Paper | Title | Other Keywords | Page |
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MO204 | The Injector Systems of the FAIR Project | ion, linac, 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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MO302 | Overview of Recent RFQ Projects | rfq, ion, linac, 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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MOP029 | Beam Dynamics Studies for the SCREX-ISOLDE Linac at CERN | cryomodule, linac, 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, linac, simulation | 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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MOP031 | Estimates of Energy Fluence at the Focal Plane in Beams Undergoing Neutralized Drift Compression | solenoid, target, bunching, induction | 133 |
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Funding: Work performed under the auspices of the U.S. Department of Energy under contract DE-AC52-07NA27344 at LLNL, and University of California contract DE-AC03-76SF00098 at LBNL. |
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MOP032 | Upgrade of the Unilac High Current Injector RFQ | rfq, simulation, ion, focusing | 136 |
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Funding: Work supported by the European Community INTAS Project Ref. no. 06-1000012-8782. |
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MOP033 | The New EBIS RFQ for BNL | rfq, ion, linac, alignment | 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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MOP036 | The IFMIF-EVEDA RFQ: Beam Dynamics Design | rfq, focusing, space-charge, beam-losses | 145 |
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The IFMIF-EVEDA (Engineering Validation and Engineering Design Activities) project foresees the construction of a high intensity deuteron accelerator up to 9 MeV, with the characteristics required for the actual IFMIF facility. The linac will be installed in Rokkasho, and INFN is in charge of the construction of a 5 MeV, 125 mA, deuteron RFQ operating at 175 MHz. In this article the beam dynamics design of this challenging RFQ is described, namely the design, the main outcomes in terms of beam particles physics, and finally the study of mechanical and rf field error tolerances. The RFQ design method has been aimed to the optimization of the voltage and R0 law along the RFQ, the accurate tuning of the maximum surface field and the enlargement of the acceptance in the final part of the structure. As a result this RFQ is characterized by a length shorter than in all previous design, very low losses (especially at higher energy) and small rf power dissipation. |
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MOP040 | The Radiofrequency Quadrupole Accelerator for the Linac4 | rfq, linac, cavity, 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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MOP041 | The Fabrication and Initial Testing of the HINS RFQ | rfq, simulation, vacuum, quadrupole | 160 |
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Fermilab is designing and building the HINS front-end test facility. The HINS proton linear accelerator consists of a normal-conducting and a superconducting section. The normal-conducting (warm) section is composed of an ion source, a 2.5 MeV radio frequency quadrupole (RFQ), a medium energy beam transport, and 16 normal-conducting crossbar H-type cavities that accelerate the beam to 10 MeV. Production of 325 MHz 4-vane RFQ is recently completed. This paper presents the design concepts for this RFQ, the mechanical design and tuning results. Issues that arose during manufacturing of the RFQ will be discussed and specific corrective modifications will be explained. The preliminary results of initial testing of RFQ at the test facility will be presented and comparisons with the former simulations will also be discussed. |
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MOP046 | Commissioning of the New GSI-Charge State Separator System for High Current Heavy Ion Beams | ion, space-charge, dipole, heavy-ion | 175 |
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A dedicated charge separator system is now installed in the transfer line to the GSI-synchrotron SIS18. In former times charge separation was performed with a single 11 degree dipole magnet after a 25 m beam transport section. This was not adequate to meet the requirements during high current operation for FAIR: it only allows for charge state separation of low intensity and low emittance beams. With the new compact charge separator system emittance blow up and unwanted beam losses for high intensity beam operation will be avoided. Additionally a new beam diagnostics test bench is integrated. With this the beam parameters (ion current, beam profile, beam position, transversal emittance, bunch structure and beam energy) for the injection into the SIS18 can be measured in parallel to the routine operation in the transfer line. Results of the commissioning with high intensity argon beams as well as with an uranium beam will be reported. |
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MOP052 | Re-phasing of the ISAC Superconducting Linac with Computed Values | linac, cavity, 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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MOP057 | Linac Front-End Upgrade at the Cancer Therapy Facility HIT | rfq, linac, solenoid, ion | 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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MOP066 | Status of MICE: the International Muon Ionization Cooling Experiment | cavity, proton, solenoid, coupling | 229 |
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Funding: This work was partially supported by the Office of Science, U. S. Department of Energy, under Contract No. DE-AC02-05CH11231. |
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MOP068 | Trains of Sub-Picosecond Electron Bunches for High-Gradient Plasma Wakefield Acceleration | plasma, wakefield, electron, simulation | 235 |
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Funding: Work Supported by US Department of Energy *P. Muggli et al., to appear in Phys. Rev. Lett. (2008). |
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MOP072 | Beam Dynamics Simulation of the Low Energy Beam Transport Line for IFMIF/EVEDA | simulation, rfq, space-charge, injection | 242 |
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The purpose of the IFMIF-EVEDA (International Fusion Materials Irradiation Facility-Engineering Validation and Engineering Design Activities) demonstrator is to accelerate a 125 mA cw deuteron beam up to 9 MeV. Therefore, the project requires that the ion source and the low energy beam transport (LEBT) line deliver a 140 mA cw deuteron beam with an energy of 100 keV and an emittance of 0.25 π .mm.mrad (rms normalized) at the entrance of the RFQ. The deuteron beam is extracted from a 2.45 GHz ECR source based on the SILHI design*. A LEBT with a two solenoids focusing system is foreseen to transport and adapt the beam for the RFQ injection. In order to validate the LEBT design, intensive beam dynamics simulations have been carried out using a parallel implementation of a particle-in-cell 3D code which takes into account the space charge compensation of the beam induced by the ionisation of the residual gas. The simulations results (in particular from the emittance growth point of view) performed under several conditions of gas species or gas pressure in the beam line are presented. *R. Gobin et al, Rev. Sci. Instrum. 79, 02B303 (2008). |
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MOP073 | Parameter Design and Beam Dynamics Simulations for the IFMIF-EVEDA Accelerators | linac, 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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MOP074 | Beam Dynamics Simulations of Sub-ps Electron Bunch Produced in a Photo-Injector | simulation, electron, laser, gun | 248 |
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A growing number of experiments require low emittance ultra-short electron bunches in the 100 fs range (rms value) for the production of coherent light or the injection in plasma for laser-plasma acceleration. Especially in the last case it is highly desirable to have a compact accelerator; hence a strong experimental activity is carried out to get such a beam directly from a photo-injector. We have performed beam dynamic simulations using the PARMELA code to study the performances of the alphaX photo-injector installed in the University of Strathclyde in UK. This rf gun is aimed to produce electron bunches of 100 pC bunch charge, 100 fs bunch length and 1 mmmrad transverse emittance. We will show the results of systematic parametric studies as a function of charge and laser pulse duration as well as the natural evolution of the beam phase space as a function of the distance from the photo-cathode. |
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MOP075 | Benchmarking of Measurement and Simulation of Transverse RMS-Emittance Growth Along an Alvarez DTL | DTL, simulation, quadrupole, linac | 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 | linac, target, rfq, 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 | linac, 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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MOP083 | Analysis of Input Coupler Asymmetry Influence on Beam Dynamics in Accelerators with Superconducting Cavities | cavity, electron, superconducting-cavity, simulation | 269 |
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Analysis of input coupler asymmetry influence on beam dynamics in superconducting cavities of Energy Recovery Linac (ERL) injector is presented. Both coaxial and waveguide, single and twin input couplers were analyzed. Using computer simulation electromagnetic fields distribution in accelerating cavity was obtained and recalculated to the transverse-kick to the bunch passing the coupler. Also calculation of external coupling was done. RTMTRACE code was adapted for particle beams dynamic simulation. Acceptable transverse emittance growth was achieved for twin-coaxial (4%) and waveguide (5%) input coupler designs. |
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MOP086 | End to End Beam Dynamics and RF Error Studies for Linac4 | linac, DTL, 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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MOP088 | Particle Dynamics Calculations and Emittance Measurements at the FETS | rfq, simulation, ion, ion-source | 281 |
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In order to contribute to the development of high power proton accelerators in the MW range, to prepare the way for an ISIS upgrade and to contribute to the UK design effort on neutrino factories, a front end test stand (FETS) is being constructed at the Rutherford Appleton Laboratory (RAL) in the UK. The aim of the FETS is to demonstrate the production of a 60 mA, 2 ms, 50 pps chopped beam at 3 MeV with sufficient beam quality. The results of numerical simulations of the particle dynamics from the charge separation dipole behind the ion source to the end of the MEBT will be presented. Previous measurements showed that the emittance of the beam delivered by the ion source exceeded our expectations by more than a factor of 3. Since then various changes in the beam extraction/post accelerator region reduced the beam emittance by a factor of 2. Simulations of the particle dynamics in the FETS based on distributions gained from recent measurements of the transversal beam emittance behind the ion source will be presented and the results for different input distributions discussed. |
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MOP089 | Beam Dynamics and Wake-field Simulations for High Gradient ILC Linacs | cavity, simulation, linac, 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 | linac, rfq, simulation, 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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MOP093 | Study of IBS Effects for High-Brightness Linac Beams | linac, scattering, 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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MOP101 | Simulation of Emittance Growth Using the UAL String Space Charge Model | simulation, space-charge, electron, synchrotron | 308 |
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Evolution of short intense electron bunches passing through bunch-compressing beamlines is simulated using the UAL (Unified Accelerator Libraries) string space charge formulation. Excellent agreement is obtained with results obtained experimentally at CTF-II, the CERN "Compact Linear Collider'' test facility. The 40 MeV energy of these data is low enough for Coulomb and Biot-Savart forces to be important and high enough for coherent synchrotron radiation and centrifugal space charge forces to be important. UAL results are also compared with CSRtrack results for emittance growth in a 40 MeV 'standard' chicane. Vertical space charge forces are found to be important in this (low energy) case. |
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MOP104 | Parallel 3D Finite Element Particle-In-Cell Code for High-Fidelity RF Gun Simulations | simulation, gun, wakefield, space-charge | 317 |
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Funding: Work supported by DOE contract DE-AC02-76SF00515. |
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MOP105 | Beam Dynamics and Wake-field Simulations for the CLIC Main Linacs | wakefield, cavity, damping, linac | 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, linac, 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 | linac, 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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TU104 | Laser Acceleration of Quasi-Monoenergetic MeV-GeV Ion Beams | laser, acceleration, ion, target | 358 |
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Laser interactions with thin solid targets can produce sheath fields of tens of TV/m, which have been used to accelerate ions to several MeV with ps pulse lengths, high currents, and low transverse emittance. While previous results have had 100% energy spread, recent experiments using foils coated with a few monolayers have produced quasi-monoenergetic beams with 17% energy spread near 3 MeV. Such beams may be of interest as injectors or sources. Simulations show the potential for acceleration to hundreds of MeV or GeV energies using very thin foils. |
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TU301 | Positron Beams Propagation in Plasma Wakefield Accelerators | plasma, positron, electron, laser | 374 |
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Funding: Work Supported by US Department of Energy *I. Blumenfeld et al., Nature 445, 741-744 (15 February 2007). |
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TUP016 | Status of an Automatic Beam Steering for the CLIC Test Facility 3 | linac, quadrupole, lattice, 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, linac, simulation, target | 428 |
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Funding: The present work is supported by the STCU project #P233 |
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TUP019 | Injector of Intense Electron Beam | electron, simulation, bunching, cavity | 431 |
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The results of beam dynamic simulation in an S-band injector that can be used for creation of the powerful electron linac are presented in the report. The injector consists of a diode electron gun with beam current of up to 2 A at energy of electrons of 25 keV, the klystron type prebuncher and the three cavity buncher. In the buncher, due to the special choice of eigen frequencies of resonators, maximal amplitude of the field on the axis of resonators exponentially increase from the first (downstream of the beam) resonator to the last resonator. It allows effective bunching the intensive electron beam and accelerating it to relativistic velocities. For providing of low transversal beam emittance the injector is placed in the external magnetic field. The injector provides more than 1 A of beam current at particle energies of about 1 MeV. Attention is paid to research of transients and stability of injector work. |
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TUP023 | Optimization of Lattice for an ERL Upgrade to the Advanced Photon Source | brightness, radiation, lattice, optics | 441 |
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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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TUP024 | Growth of Density Modulations in an Energy Recovery Linac Light Source due to Coherent Synchrotron Radiation and Longitudinal Space Charge | lattice, linac, simulation, 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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TUP026 | Exploring Benefits of Using RF Deflection for Short X-Ray Pulse Generation for an Energy-Recovery Linac Upgrade to the Advanced Photon Source | undulator, photon, cavity, radiation | 447 |
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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. *A. Zholents, et al., Nucl. Instr. and Meth. A 425 (1999) 385. |
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TUP028 | Status of High Current R&D Energy Recovery Linac at Brookhaven National Laboratory | electron, cavity, gun, SRF | 453 |
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Funding: Work performed under contract No. DE-AC02-98CH10886 with the auspices of the DoE of United States. |
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TUP031 | Normal Conducting Options for the UK's New Light Source Project | linac, klystron, 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, damping, HOM, linac | 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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TUP035 | New Experimental Results from PITZ | gun, cathode, cavity, laser | 474 |
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Funding: This work was partly supported by the European Community, contracts RII3-CT-2004-506008 and 011935, and by the 'Impuls- und Vernetzungsfonds' of the Helmholtz Association, contract number VH-FZ-005. * L. Staykov et al., "Measurements of the Projected Normalized Transverse Emittance at PITZ", Proceedings of the FEL 2007, Novosibirsk, Russia, August 2007. |
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TUP040 | Linear Accelerator for the PSI-XFEL FEL3 Beamline | linac, FEL, 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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TUP042 | High Repetition Rate Electron Injectors for FEL Based Next Generation Light Sources | gun, cavity, SRF, simulation | 489 |
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Several laboratories concentrate their efforts on development of high repetition rate FEL based next generation light sources. One particular concept under development at STFC Daresbury Laboratory specifies high brightness electron bunches with a charge of 0.2-1 nC which arrive with a frequency up to 1 MHz. As emittance of the bunches should not exceed 1 um, traditional high repetition rate thermionic injectors, similar to the ones used at high micropulse repetition rate FELs like ELBE or FELIX, may not be used. We consider three options of high repetition rate injectors based on photocathode guns - a high voltage dc gun, a one and half cell superconducting rf gun and a normal conducting VHF gun, recently proposed at LBNL. We consider practical injector schemes for all three guns and provide the results of beam dynamic simulations. We also discuss the photocathodes which may be used in each gun, as this critical component defines achievable beam parameters and operational efficiency of the injectors. |
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TUP045 | Generation of Femtosecond Bunch Trains Using a Longitudinal-to-Transverse Phase Space Exchange Technique | dipole, simulation, cavity, electron | 498 |
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Funding: Work supported by the Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. DOE and by Northern Illinois University under Contract No. DE-FG02-08ER41532 with the U.S. DOE *P. Emma, Z. Huang, K.-J. Kim, and P. Piot, Phys. Rev. ST Accel. Beams 9, 100702 (2006). |
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TUP046 | Linac Design for an Array of Soft X-Ray Free Electron Lasers | linac, electron, FEL, 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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TUP053 | Experimental Characterization and Optimization of High-brightness Electron Beam at the NSLS SDL | laser, injection, solenoid, electron | 521 |
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The Source Development Laboratory (SDL) at the National Synchrotron Light Source (NSLS) is a laser linac facility dedicated for laser seeded FEL and beam physics R&D. The SDL consists of a RF synchronized Ti:sapphire laser, a BNL photocathode RF gun, a four-magnet chicane bunch compressor, and a 300 MeV linac. To further improve the performance of the laser seeded FEL at the NSLS SDL, we have carried out a systematic experimental characterization of the high-brightness electron beam generated by the photocathode RF gun. We will present the experimental studies of both transverse and longitudinal emittance of electron beam as a function of RF gun phase and solenoid magnet for electron beam charge ranging from 350 pC to 1 nC and their influences on FEL output. |
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TUP073 | Tailoring the Emittance of a Charged Particle Beam with a Tunnel Emittance Meter | ion, brilliance, ion-source, electron | 561 |
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Based on the 'tunnel' emittance used for electron focusing, a similar procedure with two pairs of slits with variable widths is proposed to evaluate fractional emittances and brilliances for ion beams. The measurement starts with closing both slits (one after the other), until a certain fraction of the beam current is cut out. The emittance and brilliance then is well defined for the passing beam part. Formulae are given for the emittance as well as for the brilliance in dependence of the slit width and current. This emittance measurement is free from the background subtraction problem found in the classical density measurement of phase space(s). The functions for the decrease of the emittance and for the increase of the brilliance in dependence of the transmitted beam current provide a figure of merit for the quality of the investigated beam. The device at the same time is also an adjustable emittance filter for the passing beam. At the expense of current the emittance and/or brilliance of a beam can be tailored to any value, which is available by the beam quality. |
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TUP074 | Commissioning of the HITRAP Decelerator Using a Single-Shot Pepper Pot Emittance Meter | ion, rfq, linac, 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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TUP083 | Diagnostics and Measurement Strategy for the CERN Linac 4 | linac, diagnostics, DTL, 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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TUP084 | Emittance Measurement Instrument for a High Brilliance H- Ion Beam | ion, laser, diagnostics, rfq | 594 |
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Funding: Work supported by EU/FP6/CARE (HIPPI) RII3-CT-2003-506395 |
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TUP085 | Four-Dimensional Emittance Meter for DC Ion Beams Extracted from an ECR Ion Source | ion, ion-source, ECR, extraction | 597 |
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Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under contract number DE-AC02-06CH11357. |
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TUP086 | Initial Commissioning of a Dual-Sweep Streak Camera on the A0 Photoinjector | laser, cavity, electron, optics | 600 |
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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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TUP093 | Activities on High Brightness Photo-injectors at the Frascati Laboratories, Italy | FEL, linac, 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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TUP094 | Development of a Photocathode RF Gun for an L-Band Electron Linac | cavity, electron, gun, cathode | 621 |
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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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TUP097 | Measurements and Modeling at the PSI-XFEL 500 kV Low-Emittance Electron Source | cathode, electron, simulation, laser | 630 |
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Paul Scherrer Institute (PSI) is presently developing a low emittance electron source for the PSI-XFEL project. The electron gun consists of an adjustable diode configuration subject to pulses of 250 ns (FWHM) with amplitude up to 500 kV from an air-core transformer- based high-voltage pulser. The facility allows high gradient tests with different cathode configurations and emission processes (field emission and photo emission). In the first stage, the beamline is only made up of focussing solenoids followed by an emittance monitor. Selected beam characterization measurements, from photo-cathode operation driven by a 266 nm UV laser system delivering 4 uJ energy during 6.5 ps (FWHM), are presented and compared to the results of 3D particle tracking simulations. |
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TUP099 | Design and Optimization of an S-Band Photoinjector | gun, cavity, solenoid, laser | 636 |
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Many X-ray Free Electron Laser (XFEL) projects are under construction or are being proposed. A photoinjector with low transverse emittance is one of the key elements for successful XFEL operation. For the last two decades, photoinjectors have been developed to reach the XFEL requirement, typically with a normalised emittance of 1 mm mrad for a 1 nC bunch and high peak current. Here, we make a further numerical optimization of an S-band photoinjector to achieve 0.5 mm mrad for 1 nC bunch in a structure that should permit high repetition rates to be achieved. Optimizations for alternative operation conditions with lower charge and lower emittance are also shown. |
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TUP100 | The Optimization of a DC Injector for the Energy Recovery Linac Upgrade to APS | laser, gun, linac, 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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TUP101 | Photocathode R&D Program at LBNL | electron, photon, gun, cathode | 642 |
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Funding: US Deparment of Energy |
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TUP103 | Analysis of Halo Formation in a DC Photoinjector | cathode, electron, space-charge, laser | 645 |
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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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TUP105 | Simulation of the Upgraded Photoinjector for the 10 kW JLAB IR-FEL | laser, simulation, cavity, FEL | 649 |
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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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TUP107 | Longitudinal Beam Diagnostics for the ILC Injectors and Bunch Compressors | diagnostics, luminosity, wakefield, bunching | 655 |
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Funding: Work supported by US. Department of Energy, under Contract No. DE-FG02-06ER41435 with Northern Illinois University. |
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TUP110 | Modeling of a Low Frequency SRF Electron Gun for the Wisconsin FEL | gun, cavity, cathode, FEL | 658 |
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Funding: This work is supported by the University of Wisconsin-Madison and MIT, and by the US NSF under award No. DMR-0537588 * O.J. Luiten, et al., Phys. Rev. Lett., 93, 094802-1 (2004) |
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TUP111 | Longitudinal Bunch Lengthening Compensation in a High Charge RF Photoinjector | gun, booster, electron, solenoid | 661 |
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Funding: Work supported by DOE contract DE-AC02-76SF00515 |
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TUP112 | Laser Timing Jitter Measurements at the Fermilab A0 Photoinjector | laser, cavity, electron, linac | 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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TUP113 | Emittance Exchange at the Fermilab A0 Photoinjector | cavity, optics, dipole, electron | 667 |
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Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy. |
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TUP117 | Development of Ultra-Low Emittance Injector for Future X-Ray FEL Oscillator | linac, 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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TUP118 | Extraction From ECR and Recombination of Multiple-Charge State Heavy-Ion Beams in LEBT | ion, ECR, ion-source, acceleration | 679 |
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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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WE101 | Energy Recovered Linacs | electron, linac, 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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WE104 | First Tests of the Cornell University ERL Injector | cavity, laser, gun, cathode | 699 |
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Funding: Work supported by the National Science Foundation under contract PHY 0131508 |
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TH303 | Towards a Model Driven Accelerator with Petascale Computing | linac, simulation, beam-losses, rfq | 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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THP027 | Welding Helium Vessels to the 3.9 GHz Superconducting Third Harmonic Cavities | cavity, electron, monitoring, cryomodule | 842 |
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Funding: This work was supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. |
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THP066 | Breakdown in Pressurized RF Cavities | cavity, electron, simulation, vacuum | 945 |
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The performance of many particle accelerators is limited by the maximum electric gradient that can be realized in rf cavities. Recent studies have shown that high gradients can be achieved quickly in 805 MHz cavities pressurized with dense hydrogen gas, because the gas can suppress, or essentially eliminate, dark currents and multipacting. In this project, two new test cells operating at 500 MHz and 1.3 GHz will be built and tested, and the high pressure technique will be used to suppress the vacuum effects of evacuated rf cavities, so that the role of metallic surfaces in rf cavity breakdown can be isolated and studied as a function of external magnetic field, frequency, and surface preparation. Previous studies have indicated that the breakdown probability is proportional to a high power of the surface electromagnetic field, in accordance with the Fowler-Nordheim description of electron emission from a cold cathode. The experiments will be compared with computer simulations of the rf breakdown process. |
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THP069 | Design and Test of the Triple-Harmonic Buncher for the NSCL Reaccelerator | cavity, rfq, linac, 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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THP075 | X-Band Traveling Wave RF Deflector Structures | impedance, kicker, factory, electron | 966 |
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Funding: Work supported by U.S. Department of Energy, contract DE-AC02-76SF00515 (SLAC) |
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FR102 | Commissioning of the LCLS Linac | laser, linac, 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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FR201 | The IFMIF 5 MW Linacs | rfq, linac, target, 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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