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TU-10 | RF Sytem for Heavy Ion Cyclotrons at RIKEN RIBF | cyclotron, acceleration, ion, pick-up | 69 |
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At RIKEN RIB-factory (RIBF) an accelerator complex as an energy booster which consists of superconducting ring cyclotron (SRC), intermediate-stage ring cyclotron (IRC) and fixed-frequency ring cyclotron (FRC) provides very heavy ion beams like uranium with an energy of 345 MeV/u. The total beam power obtained up to now at the SRC is as high as 3 kW in the case of 48Ca with an intensity of 170 pnA. Recently we have succeeded in achieving stable and reliable operation of rf system for new cyclotrons. In this paper the present performance of the rf system and a recent development is reported. |
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TU-11 | A Novel Design of a Cyclotron Based Accelerator System for Multi-Ion Therapy | cyclotron, ion, extraction, injection | 74 |
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A cyclotron based system for hadron therapy is developed, which allows a phased installation: start with protons and Helium ions and add Carbon ions later. The concept is based on an accelerator system of two coupled cyclotrons. The first cyclotron provides protons or He ions that can be used for the full spectrum of treatments and “low energy” C-ions, with a range of 12.7 cm in water for a subset of tumours and radiobiological experiments. For treatments at all tumor sites with C-ions, the C-ions can be boosted subsequently up to 450 MeV/nucl in a separate sector cyclotron, consisting of six sector magnets with superconducting coils and three RF cavities. First studies of the separate sector cyclotron indicate a relatively robust design with straight forward beam dynamics. This system is smaller than corresponding synchrotrons and possesses the typical advantages for therapy applications of a cyclotron. Present efforts to optimize the design of the superconducting sector magnets indicate that the introduction of a radial gradient in the sector would have many advantages. |
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TU-12 | Design Study of Medical Cyclotron SCENT300 | cyclotron, ion, proton, extraction | 79 |
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The study of the Superconducting Cyclotron named SCENT300 was carried out by the accelerator R&D team of Laboratori Nazionali del Sud (LNS-INFN) of Catania in collaboration with the University of Catania and supported by IBA (Belgium). Combining the compactness of a superconducting cyclotron, with the advantage of this kind of machine as its continuous beam and its very good current control, the accelerator R&D group of LNS, by its ten-year of experience with this kind of machine, has developed a concept for a multiparticle therapy cyclotron which is described in the following report. |
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TH-02 | Commissioning of the ATLAS Upgrade Cryomodule | cryomodule, solenoid, vacuum, ion | 151 |
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Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357. The ongoing energy upgrade of the heavy-ion linac ATLAS at ANL includes a new cryomodule containing seven 109MHz β=0.15 quarter-wave superconducting cavities to provide an additional 15 MV voltage. Several new features have been incorporated into both the cavity and cryomodule design. For example, the cryomodule separates the cavity vacuum space from the insulating vacuum, a first for TEM cavities. The cavities are designed in order to cancel the beam steering effect due to the RF field. Clean techniques have been applied to achieve low-particulate rf surfaces and are essential for reliable long-term high-gradient operation. The sealed clean subassembly consisting of cavities, beam spools, beam valves, couplers, vacuum manifold, and support frame has been attached to the top plate of the cryomodule outside the clean room. Initial commissioning results are presented. The module was designed and built as a prototype for the Facility for Rare Isotope Beams (FRIB) driver linac, however, a similar design can be effectively used in the front-end of SC proton linacs based on TEM-class SC cavities. |
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TH-03 | Frequency Tuning and RF Systems for the ATLAS Energy Upgrade SC Cavities | cryomodule, vacuum, coupling, niobium | 156 |
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Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357. A new cryomodule with seven low-beta superconducting radio frequency (SRF) quarter wave niobium cavities has been designed and constructed as an energy upgrade project for the ATLAS accelerator at Argonne National Laboratory. The technology developed for this project is the basis for the next generation superconducting heavy ion accelerators. This paper will discuss the methods employed to tune the cavities eigenfrequency to match the accelerator master oscillator frequency and the development of the RF systems used to both drive the cavity and keep the cavity phase locked during operation. |
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TH-05 | HIE-ISOLDE LINAC: Status of the R&D Activities | linac, cryomodule, solenoid, vacuum | 165 |
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For the post-accelerator of radioactive ion beams at CERN a major upgrade is planned to take place in the next 4-5 years. The upgrade consists in boosting the energy of the machine from 3MeV/u up to 10 MeV/u with beams of mass-to-charge ratio 2.5<A/q<4.5 and in replacing part of the existing normal conducting linac. The new accelerator is based on two gap independently phased 101.28 MHz Nb sputtered superconducting Quarter Wave Resonators (QWRs). Two cavity geometries, “low” and “high” β, have been selected for covering the whole energy range. A R&D program has started in 2008 looking at the different aspects of the machine, in particular beam dynamics studies, high β cavity development and cryomodule design. A status report of the different activities is given here. |
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TH-07 | Operational Experience of the Superconducting LINAC Booster at Mumbai | linac, controls, cryogenics, acceleration | 174 |
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The superconducting LINAC booster, indigenously developed to boost the energy of the heavy ion beams from the 14 MV Pelletron accelerator at TIFR, Mumbai, has been fully operational since July 2007. The LINAC consists of seven modular cryostats, each housing four lead plated quarter wave resonators, designed for an optimum velocity β0=0.1 at an operating frequency of 150 MHz. In order to maintain a stable phase and amplitude of the electric field in the cavity, the RF controller cards based on a self-excited loop (SEL) with phase and amplitude feedback have been developed indigenously. The cryogenic system for the LINAC has been designed for a typical power dissipation of 6 W in each resonator. Initial beam trials have yielded average energy gain of 0.4 MV/q per cavity corresponding to 80% of the design value. Operational experience of the LINAC, namely, empirically devised procedures for the acceleration of different beams and RF settings, and associated developments are presented. |
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FR-03 | Improved on line performance of the installed ALPI Nb sputtered QWRs | superconductivity, cathode, linac, niobium | 203 |
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The average accelerating field of the ALPI 160 MHz sputtered QWRs has been improving with time up to reach, after the last conditioning cycle, the average accelerating field of 4.8 MV/m @ 7 W. Such value can be effectively sustained in operation due to the intrinsic mechanical stability of the sputtered cavity whose frequency is practically not influenced by fluctuations in the bath He pressure. The present average cavity performance approaches the maximum average accelerating field obtainable in the presently installed cavities, most of which were produced by replacement of Pb with Nb in the previously installed substrates. A higher average value can be obtained in ALPI replacing the less performing units; it is instead necessary to sputter on appropriately built substrates to produce QWRs which can reliably exceed 6 MV/m @7W. The cavity Q-curves, which were recently measured in ALPI, show a wide range of Q0 and Q-drop, mainly associated with the substrate characteristics, but in some cases also influenced, as discussed in the paper, by cryostat assembling procedures and by cavity production and conditioning. |
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FR-04 | Operational Experience in PIAVE-ALPI Complex | rfq, ion, SRF, ECR | 208 |
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PIAVE-ALPI is the INFN-LNL superconducting heavy ion linac, composed by an SRFQ (superconducting RFQ) section and three QWR sections for a total of 80 cavities installed and an equivalent voltage exceeding 70 MV. In the last years the SRFQ and the bulk niobium QWR came into routine operation, the medium energy QWR section was upgraded with a new Nb sputtered coating, ECR source was firstly improved by using water cooled plasma chamber and then replaced with a new one. The operation of the accelerator complex allowed acquiring a strong experience on many operational issues related to ECRIS, superconducting cavities and cryogenics, beam control and manipulation (with the new and higher accelerating gradient). The paper reports about operational experience, the present limitations and the future perspectives of the facility in view of the experimental campaign with the EU detector AGATA and of the use of PIAVE ALPI as RIB post-accelerator for SPES radioactive ion beam facility. |
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A-01 | Reference Signal Generation with Direct Digital Synthesis for FAIR | antiproton, radio-frequency, synchrotron, ion | 218 |
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In this paper, a method for the generation of RF reference signals for synchrotrons and storage rings will be presented. With these reference signals, the RF cavities in the Facility for Antiproton and Ion Research (FAIR) shall be synchronised. Digital frequency generators that work according to the DDS (direct digital synthesis) principle will be used as reference generators. Via an optical network with star topology, these reference generators will be fed with two clock signals that show a certain correlation of frequency and phase. Due to delay measurements, their phases at different end points of the optical network are known. From these clock signals, reference signals with specific frequencies can be derived. The phases of these reference signals can be fine-tuned against the phases of the clock signals, allowing the phases of different reference signals to be synchronised. With the commercially available DDS generators used in the prototype, phase steps of 0.022° are possible. At a reference signal frequency of 50 MHz, this corresponds to 1.22 ps. The presentation describes the functionality of this method for reference signal generation and shows under which conditions the step size of the phase adjustment can be improved further. |
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C-01 | Conceptual Design of a Radio Frequency Quadrupole for the Heavy-Ion Medical Facility | rfq, simulation, emittance, ion | 245 |
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Design of conventional 4-vane/rod type of RFQ (Radio Frequency Quadrupole) for the heavy ion medical facility has been studied. The RFQ is capable of accelerating C4+ ions from an initial energy of 10 keV/u to 300 keV/u. In this work, all the design parameters have been optimized to achieve stable structure and compactness. The 3D electromagnetic field distribution and RF analysis were obtained by CST Microwave Studio and the field was used in TOUTATIS for beam simulation. This paper shows the determined physical and mechanical design parameters of RFQ. |
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C-06 | Fabrication of Superconducting Niobium Resonators at IUAC | niobium, vacuum, linac, cryomodule | 266 |
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The facility for constructing superconducting niobium resonators indigenously was commissioned at the Inter- University Accelerator Centre in 2002. It was primarily setup to fabricate niobium quarter wave resonators for the superconducting booster linac. Starting with a single quarter wave resonator in the first phase, two completely indigenous resonators were successfully built, tested and installed in the cryomodules. Subsequently production of fifteen more resonators for the second and third modules began. Several existing resonators have been successfully reworked and restored from a variety of problems. In addition to building resonators for the in-house programs, a project to build two single spoke resonators for Project- X at Fermi Lab, USA has also been taken up. A Tesla-type single cell cavity is also being built in collaboration with RRCAT, Indore. This paper presents details of the fabrication, test results and future plans. |
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C-08 | Wide Bandwidth, Low Cost System for Cavity Measurements | controls, pick-up, superconducting-cavity, superconductivity | 274 |
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Recently we developed a novel measurement apparatus that simplify the tests of superconducting cavities. A few commercial electronic boards, mounted in a devoted chassis and controlled by a PC, operate most of the functions usually carried out by standard RF instrumentation. The set up allows the measurements of resonators in the 80-700 MHz frequency range and we used it to characterize resonators both in the ALPI vault and in off-line tests. Upgraded control program carries out all the typical procedures, related to the cavity measurements in classical VCO-PLL system. It allows to adjust and to measure the RF forward power, to find and update the cavity resonant frequency, to calibrate the pick-up signal, to monitor the transmitted power, to adjust the coupler position. The implemented automatic procedures permit to measure the cavity decay time, to trace the Q-curve, to perform CW and pulse RF conditioning, to calibrate cables and measurement instruments. The same software applies to the other two measurement systems routinely used at Legnaro to test resonators up to 6 GHz frequency. |
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C-09 | Design of the MEBT Rebunchers for the SPIRAL 2 Driver | controls, simulation, radio-frequency, resonance | 278 |
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The Spiral 2 project uses normal conducting rebunchers to accelerate high intensity beams of protons, deuterons and heavier ions. All cavities work at 88 MHz, the beta is 0.04 and 3 rebunchers are located in the MEBT line, which accepts ions with A/q up to 6. The paper describes the RF design and the technological solutions proposed for an original 3-gap cavity, characterised by very large beam aperture (60 mm) and providing up to 120 kV of effective voltage. |