Paper | Title | Other Keywords | Page |
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MO101 | ISAC-II Operation and Future Plans | ISAC, ion, target, TRIUMF | 1 |
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The ISAC-II superconducting heavy ion linac now accelerates radioactive ion beams with the highest gradient of any operating SC ion facility in the world and provides a 20 MV boost to the ISAC accelerated beams. The addition of a further 20 MV of SC linac, with cavities made in Canada, will be installed by the end of 2009. The ISAC-III project scheduled to begin in 2010 will see the installation of an additional driver beam of 50 MeV electrons to produce RIBs by photofission, an expanded target area, and new front-end ion accelerators to expand the capability to three simultaneous radioactive beams for experiments. |
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MO102 | The European XFEL SC Linac Project | FEL, undulator, electron, radiation | 6 |
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The European XFEL project is entering the construction phase, based on the very successful experience of the TESLA linac technology and the SASE FEL concept, now serving the FLASH user facility at DESY. The EU-XFEL will be realized by a widespread international collaboration and it is also relevant for the ILC planning. A description of the overall layout of the facility, of the technical developments and industrialization efforts for the accelerator components, and of the international collaboration will be given. |
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MO103 | SNS Superconducting Linac Operational Experience and Upgrade Path | cavity, cryomodule, SRF, HOM | 11 |
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Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy |
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MO201 | Progress in the Beam Commissioning of J-PARC Linac and its Upgrade Path | rfq, cavity, neutron, target | 16 |
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The beam commissioning of J-PARC linac has been started since November 2006, and the initial commissioning has been completed in September 2007. Since then, the linac beam has been supplied to the succeeding RCS (Rapid Cycling Synchrotron) for its commissioning with occasional linac beam studies for finer tuning. The emphasis of the linac tuning has been shifted to the characterization and stabilization of the beam parameters, and better beam availability has gradually been required for the linac operation. In this paper, we present the current linac performance and operational experience obtained so far after a brief review of the commissioning history. Remaining commissioning tasks and the future upgrade plan to increase the beam power are also discussed. |
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MO202 | Status of a High Current Linear Accelerator at CSNS | rfq, DTL, ion, ion-source | 21 |
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China Spallation Neutron Source (CSNS) consist of an H- linac as an injector of a rapid cycling synchrotron of 1.6 GeV. The 324 MHz rf linac is designed with beam energy of 81 MeV and a peak current of 30 mA. The linac design and R&D are in progress. A test stand of a Penning ion source is under construction. RFQ technology has been developed in ADS study, with beam energy of 3.5 MeV, a peak current of 47 mA at 7% duty factor and a beam transmission rate more than 94%. The first segment of the DTL tank has been fabricated. This paper will introduce the design and R&D status of the linac. |
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MO204 | The Injector Systems of the FAIR Project | ion, emittance, heavy-ion, rfq | 31 |
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Funding: EU-Research Infrastructure Activity under the FP6 "Structuring the European Research Area" program (CARE, contract number RII3-CT-2003-506395); EU-INTAS Project Ref. no. 06-1000012-8782 |
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MO301 | Overview of the High Intensity Neutrino Source Linac R&D Program at Fermilab | cavity, proton, solenoid, rfq | 36 |
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Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. |
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MO302 | Overview of Recent RFQ Projects | rfq, ion, emittance, ion-source | 41 |
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RFQs are the new standard injector for a number of projects. The development of the 4-Rod RFQ structure has led to a number of interesting developments, which will be discussed with actual projects as examples. Recent work on the FAIR - p linac, the GSI - high charge state injector upgrade, the GSI - HITRAP, the new BNL - EBIS-RFQ, and the RFQ of the MSU - CW Reaccelerator will be presented and the status of these projects and will be discussed. |
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MOP003 | Performance of the Control System for the J-PARC Linac | controls, vacuum, cavity, klystron | 52 |
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Linac of J-PARC began to operate in November, 2006, and a achieved an initial performance in January, 2007. Afterwards, the beam supply to RCS begins, and it is operating extremely well with stability up to now. Here, the evaluation for comparison of the design and realities of architecture and performance of the LINAC control system are shown. Especially, the conceptual idea of function arrangement in the hierarchy of the control system architecture is shown. Now, the linac control system is in the second phase for the high power beam and reducing the beam loss, and the analysis of the system response identification for the high precision beam control is started. |
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MOP004 | Operating Experience of the J-PARC Linac | klystron, ion-source, ion, DTL | 55 |
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The J-PARC (Japan Proton Accelerator Research Complex) linac consists of an RFQ, a Drift Tube Linac and a Separated-type Drift Tube Linac. The beam commissioning of the linac started in November 2006 and 181 MeV acceleration was successfully achieved in January 2007. The linac has delivered beams to the 3 GeV Rapid Cycling Synchrotron for its commissioning, and then, the subsequent 50 GeV Main Ring Synchrotron and the neutron target commissioning. The linac uses 20 units of 324 MHz klystrons. As of May, 2008, the average number of filament hours exceeds 5,000 without serious troubles. The operating experience of the linac will be described in this paper. |
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MOP005 | Beam Test Results of the PEFP 20 MeV Proton Accelerator at KAERI | proton, DTL, rfq, klystron | 58 |
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A 20 MeV proton accelerator, which consists of a 50 keV injector, a 3 MeV RFQ and a 20 MeV DTL, has been tested by Proton Engineering Frontier Project (PEFP) at Korea Atomic Energy Research Institute (KAERI. The operation conditions are 20 MeV, 20 mA peak current, 50 μs pulse length with a 1 Hz repetition rate due to the limited radiation shielding. The accelerator was tuned to reach to the above operating conditions. Moreover, an irradiation facility with external beam has been installed to supply the proton beam for the user and irradiation test. In this paper, we present results from tuning operation and the irradiation tests. |
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MOP006 | Stability of Normal Conducting Structures Operation with High Average Heat Loading | cavity, coupling, DTL, simulation | 61 |
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Instead of proved application of superconducting structures for high energy part of intense linear proton accelerators, normal conducting structures are still considered for medium and low energy parts below 200 MeV. Operation with accelerating rate ~4 MeV/m and duty factor ~5% results for standing wave normal conducting structure in an average heat loading ~30 kW/m. Due to the high heat loading an operating mode frequency shift is significant during operation. In this paper conditions for field distribution stability against small deviations in time of individual cell frequencies are considered. For pi/2 structures these conditions were formulated by Y. Yamazaki and L. Young. General case of 0, pi/2 and pi operating modes is considered with common approach. |
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MOP007 | Status of the LINAC4 Project at CERN | klystron, injection, rfq, proton | 64 |
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Linac4 is a 160 MeV, 40 mA H- linear accelerator which will be the source of particles for all CERN proton accelerators from 2013. Its construction has started in 2008, as part of a program for the progressive replacement or upgrade of the LHC injectors during the next decade. Linac4 will initially inject into the PS Booster and at a later stage into a 4 GeV Superconducting Proton Linac (SPL), which could ultimately be upgraded to high duty cycle operation. For this reason accelerating structures, rf hardware and shielding of Linac4 are dimensioned for higher duty from the initial phase. Linac4 is normal-conducting, 80 m long and consists of an rf volume ion source, an RFQ, a beam chopping section and a cascade of three different types of 352 MHz accelerating structures. Its main design requirements are high reliability, high beam brightness and low beam loss. The accelerator will be housed in an underground tunnel on the CERN site, which can eventually be extended to the SPL, with equipment installed in a surface building above. The main parameters, the status of the main components, the planning, the project organisation and the civil engineering infrastructure are presented. |
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MOP008 | Development of a Cell-Coupled Drift Tube Linac (CCDTL) for Linac4 | coupling, cavity, DTL, alignment | 67 |
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The 352 MHz CCDTL will accelerate the Linac4 beam from 50 to 102 MeV. It will be the first CCDTL used in a proton linac. Three short DTL tanks, each having two drift tubes, are connected by coupling cavities and form a chain of 5 resonators operating in the stable π/2 mode. The CCDTL section is made of 7 such chains, each fed by a 1.3 MW klystron. Focusing quadrupoles are placed between tanks, easing their alignment with respect to a conventional DTL thus making the structure less sensitive to manufacturing errors. In order to validate the design and to develop the production technology, two prototypes have been constructed and successfully tested. The first prototype, built at CERN, consists of two half-cavities and one coupling cell, whereas the second, with two full cavities and one coupling cell, was built at VNIITF and BINP in Russia in the frame of an R&D contract funded by the ISTC Organisation. Both prototypes have been tested at CERN slightly beyond their nominal power level, at the design duty cycle of 10%. In this paper we present the results of high-power tests, the results of the technological developments prior to production, and the final design of the CCDTL. |
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MOP009 | Status of the RAL Front End Test Stand | ion, ion-source, rfq, diagnostics | 70 |
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High power proton accelerators (HPPAs) with beam powers in the several megawatt range have many applications including drivers for spallation neutron sources, neutrino factories, waste transmuters and tritium production facilities. The UK's commitment to the development of the next generation of HPPAs is demonstrated by a test stand being constructed in collaboration between RAL, Imperial College London, the University of Warwick and the Universidad del Pais Vasco, Bilbao. The aim of the RAL Front End Test Stand is to demonstrate that chopped low energy beams of high quality can be produced and is intended to allow generic experiments exploring a variety of operational conditions. This paper describes the current status of the RAL Front End Test Stand. |
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MOP010 | A Fast Chopper for the Fermilab High Intensity Neutrino Source (HINS) | impedance, vacuum, high-voltage, simulation | 73 |
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A fast chopper capable of kicking single 2.5 MeV H- bunches, spaced at 325 MHz, at rates greater than 50 MHz is needed for the Fermilab High Intensity Neutrino Source (HINS). Four 1.2 kV fast pulsers, designed and manufactured by Kentech Instruments Ltd., will drive a ~0.5m long meander made from a copper plated ceramic composite. Test results showing pulses from the prototype 1.2 kV pulser propagating down the meander will be presented. |
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MOP011 | An 8 GeV CW Linac With High Potential Beam Power | proton, cavity, cyclotron, injection | 76 |
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Modern technology allows us to consider operating an 8 GeV Linac in a cw mode to accelerate a high-current H- beam. By using appropriate accumulation rings, the linac could provide simultaneous beams for direct neutrino production, neutrino factories, fixed target experiments, and muon colliders. Several other unique accelerator applications could also be served and improved by the same continuous beam, including studies of energy production and nuclear waste reduction by transmutation, rare muon decay searches, and muon catalyzed fusion. The trade-offs between cw operation compared to pulsed operation that are considered include the maximum rf gradient and corresponding linac length or energy, the rf frequency, rf peak power and coupler requirements, and refrigeration. Methods for accumulating the beam from a cw linac to serve the special needs of the potential future Fermilab programs mentioned above are considered. In this paper we also examine the use of a cyclotron as a source of high current beams to reduce the cost and complexity of the linac front end. |
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MOP012 | High Power Test of Room Temperature Spoke Cavities for HINS at Fermilab | cavity, vacuum, controls, ion | 79 |
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The High Intensity Neutrino Source (HINS) R&D program at Fermilab will build a new 65 MeV test linac to demonstrate new technologies for application in a high intensity hadron linac front-end. The HINS warm section is composed of an ion source, a radio frequency quadrupole, a medium energy beam transport and 16 room temperature Crossbar H-type (RT-CH) cavities that accelerate the beam to 10 MeV (β=0.1422). The RT-CH cavities are separated by superconducting solenoids enclosed in individual cryostats. Beyond 10 MeV, the design uses superconducting spoke resonators. In this paper, we illustrate the completion of four RT-CH cavities and explain latest modifications in the mechanical and radio frequency (RF) designs. Cavities RF measurements and tuning performed at Fermilab are also discussed. Descriptions of the HINS R&D Facility including high power RF, vacuum, cooling and low level RF systems will be given. Finally, the history of RF conditioning and the results of high power tests of RT-CH cavities will be discussed. |
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MOP013 | Focusing Solenoids for the HINS Linac Front End | solenoid, focusing, dipole, alignment | 82 |
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Low energy part of the linac for the HINS project at Fermilab will use superconducting solenoids as beam focusing elements (lenses). While lenses for the conventional, DTL-type accelerating section of the front end require individual cryostats, in the superconducting accelerating sections solenoids will be installed inside rf cryomodules. Some of the lenses in the conventional and in the superconducting sections are equipped with horizontal and vertical dipole correctors. Lenses for the conventional DTL section are in the stage of production with certification activities ongoing at Fermilab. For the superconducting sections of the linac, several prototypes of focusing lenses were built and tested. Solenoid magnetic axis is used for alignment of the lenses in the transport channel of the accelerator. Corresponding technique has been developed at Fermilab and is used during certification of the production lenses for the DTL section. This report will summarize main design features, parameters, and test results of the focusing lenses of the linac. Magnetic axis alignment technique will also be described. |
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MOP014 | Status of the LANSCE Refurbishment Project | controls, klystron, high-voltage, neutron | 85 |
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The Los Alamos Neutron Science Center (LANSCE) accelerator is an 800 MeV proton linac that drives user facilities for isotope production, proton radiography, ultra-cold neutrons, weapons neutron research and various sciences using neutron scattering. The LANSCE Refurbishment Project (LANSCE-R) is an ambitious project to refurbish key elements of the LANSCE accelerator that are becoming obsolete or nearing end-of-life. The conceptual design phase for the project is funded and underway. The 5 year, $170M (US) project will enable future decades of reliable, high-performance operation. It will replace a substantial fraction of the radio-frequency power systems (gridded tubes and klystrons) with modern systems, completely refurbish the original accelerator control and timing systems, replace obsolete diagnostic devices, and modernize other ancillary systems. An overview of the LANSCE-R project will be presented. The functional and operating requirements will be discussed, the proposed technical solutions presented, and the plan for successful project execution while meeting annual customer expectations for beam delivery will be reviewed. |
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MOP015 | Operational Status and Future Plans for the Los Alamos Neutron Science Center (LANSCE) | neutron, proton, target, scattering | 88 |
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Funding: U. S. Department of Energy, National Nuclear Security Administration, Contract No. DE-AC52-06NA25396 LA-UR-08-03581 |
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MOP016 | Operational Experience of the SNS Front End and Warm Linac | cavity, target, beam-losses, DTL | 91 |
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Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. |
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MOP017 | The Proposed ISAC-III (ARIEL) Low-Energy Area and Accelerator Upgrades | ISAC, target, rfq, DTL | 94 |
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The ISAC-III proposal is a ten year plan to triple the amount of radioactive ion beam (RIB) time at the facility. The plan includes the addition of two new independent target stations with a design suitable for actinide target materials, a second 500 MeV proton beam line from the TRIUMF cyclotron and a new 50 MeV electron linac as a complementary driver to provide RIBs through photo-fission. The two new target stations will require a new mass-separator and low-energy beam-transport complex to deliver the additional beams to the ISAC experimental facilities. It is also proposed to install a new linear accelerator section to provide the capability for two simultaneous accelerated RIBs to experimenters. This paper will describe the proposed installations in the low-energy transport and accelerator sections of the ISAC complex. |
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MOP018 | ISAC-II Superconducting Linac Upgrade - Design and Status | cavity, cryomodule, ISAC, vacuum | 97 |
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The ISAC-II superconducting linac, operational since April 2006, adds 20 MV accelerating potential to the ISAC Radioactive Ion Beam (RIB) facility. An upgrade to the linac, in progress, calls for the addition of a further 20 MV of accelerating structure by the end of 2009. The new installation consists of twenty 141 MHz quarter wave cavities at a design beta of 11%. The cavities will be housed in three cryomodules with six cavities in the first two cryomodules and eight cavities in the last. A second Linde TC50 refrigerator has been installed and commissioned to provide cooling for the new installation. The design incorporates several new features as improvements to the existing cryomodules. They include a four point support frame for the cavity strongback, a modified LN2 circuit internal to the cryomodule and a new design for the mechanical motion of the rf coupling loop. A summary of the design and the current status of the cryomodule production and supporting infrastructure will be presented. |
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MOP020 | Post-Accelerator LINAC Development for the RIB Facility Project at VECC, Kolkata | cavity, ion, rfq, quadrupole | 103 |
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An ISOL (Isotope Separator On Line) type of RIB (Radioactive Ion Beam) facility* is being developed at our centre. The post-acceleration scheme will consist of a Radio Frequency Quadrupole** (RFQ) followed by a few IH LINAC cavities - further augumentation of energy using SC QWRs will be taken up at a later stage. The first two IH cavities have been designed for 37.6 MHz frequency like the preceding RFQ to keep the rf defocusing smaller. Explosively bonded copper on steel has been used for the fabrication of the IH cavities (1.72 m inner diameter, 0.6 m and 0.87 m lengths) and the inner components have been made out of ETP grade copper. Also, we have adopted an octagonal cavity structure to avoid fabrication complicacies. Thermal analysis of the cavities have been carried out and cooling configurations have been optimized accordingly to control the temperature rise of the LINACs. Detailed mechanical analysis has been carried out to reduce the deflection of the LINAC components under various loads. Design and fabrication aspects of these two cavities and results of the low power tests will be reported in this paper. * Alok Chakrabarti et. al. ; Proc. Part. Accl. Conf. 2005, pp-395. |
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MOP021 | Towards the Development of Rare Isotope Beam Facility at VECC Kolkata | rfq, ion, ion-source, target | 106 |
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An ISOL type Rare Isotope Beam (RIB) Facility is being developed at VECC, Kolkata around the existing K=130 room temperature cyclotron. The possibility of using the photo-fission production route using a 50 MeV electron linac is also being explored. The production target and a 6.4 GHz ECR based charge-breeder system will lead to two beam lines. The first one, a low energy beam transport (LEBT) line consisting of a 1.7 m long, 33.7 MHz RFQ, will be dedicated to material science & other ion-beam based experiments. The second, post-acceleration beam line will accelerate the beams to 1.3 MeV/u using a longer, 3.4 m RFQ and a series of IH linear accelerators. In the first stage, the beam energy will be about 400 keV/u using three modules of linacs. Subsequently the energy will be boosted to about 1.3 MeV/u. Some of the systems have already been installed and made operational. The LEBT line has been tested and stable ion beams accelerated to 29 keV/u with high efficiency in the 1.7 m RFQ. The 3.4 m RFQ and the first IH Linac tank are under installation in the post-acceleration beam line. In this contribution an overview of the present status of the facility will be presented. |
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MOP023 | Present Status of RIKEN Heavy-Ion Linac | ion, ion-source, rfq, acceleration | 112 |
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Present status of the RIKEN heavy-ion linac (RILAC) will be reported, which has been used for the injector to the RIKEN RI-beam factory since 2006 as well as for the nuclear physics experiments on superheavy elements since 2002. An alternative injector to the RI-beam factory, consisting of a superconducting ECR ion source, an RFQ, and three DTLs, will be also discussed. The construction of the ion source will be completed in this year and the extraction test of the beams will be started from 2009. An RFQ linac, originally developed for the ion implantation*, was given to RIKEN through the courtesy of Kyoto University. Reconditioning of this RFQ is underway, which will be modified for the new injector in the near future. *H. Fujisawa: Nucl. Instrum. Methods A345, 23 (1994). |
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MOP027 | Heavy Ion Injector for NICA/MPD Project | ion, rfq, electron, ion-source | 121 |
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Goal of the NICA/MPD project under realization at JINR is to start in the coming 5-7 years an experimental study of hot and dense strongly interacting QCD matter and search for possible manifestation of signs of the mixed phase and critical endpoint in heavy ion collisions. The Nuclotron-based Ion Collider fAcility (NICA) and the Multi Purpose Detector (MPD) are proposed for these purposes. The NICA collider is aimed to provide experiment with heavy ions like Au, Pb or U at energy up to 3.5 x 3.5 GeV/u with average luminosity of 1027 cm-2s-1. The existing Nuclotron injection complex consists of HV fore-injector and Alvarez-type linac LU-20. The LU-20 accelerates the protons up to the energy of 20 MeV and ions at Z/A=0.33 up to the energy of 5 MeV/u. New injector designed for efficient operation of the NICA facility is based on Electron String Ion Source providing short (< 10 ns) and intensive (up to 10 mA) pulses of U32+ ions, one section of RFQ and four sections of RFQ Drift Tube Linac accelerating the ions at Z/A=0.12 up to 6 MeV/u of the kinetic energy. General parameters of the injector are discussed. |
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MOP028 | A SC Upgrade for the REX-ISOLDE Accelerator at CERN | cavity, ion, cryomodule, acceleration | 124 |
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The High Intensity and Energy ISOLDE (HIE-ISOLDE) proposal is a major upgrade of the existing ISOLDE and REX-ISOLDE facilities with the objective of increasing the energy and the intensity of the delivered radioactive ion beam. For the energy increase a staged construction of a superconducting linac based on sputtered quarter wave cavities is foreseen downstream of the present normal conducting linac. A funded R&D program has been launched at the end of 2007 in order to prepare a full Technical Design Report covering all the issues of such a linac, including cavity prototyping and testing, cryomodule design, beam dynamics and beam diagnostics. We report here on the status and planning of the R&D activities for the SCREX-ISOLDE linac. |
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MOP029 | Beam Dynamics Studies for the SCREX-ISOLDE Linac at CERN | cryomodule, emittance, cavity, simulation | 127 |
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For the REX-ISOLDE upgrade a superconducting linac based on 101.28 MHz Quarter Wave Resonators (QWRs) is foreseen downstream the normal conducting (NC) linac. Currently the REX-ISOLDE linac can accelerate ions with a mass to charge ratio in the range of 3 < A/q < 4.5 and up to an energy of 3 MeV/u. The upgrade aims to reach a final beam minimum energy of 10 MeV/u for A/q=4.5 in two main stages. The first stage consists of installing two cryomodules loaded with 10 cavities able to reach 5.5 MeV/u at the end of the present linac and the second consists of replacing part of the existing NC linac and adding further cryomodules. We report here on a beam dynamics study of the accelerator for the two installation stages and the transport line to the experimental station. |
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MOP030 | Multiple User Beam Distribution System for FRIB Driver Linac | kicker, septum, simulation, emittance | 130 |
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Funding: Work was supported by DOE grant DE-FG02-04ER41324 *D.Gorelov, et al, proc of EPAC 2002, Paris, France, 2002. |
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MOP033 | The New EBIS RFQ for BNL | rfq, ion, alignment, emittance | 139 |
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A new RFQ is being built as a part of the new EBIS-linac at BNL. The RFQ accepts highly charged ions from the EBIS ion source with energy of 17 keV/u and ion currents of up to 10 mA. The operation frequency will be 100.625 MHz . The design had been optimized to get a rather short structure with LRFQ=3.1 m with moderate electrode voltages of UQ = 70 kV. The resonant insert has a cooled base plate and solid stems and vane-electrodes. The mechanical design is very stiff, with a precise base-structure. The top lid along the RFQ allows installation, alignment, inspection and maintenance. After the mechanical alignment of the electrodes the longitudinal electrode voltage distribution will be adjusted with tuning plates between the stems. The properties of the RFQ, the results of the tuning and the status of the project will be discussed. |
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MOP034 | Heavy Ion Radio-Frequency Quadrupole LINAC for VEC-RIB Facility | rfq, ion, dipole, ECRIS | 142 |
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Radio Frequency Quadrupole (RFQ) would be the first post accelerator for the upcoming Rare Isotope Beam (RIB) facility at Variable Energy Cyclotron Centre (VECC), India. A 33.7 Mhz RFQ capable of accelerating stable as well as RI beams of q/A > 1/16 to about 30 keV/u has already been constructed and operational since September 2005 . This has been installed in a dedicated beam line for doing material science experiments. Another 3.4 m long RFQ resonating at 37.6 Mhz and capable of accelerating heavy ion beams up to 98 keV/u have been fabricated which is to be installed in the beam line for the VEC-RIB facility. The physical parameters,rf test along with the measurements of accelerated beams from RFQ would be presented. |
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MOP039 | Design of a 2-Beam Type IH-RFQ Linac for High Intense Heavy Ion Beam Accelerations in Low Energy Region | cavity, rfq, ion, acceleration | 154 |
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In order to obtain high intensity ion beams from a linear accelerator (linac) stably, it is necessary to suppress the defocusing force due to the space charge effect. The defocusing force is extremely strong in low energy and high intensity beams. Therefore, high intensity ion beam acceleration in the low energy region is one of the most difficult conditions to achieve. One of the solutions is the relaxation of the defocusing force by dividing the high intensity beam into several beams. Thus, a multibeam IH type Radio Frequency Quadrupole (IH-RFQ) linac has been proposed for a high intensity injector system. In particular, we have been developing a two-beam type IH-RFQ cavity as a prototype of the multibeam type IH-RFQ by using computer code. This prototype has the capability of accelerating charged particles to mass ratio (q/A) greater than 1/6 from 5 keV/u up to 60 keV/u. The expected total output current is 87.2 mA for the total input beam current of 120 mA. |
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MOP040 | The Radiofrequency Quadrupole Accelerator for the Linac4 | rfq, cavity, emittance, quadrupole | 157 |
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The first stage of acceleration in Linac4, the new 160 MeV CERN H- injector, is a 352 MHz, 3 m long Radiofrequency Quadrupole (RFQ) Accelerator. The RFQ will capture a 70 mA, 45 keV beam from the rf source and accelerate it to 3 MeV, an energy suitable for chopping and injecting the beam in a conventional Drift Tube Linac. Although the RFQ will be initially operated at low duty cycle (0.1%), its design is compatible with higher duty cycle (10%) as the front-end for a possible high-intensity upgrade of the CERN linac facility. The RFQ will be of the brazed-copper design and will be built and assembled at CERN. Beam dynamics design allows for a compact structure made of a single resonant unit. Field symmetry is ensured by fixed tuners placed along the structure. In this paper we present the rf and mechanical design, the beam dynamics and the sensitivity to fabrication and to rf errors. |
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MOP042 | Complete RF Design of the HINS RFQ with CST MWS and HFSS | rfq, simulation, quadrupole, radio-frequency | 163 |
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Similar to many other linear accelerators, the High Intensity Neutron Source requires an RFQ for initial acceleration and formation of the bunched beam structure. The RFQ design includes two main tasks: a) the beam dynamics design resulting in a vane tip modulation table for machining and b) the resonator electromagnetic design resulting in the final dimensions of the resonator. The focus of this paper is on the second task. We report complete and detailed rf modeling on the HINS RFQ resonator using simulating codes CST Microwave Studio (MWS) and Ansoft High Frequency Structure Simulator (HFSS). All details of the resonator such as input and output radial matchers, the end cut-backs etc. have been precisely determined. Finally in the first time a full size RFQ model with modulated vane tips and all tuners installed has been built, and a complete simulation of RFQ tuning has been performed. Comparison of the simulation results with experimental measurements demonstrated excellent agreement. |
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MOP047 | Quadrupole Magnet Development for 132 MeV DTL of CSNS | DTL, quadrupole, cavity, alignment | 178 |
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In the China Spallation Neutron Source (CSNS) linac, a conventional 324 MHz drift-tube linac (DTL) accelerating an H- ion beam from 3 MeV to 132 MeV has been designed with 1.05% duty, consisting of 7 tanks with a total length of approximately 59.6 m. Currently, R&D work has focused on Tank 1, which will have 61 drift-tubes (DT) each housing an electro-magnet quadrupole (EMQ). Some EMQs with SAKAE coil have been fabricated and are under rigorous magnetic measurements by means of Hall probe, single stretched wire, rotating coil in order to verify the design specifications and fabrication technology. Magnetic measurements on the EMQs with iron cores made from the electrical-discharge machining (EDM) and the stacking method will be compared and discussed. Work has been implemented to reduce the alignment discrepancies between the geometric center of the DT and magnetic center of EMQ to within ± 50 μm. |
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MOP048 | DTL Tank Development of 132 MeV Linac for CSNS | DTL, quadrupole, vacuum, simulation | 181 |
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A conventional 324 MHz DTL has been designed for China Spallation Neutron Source (CSNS) to accelerate H- ion from 3 MeV to 132 MeV. There are 7 tanks in the DTL and currently the R&D of tank-1 is under proceeding. In our design, Tank-1 has a tilt field distributed partially in order to obtain most effective energy gain and low Kilpatric parameter. The tank has been fabricated and the manufacture technique was verified by the measurement results. Because of the difficulty of tuning a partial tilt field distribution, a complex rf measuring and tuning procedure are introduced. The analysis on calculating the perturbation in a new method is also proposed. |
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MOP049 | Drift Tube Linac Design and Prototyping for the CERN Linac4 | cavity, DTL, quadrupole, alignment | 184 |
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The Drift Tube Linac (DTL) for the new linear accelerator Linac4 at CERN will accelerate H- ion beams of up to 40mA average pulse current from 3 to 50MeV. It is designed to operate at 352.2MHz and at duty cycles of up to 10%, if required by future physics programmes. The accelerating field is 3.2MeV/m over the entire length. Permanent magnet quadrupoles are used as focusing elements. The 3 DTL cavities consist of 2, 4 and 4 segments of about 1.8m each, are equipped with 35, 41 and 29 drift tubes respectively, and are stabilized with post-couplers. Several new features have been incorporated in the basic design. The electro-magnetic design has been refined in order to reduce peak field levels in critical areas. The mechanical design aims at reducing the complexity of the mechanical structure and of the adjustment procedure. Drift tubes and holders on the tanks that are machined to tight tolerances do not require adjustment mechanisms like screws or bellows for drift tube positioning. A scaled cold model, an assembly model and a full-scale prototype of the first half tank have been constructed to validate the design principles. The results of metrological and rf tests are presented. |
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MOP051 | Linac Operations at Fermilab | booster, controls, LLRF, ion | 190 |
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Funding: Fermi Research Alliance under contract with the US Department of Energy |
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MOP052 | Re-phasing of the ISAC Superconducting Linac with Computed Values | cavity, emittance, ISAC, simulation | 193 |
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The ISAC superconducting linac is a fully operational machine that routinely provides beam to experiments. The linac consists of twenty superconducting independently phased cavities housed in five cryomodules. The initial tune is done manually aided by MATLAB routines to phase the linac and set the correct optics. From the initial tune we calculate the gradient at which each cavity operates based on the energy gain, the transit time factor and the geometry of the cavity itself. Then in the event of a gradient change of one or more cavities we can calculate the rf phase shift of each downstream cavity using the initial gradients, the known geometry of the entire linac and assuming linearity of the rf controls. This possibility has been investigated and we have demonstrated that the calculated phase shift can be implemented automatically thus avoiding a complete retune of the machine. In this paper we will present the calculations and the results of the online tests. |
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MOP053 | The SPIRAL 2 Superconducting Linac | cavity, cryomodule, vacuum, coupling | 196 |
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The SPIRAL2 superconducting linac is composed of 2 cryomodule families, basically one of low beta, called Cryomodule A, and one of high beta, called Cryomodule B. The low beta family is composed of 12 single cavity cryomodule. The high energy section is composed of 7 cryomodules hosting 2 cavities each. According to beam dynamics calculations all the cavities will operate at 88 MHz: one family at beta=0.07, and one at beta=0.12. The design goal for the accelerating field Eacc of the SPIRAL2 QWRs is : 6.5 MV/m. The configuration, cavities and cryomodule tests and status and the foreseen linac tuning will be described. |
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MOP054 | Experience with Stripping Carbon Foils in ALPI Super-Conducting Accelerator | cavity, ion, target, focusing | 199 |
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The superconducting linac ALPI, injected either by a XTU tandem or by the superconducting RFQ of PIAVE, is composed by 3 cryostats of bulk Nb cavities (β=0.056) and 13 cryostats of Nb sputtered on Cu cavities (β=0.11 and β=0.13), for a total of 64 cavities and an equivalent voltage of 35MV. The linac is build up in two branches connected by an achromatic and isochronous U-bend. In January 2007 a stripping station equipped with carbon foils of different thickness was placed after 6 cryostats, before the U-bend, to test the feasibility of acceleration and transport of a charge enhanced beam. The study was performed with 4 different beams (Ca, Ar, Zr and Xe) and a complete data analysis has been carried out. |
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MOP055 | Plans for a Superconducting H- Linac (SPL) at CERN | cavity, accelerating-gradient, proton, superconducting-cavity | 202 |
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As part of the upgrade of the LHC injector complex at CERN, the construction of a 4 GeV Superconducting Proton Linac (the SPL, in fact an H- accelerator) is planned to begin in 2012. Depending upon physics requests, it should be upgradeable to 5 GeV and multi-MW beam power at a later stage. The construction of Linac4, its low energy front end, has started at the beginning of 2008. A full project proposal with a cost estimate for the low power version of the SPL aimed at improving LHC performance has to be ready for mid-2011. As a first step towards that goal, essential machine parameters like rf frequency, cooling temperature and beam current have recently been revisited and plans have been drawn for designing and testing critical components. The SPL parameters are reviewed in the context of the CERN plans for upgrading the LHC injectors, and the foreseen developments during the next years are described. |
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MOP056 | The Status of the MSU Re-Accelerator (ReA3) | rfq, cavity, ion, diagnostics | 205 |
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The Re-accelerator being developed at the Michigan State University is a major component of a novel system proposed at the NSCL to first stop the high energy RIBs by the in-flight particle fragmentation method in a helium filled gas system, then increase their charge state with an Electron Beam Ion Trap (EBIT) charge breeder, and finally re-accelerate them to about 3 MeV/u, in order to provide opportunities for an experimental program ranging from low-energy Coulomb excitation to transfer reaction studies of astrophysical reactions. The accelerator system consists of a Low Energy Beam Transport (LEBT) with an external multi-harmonic buncher, a radio frequency quadrupole (RFQ) followed by a superconducting linac and a High Energy Beam Transport (HEBT). The superconducting linac will use quarter-wave resonators with bopt of 0.047 and 0.085 for acceleration and superconducting solenoid magnets for transverse focusing. The paper will discuss the recent progress of R&D and beam dynamics studies for the MSU Re-accelerator. |
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MOP057 | Linac Front-End Upgrade at the Cancer Therapy Facility HIT | rfq, solenoid, ion, emittance | 208 |
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A clinical facility for cancer therapy using energetic proton and ion beams (C, He and O) has been installed at the Radiologische Universitätsklinik in Heidelberg, Germany. It consists of two ECR ion sources, a 7 MeV/u linac injector, and a 6.5 Tm synchrotron to accelerate the ions to energies of 430 MeV/u. The linac comprises a 400 keV/u RFQ and a 7 MeV/u IH-DTL operating at 216.8 MHz and has been commissioned successfully in 2006. Yet the overall achieved transmission through the injector linac did not exceed 30% due to a mismatch of the beam at the RFQ entrance. Thus a detailed upgrade programme has been started to exchange the RFQ with a new radial matcher design, to correct the alignment and to optimize beam transport to the IH-DTL. The aim is to achieve a sufficient linac transmission above 60%. The new design of the RFQ has been finished in 2007 and the RFQ is currently in production. A test bench comprising a full ion source and LEBT setup to commission the RFQ in 2008 is under construction at Danfysik in Danemark. The current status of this upgrade programme will be reported in this contribution. |
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MOP059 | C6+ Ion Hybrid Single Cavity Linac with Direct Plasma Injection Scheme for Cancer Therapy | ion, cavity, rfq, heavy-ion | 211 |
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We succeeded to accelerate very intense carbon ions with the Direct Plasma Injection Scheme (DPIS) using Laser ion source in 2001 and 2004. The peak current reached more than 60 mA of C4+ and 18 mA of C6+ with pulse width of 2-3 x 10-6 sec. We believe that these techniques are quite effective for pulse accelerator complexes such as linear accelerator and synchrotron (heavy-ion cancer therapy). In heavy cancer therapy, carbon stripper section is rejected by accelerated C6+. One turn injection of high intensity (6 mA) C6+ ion is possible to enough in synchrotron. We study a new hybrid single cavity linac combined with radio frequency quadrupole (RFQ) electrodes and drift tube(DT) electrodes into a single cavity. The hybrid linac is able to downsize the linac system and reduce the peripheral device. Using DPIS with Laser ion source, we study POP hybrid single-cavity accelerator of C6+ for injector linac of C cancer therapy. The linac is designed to accelerate 6 mA C6+ ion from 40 keV/u to 2 MeV/u with YAG Laser ion source. We will present the design procedures of this hybrid linac, which is based on a three-dimensional electromagnetic field and particle orbit calculation. |
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MOP061 | The Feasibility of Low-Energy Electronuclear Power Plant | neutron, target, proton, DTL | 217 |
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Funding: Rosatom corp. |
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MOP062 | CW Proton Linac for the BNCT Application | rfq, cavity, ion, ion-source | 220 |
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A 2.5 MeV, 20 mA, cw, proton linac for the Boron Neutron Capture Therapy medical application is under construction at Linac Systems. The system consists of a 25 keV microwave ion source, a solenoid lens based low energy beam transport system, a 0.75 MeV RFQ linac, a 2.5 MeV RFI linac, and the necessary service systems. Because of the superb low energy capabilities of the RFI structure, the RFQ linac need only go to 0.75 MeV, resulting in a cavity dissipation of 74 kW for the RFQ section. Because of the high rf efficiency of the RFI structure, the cavity dissipation is only 35 kW for the RFI section. Extensive thermal studies have been made to accommodate these cw heat load. The beam power is 50 kW. The rf power system is designed for an average power output of 200 kW. The RFQ and RFI sections are coupled into a single resonant unit by a quarter-wave-stub resonant coupler. The combination is driven at a single point in the RFQ structure. The total length of the linac is 2.6 meters. The system is scheduled for completion by early fall (2008). |
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MOP063 | High-Power Lithium Target for Accelerator-Based BNCT | target, neutron, electron, gun | 223 |
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A 50 kW, water-cooled conical target for producing neutrons via the Li-7(p,n)Be-7 reaction at 2.5 MeV proton energy is under development at Linac Systems. This target is intended to accept a stationary, expanded CW beam with a diameter of 8 cm directly from an rf linac, resulting in peak surface heat flux of 7.5 MW m-2 (a 'waterbag' beam power distribution is assumed). The target is predicted to meet the intensity requirements for practical accelerator-based boron neutron capture therapy (BNCT), in concert with Linac Systems' CW RFI linac. Lithium metal targets present well-known physical and mechanical challenges at high beam power density that are addressed in our design. For instance, lithium melts at 180 C, necessitating efficient removal of heat at a low ΔT relative to ambient temperature. CFD modeling indicates that with 50 kW incident beam power, the peak lithium temperature can be held below 150 C with a water flow rate near 80 l min-1 and corresponding pressure drop of 170 kPa. The target prototype has been fabricated and is undergoing experimental thermal-hydraulic testing using an electron beam at the Plasma Materials Test Facility, Sandia National Laboratory. |
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MOP070 | Beam Dynamics and Error Studies of the SPIRAL2 Driver Accelerator | ion, target, quadrupole, cavity | 239 |
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After a detailed design study phase (2003-2004), the SPIRAL2 project at GANIL (Caen, France) was officially approved in May 2005, and is now in its phase of construction, with a project group including the participation of many French laboratories (CEA, CNRS) and international partners. The SPIRAL2 facility is composed of a multi-beam driver accelerator (5 mA/40 Mev deuterons, 5 mA/33 Mev protons, 1 mA/14.5 M ev/u heavy ions), a dedicated building for the production of Radiactive Ion Beams, the existing cyclotron CIME for the post acceleration of the RIBs, and new experimental areas. In this presentation we focus on the beam dynamics studies dedicated to the SPIRAL2 accelerator part of the project, from the ECR sources to the High Energy Beam Lines which have been recently updated. Various tuning examples will be presented for a variety of ions at different final energies, including error studies and beam losses evaluation. Accent is also put on the way we tune the accelerator with the computing code TRACEWIN, by using 3D electromagnetic maps and diagnostics corresponding to the real machine. |
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MOP073 | Parameter Design and Beam Dynamics Simulations for the IFMIF-EVEDA Accelerators | emittance, space-charge, quadrupole, rfq | 245 |
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One major subsystem of IFMIF (International Fusion Materials Irradiation Facility) is its accelerator facility, consisting of two 175 MHz CW accelerators, each accelerating a deuteron beam of 125 mA to the energy of 40 MeV. This high power beam, 10 MW, induces challenging issues that lead to plan a first phase called EVEDA (Engineering Validation and Engineering Design Activity), where only the portion up to 9 MeV of one accelerator will be constructed and tested. For these accelerators, the Parameter Design phase is about to be completed. This paper presents the status of these studies. Due to the very high beam intensity, particular efforts have been dedicated to minimise the space charge effect that can strongly increase the beam size via the halo, and the losses that can prohibit the requested hand-on maintenance. For that, Beam Dynamics simulations have been performed with 106 macro-particles, and a great vigilance has been granted to the emittance growth and the particles on the beam edge. Several possible solutions are presented, for which advantages and drawbacks to fulfil the specifications are discussed. |
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MOP075 | Benchmarking of Measurement and Simulation of Transverse RMS-Emittance Growth Along an Alvarez DTL | DTL, emittance, simulation, quadrupole | 251 |
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Funding: CARE, contract number RII3-CT-2003-506395) European Community INTAS Project Ref. no. 06-1000012-8782 |
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MOP077 | Beam Dynamics Studies on the EURISOL Driver Accelerator | target, rfq, emittance, proton | 257 |
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Funding: We acknowledge the financial support of the European Community under the FP6 "Research Infrastructure Action-Structuring the European Research Area" EURISOL DS Project Contract No. 515768 RIDS. |
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MOP078 | Transverse Beam Matching and Orbit Corrections at J-PARC LINAC | emittance, injection, beam-losses, DTL | 260 |
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In the design of the very high intensity proton beam of the J-PARC LINAC, precise control of transverse beam dynamics is extremely important for suppression of beam loss. We present results of transverse beam matching and orbit corrections. The linac has 7 matching sections, each of which consists of 4 quadrupole magnets and 4 wire scanners. At 5 matching sections, beam widths at wire scanners are designed to agree with each other. This condition is used in the newly developed algorithm of quadrupole field correction based on a transport model, XAL. Excellent matching performance has been achieved with mismatch factor less than 5% at beam current of 5 to 30 mA. Control of beam parameters from linac into RCS is important for RCS paint injection. Beam studies and comparison to a model have been performed with linac wire scanners combined with multi-wire proportional monitors in the injection line. Orbit corrections with dipole steering magnets based on XAL model have been performed. Orbit deviations were suppressed within 1 mm in horizontal and vertical directions in the whole linac. For these measurements, detailed comparisons to a multi-particle simulation will be shown. |
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MOP082 | Multipacting Simulation in RF Structures | simulation, multipactoring, electron, cavity | 266 |
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A new computer code for 3D simulation of multipacting phenomenon in axisymmetric and non-axisymmetric rf structures is presented. The goal of the simulation is to determine resonant electron trajectories and electron multiplication in rf structure. Both SW and TW structures of normal- and superconductivity have been studied. Simulation results are compared with theoretical calculations and experimental measurements. |
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MOP086 | End to End Beam Dynamics and RF Error Studies for Linac4 | DTL, emittance, klystron, booster | 275 |
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Linac4 is a normal conducting H- linac to be built at CERN as a new injector to the PS Booster and later on as a front end of a Superconducting Proton Linac (SPL). The layout consists of a H- rf source, a magnetic LEBT, a RFQ (accelerating the beam from 45 keV to 3 MeV), a chopper line, a conventional Drift Tube Linac (from 3 MeV to 50 MeV), a Coupled Cavity Drift Tube Linac (from 50 MeV to 100 MeV) and a pi-mode structure (PIMS, from 100 to 160 MeV), all operating at a frequency of 352 MHz. End-to-end beam dynamics simulations have been carried out in parallel with the codes PATH and TRACEWIN to optimise the design and performance of the accelerator and at the same time to guarantee a cross-check of the results found. An extensive statistical campaign of longitudinal error studies (static and dynamic) was then launched for validation of the proposed design and to assess the maximum level of RF jitter/inaccuracies (in both phase and amplitude) the system can tolerate before beam quality at injection in the PS Booster - and later in the SPL- is compromised. |
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MOP089 | Beam Dynamics and Wake-field Simulations for High Gradient ILC Linacs | cavity, simulation, emittance, wakefield | 284 |
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Higher order modes (HOMs) are simulated with finite element and finite difference computer codes for the ILC superconducting cavities currently under investigation for the ILC. In particular, HOMs in KEK's Ichiro type of cavity and Cornel University's Re-entrant design are focussed on in this work. The aim, at these Universities and laboratories, is to achieve an accelerating gradient in excess of 50 MV/m in 9-cell superconducting cavities whilst maintaining a high quality and stable electron beam. At these high gradients, electrical breakdown is an important cause for concern and the wakefields excited by the energetic electron beams are also potentially damaging to the beam's emittance. Here we restrict the analysis to performing detailed simulations, on emittance dilution due to beams initially injected with realistic offsets from the electrical centre of the cavities and due to statistical misalignments of the cavities. We take advantage of the latest beam dynamics codes in order to perform these simulations. |
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MOP091 | End-to-End Simulation of the SNS Linac Using TRACK | rfq, simulation, emittance, DTL | 290 |
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Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC-02-06CH11357. *"First TRACK Simulations of the SNS linac", B. Mustapha et al., in Proceedings of Linac-06 Conference, Knoxville, Tennessee, August 21-25, 2006. |
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MOP092 | Monte Carlo Simulation of Touschek Effects in a Linac Beam | scattering, electron, simulation, beam-losses | 293 |
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Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. |
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MOP093 | Study of IBS Effects for High-Brightness Linac Beams | scattering, emittance, lattice, brightness | 296 |
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Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. |
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MOP097 | Orthogonal Basis Function Approximation of Particle Distribution in Numerical Simulations of Beams | simulation, synchrotron | 299 |
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Funding: Work supported by the Department of Defense under contract N00014-06-1-0587 with Northern Illinois University. |
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MOP099 | An Innovative Graphic User Interface for PARMILA 2 | optics, DTL, drift-tube-linac, simulation | 305 |
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A new graphic user interface (GUI) has been created for the PARMILA 2 program. PARMILA 2 is an advanced version of the historical PARMILA program originally developed to design and model drift tube linear (DTL) accelerators. PARMILA 2 expands upon that capability to support the design and simulation of coupled cavity linear (CCL) accelerator structures, coupled-cavity drift tube linac (CCDTL) structures, superconducting accelerator structures, as well as DTL structures and transport lines that can include magnetic, radiofrequency and electrostatic beam optics elements. The Open Architecture Software Integration System, or OASIS, has been used to develop a custom module for the PARMILA 2 program that runs along with a suite of other optics codes in the Particle Beam Optics Laboratory (PBO Lab). OASIS development tools were utilized to define the innovative GUI for the PARMILA 2 module. Existing PARMILA 2 executables, including Parmila.exe, Lingraf.exe and readdst.exe, have been implemented via GUI commands utilizing other OASIS tools without any compilation or linking required. This paper presents an overview of the PARMILA 2 module and illustrates some of the GUI features. |
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MOP105 | Beam Dynamics and Wake-field Simulations for the CLIC Main Linacs | wakefield, emittance, cavity, damping | 320 |
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The CLIC linear collider aims at accelerating multiple bunches of electrons and positrons and colliding them at a center of mass energy of 3 TeV. These bunches are accelerated through X-band linacs operating at an accelerating frequency of 12 GHz. Each beam readily excites wake-fields in the accelerating cavities of each linac. The transverse components of the wake-fields, if left unchecked, can dilute the beam emittance. The present CLIC design relies on heavy damping of these wake-fields in order to ameliorate the effects of the wake-fields on the beam emittance. Here we present initial results on simulations of the long-range wakefields in these structures and on beam dynamics simulations. In particular, detailed simulations are performed, on emittance dilution due to beams initially injected with realistic offsets from the electrical centre of the cavities and due to statistical misalignments of the cavities. |
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MOP106 | Prediction of 4ν=1 Resonance of a High Intensity Linac | resonance, emittance, space-charge, simulation | 323 |
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The 4ν=1 resonance of a linac is found when the depressed tune is around 90 deg. It is observed that this fourth order resonance is dominating over the better known envelope instability and practically replacing it. Simulation study shows a clear emittance growth by this resonance and its stopband. Experimental measurement of the stopband of this resonance is proposed and conducted in early 2008 using the UNILAC at GSI. This study will serve as a excellent benchmarking. |
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MOP107 | Transverse Matching of the SNS Linac Based on Profile Measurements | emittance, DTL, beam-losses, neutron | 326 |
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Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. |
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MOP108 | Phase Law of a High Intensity Superconducting Linac | cavity, optics, focusing, beam-losses | 328 |
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Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
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MOP110 | Precise Control of Cooling Water System for Stabilization of 125 MeV Linac at LEBRA | electron, klystron, FEL, target | 331 |
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The 125 MeV linac at Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University has been used for generation of the near-infrared FEL and the Parametric X-ray Radiation (PXR). Currently the FELs from 0.86 to 6 microns and the PXR X-rays from 5 to 20 keV are available at LEBRA. Precise experiments using the light sources require a high stability in both the wavelength and the intensity of the lights. Though the linac was operated with the cooling water stabilized at 30 plus or minus 0.2 deg C, periodical fluctuation of the electron beam energy and the beam orbit suggested that the stability of the cooling water temperature was not sufficient. With this condition a large fluctuation (plus or minus 15%) was observed for the PXR intensity. After the improvement of the fine cooling water system and the water flow path, fluctuation of the cooling water temperature at the supply head of the accelerating tubes and the electromagnets was suppressed to within plus or minus 0.01 deg C. As a result of the improvement the PXR intensity fluctuation at the X-ray output port has been suppressed to within plus or minus 2% for the operation over several hours. |
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MOP111 | Control Systems for Linac Test Facilities at Fermilab | controls, EPICS, cryomodule, low-level-rf | 334 |
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Funding: *Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. |
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TU101 | Unique Features of the J-PARC Linac and Its Performance - Lessons Learnt | rfq, cavity, DTL, injection | 343 |
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The J-PARC linac has been successfully commissioned up to its design energy and almost design peak intensity. The unique methods and hardware features adopted in the J-PARC linac, such as the Cs-free H- ion source, macro-pulse generation method, stable one-shot operation method, rf chopper system related with the J-PARC 30mA-RFQ (Radio Frequency Quadrupole linac) design and its operation parameter, one-turn injection method into the following J-PARC RCS (Rapid Cycling Synchrotron), transverse matching using TRACE3D PMQ (Permanent Magnet Quadrupole) elements approximating the fringe field effects of the electro-quadrupole magnets, 2 cavity behavior of SDTL (Separated Drift tube Linac) fed with one Klystron and so on, will be reported in this talk. |
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TU102 | Status of the Construction of the SPIRAL2 Accelerator at GANIL | ion, cavity, cryomodule, rfq | 348 |
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The superconducting linac for the SPIRAL2 radioactive ion beam facility at GANIL is in the construction phase. The prototype components have been constructed and are being tested. A status report on the activities and future plans will be given. |
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TU103 | CERN Linac Upgrade Activities | proton, cavity, quadrupole, DTL | 353 |
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In its June 2007 session the CERN Council has approved the White Paper, which includes construction of a 160 MeV H- linear accelerator called LINAC4, and the study of a 4 GeV Superconducting Proton Linac (SPL). LINAC4 will initially replace LINAC2 as the injector to the PS Booster, improving its performance up to the levels required for producing the ultimate LHC luminosity. In a later stage, LINAC4 is intended to become the front-end of SPL in a renewed injection chain for the LHC, which could be progressively constructed over the next decade. After briefly introducing the motivations and layout of the new injector chain, the talk will present the characteristics of the new linacs and give an overview of their main technical features and the R&D activities pursued within the HIPPI Joint Research Activity. |
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TU201 | Linac R&D for the ILC Technical Design Report | cryomodule, linear-collider, collider, cavity | 359 |
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The International Linear Collider (ILC) Technical Design Report (TDR) is scheduled for publication in 2012. The TDR will include an updated ILC baseline technical design description, results from critical R&D programs in support of key parameter choices, and one or more models for a Project Implementation Plan with an associated value estimate. The focus of linac R&D is to:
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TU202 | ILC Siting in Moscow Region Near Dubna and ILC Related Activity at JINR | site, laser, diagnostics, cryomodule | 360 |
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The report presents the development of investigations on ILC siting in the Dubna region and ILC related activity at JINR. The report will describe the fields of activities ongoing to support the ILC at JINR. In addition, other linear accelerator activities at JINR will be summarized. |
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TU203 | Status and Future Prospects of CLIC | acceleration, damping, klystron, luminosity | 364 |
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The Compact Linear Collider (CLIC) is studied by a growing international collaboration. Main feasibility issues should be demonstrated until 2010 with the CLIC Test Facility (CTF3) constructed at CERN. The CLIC design parameters have recently been changed significantly. The rf frequency has been reduced from 30 GHz to 12 GHz and the loaded accelerating gradient from 150 MV/m to 100 MV/m. The consequences and logic of these changes will be reviewed and coherent parameter sets for a 3 TeV and a 500 GeV machine will be presented. The status and perspectives of the CLIC feasibility study will be presented with a special emphasis on experimental results obtained with CTF3 towards drive beam generation as well as progress on the high gradient accelerating structure development. The frequency change allows using high power X band test facilities at SLAC and KEK for accelerating structure testing at 11.4 GHz. The design gradient of 100 MV/m has been achieved in a recent test at SLAC with a very low breakdown-rate. |
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TU302 | Control, Stability and Staging in Laser Wakefield Accelerators | laser, controls, wakefield, plasma | 379 |
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Laser driven plasma wakefields have recently accelerated electron beams with quasi-monoenergetic energy distributions and with gradients of ~100 GV/m. Stabilization and optimization of beam quality are now essential. Recent LBNL experiments have demonstrated control of self trapping, resulting in reproducible bunches at 0.5 GeV. Further optimization has been demonstrated using plasma density gradients to control trapping, producing beams with very low absolute momentum spread at low energies. Simulations indicate that use of these beams as an injector greatly improves accelerator performance and experiments are now underway to demonstrate such staging, which will be a crucial technology for laser driven linacs. This talk will cover recent progress in LWFAs to obtain more reproducible, higher quality beams and also cover staging prospects for high energy laser linacs. |
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TUP001 | Status and Upgrade Plan of 250 MeV Linac at CLS | storage-ring, controls, injection, vacuum | 380 |
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Funding: CLS supports the upgrade of the 250 MeV linac. |
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TUP002 | ARIEL and the TRIUMF E-Linac Initiative, a 0.5 MW Electron Linac for Rare Isotope Beam Production | cavity, TRIUMF, electron, target | 383 |
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TRIUMF, in collaboration with university partners, proposes to construct a megawatt-class electron linear accelerator (e-linac) as a driver for U(γ,f) of actinide targets for nuclear astrophysics studies, and 9Be(γ,p)8Li for beta-NMR materials science. The e-linac is part of a broader proposal for an expansion of the TRIUMF rare isotope beams capability through a new facility to be named ARIEL. The e-linac design and prospects for funding are elaborated. |
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TUP003 | Proposal for a 15 MeV Superconducting Electron Linac for the DEINOS Project | laser, high-voltage, cavity, electron | 386 |
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The design of a 15 MeV, 2 kA peak current, electron accelerator for the DEINOS project is presented. It is dedicated to a new radiographic facility. The accelerator design is based on a dc photo-injector and a rf superconducting linac. Up to twenty electron micro-pulses, 100 ps time duration and 200 nC bench charge are emitted at 352 MHz repetition rate from a CS2Te photocathode and accelerated to 2.5 MeV in the dc diode before injection into a superconducting linac. A general description of the main accelerator components and the beam dynamics simulations are presented. |
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TUP004 | Status of the CTF3 Probe Beam Linac CALIFES | alignment, laser, klystron, dipole | 389 |
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The CLIC project based on the innovative Two Beams Acceleration concept is currently under study at CTF3 where the acceleration of a probe beam will be demonstrated. This paper will describe in details the status of the probe beam linac called CALIFES. This linac (170 MeV, 1 A) is developed by CEA Saclay, LAL Orsay and CERN. It will be installed in the new experimental area of CTF3 to deliver short bunches (1.8 ps) with a charge of 0.6 nC to the CLIC 12 GHz accelerating structures. The linac consists in an rf gun triggered by a laser beam, three LIL sections for bunching and acceleration, a beam diagnostic system and a single klystron with a pulse compression cavity and a dedicated rf network. We report new results of beam dynamic simulation considering the new CLIC parameters. We will give an estimation of the energy and phase deviation over the bunch train (140 ns long) by transient calculation of beam loading. Details about the fabrication of the rf gun, the cavity BPM, the HV modulator and the power phase shifter will be described. New results from laser system studies are discussed. The construction of CALIFES and the start of commissioning will be also reported. |
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TUP005 | The New Single Bunch Injector for ELSA | gun, cathode, single-bunch, solenoid | 392 |
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Since 1966 a Varian factored injector is in use at the accelerator complex of the University of Bonn serving several experiments to investigate the subnuclear structure of matter. This injector will have to be replaced for several reasons. The new injector will operate in a single bunch mode of 2 A beam current and is currently under construction. Also a 2 μs long pulse mode of 500 mA beam current will be available for ordinary accelerator operation for hadron physics experiments. Produced by a pulsed thermionic 90 kV gun, compression of the pulses is achieved by a 500 MHz prebuncher as well as one β-matching travelling wave buncher running at the linac frequency of 3 GHz. The injector has been designed and optimised using the software package EGUN and numerical simulations based on the paraxial differential equations. The single bunch mode will allow to investigate single bunch instabilities within the Helmholtz alliance "Physics at the Terascale". |
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TUP008 | Recent Changes to the e- / e+ Injector (Linac II) at DESY | target, positron, gun, electron | 401 |
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The Linac II at DESY consists of a 6A/150kV DC electron gun, a 400 MeV primary electron linac, a 800 MW positron converter, and a 450 MeV secondary electron/positron linac. The Particle Intensity Accumulator (PIA) is also considered part of the injector complex accumulating and damping the 50 Hz beam pulses from the linac and transferring them with a rate of 6.25 Hz or 3.125 Hz into the Synchrotron DESY II. The typical positrons rates are 6·1010/s. DESY II and Linac II will serve as injectors for the two synchrotron light facilities PETRA III and DORIS. Since PETRA III will operate in top-up mode, Linac availability of 98-99% are required. DORIS requires positrons for operation. Therefore during top-up mode positrons are required for both rings. In order to maintain its reliability over the operation time of the new facility PETRA III, the major components of the linac were renovated. Some components were redesigned taking into account experience from 30 years of operation. |
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TUP009 | Development of Timing and Control Systems for Fast Beam Switch at KEK 8 GeV Linac | controls, EPICS, positron, injection | 404 |
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The 8 GeV Linac at KEK provides electrons and positrons to Photon Factory (PF) and B-Factory (KEKB). Simultaneous top-up injections have been considered for both PF and KEKB rings in order to improve the injection efficiency and the stability. Fast beam-switching mechanisms are being implemented, upgrading the timing and control systems. While the present system provides precise timing signals for 150 devices, many of the signals will be dynamically switched using an event system. A new scheme has been developed and tested to enable double-fold synchronization between rf signals. Fast controls of low-level rf, beam instrumentation, a kicker, a gun, and beam operation parameters will also be upgraded. |
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TUP010 | Pulse-to-Pulse Mode Switching of KEKB Injector Linac | target, injection, positron, electron | 407 |
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KEKB injector linac supplies electron and positron beams to the KEKB storage rings and the synchrotron radiation facility rings (PF, AR) as well. Injection modes to these four destinations are switched by inserting and extracting positron generation target, changing magnet parameters and acceleration rf phases. To enable pulse-by-pulse switching in three out of the four modes, a pulse bend and pulse steerings are introduced. For DC quads and DC steerings, compatible beam-optical settings for beams of different beam-energy profiles are introduced. We have been performing beam studies to establish the pulse-by-pulse mode switching for daily beam operation. This paper describes a scheme for the mode switching and reports on an achievement of the beam studies. |
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TUP011 | Observations of Two Microbunches After a 180-Degree Arc Section at the KEKB Linac | electron, acceleration, injection, single-bunch | 410 |
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The KEKB linac continuously injects 8 GeV electron and 3.5 GeV positron beams into the KEKB rings: HER(high energy ring) and LER(low energy ring). The energy spread of the 8-GeV electron beam, which is accelerated to an 1.7 GeV 180-degree arc section and reaccelerated after this arc to a final energy of 8 GeV, is optimized by adjusting rf acceleration phases so as to assure efficient injections. When rf phases are slightly changed or drifted for some reasons, the beam not only shows larger energy spreads but also indicates two clusters on a beam profile monitor located at large energy dispersions. In this connection, a longitudinal beam profile was measured after the arc section with a streak-camera system utilizing an OTR(Optical Transition Radiation) bunch monitor. The observed bunch shape clearly shows a two-microbunch structure, suggesting that it could be generated in the arc section. Various experimental data as well as some CSR-related speculations are presented. |
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TUP012 | Design and Performance of Optics for Multi-energy Injector Linac | optics, injection, quadrupole, electron | 413 |
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KEK injector linac provides an injection beam for four storage rings, KEKB high energy electron ring(HER), low energy positron ring(LER), PF-AR electron ring, and PF electron ring. The injection beams for these rings have different energies and intensities. Recently, a requirement of simultaneous injection among these rings arises to make a top-up injection possible. Magnetic fields of DC magnets to confine the beam to the accelerating structures can not be changed between pulse to pulse, although the beam energy can be controlled by fast rf phase shifters of klystrons. This implies that a common magnetic field of the bending magnets and the quadrupole magnets should be utilized to deliver beams having different characteristics. Therefore, we have designed multi-energy optics for the KEKB-HER electron ring(8 GeV, 1 nC/pulse), the PF electron ring(2.5 GeV, 0.1 nC/pulse), and the KEKB-LER positron ring(3.5 GeV, 0.4 nC/pulse). We present a performance of the multi-energy injector linac. |
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TUP013 | Present Status of the KEK Injector Upgrade for the Fast Beam-Mode Switch | electron, injection, positron, target | 416 |
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The KEK electron/ positron linac is a 600 m long linear accelerator with the maximum energy 8 GeV electron and 3.5 GeV positron, and it is used as an injector for 4-rings (KEKB e-/ e+, PF, PF-AR). To increase the operation efficiency, we have an injector upgrade plan for a simultaneous injection operation. In this paper, we will present the operation scheme and the progress of upgrade project. |
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TUP014 | Present Status of the BEPCII Linac | injection, positron, electron, bunching | 419 |
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After the major upgrade in 2005, the BEPC injector linac has been commissioning and working smoothly for more than two years. A 2.1 GeV, 66 mA positron beam at the linac end has been obtained, and the highest injection rate into the ring of 80 mA/min. at 50 pps is reached, much higher than the design goal of 50 mA/min. The machine is working stable, the mal function was about 2% in the past two years, including the system test and the commissioning. |
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TUP016 | Status of an Automatic Beam Steering for the CLIC Test Facility 3 | quadrupole, lattice, emittance, simulation | 422 |
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An automatic beam steering application for CTF 3 is being designed in order to automatize operation of the machine, as well as providing a test-bed for advanced steering algorithms for CLIC. Beam-based correction including dispersion free steering have been investigated. An approach based on a PLACET on-line model has been tested. This paper gives an overview of the current status and the achieved results of the CTF3 automatic steering. |
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TUP018 | A 150 MeV Pulse Electron Linac with a 1 mA Average Current | electron, simulation, target, emittance | 428 |
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Funding: The present work is supported by the STCU project #P233 |
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TUP022 | RF Control and Longitudinal Beam Stability in Energy Recovery Linacs | beam-loading, cavity, controls, injection | 440 |
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Funding: Work partially funded by the European Commission in the Sixth Framework Program, contract no. 011935 EUROFEL-DS5, BMBF and Land Berlin. |
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TUP024 | Growth of Density Modulations in an Energy Recovery Linac Light Source due to Coherent Synchrotron Radiation and Longitudinal Space Charge | lattice, simulation, emittance, dipole | 444 |
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Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. |
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TUP029 | Electron Linac Based Coherent Radiation Light Source Project at OPU | radiation, electron, synchrotron, gun | 456 |
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The coherent synchrotron and transition radiation from electron bunches of a linear accelerator (linac) has continuous spectra in a submillimeter to millimeter wavelength range at relatively high peak-intensities. This light source has been applied to absorption spectroscopy by the authors for various kinds of matters with relatively strong light absorbance such as water and aqueous solutions. The other important characteristics of the coherent radiation are picosecond pulsed light and the high peak intensity of the electric field which can be introduced into matters. In our new project the light source using the pulsed coherent synchrotron and transition radiation will be developed by using the electron beams of a 18 MeV S-band electron linac at Osaka Prefecture University (OPU). The pulse shape of the radiation has been evaluated from the shape of the electron bunch. The system of the light source has been optimized and is under construction. The light source will be applied to the pulsed excitation of matters and to the pump-probe experiment using the electron beam and the coherent radiation. |
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TUP030 | Enhancements to the Diamond Light Source Pre-Injector Linac | klystron, booster, injection, single-bunch | 459 |
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Several modifications have been made to the 100 MeV Diamond Light Source pre-injector linac since initial commissioning in 2005 to improve beam stability and reliability and to increase the scope of operation of the system. Stability enhancements include tighter thermal control of low-level rf electronics, and a modified timing system for gun and linac operation. The linac has been optimised for multibunch filling of the storage ring and for single-bunch top-up operation with gun charge and timing determined by the state of the storage ring fill. Low-energy beam generation has been studied for fault-mode operation using one of the two rf stations, and a study of the options available for Diamond based on routine operation in this mode has been carried out. A summary of operational experience is presented, together with options for future development |
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TUP031 | Normal Conducting Options for the UK's New Light Source Project | klystron, emittance, cavity, FEL | 462 |
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A New Light Source project has been initiated to deliver a conceptual design for a next-generation light source facility in the UK. One option for such a light source is a free electron laser based on normal-conducting linac technology. This paper considers the different options available for waveband, gun and rf design of a normal-conducting linac FEL, and presents an overview of accelerating structure, modulator and klystron capability and availability. Particular attention is paid to the issue of the operation of a normal-conducting device at repetition rates of several hundred pulses per second. Overall capabilities and limitations of this approach are illustrated by reference to a start-to-end model of a suitable 3 GeV S-band linac design. |
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TUP032 | Simulations on Impact of the 3.9 GHz RF Section on the Multi Bunch Emittance at FLASH | cavity, emittance, damping, HOM | 465 |
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In order to compensate nonlinear distortions of the longitudinal phase space a rf section operated at three times the 1.3 GHz frequency of the existing TTF cavities is foreseen in the next phase of FLASH. Four modules of a nine-cell 3.9 GHz cavities will be installed right after the first accelerating module ACC1. These cavities could cause additional long-range wake fields which would affect the multi bunch (mb) beam dynamics leading to increase of the mb emittance. The mb emittance at the end of the linac is determined by the strength of the transverse wake fields in the rf system. These higher order modes appear after any off-crest moving bunch, which could happen either due to the cavity misalignment, or by transverse position fluctuations of the injected bunches. It is intended to damp them by means of the HOM couplers, which may reduce the damping time by factor of 105. The misalignment of the cavities offsets is expected to be by 0.5 mm rms. The paper describes the results of the simulations on the dependence of the mb emittance on cavities misalignment offsets and damping strength of the HOM couplers in the planned 3.9 GHz rf section. |
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TUP034 | Status of the 3rd Harmonic Systems for FLASH and XFEL in Summer 2008 | cavity, klystron, controls, electron | 471 |
|
|||
Ultra short bunches with high peak current are required for the creation of high brilliance coherent light in the VUV and X-ray range in undulators. At the Free Electron Laser in Hamburg (FLASH) and the European X-ray free electron laser (XFEL) they are obtained by a two stage bunch compression scheme based on acceleration off the rf field crest and transverse magnetic chicanes. The deviation of the rf field's sine shape from a straight line leads to long bunch tails and reduces the peak current. This effect can be eliminated by adding a third harmonic rf system. The paper gives an overview on the actual status of the beam dynamical examinations and as well on the development of the third harmonic sub-systems like modules, cavities and radio frequency systems for FLASH and the XFEL. |
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TUP039 | Status of the LINAC-800 Construction at JINR | electron, acceleration, gun, FEL | 480 |
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800 MeV electron linac (LINAC-800) is under construction at JINR. It will be used as a driver for Volume FEL and as a test bench for commissioning of elements of the ILC. Presently the electron injector is commissioned and the electron beam of 50 keV of the energy at current of about 15 mA was obtained. The results of the injector operation at nominal parameters (400 keV, 300 mA) and commissioning of the first accelerating section at 20 MeV are discussed. |
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TUP040 | Linear Accelerator for the PSI-XFEL FEL3 Beamline | FEL, emittance, gun, laser | 483 |
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In the planned PSI-XFEL facility, three FEL branches will supply coherent, ultra-bright, and ultra-short XFEL photons at wide wavelength range. FEL branch 1 will use a 6.0 GeV driving linac to generate hard X-rays from 0.1 nm to 0.3 nm, while FEL branch 2 is foreseen for X-rays from 0.3 nm to 1.0 nm. However, FEL branch 3 was designed to supply spatially as well as temporally coherent soft X-rays from 1.0 nm to 10 nm with the High-order Harmonic Generation based seeded HGHG scheme. To reach emittances of 0.2 mm.mrad and to squeeze consequently the whole facility within an 800 m long tunnel, PSI is presently developing an advanced low emittance gun (LEG) based on a 1 MV high gradient pulsed diode and field emission. The advanced LEG will be used to drive FEL branch 1 and 2, while an RF photoinjector will be used to drive the FEL branch 3. In this paper, we describe a CTF3 RF gun based injector, two bunch compressors, two diagnostic sections, and linacs for the PSI-XFEL FEL branch 3. |
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TUP041 | Superconducting Options for the UK's New Light Source Project | cryomodule, FEL, SRF, cavity | 486 |
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The UK's new light source project was officially launched on April 11th 2007, which will be based on advanced conventional and free electron lasers, with unique and world leading capabilities. User consulation exercises have already been initiated to determine the fundamental photon output requirements for such a machine. In order to match a nominal requirement for high repetition rates (extending up to 1 MHz), a series of superconducting rf (SRF) linac options have been investigated, reflecting varied beam loading conditions and subsequent high and low power rf solutions. |
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TUP046 | Linac Design for an Array of Soft X-Ray Free Electron Lasers | electron, FEL, emittance, lattice | 501 |
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Funding: This work was supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 |
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TUP048 | Identifying Jitter Sources in the LCLS Linac | quadrupole, klystron, collider, pick-up | 506 |
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The beam stability for the Linac Coherent Light Source (LCLS) Free-Electron Laser (FEL) at Stanford Linear Accelerator Center (SLAC) are critical for X-Ray power, pointing, and timing stability. Studies of the transverse, longitudinal, and intensity stability of the electron beam are presented. Identifying these sources by different methods like correlations, frequency spectrum analysis and other methods is critical for finally eliminating or reducing them. |
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TUP050 | Design and Optimization of Electron Bunch Acceleration and Compression | electron, wakefield, acceleration, cavity | 512 |
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Funding: The work of PE and JW was supported by the US Department of Energy under contract DE-AC02-76SF00515. The work of RAB and KJK was supported by National Science Foundation Award No. DMR-0537588. |
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TUP055 | Optimum Frequency and Gradient for the CLIC Main Linac Accelerating Structure | luminosity, wakefield, collider, accelerating-gradient | 527 |
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Recently the CLIC study has changed the operating frequency and accelerating gradient of the main linac from 30 GHz and 150 MV/m to 12 GHz and 100 MV/m, respectively. This major change of parameters has been driven by the results from a novel main linac optimization procedure. The procedure allows simultaneous optimization of operating frequency, accelerating gradient, and many other parameters of CLIC main linac. It takes into account both beam dynamics (BD) and high power rf constraints. BD constraints are related to emittance growth due to short- and long-range transverse wakefields. Rf constraints are related to rf breakdown and pulsed surface heating of the accelerating structure. The optimization figure of merit includes the power efficiency, measured as a ratio of luminosity to the input power as well as a quantity proportional to investment cost. |
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TUP056 | Beam Optics Studies and Commissioning Status of CTF3 | optics, quadrupole, status, closed-orbit | 530 |
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The objective of the CLIC Test Facility CTF3 is to demonstrate the feasibility issues of the CLIC two-beam technology. CTF3 consists of an electron linac followed by a delay loop, a combiner ring and a two-beam test area. One issue studied in CTF3 is the efficient generation of a very high current drive beam, used in CLIC as the power source to accelerate the main beam to multi-TeV energies. The beam current is first doubled in the delay loop and then multiplied by a factor four in the combiner ring by interleaving bunches using transverse deflecting rf cavities. The combiner ring and the connecting transfer line have been put into operation in 2007. In this paper we give the status of the commissioning, present the results of the combination tests and illustrate in some detail the beam optics measurements, including response matrix analysis, dispersion measurement and applied orbit correction algorithms. We discuss as well the observation of a vertical beam break-up instability which is due to the vertical transverse mode in the horizontal rf deflectors used for beam injection and combination. We outline the attempted methods to mitigate the instability and their effectiveness. |
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TUP065 | Demonstration of Multi-Pulse X-ray Generation via Laser-Compton Scattering Using Pulsed-Laser Super-Cavity | laser, cavity, electron, photon | 545 |
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Funding: Work supported by a Grant-In-Aid for Creative Scientific Research of JSPS (KAKENHI 17GS0210) and a Grant-In-Aid for JSPS Fellows (19-5789) |
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TUP066 | Commissioning of 10-MeV L-band Electron Linac for Industrial Applications | electron, klystron, gun, high-voltage | 548 |
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Funding: This work is supported by KAPRA and POSTECH Physics BK21 Program. |
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TUP071 | The ISAC-II SC-Linac Over Current Monitoring System | EPICS, ISAC, pick-up, ion | 557 |
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A personnel protection system is used to monitor the ion beam current into the experimental hall from the ISAC-II SC-linac. Two resonant capacitive pickups in the transfer line operate at the third harmonic of the bunch rate, 35.36 MHz, Ion charge, velocity and bunch width affect the sensitivity so calibration with dc Faraday cups is needed. Each monitor has a single conversion receiver with an active mixer. LO signals are provided by a frequency synthesizer locked to the accelerator synthesizer. The 1250 Hz IF signals are amplified, filtered with a 100 Hz bandwidth and amplitude detected. No image rejection is used as the background is due to on-frequency leakage from the RFQ and bunchers. An antenna in each monitor loosely couples a pulsed rf test signal to each pickup. These induced signals are mixed down to 11875 Hz, filtered, detected and used to provide watchdog signals. The measured currents are displayed through our EPICS control system which allows setting of the gain ranges, trip levels and conversion factors. The signals are also processed independently by dedicated ADC's and FPGA's to cause the Safety system to trip the beam if the current exceeds a nominal 10 nA. |
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TUP074 | Commissioning of the HITRAP Decelerator Using a Single-Shot Pepper Pot Emittance Meter | emittance, ion, rfq, electron | 564 |
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Funding: Work supported by BMBF under contract 06FY160I. *HITRAP webpage of AP division at GSI, http://www.gsi.de/forschung/ap/projects/hitrap/index_e.html |
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TUP078 | Development of Integrator Circuit for Charge Monitoring | controls, injection, storage-ring, electron | 576 |
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|||
At the SPring-8 1 GeV linac, a beam current or charge is measured by means of an integrator circuit. A signal from a current transformer is processed into an integrated voltage. The Fast Gated Integrator and Boxcar Averager Module (Stanford Research Systems) is presently used as the integrator. However we plan to expand a dynamic range and an integration time of the integrator. Because the noise level of the present integrator becomes too large for the expansion, we developed a low-noise and high-resolution integrator. Both the present and developed integrators have the same functions such as signal gating, accumulation of analog signal and sample hold. The principal noise of the integrator was found to be a switching noise of the gate switch. To reduce the switching noise a GaAs transfer switch SW-283-PIN (M/A-COM) was adopted as the gate switch. The experimental data of the developed integrator showed 1/10 of the noise level of the present integrator. |
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TUP079 | Operational Performance of a New Beam-Charge Interlock System for Radiation Safety at the KEKB Injector Linac | injection, controls, positron, radiation | 579 |
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A new beam-charge interlock system has been developed for radiation safety and machine protection at the KEKB injector linac. Although the previous software-based interlock system was working, it was replaced by the new hardware-based one. The new interlock system restricts the integrated amount of beam charges delivered to four different storage rings (KEKB e+, KEKB e-, PF, PF-AR) at six locations along the linac. When the integrated amount of beam charges exceeds a certain threshold level prescribed at each location, the beam-abort requests are directly sent through a twisted hardwire cable to the safety control system of the linac. The new interlock system boosted its reliability in comparison with the previous system. The full-scale operation of the new interlock system has been started since the end of March 2008. In this report we describe the operational performance of the new beam-charge interlock system. |
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TUP080 | Numerical Study of a New Bunch Length Monitor Utilizing a Detection of Electromagnetic Fields in Millimeter-Wave Region | radiation, vacuum, dipole, electron | 582 |
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A new nondestructive bunch-length monitor has been numerically investigated. The monitor detects electromagnetic fields generated through a ceramic gap of a vacuum pipe when a charged particle beam passes through the pipe gap. The frequency spectrum of the electromagnetic fields detected in wave zone spreads over a millimeter-wave length from a microwave length region for a short pulse beam with a bunch length of pico-second region. The frequency spectrum strongly depends on the bunch length of the relativistic charged beam if the geometrical structure of the pipe gap is fixed. The detection principle of the bunch-length monitor and some numerical analysis results applied to a single-bunch electron beam of the KEKB injector linac are described in this report. |
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TUP081 | Transient Beam Loading Compensation in CTF3 | beam-loading, electron, cavity, radiation | 585 |
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In the CLIC Test Facility 3 (CTF3), the strong coupling between the beam and the accelerating cavities (full beam loading) induces transient effects such that the head of the pulse is accelerated almost twice as much as the steady-state part of the pulse. The beam optics in the machine is tailored for the steady-state and not for the higher energy electrons, which are gradually lost. This can lead to inefficiency and contributes to the activation of the machine. A beam loading compensation scheme has been proposed to minimize this effect. By delaying appropriately the arrival time of rf pulse in accelerating cavities with respect to the beam, the transient energy can be brought close (to within a few percent) of the steady-state one. This paper presents the measurements done on CTF3 using time resolved energy measurements. |
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TUP082 | Bunch Length Measurements in CTF3 | pick-up, klystron, radiation, electron | 588 |
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The CLIC Test Facility CTF3, being built at CERN by an international collaboration, should demonstrate the feasibility of the CLIC two-beam technology by 2010. One of the issues addressed is the control of the electron bunch length in the whole complex. A bunch length measurement system with good resolution is therefore paramount. Two different systems are presently used in CTF3, based on microwave spectroscopy and on transverse rf deflectors, respectively. In the paper we describe the two systems, we discuss the different experimental methods used and present the results of the latest measurement campaigns. |
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TUP083 | Diagnostics and Measurement Strategy for the CERN Linac 4 | diagnostics, DTL, emittance, pick-up | 591 |
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Linac 4 is a 160 MeV H- linac which will become the new injector for CERN's proton accelerator chain. The linac will consist of 4 different rf structures, namely RFQ, DTL, CCDTL and PIMS running at 352.2 MHz with 2 Hz repetition rate and 0.4 ms pulse length. A chopper line ensures clean injection into the PS Booster. The combination of high frequency and a high-current, low-emittance beam calls for a compact design where minimum space is left for diagnostics. On the other hand, diagnostics is needed for setting up and tuning of the machine during both commissioning and operation. A measurement strategy and the corresponding choice of the diagnostic devices and their specific use in Linac4 are discussed in this paper. |
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TUP087 | Spectral and Charge-Dependence Aspects of Enhanced OTR Signals from a Compressed Electron Beam | gun, optics, radiation, cathode | 603 |
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Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357 |
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TUP092 | Laser-Based Profile and Energy Monitor for H- Beams | laser, electron, space-charge, ion | 615 |
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A beam profile and energy monitor for H- beams based on laser photoneutralization is being developed at Brookhaven National Laboratory for use on the High Intensity Neutrino Source at Fermilab. An H- ion has a first ionization potential of 0.75 eV and can be neutralized by light from a Nd:YAG laser (λ = 1064 nm). To measure beam profiles, a narrow laser beam is stepped across the ion beam removing electrons from the portion of the H- beam intercepted by the laser. A curved axial magnet field channels these electrons into a Faraday cup. To measure the energy spread of the electrons the laser position is fixed and the voltage on a screen in front of the cup is raised in small steps. We deduce the energy spread of the H- beam by deconvolving the electron spectrum into components from beam energy and from space-charge fields. Measurements are reported from experiments in the BNL linac MEBT at 750 keV. |
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TUP093 | Activities on High Brightness Photo-injectors at the Frascati Laboratories, Italy | FEL, emittance, laser, radiation | 618 |
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Funding: Work partially supported by the EU Commission in the sixth framework program. Contract No. 011935 EUROFEL and MIUR(Research Department of Italian Government). |
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TUP100 | The Optimization of a DC Injector for the Energy Recovery Linac Upgrade to APS | emittance, laser, gun, electron | 639 |
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Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. |
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TUP112 | Laser Timing Jitter Measurements at the Fermilab A0 Photoinjector | laser, cavity, electron, emittance | 664 |
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The Fermilab A0 Photoinjector is a 16 MeV high-intensity, low emittance electron linac used for advanced accelerator R&D. To achieve a high quality beam here it is important to maintain a stable laser in terms of both intensity and timing. This paper presents our measurement of the laser timing jitter, which is the random late or early arrival of the laser pulse. The seed laser timing jitter has been measured to less than 200 fs, by examining the power spectrum of the signal of a fast photodiode illuminated by it. The pulsed and pumped laser timing jitter has been measured with limited resolution to less than 1.4 ps, by examining the phase of a cavity impulsively excited by the signal from a fast photodiode illuminated by the laser pulse. |
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TUP117 | Development of Ultra-Low Emittance Injector for Future X-Ray FEL Oscillator | emittance, electron, cavity, gun | 676 |
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Funding: This work was supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC-02-06CH11357. *K.-J. Kim, Y. Shvyd'ko, and S. Reiche, to be published in Physical Review Letters (2008) |
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TUP120 | EBIS Preinjector Construction Status | ion, rfq, booster, electron | 685 |
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Funding: Work supported by the US Department of Energy and the National Aeronautics and Space Agency |
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WE101 | Energy Recovered Linacs | electron, emittance, laser, storage-ring | 688 |
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Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
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WE102 | High Average Current SRF Cavities | cavity, storage-ring, HOM, luminosity | 693 |
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Higher-order-mode (HOM) free superconducting (SC) single cell cavities were developed for the rf system of high luminosity storage ring colliders. Because of the successful results of these cavities under ampere-class beams, the components and technology of the SC cavities have immediately been applied to the middle sized storage rings upgrading the beam intensity by using a few SC cavities. Beside the storage ring rf, a SC based high intensity proton linac was commissioned for neutron physics. Recently, the feasibility study of energy recovery linacs has been carried at various laboratories aiming for the 4th generation light source. Status of these developments will be described. |
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WE103 | First Results from the ERL Prototype (ALICE) at Daresbury | gun, cavity, vacuum, cathode | 694 |
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The energy recovery linac prototype at Daresbury is now called ALICE (Accelerators and Lasers In Combined Experiments). This paper presents the results obtained in the past year, including the second (fourth) period of gun commissioning. Following the completion of gun commissioning in November 2007, the dedicated gun diagnostic line was removed and the electron gun attached to the booster cavity and hence the rest of the machine. The paper outlines some of the challenges experienced during the commissioning of both the photoinjector system and the superconducting cavities and presents the current status of the project as well as the very latest results from commissioning during the summer of 2008. |
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WE105 | RF Control of High QL Superconducting Cavities | cavity, controls, feedback, resonance | 704 |
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Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. |
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WE201 | RF Systems for CW SRF Linacs | SRF | 709 |
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The talk will provide an overview of the latest developments in rf systems for cw operated SRF linacs, such as CEBAF (in particular, 12 GeV Upgrade), Cornell ERL injector, ELBE, and ERLP at Daresbury. |
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WE202 | Operational Experience with High Power Beams at the SNS Superconducting Linac | cavity, beam-losses, neutron, injection | 710 |
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The latest operational experiences of the SNS 1 GeV superconducting H- linac will be presented as the beam power is increased and losses and beam halo become more important. The talk will include a comparison of the advantages and disadvantages of superconducting cavities. For example, issues arising from the use of different sets of SC cavities at different times will be described, along with the operational consequences on emittance and halo development. |
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WE204 | IH-DTL as a Compact Injector for a Heavy-Ion Medical Synchrotron | cavity, DTL, rfq, ion | 715 |
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An interdigital H-mode structure drift tube linac (IH-DTL) with alternating phase focusing (APF) has been developed downstream of a 4-vane type RFQ linac at the National Institute of Radiological Sciences as a compact injector for a heavy-ion medical synchrotron. The rf frequency of both linacs is 200 MHz, and the total length of the two linacs is less than 6 m. They can accelerate heavy ions having a charge to mass ratio of 1/3 up to 4 MeV/u. The accelerated current of 12C4+ is as high as 380 electric μA, and beam transmission through the APF IH-DTL is better than 96%. This compact injector-linac scheme might give a possible solution for a compact cancer therapy facility with heavy-ion beams. |
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WE205 | Commissioning and Operation of the Injector Linacs for HIT and CNAO | rfq, ion, DTL, ion-source | 720 |
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The Heidelberg Ion-Beam Therapy Centre (HIT) is the first dedicated clinical synchrotron facility for cancer therapy using energetic proton and ion beams (C, He and O) in Europe. The accelerator consists of a 7 MeV/u, 217 MHz injector linac and of a 430 MeV/u synchrotron. The installation and commissioning of the linac has been performed gradually in three steps for the ion sources and the LEBT, for the 400 keV/u RFQ, and for the 20 MV IH-type drift tube linac. The initial commissioning of the linac was finished successfully in December 2006, the commissioning of the synchrotron and of the high-energy beam lines with beam was finished for two fixed-beam treatment places in December 2007. Commissioning of the heavy-ion gantry is still going on. The results of the linac commissioning will be reported as well as the experience of more than one year of linac operation. To provide optimum conditions for patient treatment, an intensity upgrade programme has been initiated for the linac. A copy of the HIT linac is presently installed at the Centro Nazionale di Adroterapia Oncologica (CNAO) in Pavia, Italy. The status of the CNAO linac will be also reported. |
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TH102 | SRF Developments for Ion Acceleration | cavity, cryomodule, ion, niobium | 730 |
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The talk will provide an overview of the SRF development toward the acceleration of light and heavy ions including QWRs, HWRs, spoke and CH cavities. |
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TH103 | Developing Facilities for SNS Cryomodule Performance Improvements | cryomodule, cavity, radiation, shielding | 735 |
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Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy |
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TH202 | Heavy Ion Linac Booster at IUAC, New Delhi | niobium, cavity, acceleration, ion | 749 |
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The first module of the booster superconducting linear accelerator, consisting of a total of three modules, each having 8 quarter wave coaxial line bulk Nb resonators, has been commissioned at IUAC. During initial operation of the first linac module, the energy gain was found to be much lower due to various problems which are now identified and solved. After acceleration through the linac module and subsequent re-bunching using a superconducting Rebuncher, a 158 MeV silicon beam having pulse width of 400 ps was delivered to conduct nuclear physics experiments. The other two linac cryostats and the required 16 resonators to be installed in those two cryostats are in the final stage of fabrication. Work has progressed on a high current injector that would act as an alternate source of heavy ions for the superconducting linac. The first element of the high current injector is a high Tc superconducting magnet ECR source (PKDELIS) which would be followed by a room temperature radio frequency quadrupole accelerator and drift tube linac cavities. Prototypes of the RFQ working at 48.5 MHz, and that of the DTL working at 97 MHz, have been fabricated and are undergoing tests. |
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TH301 | Beam Dynamics Studies of the 8 GeV Linac at FNAL | cavity, simulation, focusing, proton | 760 |
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Funding: This work was supported by the U.S. Department of Energy, Office of Scince, under contracts number DE-AC02-06CH11357 and No. W-31-109-ENG-38. |
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TH303 | Towards a Model Driven Accelerator with Petascale Computing | simulation, beam-losses, rfq, emittance | 766 |
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Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC-02-06CH11357. |
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THP002 | The 1.3 GHz Superconducting RF Program at TRIUMF | cavity, TRIUMF, controls, ISAC | 774 |
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TRIUMF is proposing to build a 50 MeV electron linac as a driver to produce radioactive ion beams through photofission. The present design calls for the use of nine-cell 1.3 GHz Tesla type cavities. A 1.3 GHz Superconducting RF (SRF) program has been initiated with the goal to produce and test one nine cell cavity by the end of 2009. The program will utilize the existing clean room and SRF test facilities that support the ISAC-II heavy ion superconducting linac. A vertical cryostat has been modified with a new insert to allow single cell testing. Pumps for 2 K sub-atmospheric operation have been tested. A single cell fabrication program is being initiated with a local company. A RRR measurement program is on-going to test cavity welds. The goal of the 1.3 GHz upgrade is to not only produce cavities for the in house project but to broaden TRIUMF's technical base for future potential collaborations. The paper will report the progress and plans of the 1.3 GHz SRF program. |
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THP003 | Production and Testing of Two 141 MHz Prototype Quarter Wave Cavities for ISAC-II | cavity, ISAC, acceleration, TRIUMF | 777 |
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The medium beta section of the ISAC-II superconducting linac (β=5.7% and 7.1%) has been operational since April 2006 providing 20 MV of accelerating potential at 106 MHz. The ‘high beta' extension to the linac, in progress, will see the addition of twenty 141 MHz quarter wave cavities at β=11%. The design specification calls for cw operation at a voltage gain of at least 1.1 MV/cavity for no more than 7 W of power dissipated in the cavity. This operation point corresponds to challenging peak surface fields of 30 MV/m and 60 mT. The cavity design is similar in concept to the medium beta cavities except for the addition of a drift tube to render symmetric the accelerating fields. A prototyping and qualification program was initiated with PAVAC Industries Inc. of Richmond, B.C. Two full size models in copper and two in niobium have been completed. The niobium cavities have been warm and cold-tested and characterized for frequency, rf performance and mechanical stability. The cold performance of both cavities exceeds the specification and the final frequency is within tuning range. The design, fabrication details and test results will be presented. |
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THP004 | Performance of the ISAC-II 141 MHz Solid State Amplifier | cavity, ISAC, superconducting-cavity, rf-amplifier | 780 |
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The ISAC-II linac extension requires an additional 20 rf amplifiers to power twenty 141 MHz quarter wave superconducting cavities. Solid state amplifiers will be used for this extension as compared to tube amplifiers which have been employed for the existing ISAC-II linac section, operational since 2006. The amplifiers are specified to run with an output power of 600 W. The first amplifier of the production series has been tested for gain and phase linearity. Phase noise of this amplifier has been measured on a 141 MHz superconducting cavity and compared with phase noise measured with a tube amplifier. The test results and general rf, interlock and interface requirements are verified against tendered specification before series production of the remaining amplifiers can proceed. Benchmarking tests of the prototype amplifier will be reported. |
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THP005 | Tests of Wire Sublimations Very Close to SPIRAL 2 Superconducting Cavity | cavity, cryomodule, diagnostics, vacuum | 783 |
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The construction of the new Spiral 2 facility has started in Caen (France) at the National Heavy Ions Accelerator Center (GANIL). The SPIRAL 2 project is based on a multi-beam Superconducting Linac Driver delivering 5 mA deuterons up to 40 MeV and 1 mA heavy ions up to 14.5 MeV/u delivering different Radioactive Isotope Beams (RIB). The LINAC is composed of 2 cryomodule families. The low energy family (cryomodules A) is composed of 12 cryomodules housing a single cavity at beta=0.07. The "high" energy family (cryomodules B) is composed of 7 cryomodules housing 2 cavities at beta=0.12. In between cryomodules are located the focalisation quadrupoles and the diagnostic boxes. Strong beliefs forbid the use of interceptives diagnostics around superconducting cavities. We simulated the use of wires for diagnostics in the linac, sublimating 14 wires of tungsten, Niobium and carbon while operating the B cavity at full performances. The first results describe in this paper looks promising. |
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THP006 | 704 MHz High Power Coupler and Cavity Development for High Power Pulsed Proton Linacs | cavity, proton, vacuum, superconductivity | 786 |
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In the framework of the European CARE-HIPPI program we develop components for superconducting high pulsed power proton linacs at 704 MHz. We have designed, fabricated and tested a beta 0.47 5-cell elliptical cavity with an optimized stiffening to reduce its sensitivity to Lorentz forces. A fast piezo tuner has been developed in order to be able to operate the cavity in pulsed mode in our horizontal test cryostat CryHoLab. We also have carried out the development of a fundamental power coupler. It is designed to transmit a power up to 1 MW at a 10% duty cycle. A high power test area has been setup consisting of a 1.2 MW klystron, a pulsed high voltage power supply and a coupler test stand. |
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THP009 | RF and Cryogenic Tests of the First Beta 0.12 SPIRAL2 Cryomodule | cavity, cryomodule, vacuum, cryogenics | 792 |
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The SPIRAL2 project, installed in GANIL for Radioactive Ion Beam physics purposes requires the manufacturing of a multi beam driver. This driver is based on a superconducting Linac featuring two 88 MHz Quarter Wave Resonator families. IPN Orsay is in charge of the study and the assembly of the 7 high energy (beta = 0.12) cryomodules. Each cryomodule is composed of two QWRs, specified to operate at 4.2 K with a nominal accelerating gradient of 6.5 MV/m. A first qualifying cryomodule has been manufactured and tested at the beginning of 2008 in order to validate the resonator and the cryostat design before launching the serial production of the 6 remaining cryomodules. The paper presents the main results of this test and the cryomodule design in its final version. |
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THP010 | Influence of Piezo-Hysteresis and Resolution on Cavity Tuning | cavity, feedback, resonance, controls | 795 |
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Funding: Work partially funded by the EU Commission in the sixth framework programme, contract no 011935 EURO-FEL-DS5, BMBF and Land Berlin. |
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THP011 | Recent Developments on Superconducting CH-Structures and Future Perspectives | cavity, rfq, DTL, proton | 797 |
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Funding: GSI, BMBF contr. No. 06F134I, EU contr. No. 516520-FI6W, RII3-CT-2003-506395, EFDA/99-507ERB500CT990061 |
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THP017 | Use of Piezoelectric Actuator to Frequency Lock Superconducting Quarter Wave Resonator | controls, niobium, high-voltage, resonance | 815 |
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The frequency control of the superconducting quarter wave resonator at IUAC is currently accomplished by mechanical and electronic tuners which are operated in the time scale of seconds and hundreds of milliseconds to a few tens of microseconds respectively. Due to presence of microphonics, input rf power in the range 200-300 W was required to control the resonator for a typical field of 3-5 MV/m achieved with 6 watts dissipation. Implementation of a novel idea to damp the mechanical vibration with the help of SS-balls has helped to reduce rf power below 100 W. Though resonators are working fine at this power level, we are investigating whether further reduction of rf power is possible using a piezo actuator to control the drift of frequency. The piezo tuner working in hundreds of milli seconds range with the dynamic phase control scheme will share a substantial load from the electronic tuner. As a result, the resonator's phase lock loop will remain locked for less rf power. The initial test results of the piezo tuner will be presented. |
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THP019 | Third Harmonic Superconducting Cavity Prototypes for the XFEL | cavity, cryomodule, HOM, pick-up | 821 |
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The third harmonic cavities that will be used at the injector stage in the XFEL to linearize the rf curvature distortions and minimize beam tails in the bunch compressor are based on the rf structures developed at FNAL for the DESY FLASH linac. The design and fabrication procedures have been modified in order to match the slightly different interfaces of XFEL linac modules and the procedures followed by the industrial production of the main (1.3 GHz) XFEL cavities. A revision of the helium vessel design has been required to match the layout of the cryomodule strings, and a lighter version of the tuner has been designed (derived from the 1.3 GHz ILC blade tuner activities). The main changes introduced in the design of the XFEL cavities and the preliminary experience of the fabrication of three industrially produced and processed third harmonic rf structures are described here. |
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THP022 | SC Nb Sputtered QWRs for the REX-ISOLDE Accelerator at CERN: Prototype Design and Manufacturing | cavity, niobium, vacuum, simulation | 827 |
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The HIE-ISOLDE activity aims at the construction of a superconducting linac based on 101.28 MHz Nb sputtered Quarter Wave Resonators (QWRs), which will be installed downstream the present REX-ISOLDE linac. The present design considers two basic geometries of the cavities (geometric β0 = 6.26% and 10.84%) for which a mechanical, chemical treatment and Nb coating design study has been performed. We report here on the status of the prototype cavity and sputtering tests. |
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THP023 | Crab Cavities for Linear Colliders | cavity, dipole, collider, beam-loading | 830 |
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Crab cavities have been proposed for a wide number of accelerators and interest in crab cavities has recently increased after the successful operation of a pair of crab cavities in KEK-B. In particular crab cavities are required for both the ILC and CLIC linear colliders for bunch alignment. Consideration of bunch structure and size constraints favours a 3.9 GHz superconducting, multi-cell cavity as the ILC solution, whilst bunch structure and beam-loading considerations suggest an X-band copper travelling wave structure for CLIC. These two cavity solutions are very different in design but share complex design issues. Phase stabilisation, beam loading, wakefields and mode damping are special issues for these crab cavities. Requirements and potential design solutions will be discussed for both colliders. |
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THP025 | Superconducting Quarter-Wave Resonators for the ATLAS Energy Upgrade | cavity, cryomodule, niobium, coupling | 836 |
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A set of six new 109 MHz β=0.15 superconducting quarter-wave resonators (QWR) has been built at ANL as part of an upgrade to the ATLAS superconducting heavy-ion linac. The final cavity string assembly will also use many of the techniques needed for the next generation of large high-performance ion linacs such as the U.S. Department of Energy's FRIB project. Single-cavity cold tests at T=4.5 K have been performed for three cavities with moveable coupler, rf pickup, and VCX fast tuner as required for the full 6-meter cryomodule assembly. The average maximum accelerating gradient of 4 cavities (3 new + 1 prototype), is EACC=11.2 MV/m (BPEAK=65 mT). Clean cavity string assembly techniques, required here and for most future SRF ion linacs, are fairly well developed. Details on cavity performance including high-field cw operation, microphonics and fast tuning are presented. |
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THP026 | Surface Processing Facilities for Superconducting RF Cavities at ANL | cavity, controls, cathode, niobium | 839 |
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New SRF cavity processing systems at ANL, including those for electropolishing (EP), high-pressure water rinsing (HPR), and single-cavity clean room assembly have been developed and operated at ANL for use with cavities for a range of electron and ion linac applications. Jointly with FNAL, systems for 1.3 GHz single- and multi-cell elliptical cavities for the linear collider effort have been developed. New systems for use with low-beta TEM-class cavities have also been built and used to process a set of new quarter-wave resonators as part of an upgrade to the ATLAS heavy-ion accelerator at ANL. All of the new hardware is located in a 200 m2 joint ANL/FNAL Superconducting Cavity Surface Process Facility (SCSPF) consisting of two separate chemical processing rooms, a clean anteroom, and a pair of class 10 and 100 clean rooms for HPR and clean assembly. Results of first cold tests for elliptical and TEM-class cavities processed in these facilities are presented. |
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THP030 | High Gradient Test Results of 325 MHz Single Spoke Cavity at Fermilab | cavity, vacuum, simulation, accelerating-gradient | 851 |
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The High Intensity Neutrino Source (HINS) project represents the current effort at Fermilab to develop 60 MeV Proton/H- Linac as a front end for possible use in the Project X. Eighteen superconducting β=0.21 single spoke resonators (SSR), operating at 325 MHz, comprise the first stage of the HINS cold section. Two SSR cavities have now been fabricated in industry under this project and undergone surface treatment that is described here. We report the results of high gradient tests of the first SSR in the Vertical Test System (VTS). The cavity successfully achieved accelerating gradient of 13.5 MV/m; higher than the design operating gradient of 10 MV/m. The history of multipacting and conditioning during the VTS tests will be discussed. Experimental measurements of the cavity mechanical and vibration properties including Lorenz force detuning and measurements of X-rays resulting from field emission are also presented. |
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THP047 | Design of the MEBT Rebunchers for the SPIRAL2 Driver | cavity, rfq, simulation, ion | 894 |
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The SPIRAL2 project uses a RFQ, normal conducting rebunchers and a superconducting linac to accelerate high intensity beams of protons, deuterons and heavier ions. All cavities work at 88 MHz, the beta after of the RFQ 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 holes (60 mm) and providing up to 120 kV of effective voltage. |
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THP048 | RF Power Amplifiers for the SPIRAL2 Driver: Requirements and Status | cavity, rfq, controls, LLRF | 897 |
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The SPIRAL2 project uses an RFQ, normal conducting rebunchers and a superconducting linac to accelerate high intensity beams of protons, deuterons and heavier ions. All cavities work at 88 MHz, are independently phased and powered by amplifiers whose power ranges from a few kW to 250 kW. The paper describes the amplifier requirements, the proposed solutions and their status. |
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THP056 | Improvement in the ACS Cavity Design for the J-PARC Linac Energy Upgrade | coupling, cavity, simulation, background | 915 |
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The ACS (Annular-ring Coupled Structure) cavities were under development for the J-PARC Linac from 190 MeV to 400 MeV. We have fixed the cavity specification, taking into account the results of the high-power conditioning and the fabrication experience. The mass production of the ACS with a tight time schedule is now an issue, since the user community strongly requests the beam power upgrade as early as possible. Therefore, the design and the fabrication process of the ACS cavity have been reexamined on the basis of the experience, stored during the course of the fabrication and the tuning of the prototype ACS tanks. Here, we also discussed about the key issues on the mass production with a manufacturer. The cavity shape, that required complicated machining, was simplified to some extent, while the frequency tuning strategy was reconsidered to reduce the production period. The paper describes these recent activities on the ACS development. |
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THP057 | Development of RF Cavities for the SHB System of the L-band Electron Linac at Osaka University | cavity, resonance, electron, single-bunch | 918 |
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Funding: This research is partly supported by the accelerator support program to universities conducted by the High Energy Accelerator Research Organization in Japan. |
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THP059 | The Cut Disk Structure Parameters for Medium Proton Energy Range | coupling, septum, proton, impedance | 924 |
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For intense proton beam acceleration the structure aperture diameter should be ~30 mm. With such aperture room temperature coupled cell accelerating structures have the maximal effective shunt impedance Ze at operating frequency ~650 MHz. For this frequency well known Side Coupled Stricture (SCS), Disk and Washer Structure (DAW), Annular Coupled Structure (ACS) have large transversal dimension, leading to essential technological problems. The Cut Disk Structure (CDS) has been proposed to join high Ze and coupling coefficient kc values, but preferably for high energy linacs. In this report parameters of the four windows CDS option are considered at operating frequency ~700 MHz for proton energy range from 80 MeV to 200 MeV. The cells diameter ~30 cm and kc ~0.12 result naturally, but Ze value is of (0.7-0.9) from Ze value for SCS (kc=0.03). Small cells diameter opens possibility of CDS applications for twice lower frequency and structure parameters at operating frequency ~ 350 MHz are estimated too. Cooling conditions for heavy duty cycle operation are considered. |
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THP060 | Room Temperature Accelerating Structure for Heavy Ion Linacs | cavity, DTL, rfq, ion | 927 |
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In this report we consider room temperature DTL structure for heavy ions acceleration in energy range 150 keV/u - 400 keV/u. The structure design is based on known and proven solutions. Due to design idea, the structure has no end wall problem. It allows flexible segmentation in cavities and transverse focusing elements placing outside cavity. As compared to well known IH DTL, considered structure has smaller transverse dimensions and is designated for lower operating frequency. The structure promises high rf efficiency - with careful elements optimization calculated effective shunt impedance value is higher than 1.0 GOhm/m for operating frequency ~ 70 MHz, E~150 keV/u. |
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THP062 | Design of an X-Band Accelerating Structure for the CLIC Main Linac | damping, HOM, accelerating-gradient, impedance | 933 |
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The rf design of an accelerating structure for the CLIC main linac is presented. The structure is designed to provide 100 MV/m averaged accelerating gradient at 12 GHz with an rf-to-beam efficiency as high as 27.7%. The design takes into account both aperture and HOM damping requirements coming from beam dynamics as well as the limitations related to rf breakdown and pulsed surface heating. |
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THP063 | A New Local Field Quantity Describing the High Gradient Limit of Accelerating Structures | accelerating-gradient, vacuum, site, status | 936 |
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A new local field quantity which gives the high gradient performance limit of accelerating structures in the presence of vacuum rf breakdown is presented. A model of the breakdown trigger based on the pulsed heating of a potential breakdown site by the field emission currents and driven by a new field quantity, a modified Poynting vector, has been derived. The field quantity Sc takes into account both active and reactive power flow on the surface. This new quantity has been evaluated for many X-band and 30 GHz rf tests, both travelling wave and standing wave, and the value of Sc achieved in the experiments agrees well with analytical estimates. |
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THP064 | Development Status of the Pi-Mode Accelerating Structure (PIMS) for Linac4 | cavity, coupling, impedance, vacuum | 939 |
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The high-energy section of Linac4, between 100 and 160 MeV, will be made of a sequence of 12 seven-cell accelerating cavities of the Pi-Mode Structure (PIMS) type, resonating at 352 MHz. Compared to other structures used in this energy range, cavities operating in pi-mode with a low number of cells have the advantage of simplified construction and tuning, compensating for the fact that the shunt impedance is about 10% lower because of the lower frequency. Field stability in steady state and in presence of transients is assured by the low number of cells and by the relatively high coupling factor of 5%. Standardising the linac rf ystem to a single frequency is considered as an additional economical and operational advantage. The mechanical design of the PIMS will be very similar to that of the 352 MHz normal conducting 5-cell LEP accelerating cavities, which have been successfully operated at CERN for 15 years. After reviewing the basic design principles, the paper will focus on the tuning strategy, on the field stability calculations and on the mechanical design. It will also report the results of measurement on a cold model and the design of a full-scale prototype. |
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THP065 | Shunt Impedance Studies in the ISIS Linac | DTL, impedance, simulation, cavity | 942 |
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The ISIS linac consists of four DTL tanks that accelerate a 50 pps, 20 mA H- beam up to 70 MeV before injecting it into an 800 MeV synchrotron. Over the last decades, the linac has proved to be a strong and reliable injector for ISIS, which is a significant achievement considering that two of the tanks are more than 50 years old. At the time the machine was designed, the limited computing power available and the absence of 3D electromagnetic (EM) simulation codes, made the creation of a linac optimized for power efficiency almost impossible, so from this point of view, the ISIS linac is quite simple by today's standards. In this paper, we make a shunt impedance comparison study using the power consumption data collected from ISIS and the results obtained when simulating each of the four DTL tanks with 2D and 3D EM codes. The comparison will allow us to check the accuracy of our simulation codes and models and to assess their relative performance. It is particularly important to benchmark these codes against real data, in preparation for their use in the design of a proposed new linac, which will replace the currently aging ISIS injector. |
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THP069 | Design and Test of the Triple-Harmonic Buncher for the NSCL Reaccelerator | cavity, rfq, emittance, simulation | 948 |
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To meet the requirement of a small output longitudinal beam emittance from the reaccelerator, a triple-harmonic buncher operating at the fundamental frequency of 80 MHz upstream the Radio Frequency Quadrupole (RFQ) linac has been designed, manufactured and tested at the National Superconducting Cyclotron Laboratory (NSCL). The buncher consists of two coaxial resonators with a single gridded gap. One cavity provides both the fundamental and the third harmonic simultaneously with l/4 and 3l/4 modes respectively, while the other for the second harmonic with a l/4 mode. This buncher combines the advantages of using high quality factor resonator and only a pair of grids. Details on design considerations, electromagnetic simulations, and test results are presented. |
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THP070 | Surface-Loss Power Calculations for the LANSCE DTL | DTL, cavity, vacuum, drift-tube-linac | 951 |
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The surface losses in the drift-tube linac (DTL) tanks 3 and 4 of the LANSCE linear accelerator are calculated using 3-D electromagnetic modeling with the CST MicroWave Studio (MWS). The results are used to provide more realistic power estimates for the 201.25 MHz rf upgrade design within the LANSCE-R project. We compared 3-D MWS results with those from traditional 2-D Superfish computations for DTL cells and their simplified models and found differences on the level of a few percent. The differences are traced to a 3-D effect consisting in a redistribution of the surface currents on the drift tubes (DT) produced by the DT stem. The dependence of MWS results on the mesh size used in computations is also discussed. |
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THP071 | Efficient Low-Beta H-Mode Accelerating Structures with PMQ Focusing | focusing, cavity, beam-losses, quadrupole | 954 |
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We are developing high-efficiency room-temperature rf accelerating structures for beam velocities in the range of a few percent of the speed of light by merging two well-known ideas: H-mode cavities and the transverse beam focusing with permanent-magnet quadrupoles (PMQ). Combining electromagnetic 3-D modeling with beam dynamics simulations and thermal-stress analysis, we have found that the H-mode structures with PMQ focusing provide a very efficient and practical accelerator for light-ion beams of considerable currents. Such accelerating structures following a short RFQ can be used in the front end of ion linacs or in stand-alone applications such as a compact deuteron-beam accelerator up to the energy of a few MeV. |
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THP073 | Progress in L-Band Power Distribution System R&D at SLAC | cavity, coupling, cryomodule, acceleration | 960 |
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Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515. |
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THP076 | Last SPIRAL 2 10 kW CW RF Coupler Design | cryomodule, cavity, simulation, resonance | 969 |
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The first tests of the SPIRAL 2 coupler have been done successfully in the B-cryomodule of the SPIRAL2 linac. It led to an updated design. We present the new design as well as the results of the last test and conditioning. |
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THP078 | High Power RF Supplies for the FAIR Injector Linacs | klystron, proton, LLRF, rfq | 975 |
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During the LINAC conference in Knoxville 2006 the operating frequency of the FAIR proton linac was fixed at 325.224 MHz. Even though the six CH-Structures need slightly different rf levels, the proton linac will be equipped with identical rf power sources. That applies although for the RFQ structure. To supply the FAIR accelerators with a good beam quality by the UNILAC as the high current heavy ion injector for FAIR, as well as an high duty factor accelerator for nuclear physics experiments, different upgrades and modifications have to be made at the rf components. In addition there has to be an upgrade for a planned 50% duty cycle mode, higher beam load within the post-stripper section as well as the provision of an excellent rf operation for the next 30 years. Discussions on possible collaborations with CERN in terms of LLRF and the combining of the procurement for tube amplifiers for bunching cavities are on the way. This paper describes the actual status of the proton linac rf system and the future requirements for the existing UNILAC rf systems. |
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THP080 | Elimination of Parasitic Oscillations in RF Tube Amplifier for High Power Application | cavity, ion, simulation, controls | 981 |
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For the heavy ion therapy center HIT in Heidelberg a 1.6 MW power amplifier for 217 MHz was built to supply the 7 MeV/u IH cavity. The inherent parasitic oscillations of the RF tube increases rapidly the anode current until the system switches off. For the elimination of those parasitic oscillations ferrite material is used. The electro magnetic fields are simulated to find an optimal positioning of the ferrite material in the anode cavity such that only the parasitic oscillations are attenuated without affecting the fundamental mode. |
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THP081 | Development of All Solid State Bouncer Compensated Long Pulse Modulators for LEP 1MW Klystrons to be Used for LINAC4 Project at CERN | klystron, high-voltage, simulation, controls | 984 |
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Funding: Department of Atomic Energy, India. The work is done under DAE CERN Collaboration under NAT Protocol. |
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THP085 | Cooling System Design of Compact Klystron Modulator Power Supply in the XFEL Project at SPring-8 | klystron, power-supply, cathode, high-voltage | 987 |
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A klystron modulator power supply for XFEL project at SPring-8 has been developed, which concepts are a compact body, a low noise, and a good stability. The cooling system of the power supply is one of the most important key for the stable modulator. For example, temperature change of insulation oil in the tank caused drift of the klystron voltage, and higher oil temperature deteriorates insulation oil and electric components. We adopted simple and compact cooling systems utilizing natural conviction cooling, because of low costs, limited space, and maintenance free. In order to estimate the requisite cooling ability, we designed four types of cooling panels and measured the natural conviction heat transfer coefficient between the oil and each cooling panels. Using the results, we designed cooling systems composed of water cooling panels placed on the side walls and a water pipe hanged from the ceiling panel. The temperature of the inner oil of the power supply in the rated operation was suppressed below 43 degree C, which is agreed with our expectation. In this paper we present the design and ability of the power supply, and the key point of oil cooling. |
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THP087 | Quarter-Wave-Stub Resonant Coupler | coupling, controls, rfq, cavity | 993 |
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Most small proton and other ion linacs involve two different linac structures, namely an RFQ linac section and some other, more efficient, linac structure, such as the Drift Tube Linac (DTL), the interdigital (Wideroe) linac, or the Rf Focused Interdigital (RFI) linac. Such linacs can benefit a lot by being resonantly coupled into a single resonant unit. The resonantly coupled structures can be driven by a single rf power system, through single rf drive loop, at a single rf frequency. The relative phase and relative amplitude of the fields in the two structures are locked by the resonant coupler. Such systems require no control of phase of the rf power. By designing the rf power system to track the resonant frequency of the combined structures, the control of the resonant frequencies of the two structures is greatly simplified. A simple, compact, resonant coupler, based on a quarter-wave-stub, will be described. Models of this resonant couple have been tuned and adjusted, and are scheduled to be tested at operating powers in the early fall (2008). |
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THP088 | High Power 325 MHz Vector Modulators for the Fermilab High Intensity Neutrino Source (HINS) | cavity, solenoid, feedback, klystron | 996 |
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One of the goals of the low energy 60 MeV section of the Fermilab HINS H- linac is to demonstrate that a total of 40 rf cavities can be powered by a single 2.5 MW, 325 MHz klystron. This requires individual vector modulators at the input of each rf cavity to independently adjust the amplitude and phase of the rf input signal during the 3.5 ms rf pulse. Two versions of vector modulators have been developed; a 500 kW device for the RFQ and a 75 kW modulator for the remaining rf cavities. High power test results showing the vector modulator phase and amplitude responses will be presented. |
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THP098 | RF Vector Control for Efficient Fan-Out Power Distribution | cavity, controls, impedance, coupling | 1018 |
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Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE. |
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THP099 | Spallation Neutron Source Superconducting Linac Klystron to Cavity Mismatch Effects and Compensation | klystron, cavity, LLRF, cathode | 1021 |
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Funding: Oak Ridge National Laboratory, P.O. Box 2008 Oak Ridge, Tennessee 37831-6285 managed by UT-BATTELLE, LLC for the U.S. Department of Energy Under Contract DE-AC05-00OR22725 |
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THP102 | Evaluation of Fast ADCs for Direct Sampling RF Field Detection for the European XFEL and ILC | cavity, monitoring, LLRF, feedback | 1030 |
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For the LLRF system of superconducting linacs, precision measurements of the rf phase and amplitude are critical for the achievable field stability. In this paper, a fast ADC (ADS5474) has been evaluated for the measurement of a 1.3 GHz rf signal directly without frequency down conversion. The ADC clock frequency is synchronized with the rf frequency and chosen for non-IQ demodulation. In the laboratory, the Signal to Noise Ratio (SNR) of the ADC was studied for different clock and rf input levels, and the temperature sensitivity of the ADC has been determined. A full bandwidth phase jitter of 0.2 degree (RMS) and amplitude jitter of 0.32% (RMS) was measured. For field control of superconducting cavities with a closed loop bandwidth up to 100 KHz, one can expect to achieve a phase stability close to 0.01 degree. The main limitation will be the jitter of the external clock. We present a measurements at the cavities at FLASH and compare the result with the existing system. |
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THP105 | LLRF Control System of the J-PARC LINAC | cavity, controls, feedback, beam-loading | 1039 |
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At the J-PARC 181 MeV proton linac, the rf sources consist of 4 solid-state amplifiers and 20 klystrons with operation frequency of 324 MHz. The rf fields of each rf source are controlled by a digital feedback system installed in a compact PCI (cPCI). A very good stability of the accelerating fields has been successfully achieved about ±0.2% in amplitude and ±0.2 degree in phase, much better than the requirements of ±1% in amplitude and ±1 degree in phase. Besides, the tuning of each accelerator cavity including 3 DTL and 15 SDTL is also controlled by this LLRF system through a cavity tuner. We pre-defined the cavity resonance states with the tuner adjusted to obtain a flat phase during the cavity field decay. The cavity auto-tuning is well controlled to keep the phase of rf fields within ±1 degree. Furthermore, from the amplitude waveform during the cavity field decay, the Q-value of each cavity is calculated in real-time and displayed in the PLC TP of the LLRF control system. |
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THP110 | Pulse-by-Pulse Switching of Beam Loading Compensation in J-PARC Linac RF Control | controls, beam-loading, LLRF, cavity | 1054 |
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For the J-PARC linac low level rf system, in order to compensate beam-loading change by pulses in the operation of 25 Hz repetition, a function that switches the feed-forward control parameters in every pulse were installed into the digital accelerating-field control system. The linac provides a 50 mA peak current proton beam to a 3 GeV rapid-cycling synchrotron (RCS). Then the RCS distributes the 3-GeV beam into a following 50 GeV synchrotron (main ring, MR) and the Materials and Life Science Facility (MLF), which is one of the experimental facilities in the J-PARC. The 500-us long macro pulses from the ion source of the linac should be chopped into medium pulses for injection into the RCS. The duty (width or repetition) of the medium pulse depends on which facility the RCS provides the beam to the MR or MLF. Therefore the beam loading compensation needs to be corrected for the change of the medium pulse duty in the 25 Hz operation. |
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THP114 | New LLRF System for Fermilab 201.25 MHz Linac | LLRF, controls, cavity, feedback | 1066 |
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The Fermilab Proton Plan, tasked to increase the intensity and reliability of the Proton Source, has identified the Low Level RF (LLRF) system as the critical component to be upgraded in the Linac. The current 201.25 MHz Drift Tube Linac LLRF system was designed and built over 35 years ago and does not meet the higher beam quality requirements under the new Proton Plan. A new VXI based LLRF system has been designed to improve cavity vector regulation and reduce beam losses. The upgrade includes an adaptive feedforward system for beam loading compensation, a new phase feedback system, and a digital phase comparator for cavity tuning. The new LLRF system is phase locked to a temperature stabilized 805 MHz reference line, currently used as frequency standard in the higher energy accelerating section of the Linac. This paper will address the current status of the project, present the advancements in both amplitude and phase stability over the old LLRF system, and discuss commissioning plans. |
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THP115 | Optimizing Cavity Gradients in Pulsed Linacs Using the Cavity Transient Response | cavity, controls, beam-loading, klystron | 1069 |
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Pulsed Linac accelerators are being designed powering a string of cavities from one klystron. A typical low level rf control loop controls the amplitude and the phase of the klystron's rf power; however, the loop cannot dynamically control individual cavity amplitude and phases. The problem is further complicated by the need to obtain the maximum possible acceleration from the rf unit. Proton Linacs (HINS, ProjectX) add extra complexity. A rf unit may need cavities operating at different synchronous phases. Particles travel cavities at increasing velocities, which implies different beam loading conditions. For pulsed proton Linacs amplitude and phase stability are crucial for beam stability. The usual steady state approach determines optimality conditions for minimum generator power as a function of rf parameters. This approach does not provide constant amplitude and phases when the beam is on. In this paper we propose a novel theory using the cavity transient response. The transient response allows setting flat cavity gradients (A and phi) for each cavity in the unit. The optimized rf parameters for the transient response are the cavity coupling parameter and cavity tuning angle. |
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THP117 | Design and Evaluation of the Low-Level RF Electronics for the ILC Main LINAC | cavity, LLRF, low-level-rf, controls | 1075 |
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Funding: Work supported by Fermi Research Alliance LLC. Under DE-AC02- 07CH11359 with the U.S. DOE |
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THP120 | Concept Design Studies of the REX-ISOLDE Cryomodules at CERN | vacuum, cavity, cryomodule, solenoid | 1081 |
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The High Intensity and Energy (HIE) proposal plans a major upgrade of the existing ISOLDE and REX-ISOLDE facilities at CERN, with the objective of substantially increasing the energy and the intensity of the delivered radioactive ion beams. In the frame of this upgrade activity, a superconducting linac, based on Nb sputtered Quarter Wave Resonators (QWRs) is proposed to be installed downstream of the present normal conducting machine. The present design of the accelerator lattice features housing of five high-beta cavities (β=10.6%) and a superconducting solenoid in a common cryomodule. In most of the existing low-energy heavy-ion installations worldwide, insulation and beam vacuum are in common, with the risk of cavity surface contamination in case of accidental leak to the cryostat vessel. Following a concept study, we report in this paper on three design options, namely cryomodules with common vacuum, with separate or with hybrid vacuum systems (the latter having a low conductance between insulation and beam vacuum) and compare them in terms of technical complexity, performance, reliability and maintainability. |
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THP122 | Overview of the First Five Refurbished CEBAF Cryomodules | cryomodule, cavity, vacuum, electron | 1084 |
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Funding: Authored by JSA, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 |
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FR102 | Commissioning of the LCLS Linac | emittance, laser, FEL, electron | 1095 |
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Funding: This work was supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515 |
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FR105 | Billion Particle Linac Simulations for Future Light Sources | electron, simulation, space-charge, FEL | 1110 |
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Funding: This work was supported by the Office of Science, U.S. Department of Energy under DOE contract number DE-AC03-76SF00098. |
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FR201 | The IFMIF 5 MW Linacs | rfq, target, emittance, simulation | 1114 |
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The International Fusion Materials Irradiation Facility (IFMIF) is based on two high power cw accelerator drivers, each delivering a 125 mA deuteron beam at 40 MeV to the common lithium target. The present design of the 5 MW IFMIF Linacs, as well as the description of the prototype accelerator to be built in Japan are presented: the injector including the 140 mA ion source and the magnetic focusing LEBT, the RFQ for the bunching and acceleration to 5 MeV, the MEBT for the proper injection into the Drift-Tube-Linac where the beam is accelerated to the final energy of 40 MeV. Recently, the Alvarez type DTL was replaced by a superconducting Half-Wave Resonator Linac to benefit from the advantages of the SRF technology, in particular the rf power reduction, plug power saving, ability to accelerate high intensity cw beams with high flexibility and reliability. Last, a HEBT section transports and tailors the beam as a flat rectangular profile on the flowing Lithium target. The design and technology choices will be validated during the EVEDA phase, which includes the construction of one full-intensity deuteron linac, but at a lower energy (9 MeV) at Rokkasho Mura in Japan. |
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FR202 | Linacs for Future Muon Facilities | optics, focusing, acceleration, cavity | 1119 |
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Funding: Supported in part by DOE STTR grant DE-FG02-05ER86253 |
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FR203 | Neutrons and Photons: Probes of Condensed Matter | neutron, synchrotron, synchrotron-radiation, instrumentation | 1124 |
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Synchrotron X-rays and neutrons provide unique microscopic information on the structures and dynamics of condensed matter. These probes are essential tools for biologists, chemists, physicists and materials scientists and have become increasingly important in a remarkably wide range of disciplines, from palaeontology to medicine. The electron storage rings producing synchrotron radiation, and fission reactor or spallation neutron sources, are usually situated at major national or international laboratories. Such central research facilities are exemplified by the two international laboratories in Grenoble, the European Synchrotron Radiation Facility and the Institut Laue-Langevin. After a discussion of the sources used to produce synchrotron radiation and neutron beams, some of the instrumentation and methods used in the investigation of materials will be described, with illustrative examples of recent research. Finally, some major X-ray and neutron sources under construction or at the planning stage will be described, including several where linac technology plays an important role (e.g. the XFEL at DESY and the SNS at ORNL). |
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