, of the Department of Energy under contract No. DE-AC02-05CH11231.
ALS is the 1.9GeV third generation synchrotron light source which has been operating since 1993 at Berkeley National Lab. Our team is now working on the design of a new RF power source (replacement of the existing 320kW klystron with 4 IOT’s). In the new design the existing conventional crow-bar klystron protection system will be replaced with a fast disconnect switch. The switch will be constructed out of 16 high-voltage IGBT’s connected in series equipped with static and dynamic balancing system. The main advantage of using this new technology is faster action and virtually no stress for the components of the high voltage power supply. This paper will describe the hardware design process and the test results of the prototype switch unit.
SLAC, Menlo Park, California
Funding: Work supported by the Department of Energy under contract No. DE-AC02-76SF00515.
The design and installation of the Linac Coherent Light Source* at SLAC National Accelerator Laboratory has included the development of a kicker system for selective beam bunch dumping. The kicker is based on an LC resonant topology formed by the 50 uF energy storage capacitor and the 64 uH air core magnet load and has a sinusoidal pulse period of 400us. The maximum magnet current is 500 A. The circuit is weakly damped, allowing most of the magnet energy to be recovered in the energy storage capacitor. The kicker runs at a repetition rate of 120Hz. A PLC-based control system provides remote control and monitoring of the kicker via EPICS protocol. Fast timing and interlock signals are converted by discrete peak-detect and sample-hold circuits into DC signals that can be processed by the PLC. The design and experimental characterization of the systems is presented.
*http://ssrl.slac.stanford.edu/lcls/
SLAC, Menlo Park, California
Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515
A program is underway at SLAC to develop a Marx-topology klystron modulator for the International Linear Collider* project. It is envisioned as a smaller, lower cost, and higher reliability alternative to the bouncer-topology baseline design. The application requires 120 kV (±0.5%), 140 A, 1.6 ms pulses at a rate of 5 Hz. The Marx constructs the high voltage pulse without an output transformer, large at these parameters, by instead combining a number of lower voltage cells in series. The modularity of the Marx topology is further exploited to achieve a redundant, high-availability design. The ILC Marx employs solid state elements; IGBTs and diodes, to control the charge, discharge and isolation of the cells. The SLAC designs are oil-free; air is used for high voltage insulation and cooling. The first generation prototype, P1, is undergoing life testing. Development of a second generation prototype, P2, is underway. Status updates for both prototypes will be presented.
*ILC Reference Design Report, http://www.linearcollider.org/cms/?pid=1000437
SLAC, Menlo Park, California
ORNL, Oak Ridge, Tennessee
Funding: Work supported by the Department of Energy under contract No. DE-AC02-76SF00515.
The 1-MW High Voltage Converter Modulators* have operated in excess of 250,000 hours at the Spallation Neutron Source. Increased demands on the accelerator performance require increased modulator reliability. An effort is underway at SLAC National Accelerator Laboratory to redesign the modulator H-bridge switch plate with the goals of increasing reliability and performance**. The major difference between the SLAC design and the existing design is the use of press-pack IGBTs. Compared to other packaging options, these IGBTs have been shown to have increased performance in pulsed-power applications, have increased cooling capability, and do not fragment and disassemble during a fault event. An overview of the SLAC switch plate redesign is presented. Design steps including electrical modeling of the modulator and H-bridge, development of an integrated IGBT clamping mechanism, and heat sink performance validation are discussed. Experimental results will be presented comparing electrical performance of the SLAC switch plate to the existing switchplate under normal and fault conditions.
*W. A. Reass, et al., “Design, Status, and First Operations of the Spallation Neutron Source Polyphase Â
”, PAC, 2003
**M.A. Kemp, et al., “Next Generation IGBT Switch Plate Â
,” LINAC, 2008.
SLAC, Menlo Park, California
ORNL, Oak Ridge, Tennessee
Funding: Work supported by the Department of Energy under contract No. DE-AC02-76SF00515.
SLAC National Accelerator Laboratory is developing a next generation H-bridge switch plate*, a critical component of the SNS High Voltage Converter Modulators**. As part of that effort, a new IGBT gate driver has been developed. The drivers are an integral part of the switch plate, which are essential to ensuring fault-tolerant, high-performance operation of the modulator. The redesigned drivers improve upon the existing gate drives in several ways. The new gate driver has improved fault detection and suppression capabilities; suppression of shoot-through and over-voltage conditions, monitoring of excess di/dt and Vce,sat, and redundant power isolation are some of the added features. Also, triggering insertion delay is reduced by a factor of four compared to the existing driver. This presentation details the design and performance of the new IGBT gate driver. A detailed schematic and description of the construction are included. Operation of the fast over-current detection circuits, active IGBT over-voltage protection circuit, shoot-through prevention and control power isolation breakdown detection circuit are discussed.
*W. A. Reass, et al., “Design, Status, and First Operations of the Spallation Neutron Source Polyphase Â
”, PAC, 2003
**M.A. Kemp, et al., “Next Generation IGBT Switch Plate Â
,” LINAC, 2008.
ORNL, Oak Ridge, Tennessee
Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy
Latest technologies promise new control systems user interface features and greater interoperability of applications. New developments using Java and Eclipse aim to unify diverse control systems and make communication between applications seamless. Web based user interfaces can improve portability and remote access. Modern programming tool improve efficiency, support testing and facilitate shared code. This talk will discuss new developments aimed at improving control system interfaces and their development environment.
CERN, Geneva
Virtually all modern accelerator control systems are nowadays based on commercial-off-the-shelf products (VME crates, PLCs, SCADA systems, etc.), on Windows or Linux PCs, and on communication infrastructures using Ethernet and TCP/IP. Despite the benefits coming with this (r)evolution, these "modern" control systems and infrastructures usually completely lack adequate levels of robustness, resilience and security. Even worse, new threats are inherited, too: Worms and viruses spread within seconds via the Ethernet cable, and attackers are becoming interested in breaking into control systems. This talk will discuss the initial security risks, what precautions are needed to protect control systems against cyber threats and how to provide a secure environment without sacrificing operability.
BNL, Upton, Long Island, New York
Overview of the main factors determining machine availability. Comparison of availability issues and strategy for high energy colliders and accelerators, synchrotron light sources, and spallation neutron sources. Description of how machines can be designed for high availability and systems for high reliability.
Cosylab, Ljubljana
Accelerators are designed to be in operation for several decades, and frequently even their construction alone takes a decade or more. Given the rapid rate of obsolescence of information technologies, it becomes a challenge how to choose the technologies that would stand the test of time, or at least make long-term support manageable. In this article, we focus on middleware: the glue that keeps inherently heterogeneous control system platforms able to interoperate with each another. Modern and less-modern middlewares, such as Internet Communication Environment (ICE), Common Object Request Broker Architecture (CORBA), Microsoft Windows Communications Foundation (WCF) are presented, and contrasted with more domain-specific middleware, such as the Experimental Physics and Industrial Control System (EPICS). We argue that whichever middleware technology is used, it is advisable to abstract it with simple, domain-specific APIs, whose implementation can change as the evolving performance requirements push the initial middleware choice beyond its limits of applicability.
BESSY GmbH, Berlin
HZB, Berlin
The Metrology Light Source (MLS) is in user operation since April 2008 working at energies ranging from {10}5 MeV up to 630 MeV, operating currents from a single electron up to 200 mA and different values for the momentum compaction factor. In parallel to machine commissioning, an automated finite state machine has been developed. This code knows, controls and coordinates a broad manifold of machine states and meanwhile has been evolved to an automated operator acting by itself on demand of a few high level commands. Actions range from plain device I/O to complex transactions including filesystem operations and multiple device I/O. The aim is to always keep machine and control system in a well-defined state. We describe the program and report on the experience with the automated operation using this application.
LBNL, Berkeley, California
Traditional rf processing systems have involved heterodyned rf processing based on mixing a Local Oscillator to up and down convert rf signals through a baseband I/Q or Mag/Phase processing channel. These systems were traditionally custom engineered for each accelerator application. Recent technical developments in rf processing and the development of sufficiently fast reprogrammable digital processing functions lead to development of general-purpose rf processing functions which can incorporate a mix of heterodyned and direct digital down/up-converted processing ("software radio"). This general-purpose approach allows one design of hardware to be applicable to many rf processing tasks, where the firmware and software in the programmable functions define the application. An example design, with applications to linac LLRF control loops and electro-optic timing reference stabilization is presented.
Fermilab, Batavia
Funding: FRA
Fermilab’s High Intensity Neutrino Source (HINS), the 325 MHz low energy section of Project X consists of an RFQ, 18 copper cavities and a section of superconducting spoke resonator cavities, all driven by a single 2.5 MW klystron. Each cavity has a high power ferrite vector modulator which provides individual RF power control. This paper proposes a scheme that optimizes RF drive and vector modulator control. The different gradients, acceleration phase angles, unloaded Q’s and beam loading are taken into account to optimize the cavities detuning angles, forward power, and loaded Q’s. This scheme makes an efficient use of the klystron’s high bandwidth ability to modulate the forward power, hence minimizing the burden on the high power vector modulator during the RF pulse. The proposed method is explained in details, a parameter sensitivity analysis is performed and the impact on the total power consumption for the RF station is calculated.
BARC, Trombay, Mumbai
Indian Institute of Technology Bombay, Mumbai
TIFR, Mumbai
As a first step towards development in digital domain, a computer model of a self excited loop (SEL) has been created using MATLAB/SIMULINK. The behaviour of a resonator and a power amplifier combination has been approximated using two first-order differential equations. The square of the amplitude of the RF field in the resonator acts as a driving force for the motion of mechanical modes of the resonator, which are individually represented as second order systems. A key element is the limiter, which has been modelled as a feedback loop, to achieve constant output amplitude. The model has been created in the I-Q domain for computational efficiency and close correspondence with actual implementation. To study the field stabilisation, proportional amplitude and phase feedback loops have been appended to the model of the SEL. In this paper we discuss the details of the model and results from simulation. Initial experimental results are also presented.
KEK, Ibaraki
Future accelerators require a high resolution beam profile monitor that measures the beam non-destructively and works at high beam intensity. Laser based beam monitors can be the solution. It uses a focused laser beam to scan the electron beam while detecting the Compton scattered photon. Accelerator Test Facility at KEK has been developing various types of Laser Wire monitors. CW laser wire with build-up optical cavity has been used to measure the small emittance beam at the damping ring. Pulsed laser wire has been developed to measure a small focused beam at the extraction line. Performance of these systems will be presented.
IHEP Beijing, Beijing
PKU/IHIP, Beijing
CIAE, Beijing
A high-duty factor proton RFQ accelerator has been constructed at IHEP, Beijing for the basic study of Accelerator Driven Subcritical System. The ADS basic study is supported by a national program for nuclear waste transmutation which is regarded essential for the rapid development of nuclear power plants in China. In the initial commissioning of the 3.5MeV RFQ with an ECR ion source showed a nice performance with a transmission rate about 93% with an output beam of 46mA. The 352MHz RFQ is design for CW operation with the RF power source from LEP-II of CERN. This paper presents the beam commissioning and recent progress in high-duty factor operation from 7% to 15%.
LBNL, Berkeley, California
Funding: Supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
ALS has been upgraded by adding Top-Off Mode, a new mode of operation to the existing modes of Fill and Stored Beam. The Top-Off Mode permits injection of 1.9GeV electron beam into the Storage Ring, with the safety shutters open, once certain strict conditions are met and maintained. Top-Off Mode enables User operation without an interruption caused by mode switching between the Stored Beam Mode when safety shutters are open, to the Fill Mode with the safety shutters closed and back. The conditions necessary to permit Top-Off Mode are; stored beam is present, the energies are matched between the injector and storage ring, a select set of storage ring lattice magnets are operating at the correct current levels, and radiation losses are minimized. If certain combinations of these conditions are not met, a potentially dangerous condition of injecting electrons down a users beam line can exist. Therefore a system of mode control, energy match, lattice match and stored beam interlocks are needed to control the injected beam prohibiting potentially dangerous conditions. In this paper we will present the Top-Off Mode Beam Interlock system requirements, design, and operational parameters.
Imperial College of Science and Technology, London
Imperial College of Science and Technology, Department of Physics, London
Cockcroft Institute, Lancaster University, Lancaster
The proposed Muon Cooling System for the Neutrino Factory operates with high accelerating gradient in the presence of magnetic field. This can significantly increase the risk of RF breakdown. Field Emission is the most frequently encountered RF breakdown that occurs at sites with local electromagnetic field enhancement. Surface defects can be considered as possible emission sites. Upon Impact, generally the majority of electron’s energy is converted into stress and heat. In return, the damage inflicted can create additional emission sites. This paper presents the work under way, which aims to model certain physical phenomena during both emission and impact of electrons. The three-dimensional field profile of an 805 MHz pill-box cavity is modelled by Comsol Multuphysics. A tracking code written in-house is employed to track particles, providing sufficient data such as energy and speed at small time steps. This would allow the study of local heat transfer, applied surface stresses and secondary electron yield upon impact with the RF surface. In addition, the effects of externally applied magnetic field on electron’s behaviour are to be investigated.
JAEA/J-PARC, Tokai-mura
KEK, Ibaraki
KEK/JAEA, Ibaraki-Ken
J-PARC consists of a 181 MeV linac, a 3GeV Rapid Cycling Synchrotron (RCS) and a 50 GeV Synchrotron (MR). The RCS is designed to accelerate a high intensity proton beam. One of the key issues of the RCS RF system is how to achieve the very high accelerating field gradient of more than 20kV/m. This is impossible with conventional ferrite-loaded cavities. We reach this goal by the development of Magnetic Alloy (MA) core loaded RF cavities. We installed 10 RF cavities in the RCS tunnel on May 2007. The RCS beam commissioning was started on September 2007 and we successfully accelerated a proton beam up to 3GeV on October 2007. We also employed MA cores for MR RF cavities and use a cut core configuration to adjust the Q-value. The MR beam commissioning was started on May 2008. We didn't have any trouble caused by the MA cores during operation. We measured the impedance of the RF cavities several times at the shutdown periods. We show the results of impedance measurements. From these results, we can make an assumption about the core condition.
LAL, Orsay
INFN/LNL, Legnaro (PD)
LAL-Orsay is developing an important effort on R&D studies on RF power couplers. One of the most critical components of those devices is the ceramic RF window that allows the power flux to be injected in the coaxial line. The presence of a dielectric window on a high power RF line has a strong influence on the multipactor phenomena. To reduce this effect, the decrease the secondary emission yield (SEY)of the ceramic window is needed. Due to its low SEY coefficient, TiN coating is used for this goal. In this framework, a TiN sputtering bench has been developed in LAL. The reactive sputtering of TiN needs the optimisation of gas flow parameters and electrical one, to obtain stoechiometric deposit. XRD analysis was performed to control the film composition and stoechiometry. Measurements point out how the Nitrogen vacancy on the film can be controlled acting on the N2 flow. In addition, the coating thickness must be optimized so that the TiN coating effectively reduces the SEY coefficient but does not cause excessive heating, due to ohmic loss. For this purposes, multipactor level breakdown and resistance measurements were done for different deposit thickness.
University of Tennessee, Knoxville, Tennessee
ORNL RAD, Oak Ridge, Tennessee
ORNL, Oak Ridge, Tennessee
RF properties of twisted waveguide structures were investigated to show that slow-wave accelerating fields can be excited and used for acceleration of particle at various velocities lately. To build a practical accelerating cavity structure using the twisted waveguide, more development work was needed: cavity structure tuning, end wall effect of the structures, incorporating beam pipes and input power coupler, and HOM damping, etc. In this paper, the practical aspects of the designs to make more complete accelerating structures are discussed with the results of computer simulations.
SLAC, Menlo Park, California
Funding: Work supported by the DOE under contract DE-AC02-76SF00515
A new facility to clean, assemble, bake and rf process TTF3-style power couplers has been completed and is in operation at SLAC. This facility includes a class-10 cleanroom, bake station and an L-band source capable of producing up to 4 MW pulses. This paper describes the facility, test results from processing pairs of couplers that will be used in cryomodules at FNAL, and efforts to simplify the design and manufacturing of the couplers for large scale use at ILC. Also, tests of the couplers to explore their power limits for use in an FNAL superconducting proton linac are presented.
ELETTRA, Basovizza
Funding: The work was supported in part by the Italian Ministry of University and Research under grants FIRB-RBAP045JF2 and FIRB-RBAP06AWK3
FERMI@Elettra is a seeded FEL user facility under construction at Sincrotrone Trieste, Italy. The linac is based on S-band normal conducting technology. It will use the accelerating sections of the original Elettra linac injector, seven sections received from CERN after LIL decommissioning and two additional sections to be constructed for a total number of 18 S-band accelerating structures. Installation of the machine is presently being carried on. This paper will provide a summary of the requirements of the different parts of the S-band RF system and of the options for a possible upgrade path both in energy and reliability. The ongoing activities on the main subassemblies, in particular regarding the tests and the installation work, are also presented.
INFN/LASA, Segrate (MI)
DESY, Hamburg
Cavity tuners are needed to precisely tune the resonant frequency of TESLA SC cavities for European XFEL linac. Although several units of the currently used device, originally designed at Saclay for TTF and then developed at DESY, have been manufactured and tested so far, a permanent installation like the XFEL poses higher requirements in terms of reliability and reproducibility. XFEL indeed requires about {10}00 tuners to be produced in a relatively short time and then to simultaneously work in cryogenic environment, each of them being equipped with a stepper motor driving unit and two piezoelectric actuators. In this frame, an acceptance test procedure, here presented, has been studied, its main goal being the cross-check of issues affecting reliability: installation, mechanical coupling of active elements to cavity, motor and fast actuators functionality. An electronic equipment has been developed for driving signals, sensors and data management, specifically aiming toward an automatic and user-friendly routine in view of a large scale application. The procedure has been then applied for calibration purposes of a sample cavity assembly, the experimental results are also presented.
INFN/LASA, Segrate (MI)
Funding: Work partially supported by the FP6 EU programs EUROTRANS (Contract FI6KW-CT-2004-516520) and CARE/HIPPI (Contract RII3-CT-2003-506395).
The two TRASCO elliptical superconducting cavities for low energy (100-200 MeV) protons have been completed with equipping them with cold tuner and a magnetic shield internal to the helium tank. One of the two structures is now available for significative tests of Lorentz Force Detuning control of these low beta structures under pulsed conditions for future high intensity linac programs, as SPL or the ESS. The second structure will be integrated in a single cavity cryomodule under fabrication for the prototypical activities of the EUROTRANS program for nuclear waste trasmutation in accelerator driven systems.
KAERI, Daejon
Funding: This work is supported by the Ministry of Education, Science and Technology of Korea.
A superconducting radio frequency (SRF) cavity with a geometrical beta of 0.42 has been designed to accelerate a proton beam after 100 MeV at 700 MHz for an extended project of Proton Engineering Frontier Project (PEFP). In order to confirm the RF and mechanical properties of the cavity, and to produce documentation for a procurement and quality control for an industrial manufacture of the cavities, two prototype copper cavities have been produced, tuned and tested. In this paper, the copper cavity’s production, tuning and testing are introduced. The testing results show that the low-beta cavity and its tuning system can work as we design.
Muons, Inc, Batavia
JLAB, Newport News, Virginia
Funding: Supported in part by DOE SBIR grant DE-FG02-08ER85171 Supported in part by USDOE Contract DE-AC05-84-ER-40150
There are over 35 coupler designs for SRF cavities ranging in frequency from 325 to 1500 MHz. Two-thirds of these designs are coaxial couplers using disk or cylindrical ceramics in various combinations and configurations. While it is well known that dielectric losses go down by several orders of magnitude at cryogenic temperatures, it not well known that the thermal conductivity also goes down, and it is the ratio of thermal conductivity to loss tangent (SRF ceramic Quality Factor) and ceramic volume which will determine the heat load of any given design. We describe a novel robust co-axial SRF coupler design which uses compressed window technology. This technology will allow the use of highly thermally conductive materials for cryogenic windows. The mechanical designs will fit into standard-sized ConFlat® flanges for ease of assembly. Two windows will be used in a coaxial line. The distance between the windows is adjusted to cancel their reflections so that the same window can be used in many different applications at various frequencies.
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
Cockcroft Institute, Lancaster University, Lancaster
The ILC crab cavities require very tight phase control in order to operate within the ILC parameters. In order to verify that the phase control system met the design tolerances, two single-cell niobium 3.9GHz superconducting dipole-mode cavities were tested in a liquid helium cryostat. The preparation of the cavities, design of the testing apparatus and performance of the phase control system are described in this paper.
BARC, Trombay, Mumbai
Indian Institute of Technology Bombay, Mumbai
CERN, Geneva
An RF system model has been created for the CERN Linac2 Tanks. RF systems in this linac have both single and double feed architectures. The main elements of these systems are: RF power amplifier, main resonator, feed-line and the amplitude and phase feedback loops. The model of the composite system is derived by suitably concatenating the models of these individual sub-systems. For computational efficiency the modeling has been carried out in the base band. The signals are expressed in in-phase - quadrature domain, where the response of the resonator is expressed using two linear differential equations, making it valid for large signal conditions. MATLAB/SIMULINK has been used for creating the model. The model has been found useful in predicting the system behaviour, especially during the transients. In the paper we present the details of the model, highlighting the methodology, which could be easily extended to multiple feed RF systems.
BNL, Upton, Long Island, New York
Funding: US DOE
The National Synchrotron Light Source-II (NSLS-II) is a new ultra-bright 3GeV 3rd generation synchrotron radiation light source. The performance goals require operation with a beam current of 500mA and a bunch current of at least 0.5mA. The position and timing specifications of the ultra-bright photon beam imposes a set of stringent requirements on the radio Frequency (RF) control, among which, for example, is the 0.14 degree phase stability, and the flexibility of handling varying beam conditions. To meet these requirements, a digital implementation of the LLRF is chosen in order to be able to take the advantage of the power of precision signal processing and control that only DSP technology can provide. The initial design of NSLS II LLRF control solution is comprised of a FPGA-based basic field controller, a dual ASIC DSP co-processor directly coupled to the FPGA controller, as well as a local CPU which monitors the operation, stores the data, and facilitates the tests and development. The prototype of the basic FPGA field controller hardware has been designed. The first sample has been fabricated, and is currently being tested.
BNL, Upton, Long Island, New York
Funding: Work performed under contract number 126615 for Brookhaven Science Associates, LLC.
NSLS-II is a new ultra-bright 3GeV 3rd generation synchrotron radiation light source. The performance goals require operation with a beam current of 500mA and a bunch current of at least 0.5mA. The position and timing specifications of the photon beam place tolerances on the phase stability of the RF cavity fields of less than 0.15 degrees jitter. This study develops computational methods for the construction of LQG controllers for discrete-time models of single-cavity rf systems coupled to rigid-bunch beams able to meet this tolerance. It uses Matlab’s control-systems toolbox and Simulink to synthesize the LQG controller; establish resolutions of state variables, ADCs, DACs, and matrix coefficients that, in a fixed-point controller provide essentially undiminished performance; simulate closed-loop performance; and assess sensitivity to variations of the model. This machinery is applied to NSLS-II-, CLS-, and NSLS VUV-ring models showing exceptional noise suppression and bandwidth. Thoughts are given on the validation and tuning of the rf model by machine measurements, DSP implementations, and future work.
CIAE, Beijing
In the commissioning phase of CRM cyclotron, the RF cavity resonance frequency changes rapidly due to cavity thermal instability and electronics interference inside tuning loop. To solve the later issue, a set of cavity tuning control electronics has been re-designed, fabricated and tested in 2008. The new tuning control electronics and related experimental results will be described in this paper. A wide dynamic range phase detector with double balanced mixer were selected to detect the cavity detuning angle by comparing the phase difference between the cavity pickup signal and cavity driven signal. One analogue P.I. controller was utilized for loop regulation, taking advantage of shorter developing time. A current amplifier is also included to magnify the driven ability of the P.I. regulator for cavity fine tuning motors. A careful layout has been performed to avoid interference between RF part, DC small signal part and the current amplifier part. The desk experiment yields good phase detection sensitivity and acceptable stability after the mixer reaches natural thermal balance.
CEA, Gif-sur-Yvette
The acceleration of non relativistic particles, with a velocity lower than light velocity, in an RF cavity is more complex than for relativistic particles. Non-linear behaviours appear on the accelerator voltage because of the phase slippage inside the cavity. Moreover, a superconducting RF cavity is sensitive to various perturbations like mechanical vibrations (microphonics) and Lorentz force detuning. These perturbations produce a significant detuning of the cavity, leading a strong instability for the amplitude and phase of the field because of the narrow bandwidth of the accelerating mode. We will present a simulation approach of the cavity and its LLRF system control in order to ensure proper cavity operation under perturbations in the framework of the SPIRAL2 project.
CRE, Wuppertal
DESY, Hamburg
For future applications in Light Sources and Large Scale Linear Accelerators we have developed a fully digital LLRF system which overcomes the intrinsic problems of analogue and semi digital LLRF systems by realizing all functions in the high speed cores of FPGAs. Due to its modular design using either the ATCA or the VME form factor the LLRF system can be configured conveniently according to the specific requirements of the accelerator to control the rf field in individual resonators or in a combination of cavities. The LLRF input stage can be custom designed for rf frequencies of up to 3.9 GHz. The hardware and software architectures of the Cryoelectra digital LLRF control system are presented.
DESY, Hamburg
Warsaw University of Technology, Institute of Electronic Systems, Warsaw
TUL-DMCS, Łódź
Future RF Control systems will require simultaneuous data acquisition of up to 100 fast ADC channels at sampling rates of around 100 MHz and real time signal processing within a few hundred nanoseconds. At the same time the standardization of low-level systems are common objectives for all laboratories for cost reduction, performance optimization and machine reliability. Also desirable are modularity and scalability of the design as well as compatibility with accelerator instrumentation needs including the control system. All these requirements can be fulfilled with the new telecommunication standard ATCA when adopted to the domain of instrumentation. We describe the architecture and design of an ATCA based LLRF system for the European XFEL. Initial results of the demonstration of such a system at the FLASH user facility will be presented.
CERN, Geneva
JINR, Dubna, Moscow Region
Hardware commissioning of the LHC RF system was successfully completed in time for first beams in LHC in September 2008. All cavities ware conditioned to nominal field, power systems tested and all Low level synchronization systems, cavity controllers and beam control electronics were tested and calibrated. Beam was successfully captured in ring 2, cavities phased, and a number of initial measurements made. These results are presented and tests and preparation for colliding beams in 2009 are outlined.
CERN, Geneva
In the framework of the LHC project the concept has been developed of a global digital signal processing unit (DSPU) that implements in numerical form the architecture of low-level RF systems [1]. The approach, using an FPGA as core for the low-level system, is very flexible and allows the upgrade of the signal processing by modification of the original firmware [2]. The achieved performances of the LHC 1-Turn delay Feedback are compared with project requirements. The PS Transverse Damper DSPU, with automatic loop delay compensation adapting to the beam’s time of flight and Hilbert Filter for single pick-up betatron phase adjustment, is presented. A modified DSPU with digital inputs for the LHC Transverse Damper is also presented.
[1] V. Rossi, CERN SL-2002-047-HRF, CERN, Geneva, July 2002.
[2] V. Rossi, CERN BE-2009-009, CERN, Geneva, January 2009.
Fermilab, Batavia
DESY, Hamburg
ANL, Argonne
KEK, Ibaraki
Funding: *Work supported by Fermi Research Alliance, LLC. under ContractNo. DE-AC02-07CH11359 with the United States Department of Energy.
In September 2008 the DESY-FLASH accelerator was run with up to 550, 3 nano-coulomb bunches at 5 Hz repetition rate. This test is part of a longer term study aimed at validating ILC parameters by operation as close as possible to ILC beam currents and RF gradients. The present paper reports on the analysis that has been done in order to understand the RF control system performance during this test. Actual klystron power requirements and beam stability are evaluated with heavy beam loading conditions. Results include suggested improvements for upcoming tests in 2009
Fermilab, Batavia
Funding: Work supported by U.S. Department of Energy under contract DE-AC02-76CH03000
Progress has been made at Fermilab on the development of feed-forward and feed-back algorithms used to compensate SCRF cavity detuning, which is caused by Lorentz Forces and microphonics. Algorithms that have been developed and tested for the 1.3GHz (ILC-style) SCRF cavities (Capture Cavity II) will be reported.
GSI, Darmstadt
Funding: Project funded by the European Community under the FP6 "Structuring the European Research Area" program (SIS1002, contract number 515873)
SIS100 is a synchrotron that will be built in the scope of the FAIR (Facility for Antiproton and Ion Research) project. High intensity ion beams are required, making it necessary to damp longitudinal coupled and uncoupled bunch oscillations. For this purpose, a closed-loop control system was designed. Its processing part is based on digital signal processors (DSP) and field programmable gate arrays (FPGA) whose advantage is their adaptability to different problems by software changes. Experiments with a prototype were performed at the existing synchrotron SIS12/18 at GSI concentrating on the damping of longitudinal coupled bunch quadrupole oscillations of the lowest order. The configuration of the electronic system is described and results of the machine development experiments are reported. Finally, an outlook to the application in SIS100 is given.
KEK, Ibaraki
NETS, Fuchu-shi
Digital low-level rf (LLRF) control system has been installed in many linear accelerators to stabilize the accelerating field. In the digital LLRF system, the rf signal is down-converted into intermediate frequency for sampling at analog-to-digital converter (ADC) and the number of ADC required for vector sum feedback operation is equal to the number of cavity. In order to decrease the number of the ADCs required, a digital LLRF control system using different four intermediate frequencies has been developed at STF (Superconducting RF Test Facility) in KEK. This digital LLRF control system was operated with four superconducting cavities and the rf field stability under feedback operation was estimated. The result of the performance will be reported.
KEK, Ibaraki
NETS, Fuchu-shi
Vector-sum control of 4 superconducting cavities is examined at STF in KEK. The digital llrf control is carried out and the stabilities of rf fields are obtained. Various studies such as feedback margin necessary for enough field regulation, effects of perturbations of cavity detuning or klystron HV and so on. Performance degradation by elimination of circulators is also studied from the viewpoint of llrf system.
KEK, Ibaraki
NETS, Fuchu-shi
In STF phass-1, four-cavities are operated with vector-sum feedback (FB) control. The FB control instabilities arising from passband of TM010 mode other than π mode with FB loop-delays were measured. Further, a feedforward (FF) table was used in combination with FB control, which improved the flatness of the flat-top region. A method for reduction of overshoot in FB + FF operation is also proposed. By electrically developing a quasi-beam, the response for quasi-beam injection was also measured, and the correction on beam-loading was performed.
I-Tech, Solkan
In a feedback system the disturbances added in the receiver section are one of the major contributors to the amplitude and phase fluctuations of the fields in the RF cavities that are being controlled. It is therefore crucial to thoroughly evaluate the receiver section of the control system. Measurement results of parameters like amplitude noise, phase noise, coupling between RF channels, linearity and temperature dependent drifts of the receiver are presented. We also discuss what the influences of some of the measured parameters on phase and amplitude stability of the RF fields are. Finally, we summarize the results of the measurements and their impact on the future development of the Libera LLRF system.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
KEK, Ibaraki
JAEA, Ibaraki-ken
In the J-PARC Linac LLRF, for the cavity warming-up, the cavity resonance is automatically tuned to be the accelerating frequency (324MHz and 972MHz) with a mechanical tuner installed on the cavity. Now we are planning to introduce a new method of the cavity-input frequency matching into the digital LLRF control system instead of the cavity resonance tuning for the cavity worming-up. For the frequency matching with the detuned cavity, the RF frequency is modulated by way of phase rotation with the I/Q modulator, while the source oscillator frequency is still fixed. The phase rotation is automatically controlled by the FPGA. The detuned frequency of the cavity is obtained from phase gradient of the cavity field decay at the RF-pulse end. No hardware modification is necessary for this frequency modulation method. The cost reduction or the high durability for the mechanical tuner is expected in the future. The results of the frequency modulation test will be reported in this presentation.
NETS, Fuchu-shi
KEK, Ibaraki
Intermediate-frequency conversion technique has been widely used for rf signal detection. However, this technique has disadvantages such as temperature dependence higher order modes of downconverters. One of our recent attractive developments is the high-speed data acquisition system that combines commercial FPGA board ML555 and fast ADC (ADS5474 14bit, maximum 400MS/s and bandwidth of 1.4 GHz). Direct measurements of 1.3 GHz rf signals are carried out with 270 MHz sampling. The direct sampling method can eliminate a down-converter and avoid calibration of non-linearity of the down-converter. These results are analyzed and compared with conventional measurement system.
ORNL, Oak Ridge, Tennessee
The Spallation Neutron Source (SNS) has recently installed a prototype low level radio frequency (LLRF) control system for initial testing. This system is designed to replace the original fixed frequency, two harmonic Accumulator Ring LLRF system used to maintain a gap in the proton beam for extraction to the target. This prototype system is based on the hardware for the Linac LLRF system that has been modified to operate at the low frequencies required for the ring. The goal of the final system is to leverage the mature hardware and software of the Linac systems with the added flexibility needed to support the heavy beam loading requirements of the Accumulator Ring.
ORNL, Oak Ridge, Tennessee
Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
Four ferrite loaded resonant radio frequency (RF) cavity structures and one resistive wall current monitor (WCM) located in the South leg of the Spallation Neutron Source (SNS) accumulator ring provide a 250 ns beam extraction gap. Three ring RF cavities operate at the fundamental accumulator ring revolution frequency (~ 1.05 MHz) to bunch the beam while the fourth cavity operates at the second harmonic (~ 2.10 MHz) to suppress the peak beam current. The SNS ring low-level RF (LLRF) control system utilizes dynamic cavity tuning and proportional, integral, and derivative (PID) feedback control to regulate the amplitude and phase of the fields in the ring RF cavities. In April 2009 the SNS accelerator delivered 835 kW of beam power (928 MeV, 60 Hz, 15 uC/pulse) to the target during a neutron production run. This paper discusses operation and performance of the SNS ring LLRF system with high intensity beam loading.
PAL, Pohang, Kyungbuk
SLAC, Menlo Park, California
In PAL, We are preparing the 3GeV Linac by upgrading the present 2.5GeV Linac and new 10GeV PxFEL project. The specification of the beam energy spread and rf phase is tighter than PLS Linac. In present PLS 2.5 GeV Linac, the specifications of the beam energy spread and rf phase are 0.6%(peak) and 3.5 degrees(peak) respectively. And the output power of klystron is 80 MW at the pulse width of 4 microseconds and the repetition rate of 10 Hz. In PxFEL, the specifications of the beam energy spread and rf phase are 0.1%(rms) and 0.1 degrees(rms) respectively. We developed the modulator DeQing system for 3GeV linac and PxFEL. And the phase amplitude detection system(PAD) and phase amplitude control(PAC) system is needed to improve the rf stability. This paper describes the microwave system for the PxFEL and the PAD and PAC system.
SLAC, Menlo Park, California
ANL, Argonne
DESY, Hamburg
Funding: *Work supported by the DOE under contract DE-AC02-76SF00515
The FLASH L-Band superconducting (SC) accelerator facility at DESY has a LLRF system that is similar to that envisioned for ILC. This system has extensive monitoring capability and was used to gather performance data relevant to ILC. In particular, waveform data were recorded with beam off for three, 8-cavity cryomodules to evaluate the input rf stability, perturbations to the SC cavity frequencies and the rf overhead required to achieve constant gradient during the 800 μs pulses. In this paper, we discuss the measurements made in September 2008 and the data analysis procedures, and present key findings on the pulse-to-pulse input rf and cavity field stability.
TRIUMF, Vancouver
The rf control system for the 1.3 GHz TRIUMF e-linac elliptical superconducting cavities is a hybrid analogue/digital design. It is based in part on an earlier design developed for the 1/4 wave superconducting cavities of the ISACII linac. This design has undergone several iterations in the course of its development. In the current design, down-conversion to an intermediate frequency of 138MHz is employed. The cavity operates in a self-excited feedback loop, while phase locked loops are used to achieve frequency and phase stability. Digital signal processors are used to provide amplitude and phase regulation, as well as mechanical cavity tuning control. This version also allows for the rapid implementation of operating firmware and software changes, which can be done remotely, if the need arises. This paper describes the RF control system and the experience gained in operating this system with a single-cavity test facility.
TU Darmstadt, RTR, Darmstadt
GSI, Darmstadt
Funding: This work was partly supported by Deutsche Telekom Stiftung.
The effects of heavy beam loading on the RF control loops of a double-harmonic cavity system are examined. This cavity system that will be realized at the GSI Helmholtzzentrum für Schwerionenforschung in the scope of the SIS18 upgrade program consists of a main broadband cavity and a second harmonic narrowband cavity. The cavities comprise both an amplitude and a phase feedback loop. In addition, the narrowband cavity includes a feedback loop which controls its resonance frequency to follow the main RF frequency. After modelling the cavity system and the feedback loops, an analytic controller design is presented. In addition, longitudinal beam dynamics are added to the cavity model to allow a detailed simulation of the cavity-beam interaction. Realistic simulation results are given for an acceleration cycle of heavy-ions to demonstrate the performance of the RF control loops.
JLAB, Newport News, Virginia
Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
The RF system model based on MATLB has been developed for analyzing the basic characteristics of the LLRF control system being designed for the 12 GeV Energy Upgrade of the CEBAF accelerator. In our model, a typically complex cavity representation is simplified to in-phase and quadrature (I&Q) components. Lorentz Force and microphonic detuning is incorporated as a new quadrature carrier frequency (frequency modulation). Beam is also represented as in-phase and quadrature components and superpositioned with the cavity field vector. Afterward signals pass through two low pass filters, where the cutoff frequency is equal to half of the cavity bandwidth then they are demodulated using the same detuning frequency. Because only baseband I&Q signals are calculated, the simulation process is very fast when compared to other controller-cavity models. During the design process we successfully analyzed gain requirements vs. field stability for different superconducting cavity microphonic backgrounds and Lorentz Force coefficients. Moreover, we were able to evaluate different types of a LLRF structures:GDR* and SEL** as well as klystron power requirements for different cavities and beam loads.
*Generator Driven Resonator
**Self Excited Loop
NSRRC, Hsinchu
A superconducting accelerating RF cavity is going to be installed in 3GeV Taiwan Photon Source (TPS). It causes a reduction in bunch length in contrast with operation of normal type of RF cavity. A higher harmonic RF cavity is usually considered as an important tool to control the bunch length in the storage rings. The harmonic cavity in lengthening mode can also be helpful for improving the lifetime which is usually dominated in the storage rings by large angle intrabeam scattering (Touschek). In this paper we study the effects of third active harmonic cavity on bunch length of the TPS ring. We present the procedure, the simulation and the formulae to analyze the effects of third harmonic cavity on the rms bunch length while the main superconducting RF system is operated in 3MV. It is shown that the longitudinal rms electron bunches will lengthen up to 7.9 times for the optimum operation of the harmonic system.
SAGA, Tosu
SAGA Light Source (SAGA-LS) is a 1.4 GeV synchrotron light source consisting of an injector linac and a storage ring of 75.6 m circumference. The SAGA-LS has been routinely operated with low emittance of 25 nm-rad since its official opening in February 2006. Machine improvements, including upgrades on the control system and grid pulsar for the injector linac, construction of a new septum magnet and beam monitor systems, and current increase from 100 to 200 mA, have been made in the past years. Along with the accelerator improvements, installation and development of new insertion devices have started. The SAGA-LS ring has six 2.5-m long straight sections available for insertion devices. A planar type undulator of Saga University is in operation. In addition, an APPLE-2 type undulator producing variably polarized light has been installed during the winter shutdown of 2008. In order to address user demand for high flux hard x-rays, design of a superconducting wiggler is under discussion. Construction of an experimental setup to produce MeV photons by the laser Compton scattering is in progress, preparing for precise beam energy measurement and user experiments in future.
SLAC, Menlo Park, California
USTC/NSRL, Hefei, Anhui
There is a growing interest in producing intense, coherent x-ray radiation with an adjustable and arbitrary polarization state. The crossed-planar undulator* was first proposed by Kim for rapid polarization control in synchrotron radiation and free electron laser (FEL). Recently, a statistical analysis shows a degree of polarization over 80% is obtainable for a SASE FEL near saturation**. In such a scheme, nonlinear harmonic radiation is generated in each undulator and its polarization is controllable in the same manner. In this paper, we study the degree of polarization for the nonlinear harmonic radiation. We also discuss methods to reduce the FEL power fluctuations by operating the crossed undulator in the saturation regime.
*K.-J. Kim, Nucl. Instrum. Methods A 445, 329 (2000)
**Y. Ding and Z. Huang, Phys. Rev. ST Accel. Beams 11, 030702 (2008)
Uni HH, Hamburg
DESY, Hamburg
A seeded free-electron laser experiment at VUV wavelengths, called sFLASH, is being prepared at the existing SASE FEL user facility FLASH. Seed pulses at wavelengths around 30 nm from high harmonic generation will interact with the electron beam in sFLASH undulators upstream of the existing SASE undulator section. In this paper, sFLASH undulators are described.
ELETTRA, Basovizza
CELLS-ALBA Synchrotron, Cerdanyola del Vallès
Two variable polarization undulators have been designed and constructed as a Collaboration between CELLS and Sincrotrone Trieste*. In this paper the main magnetic and mechanical feature are summarized. Field optimization techniques are described, showing the achieved performance in terms of phase, trajectory and field integral errors.
*D.Zangrando et al. Design of two variable polarization undulators for the ALBA project, EPAC 2008, Genova, Italy
BNL, Upton, Long Island, New York
Funding: Work performed under US DOE contract DE-AC02-98CH1-886
During the course of last RHIC runs the beta-functions at the collision points (beta*) have been reduced gradually to 0.7m. In order to maximize the collision luminosity and ensure the agreement of the actual machine optics with the design one, more precise measurements and control of beta* value and beta* waist location became necessary. The paper presents the results of the implementation of the technique applied in last two RHIC runs. The technique is based on well-known relation between the tune shift and the beta function and involves precise betatron tune measurements using BBQ system as well as specially developed knobs for beta* and beta* waist location control.
ORNL, Oak Ridge, Tennessee
CERN, Geneva
BNL, Upton, Long Island, New York
PU, Princeton, New Jersey
Funding: U.S. Department of Energy contract DE-AC05-00OR22725
Operation of a mercury jet delivery system is presented. The delivery system is part of the Mercury Intense Target (MERIT) Experiment, a proof-of-principle experiment conducted at CERN in 2007 which demonstrated the feasibility of using an unconstrained jet of mercury as a target for a future Neutrino Factory or Muon Collider. The Hg system was designed to produce a 1-cm-diameter, 20 m/s Hg jet inside a high-field (15 Tesla), 15-cm-bore solenoid magnet. A high-speed optical diagnostic system allowed observation of the interaction of the jet with both 14- and 24-GeV proton beams. Performance of the Hg system during the in-beam experiment will be presented.
ODU, Norfolk, Virginia
JLAB, Newport News, Virginia
Muons, Inc, Batavia
BNL, Upton, Long Island, New York
Funding: Supported in part by USDOE STTR Grant DE-FG02-08ER86351
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. One problem is that in the simplest schemes, a separate return arc is required for each passage of the muons through the linac. 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. With these sorts of arcs and a single linac, a Recirculating Linear Accelerator (RLA) will have greater cost effectiveness and reduced losses from muon decay. We will develop the optics and 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.
UPC, Barcelona
MSU, Moscow
EPSC, CASTELLDEFELS
CIEMAT, Madrid
Elytt Energy, Madrid
A compact race-track microtron (RTM) with the maximal output energy 12 MeV is under construction at the Universitat Politècnica de Catalunya (UPC) in collaboration with the Skobeltsyn Institute of Nuclear Physics of the Moscow State University, CIEMAT and a few Spanish industrial companies and medical centers. The RTM end magnets are four-pole systems with the magnetic field created by a rare-earth permanent magnet material. As a source of electrons a 3D off-axis electron gun is used. These elements together with a C-band accelerating structure, dipole magnets, which allow to extract the electron beam with energy from 6 MeV to 12 MeV in 2 MeV step, and a focusing quadrupole are placed inside a vacuum chamber. We report on the current status of the technical design and results of tests of some of the components.
AES, Medford, NY
Funding: Work supported by The Department of Energy under SBIR Contract DE-FG02-08ER85054
From past work we found that within the cost of the String Assembly that dominates the overall cost of the cryomodules for ILC, the greatest cost elements are the helium vessel with the 2 phase pipe assembly, the niobium material, and the SRF cavity fabrication*. The cost of niobium is dependant upon market supply and demand and is essentially out of our control. We have carried out an aggressive study to reduce the cost of cavity fabrication in a high production environment**, which leaves the helium vessel for further investigation. It is recognized that significant cost savings may be realized if the helium vessel could be constructed of stainless steel instead of titanium material as is currently planned. To facilitate this change (AES) has designed a niobium to stainless steel transition assembly that will interface the helium vessel to the SRF Cavity at each end. Details of the design and analysis of the low cost helium vessel assembly are discussed along with potential cost reductions for the ILC high production run.
*E. Bonnema, J. Sredniawski,"ILC RF Unit Industrial Cost Study Methodology & Results"
**A. Favale, J. Sredniawski, M. Calderaro, E. Peterson,"ILC Cavity Fabrication Optimization for High Production"
CERN, Geneva
A full scale prototype of the Large Hadron Collider (LHC) collimator was installed in 2004 in the CERN Super Proton synchrotron (SPS). During three years of operation the prototype has been used extensively for beam tests, for control tests and also to benchmark LHC simulation tools. This operational experience has been extremely valuable in view of the final LHC implementation as well as for estimating the LHC operational scenarios, most notably to establish procedures for the beam-based alignment of the collimators with respect to the circulating beam. This was made possible by installing in the SPS a first prototype of the LHC beam loss monitoring system. The operational experience gained at the SPS, lessons learnt for the LHC operation and various accelerator physics effects that could limit the efficiency of the collimator alignment procedures are presented.
Sheffield University, Sheffield
The MICE Experiment requires a beam of low energy muons to demonstrate muon cooling. This beam is derived parasitically from the ISIS accelerator. A novel target mechanism has been developed that inserts a small titanium target into the proton beam on demand. The target remains outside the beam envelope during acceleration and then overtakes the shrinking beam envelope to enter the proton beam during the last 2 ms before beam extraction. The technical specifications for the target mechanism are demanding, requiring large accelerations and precise and reproducible location of the target each cycle. The mechanism operates in a high radiation environment, and the moving parts are compatible with the stringent requirements of the accelerator’s vacuum system. This paper will describe the design of the MICE target and how it is able to achieve its required acceleration whilst still meeting all of the necessary requirements for operation within the ISIS vacuum. The first operational linear electromagnetic drive was installed onto ISIS in January 2008 and has since been operated for over one hundred thousand actuations.
DESY, Hamburg
The DESY Engineering Data Management System, DESY EDMS, is a fully Web-based central information management platform at the European XFEL and the Global Design Effort for the International Linear Collider (ILC GDE). It provides functionality for managing documents and 3D CAD data and for performing configuration and change management. It can control complex information structures and keep track of their dependencies and history, i.e. their evolution over time. Due to its powerful capabilities for automating workflows and controlling information access, the DESY EDMS can coordinate processes and manage authorizations and responsibilities in large and complex organizations, which may include several institutes and industrial partners. Applications of the DESY EDMS range from small-scale document management for work groups, up to managing the complexity of world-wide collaborations during design and construction activities. The poster describes the architecture of the DESY EDMS, introduces some of its use cases and reports lessons learned in developing and operating the system.
DESY, Hamburg
The European XFEL has started the construction of the underground buildings. Now, the detailed design of the technical infrastructure has to be completed, covering HVAC (heating, ventilation, air conditioning), MEP (mechanical, electrical and plumbing), communication, transportation and safety. The design process is centered around the XFEL Roombook: The XFEL Roombook contains a complete catalog of XFEL buildings, floors and rooms. Future user groups specify requirements on their rooms, which are collected in a central database (Requirements Management System, RMS). Engineers create floor plans and design drawings based on the requirements. Project members can access room information, requirements and floor plans through the Web interface of the XFEL Roombook. The XFEL Roombook is in production since summer 2009 and has become a well accepted information platform for infrastructure design. The paper describes the planning process, the supporting tools and lessons learned.
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.
NSRRC, Hsinchu
The TPS (Taiwan Photon Source) of NSRRC is in the design stage now. The grounding system is crucial to the safety issue, the electrical reference level, the electrical noise and the EMI problems. In order to provide a high quality electrical environment, the grounding system should be designed carefully. The soil resistivity of the construction site was investigated first. Many different configurations of the ground grid layouts were simulated and compared. Beside the horizontal ground-conductors, the vertical ground-electrodes of 30 m are considered to be installed below the ground surface and they will reach the ground water level in hopes of minimizing the resistance of ground grid. The main goal is to obtain a ground grid with resistance lower than 0.2 ohm. A rectangular ground grid will also be installed under the new utility building. It will be connected to the ground grid of TPS to further reduce the resistance of whole grounding system, and also to eliminate the potential difference between them.
NSRRC, Hsinchu
The air conditioning system for the 3.0 GeV Taiwan Photon Source (TPS) is currently under the design phase. This paper presents the latest design of the air conditioning system for the TPS. The capacity of the air handling unit (AHU), the dimension and layout of the wind duct were specified. Numerical analysis was applied to simulate the air flow and temperature distribution in one of 24 sections storage ring. A 1/12 experimental hall was also modelled. The air flow of this area was simulated.
NSRRC, Hsinchu
To cope with increasing power cost and to confront huge power consumption of the Taiwan Photon Source (TPS) in the future, we have been conducting several power saving schemes since 2006 in the National Synchrotron Radiation Research Center (NSRRC). Those power saving schemes include optimization of chiller operation, air conditioning system improvement, power factor improvement and the lighting system improvement.
PAL, Pohang, Kyungbuk
KAERI, Daejon
Funding: Work supported by PEFP and MEST in Korea
The objectives of the cooling system of Proton Engineering Frontier Project (PEFP) Drift Tube Linac (DTL) operated in combination with the low-level RF system (LLRF) are to regulate the resonant frequency of the drift tube cavities of 350 MHz. To provide an effective means of bringing the PEFP DTL up for a resonance condition within ±5 kHz, the prototype of the cooling system has been designed and fabricated to investigate the performance features for the servo stabilization of the cavity resonant frequency. As a result, it is estimated that the resonant frequency could be regulated less than ±1 kHz with this proposed feedback temperature controlled cooling system although introducing a little nonlinear features as the reference operating temperature changes. This report describes the design and performance test results of a cooling system, including the size of water pumping skid components and the temperature control scheme.
Euclid TechLabs, LLC, Solon, Ohio
ANL, Argonne
Funding: DoE SBIR Phase I 2008
As the dimensions of accelerating structures become smaller and beam intensities higher, the transverse wakefields driven by the beam become quite large with even a slight misalignment of the beam from the geometric axis. These deflection modes can cause inter-bunch beam breakup and intra-bunch head-tail instabilities along the beam path, and thus BBU control becomes a critical issue. All new metal based accelerating structures, like the accelerating structures developed at SLAC or power extractors at CLIC, have designs in which the transverse modes are heavily damped. Similarly, minimizing the transverse wakefield modes (here the HEMmn hybrid modes in Dielectric-Loaded Accelerating (DLA) structures) is also very critical for developing dielectric based high energy accelerators. We have developed a 7.8GHz transverse mode damped DLA structure. The design and bench test results are presented in the article.
Euclid TechLabs, LLC, Solon, Ohio
LETI, Saint-Petersburg
Fermilab, Batavia
Funding: Work supported by the US Department of Energy.
Materials possessing large variations in the permittivity as a function of the electric field exhibit a rich variety of phenomena for electromagnetic wave propagation such as frequency multiplication, wave steepening and shock formation, solitary waves, and mode mixing. New low loss nonlinear microwave ferroelectric materials present interesting and potentially useful applications for both advanced and conventional particle accelerators. Accelerating structures (either wakefield-based or driven by an external rf source) loaded with a nonlinear dielectric may exhibit significant field enhancements. Nonlinear transmission lines can be used to generate short, high intensity rf pulses to drive fast rf kickers. In this paper we will explore the large signal permittivity of these new materials and applications of nonlinear dielectric devices to high gradient acceleration, rf sources, and beam manipulation. We describe planned measurements using a planar nonlinear transmission line to study the electric field dependence of the permittivity of these materials. Diagnostics include appearance of harmonics with a cw drive signal and sharpening of a pulse waveform as it propagates.
RRCAT, Indore (M.P.)
Particle accelerator programs being pursued by the Indian labs cover a broad range, encompassing accelerators for nuclear physics research (NPR) (in the low and intermediate energy range), construction of synchrotron radiation sources (SRS) as well as participation in international accelerator projects, especially those related to high energy physics. Machines for NPR include 14MV Pelletrons, augmented by home built superconducting linac boosters to enhance the energy & mass range of the ion beams, and a superconducting cyclotron which is currently undergoing commissioning at Kolkata. Two SRS, namely, a 450 MeV ring Indus-1 and 2.5 GeV booster cum light source, Indus-2, have been indigenously constructed and set up at Indore. A program is also on to develop a high current proton accelerator that will eventually be used for R&D linked to ADS. Regarding our international collaborations, Indian labs have contributed to setting up of LHC at CERN, are associated with the CLIC Test Facility 3 & Linac-4 and the FAIR project at Hamburg besides working with Fermilab on ILC/Project-X R&D. The talk will give an overview of some of the recent developments related to these activities.
ORNL, Oak Ridge, Tennessee
There are many planned or nascent particle-accelerator-based projects world-wide. Often these are large and complex projects that can benefit from strong project management. Following the premise that it is better to learn from the community’s successes rather than its mistakes, this talk will draw on successful experiences from the Oak Ridge SNS project in elaborating strategies and techniques for successful project management.
NIRS, Chiba-shi
AEC, Chiba
Based on more than ten years of experience of the carbon cancer therapy with HIMAC, we have proposed a new treatment facility for the further development of the therapy with HIMAC. This facility will consist of three treatment rooms: two rooms equipped with horizontal and vertical beam-delivery systems and one room with a rotating gantry. For the beam-delivery system of the new treatment facility, a 3D hybrid raster-scanning method with gated irradiation with patient’s respiration has been proposed. A R&D study has been carried out toward the practical use of the proposed method, although this method was verified by a simulation study. In the R&D study, we have improved the beam control of the size, the position and the time structure for the proposed scanning method with the irradiation gated with patient’s respiration. Further, owing to the intensity upgrade of the synchrotron, we can successfully extend the flattop duration, which can complete one fractional irradiation with one operation period and can increase the treatment efficiency of the gated irradiation. We will report the recent progress on HIMAC for carbon therapy.
Muons, Inc, Batavia
BNL, Upton, Long Island, New York
Funding: Work supported in part by USDOE STTR Grant DE-FG02-08ER86281 and DE AC02 98CH10886.
The U.S. muon collider community is mobilizing itself to produce a “Design Feasibility Study” (DFS) for a muon collider. This is happening on an aggressive schedule and must include the best possible simulations to support and validate the technical design. The DFS for a muon collider will require innovative new approaches to many aspects of accelerator design, and the simulations to support it will require tools with features and capabilities that are equally innovative and new. Two computer programs have emerged as the preferred and most commonly used simulation tools within the muon collider community: ICOOL (primary author: Dr. Fernow), and G4beamline (primary author: Dr. Roberts). We describe the ongoing development and testing of both tools for the DFS, including a common suite of tests to ensure that both tools give accurate and realistic results, as well as innovative user-friendly interfaces with emphasis on graphical user interfaces and windows.
The Andrzej Soltan Institute for Nuclear Studies, Centre Swierk, Swierk/Otwock
Funding: Institute for Nuclear Studies, Swierk, Poland
The five parameter method of tuning of biperiodic π/2 linear accelerating structure is presented. The method consists in analytical calculation of the five parameters determining the dispersion relation of such structure: two eigen frequencies fa and fc of accelerating and coupling cavities, the first coupling coefficient kac and two second coupling coefficients kaa and kcc, using five measured dispersion frequencies. Usually the process of tuning is based on sets of 3 cavities however, to include directly also the second coupling coeffients kaa and kcc, one should consider sets composed of five cells. For each such set, using the dispersion relation, a set of five equations for five unknowns is solved by successive elimination of unknowns by expressing them in terms of Fa = fa/f π/2. For Fa one obtains biquadratic equation. Coefficients of this equation are expressed as functions of measured quantities: dispersion phases and frequencies. Knowing Fa all other parameters are easily calculated and the Stop Band SB = fa  fc . In this way, on each step of building up the structure one can control precision of measurements and the Stop Band.
ANL, Argonne
Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06CH11357.
The Advanced Photon Source (APS), a third-generation synchrotron light source, has been in operation for eleven years. The monopulse radio frequency (rf) beam position monitor (BPM) is one of three BPM types now employed in the storage ring at the APS. It is a broadband (10 MHz) system designed to measure single-turn and multi-turn beam positions, but it suffers from an aging data acquisition system. The replacement BPM system retains the existing monopulse receivers and replaces the data acquisition system with high-speed analog-to-digital converters (ADCs) and a field-programmable gate array (FPGA) that performs the signal processing. The new system has been installed and commissioned in a full sector of the APS. This paper presents the results of testing of the beam position monitor which is now fully integrated into the storage ring orbit control and fast feedback systems.
ANL, Argonne
Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The Advanced Photon Source (APS) injector consists of a linac, a particle accumulator ring (PAR), and a booster synchrotron (booster). The PAR accumulates multiple linac bunches and compresses them into a single bunch for booster injection. Beam energy in the PAR is 325 MeV. Due to its low energy and relatively strong beam-loading effect, beam charge and phase (or timing ) monitoring is critical to the stable operations of rf control loops. We implemented a monitor system with an FPGA processor, which provides both current monitor and stripline fast waveforms. The system provides a bunch charge reading with a data rate of up to 1 MHz and a beam phase resolution of 200 ps, which are sufficient for the rf phase control loops. The system is currently used for beam tuning and diagnostics during normal operation. We are planning to build an upgraded version with fast data output and included it in the new rf control loops. We present a description of the system and the measurement results.
ANL, Argonne
Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The Advanced Photon Source (APS) has three circular machines: a 7-GeV electron storage ring (SR), a booster synchrotron (booster) of beam energy 325 MeV to 7 GeV, and a particle accumulator ring (PAR). Their tune measurement systems are based on HP 4396 network and spectrum analyzers (NASA) and HP 89400 vector spectrum analyzers (VSA). The instruments are no longer supported by the vendor and will need replacement in the future. An upgrade of these systems with FPGA-based processors has been implemented. The new systems provided faster tune history and bunch-by-bunch tune reading in addition to the original systems. We present a brief description of the implementation and performance of the new systems.
LNLS, Campinas
UNICAMP, Campinas, São Paulo
This paper reports on the LNLS experience with the digital electron beam position monitor Libera Brilliance through the realization of several standard accelerator physics experiments, taking advantage mainly of the equipment’s turn-by-turn capabilities.
LNLS, Campinas
As part of our efforts to improve beam stability in LNLS light source, we developed a system for automating tune measurements in the storage ring. This system is based on a commercial spectrum analyzer controlled via a GPIB port fed by a difference signal from a stripline pickup. Following a tandem-like approach, the software is divided in two parts: one inside the main operation software in the control system, which sends commands, and another one designed for receiving these commands and to suitably manage the analyzer The system is capable of setting the analyzer for optimal measurements for almost all operating conditions of the machine. This is achieved through feedback algorithms and triggered events. This tool improves machine diagnostics during failure conditions such as undesired magnet changes and is fast enough to enable tune tracking during particular events, such as ID movements and energy ramps.
CEA, Gif-sur-Yvette
The probe beam linac of the CTF3 test facility, named CALIFES, is developed by the CEA Saclay, the LAL Orsay and CERN to deliver short bunches (0.75 ps) with a charge of 0.6 nC to the CLIC 12 GHz accelerating structures. To setup the machine and obtain a precise beam handling, six high resolution beam position monitors (BPMs), based on a radiofrequency reentrant cavity with an aperture of 18 mm, are installed along the linac. The associated electronics is composed of an analog signal processing electronics with a multiplexing to control the six monitors. Due to mechanical tolerances, dipole mode frequencies are different for each BPMs, 100 MHz IF frequency is, therefore, used so that monitors operate in single and multi-bunches. Digitalised signals from acquisition boards are made available to the operation crew thanks to the OASIS interfaces. In this paper, the BPMs acquisition and the signal post processing, to extract the beam position, will be discussed and first beam tests will be presented.
CLASSE, Ithaca, New York
KEK, Ibaraki
Funding: NSF
We report on the performance goals and design of the CESRTA x-ray beam size monitor (xBSM). The xBSM resolution must be sufficient to measure vertical beam sizes under 20um. The xBSM images 2–4keV synchrotron radiation photons onto one-dimensional photodiode array. Instrumentation in the dedicated x-ray beam line includes upstream interchangeable optics elements (slits, coded apertures, and Fresnel zone plates), a monochrometer and the InGaAs photodiode detector. To provide sufficient x-ray flux in 2 GeV operation, the beam line is evacuated, with only a thin diamond window isolating the detector vacuum from the damping ring. The readout is a beam-synchronized FADC that is sufficient to measure consecutive bunches independently in a 4ns bunch spacing configuration.
CLASSE, Ithaca, New York
Funding: Support provided by the US National Science Foundation and the US Department of Energy.
A central component of the operation of the Cornell Electron Storage Ring as a Test Accelerator (CesrTA) for ILC Damping Rings R&D is the characterization of electron cloud growth in each of the principal vacuum chamber types in use in the storage ring. In order to facilitate measurements in chambers with tightly constrained external apertures, retarding field analyzers have been developed that can be deployed in regions with as little as 3mm of available aperture. We report on the design, fabrication, characterization and operation of devices that are presently deployed in CESR drift, dipole, and wiggler chambers.
CERN, Geneva
Poznań University of Technology, Poznań
The LHC beam loss monitoring system (BLM) consists of about 4000 monitors observing losses at all quadrupole magnets and many other likely loss locations. At the first LHC operation in August and September 2008 all monitors were active and used to observe the losses during the initial beam steerings, at collimators, at the LHC dump and during aperture scans. The different loss patterns will be discussed and compared with the expectations originating from simulations. The observed signals of the BLM system will be analysed in terms of response time, sensitivity cross talk between channels and noise performance.
LANL, Los Alamos, New Mexico
Funding: US DOE
The Compact Reconfigurable Input/Output (cRIO) hardware manufactured by National Instruments (NI) is evaluated as a wire scanner motion controller. This particular configuration utilizes a NI cRIO-9074 system combined with various C-series modules for wire scanner motion control I/O. Programs for this system have been written in LabVIEW and a majority of the motion-control functionality has been programmed into the cRIO's FPGA in order to provide the fastest motion control processing possible with cRIO. Additional topics of interest include, cRIO-based resolver-to-digital conversion and closed-loop, stepper-based motion control
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.
NSRRC, Hsinchu
The vibration issue is significant issue about the accelerator commission. The utility system has many mechanical parts and induces severe vibrations. For the purpose of tracing vibration source and preventing facility failure, the on-line vibration measurement and trace system has been developed. The system adopt programmable automation controller with FPGA function to conduct a series of data acquisition and algorithm. The system including specific analysis of time and frequency domain has also been integrated into the previous monitor and archive system. The user friendly interface may provide on-line analysis and trace vibration source via network anywhere and anytime.
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.
ANL, Argonne
Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
The corrective steering algorithm in TRACK has been recently updated to be more realistic. A simplified formalism will be presented along with the method of implementation. As an important application, the algorithm was used to determine the number of correctors and monitors required for the front-end of the HINS project at Fermilab. The algorithm allowed us also to find the optimum locations for the correctors and monitors as well as the required corrector field strength and the required monitor precision for an effective correction. This correction procedure could be easily implemented in an accelerator control-room for real-time machine operations.
ELSA, Bonn
Acceleration of polarized electrons in a fast ramping circular accelerator poses challenging demands on the control and stabilization/correction of the closed orbit and the vertical betatron tune, in particular on the fast energy ramp. In order to successfully compensate depolarizing resonances at a ramping speed of up to 7.5 GeV/sec (dB/dt = 2 T/sec), at ELSA the closed orbit is stabilized with high precision using a system of Beam Position Monitors and steerer magnets distributed along the ring. During acceleration, the beam positions are read out from the BPMs at a rate of 1 kHz and energy-dependent orbit corrections are applied accordingly by means of offline feed-forward techniques. The system is thus sensitive to dynamic effects and an orbit stabilization of 100 microns rms is achieved routinely. At the same time, the betatron tunes are stabilized to 0.01 by time-resolved tune measurement and appropriate manipulations of the machine optics. This presentation will cover the concepts and implementation of techniques for orbit stabilization required for the acceleration of a polarized electron beam in the fast ramping stretcher ring ELSA.
CERN, Geneva
The 3 km long TI 8 transfer line is used to transfer 450 GeV proton and ion beams from the SPS to LHC collider. As part of a detailed optics investigation program the chromaticity of the transfer line was measured. Kick response data of the transfer line was recorded for various extraction energy offsets in the SPS. The quadrupolar and sextupolar field errors over the whole transfer line dipoles, a systematic error of the main quadrupole strengths and the initial momentum error were estimated by a fit. Using the updated model, the chromaticity of the line was then calculated.
KEK, Ibaraki
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
MHI, Kobe
The output energy of J-PARC linac is planned to be upgraded from 181 MeV to 400 MeV by adding an ACS (Annular Coupled Structure linac) section. The debuncher system for J-PARC linac is also replaced in this energy upgrade. The new debuncher system will consist of two 972-MHz debuncher cavities with the separate-function configuration. In this configuration, the momentum jitter is corrected with the first debuncher, whereas the momentum spread is controlled with the second debuncher. This configuration is advantageous in simplifying the tuning procedure, and it is also beneficial in reducing the nonlinear effects of the debuncher cavities. In this paper, the beam dynamics design of the debuncher system is presented with some simulation results.
CERN, Geneva
For several years, a large variety of beams have been prepared in the LHC injectors, such as single-bunch and multi-bunch beams, with 25 ns, 50 ns and 75 ns bunch spacings, nominal and intermediate intensities per bunch. As compared to the nominal LHC beam (i.e. with nominal bunch intensity and 25 ns spacing) the other beams can be produced with lower transverse emittances. Beams of low transverse emittances are of interest during the commissioning phase for aperture considerations and because of the reduced long-range beam-beam effects. On the other hand machine protection considerations might lead to prefer nominal transverse emittances for safe machine operations. The purpose of this paper is to present the results of controlled transverse emittance blow-ups using the transverse feedback and octupoles. The procedures tested in the SPS in 2008 allow to tune the transverse emittances up to nominal values at SPS extraction.
NIRS, Chiba-shi
TIT, Yokohama
The screen monitor system is an important tool for beam diagnostic of the high-energy-beam transport line at the Heavy-Ion Medical Accelerator in Chiba (HIMAC). We have developed a very thin fluorescent film and high speed charge-coupled-device camera. Because the fluorescent film is very thin (ZnS:Ag 2mg/cm3), the beam is measured with semi-non-destructively. Consequently we can use more than two monitors at the same time and multiple locations. Moreover we employ a high-speed three-processer for image processing, the system can be applied for online monitoring and interlock system (100Hz). When the beam profile measured by this system is inevitably changed over the setting tolerance during therapeutic irradiation for the patient, the beam is immediately turned off. The design and measurement result by irradiation test are discussed.
NSRRC, Hsinchu
Stability of photon beam intensity, I0, is one of the most important performance merits of a modern light source. The photon intensity measured at dragon beam line (BL11) is routinely used as a reference signal for I0 stability measurements. At NSRRC, a highly stable I0 intensity is maintained in most percentage of the user beam time. Meanwhile, glitches of I0 intensity up to few tens of percentage had been observed once every few operating hours, which was a puzzle before its reason had been identified later. A spontaneous large variation of photon intensity (I/I0) caused difficulties for users operating their experiments. Here, we report our development of a dedicated electronic circuit with functionality of single-gate, which was very helpful to clarify the puzzle of I0 glitches observed at NSRRC.
NSRRC, Hsinchu
Commissioning of new digital BPM system for TLS is done recently. The new BPM system could support functionalities of turn by turn data, post-mortem and 10Hz slow data acquisition. 10 kHz fast data translation through Liberas grouping mechanism also succeeded to acquire all bpm data and integrate into the orbit feedback system. Various tests are performed systematically to confirm its performance and reliability and will be discussed in this report. We also present the functionalities and infrastructure of the related diagnostic tools. It could record 10 sec orbit data simultaneously via hardware and software event trigger at 10 kHz. Turn by turn and post mortem are also supported through embedded EPICS IOC. More integrated software tools and environment will continue to be developed for future operation.
NSRRC, Hsinchu
The orbit feedback system of the TLS has been deployed for a decade to stabilize electron closed orbit. As the upgrades of digital bpm electronics and switching power supply, the infrastructure of orbit feedback system has also been dramatically modified and rebuilt. The most primary works for the upgrade plan have been done including installation of new bpm and power supply since it was first proposed. After the ordered computer blade ready and the current updated rate raised from 1 kHz to 5 kHz or even 10 kHz, the system will evolve to a newly fast orbit feedback system. It is new scheduled to be commissioned in 2009 spring and can be expected to achieve a submicron stability of the electron beam at a bandwidth of at least 60 Hz.
ORNL, Oak Ridge, Tennessee
Funding: *SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
The new SNS Allison emittance scanner measures emittances of 65 kV ion beams over a range of ± 116 mrad. Its versatile control system allows for time-dependent emittance measurements synchronized by an external trigger, and therefore is suited for studying pulsed systems. After a programmable delay the system acquires a variable array of beam current measurements, each averaged over a changeable time span. The baseline of the current measurements are determined by averaging a fraction of 1 ms shortly before the start of the ion beam pulse. This paper presents the time evolution of emittance ellipses during the 1 ms H- beam pulses emerging from the SNS test LEBT, which is important for loss considerations. In addition it presents the time evolution of emittance ellipses during the 3 week active lifetime of an SNS H- source, which is an operational issue. Additional emittance data characterize the dependence on the electron-dump voltage, the extractor voltage, and the LEBT lens voltages, all of which were critical for reaching the 38 mA baseline H- beam current. Emittance data for the dependence on the beam current highlight the challenges for the SNS power upgrade.
Royal Holloway, University of London, Surrey
Funding: Work supported by the STFC LC-ABD collaboration and the Commission of the European Communities under the 6th Framework Programme Structuring the European Research Area, contract RIDS-RIDS-011899
A complete optical characterization of an electro-optic deflector to be used for fast laser-wire electron beam profilers performed using a 130 kHz repetition rate mode-locked laser, is presented. Incorporation of the device into the 2D laser-wire at PETRA III synchrotron at DESY is discussed.
Royal Holloway, University of London, Surrey
Kyungpook National University, Daegu
KEK, Ibaraki
UCL, London
SLAC, Menlo Park, California
Fermilab, Batavia
University of Cambridge, Cambridge
The ATF2 international collaboration is intending to demonstrate nanometre beam sizes required for the future Linear Colliders. An essential part of the beam diagnostics needed to achieve that goal is the high resolution cavity beam position monitors (BPMs). In this paper we report on the C-band system consisting of 32 BPMs spread over the whole length of the new ATF2 extraction beamline. We discuss the design of the BPMs and electronics, main features of the DAQ system, and the first operational experience with these BPMs.
SLAC, Menlo Park, California
Funding: Work supported by U.S. Department of Energy under Contract No. DE-AC02-76SF00515.
The Linac Coherent Light Source (LCLS) begins operation this year with 83 new stripline beam position monitor (BPM) processors. System requirements include several-micron position resolution for single-bunch beam charge of 200 pC. We describe the processing scheme, system specifications, commissioning experience, and performance measurements.
UCLA, Los Angeles, California
RadiaBeam, Marina del Rey
BNL, Upton, Long Island, New York
Funding: NSF grant # IIP-0724505
We describe our effort in the development of a low cost, wide-band detector/camera for generation of spatially resolved images of radiation beams in a multi-spectral range of wavelengths, from IR (infrared) to THz (terahertz). The detector (T-camera) utilizes a TLC (thermochromic liquid crystal) film as the sensitive element in a temperature controlled chamber and a CCD detector array and can be used as a powerful diagnostic for terahertz sources such as a synchrotron or an FEL
UCR, Riverside, California
The Muon Ionization Cooling Experiment (MICE) is being built at the Rutherford Appleton Laboratory (RAL) to test ionization cooling of a muon beam. Successful demonstration of cooling is a necessary step along the path toward creating future high intensity muon beams in either a neutrino factory or muon collider. MICE will reduce the transverse emittance of the beam by 10%, and spectrometers using particle physics techniques will measure the emittance reduction with an absolute precision of 0.1%. This measurement will be done with scintillating fiber tracking detectors nested inside solenoid magnets on either side of the cooling channel. Each fiber tracker contains five stations with 3 layers of fibers rotated 120 degrees with respect to each other, thereby allowing reconstruction of hit points along the path of the muons. Light is carried from the active fiber volume by clear waveguide fibers where it is detected using VLPCs (Visible Light Photon Counters). The details of the tracker commissioning using cosmic rays will be discussed in addition to the status and performance of the readout electronics*.
*Submitted on behalf of the MICE collaboration.
USTC/NSRL, Hefei, Anhui
The strip-line beam position monitor can be used as a non-intercepting emittance measurement monitor. The most important part of emittance measurement is to pick up the quadrupole component. To improve the accuracy of measurement, the response of the strip-line BPM pickups will be mapped before it’s installed in the HLS LINAC. This paper introduce the calibration system of the BPM, which consists of a movable antenna and a RF signal source, simulating the beam , a BPM moving bench with its control system, and an electronics system. When the position calibration is done first, the offset between electronic center and mechanical one of the BPM and the position sensitivity are gotten. There are two methods for quadrupole component calibration: one is indirect evaluation method that estimates the sensitivity of quadrupole component by the factor of position second moment; the other is direct method by simulation of a Gaussian beam through together many Gaussian weighted grid points. The results of two methods are given and compared. The effect of antenna’s diameter upon the fitting size of simulate beam has also been analyzed.
USTC/NSRL, Hefei, Anhui
In HLS streak camera system has been built. The system is used to measure some parameters of bunch like bunch length, longitudinal bunch profile and synchrotron frequency and so on, as it may report a direct derivation of fundamental machine characteristics. The system mainly consists of the synchrotron light extracting optics setup, the OPTOSCOPE streak camera and PC with a frame grabber interface card. The light extracting optics setup is used to extract synchrotron light at the bending magnet and the setup consists of the light extracting path and the optics imaging system. The streak camera realizes the functions of acquiring light and imaging. PC with a frame grabber interface card and ARP-Optoscope software package is used to monitor the light in real-time, acquire the image of light and analyze the data. The streak camera system operates with either synchroscan sweep mode or dual time base sweep mode. At present, some results are given, which include the bunch lengthening, the longitudinal bunch profile and the synchrotron frequency. These results are compared with the results acquired by using oscilloscope.
JAI, Oxford
The major goals of the final focus test beam line facility ATF2 are to provide electron beams with a few tens nanometer beam sizes and beam stability control at the nanometer level. In order to achieve such a level of stability beam based feedback systems are necessary at different timescales to correct static and dynamic effects. In particular, we present the design of intra-train feedback systems to correct the impact of fast jitter sources. We study a bunch-to-bunch feedback system to be installed at the extraction line to combat the ring extraction transverse jitters. In addition, we design a bunch-to-bunch feedback system at the interaction point for correction of position jitter due to the fast vibration of the magnets in the final focus. Optimum feedback software algorithms are discussed and simulation results are presented.
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
LBNL, Berkeley, California
BNL, Upton, Long Island, New York
CERN, Geneva
Funding: Work supported by Department of Energy contract DE–AC03–76SF00515 and the US LARP program.
The SPS at high intensities exhibits transverse single-bunch instabilities with signatures consistent with an Ecloud driven instability. While the SPS has a coupled-bunch transverse feedback system, control of Ecloud-driven motion requires a much wider control bandwidth capable of sensing and controlling motion within each bunched beam. This paper draws beam dynamics data from the measurements and simulations of this SPS instability, and develops initial performance requirements for a feedback system with 2-4 GS/sec sampling rates to damp Ecloud-driven transverse motion in the SPS at intensities desired for high-current LHC operation. Requirements for pickups, kickers and signal processing architectures are presented. Initial lab measurements of proof-of-principle lab model prototypes are presented for the wideband kicker driver signal functions.
SOLEIL, Gif-sur-Yvette
Ever since the first user operation, the digital transverse bunch by bunch feedback system developed at SOLEIL has successfully been operated, achieving a stable multibunch beam at the highest intensity in the two planes at zero chromaticity with a single chain working in a diagonal mode. Since then a vertical stripline, optimised to generate large deflections to combat the strong single bunch headtail instability, was installed to construct another chain. The combined use of the two chains allowed enhancing the feedback performance. In particular, by differentiating the feedback gain between high and low intensity bunches, the system is capable of working in hybrid filling modes. In parallel, online applications were integrated into the control system to allow measuring the tunes by selectively exciting a single bunch, damping and growth rates, and analysing the bunch by bunch data in frequency or time domain for post-mortem purposes. Future plans including installation of a horizontal stripline and a noise reduction by avoiding the baseband conversion of the beam signal are also discussed.
USTC/NSRL, Hefei, Anhui
IHEP Beiing, Beijing
SINAP, Shanghai
IHEP Beijing, Beijing
SSRF, Shanghai
In this paper, we introduce the BxB transverse feedback systems at Hefei Light Source (HLS), which employ an analog system and a digital system. The construction and commissioning for two feedback systems, as well as the instability analysis of beam and the experiment result of the feedback system in HLS are also presented in this paper.
USTC/NSRL, Hefei, Anhui
As low injection energy and multi-turn injection at HLS, the task of diagnosing and curing coupled-bunch instabilities becomes ever harder. The transverse analog feedback system has been redeveloped to improve effect, recently. In this paper, the new improved designs are described and new system's commissioning results are discussed. The transverse coupled bunch instability at 200MeV injection status is also experimentally studied.
ANL, Argonne
Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357
The Argonne Advanced Photon Source is in the process of developing a short-pulse x-ray (SPX) beamline capable of producing picosecond-scale x-ray pulses for use in time-resolved studies. To accomplish this, transverse deflecting cavities (crab cavities) operating at eight times the storage ring rf will be installed to enable production of short x-ray pulses at a selected beamline. Analysis reveals demanding phase and amplitude stability requirements for the cavity fields. The common-mode cavity field phase error relative to bunch arrival time is ± 10 degrees at the 2815-MHz cavity frequency while the cavity-to-cavity phase difference must be held to ± 0.07 degrees. The phase differential between the cavity phase and beamline timing must be held to ± 1 picosecond. A phase stabilized link* is being developed to transport a phase stable 351.9-MHz reference to the LLRF located at the beamline end. The delivered phase-stable reference will be used to develop rf references for the cavity LLRF, beamline laser, and streak camera. This paper will discuss the details of the design and report measured performance of the prototype.
* J. Frisch, D. Bernstein, D. Brown, E. Cisnerso, “A High Stability, Low Noise RF Distribution System,“ Proceedings of PAC2001, pp 816-818.
Cosylab, Ljubljana
ORNL RAD, Oak Ridge, Tennessee
ORNL, Oak Ridge, Tennessee
Funding: This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the U.S. Department of Energy.
Implementation of a timing system master device is a complicated task, since a lot of details have to be taken into account even once the architecture decisions have been laid down. At SNS/ORNL timing master controller is being upgraded in collaboration with Cosylab and this paper focuses on some details of its implementation. New timing system master device is based on agile FPGA circuitry and the main focus of this paper is its firmware implementation. Provided are implementation details for event distribution supporting multiple event sources and priorities. Discussed are mechanisms, ensuring deterministic behavior, different methods of encoding that have been employed, and host-independent distribution of time stamp frames. The concept of the super-cycle is explained and its implementation is laid down. Taken into account that implementation for such a complex device involves extensive testing, paper provides insight into verification it was applied. Advantages of the SystemC based test-benches over traditional VHDL-only verification are discussed.
DESY, Hamburg
Stockholm University, Stockholm
For the operation of the European X-Ray Free Electron Laser (XFEL), a system wide synchronous low-jitter clock and precise, adjustable triggers must be generated and distributed throughout the approximately 3.5 km long facility. They are needed by numerous diagnostics, controls, and experiments. Fast ADCs require the jitter of the distributed 1.3GHz clock to be in the order of a few pico seconds (RMS) and that it is synchronized to the accelerating RF. The phase of the 1.3GHz clock must therefore be adjustable at every endpoint. Due to cable lengths, and the temperature dependence of the propagation speed, temperature drifts are a serious issue. Therefore a complex monitoring and compensation mechanism has been developed to minimize these effects. Triggers must also be distributed throughout the system to synchronize different control or measurement tasks. The triggers must be adjustable in time in order to compensate for different cable lengths and should have a resolution of one ns but with ps stability. A prototype of this clock and trigger system has been developed and first measurements have shown, that the strong requirements can be fulfilled.
Uni HH, Hamburg
PSI, Villigen
DESY, Hamburg
CLASSE, Ithaca, New York
ITER, St Paul lez Durance
The free-electron laser FLASH and the planned European XFEL generate X-ray light pulses on the femtosecond time-scale. The feasibility of time-resolved pump-probe experiments, special diagnostic measurements and future operation modes by means of laser seeding crucially depend on the long-term stability of the synchronization of various laser systems across the facility. For this purpose an optical synchronization system is being installed and tested at FLASH. In this paper, we report on the development and the performance of a background-free optical cross-correlation scheme to synchronize two individual mode-locked lasers of different center wavelengths and repetition rates with an accuracy of better than 10 fs. The scheme can be tested by linking a Ti:sapphire oscillator, used for electro-optical diagnostics at FLASH, to both a locally installed erbium-doped fiber laser and the end-point of an actively length-stabilized fiber link distributing the pulses from a master laser oscillator. After the commissioning of this fiber link, the diagnostics laser can be synchronized to the electron beam and first accelerator based measurements on the performance of the system will be carried out.
NSRRC, Hsinchu
The 266 nm UV drive laser for the NSRRC 2998 MHz photo-injector system is generated from a nonlinear optical crystal that is driven by a 798 nm, 3.5 mJ Ti:Sapphire laser amplifier system. Synchronization of the seed laser pulses with the master oscillator of the photo-injector high power microwave system is done by locking the laser to the rf clock signal with time jitter of less than a picosecond. A detector circuit is being built to measure this jitter at sub-picosecond time resolution. Preliminary results of this jitter measurement electronics that have been tested with artificial signals are presented.
ELETTRA, Basovizza
Elettra is the third generation light source in operation in Trieste since 1993,upgraded with a full energy booster injector last year. Top-up operation is on schedule in the near future but already the new timing system and gun are ready to operate in this mode. The paper describes all tasks and requirements needed to satisfy top-up injection include custom made hardware, interaction with controls and radiation protection system.
JLAB, Newport News, Virginia
Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Jefferson Lab’s CEBAF accelerator operation requires various frequency signals to be distributed along the site. Three signals: 10 MHz, 70 MHz and 499 MHz are synthesized in the Machine Control Center (MCC) while 1427 MHz and 429 MHz are derived from 499 MHz and 70 MHz signals in four separate locations. We are replacing our obsolete 10 MHz, 70 MHz and 499 MHz sources with new sources that will incorporate a GPS receiver to discipline a 10 MHz reference. In addition the MO (Master Oscillator) system will be redundant (duplicate MO) and a third signal source will be used as a system diagnostic. Moreover the 12 GeV Energy Upgrade for CEBAF accelerator will be adding 80 new RF systems. To support them the distribution of 1427 MHz and 70 MHz signals has to be extended and be able to deliver enough LO (Local Oscillator) and IF (Intermediate Frequency) power to 320 old and 80 new 80 RF systems. This paper discusses the new MO and the drive line extension.
CERN, Geneva
A series of LHC injection tests was performed in August and September 2008. The first saw beam injected into sector 23; the second into sectors 78 and 23; the third into sectors 78-67 and sectors 23-34-45. The fourth, into sectors 23-34-45, was performed the evening before the extended injection test on the 10th September which saw both beams brought around the full circumference of the LHC. The tests enabled the testing and debugging of a number of critical control and hardware systems; testing and validation of instrumentation with beam for the first time; deployment, and validation of a number of measurement procedures. Beam based measurements revealed a number of machine configuration issues that were rapidly resolved. The tests were undoubtedly an essential precursor to the successful start of LHC beam commissioning. This paper provides an outline of preparation for the tests, the machine configuration and summarizes the measurements made and individual system performance.
MPQ, Garching, Munich
LMU, Garching
The author will review the remarkable world-wide field and activities of ultra-fast and exotic electron and photon sources and the science that can be accomplished through their use, as well as several specialized new sources of accelerated electrons. The areas to be covered include: the generation, manipulation and measurement of few-fs to sub-fs ultra-high phase space density electron bunches ({10}-{10}00 MeV) with ultra-intense waveform-controlled few-cycle light; the generation and measurement of few-fs to sub-fs hard X-ray pulses from the interaction of high-density electron bunches with periodic structures; laser wakefield accelerators and other exotic emerging sources; the use of these devices for science, including control and real-time observation of electron dynamics on atomic & sub-atomic scales.
CLASSE, Ithaca, New York
Commissioning of a new high brightness electron source for the Energy Recovery Linac at Cornell University is currently underway. Despite the fact that the beam dynamics in this portion of the accelerator is space-charge dominated, a fundamental understanding of the machine linear optics is crucial in that it determines the effectiveness of space-charge emittance compensation methods, as well as provides the means to achieving various beam parameters such as beam length and energy spread. Here we introduce a new numerical tool being used in the commissioning of the injector that provides linear optics matrix calculation using field maps for various optical elements.
ELETTRA, Basovizza
Funding: "The work was supported in part by the Italian Ministry of University and Research under grant FIRB-RBAP045JF2 or grant FIRB-RBAP06AWK3 or grants FIRB-RBAP045JF2 and FIRB-RBAP06AWK3"
FERMI@Elettra is a FEL user facility under construction at Sincrotrone Trieste, Italy. It will use the existing normal conducting S-band Linac and seven accelerating sections received from CERN after the LIL decommissioning. Two additional new sections are also foreseen. The Linac repetition rate will be 10 Hz during the initial stage of operation, but it will be ramped up from 10 Hz to 50 Hz. Due to the higher RF power dissipation, the temperature distribution on the copper structure will reach higher values. RF heating will imply a thermal deformation of the accelerating cavities, both in the transversal and in the longitudinal direction. Since FERMI@Elettra has stringent requirements on phase stability, the length of the section must be kept as constant as possible. In this paper the thermo-mechanic behaviour of the accelerating sections is investigated and the results of the simulations are presented. Furthermore an algorithm has been developed to control the longitudinal deformation of the sections.
IF-UFRGS, Porto Alegre
Experiments and numerical simulations show that high-intensity beams composed by charged particles usually reach their final stationary state with a progressive populating of a spatial region external to its original border. This populating process occurs in such terms that beam spatial limits at equilibrium increase by an amount of two or three times its initial nominal size. This is known as halo in Beam Physics. In this way, this work intends to better understand the time scale of halo formation. The carried out investigation has shown that the time scale of halo formation in fact can be segmented in two different quantities, each one associated to distinct physical mechanisms. One is related with the initial non-homogeneity naturally present in such systems, and the other is a result of the initial beam envelope mismatch. This investigation seems to be useful to design more efficient collimation systems and/or non-linear control systems for the next generation high-power accelerators.
TEMF, TU Darmstadt, Darmstadt
We report on a new numerical technique for the computation of geometrical wakes in three-dimensional LINAC structures. The method utilises an explicit Finite-Volume Time-Domain (FVTD) formulation. The numerical dispersion in all three axial directions is completely eliminated by choice of an appropriate staggering of the field components on the grid. Thus, contrary to most of the previously reported techniques no splitting of the time-evolution operator is necessary. This results in large savings in computational time as well as in an improved numerical accuracy. We have implemented this new technique in PBCI code and present some preliminary results.
PBPL, Los Angeles
UCLA, Los Angeles, California
Manhattanville College, Purchase, NY
The millimeter-scaleμAccelerator Platform (MAP)–essentially a “particle accelerator on a chip”–will ultimately allow for revolutionary medical and industrial applications due to its manageable size and reproducibility. The MAP consists of an electron source and an all-dielectric, laser powered, particle accelerator. The dielectric structure has two slab-symmetric reflecting mirrors with a vacuum gap between them. A periodic coupling mechanism allows laser power to enter transversely through one mirror. This mechanism is analogous to the slots of an optical diffraction grating, with coupling period and vacuum gap equal to the wavelength of the laser (800nm in this study). Work to date has included designing, fabricating and testing a prototype relativistic structure using a patterned gold layer. To go further, we have studied the fabrication techniques and electromagnetic designs of an all-dielectric (non-metallic) structure. Fabrication of the final structure is modeled after Vertical-Cavity Surface-Emitting Lasers (VCSEL) and Distributed Bragg Reflector (DBR) techniques. Preliminary numerical studies of the sub-relativistic structure are also presented.
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.
BNL, Upton, Long Island, New York
Funding: Work performed under auspices of the U.S. Department of Energy under Contract No. DE-AC02-98CH10886 with Brookhaven Science Associates, LLC.
The role of relational database (RDB) technology plays in accelelerator control and operation continues to grow in such areas as electronic log books, machine parameter definitions, and facility infrastructure management. RDBs are increasingly relied upon to provide the official 'master' copy of these data. The services provided by the RDB have traditionally not been 'mission critical'. The availability of modern RDB management systems is now equivalent to that of standard computer file-systems, and thus RDBs can be relied on to supply (pseudo-)realtime response to operator and machine physicist requests. This paper describes recent developments in the IRMIS RDB (1) project. Generic lattice support has been added, serving as the driver for model-based machine control. Abstract physics name service, with introspection has been added. Specific emphasis has been placed both on providing fast response time to accelerator operators and modeling code requests, as well as high (24/7) availability of the RDB service.
BNL, Upton, Long Island, New York
Stony Brook University, Stony Brook
Funding: Work performed under auspices of the U.S. Department of Energy under Contract No. DE-AC02-98CH10886 with Brookhaven Science Associates, LLC
This paper presents a new extension to EPICS, approaching the Data Distributed Service (DDS) interface based on the Channel Access protocol. DDS is the next generation of the middleware industrial standards, bringing a data-centric publish-subscribe paradigm to distributed control systems. In comparison with existing middleware technologies, the data-centric approach is able to provide a consistent consolidated model supporting different data dissemination scenarios and integrating many important issues, such as quality of service, user-specific data structures, and others. The paper considers different features of the EPICS-DDS layer in the context of the accelerator high-level environment and introduces a generic interface addressing various types of accelerator toolkits and use cases.
BNL, Upton, Long Island, New York
Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
An online modeling system is being developed for the RHIC injector complex, which consists of the Booster, the AGS and the transfer lines connecting the Booster to the AGS and the AGS to RHIC. Historically the injectors have been operated using static values from design specifications or offline model runs, but tighter beam optics constraints required by polarized proton running (e.g. accelerating with near-integer tunes) have necessitated a more dynamic system. An online model server for the AGS has been implemented using MAD-X as the model engine, with plans to extend the system to the Booster and the injector transfer lines and to add the option of calculating optics using the Polymorphic Tracking Code (PTC) as the model engine.
BNL, Upton, Long Island, New York
Funding: Work performed under auspices of the U.S. Department of Energy under Contract No. DE-AC02-98CH10886 with Brookhaven Science Associates, LLC.
A distributed software architecture for high level applications is under development at the NSLS-II (National Synchrotron Light Source II) project. One of the important issues is to make accelerator simulation model run on a standalone model server. To enhance the capacity of the model server, it is required to have a set of narrow and general API to accommodate various existing tracking codes. A preliminary study for the API development has been started at NSLS-II based on The MMLT (Matlab Middle Layer Toolkit).A new interface is developed for the MMLT to support another simulation engine known as Tracy. A virtual accelerator is also built for the NSLS-II storage ring based on the Tracy code and the EPICS framework. Although we don't have a real machine, we can evaluate and develop our high leval application with the support of virtual accelerator. This paper describes the current status of the software architecture for high level applications.
BNL, Upton, Long Island, New York
LBNL, Berkeley, California
Funding: U.S. Department of Energy
A new approach to embedded device control is being developed by Lawrence Berkeley Laboratory (LBNL) and Brookhaven National Laboratory (BNL). Synchronous device interface (SDI) will be implemented in NSLS-II project as a key communication protocol. This paper describes the design motivation and principles of SDI. It also discusses SDI in fast orbit feedback system and its extension in power supply control system.
Commanding Communications Academy, Wuhan
CIAE, Beijing
Under the influence of applications using virtual reality in accelerator R&D, this paper discusses the complete process of developing Communication Equipment Operation Simulation (CEOS) based on Creator/Vega Visual Scenery Simulation Technology, operation rules modeling and solutions to its key problem. The virtual scene model for communication equipment is designed with 3D modeling software MultiGen Creator, especially its DOF technology and Switch node. The basic graphs such as wires are drawn through OpenGL call-back functions. By the virtual scene drive Vega, the application of CEOS comes true. Its simulation example shows greatest traits on building similar simulation system e.g. cyclotron virtual prototyping system as well as virtual cyclotron control system.
CERN, Geneva
The 2008 collimation system of the CERN Large Hadron Collider (LHC) included 80 movable collimators for a total of 316 degrees of freedom. Before beam operation, the final controls implementation was deployed and commissioned. The control system enabled remote control and appropriate diagnostics of the relevant parameters. The collimator motion is driven with time-functions, synchronized with other accelerator systems, which allows controlling the collimator jaw positions with a micrometer accuracy during all machine phases. The machine protection functionality of the system, which also relies on function-based tolerance windows, was also fully validated. The collimator control challenges are reviewed and the final system architecture is presented. The results of the remote system commissioning and the operational experience are discussed. The system tests performed for the 2009 beam operation are also reviewed.
CERN, Geneva
The core task of the commissioning of the LHC technical systems was the individual test of the 1572 superconducting circuits of the collider, the powering tests. The two objectives of these tests were the validation of the different sub-systems making each superconducting circuit as well as the validation of the superconducting elements of the circuits in their final configuration in the tunnel. A wide set of software applications were developed by the team in charge of coordinating the powering activities (Hardware Commissioning Coordination) in order to manage the amount of information required for the preparation, execution and traceability of the tests. In all the cases special care was taken in order to keep the tools consistent with the LHC quality assurance policy, avoid redundancies between applications, ensure integrity and coherence of the test results and optimise their usability within an accelerator operation environment. This paper describes the main characteristics of these tools; it details their positive impact on the completion on time of the LHC Hardware Commissioning Project and presents usage being envisaged during the coming years of operation of the LHC.
GSI, Darmstadt
Cosylab, Ljubljana
One of the main challenges of the planned Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt is to handle its complex parallel and multiplexed beam operation. In addition, the size of the FAIR project demands for tailor-made but yet extendible solutions with respect to all technical subsystems, especially for the control system. In order to operate and maintain the large amount of front-end equipment standardized solutions are an absolute must. Moreover, to give guidelines and interface specifications to the international collaborators and external partners for so-called "in-kind contributions" facility-wide standards have to be defined. For that purpose, GSI decided to use the Front-end Software Architecture (FESA) at the lowest level of the control system. FESA was developed by CERN and is already operational at LHC and its injectors. This report presents a framework overview and summarizes the status of the FESA test installation at GSI. Additionally, first experiences with the SIS18 BPM system controlled via FESA are presented.
KEK, Ibaraki
Sokendai, Ibaraki
MELCO SC, Tsukuba
SINAP, Shanghai
The 8-GeV linac at KEK provides electrons and positrons to several accelerator facilities. A 50-Hz beam-mode switching system has been constructed to realize simultaneous top-up injections for Photon Factory and the KEKB high- and low-energy rings, which require different beam characteristics. An event-based timing and control system was built to change the parameters of various accelerator components within 20 ms. The components are spread over a 600-m linac and require changes to a total of 100 timing and control parameters. The system has been operated successfully since the autumn of 2008 and has been improved upon as beam operation experience has been accumulated. It is expected to enhance the quality of the experiments at KEKB and PF. We describe the details of this new and improved control system and present status of the accelerator operation.
IST, Lisboa
ISEL, Lisboa
The Ion Beam Laboratory of the Technological Nuclear Institute (ITN) in Lisbon has a particle accelerator based on the Van de Graaff machine which is used for research in the area of material characterization. The Van de Graaff particle accelerator* in the ITN is an horizontal electrostatic accelerator capable of producing Helium and Hydrogen ion beams with energies up to 3 MeV. The developed system comprises the accelerator turn-on and turn-off procedures during a normal run, which includes the set of terminal voltage, ion source, beam focusing and control of ion beam current and energy during operation. In addition, the computer monitors the vacuum and is able to make a detail register of the most important events during a normal run, allowing the use of the machine by less qualified technicians in safe conditions. The data acquisition system consists in PC, a data acquisition I/O board compose by with two multifunction input/output boards from National Instruments and five electronic modules. The computer control system uses a LabVIEW synoptic for interaction with the operator and an I/O board that interfaces the computer and the accelerator system.
*Rosenblatt, J. “Particle Acceleration”. London, Methuen and Co LTD., 1968.
LBNL, Berkeley, California
Funding: Supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The high-level software for the ALS injector control system is being rewritten synchronizing with the low-level hardware migration to the EPICS system*. New programs are all written in C# for the use on the new operator consoles that are Windows Vista PCs. We use SCA. NET for the channel access, WCF for IPC, and XML for configurations. GUI is currently in WinForm but moving to WPF. We will be reporting the result of the first release of the system from the aspect of the software development.
*The progress was reported at PCaPAC 2008 as http://users.cosylab.com/~mpelko/PCaPAC08/papers/mow02.pdf,and
http://users.cosylab.com/~mpelko/PCaPAC08/papers/tup018.pdf
LBNL, Berkeley, California
Funding: This work was supported by U.S. Department of Energy under Contract No. DE-AC03-76SF00098.
The Advance Light Source (ALS) is in the process of upgrading the high-level controls software. This welcome upgrade is driven by the need for a low-level controls hardware upgrade. The risk of a failure in some of the aging controls hardware is reaching a critical level. The dilemma is that replacing the low-level hardware will break some important control room applications. An effort has been started to replace all the high-level software in a way that is compatible with an incremental low-level hardware replacement. As will be presented in this paper, the plan involves combining three very different programming methods: C#, Matlab, and EPICS tools.
PAL, Pohang, Kyungbuk
The prototypes of PBPM of the four blade types were installed in front-ends 1C1 diagnostic beam line. The four-blade PBPM measure both the horizontal and the vertical positions of the photon beam. KeithleyTM picoammeters are used to record the blade current. The position in both vertical and horizontal directions is calibrated by driving the stepping motors of the PBPM through an Industrial computer. PBPM Data Acquit ion Control System (DACS) is based on Window XP platform. The DACS is equipped with an Ethernet-to-GPIB controller (GPIB-ENET/00). Using the GPIB-ENET/100, networked computers can communicate with and control IEEE 488 devices from anywhere on an Ethernet-based TCP/IP network. This is GPIB interfaces four picoammeters and Ethernet-based TCP/IP communicates by Industrial Computer. Developing with LabVIEW for Windows XP, the interface to EPICS is accomplished by means of Win32 channel Access DLL's. Our LabVIEW application program incorporates EPICS-based motor control and PC-based data acquisition, using a National Instruments I/O board, and saves position data to txt files. This paper presents the PBPM DACS for PLS Control System.
SLAC, Menlo Park, California
IHEP Beijing, Beijing
Funding: Work supported in part by the DOE Contract DE-AC02-76SF00515. This work was performed in support of the LCLS project at SLAC.
XAL, a high-level application framework originally developed by Spallation Neutron Source (SNS), has been adapted by the Linac Coherent Light Source (LCLS) project. The work includes proper relational database schema modification to better suit XAL configuration data requirement, addition of new device types for LCLS online modeling purpose, longitudinal coordinate system change to better represent the LCLS electron beam rather than proton or ion beam in the original SNS XAL design, intensively benchmark with MAD and present SLC modeling system for the online model, and various new features to the XAL framework. Storing online model data in a relational database and providing universal access methods for other applications is also described here.
SLAC, Menlo Park, California
LAL, Orsay
The Flight Simulator is a tool used for international collaboration in the writing and deployment of online beam dynamics algorithms. Written as an add-on to the Lucretia tracking software, it allows simulation of a beamline in a control system environment identical to that in the control room. This allows the testing and development of monitoring and correction tools by an international collaboration by making the control system transparent to the user. The native beamline representation are those adopted by Lucretia, so, in order to allow third party software, to interface with this system, it was necessary to develop functionality to convert the lattice to a universal representation. Accelerator Markup Language (AML), and its associated Universal Accelerator Parser (UAP), were used for this purpose. This paper describes the use of the UAP to convert the internal beamline representation to AML, and the testing of this conversion routine using the lattice description of the ATF2 final focus experiment at KEK, Japan. Also described are the inclusion of PLACET and SAD based algorithms using appropriate converters, and tests of these on the ATF2 extraction line.
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.
SLAC, Menlo Park, California
Funding: Department of Energy contract DE-ACO3-76SF00515
We describe an integrated relational database for beamline element configuration and online accelerator modelling for LCLS. It is hosted in Oracle, from which online controls software, optimization applications and feedback, use a programming interface to acquire the element data and model. Database population is by an automated process starting with a MAD deck, which is processed in Matlab to derive text files that describe the beamline elements whose data are uploaded using Oracle Loader, and the resulting Oracle APEX applications and reports are used for survey, cabling, metrology and other facilities. An automated facility for online model generation creates an XAL online model beamline description file using a database query; the resulting model is then tracked, and results can be loaded back into the database. As such, both the design or extant machine model, of the present and all previous model runs are available, and linked to the relevant element configuration. We present the process flow from the MAD design to the database, the database schema, the database applications, the process of generating a machine model, and some scientific software which uses the database.
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
The ALICE accelerator is a 35MeV energy recovery linac prototype at Daresbury in the U.K. Due to the highly experimental nature of the accelerator, there has been a strong influence of accelerator physicists in the high-level control software for the machine. Starting from the underlying EPICS-based control system, a suite of interactive commissioning software has been built using traditional software approaches, such as LabVIEW, as well as experimenting with interactive, rapid prototyping programming languages, such as Mathematica. Using the EPICS Channel Access protocols, the control system is flexible and extensible. A wide range of tools can be used to develop and debug high-level software, allowing machine physicists to use the most appropriate and familiar tools for software development.
UMD, College Park, Maryland
Funding: This work is funded by the US Dept. of Energy Offices of High Energy Physics and High Energy Density Physics, and by the US Dept. of Defense Office of Naval Research and Joint Technology Office.
Beam centroid control is an important method for optimizing the performance for accelerators, including the University of Maryland Electron Ring (UMER), which is a scaled low-energy (10KeV) storage ring. The conventional response matrix and singular value decomposition approach do not work well on the UMER because of the unique ring structure. One of the purposes of this work is to verify that the beam centroid could be controlled in the presence of very strong space charge. In this paper, we present a novel algorithm which is based on the singular value decomposition, but uses a different response matrix, which is computed from the closed equilibrium orbit and beam positions up to the first four turns in the multi-turn beam circulation. Other issues like strong coupling between the horizontal steering dipoles and vertical steering dipoles in the beam injection section will be addressed. Implementation of this algorithm leads to significant improvement on the beam positions and multi-turn operation.
Fermilab, Batavia
Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy
Since the start of Fermilab Collider Run II in 2001, the maximum weekly antiproton accumulation rate has increased from 400·1010 Pbars/week to approximately 3,700·1010 Pbars/week. There are many factors contributing to this increase, one of which involves changes to operational procedures that have streamlined and automated antiproton source production. Automation has been added to our beam line orbit control, stochastic cooling power level management, and RF settings. In addition, daily tuning efforts have been streamlined by implementing sequencer driven aggregates.
LBNL, Berkeley, California
Funding: Supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Advanced Light Source (ALS) is a third generation synchrotron light source that has been operating since 1993 at Berkeley Lab. Recently, the ALS was upgraded to achieve Top-Off Mode, which allows injection of 1.9GeV electron beam into the Storage Ring approximately every 30 seconds. The ALS Top-Off Mode Beam Current Interlock System was installed to prevent the potential hazard of injected electrons propagating down user beam lines. One of the requirements of this interlock system is a fast response time from detected event to injection trigger inhibit. Therefore, solid state devices, not electro-mechanical relays typically used in accelerator safety systems, must be used to implement the trigger inhibit logic. An FPGA-based solution was selected for this function. Since commercial FPGAs are not rated for high reliability or fail-safe operation, some of the logic resources were used to perform system self-checking to reduce the time to detect system failures and increase reliability. The implementation and self-checking functions of the Extraction Trigger Inhibit Interlock System will be discussed.
NSRRC, Hsinchu
To improve the reliability of a contemporary synchrotron as light source, a diagnostic system is crucial. A satisfactory diagnostic system must enable a clear presentation of the reason for a system fault, and provide sufficient information to the data analyzer for system recovery and improvement. To identify a fault and to monitor the operation of a RF system, many diagnostic utilities have been adopted. The architecture for the diagnostics of the TLS RF system is here reported.
SLAC, Menlo Park, California
R.W. Downing Inc., Tucson
Funding: US Department of Energy Contract DE AC03 76SF00515.
The ILC R&D electronics program at SLAC includes development of key technologies aimed at improving reliability and availability and reducing cost. This paper discusses the development of high availability interlocks and controls for the L-Band high power RF stations. A new Fast Fault Finder (F3) VME module has been developed to process both slow interlocks using FPGA logic to detect the interlock trip excursions. This combination eliminates the need for separate PLC control of slow interlocks with modules chained together to accommodate as many inputs as needed. Next a high availability platform demonstration will port the F3’s via a specially designed VME adapter module into the new industry standard ATCA[1] crate (shelf). This high-availability platform features an Intelligent Platform Management (IPMI) system to control and monitor the health of the entire system, provide redundancy as needed for the application, and demonstrate auto-failover and hot-swap to minimize MTTR. The goal is to demonstrate “five nines” (0.99999) system availability at the shelf level. A new international initiative, the xTCA for Physics Standards Working Group, will be briefly mentioned.
[1] Advanced Telecom Computing Architecture
SLAC, Menlo Park, California
Funding: Work supported by US DOE
For LCLS, an uptime of 95% of the scheduled beam time is aimed for. This is a challenging goal for a linac-driven facility, exceeding typical up time during PEP-II running by a significant amount. During the 2008 and the 2009 LCLS beam-commissioninng runs we have been gathering and analysing statistics to identify the worst offenders as far as downtime is concerned. In 2008, an overall hardware uptime of 90% was achieved, indicating the need to decrease our downtime by a factor of two. One approach to focus the effort has been to identify those faults that cause the worst performance for a system in a given time period and focus on these. Another one is to compare our MTTR performance with that of other facilities thus identifying where our processes might be improved. In this paper we will show how we track our performance and examples of the benefit of addressing identified reliability issues.
ORNL, Oak Ridge, Tennessee
RAS/INR, Moscow
Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
SNS is a high intensity hadron beam facility; so the Beam Loss Monitor (BLM) system is a crucial part of Machine Protection System and an important tool for beam tuning. The paper presents the current status of installed detectors and experimental data obtained during SNS operations. We compare several different types of BLMs and show advantages and disadvantages of each type. The electronic parts obsolescence became a real issue since the original electronics was designed about 10 years ago. The first test of our next generation BLM system is expected to be done by summer 2009. The new system will contribute to significant noise reduction and will follow a modular concept of Smart Device to achieve a higher degree of reliability and maintainability.
SLAC, Menlo Park, California
Funding: SLAC/DOE Contract DE-AC02-76-SF00515
A state-of-the-art Machine Protection System for the SLAC Linac Coherent Light Source has been designed and built to shut off the beam within one pulse during 120 Hz operation to protect the facility from damage due to beam losses. Inputs from beam loss monitors, BPMs, toroids and position switches of insertable beam line devices are connected to a number of Link Node chassis placed along the beam line. Link Nodes are connected with a central Link Processor in a star topology on a dedicated gigabit Ethernet fiber network. The Link Processor, a Motorola MVME 6100, processes fault data at 360 Hz. After processing, rate limit commands are sent to mitigation devices at the injector and just upstream of the entrance of the sensitive undulator beam line. The beam's repetition rate is lowered according to the fault severity. The SLAC designed Link Nodes support up to 96 digital inputs and 8 digital outputs each. Analog signals are handled via standard IndustryPack (IP) cards placed on the Link Node motherboards with optional transition boards for signal conditioning. A database driven algorithm running on the Link Processor provides runtime loadable and swappable machine protection logic.
ZTEC Instruments, Albuquerque
ORNL, Oak Ridge, Tennessee
The EPICS Oscilloscopes have been evaluated to perform simultaneous real-time pass-fail monitoring of two or four waveforms. The EPICS oscilloscopes are remotely controlled and monitored via LAN. Operators can control and query all instrument functions and settings, and monitor captured waveforms via EPICS PVs, an EDM panel, or via a “virtual front panel” application running in Linux or Windows. Upper and lower waveform masks used for pass-fail testing are automatically generated by the oscilloscope from a captured “golden waveform”. A variable-width output pulse is generated upon every captured waveform that passes (falls within the masks) or fails (falls outside the masks), depending on the operator’s requirements. Real-time pass-fail monitoring has been demonstrated on the teststand for the Spallation Neutron Source (SNS) injection and extraction kicker waveforms occurring both at 60Hz and 120Hz. We believe that the same instruments will also support SNS’s future requirements for real-time monitoring of waveforms at 120Hz.
Fermilab, Batavia
Funding: Work performed by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The High Intensity Neutrino Source (HINS) linac R&D program at Fermilab is constructing a first-of-a-kind superconducting H- linac. The machine will demonstrate acceleration of high intensity beam using superconducting spoke cavities, solenoidal focusing optics throughout for control of halo growth, and operation of many cavities from a single high power rf source for acceleration of non-relativistic particles. The ion source and RFQ are operational with beam and the 10 MeV room temperature cavity section is being assembled. Superconducting spoke cavity testing is proceeding. The overall status and outlook of the HINS program is presented.
NSRRC, Hsinchu
Operation performance of the linear accelerator is crucial to satisfy stringent requirements for the top-up operation of the Taiwan Light Source. The performance of linear accelerator affects injector stability directly. Efforts to improve diagnostics and develop control applications for performance characterization are on going. Enhance operation performance of 50 MeV linac is also under way. Efforts for the improvement of the linac to provide better top-up injection performance will be summary in this report.
USP/LAL, Sao Paulo
Funding: FAPESP, CNPq
The Instituto de Física da Universidade de São Paulo (IFUSP) is building a two-stage 38 MeV continuous wave racetrack microtron. This accelerator consists of a linac injector that delivers a 1.7 MeV beam to a microtron (booster) with 5 MeV exit energy. A transport line guides the beam to the main microtron to be accelerated to energies up to 38 MeV in steps of 0.9 MeV. This work describes the commissioning of the linac injector that comprises the first two accelerating structures of the IFUSP Microtron. A provisional beam line was built at the end of the linac to provide energy and current measurements. We also present results concerning RF power, RF phase, and temperature control of the accelerating structures. The first results of the chopper and buncher systems are also presented.
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
BNL, Upton, Long Island, New York
Fermilab, Batavia
TRIUMF, Vancouver
EMMA (Electron Machine with Many Applications) is a prototype non-scaling electron FFAG to be hosted at Daresbury Laboratory. NS-FFAGs related to EMMA have an unprecedented potential for medical accelerators for carbon and proton hadron therapy. It also represents a possible active element for an ADSR (Accelerator Driven Sub-critical Reactor). This paper summarises the commissioning plans for this machine together with the major steps and experiments involved along the way. A description of how the 10 to 20 MeV beam is achieved within ALICE is also given, as well as extraction from the EMMA ring to the diagnostics line and then dump.