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MOPCH054 | Plans for the Generation of Short Radiation Pulses at the Diamond Storage Ring | DIAMOND, radiation, storage-ring, optics | 160 | ||||
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Diamond is a third generation light source under commissioning in Oxfordshire UK. In view of the increasing interest in the production of short radiation pulses, we have investigated the possibility to operate with a low-alpha optics, the use of a third harmonic cavity for bunch shortening and the implementation of a crab cavity scheme in the Diamond storage ring. The results of the initial accelerator studies will be described, including the modification of the beam optics, non-linear beam dynamics optimisation and choice of RF parameters for the crab cavity operation. The expected performance of these schemes will be summarised.
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MOPCH062 | Centroid, Size, and Emittance of a Slice in a Kicked Bunch | emittance, radiation, betatron, photon | 172 | ||||
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A transversely kicked bunch will decohere due to, among other things, chromatic and amplitude-dependent tune shifts. The chromatic tune shift leads to correlation between transverse and longitudinal phase space. Such a correlation can be used for compressing synchrotron radiation of the bunch with adequate optics. In this report, we revise the decoherence calculation to derive the centroid and second moments of a beam slice in a kicked bunch, taking into account chromatic and nonlinear decoherence, but neglecting wakefield and radiation damping, etc. A simple formula for estimating slice bunch length (and potential pulse compression ratio) is given for the ideal situation.
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MOPCH076 | Baseline Design for the Facility for Antiproton and Ion Research (FAIR) Finalized | antiproton, ion, storage-ring, GSI | 205 | ||||
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The baseline design for the future international facility FAIR has been worked out. The unique accelerator complex will provide high intensity ion beams ranging from antiprotons to uranium for nuclear matter and hadron physics studies. Radioactive beams are generated for nuclear structure and astrophysics experiments. Phase space compression utilizing stochastic and electron cooling allow for fundamental tests at highest precision. Centered around two fast ramping superconducting synchrotrons, ions are accelerated to a beam rigidity of up to 100 Tm and 300 Tm, respectively. Two dedicated storage rings serve for beam accumulation and cooling, providing unprecedented beam quality for experiments in the NESR and HESR storage rings. An overview of the layout of the accelerator complex and beam delivery systems is given. Ongoing R&D activities are reported; project status and international participation will be presented.
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MOPCH079 | Ion Optical Design of the Heavy Ion Synchrotron SIS100 | ion, extraction, lattice, acceleration | 214 | ||||
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We present the ion optical design of SIS100, which is the main synchrotron of the FAIR project. The purpose of SIS100 is the acceleration of high intensity heavy ion and proton beams and the generation of short compressed single bunches for the production of secondary beams. Since ionization in the residual gas is the main loss mechanism, a new lattice design concept had to be developed, especially for the operation with intermediate charge state heavy ions. The lattice was optimized to generate a peaked loss distribution in charge separator like lattice cells. Thereby it enables the control of generated desorption gases in special catchers. For bunch compression, the lattice provides dispersion free straight sections and a low dispersion in the arcs. A special difficulty is the optical design for fast and slow extraction, and the emergency dumping of the high rigidity ions within the same short straight section.
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MOPCH087 | Quasi-adiabatic Transition Crossing in the Hybrid Synchrotron | acceleration, induction, proton, beam-losses | 234 | ||||
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Non-adiabatic features around the transition energy are well-known to be one of most important beam physics issues in most of circular hadron accelerators. A novel technique to avoid them by the adiabatic motion, a quasi-adiabatic focusing-free transition crossing (QAFFTC), was proposed. In a longitudinally separated function-type accelerator*, in which particles are confined by an rf voltage or burrier voltages and accelerated by a step voltage, the confinement voltage can be arbitrarily manipulated as long as the particles do not diffuse, while a strict acceleration voltage is necessary for the orbit of a charged particle to be balanced in the radial direction. The introduction of QAFFTC is most suitable for the longitudinally separated function-type accelerator. This new method was examined in this type of accelerator**, both theoretically and experimentally. This was a first and significant application of the hybrid synchrotron. The results will be presented.
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*K. Takayama and J. Kishiro, Nucl. Inst. Meth. A 451, 304 (2000).**K. Takayama et al. Phys. Rev. Lett. 94, 144801 (2005). |
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MOPCH090 | ITEP-TWAC Status Report | ion, injection, booster, accumulation | 243 | ||||
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Three years of successful operation the ITEP-TWAC facility delivers proton and ion beams in several modes of acceleration and accumulation of by using the multiple charge exchange injection technique*. Substantial progress is achieved in output ion beam current intensity of the linear injector I3, in intensity of the buster synchrotron UK, in efficiency increasing of ion beam stacking and longitudinal compression in the storage ring U10. The machine status analysis and current results of activities aiming at subsequent improvement of beam parameters for extending beam technology applications are presented.
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*N. Alexeev et al. Laser and Particle Beams (2002) V 20, N3, 385-392. |
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MOPCH097 | CERN Proton Synchrotron Working Point Control Using an Improved Version of the Pole-face-windings and Figure-of-eight Loop Powering | power-supply, CERN, controls, injection | 264 | ||||
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The working point of the CERN Proton Synchrotron, which is equipped with combined function magnets, is controlled using pole-face-windings. Each main magnet consists of one focusing and one de-focusing half-unit on which four pole-face-winding plates are mounted containing two separate coils each, called narrow and wide. At present they are connected in series, but can be powered independently. In addition, a winding called the figure-of-eight loop, contours the pole faces and crosses between the two half units, generating opposite fields in each half-unit. The four optical parameters, horizontal and vertical tune and chromaticity, are adjusted by acting on the pole-face-winding currents in both half units and in the figure-of-eight loop, leaving one physical quantity free. The power supply consolidation project opened the opportunity to use five independent power supplies, to adjust the four parameters plus an additional degree of freedom. This paper presents the results of the measurements that have been made in the five-current mode together with the influence of the magnetic nonlinearities, due to the unbalance in the narrow and wide winding currents, on the beam dynamics.
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MOPCH101 | On the Feasibility of a Spin Decoherence Measurement | polarization, RHIC, proton, AGS | 276 | ||||
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In this paper, we study the feasibility of making a turn-by-turn spin measurement to extract the spin tune of a synchrotron from a polarized beam injected perpendicular to the stable spin direction. For the ideal case of a zero-emittance beam with no spin-tune spread, there would be no spin decoherence and a measurement of the spin tune could easily be made by collecting turn-indexed polarization data of several million turns. However, in a real beam there is a momentum spread which provides a tune spread. With a coasting beam the tune spread will cause decoherence of the spins resulting in a fast depolarization of the beam in a thousand turns. With synchrotron oscillations the decoherence time can be greatly increased, so that a measurement becomes feasible with summation of the turn-by-turn data from a reasonable number of bunches (100 or fewer). Both the cases of a single Siberian snake and a pair of Siberian snakes are considered.
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MOPCH114 | Progress on Dual Harmonic Acceleration on the ISIS Synchrotron | acceleration, proton, power-supply, controls | 309 | ||||
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The ISIS facility at the Rutherford Appleton Laboratory in the UK is currently the most intense pulsed, spallation, neutron source. The accelerator consists of a 70 MeV H- Linac and an 800 MeV, 50 Hz, rapid cycling, proton Synchrotron. The synchrotron beam intensity is 2.5·1013 protons per pulse, corresponding to a mean current of 200 μA. The synchrotron beam is accelerated using six, ferrite loaded, RF cavities with harmonic number 2. Four additional, harmonic number 4, cavities have been installed to increase the beam bunching factor with the potential of raising the operating current to 300 μA. As ISIS has a busy user schedule the time available for dual harmonic work has been limited. However, much progress has been made in the last year and encouraging results have been obtained. This paper reports on the hardware commissioning and beam tests with dual harmonic acceleration.
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MOPCH115 | Transverse Space Charge Studies for the ISIS Synchrotron | resonance, space-charge, simulation, focusing | 312 | ||||
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The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. It is based on a 50 Hz proton synchrotron which, once the commissioning of a new dual harmonic RF system is complete, will accelerate about 3.5·1013 protons per pulse from 70 to 800 MeV, corresponding to mean beam powers of 0.2 MW. Following this upgrade, transverse space charge is expected to be one of the main intensity limitations, and is also a key factor for further machine upgrades. A programme of R&D on transverse space charge is now under way, aiming not only to improve the ISIS ring but also to exploit it as an experimental tool for testing theory and codes. This paper summarises work so far, outlining calculations for coherent envelope modes on ISIS, using numerical solutions of the envelope equation to show the expected behaviour near half integer resonance. Progress on work linking these predictions with more realistic beam models in space charge codes, and extending calculations to images, coupling and non linear resonances will be described. Plans and preparations for experiments, along with initial results, will also be presented.
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MOPCH118 | Wideband Low-output-impedance RF System for the Second Harmonic Cavity in the ISIS Synchrotron | impedance, beam-loading, controls, acceleration | 321 | ||||
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Wideband low-output-impedance RF system for the second harmonic cavity in the ISIS synchrotron has been developed by the collaboration between Argonne National Laboratory, US, KEK, Japan and Rutherford Appleton Laboratory, UK. Low output impedance is realized by the feedback from plate output to grid input of the final triode amplifier, resulting in less than 30 ohms over the frequency range of 2.7 - 6.2 MHz which is required for the second harmonic cavity. The vacuum tubes in the driver and final stages are both operated in class A, and a grid bias switching system is used on each tube to avoid unnecessary plate dissipations during a non-acceleration cycle. High power test was performed with a ferrite-loaded second harmonic cavity, where the bias current was swept at 50 Hz repetition rate. The maximum voltage of 12kV peak per accelerating gap was obtained stably at earlier period of an acceleration cycle. A beam test with this system is planned at the ISIS synchrotron in order to investigate how the low impedance system works under heavy beam loading conditions, and is capable of mitigating the space charge detuning at the RF trapping stage.
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MOPCH119 | Present Status of the Induction Synchrotron Experiment in the KEK PS | induction, acceleration, KEK, proton | 324 | ||||
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A concept of the induction synchrotron, which was proposed by Takayama and Kishiro in 2000, has been demonstrated by using the KEK PS since 2004. A proton bunch trapped in the RF bucket was accelerated with the induction acceleration devices from 500 MeV to 8 GeV*, which was energized with the newly developed switching power supply. This form of the KEK PS is something like a hybrid synchrotron. In addition, the injected proton bunch was confined by the step barrier-voltages at the injection energy of 500MeV**, which were generated with the same induction acceleration device. Then a concept of the induction synchrotron that a proton bunch was captured by the barrier bucket and accelerated with the induction voltage is to be fully demonstrated.
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*K. Takayama et al. "Observation of the Acceleration of a Single Bunch by Using the Induction Device in the KEK Proton Synchrotron", Phys. Rev. Lett., 94, 144801 (2005).**K. Torikai et al. "Acceleration and Confinement of a Proton Bunch with the Induction Acceleration System in the KEK Proton Synchrotron", submitted to Phys. Rev. ST-AB (2005), KEK-Preprint 2005-80 A, December 2005. |
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MOPCH126 | Accelerator Research on the Rapid Cycling Synchrotron at IPNS | acceleration, proton, extraction, injection | 339 | ||||
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The Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory is a national user facility for neutron scattering. Neutrons are produced by 70 ns pulses of protons (~3x 1012 protons per pulse) impacting a depleted-uranium target at a pulse repetition rate of 30 Hz. Three accelerators in series (a 750 keV Cockcroft-Walton, 50 MeV Alvarez linac accelerating H- ions, and a 450 MeV rapid-cycling proton synchrotron) provide the beam that is directed to the target. New diagnostics and a third rf cavity that can be operated at either the fundamental or second harmonic of the ring frequency have recently been installed and an experimental program established to try to gain understanding of an instability that limits the charge-per-bunch in the RCS. This program will be described, and preliminary results presented.
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MOPCH136 | China Spallation Neutron Source Accelerators: Design, Research, and Development | linac, injection, target, extraction | 366 | ||||
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The Beijing Spallation Neutron Source (BSNS) is a newly approved high power accelerator project based on a H- linear accelerator and a rapid cycling synchrotron. During the past year, several major revisions were made to the design including the type of the front end, linac frequency, transport layout, ring lattice, and type of ring components. Possible upgrade paths were also laid out: based on an extension of the warm linac, the ring injection energy and the beam current could be raised doubling the beam power on target to reach 200 kW; an extension with a superconducting RF linac of similar length could raise the beam power near 0.5 MW. Based on these considerations, research and development activities are started. In this paper, we discuss the rationale of design revisions and summarize the recent work.
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MOPCH137 | An Anti-symmetric Lattice for High Intensity Rapid-cycling Synchrotrons | injection, lattice, collimation, dipole | 369 | ||||
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Rapid cycling synchrotrons are used in many high power facilities like spallation neutron sources and proton drivers. In such accelerators, beam collimation plays a crucial role in reducing the uncontrolled beam loss. Furthermore, the injection and extraction section needs to reside in dispersion-free region to avoid couplings; a significant amount of drift space is needed to house the RF accelerating cavities; orbit, tune, and chromatic corrections are needed; long, uninterrupted straights are desired to ease injection tuning and to raise collimation efficiency. Finally, the machine circumference needs to be small to reduce construction costs. In this paper, we present a lattice designed to satisfy these needs. The lattice contains a drift created by a missing dipole near the peak dispersion to facilitate longitudinal collimation. The compact FODO arc allows easy orbit, tune, coupling, and chromatic correction. The doublet straight provides long uninterrupted straights. The four-fold lattice symmetry separates injection, extraction, and collimation to different straights. This lattice is chosen for the Beijing Spallation Neutron Source synchrotron.
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MOPLS006 | Adaptive RF Transient Reduction for High Intensity Beams with Gaps | feedback, LHC, simulation, beam-losses | 541 | ||||
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When a high-intensity beam with bunch-trains and gaps passes a cavity with a high-gain vector feedback enforcing a constant voltage, large transients appear, stressing the RF high power hardware and increasing the trip rate. By modulating the cavity voltage with a varying periodic waveform (set-function), the RF power can be made constant while still preserving the high feedback gain. The average cavity voltage is conserved but bunches have to settle at slightly shifted positions. A method is derived to obtain this set-function in practice while making no assumptions or measurements of the beam or RF parameters. Adiabatic iterations are made, including the whole machine as an analog computing device, using all parameters as they are. A computer simulation shows the success of the method.
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MOPLS042 | Longitudinal Beam Stability for CESR-c | feedback, luminosity, positron, storage-ring | 634 | ||||
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The Cornell Electron-Positron Storage Ring (CESR) operates at 1.9 GeV per beam for high energy physics collisions. To maintain high luminosity it is essential for the bunch trains to be longitudinally stable. Measurements of longitudinal stability with a single, multiple, and colliding trains have been performed using a dual sweep streak camera and are presented in this paper.
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MOPLS044 | Luminosity Variations along Bunch Trains in PEP-II | luminosity, electron, quadrupole, positron | 640 | ||||
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In spring of 2005 after a long shut-down, the luminosity of the B-Factory PEP-II decreased along the bunch trains by about 25-30%. There were many reasons studied which could have caused this performance degradation, like a bigger phase transient due to an additional RF station in the Low-Energy-Ring (LER), bad initial vacuum, electron cloud, chromaticity, steering, dispersion in cavities, beam optics, etc. The initial specific luminosity of 4.2 sloped down to 3.2 and even 2.8 for a long train (typical: 130 of 144), later in the run with higher currents and shorter trains (65 of 72) the numbers were more like 3.2 down to 2.6. Finally after steering the interaction region for an unrelated reason (overheated BPM buttons) and the consequential lower luminosity for two weeks, the luminosity slope problem was mysteriously gone. Several parameters got changed and there is still some discussion about which one finally fixed the problem. Among others, likely candidates are: the LER betatron function in x at the interaction point got reduced, making the LER x stronger, dispersion reduction in the cavities, and finding and fixing a partially shorted magnet.
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MOPLS052 | Luminosity Improvement at PEP-II Based on Optics Model and Beam-beam Simulation | luminosity, simulation, optics, sextupole | 661 | ||||
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The model independent analysis (MIA) has been successfully used at PEP-II to understand machine optics and improve the luminosity. However, the rate of success was limited because the improvement of optics does not necessarily lead to increase of luminosity. Recently, we were able to reconstruct MIA model in a full optics code, LEGO, and used it to calculate complete lattice and beam parameters. These parameters were fed to the beam-beam code, BBI, to understand the luminosity histories at PEP-II over the past year. Using these tools, we optimized the luminosity by varying the beam parameters such as emittance. Finally, we implemented an optimized solution with a set of asymmetric horizontal orbit bumps into the machines during a delivery shift with a few percentage gain in luminosity. The solution was retained at PEP-II machines along with the luminosity. Later, these asymmetric bumps also played a vital role in reaching 1x1034cm-2s-1 as the beam currents increased.
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MOPLS064 | Measurement of Ground Motion in Various Sites | site, ground-motion, DESY, LHC | 691 | ||||
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This presentation will be an overview of a study program, initiated in DESY, to measure ground vibration of various sites which can be used for site characterization for the International Linear Collider (ILC) design. Commercial broadband seismometers have been used to measure ground motion, correlation and surface wave velocity. The database of measured ground vibrations is available to the scientific community. A parameterization of the spectra will also be presented.
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MOPLS067 | Test Beam Studies at SLAC's End Station A, for the International Linear Collider | SLAC, linac, emittance, linear-collider | 700 | ||||
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The SLAC Linac can deliver to End Station A a high-energy test beam with similar beam parameters as for the International Linear Collider for bunch charge, bunch length and bunch energy spread. ESA beam tests run parasitically with PEP-II with single damped bunches at 10Hz, beam energy of 28.5 GeV and bunch charge of (1.5-2.0)·1010 electrons. A 5-day commissioning run was performed in January 2006, followed by a 2-week run in April. We describe the beamline configuration and beam setup for these runs, and give an overview of the tests being carried out. These tests include studies of collimator wakefields, prototype energy spectrometers, prototype beam position monitors for the ILC Linac, and characterization of beam-induced electro-magnetic interference along the ESA beamline.
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MOPLS071 | TDR Measurements in support of ILC Collimator Studies | impedance, simulation, electron, SLAC | 712 | ||||
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In this report the outcome of the "wire method" cold test, experimental results and their relevance toward the ILC set-up is considered. A wire is stretched through the centre of a vessel along the axis that the electron beam would take, and a voltage pulse representing the electron bunch is passed along the wire. The parasitic mode loss parameter from this voltage can then be measured. The bunch length for the ILC is 0.3mm, requiring a pulse rise time of ~1ps. The fastest rise time available for a time domain reflectrometry (TDR) scope is ~10ps. Reference vessels have been examined to evaluate the suitability of the test gear at comparable bunch structures to the ILC.
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TUZAPA02 | ISIS Upgrades A Status Report | target, proton, linac, rfq | 935 | ||||
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Since 2002 several accelerator upgrades have been made to the ISIS spallation neutron source at the Rutherford Appleton Laboratory in the UK, and upgrades are currently continuing in the form of the Second Target Station Project. The paper reviews the upgrade programmes: a new extraction straight, replacement of the Cockcroft-Walton by an RFQ, installation of a second harmonic RF system, replacement and upgrading of installed equipment, design and installation of improved diagnostics in conjunction with beam dynamics simulations, the Second Target Station Project, design and construction of a front end test stand, and the MICE programme. The paper also looks forward to possible future schemes at ISIS beyond the Second Target Station Project.
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Transparencies
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TUOAFI01 | Development for New Carbon Cancer-therapy Facility and Future Plan of HIMAC | linac, ion, injection, rfq | 955 | ||||
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The first clinical trial with carbon beams generated from the HIMAC was conducted in June 1994. The total number of patients treated is now in excess of 2500 as of December 2005. Based on our 10 years of experience with the HIMAC, we have proposed a new carbon-ion therapy facility for widespread use in Japan. The key technologies of the accelerator and irradiation systems for the new facility have been developed since April 2004. The new carbon-therapy facility will be constructed at Gunma University from April 2006. As our future plan for the HIMAC, further, a new treatment facility will be constructed at NIRS from April 2006. The design work has already been initiated and will lead to the further development of the therapy with the HIMAC. The facility is connected with the HIMAC accelerator complex and has two treatment rooms with horizontal and a vertical beam-delivery systems and one room with a rotating gantry. We will report the development for new carbon therapy facility and the design study for new treatment facility with the HIMAC.
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Transparencies
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TUOBFI01 | A Diagnostic Kicker System as a Versatile Tool for Storage Ring Characterisations | kicker, diagnostics, storage-ring, controls | 974 | ||||
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For the BESSY II Synchrotron Light Source two diagnostic kicker systems including current pulsers were developed, allowing vertical and horizontal deflection of the stored beam. Synchronised with the revolution trigger, simultaneous pulsing of the systems kicks the stored beam in any transverse direction with a repetition rate of up to 10 Hz allowing a wide range of storage ring investigations. Examples are dynamic aperture measurements and frequency map measurements. Special efforts were made to assure the demands of high amplitude and time stability for this kind of experiments. The technical concept of the systems and the controlling of the measurements are described.
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Transparencies
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TUOCFI03 | RF Cavity with Co-based Amorphous Core | acceleration, impedance, controls, feedback | 983 | ||||
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A compact acceleration cavity has been developed with new Co-based amorphous cores, which will be used in a dedicated synchrotron for cancer therapy. This core has high permeability that makes the cavity length short, and the cavity with no tuning system is possible with low Q-value of about 0.5. An acceleration cavity consists of two units that have a single acceleration gap at the center, and at the both side of the gap there are quarter wave coaxial resonators. Considering the requirements for easy operation, a transistor power supply was used instead of commonly used tetrode in the final stage RF amplifier. Each resonator has maximum impedance about 400? at 3MHz, and has been attached with 1:9 impedance transformer. In the frequency range from 0.4 to 8 MHz, the acceleration voltage of more than 4kV can be obtained with total input RF power of 8kW. With these performances, the cavity length is short as 1.5m. In this paper the structure of the cavity and their tested high power performances are presented.
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Transparencies
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TUPCH003 | Diagnostics and Timing at the Australian Synchrotron | diagnostics, storage-ring, injection, kicker | 995 | ||||
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The 3GeV Australian Synchrotron will begin operation in March 2007. This paper outlines the storage ring diagnostics systems and the injection timing system. The diagnostics system includes an optical beamline with streak camera, an x-ray beamline with pinhole array, a diagnostic straight with fast feedback kicker, stripline, direct current current transformer, and a four-fingered scraper. Over the 14 sectors there are 98 beam position monitors and 14 movable beam loss monitors. The timing system is based on a static injection system with the storage ring bucket to be filled targeted by delaying the firing of the electron gun.
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TUPCH004 | Commissioning of the LNLS X-ray BPMs | electron, diagnostics, dipole, feedback | 998 | ||||
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We present experimental results of the commissioning of staggered-pair blade X-Ray beam position monitor (XBPM) recently developed and installed at the diagnostic beamline of the UVX electron storage ring at the Brazilian Synchrotron Light Laboratory (LNLS). The results obtained with a prototype XBPM indicate that the short-term and long-term data are both in agreement with the data from a commercially acquired XBPM installed at the same beamline, as well as with the data of the electron storage ring RF BPMs. In this paper we present the commissioning results of the LNLS XBPM.
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TUPCH008 | Behavior of the BPM System During the First Weeks of SOLEIL Commissioning | SOLEIL, storage-ring, instrumentation, electron | 1007 | ||||
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SOLEIL, a new synchrotron light source built near Paris in France, is pioneering a new high resolution electron Beam Position Monitor (BPM) system to achieve stability of the beams at the micron level, as required for the beamlines. The same BPM system allows also measurement of the beam position in turn-by-turn mode for various machine physics studies. The system combines the high stability characteristic of multiplexed input channels and the flexibility of a digital system. Instrumentation Technologies developed the Libera module upon SOLEIL proposals and requirements. The performances of the system evaluated after the Booster and the storage ring commissioning will be presented.
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TUPCH009 | Beam Measurements and Manipulation of the Electron Beam in the BESSY-II Transferline for Topping Up Studies | emittance, quadrupole, booster, injection | 1010 | ||||
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The BESSY-II storage ring based synchrotron radiation source will be upgraded to allow for continuous topping up operation. In order to achieve a high injection efficiency between the booster synchrotron and the storage ring, the transferline will be equipped with novel beam size monitors and collimators. This paper describes the collimator design and first beam measurements of the transverse emittance. The transverse emittance is measured using the quadrupole scan technique. The data taking and the analysis procedure is given together with results and comparision with simulations.
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TUPCH011 | Innovative Beam Diagnostics for the Challenging FAIR Project | diagnostics, ion, feedback, cryogenics | 1016 | ||||
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The planned FAIR facility consists of two heavy ion synchrotrons and four large storage rings. The super-conducting synchrotrons are build for high current operation and secondary ion production. A large variety of low current secondary beams is stored and cooled in the four storage rings. A complex operation scheme with multiple use of transport lines is foreseen. This demands an exceptional high dynamic range for the beam instrumentation. Due to the enormous beam power, non-destructive methods are mandatory for high currents. For the low current secondary beams, non-destructive diagnostics are also preferred due to the low repetition rate. Precise measurements of all beam parameters and automatic steering or feedback capabilities are required due to the necessary exploitation of the full ring acceptances. Moreover, online beam-corrections with short response times are mandatory for the fast ramping super-conducting magnets. Due to the ultra-high vacuum condition and the demanding measurement accuracy, novel technical solution are foreseen. An overview of the challenges and projected innovative solutions for various diagnostic installations will be given.
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TUPCH012 | Digital Techniques in BPM Measurements at GSI-ISI | acceleration, pick-up, feedback, GSI | 1019 | ||||
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In this paper we describe new approaches for BPM measurements in hadron accelerators, which have strongly varying beam parameters such as intensity, accelerating frequency and bunch length. Following signal dynamic adjustment, direct digitalization and treatment of digitized data, we should reach a BPM resolution of 0.1mm. Interchangeability of this method between accelerators should be provided, which results in autonomous data treatment algorithms, free of external status and timing signalling. This should ensure the usability of the system in other bunched accelerator rings. Different operation modes are intended for allowing online storage of beam position data over full acceleration cycles as well as storage of beam waveforms in regions of acceleration that are of special interest e.g. transition, kicking, bunch gymnastics. First results of realised hardware/software combinations will be introduced and discussed.
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TUPCH016 | Numerical Simulation of Synchrotron Radiation for Bunch Diagnostics | simulation, radiation, vacuum, DESY | 1031 | ||||
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For the operation of the VUV-FEL at DESY, Hamburg, the longitudinal charge distribution of the electron bunches that drive the free electron laser is of high importance. One novel method to measure the bunch shape is to analyze the coherent far-infrared synchrotron radiation generated at the last dipole magnet of the first bunch compressor. For the correct interpretation of the results it is mandatory to know how various parameters, like the bunch shape and path, the vacuum chamber walls, the optical beamline, etc., influence the observed spectrum. The aim of this work is to calculate the generation of synchrotron radiation inside the bunch compressor with the emphasis of including the effects of the vertical and horizontal vacuum chamber walls in the vicinity of the last dipole magnet. Challenging problems for the numerical simulations are the very short wavelength and the broad frequency range of interest. As a first step, it is shown how the radiation leaving the vacuum chamber, that is generated by a single point charge, can be calculated with the help of the uniform theory of diffraction (UTD).
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TUPCH018 | Fast Beam Dynamics Investigation Based on an ADC Filling Pattern Measurement | CBM, controls, diagnostics, storage-ring | 1034 | ||||
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A diagnostic tool to determine the longitudinal particle filling pattern has been installed at the 1.5 GeV electron storage ring DELTA. The instrument is PC-based using an ADC-conversion at a sampling rate of 2 GS/s and a nominal bandwidth of 1 GHz which is applied to the sumsignal of a single storage ring beam position monitor. By sampling over successive turns the resolution is enhanced by one order of magnitude allowing an easy access to the longitudinal particle distribution inside the ring. The data obtained turn-by-turn over hundreds of revolutions can be further analysed by FFT-techniques allowing a very fast detection (~ 1 s) of longitudinal coupled bunch mode (CBM) instabilities from the phase modulated spectrum. The application of the FFT to the amplitude modulated particle distribution moreover allows a "post mortem"-investigation of CBM induced beam loss. The paper will present the layout of the diagnostic system and will report on filling pattern measurements as well as on investigations of longitudinal CBM-instabilities.
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TUPCH023 | Direct Observation of Beam-beam Induced Dynamical Beta Beating at HERA | electron, luminosity, proton, synchrotron-radiation | 1046 | ||||
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The Hadron Electron Ring Anlage (HERA) at DESY provides collisions between a 920 GeV proton beam and a 27.5 GeV electron beam in two interaction regions. The strong beam-beam force, which mainly affects the electrons, induces a tune shift together with a dynamical beta beat. The latter leads to a modification of the transverse beam profile, which can be observed in different profile monitors in HERA. The time-like evolution of the electron beam shape during luminosity tuning and before and after dump of the proton beam, averaged over all bunches, could be studied by means of a synchrotron radiation profile monitor. Measurements with a wire scanner allowed to see the beam-beam force's influence on each individual bunch at the expense of resolution. The observations could be explained qualitatively in the frame of linear incoherent beam-beam interaction.
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TUPCH032 | Precise Measurements of the Vertical Beam Size in the ANKA Storage Ring with an In-air X-ray Detector | resonance, electron, radiation, photon | 1073 | ||||
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A major part of the X-rays generated in the ANKA dipole magnets is unused by the experimental beamlines and is, on a number of dipoles, absorbed in a conical shaped Copper absorber. The 8 mm thickness that it presents lets a tiny fraction of the hard X-rays above 70KeV enter the free air space behind it. The transmitted power of only a few uW/mrad hor. is sufficient to be detected, with sub-second measurement time, by a novel In-Air X-ray detector. This extremely compact and low-cost device is situated just behind the absorber. The design, developed and in use at the ESRF, is based on a Cadmium Tungstenate (CdWO4) scintillator converting X-rays into visible light that is collected and focused onto a commercial CCD camera. Since the small vertical divergence of the high energy photons and the distance of the detector from the source point are known, it is possible to derive the vertical electron beam size with a high intrinsic precision. This paper presents results of beam size measurements as a function of various ANKA machine parameters, that illustrates the great diagnostic potential of this type of detector for a 2.5GeV medium energy light source like ANKA.
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TUPCH033 | Automated Beam Optimisation and Diagnostics at MAMI | diagnostics, microtron, linac, synchrotron-radiation | 1076 | ||||
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At the Institut fur Kernphysik (IKPH) of Mainz University the fourth stage of the Mainz Microtron (MAMI), a 855MeV to 1500MeV Harmonic Double Sided Microtron (HDSM), is now on the verge of first operation*. To provide an automated beam optimisation, low-Q-TM010 and TM110 resonators at each linac of the three cascaded RTMs and the two linacs of the new HDSM are used. These monitors deliver position, phase and intensity signals of each recirculation turn when modulating the beam intensity with 12ns-pulses (diagnostic pulses, max. rep. rate 10kHz). For operating the HDSM an extended system for displaying and digitising these signals was developed. High-bandwidth ADCs allow very comfortable to analyse, calibrate and automatically optimise the beam positions and phases during operation. The system is also used to adjust the transversal and longitudinal focussing according to the design parameters. Synchrotron radiation monitors, providing beam sizes and positions out of the bending magnets for each turn and on the entrance and exit of the linac axis, were a very helpful tool for beam-matching between the RTMs. Therefore a similar system was planned and constructed for the HDSM.
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*A. Jankowiak et al. Status Report on the Harmonics Double Sided Microtron of MAMI C, this conference. |
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TUPCH035 | Fine Spatial Beam Loss Monitoring for the ISIS Proton Synchrotron | dipole, beam-losses, monitoring, acceleration | 1079 | ||||
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Beam loss detection at the ISIS synchrotron is achieved using a series of 3 and 4 metre long argon gas ionisation tubes placed around the inside track of the main ring and along the injector and extraction sections. Even with this level of diagnostics problems have occurred, for example, inside a main dipole within the accelerator ring where small concentrated areas of loss have resulted in severe damage to the RF shield. This type of loss cannot be easily resolved using the conventional argon gas system due to the length of the detectors and their distance from the vacuum vessel (around 2m). We report here the development of a compact beam loss monoitoring system which has been installed inside a dipole between the vacuum vessel and the main body of the dipole. The system comprises of six 150 sq. cm. (BC408) plastic scintillators connected to photo-multiplier tubes via fibre optic bundles. Measurements taken demonstrate that the new system can easily resolve complex beam loss patterns along the dipole while remaining robust to the high radiation environment. We also report here details of our PXI based data collection and display system.
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TUPCH036 | Modelling of Diagnostics for Space Charge Studies on the ISIS Synchrotron | space-charge, ion, simulation, proton | 1082 | ||||
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The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. It is based on a 50 Hz proton synchrotron which, once the commissioning of a new dual harmonic RF system is complete, will accelerate about 3.5·1013 protons per pulse from 70 to 800 MeV, corresponding to mean beam powers of 0.2 MW. Transverse space charge is a key issue for both present and proposed upgrades to the machine, and is the focus of current R&D studies. Experiments on the ISIS ring are central to this work, therefore understanding and quantifying limitations in present and proposed diagnostics is essential. This paper presents work studying and modelling the ISIS residual gas profile monitors, including the effects of non-uniformity in sweep fields, space charge and images. Progress on related work looking at other important diagnostics, e.g., position and envelope monitoring, will also be summarised.
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TUPCH047 | Diamond Optical Diagnostics: First Streak Camera Measurements | injection, electron, storage-ring, DIAMOND | 1112 | ||||
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We present in this paper a first set of measurements of the six-dimensional phase-space of the electron beam in the Diamond storage ring. We recall the predicted performance and compare it with our first measurements. The two pinhole cameras measure the beam size, from which we retrieve the energy spread and the emittance of the beam in both horizontal and vertical directions. We have designed a robust and simple UV-visible beamline, to measure the electron bunch profile and length with a streak camera, and to measure the beam quality using a state-of-the-art single photon counting technique.
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TUPCH054 | Upgrade of Signal Processing of the BPM System at the SPring-8 Storage Ring | target, pick-up, storage-ring, acceleration | 1130 | ||||
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SPring-8 is a third generation synchrotron light source, which is operated stably with top-up mode and with optics of low emittance mode. Along with stabilization of electron beam orbit in the ring, upgrading of the BPM system has also been required. We have developed a new signal processing circuit for COD measurement with a target of a few microns of position resolution at 1 kHz band-width and a few hundreds per second to take beam position of all BPMs. In the new circuit, a multiplexing method is employed and the IF frequency is directory detected with a 2MSPS 16-bit ADC. The digitized signal is processed with DSP to obtain beam position. Analog components of the circuit are equipped in a temperature controlled cabinet in order not to be affected by fluctuation of ambient temperature. In this paper we report schematics and performance of the new circuit, e.g., dependence of position resolution on measurement band-width and long time stability, etc. In addition, we briefly describe possibility of fast orbit measurement as a further application of the circuit.
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TUPCH056 | A Simpler Method for SR Interferometer Calibration | extraction, KEKB, closed-orbit, luminosity | 1136 | ||||
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Previous methods of performing absolute calibration of the SR interferometer used at KEKB (measuring mirror distortion with a pinhole mask, virtual beam broadening via local bumps, physical beam broadening via dispersion bumps) are very time-consuming, and require dedicated machine time to take the necessary data. We report on a new, simpler method we have developed, wherein we create small local bumps at the SR source point and observe the resulting shifts in the phase of the interference fringes. From these data we can calibrate the total magnification of the system, including the effects of mirror distortion. The calibration data can be taken in a very small amount of time (tens of minutes), and in parallel with physics running, without stopping the beam-size measurement system or interfering with its use for luminosity tuning. By taking the calibration data at different beam currents and correlating the magnification at each current with the appropriate interference pattern fit parameters, we can also obtain the parameters needed for real-time mirror distortion correction.
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TUPCH060 | Beam Collimator System in the J-PARC 3-50BT Line | emittance, LEFT, injection, quadrupole | 1148 | ||||
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For the J-PARC 50 GeV Main Ring Synchrotron (MR), the design beam emittance is 54 pi mm mrad. On the other hand, the 3 GeV beam from the Rapid Cycling Booster Synchrotron (RCS) may have a large halo component upto 216 pi mm mrad. In order to absorb the halo component, a beam collimator system will be installed in the beam transport line called as the 3-50BT, which connects the RCS and the MR. From the view of the hands-on maintenance, high endurance structure is adopted. The beam collimator design including the beam optics is reported in this paper.
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TUPCH062 | Synchrotron Radiation Diagnostics for the NSLS Booster | booster, diagnostics, synchrotron-radiation, radiation | 1154 | ||||
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We developed an optical diagnostics system for the NSLS booster-synchrotron utilizing the synchrotron radiation from the dipole magnet. MATLAB based software allows to study the electron beam properties along the energy ramp. The trajectory, beam sizes and coupling at the different instants of time are retrieved from the analysis of the electron beam image. In the paper we present the system layout, as well as experimental results and upgrade plans.
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TUPCH071 | Testing the Silicon Photomultiplier for Ionization Profile Monitor | photon, IPM, CERN, MCP | 1172 | ||||
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A new kind of photonic device is proposed to be used in the fast operating mode of the ionization profile monitor. A silicon photomultiplier device combines the advantages of photomultipliers and solid-state photo detectors. It provides high sensitivity, wide optical spectrum response, high bandwidth and absence of 1/f noise component. Those parameters are critical in the IPM with fast readout feature, which is developing in GSI in collaboration with ITEP, COOSY, MSU and CRYRING laboratories. Very first investigations were made to obtain detailed parameters of silicon photomultiplier. A testing layout and resulting performance data are presented in this publication.
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TUPCH073 | Study of Beam Energy Spread at the VEPP-4M | betatron, diagnostics, collider, scattering | 1178 | ||||
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The knowledge of beam energy spread is necessary for the experimental program of the VEPP-4M collider. In this report we discuss the application of optical diagnostics for measurement of this value. The diagnostics is based on multi-anode photomultiplier and provides information about betatron and betetron frequencies of electron beam*. The beam energy spread is derived from the spectra of synchrotron oscillation. The results, obtained with this method, are compared with data, provided by Compton backscattering technique.
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*O. I. Meshkov et al. Application of the beam profile monitor for VEPP-4M tuning. Proc. of DIPAC '05, June 6 - 8, 2005, Lyon, France, POM008. |
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TUPCH079 | Characterisation of the MAX-II Electron Beam: Beam Size Measurements | optics, electron, synchrotron-radiation, radiation | 1193 | ||||
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Over the last year investigations of the MAX-II electron beam characteristics have been made. Examples of investigated parameters include the beam size, bunch length, vacuum and Touschek lifetimes, and the machine functions. Several upgrades of the MAX II ring have been performed since the commissioning 1995 like a new 100 MHz RF system with a 500 MHz Landau cavity, exchanged injector, and a variety of insertion devices. There is hence a need to systematically characterize the present machine. This systematic characterisation is now underway and this article describes details of the beam size measurements.
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TUPCH083 | Time-resolved Spectrometry on the CLIC Test Facility 3 | electron, radiation, photon, linac | 1205 | ||||
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The high charge (>6microC) electron beam produced in the CLIC Test Facility 3 (CTF3) is accelerated in fully loaded cavities. To be able to measure the resulting strong transient effects, the time evolution of the beam energy and its energy spread must be measured with at least 50MHz bandwidth. Three spectrometer lines were installed all along the linac in order to control and tune the beam. The electrons are deflected by a dipole magnet onto an Optical Transition Radiation (OTR) screen, which is observed by a CCD camera. The measured beam size is then directly related to the energy spread. In order to provide time-resolved energy spectra, a fraction of the OTR photons is sent onto a multichannel photomultiplier. The overall set-up is described, special focus is given to the design of the OTR screen with its synchrotron radiation shielding. The performance of the time-resolved measurements are discussed in detail. Finally, the limitations of the system, mainly due to radiation problems, are discussed.
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TUPCH090 | Electron Beam Profile Measurements with Visible and X-ray Synchrotron Radiation at the Swiss Light Source | emittance, SLS, synchrotron-radiation, radiation | 1223 | ||||
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Two different methods of beam profile measurements using a) visible-to-UV range synchrotron radiation b) X-ray synchrotron radiation have been realized in a single diagnostics beam line at the Swiss Light Source. While the visible-to-UV part uses a focusing lens to create an image of the electron beam cross section, the X-ray part makes use of the pinhole camera principle. In the visible-to-UV case the vertically polarized synchrotron radiation renders an image heavily influenced by inherent emission and diffraction effects of synchrotron radiation. This turns out to be an advantageous influence in order to determine ultra small beam profiles. For each of the two methods practical point-spread function measurements, including all beam line components, and high-precision wave-optics based calculations (SRW code) of the synchrotron light characteristics were performed to ensure correct interpretation of the measured profiles. Results from both monitors will be presented to allow comparison.
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TUPCH095 | Status of Synchrotron Radiation Monitor at TLS | synchrotron-radiation, radiation, controls, booster | 1232 | ||||
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Synchrotron radiation monitor of the Taiwan Light Source have been upgraded recently. Improvement of optics and modelling was performed to improve accuracy of measurement for small beam size. Synchrotron light interferometer is implemented for complementary measurement. IEEE-1394 digital CCD camera is used to improve image transmission quality, camera remote control and to extend dynamic range. Intensify gated camera are included in this upgrade for dynamic property observation of the stored beam. Functionality enhancement of image analysis is also supported. Efforts and achievements will be summarized in this report.
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TUPCH097 | Instrumentation and Operation of a Remote Operation Beam Diagnostics Lab at the Cornell Electron-positron Storage Ring | radiation, optics, positron, electron | 1238 | ||||
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Accelerator beam diagnostics are being modified at the Laboratory of Elementary Particle Physics (LEPP) at Cornell University for remote operation at nearby Alfred University. Presently, a streak camera used for longitudinal dynamics measurements on the Cornell Electron-Positron Storage Ring (CESR) is operational and measurements have been made from Alfred University [1]. In the near future, photomultiplier tube arrays for electron and positron vertical beam dynamics measurements will be remotely operated as well. In this paper, we describe instrumentation and operation of the remote beam diagnostics.
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TUPCH100 | Fiberoptics-based Instrumentation for Storage Ring Longitudinal Diagnostics | radiation, coupling, synchrotron-radiation, diagnostics | 1247 | ||||
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Many beam diagnostic devices in today's synchrotron rings make use of the radiation emitted by the circulating particles. Such instruments are placed in close proximity of the accelerator, where in many instances they cannot be easily accessed for safety consideration, or at the end of a beamline, which because of its cost, can only move the light port a few meters away from the ring. We present a study on the coupling of synchrotron light into an optical fiber for all those application where the longitudinal properties of the beam are measured (i.e., bunch length, phase, intensity, etc.). By choosing an appropriate fiber it is possible to keep attenuation and dispersion at negligible values over a large bandwidth, so that this method would allow to have the diagnostic instruments directly in the control room, or wherever convenient, up to several hundred of meters away from the tunnel. This would make maintaining and replacing instruments, or switching between them, possible without any access to restricted areas. Additionally, the few components required to be near the ring (lenses and couplers) in order to couple the light into the fiber are intrinsically radiation-hard.
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TUPCH120 | The Diamond Light Source Booster RF System | booster, controls, DIAMOND, pick-up | 1295 | ||||
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The Diamond Light Source (DLS) accelerator complex can be divided into three major components; a 3 GeV 561 m circumference storage ring, a 158.4 m circumference full-energy booster synchrotron and a 100 MeV pre-injector linac. This paper describes the design and presents commissioning results of the RF system for the booster synchrotron. Booster RF commissioning took place in late 2005 and early 2006 and involved the setting-into-operation of a 60 kW IOT amplifier, supplied by Thales Broadcast and Multimedia, a 5-cell copper cavity, manufactured by Accel Instruments, and a low-level RF system designed and built by Sincrotrone Trieste SCpA.
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TUPCH124 | Improvement of Co-based Amorphous Core for Untuned Broadband RF Cavity | impedance, acceleration, LEFT, heavy-ion | 1304 | ||||
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We have developed a cobalt-based amorphous core as a new magnetic-alloy (MA) core for the loaded RF cavity. Because of its permeability found to be approximately twice as high as that of FINEMET, this MA core is an excellent candidate for constructing a compact broadband RF cavity with less power consumption. In this report, we present our recent studies of the Co-based amorphous core's physical properties and performance. Improvement of the new core coated by new materials surface of ribbon is also described.
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TUPCH128 | New Cutting Scheme of Magnetic Alloy Cores for J-PARC Synchrotrons | DIAMOND, acceleration, KEK, beam-loading | 1313 | ||||
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A new cutting method using a grindstone was developed to manufacture the magnetic alloy cores. The problem of local temperature rise around the cut surfaces was solved. Long-term high-power tests have been performed for both J-PARC RCS and MR RF systems. Mechanism of local heating, new cutting scheme, and manufacturing method are presented.
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TUPCH129 | Conceptual Design of a 3rd Harmonic Cavity System for the LNLS Electron Storage Ring | electron, storage-ring, damping, CBM | 1316 | ||||
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The installation of a second RF cavity in the UVX electron storage ring at the Brazilian Synchrotron Light Laboratory (LNLS) at the end of 2003 brought about longitudinal instabilities driven by one of the HOMs of the new cavity. Even though the operational difficulties related to these unstable modes were successfully overcome by means of a combination of cavity tuning (using temperature and plunger adjustments) with phase modulation of the RF fields at the second harmonic of the synchrotron frequency, a more appropriate technique to avoid those problems is the use of higher harmonic cavities, which have the important advantage of providing damping of the longitudinal modes without increasing the energy spread, i.e., without compromising the longitudinal emittance. In this work we present the design of a passive higher harmonic cavity system optimized for operation at the LNLS storage ring. The parameters for a set of cavities as well as the analysis of some of the effects that they may introduce in the beam dynamics are presented. An overview of the technical aspects related to the project, construction and installation of the cavities in the storage ring is also presented.
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TUPCH131 | High Power Test of MA Cavity for J-PARC RCS | impedance, proton, acceleration, power-supply | 1322 | ||||
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We have been constructing the RF system for the J-PARC RCS. Almost all of the power supplies and the tube amplifiers have been constructed, and the cavities are under construction. All of them are tested at the experimental hall before installing into the J-PARC RCS building. We test the hybrid cavity scheme to realize the optimum cavity Q-value. The results of the test are described.
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TUPCH132 | Higher Order Mode (HOM) Damper of 500 MHz Damped Cavity for ASP Storage Ring | coupling, insertion, storage-ring, damping | 1325 | ||||
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TOSHIBA has delivered the storage ring RF system for the Australian Synchrotron Project(ASP). Two pairs of the 500MHz Higher Order Mode(HOM) damped cavities were applied for this system. Two on-centered and one off-centered dampers were attached for damping the longitudinal HOM impedance down to less than 20kOhm/GHz. In order to reduce the coupling of off-center damper for accelerating mode and improve cooling power of damper, New HOM damper was designed by optimizing SiC absorber structure and damper antenna length using HFSS code. The design and manufacture of the new HOM damper and the test are described.
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TUPCH141 | New Developments for the RF System of the ALBA Storage Ring | simulation, storage-ring, insertion, klystron | 1346 | ||||
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ALBA is a 3 GeV, 400 mA, 3rd generation Synchrotron Light Source that is in the construction phase in Cerdanyola, Spain. The RF System will have to provide 3.6 MV of accelerating voltage and restore up to 540 kW of power to the electron beam. For that six RF plants, working at 500 MHz, are foreseen. The RF plants will include several new developments: 1) DAMPY cavity: the normal conducting HOM damped cavity developed by BESSY and based in the EU design; six will be installed. 2) CaCo: A cavity combiner to add the power to two 80 kW IOTs to produce the 160 kW needed for each cavity. 3) WATRAX: A waveguide transition to coaxial, specially designed to feed the DAMPY cavities due to the geometrical and cooling constrains. 4) IQ LLRF: The low level RF will be based on the IQ modulation/demodulation technique, both analogue and digital approach are being pursued. This paper describes the Storage Ring RF System and reports about the status of these new developments.
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TUPCH150 | Improved 1.3 GHz Inductive Output Tube for Particle Accelerators | ERLP, linac, klystron | 1373 | ||||
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There is an increasing requirement for RF power sources in the L-band frequency range for operation in particle accelerators. Previously (at PAC 2005), the design, development and initial testing of a new L-band 16kW cw inductive output tube (IOT) was described. This paper discusses the detailed performance characteristics of the latest EEV IOT116LS embodying the most recent design improvements and presents data demonstrating its suitability for operation at 1.3GHz in the next generation of light sources.
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TUPCH178 | Deposition of Non Evaporable Getter (NEG) Films on Vacuum Chambers for High Energy Machines and Synchrotron Radiation Sources | vacuum, cathode, electron, controls | 1435 | ||||
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Non Evaporable Getter (NEG) films, sputter deposited onto the internal surfaces of vacuum chambers reduce thermal out-gassing and provide conductance-free distributed pumping ability, allowing the achievement of very low pressure inside narrow and conductance limited chambers, like Insertion Devices. NEG films do show additional interesting features, like low secondary electron yield and low gas de-sorption rates under ions, electrons and photons bombardment. They seem therefore ideal to reduce electron multi-pacting and dynamic gas de-sorption induced beam instabilities in high energy machines. This paper presents SAES getters experience in the NEG coating of chambers of different geometries and sizes for a variety of projects related to high energy machines and synchrotron radiation facilities. Examples of applications, as well as most common issues related to chambers preparation, film deposition, characterization and quality control, are given. Areas where further work is still necessary to fully take advantage of NEG film properties will be also discussed.
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TUPCH193 | Low Level RF Control System Modules for J-PARC RCS | controls, acceleration, simulation, dipole | 1465 | ||||
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After completing the design phase, the VME modules for the Low Level RF Control (LLRF) of the Rapid Cycling Synchrotron of J-PARC are now in the production and debugging phase. First all modules are tested for basic functionality, for example dual harmonic signal generation. Then sets of modules are connected together to check higher-level functions and feedback. Finally, the LLRF modules are interfaced to high voltage components like amplifiers and cavities. We present the results of these tests, the test methods and test functions on several levels. This way we simulate beam operation working conditions and gain experience in controlling all parameters.
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TUPCH194 | Analogue and Digital Low Level RF for the ALBA Synchrotron | controls, resonance, shielding, linac | 1468 | ||||
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ALBA is a 3 GeV, 400 mA, 3rd generation Synchrotron Light Source that is in the construction phase in Cerdanyola, Spain. The RF System will have to provide 3.6 MV of accelerating voltage and restore up to 540 kW of power to the electron beam. Two LLRF prototypes are being developed in parallel, both following the IQ modulation/demodulation technique. One is fully based on analogue technologies; the other is based on digital FPGA processing. The advantages of the IQ technique will be summarised and the control loop logic described. The hardware implementation in analogue as well as in digital format will be presented and first test results shown. The implementation of the same logic with both technologies will give us a perfect bench to compare, and use the better of them, for the final LLRF of the ALBA synchrotron.
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TUPLS053 | Beam Dynamics of a High Current IH-DTL Structure for the TWAC Injector | rfq, ion, emittance, quadrupole | 1615 | ||||
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A powerful ion injector based on a laser ion source is needed for an efficient operation of the Tera Watt Accumulator (TWAC) complex including a heavy ion synchrotron and a storage ring, which is under progress now at ITEP, Moscow. The Interdigital H-type drift tube linac (IH-DTL) structure operating at 162 MHz is proposed for the second stage of the injector linac behind of a 81 MHz RFQ. Consisting of independently driven sections with inter-tank quadrupole triplet focusing, this structure will accelerate highly stripped ions with charge-to-mass ratios above 1/3 in the energy range from 1.57 MeV/u at the RFQ exit to 7 MeV/u. Beam currents up to 100 mA are expected for medium ions like Carbon or Aluminum. Since the rf frequency is duplicated at the entrance of the IH-DTL in order to reduce size as well as power consumption, space charge effects are dominant at full current. Beam dynamics and structure parameters are discussed in detail.
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TUPLS087 | Recent Gains in Polarized Beam Intensities for the Cooler Synchrotron COSY at Jülich | COSY, ion, cyclotron, ion-source | 1705 | ||||
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Since January 1996, the cyclotron JULIC operates as the injector of H(-) or D(-) beams for the cooler synchrotron COSY at the IKP of the Forschungszentrum Juelich. Routinely about 8 microA of unpolarized or 1 microA of polarized H(-) ions are delivered for charge-exchange injection into COSY. A polarization in excess of 90 % was measured for protons inside the synchrotron COSY. Additionally, polarized and unpolarized D(-) ions have been delivered to experiments. A sequence of up to eight different polarization states for deuterons has been provided for experiments. By advancing the components of the polarized ion the number of polarized particles for injection into the cyclotron has been increased by a factor of three to 5,5x1012 protons, delivered in a 20 ms pulse with a repetition rate of 2 seconds. This report sums up the characteristics of the ion sources and the cyclotron in their present mode of operation and describes the achievements towards higher beam intensities as well as for providing unpolarized and polarized H(-) and D(-) beams with high reliability.
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TUPLS106 | Pulsed Bending Magnet of the J-PARC MR | power-supply, TESLA, simulation, KEK | 1747 | ||||
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Japan Proton Accelerator Research Complex (J-PARC) is under construction with a collaboration between Japan Atomic Energy Agency (JAEA) and High Energy Accelerator Research Organization (KEK). The J-PARC consists of a 180 MeV linac, a 3 GeV rapid-cycle synchrotron (RCS) and a 50 GeV synchrotron (MR). The bunch trains, which extracted from the RCS, is delivered both to the Materials and Life Science Facility and to the MR, two beam transport lines, 3-NBT and 3-50BT, are constructed. The switching of bunch trains is performed by a pulsed bending magnet. The field strength of 1.21 Tesla with rise and fall time of less than 40 msec is required. It was found that an effect induced by eddy current, which flows at thick end-plates, disturbs the flatness of the magnetic field. A simple compensation circuit has been adopted for a cure. A result from a field measurement, which shows a sufficient flatness, is presented.
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TUPLS137 | Design of the Utility System for the 3 GeV TPS Electron Storage Ring | storage-ring, controls, booster, synchrotron-radiation | 1828 | ||||
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After 13-year operation of the Taiwan Light Source (TLS), National Synchrotron Radiation Research Center (NSRRC), had proposed to construct a new light sourc, Taiwan Photon Source (TPS) in the near future. TPS is preliminarily designed with 3.0 GeV in energy, 518.4m in circumference and 24 Double-Bend Achromat (DBA). This study designed the utility system, including the electrical power system, grounding system, de-ionized cooling water (DIW) system and air conditioning (AC) system for the TPS. Special considerations are focused on the stability of the electrical power and grounding system and temperature control of the DIW and AC systems. The power and cooling loads had been estimated according to each subsystem of the accelerator. Layouts of main utility equipment and piping system had also been preliminarily designed.
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WEOFI02 | RF Phase Modulation Studies at the LNLS Electron Storage Ring | damping, single-bunch, electron, storage-ring | 1905 | ||||
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In this work we present a set of measurements of the effectiveness of RF phase modulation on the second harmonic of the RF frequency as a mechanism to damp longitudinal coupled-bunch instabilities. We also propose a theoretical model of the damping mechanism, in which the increase of the spread in synchrotron frequencies inside the bunches produced by phase modulation is responsible for damping the centroid dipolar coherent motion caused by an external excitation, which could be a Higher Order Mode (HOM) of the RF cavities driving the coupled bunch motion. We measured the coherent synchrotron oscillation damping of a single bunch under two circumstances, with and without phase modulation, and determined the amount of extra damping due to the modulation. With this experiment we could also measure the frequency of small oscillations around the stable islands formed by phase modulation and its behavior when the RF phase modulation amplitude and frequency are changed. We performed measurements of Beam Transfer Function (BTF) to observe the effects of phase modulation over the stable area for coherent oscillations and compared the results with a theoretical model.
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Transparencies
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WEOFI03 | Beam Dynamics Simulation in e- Rings in SRFF Regime | CSR, simulation, vacuum, lattice | 1908 | ||||
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The concept of strong RF focusing has been recently proposed to obtain locally short bunches in electron/positron colliders, by modulating the longitudinal bunch dimensions along the rings. To study the single bunch dynamics, a macroparticle numerical code has been written which simulates the effects of the objects generating broad band impedance along the ring and the effects of the coherent synchrotron radiation in dipoles and wigglers. The obtained results are shown and discussed.
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Transparencies
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WEIFI01 | How to Create a Business out of Manufacturing Linacs | linac, proton, ion, cyclotron | 1911 | ||||
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AccSys Technology, Inc. was established in 1985 by the author and several colleagues to sell ion linacs based on the new linac technology that had just been developed at the Los Alamos National Laboratory. The company is now the leading manufacturer of turn-key ion linacs for several markets worldwide. This paper will describe the history of AccSys and how it has survived more than 20 years manufacturing these specialized products. The similarities of AccSys' history to that of a small electron linac manufacturer established in 1970 will also be described to provide a general concept of what is required to create a business out of manufacturing linacs.
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Transparencies
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WEPCH005 | Advances in Beam Orbit Stability at the LNLS Electron Storage Ring | storage-ring, vacuum, radiation, shielding | 1924 | ||||
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We describe recent efforts made at the Brazilian Synchrotron Light Source (LNLS) to improve beam orbit stability. The main driving force is the high positional stability required by some specific experiments and particularly by a high resolution undulator beamline which is being built at LNLS. Recent steps taken to improve orbit stability include the development of x-ray BPMs to measure the vertical position of the x-ray beam, analysis of RF BPM movement due to thermal load induced by synchrotron radiation after injection, new algorithms to deal with BPM electronics or control board false readings and revision and modification of their installations. In addition a weighted least squares method was developed to account for global correction while simultaneously privileging some local source point position. These upgrades are part of an ongoing work to improve beam orbit stability at LNLS.
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WEPCH013 | Electron Transport Line Optimization using Neural Networks and Genetic Algorithms | injection, booster, electron, storage-ring | 1948 | ||||
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Methods of computational intelligence (CI) were investigated to support the optimization of the electron transfer efficiency from the booster synchrotron BoDo to the electron storage ring DELTA. Neural networks and genetic algorithms were analysed alternatively. At first both types of methods were trained on the basis of a theoretical model of the transport line. After the training various algorithms were used to improve the magnet settings of the real transport line elements with respect to the electron transfer efficiency. The results of different strategies are compared and prospects as well as limitations of CI-methods to the application of typical optimization problems in accelerator operation are discussed.
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WEPCH023 | Longitudinal Coherent Oscillation Induced in Quasi-isochronous Ring | power-supply, electron, storage-ring, closed-orbit | 1972 | ||||
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Noise sources, which excite longitudinal coherent oscillation is discussed. Especially in a quasi-isochronous electron storage ring an identification of the noise sources is important to obtain an extremely short bunch. One possible source is a well-known rf noise in the acceleration field. The other is a magnetic field ripple, which changes a path-length for a revolution. The analytical formula for the longitudinal coherent oscillation is explained. It contains the path-length oscillation, which had never been considered. The third is a beam itself, probably be a coherent radiation loss. The driving term is not symmetric along the energy axis, then the oscillation amplitude depends on the higher order momentum compaction factor.
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WEPCH041 | Analytic Study of Longitudinal Dynamics in Race-track Microtrons | longitudinal-dynamics, injection, electron, microtron | 2008 | ||||
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Implementation of low energy injection schemes in the race-track microtron (RTM) design requires a better understanding of the longitudinal beam dynamics. Differently to the high energy case a low-energy beam will slip in phase relative to the accelerating structure phase. We generalize the concept of equilibrium or synchronous particle for the case of non-relativistic energies and introduce the notion of transition energy for RTMs. An analytical approach for the description of the synchronous phase slip is developed and explicit, though approximate, formulas which allow to define the equilibrium injection phase and fix the parameters of the accelerator are derived. The approximation can be improved in a systematic way by calculating higher order corrections. The precision of the analytical approach is checked by direct numerical computations using the RTMTrace code and was shown to be quite satisfactory. Explicit examples of injection schemes and fixing of RTM global parameters are presented.
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WEPCH049 | Closed Orbit Correction of TPS Storage Ring | closed-orbit, dipole, quadrupole, emittance | 2029 | ||||
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A 3 GeV synchrotron storage ring is proposed in Taiwan to serve the synchrotron light users, especially for the x-ray community. The ring consists of 24 double-bend cells with 6-fold symmetry and the circumference is 518.4 m. The designed natural emittance with slightly positive dispersion in the straight sections is less than 2 nm-rad. This low emittance lattice structure needs strong quadrupoles and sextupoles and the closed orbit distortions are sensitive to the alignment errors in the quadrupoles and sextupoles as well. The closed orbit distortions due to tolerable magnetic errors are simulated and the correction scheme is proposed. Using singular value decomposition method, the closed orbit distortions are corrected and corrector strengths as well as the residual closed orbit distortions are obtained.
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WEPCH065 | Lattices for High-power Proton Beam Acceleration and Secondary Beam Collection, Cooling, and Deceleration | lattice, secondary-beams, proton, dipole | 2074 | ||||
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Rapid-cycling synchrotrons are used to accelerate high-intensity proton beams to energies of tens of GeV for secondary beam production. After primary beam collision with a target, the secondary beam can be collected, cooled, accelerated or decelerated by ancillary synchrotrons for various applications. In this paper, we first present a lattice for the main synchrotron. This lattice has: a) flexible momentum compaction to avoid transition and to facilitate RF gymnastics b) long straight sections for low-loss injection, extraction, and high-efficiency collimation c) dispersion-free straights to avoid longitudinal-transverse coupling, and d) momentum cleaning at locations of large dispersion with missing dipoles. Then, we present a lattice for a cooler ring for the secondary beam. The momentum compaction across half of this ring is near zero, while for the other half it is normal. Thus, bad mixing is minimized while good mixing is maintained for stochastic beam cooling.
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WEPCH086 | Adiabatic Theory of Slow Extraction of Particles from a Synchrotron | resonance, extraction, betatron, heavy-ion | 2119 | ||||
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An analytical approach is developed to describe the process of slow extraction of particles from a synchrotron based on adiabatic crossing of the betatron resonance of the third order. An exact expression for the phase integral is found to analyze the conditions of oscillation amplitude growth near the resonance band. It allows one to directly define the interval of adiabatic motion from the start of decreasing the resonant tune to the beginning of fast increase of the oscillation amplitude. The interval distribution function is constructed for the cases of zero momentum spread and zero machine chromaticity as well as for the general case, taking into account non-zero momentum spread, non-zero chromaticity and synchrotron oscillations. Some numeric calculations of the time dependence of the extracted particle current are presented. It is shown that the momentum spread in the extracted beam can be minimized with the use of additional RF acceleration of particles during the slow extraction procedure.
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WEPCH097 | Beam Dynamics in Compton-ring Gamma Sources | laser, electron, emittance, simulation | 2143 | ||||
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Electron storage rings with a laser cavity are promising intensive sources of polarized hard photons to generate polarized positron beams. The dynamics of electron bunches circulating in a storage ring and interacting with high-power laser pulses is studied both analytically and by simulation. Common features and difference in the bunch behavior interacting with an extremely high power laser pulse (polarized positron source for the ILC project) and a moderate pulse (source for CLIC) are shown. Also considerations on particular lattice designs for both rings are presented.
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WEPCH128 | Virtual Accelerator as an Operation Tool at J-PARC 3 GeV Rapid Cycling Synchrotron (RCS) | betatron, simulation, optics, feedback | 2224 | ||||
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We developed a virtual accelerator based on EPICS for 3 GeV Rapid-Cycle Synchrotron (RCS) in J-PARC. It is important to have an on-line model of optics parameters, such as tunes, Twiss parameters, dispersion function, at the commissioning stage in a high intensity proton machine. It gives a strong feedback for the RCS operation as a commissioning tool as well as for the studies of beam dynamics issues. Beam position monitors with finite resolutions, a transverse exciter to measure the betatron frequency, and a RF system with variable frequency to simulate off-momentum optics have been implemented into the system. The virtual accelerator system itself and some results of beam dynamics studies will be presented.
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WEPCH157 | Design and Beam Dynamics Simulation for the Ion-injector of the Austrian Hadron Therapy Accelerator | ion, simulation, proton, extraction | 2296 | ||||
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MedAustron is an initiative for the construction of the Austrian Hadron Therapy Centre. In 2004 the design study was presented. The basic design consists of two ion sources, an ion-injector, a synchrotron and a beam transfer line with five possible beam exits. The synchrotron is based on the proton ion medical machine study (PIMMS) design with some modifications. The injector is based on the GSI design of the Heidelberg ion therapy cancer accelerator with the original radio frequency quadrupole and IH-Linac. Modifications have been done in the design of the low energy beam transport and the medium energy beam transport lines. The impact of these modifications has been investigated, and several other beam scenarios have bean simulated with different simulation codes.
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WEPCH159 | Accelerator Systems for Particle Therapy | ion, proton, GSI, beam-transport | 2302 | ||||
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Danfysik and Siemens have entered a cooperation to market and build Particle Therapy* systems for cancer therapy. The systems are based on the experience from GSI together with a novel design of a synchrotron and Siemens experience in oncology. The accelerator systems will include an injector system (7 MeV/u proton and light ions), a synchrotron and a choice of fixed-angle horizontal and semi-vertical beamlines together with gantry systems. The slowly extracted beam will cover the energy ranges of 48-250 MeV for protons and 88-430 MeV/u for carbon ions. The extraction time will be up to 10s with intensities well beyond the needs of scanning beam applications. We will describe the layout of such a system and present details on some of the subsystems.
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*Particle Therapy is a work in progress and requires country-specific regulatory approval prior to clinical use. |
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WEPCH160 | A Novel Proton and Light Ion Synchrotron for Particle Therapy | extraction, septum, dipole, injection | 2305 | ||||
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A compact and simple synchrotron for a cancer particle therapy system has been designed and is presently under construction. A lattice with six regular superperiods, twelve dipole and twelve quadrupole magnets, is used. The optimized lattice configuration, including the design of injection and extraction systems, provides large transverse phase space acceptance with minimum magnet apertures. The result is a synchrotron for PT with light magnets (5t dipoles), low values of peak power for pulsed operation and minimum dc power consumption. In addition, industrial production principles are used, keeping ease of construction, installation, and operation in mind. The beam, injected at 7 MeV/amu, can be accelerated to the maximum magnetic rigidity of 6.6 Tm in less than 1 s. A beam of 48-250 MeV protons and 88-430 MeV/u carbon ions can be slowly extracted during up to 10s. The intensity for protons and carbon ions will be well beyond the needs of scanning beam applications. The design and performance specifications of the synchrotron will be described in detail.
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WEPCH161 | The FFAG R&D and Medical Application Project RACCAM | lattice, proton, acceleration, electron | 2308 | ||||
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The RACCAM project (Recherche en ACCelerateurs et Applications Medicales) has recently obtained fundings, extending over three years (2006-2008), from the French National Research Agency (ANR). RACCAM is a tripartite collaboration, involving (i) the CNRS Laboratory IN2P3/LPSC, (ii) the French magnet industrial SIGMAPHI, and (iii) the nuclear medecine Departement of Grenoble Hospital. The project concerns fixed field alternating gradient accelerator (FFAG) research on the one hand, and on the other hand their application as hadrontherapy and biology research machines. RACCAM's goal is three-fold, (i) participate to the on-going international collaborations in the field of FFAGs and recent concepts of "non-scaling" FFAGs, with frames for instance, the Neutrino Factory (NuFact) and the EMMA project of an electron model of a muon FFAG accelerator, (ii) design, build and experiment a prototype of an FFAG magnet proper to fulfil the requirements of rapid cycling acceleration, (iii) develop the concepts, and show the feasibility, of the application of such FFAG beams to hadrontherapy and to biology research.
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*CEA/DAPNIA and IN2P3/LPSC **IN2P3/LPSC ***Grenoble University Hospital ****SIGMAPHI |
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WEPCH167 | Study of Scatterer Method to Compensate Asymmetric Distribution of Slowly Extracted Beam at HIMAC Synchrotron | scattering, simulation, extraction, emittance | 2322 | ||||
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In the medical use of the ion beam, the following characteristics of the beam are preferred: 1) Symmetric Gaussian beam profile is convenient for the scanning irradiation. 2) In the rotating gantry system, the symmetric beam condition can realize no-correlation between the beam profiles and the rotation angles of the gantry. However, the slowly extracted beam has asymmetric distribution in the phase-space and a difference between the horizontal emittance and vertical one. Thus, we have proposed the thin scatterer method to compensate the phase-space distribution of the slowly extracted beam, although the emittance is enlarged by scattering. As a result of particle tracking and experiment, it was verified that the asymmetric distribution was compensated by very small scattering angle. It was also simulated that this scatterer method can realize the symmetric beam condition for the rotating gantry. In this paper, these results of asymmetry compensation for the slow-extraction at HIMAC is presented.
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WEPCH170 | Development of Intensity Control System with RF-knockout Extraction at the HIMAC Synchrotron | controls, extraction, ion, heavy-ion | 2331 | ||||
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We have developed a dynamic intensity control system toward scanning irradiation at the HIMAC Synchrotron. In this system, for controlling the spill structure and intensities of the beams extracted from the synchrotron, the amplitude of the RF-knockout is controlled with the response of 10 kHz. Its amplitude modulation (AM) function is generated based on an analytical one-dimensional model of the RF-knockout slow-extraction. In this paper, we describe the system for controlling amplitude modulation including feedback and the experimental result.
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WEPLS022 | ILC Beam Energy Measurement based on Synchrotron Radiation from a Magnetic Spectrometer | photon, radiation, electron, synchrotron-radiation | 2442 | ||||
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The magnetic spectrometer with a relative energy resolution of 5·10-5 was proposed for ILC beam energy measurements. The beam energy measurement is based on precise definition of the beam position at a resolution of 100 nm and B-field integral at an accuracy of 2E-5. A complementary method of the beam energy measurement is proposed at registration of synchrotron radiation (SR) from the energy spectrometer dipole magnets. The measurements of both edge horizontal positions for SR fan on a distance of 50-70 m downstream of the spectrometer magnets permit to determine the beam energy with required resolution. The main principles of the beam energy measurements based on SR, the numerical simulations of SR performed by the GEANT code and proposal of SR monitors with submicron resolution are discussed.
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WEPLS032 | Spin Tracking at the ILC | damping, polarization, positron, radiation | 2454 | ||||
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Polarized beams will play a key role in the physics programme at the International Linear Collider (ILC). It is expected that the electron and positron sources will be able to produce beams with polarizations of about 90% and 60% respectively. However, to obtain accurate measurements it is essential to have precise knowledge and control of the polarization at the interaction point itself. It follows that the theoretical calculations used for spin tracking must be guaranteed to match the anticipated 0.1% relative measurement uncertainty of the polarimeters. To meet this need, the heLiCal collaboration is developing a computer simulation to track the evolution of the polarization of bunches of electrons and positrons from the sources to the interaction point. We have studied the beam spin dynamics throughout the ILC including spin precession and radiative spin-flip processes in the positron source, damping rings, beam delivery system and the interaction region. We present the result of these studies with special emphasis on the impact of new theoretical calculations for the CAIN bunch-bunch simulation including full spin correlations and higher-order contributions.
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WEPLS056 | R&D Status of the High-intense Monochromatic Low-energy Muon Source: PRISM | simulation, impedance, lepton, focusing | 2508 | ||||
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PRISM is a project of a future intense low-energy muon source, which combines monochromaticity and high purity. Its aimed intensity is about $1011-1012 muons per second. The muon beams will have a low kinetic energy of 20MeV so that it would be optimized for the stopped muon experiments such as searching the muon lepton flavor violating processes. PRISM consists of a pion capture section, a pion/muon transfer section and a phase rotation ssection. An FFAG is used as the phase rotator to achieve the monochromatic muon beams. This paper will describe design status of these sections as well as construction status of PRISM-FFAG.
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WEPLS084 | AC Field Measurements of Fermilab Booster Correctors Using a Rotating Coil System | booster, dipole, sextupole, quadrupole | 2574 | ||||
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The first prototype of a new corrector package for the Fermilab Booster Synchrotron is presently in production. This water-cooled package includes normal and skew dipole, quadrupole and sextupole magnets to control orbit, tune and chromaticity of the beam over the full range of Booster energies (400 MeV-8 GeV). These correctors must make rapid excursions from the 15 Hz excitation cycle of the main synchrotron magnets, in some cases even switching polarity in approximately 1 ms at transition crossing. To measure the dynamic changes in the field during operation, a new method based on a relatively slow rotating coil system is proposed. The method pieces together the measured flux from successive current cycles to reconstruct the field harmonics. This paper describes the method and presents initial field quality measurements from the corrector prototype.
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WEPLS090 | Full Length Superferric Dipole and Quadrupole Prototype Magnets for the SIS100 at GSI: Status of the Design and Manufacturing | dipole, quadrupole, GSI, ion | 2583 | ||||
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The SIS100, one of the two basic accelerators of the future Facility for Antiproton and Ion Research FAIR at GSI, should provide acceleration of U28+ and proton beams for 0.5 s with a pulse repetition rate of 1 Hz. In the accelerator magnetic system superferric 2 T dipoles of about 3 m length and 35 T/m quadrupoles of about 1 m length will be used. The magnet coils are made from hollow NbTi composite cable cooled with two-phase helium flow at 4.5 K. The maximum operating current of 7500 A is supposed. The lattice comprises 108 dipoles and 168 quadrupoles. The elliptic beam pipe inner sizes have been fixed to 130x60 mm2 for the dipole and 135x65 mm2 for the quadrupole The design approach is based on the improved versions of the Nuclotron fast-cycling magnets that provide significant less AC loss at 4.5 K, better quality of the magnetic field and a higher long-term mechanical stability of the magnet coils. The AC losses in the magnets for the strongest SIS100 operating cycle at 4.5 K are expected to be about 13 W/m and 17 W/m in the full length prototype dipole and quadrupole magnets respectively.
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WEPLS091 | Analysis of the Superferric Quadrupole Magnet Design for the SIS100 Accelerator of the FAIR Project | quadrupole, GSI, dipole, ion | 2586 | ||||
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The heavy ion fast-cycling synchrotron SIS100 is the "workhorse", of the future Facility for Antiproton and Ion Research FAIR at GSI in Darmstadt. The main lattice parameters of the accelerator are defined now so the main engineering problems of the new superferric magnets should be analyzed and solved too. We present the results of finite element calculations and compare them with the experimental data from investigation of the model magnets to characterize the expected AC loss properties of the full length prototype quadrupole. We discuss the appropriate new coil structure aimed at minimizing the heat releases at 4.5 K, but providing the requested long-term mechanical stability against dynamic Lorentz forces and thermal cooling cycles as well.
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WEPLS094 | 3D Magnetic Field and Eddy Current Loss Calculations for Iron Dominated Accelerator Magnets using ANSYS Compared with Results of Noncommercial Codes | GSI, simulation, dipole, quadrupole | 2595 | ||||
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The design of fast ramped superferric magnets with repetition rates in the order of 1Hz requires reliable software tools to calculate the complex 3D magnetic field quality as well as the impact of eddy current and hysteresis loss. Various technological construction details should be taken into account to obtain a high field quality. We present a methodical study of these questions based on ANSYS calculations for simplified dipole models. The details of these analysis are compared with recently published results obtained by different special codes, i.e. an integral and the FIT method. The time dependences of eddy current power due to longitudinal magnetic field component at the yoke ends, the transient field distribution in the yoke volume and the total eddy current loss are investigated, choosing the identical geometry with the same magnetic and electric properties of the lamination steel used by the other codes. The conclusions for the application potential of the different methods are discussed.
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WEPLS118 | The 3Hz Power Supplies of the SOLEIL Booster | dipole, booster, SOLEIL, power-supply | 2652 | ||||
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SOLEIL is a 2.75 GeV new third generation synchrotron radiation facility under construction near Paris. The injector system is composed of a 100 MeV electron Linac pre-accelerator followed by a full energy (2.75 GeV) booster synchrotron. A repetition rate of 3Hz is required for the booster for the filling of the Storage Ring together with the need for discontinuous operation for top-up filling mode. Based on digital regulation loop, the four power supplies (2 for the dipoles 600 A x 1000 V and 2 for the quadrupoles 250 A x 450 V) reach the current tracking tolerance specification of 10-3. The aim of this paper is to describe the main issues from the loads to the mains network through the power converters that are essential to reach the required performances.
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WEPLS127 | CNAO Storage Ring Dipole Magnet Power Converter 3000A / ±1600V | controls, power-supply, dipole, simulation | 2673 | ||||
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This paper will describe the design and simulations of the CNAO Dipole Power Converter rated 3000A / ±1600V. The Power Converter will feed the 16+1 synchrotron bending dipole magnets of the CNAO Storage Ring. The actual design confirms how the choice of a 24-pulses, 4 bridges series-parallel connected, active filter, bipolar voltage, meets the stringent requested technical specification ( 10-5 of maximum current for the output current residual ripple and setting resolution). The extensive modelling will also be presented. The design includes the strength of the topology design, component de-rating and component standardisation. As the other CNAO power converters, the Storage Ring Dipole Power Converter uses the same digital controller, under licence from the Diamond Light Source.
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WEPLS128 | The Italian Hadrontherapy Center (CNAO): A Review of the Power Supply System for Conventional Magnets | dipole, power-supply, quadrupole, controls | 2676 | ||||
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A hadron (Carbon/Proton) medical centre based on a synchrotron accelerator dedicated to the cure of deep tumours is under construction in Pavia (Italy) under the joint responsibility of CNAO (Centro Nazionale di Adroterapia Oncologica) and INFN (Istituto Nazionale di Fisica Nucleare). This paper describes the power supply system, made up of about 200 units designed by LNF, and whose converters for the synchrotron ring and related low, medium and high energy transfer lines are now under construction by the major Italian companies. The power supplies requirements and electrical characteristics will be reported describing the most interesting topologies that fulfill the requested performances together with the main features of each power supply topology. Synchrotron dipoles, quadrupoles, sextupoles and resonance sextupole power supplies have tight characteristics with respect to precision class (current resolution, residual ripple, short-long term stability, etc.) that range from 5 ppm to 500 ppm, fast dynamical response with bandwidth up to some hundreds hertz, high power from tens of kW to many MW and output current ranging from hundreds of A to 3 kA.
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WEPLS129 | Upgrade Scheme for the J-PARC Main Ring Magnet Power Supply | power-supply, KEK, linac, extraction | 2679 | ||||
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Japan Proton Accelerator Research Complex (J-PARC) is under construction at the Tokai campus of Japan Atomic Energy Agency (JAEA) as a joint project between KEK and JAEA. The accelerator complex, which is constructed as a 200 MeV linac, a 3 GeV RCS synchrotron, and a main ring in phase I. The main ring magnet power supply is constructing as the energy of 40 GeV in phase I and will upgrade up to 50 GeV in phase II. A large amount of pulse electric power, which is + 115 MW and -55 MW peak-to-peak, is required for 50 GeV operation and this large pulse power will give unallowable disturbances to a power network. In order to compensate the disturbances to allowable level, we need some energy storage system. A SMES system will be one of the promising means for the purposes as well as the fly-wheel system. We will describe some energy storage system and also the increasing of repetition rate without energy storage system.
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WEPLS135 | Piezoelectric Transformer Based Continuous-conduction-mode Voltage Source Charge-pump Power Factor Correction Electronic Ballast | APR, synchrotron-radiation, radiation | 2694 | ||||
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This paper presents the piezoelectric transformer (PT) based continuous-conduction-mode (CCM) voltage source (VS) charge-pump (CP) power factor correction (PFC) electronic ballast. By replacing L-C resonant tank and transformer in the conventional CCM VS CP PFC electronic ballast with PT, the cost and volume can be reduced. The main drawback of conventional electronic ballast is that the input current has a narrow conduction angle, which causes rich harmonic that pollute the power system. However, the conventional CCM VS CP PFC electronic ballast is able to solve this problem but still require larger volume. Since the equivalent circuit of PT is identical to the conventional L-C resonant tank used in CCM VS CP PFC electronic ballast, the L-C resonant tank can be replaced by the PT to reduce the cost and volume. In addition, the inherent input capacitance of the PT works as a turn-off snubber for the power switches to decrease the turn-off voltage spikes and thus reduces the turn-off losses of the switches. The results show that the electronic ballast using PT achieved high power factor and the switches can be operated under ZVS condition.
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THOAFI02 | Ion Instability Observed in PLS Revolver In-vacuum Undulator | vacuum, undulator, ion, radiation | 2771 | ||||
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Revolver In-Vacuum X-ray Undulator which was designed and fabricated at Spring-8 is under commissioning at PLS. This planar undulator whose permanent magnet array structure is a revolving type with 90-degree step provides 4 different undulator wavelengths of 10, 15, 20, and 24 mm. The minimum gap of the undulator is as small as 5 mm. It was observed that the trailing part of a long bunch train was scraped due to ion instability when the undulator gap was closed below 6 mm. At that time the vacuum pressure in the undulator, which is estimated to be about one order of magnitude lower than that of the undulator gap, increased from 1.4 x 10-10 (gap 20 mm) to 7.9 x 10-10 Torr (gap 6 mm) at the stored beam current of 100 mA. This high vacuum pressure causes fast beam-ion instability: trailing part of a long bunch train oscillates vertically. It was also confirmed that adjusting the orbit along the undulator has improved the situation to some extent. The ion instability measured with a pico-second streak camera and a one-turn BPM as well as the result of orbit adjustment and chromaticity control will be described in this paper.
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THPCH004 | Space Charge Induced Resonance Trapping in High-intensity Synchrotrons | beam-losses, resonance, space-charge, scattering | 2790 | ||||
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With the recent development of high-intensity circular accelerators, the simultaneous presence of space charge and lattice nonlinearities has gained special attention as possible source of beam loss. In this paper we present our understanding of the role of space charge and synchrotron motion as well as chromaticity for trapping of particles into the islands of nonlinear reonances. We show that the three effects combined can lead to significant beam loss, where each individual effect leads to small or negligible loss. We apply our findings to the SIS100 of the FAIR project, where the main source of field nonlinearities stems from the pulsed super-conducting dipoles, and the beam dynamics challenge is an extended storage at the injection flat-bottom, over almost one second, together with a relatively large space charge tune shift.
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THPCH005 | Considerations for the High-intensity Working Point of the SIS100 | resonance, beam-losses, LEFT, dipole | 2793 | ||||
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In the FAIR project the SIS100 synchrotron is foreseen to provide high-intensity beams of U 28+, including slow extraction to the radioactive beam experimental area, as well as high-intensity p beams for the production of antiprotons. In this paper we discuss the proposal of three different working points, which should serve the different needs: (1) a high intensity working point for U28+; (2) a slow extraction working point (also U28+); (3) a proton operation working point to avoid transition crossing. The challenging beam loss control for all three applications requires a careful account of the effects of space charge, lattice nonlinearities and chromaticity, which will be discussed in detail in this paper. Since tunes are not split by an integer and the injected emittances are different, the Montague stop-band needs to be avoided. Moreover, final bunch compression for the U beam requires a sufficiently small momentum spread, and the risk of transverse resisitive wall instabilities poses further limitations on our choice of working points.
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THPCH006 | Scaling Laws for the Montague Resonance | emittance, resonance, simulation, coupling | 2796 | ||||
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The space-charge-driven Montague resonance is a source of emittance coupling in high-intensity accelerators with un-split tunes. Here we present scaling laws for the stop-band widths, growth rates and crossing behavior of this fourth order resonance. Our results on the coupling can be applied to circular machines as well as to linear accelerators. Based on self-consistent coasting beam simulation we show that for slow crossing of the stop-bands a strong directional dependence exists: in one direction the exchange is smooth and reversible, in the other direction it is discontinuous. We also discuss the combined effect of the Montague resonance and linear coupling by skew quadrupoles.
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THPCH024 | An Efficient Formalism for Simulating the Longitudinal Kick from Coherent Synchrotron Radiation | CSR, space-charge, synchrotron-radiation, simulation | 2829 | ||||
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Coherent Synchrotron Radiation (CSR) can severely limit the performance of planned light sources and storage rings which push the envelope to ever higher bunch densities. In order to better simulate CSR, the formalism of Saldin is extended to work at lower energies and shorter length scales. The formalism is also generalized to cover the case of an arbitrary configuration of multiple bends.
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*E. L. Saldin et al. Nucl. Instrum. Methods Phys. Res., Sect. A 398, 373 (1997). |
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THPCH026 | Parallel 3-D Space Charge Calculations in the Unified Accelerator Library | space-charge, simulation, AGS, instrumentation | 2835 | ||||
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The paper presents the integration of the SIMBAD space charge module in the UAL framework. SIMBAD is a Particle-in-Cell (PIC) code. Its 3-D parallel approach features an optimized load balancing scheme based on a genetic algorithm. The UAL framework enhances the SIMBAD standalone version with the interactive ROOT-based analysis environment and an open catalog of accelerator algorithms. The composite package addresses complex high intensity beam dynamics studies and has been developed as a part of the FAIR SIS 100 project.
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THPCH031 | Impedance and Beam Stability Study at the Australian Synchrotron | impedance, storage-ring, higher-order-mode, resonance | 2844 | ||||
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We present the preliminary results of an impedance study of the Australian Synchrotron storage ring. Beam stability thresholds have been determined and an overall impedance budget set. Broad-band impedance has been evaluted for various components of the vacuum chamber, using both analytical formulae and results from MAFIA simulations. Narrow band resonances have also been investigated, with particular attention paid to higher order modes in the RF cavities and their effect on multi-bunch instabilities.
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THPCH035 | Characterisation of the EU-HOM-damped Normal Conducting 500 MHz Cavity from the Beam Power Spectrum at DELTA | CBM, impedance, single-bunch, storage-ring | 2856 | ||||
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A HOM-damped prototype cavity developed in the framework of an EC collaboration has been installed into the Dortmund synchrotron light source DELTA. This paper reports on beam studies performed at beam energies of 1.5 GeV and 542 MeV in an attempt to get information on coupled bunch instability thresholds. In addition an evaluation of the longitudinal cavity impedance is presented, based on beam power spectra up to 3 GHz for different filling patterns of the storage ring by analysing the RF signal from the HOM-dampers.
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THPCH039 | Beam Studies with Coherent Synchrotron Radiation from Short Bunches in the ANKA Storage Ring | radiation, storage-ring, FIR, synchrotron-radiation | 2868 | ||||
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In the ANKA storage ring it is possible to store bunches with RMS lengths of the order of 1 ps using a dedicated optics with reduced momentum compaction factor. For short bunch operation a beam energy of 1.3 GeV is chosen as a trade-off between low energy longitudinal instabilities and the increase in natural bunch length with energy. At this medium energy (the energy range of the ANKA storage ring is 0.5 to 2.5 GeV) steady state emission of coherent synchrotron radiation is observed by the ANKA-IR beamline below the threshold current defined by the micro-bunching instability. At lower beam energies where the natural bunch length is significantly shorter, bursts of coherent synchrotron radiation are detected in spite of the longitudinal oscillation. The far infrared spectrum is sensitive to the dynamics of the charge distribution generating the radiation. Measurements of the frequency spectrum of the infrared detector signal add information on bunch dynamics. This paper gives an overview of the studies performed at the ANKA storage ring.
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THPCH048 | Transverse Coupled Bunch Instability Driven by 792-MHz Cavity HOM in NewSUBARU Electron Storage Ring | damping, emittance, pick-up, betatron | 2892 | ||||
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The 792-MHz HOM of the RF cavity can drive horizontal coupled bunch instability in the NewSUBARU electron storage ring. This instability is now avoided by tuning the HOM frequency with an additional tuner (HOM tuner). Detailed characteristics of this instability were investigated by changing the HOM frequency, betatron tune, chromaticity and magnitude of the stored current at the energy of 1 GeV. The experiments were performed with 6-bunch equi-space filling to clarify the mode number. Bunch oscillations show saw-tooth patterns when the stored current is not so large. The measured results are compared with an analytical calculation using a rigid bunch model and Sacherer's formalism. The fundamental aspects can be well explained by the calculation, but there exist many problems that cannot be explained by the rigid bunch model.
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THPCH050 | Further Studies on Betatron Sidebands due to Electron Clouds | electron, betatron, feedback, KEKB | 2898 | ||||
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We have observed vertical betatron sidebands in the transverse beam spectra of positron bunches at the KEKB LER which are associated with the presence of electron clouds in single-beam studies*, and which are also associated with a loss of luminosity when the KEKB beams are in collision**. The sidebands may be signals of a fast head-tail instability due to short-range wakes within the electron cloud, providing a diagnostic for exploring the mechanism for transverse beam blow-up due to electron clouds. We report here on further studies on the behavior of the sidebands under varying beam conditions, including varying initial beam size below the beam blow-up threshold, chromaticity, RF voltage and fill pattern.
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*J. W. Flanagan et al. PRL 94, 054801 (2005).**J. W. Flanagan et al. Proc. PAC05, p. 680 (2005). |
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THPCH064 | Comparison of Three CSR Radiation Powers for Particle Bunches and Line Charges | CSR, radiation, synchrotron-radiation, simulation | 2931 | ||||
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We are studying coherent synchrotron radiation (CSR) from arbitrary planar orbits as discussed in another abstract we submitted to EPAC06. It is important to have one-dimensional approximations. Here we report on work constructing and validating such approximations. As part of our work two well known papers by Saldin, Schneidmiller and Yurkov (SSY* are considered which deal with the CSR via a one-dimensional approximation whereby the electron bunch is modelled by a line density. Their one-dimensional approach is important because it is used in various CSR codes and since it serves to some extent as a role model for higher-dimensional models. The present report deals with some general aspects of the work of SSY. In particular, care is taken of the renormalization procedure and of the statistical description in terms of the line density. SSY use a renormalized retarded field whereas the present work uses the radiation field which is defined as half the difference of the retarded and advanced fields. The radiation field came into prominence when Dirac** introduced the Lorentz-Dirac equation.
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*E. L. Saldin, et al. Nucl. Instr. Meth. Phys. Res. A 398, 373 (1997) and 417, 158 (1998).**P.A.M. Dirac, Proc. Roy. Soc. (London) A167, 148 (1938). |
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THPCH067 | Coherent Synchrotron Radiation Studies at the Accelerator Test Facility | injection, radiation, synchrotron-radiation, CSR | 2940 | ||||
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Coherent Synchrotron Radiation (CSR) has been the object of recent experiments and is a topic of great importance for several accelerator currently in their design phase (LCLS, ILC, CIRCE). We present the results of several experimental sessions performed at the Advanced Test Facility - KEK (ATF). An infrared bolometer was used to detect the emitted infrared radiation in the 1-0.05 mm wavelength range as a function of several beam parameters (beam current, RF power, extraction timing, photoinjector laser phase). The beam energy spread was also recorded. We found that the mismatch between injected and equilibrium beam is the source of the coherent signal detected concurrently with the bunch injection.
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THPCH081 | Transverse Impedance of Elliptical Cross-section Tapers | impedance, vacuum, BNL, damping | 2973 | ||||
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We investigate the transverse impedance of elliptical cross-section tapers. Analytical estimates for the dipole and quadrupolar components of the impedance at low frequency are obtained by extending a perturbation approach introduced by Stupakov. The perturbation theory results are compared to EM code GdfidL and are found to be in excellent agreement.
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THPCH088 | A Possibility of Constant Energy Extraction at the KEK ATF2 | extraction, KEK, feedback, kicker | 2994 | ||||
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Beam energy oscillations of the order of 0.02% take place at the KEK ATF. With extractions, the synchrotron oscillation amplitude and phase at the extraction turn randomly fluctuates. The energy jitter causes a position/angle jitter in the Diagnostic section of the Extraction Line. To reduce it, a feed forward energy stabilisation can be used done by extraction of the beam at the turn next to that turn at which the energy passes the equilibrium value. For this, the synchrotron oscillation is measured by a turn-by-turn BPM as a horizontal position oscillation. A fast turn-by-turn processor detects the turn where the oscillation passes zero, and generates an extraction permission signal that triggers the existing ATF Extraction system. Stability improvement by factor of 10 can be obtained even when the extraction is done with uncertainty up to three turns after the trigger.
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THPCH094 | Fully Digitized Synchronizing and Orbit Feed-back Control System in the KEK Induction Synchrotron | induction, controls, acceleration, KEK | 3012 | ||||
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A concept of "Induction Synchrotron", where an extremely long bunch captured by the step barrier-voltages is accelerated with the induction accelerating voltage, is being to be fully demonstrated in the KEK 12GeV-PS for the first time*. Attractive applications of the induction synchrotron are such as higher intensity proton drivers, future high luminosity hadron colliders with superbunch, and arbitral-ion accelerators. Synchronization between the voltage-pulse generation and the beam circulation, accelerating voltage control, and beam-orbit control without beam-rf phase, which is analogous to Delta-R feedback in an RF synchrotron, are indispensable in the induction synchrotron. A fully digitized real-time pulse density and discrete timing control system with 1GHz DSPs has been newly developed. Notable characteristics of the control system, some of which are synchronization at 1MHz revolution frequency with 8ns timing accuracy, are explained in detail. Experimental results of the induction acceleration with the digital orbit controller are also presented in this paper.
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*K. Torikai et al. "Acceleration and Confinement of a Proton Bunch with the Induction Acceleration System in the KEK Proton Synchrotron", submitted to Phys.Rev.ST-AB(2005), KEK-Preprint 2005-80. |
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THPCH098 | FPGA-based Longitudinal Bunch-by-bunch Feedback System for TLS | feedback, kicker, FIR, impedance | 3023 | ||||
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A FPGA Based Longitudinal Bunch-by-Bunch Feedback System for TLS is commissioning recently to suppress strong longitudinal oscillation. The system consists of pickup, Bunch oscillation detector, FPGA based feedback processor borrow form the design of Spring8. Modulator converts the correction signal to the carrier frequency and longitudinal kicker which was re-designed form SLS' and working at 1374 MHz. The feedback processor is based upon latest generation FPGA feedback processor to process bunch signals. The memory capture is up to 250 msec bunch oscillation signal. The software and hardware design are also included for system diagnostic and support various beam physics study. Preliminary commission result will be summaried in this report.
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THPCH109 | Control Applications for SOLEIL Commissioning and Operation | controls, SOLEIL, storage-ring, booster | 3056 | ||||
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Synchrotron SOLEIL, the French third generation light source being commissioned in 2006, is the first facility using TANGO as a full control system. Control applications for operation and Beam Physics Dynamics have being developed using two major tools: the Matlab Middle Layer adapted from ALS and Spear3, and GlobalSCREEN, commercial SCADA software. Both tools are fully interfaced with the TANGO control system. In this paper, a sketch of the software architecture is shown. Then Storage Ring applications developed in house are presented. Finally configuration and database related applications (archiving, snapshot) are briefly described.
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THPCH110 | The New Control System for the Future Low-emittance Light Source PETRA 3 at DESY | controls, DESY, PETRA, linac | 3059 | ||||
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At DESY, the existing high-energy physics booster synchrotron PETRA 2 will be transformed into a 3rd-generation light source (PETRA 3) after the final shutdowm of HERA operation mid 2007. In addition, the technical systems and components of the pre-accelerators LINAC 2 and DESY 2 will be improved. Within the scope of this project, the control system and the front-end electronics will be upgraded. Key elements of the conceptual design are TINE (Threefold Integrated Network Environment) as integrating software bus to provide efficient data communication mechanisms and support services, control room applications based on the thick-client model for optimum visualization and performance and Java as programming language to ensure platform independence, server-side control APIs in various languages to allow choice of the language that is best suited for the control task to be done, a common device interface for generic access to various field buses, and CANopen as interface standard for device electronics to ensure long-term maintenance. The complete conceptual design and the current project status will be presented.
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THPCH111 | Digital Master Oscillator for the ISIS Synchrotron | controls, simulation, lattice, target | 3062 | ||||
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Rutherford Appleton Laboratories in Oxfordshire is home to an 800MeV synchrotron particle accelerator called ISIS. Its main function is to direct a beam of protons into a heavy metal target to produce neutrons for scientists to analyse condensed matter. A second harmonic system is being developed to upgrade the beam current from 200uA to 300uA in order to drive a second target station. This is being achieved by the inclusion of four second harmonic cavities to increase the width of the RF bucket. In the past the six fundamental cavities were driven by an analogue master oscillator but the extra cavities will bring more difficultly in the phasing of the system. This could be more easily and precisely controlled by embedding a Direct Digital Synthesis core into an FPGA chip as the heart of a new digital Master Oscillator. This paper describes the initial research and feasibility of such a system for the setting up, phasing and synchronisation of the ten cavities in the ring. It also describes how more of the controls to the oscillator can be encompassed by digital means.
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THPCH117 | Synchronized Data Monitoring and Acquisition System for J-PARC RCS | monitoring, controls, power-supply, beam-losses | 3077 | ||||
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J-PARC RCS* is a proton synchrotron with an extreme high power of 1MW, and delicate care must be taken to suppress radiation due to beam loss. The RCS injects each beam pulse of 25 Hz into the MLF** and the MR*** in a predefined order. Furthermore, the different beam control parameters are required for the MLF and the MR. Therefore, in order to reduce beam loss, synchronicity of data is indispensable. For this reason, control data monitoring and acquisition must be made separately for each beam pulse, distinguishing the destination in the control system. The data, which require synchronicity monitoring and acquisition, are such as beam position data (BPM**** data). We select mainly these data, and we are developing the synchronized data monitoring and acquisition system based on RM*****, WER******. The status of development and some test results for this system will be presented in this report.
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*Rapid-cycling Synchrotron **Materials and Life Science Facility ***50 GeV Main Ring ****Beam Position Monitor *****Reflective Memory ******Wave Endless Recorder |
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THPCH127 | Development of MATLAB-based Data Logging System at Siam Photon Source | controls, storage-ring, SPS, photon | 3098 | ||||
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New data logging and retrieval systems are currently under development at Siam Photon Source. The systems are written entirely with MATLAB language and utilize two MATLAB toolboxes to handle data communications. The two toolboxes are Open Process Control Toolbox, which is used to carry out communications with Programmable Logic Controllers (PLCs) via Open Process Control Data Access (OPCDA), and Data Acquisition Toolbox, which handles communications with other systems via RS-232 and IEEE-488 interconnections. The interface with the database is handled by the MATLAB Database Toolbox. These MATLAB-based logging and retrieval systems enable accelerator physicists to easily import the logged data to accelerator modeling tools for studies of the accelerator optics. Beamline researchers and users can also write their own retrieval programs to access only the data they need. In this paper we describe the concept, the current status of the systems, and the planned improvements to be carried out in the future.
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THPCH132 | EPU Assembly Based on Sub-cassettes Magnetic Characterization | undulator, electron, polarization, radiation | 3107 | ||||
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A procedure to speed up the magnetic field correction of an EPU type undulator is proposed and its results are shown. Such procedure consists in segmenting each one of the four magnetic blocks linear arrays (cassettes) in seven sub-cassettes and making their individual magnetic and mechanical characterization. One theoretical perfect sub-cassette, which is composed of four segments per period in Halbach configuration, is taken as the standard field profile. The peak fields and the fields integrated in each semi-period of one sub-cassette are chosen to be the optimization parameters. The magnetic blocks are displaced (virtual shims) to minimize the difference of the optimization parameters between the sub-cassette magnetic measurement and the standard profile. The sub-cassette magnetic measurements are performed with Hall probes, using the same bench employed in insertion devices characterization.
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THPCH133 | Conceptual Design of an EPU for VUV Radiation Production at LNLS | undulator, controls, polarization, vacuum | 3110 | ||||
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We describe the magnetic and mechanical design of an elliptically polarizing undulator (EPU) currently under construction at the (Brazilian Synchrotron Light Source - LNLS). The device is designed to cover the photon flux in the range from 100eV to 1000eV (124Å a 12.4 Å), allowing linear, elliptical and circular polarizations. With this device it is possible to reach absorption edges of several elements such as Si, S, Br, C, N, O, Fe, F, Cl and to measure magnetic dichroism. The EPU's magnetic design is conventional, and field corrections are done by means of virtual shims, with horizontal and vertical displacements. Each one of the four magnetic blocks linear arrays (cassettes) is segmented in seven sub-cassettes. The separate magnetic measurement of each sub-cassette allows corrections of the magnetic field profile to be made before final assembly and makes the verification of mechanical tolerances easier and faster, decreasing the expected time that will be spent in the magnetic tuning of the device. The mechanical structure is composed of a C-Frame, gap and phase actuators. The gaps actuators and phase actuators use absolute encoders and bias with springs to eliminate backlash.
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THPCH134 | Development of Insertion Device Magnetic Characterization Systems at LNLS | insertion, insertion-device, wiggler, controls | 3113 | ||||
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This paper describes a set of magnetic measurement systems employed in the development of insertion devices at LNLS (Brazilian Synchrotron Light Source). They are: rotating coil (which can also operate as a flip-coil), spatial field mapping using Hall probes and parallel coils (Helmholtz configuration) for magnetic blocks characterization. Although such techniques are well established, strict specifications imposed by the beam dynamics on the magnetic field quality, led to a detailed analysis of their sources of error and their minimization. All three systems have already been tested and showed excellent accuracy and repeatability when compared to typical values found in the literature.
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THPCH168 | RF Distribution System of the Diamond Master Oscillator | DIAMOND, linac, storage-ring, booster | 3188 | ||||
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A modular RF distribution system has been designed and built at Diamond Light Source to distribute the master oscillator (MO) signal. The system will deliver a low noise, phase stable 500 MHz signal to multiple points of use around the synchrotron facility. Providing phase stability and preserving noise performance over the distances required (up to 300m) have been the main design challenges. A modular approach provides future flexibility, and this paper describes each component, outlining design choices, components used, construction details and test results.
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THPCH170 | Reduction of Dark Current in SPring-8 Linac | electron, linac, gun, simulation | 3194 | ||||
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In the SPring-8 linac, removal of dark currents generated from an injector part has been studied to enhance the bunch purity of stored beam in the SPring-8 storage ring. We already succeeded in reduction of the dark currents from a thermionic electron gun by a beam deflector of parallel plate electrodes. However, dark currents are also generated in accelerating structures due to the high electric fields. We have been studying removal of the dark currents generated from the first accelerating structure by solenoid coils covering it.
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THPCH172 | Present Status of Beam Collimation System of J-PARC RCS | proton, radiation, vacuum, target | 3200 | ||||
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The precedence manufacture of the two beam collimator was carried out. In these two sets, we tested the heat transfer capacity of cooling fins and remote clamp handling system. The vertical collimator was able to keep temperature under 120 degrees C by the design heat 400W, but in case of the horizontal collimator, it went over 200 degrees C by the design heat 700W. The design was changed towards adding an air duct. About remote clamp handling system, it checked that it could attach by the He leak below 5.*10-10Pa m3/sec as a result of the helium leak examination.
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THPCH186 | Magnetic Field Measurement and Fine-tuning of Kickers | kicker, injection, storage-ring, synchrotron-radiation | 3236 | ||||
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We have demonstrated an algorithm which promisingly can tune the pulse shape of current and magnetic field of kicker systems in-situ. This algorithm includes gap shimming of the ferrite magnets to adjust the pulse width of the excitation current and changing the resistance of the secondary coils to modify the pulse curvatures of each kicker. With the empirical formula derived from the systematic measurement on the magnetic field and the pulse current in laboratory, we can reduce the pulse-shape difference among the kicker magnets in the injection section of the storage ring, with no need to do anything on the pulsers and high voltage power suppliers. This approach can efficiently increase the injection efficiency which is demanding in the top-up injection mode adopted by many new facilities of synchrotron radiation.
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THPLS001 | The Strict Solution of a Radiation Problem in Toroidal Cavity | radiation, synchrotron-radiation, plasma, electromagnetic-fields | 3260 | ||||
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The radiation of charged particles bunch which is moving along the axes of toroidal cavity cross section is considered. The toroidal cavity has a finite value of the quality factor and is filled with special symmetry inhomogeneous dielectric medium. The problem's solution is based on the complete set of the toroidal cavity's own modes being defined strictly for the mentioned dielectric medium the cavity is filled with. The charged particles bunch exists in the cavity during a finite time period and the charged bunch's arising and vanishing effects are examined and are taken into account as well. The toroidal cavity is considered as a convenient model to investigate the electromagnetic properties of the tokamak system, using the defined modes.
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THPLS002 | X-ray and Optical Diagnostic Beamlines at the Australian Synchrotron Storage Ring | diagnostics, storage-ring, controls, electron | 3263 | ||||
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Two diagnostic beamlines have been designed and constructed for the Australian Synchrotron Storage Ring. One diagnostic beamline is a simple x-ray pinhole camera system, with a BESSY II style pinhole array, designed to measure the beam divergence, size and stability. The second diagnostic beamline uses an optical chicane to extract the visible light from the photon beam and transports it to various instruments. The end-station of the optical diagnostic beamline is equipped with a streak camera, a fast ICCD camera, a CCD camera and a fill pattern monitor. The beamline design and some commissioning measurements are presented.
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THPLS003 | When Less is More - Construction of the Australian Synchrotron | storage-ring, injection, undulator, linac | 3266 | ||||
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The Australian Synchrotron is a 3 GeV facility under construction next to Monash University in Melbourne. The project was launched in January 2003 and is scheduled for completion in March 2007. The funding of Aus$206M (about 125 MEuros) covers all costs associated with the site, building, accelerators and the first nine beamlines. The building contract was placed in July 2003 and completed in February 2005. Installation of the accelerators began in April 2005 and should be complete by May 2006. Commissioning of the injection system began in October 2005, and storage ring commissioning will begin mid-2006, with beamline commissioning beginning January 2007 and facility handover in March 2007. The project is being delivered with a staff of less than 50, which has meant that much of the detailed design work and project management for major systems (e.g., the injection system, RF system, support girders, vacuum vessels and front ends) has been performed by commercial suppliers under turn-key contracts. The presentation will discuss the main technical challenges, and results will be presented of the commissioning of the linac, booster and storage ring.
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THPLS005 | Commissioning Results from the Injection System for the Australian Synchrotron Project | injection, booster, quadrupole, emittance | 3272 | ||||
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Danfysik has built a full-energy turnkey injection system for the Australian Synchrotron. The system consists of a 100 MeV LINAC, a low-energy transfer beamline, a full-energy booster and a high energy transfer beamline. The booster synchrotron will deliver a 3-GeV beam with an emittance of 33 nm. The lattice is designed to have many cells with combined-function magnets (dipole, quadrupole and sextupole fields) in order to reach this very small emittance. The current in single- and multi-bunch mode will be in excess of 0.5 and 5 mA, respectively. The repetition frequency will be 1 Hz. At the time of writing this abstract, the LINAC beam has been injected into the low-energy transfer beamline. The project is on schedule for delivery in April 2006. Results from the commissioning of the system will be presented together with its performance.
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THPLS014 | Status of the Metrology Light Source | microtron, storage-ring, injection, electron | 3299 | ||||
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For more than 25 years, the Physikalisch-Technische-Bundesanstalt (PTB) uses synchrotron radiation at the storage rings BESSY I and II for photon metrology in the spectral range of UV to x-rays. Since decommissioning of BESSY I (1999), there is a gap in the spectral range of UV and EUV wavelength due to the higher electron energy of BESSY II. Thus, in 2003, the Metrology Light Source (MLS), a low energy electron storage ring, was approved, as central instrument in the future Willy Wien Laboratory (WWL). Design, construction and operation of the MLS are realized by BESSY, based on the PTB requirements for a permanent accessible radiometry source, optimized for the spectral range between UV up to VUV. The MLS is tuneable in energy between 200 MeV and 600 MeV, designed for currents between 1pA up to 200mA. Civil construction of WWL in the close vicinity to BESSY is nearing completion. The first MLS components will be installed in spring 2006, commissioning of the 100MeV Microtron is scheduled for summer 2006, while commissioning of the storage ring will start in spring 2007. Regular user operation will begin in January 2008. A status and an overview on the construction of the MLS are
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THPLS017 | Orbit Stability in the 'Low Alpha' Optics of the BESSY Light Source | storage-ring, insertion, insertion-device, optics | 3308 | ||||
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Running the light source during dedicated shifts in the so-called 'low alpha' mode, BESSY serves two major user groups: THz experiments take advantage of intense, coherent synchrotron radiation (CSR) generated by the short bunches. Time resolved experiments appreciate the very short, high intensity VUV and x-ray pulses in the ps range that help, e.g., prepare the high resolution, low intensity fs-slicing experiments. In the 'low alpha' mode, the sensitivity of the storage ring with respect to energy and horizontal orbit is increased by orders of magnitude while the user experiments require the same beam stability as in 'normal' mode. In this paper an overview of the operational conditions of this specific user mode, the stabilization measures taken, observations and available diagnostic results as well as the achievements and shortcomings of the adapted slow orbit feedback are given.
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THPLS019 | The Metrology Light Source: an Electron Storage Ring Dedicated to Metrology | electron, radiation, storage-ring, photon | 3314 | ||||
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PTB, the German National Metrology Institute, in close cooperation with BESSY, is currently setting up a low-energy electron storage ring (200 MeV up to 600 MeV electron energy), the Metrology Light Source MLS, which will be dedicated to metrology and technology development in the UV and EUV spectral range which synchrotron radiation. The MLS has been designed by BESSY according to PTB specifications. User operation is scheduled to begin in 2008. Currently, the building, housing the storage ring, is nearly completed, and all major parts of the storage ring and the injection system have been ordered or have already been delivered. The MLS will be equipped with all the instrumentation necessary to measure the storage ring parameters needed for the calculation of the spectral photon flux according to the Schwinger theory with low uncertainty, enabling PTB to operate the MLS as a primary source standard. Moreover, calculations show, that the MLS is ideally suited for the production of coherent synchrotron radiation in the far IR and THz region. We give a status update on the construction, the instrumentation for the measurement of the storage ring parameters and calculations for a low-
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THPLS027 | Vibration Measurement at Diamond and the Storage Ring Response | DIAMOND, storage-ring, ground-motion, site | 3338 | ||||
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Controlling and minimising the sources and transmission of vibration in Synchrotron Light Sources is an important factor in achieving the stability needed to generate the very brightest beams. This paper describes the equipment that has been used at Diamond to measure vibration and reports the results of measurements taken on the accelerator floor and on the girder structures carrying the Storage Ring. A description is given of the intensively piled foundations and a comparison is made between the measured response and the modelled response. The contribution to vibration from water and ventilation services is also discussed.
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THPLS041 | Observation of Intense Terahertz Synchrotron Radiation produced by Laser Bunch Slicing at UVSOR-II | laser, electron, radiation, CSR | 3377 | ||||
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We have performed electron bunch slicing experiments using a femto-second high power pulse laser in the UVSOR-II electron storage ring. As the pulse laser system we have used a Ti:Sa laser whose wavelength is 800 nm, typical pulse duration is 100 fs, pulse repetition is 1 kHz and typical average power is 2W. The laser is operated in mode-locked condition and synchronized with the electron beam revolution. The laser pulse is injected into an undulator section and it goes along with the electron bunch. By adjusting the radiation wavelength of the undulator to the laser wavelength, the electron beam energy can be partially modulated in the electron bunch. We have observed THz synchrotron radiation (SR) light from a bending magnet that is downstream of the interaction region. The SR light contains extremely intense THz pulse radiation that is synchronized with the laser injection. The extremely high intensity strongly suggests that the THz pulses are coherent synchrotron radiation from the electron bunch with a hole because of the laser-beam interaction.
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THPLS042 | Observation of THz Synchrotron Radiation Burst in UVSOR-II Electron Storage Ring | radiation, electron, synchrotron-radiation, CSR | 3380 | ||||
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Very intense THz synchrotron radiation bursts have been observed in single-bunch operation in the UVSOR-II electron storage ring*. The observation was performed in an infrared beam line in UVSOR-II by using a liquid-He-cooled In-Sb hot-electron bolometer that has a good response time of several microseconds. Thanks both to the beam line and the detector, it is clearly observed that the intense bursts have typical macroscopic and microscopic temporal structure. Macroscopically, it is clearly observed that the bursts tend to be generated with quasi-periodic structure in which the period tends to depend on the beam intensity. From a microscopic point of view, each burst has also quasi-periodic structure in itself, and the period almost corresponds to the half value of the inverse of the synchrotron oscillation frequency. The peak intensity of the bursts was about 10000 times larger than that of ordinary synchrotron radiation in the same wavelength region. The extremely high intensity strongly suggests that the bursts are coherent synchrotron radiation, although the radiation wavelength was much shorter than the electron bunch length.
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*Y. Takashima et al., Jpn. J. Appl. Phys. 44, No.35 (2005) L1131. |
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THPLS052 | The Vacuum System for the Spanish Synchrotron Light Source (ALBA) | vacuum, storage-ring, dipole, photon | 3398 | ||||
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ALBA will be a 3GeV, third generation synchrotron light facility to be built near Barcelona (Spain). The design phase of ALBA is almost completed and the main components have been ordered, which includes the vacuum chambers for the storage ring. Commissioning of the storage ring is foreseen to start at the end of 2008. The circumference of the storage ring of ALBA is 268.8 m, and it will be divided into 16 vacuum sections by ultra high vacuum (UHV) gate valves. The vacuum chamber will be made of stainless steel with an internal vertical aperture of 28 mm and 72 mm width. The vacuum chamber will be connected to an antechamber with a slot of 10 mm height and 20 mm width. The antechamber will have the discrete absorbers, which will absorb the unwanted synchrotron radiation. The pumping will be by sputter ion pumps (SIP) and NEG pumps, with an overall pumping speed from SIP of 57400 l/s. This will maintain an average dynamic pressure of around 1.0·10-9 mbar to achieve a beam lifetime > 15 hours at the designed current. No in-situ bakeout is foreseen, as the vacuum section will be conditioned ex-situ and installed under vacuum to the storage ring.
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THPLS053 | Status of the ALBA Project | storage-ring, booster, vacuum, insertion | 3401 | ||||
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ALBA is a 3 GeV light source being built near Barcelona, Spain. ALBA is optimized for high flux density and a large number of available straight sections for insertion devices (3x8 m, 12x4.2 m) in a relatively small circumference of 268.8 m. The light source should be operational in 2010, including the operation of seven beamlines, including six insertion devices. The design of the lattice and of the major components of the accelerator complex (linac and booster, magnets, RF system, vacuum system) is finish and the procurement procedure has started for the large majority of them. The construction of the building will start in the first half of 2006. This report offers an overview of the status of the project, with special emphasis in the new developments.
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THPLS056 | Synchrotron Radiation Monitors at ALBA | radiation, synchrotron-radiation, booster, vacuum | 3410 | ||||
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ALBA is a 3 GeV, low emittance third generation synchrotron light source that is in the construction phase in Cerdanyola, Spain. Synchrotron Radiation Monitors (SRM) are one of the most useful, non-destructive tools to easily obtain information of three important parameters for a synchrotron user: beam position, beam dimensions and beam stability. These monitors diagnose beam performance using the radiation produced when the beam traverses a bending magnet. An extensive usage of SRM, based on the visible part of the spectrum, is planned in the ALBA synchrotron: Linac, Booster, Transfer Lines and the Storage Ring. The latter will be equipped as well with an SRM based on the x-ray part of the spectrum, using the PinHole technique in order to accurately measure the low beam size and emittance. This paper describes the different SRM designs for the ALBA light source.
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THPLS065 | Optimization for Taiwan Photon Source Electron Beam Position Monitors through Numerical Simulation | simulation, electron, photon, synchrotron-radiation | 3436 | ||||
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One of the key steps toward successfully building the newly proposed 3rd generation synchrotron radiation research facility, Taiwan Photon Source (TPS), is to optimize the design of the high resolution electron beam position monitors through numerical simulation. With more advanced electromagnetic simulation tool like MAFIA tailored specifically for particle accelerator, the design for the high resolution electron beam position monitors can be tested in such environment before actually fabricated and physically tested. The design goal of our high resolution electron beam position monitors is to achieve 0.1 micron resolution if allowed by engineering limitations. The design consideration to achieve this 0.1 micron resolution goal will also be discussed. The first design has been carried out and the correlated simulations were also carried out with MAFIA. The results are presented and discussed here. Sensitivity as high as 200 has been achieved at 500 MHz. Further study will also be described.
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THPLS068 | Design of Taiwan Future Synchrotron Light Source | emittance, dynamic-aperture, coupling, lattice | 3445 | ||||
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We report updated design works for a new 3-3.3 GeV synchrotron light source with a high performance and low emittance storage ring, called Taiwan Photon Source (TPS). With its natural horizontal emittance less than 2 nm-rad and low emittance coupling, TPS will be able to provide an extremely bright photon beam to the demanding users, especially the x-ray community. The lattice type of the TPS is a 24-cell DBA structure and the circumference is 518.4 m. We present the lattice design, the accelerator physics issues and its performances.
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THPLS073 | Effect of Nonlinear Synchrotron Motion on TPS Energy Acceptance | lattice, vacuum, emittance, sextupole | 3451 | ||||
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For design of new generation synchrotron light source the first order momentum compaction factor is usually small. The contribution of second order momentum compaction factor can't be neglected. The longitudinal phase space changes significantly due to the nonlinear effect. This will affect the energy acceptance of the particles and reduce the Touschek beam life time. In this paper we analyze the effect of the nonlinear synchrotron motion of TPS lattice design*. The reduction of energy acceptance is estimated. The contribution to second order momentum compaction factor is discussed. Efforts to minimize this nonlinear effect will also be addressed.
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*C. C. Kuo et al., "Design of Taiwan Future Synchrotron Light Source", these proceedings. |
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THPLS087 | A Control Theory Approach for Dynamic Aperture | dynamic-aperture, sextupole, lattice, controls | 3478 | ||||
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The dynamic aperture problem dates back to the design of the first synchrotrons. Over time, both analytical and numerical methods have been pursued. In the former case mainly by applying techniques developed for celestial mechanics to rather simplified equations of motion. Over the last decade, analysis of the Poincare map has become the method of choice. In particular, application of symplectic integrators, truncated power series algebra, and Lie series techniques has led to a complete set of tools for self-consistent numerical simulations and analytic treatment of realistic models. Nevertheless, a control theory for the general nonlinear case remains elusive. We summarize how to apply this framework to the design of modern synchrotron light sources. Moreover, we also outline how a control theory can be formulated based on the Lie generators for the nonlinear terms.
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THPLS111 | Beam Loading Measurement and its Application to the Harmonic RF Control of the APS PAR | beam-loading, injection, controls, photon | 3538 | ||||
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The particle accumulator ring (PAR) has dual rf systems: a CW mode fundamental rf system (RF1) operating at 9.77 MHz that accumulates multiple linac pulses into a 0.8-ns bunch, and a 12th harmonic rf (RF12) that compresses the bunch length further to 0.34 ns for injection into the booster. The RF12 capture process is critical for optimal performance of the PAR. We investigated the effects of beam loading during the RF12 capture and bunch length compression process with both spectrum analysis and streak camera imaging. Based on these observations, a new timing scheme for the RF12 tuner and power control was implemented, which has substantially improved the performance of the PAR. We report our observation, the new timing scheme, and beam parameters after optimization.
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THPLS122 | Investigations of the Thermal Beam Load of a Superconducting In-vacuum Undulator | undulator, vacuum, radiation, synchrotron-radiation | 3568 | ||||
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Both the resistive wall effect and the synchrotron radiation~\cite{wallen, casalbuoni, chou} can warm up the cold bore of a superconductive in-vacuum undulator. For the in ANKA installed superconducting undulator measurements showed that the dominant heat load contribution comes from the synchrotron radiation generated in the upstream bending magnet: 1 W per 100 mA stored current at a beam energy of 2.5 GeV and an undulator gap of 8 mm.
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THPLS123 | A Year's Experience with a Superconducting Undulator in the Storage Ring ANKA | undulator, emittance, optics, synchrotron-radiation | 3571 | ||||
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In ANKA the worldwide first superconducting undulator demonstrator designed for a storage ring was operated during the last year. The undulator has 100 periods and a period length of 14 mm. During the first year the heat transfer from the beam to the cold bore was investigated and the spectra and the electrical tunability together with a monochromator was measured. The results are so encouraging that plans exist to equip ANKA with two more undulators, one with the opportunity to double electrically the period length and one with electrically variable polarization direction.
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FRYAPA01 | Developments in Proton and Light-ion Therapy | ion, proton, target, linac | 3631 | ||||
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The talk will provide an overview of recent developments in hadrontherapy. It will give a background on cancer therapy with protons and ions, discussing the relative merits of protons and ions versus conventional radiotherapy. It will include status and plans for the development of hadrontherapy facilities, in particular in Europe. It will also describe the status of the Italian hadrontherapy project (CNAO).
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Transparencies
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