Paper | Title | Other Keywords | Page |
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MO102 | The European XFEL SC Linac Project | linac, FEL, undulator, 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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MOP027 | Heavy Ion Injector for NICA/MPD Project | ion, rfq, ion-source, linac | 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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MOP043 | Simulation of Multipacting in HINS Accelerating Structures with CST Particle Studio | simulation, cavity, accelerating-gradient, background | 166 |
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Recently high power tests of the room temperature cross-bar H-type resonators (CH resonators) and high gradient tests of a superconducting single spoke resonator (SSR) have been performed under the High Intensity Neutrino Source (HINS) project at Fermilab. The resonators have shown a tendency of having multipacting at various levels of input power and therefore longer processing time. To provide insights for the problem, detailed numerical simulations of multipacting for these resonators have become necessary. New generation of accelerating structures like superconducting spoke resonators and room temperature CH resonators need a full 3D treatment. Simulations and study of multipacting in the resonators have been carried out using CST Particle Studio. The problematic regions and power levels have been identified for both types of resonators. This presentation will give the result of simulations and comparison with experimental data. |
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MOP063 | High-Power Lithium Target for Accelerator-Based BNCT | target, linac, neutron, 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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MOP064 | Bent Solenoid Tuning Simulations for the COMET Beamline | solenoid, simulation, target, dipole | 226 |
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The COMET experiment beamline uses bent solenoids for the muon transport and the spectrometer used to analyse the decay electrons from stopped muons. The bent solenoid includes not just a solenoid field but also a vertical dipole field. It is therefore important to have the ability to tune the field distribution. However, since the field distribution is mainly determined by the geometry it is difficult to adjust once the solenoids have been constructed. A cost effective method to provide tuning capability of the field distribution of the bent solenoids is proposed and the results of simulations presented. |
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MOP067 | High Gradient Excitation and RF Power Generation Using Dielectric Loaded Wakefield Structures | wakefield, gun, klystron, laser | 232 |
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Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-06CH11357. |
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MOP068 | Trains of Sub-Picosecond Electron Bunches for High-Gradient Plasma Wakefield Acceleration | plasma, wakefield, emittance, 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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MOP074 | Beam Dynamics Simulations of Sub-ps Electron Bunch Produced in a Photo-Injector | emittance, simulation, 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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MOP076 | Integration of Fringe Field Alpha Magnets into the V-Code Beam Dynamics Simulation Tool | simulation, multipole, dipole, focusing | 254 |
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Funding: This work was partially funded by DESY Hamburg and DFG (SFB 634). |
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MOP082 | Multipacting Simulation in RF Structures | simulation, multipactoring, cavity, linac | 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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MOP083 | Analysis of Input Coupler Asymmetry Influence on Beam Dynamics in Accelerators with Superconducting Cavities | emittance, cavity, 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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MOP087 | Status of Longitudinal Beam Dynamics Studies in CTF3 | simulation, wakefield, space-charge, cavity | 278 |
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The aim of the CLIC Test Facility CTF3, built at CERN by an international collaboration, is to address the main feasibility issues of the CLIC electron-positron linear collider technology by 2010. One key-issue studied in CTF3 is the generation of the very high current drive beam, used in CLIC as the rf power source. It is particularly important to simulate and control the drive beam longitudinal dynamics in the drive beam generation complex, since it directly affects the efficiency and stability of the rf power production process. In this paper we describe the ongoing effort in modelling the longitudinal evolution of the CTF3 drive beam and compare the simulations with experimental results. |
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MOP092 | Monte Carlo Simulation of Touschek Effects in a Linac Beam | scattering, simulation, beam-losses, linac | 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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MOP098 | The Open Architecture Software Integration System (OASIS) for Creating PBO Lab Modules | optics, target | 302 |
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A specialized software package has been developed that enables the rapid implementation of custom beam optics modules that run in the Particle Beam Optics Laboratory (PBO Lab). PBO Lab is a commercially available software application that supports a suite of accelerator codes for design, operations, and personnel education. The intuitive and easy-to-use graphic user interface (GUI) is largely responsible for the popularity of PBO Lab. The Open Architecture Software Integration System, or OASIS, builds upon the capability of PBO Lab to host a suite of different codes, and provides an innovative framework that allows users to readily integrate their own optics programs into PBO Lab. The OASIS GUI can be used to readily create new PBO Lab modules without writing or compiling any source code. OASIS has been used to develop several new modules for PBO Lab. This paper presents a summary of the OASIS framework and describes some of the features used in creating the new PBO Lab modules for several popular optics codes. |
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MOP101 | Simulation of Emittance Growth Using the UAL String Space Charge Model | simulation, emittance, space-charge, 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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MOP102 | Electron Beam Dynamics in the DARHT-II Linear Induction Accelerator | induction, dipole, focusing, impedance | 311 |
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Funding: Work supported by USDOE under contract DE-AC52-06NA25396 *"Long-pulse beam stability experiments on the DARHT-II linear induction accelerator", Carl Ekdahl, et al., IEEE Trans. Plasma. Sci. Vol. 34, 2006, pp. 460-466. |
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MOP110 | Precise Control of Cooling Water System for Stabilization of 125 MeV Linac at LEBRA | linac, 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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TU301 | Positron Beams Propagation in Plasma Wakefield Accelerators | plasma, positron, emittance, 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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TUP002 | ARIEL and the TRIUMF E-Linac Initiative, a 0.5 MW Electron Linac for Rare Isotope Beam Production | linac, cavity, TRIUMF, 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, linac, high-voltage, cavity | 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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TUP007 | The Power and Polarisation Upgrade Project at the S-DALINAC Injector | cavity, cathode, polarization, vacuum | 398 |
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Funding: Work supported by the DFG through SFB 634 |
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TUP008 | Recent Changes to the e- / e+ Injector (Linac II) at DESY | linac, target, positron, gun | 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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TUP010 | Pulse-to-Pulse Mode Switching of KEKB Injector Linac | target, injection, positron, linac | 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 | linac, 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, linac | 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 | linac, 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 | linac, injection, positron, 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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TUP018 | A 150 MeV Pulse Electron Linac with a 1 mA Average Current | linac, simulation, target, emittance | 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 | simulation, bunching, cavity, emittance | 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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TUP028 | Status of High Current R&D Energy Recovery Linac at Brookhaven National Laboratory | cavity, emittance, 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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TUP029 | Electron Linac Based Coherent Radiation Light Source Project at OPU | radiation, linac, 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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TUP033 | Lattice Studies for the XFEL-Injector | optics, laser, diagnostics, undulator | 468 |
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The XFEL injector building has a length of 74.3 metres and is divided by 2.5 m long concrete shielding wall. The section upstream the shielding wall will have a length of 42.3 m and give place for the gun, accelerating module, 3rd harmonic section, laser heater and the beam diagnostics section. At its end the possibility for the beam dump is foreseen so that the tuning of the beam in the injector would become possible without any impact on the subsequent parts of the XFEL. Each of these components sets certain requirements on beam optics which may compete with each other. Downstream the shielding the beam will be vertically displaced by 2.75 m over the distance of 20 m by means of the so called dogleg - a combination of two four cell arcs (8 cell system). Since the vertical displacement takes place there it is important to optimize cells in such an order that the chromatic effects don't impact the beam quality noticeably. In this paper we describe the solution for the beam optics at the XFEL injector. |
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TUP034 | Status of the 3rd Harmonic Systems for FLASH and XFEL in Summer 2008 | cavity, klystron, linac, controls | 471 |
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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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TUP038 | MIR-FEL with 4.5-Cell Thermionic RF-Gun | FEL, gun, undulator, klystron | 477 |
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An MIR-FEL facility, Kyoto University FEL (KU-FEL), has been developed for applications in "sustainable energy science", such as fundamental studies on high-efficiency solar cells. The KU-FEL, consisting of an S-band thermionic rf gun, a 3 m accelerator tube and a planer undulator, aims to generate 4-13 μmeter tunable FEL. The first lasing was achieved on March, 2008 at 12.4 μmeters by using a beamloading compensation method both in the rf gun and in the accelerator tube. *Furthermore, we introduced detuning to the rf gun and succeeded to generate an electron beam with macropulse duration of 5.1 μseconds, average current of 100 mA and energy spread of 0.5% which led to power saturation in FEL. In the conference, the improvements of the electron beam properties and power saturation of the KU-FEL will be discussed. *H. Ohgaki et al., 'First Lasing at 12 um Mid Infrared Free Electron Laser at Kyoto University', Japanese Journal of Applied Physics, accepted for publication. (2008). |
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TUP039 | Status of the LINAC-800 Construction at JINR | linac, 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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TUP043 | Development of a Beam Loss Monitor System for the LCLS Undulator Beamline | undulator, beam-losses, simulation, radiation | 492 |
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Funding: Work Argonne supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02-06CH11357. |
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TUP045 | Generation of Femtosecond Bunch Trains Using a Longitudinal-to-Transverse Phase Space Exchange Technique | emittance, dipole, simulation, cavity | 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, 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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TUP047 | Manipulating the Two-Stream Instability for Efficient Terahertz Generation | bunching, radiation, coupling, simulation | 504 |
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Particle beams have exhibited a two-stream instability for many decades; this undesirable trait has been well-understood for many years. We propose creating a scheme that uses a beam of electrons with two distinct energies that will develop the two-stream instability as a bunching mechanism. By controlling the beam parameters and seeding them with a low-level rf signal, a gain as high as 2.5 dB per centimeter is predicted. We show the theory behind this concept and recent progress in a developing experiment. |
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TUP049 | The Electron Bunch Initial Energy Profile on a Seeded Free Electron Laser Performance | FEL, undulator, free-electron-laser, laser | 509 |
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Funding: The work of AWC and JW was supported by the US Department of Energy under contract DE-AC02-76SF00515. The work of JB was supported by National Science Foundation Award No. DMR-0537588. |
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TUP050 | Design and Optimization of Electron Bunch Acceleration and Compression | wakefield, linac, 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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TUP051 | Design of Microwave Undulator Cavity | undulator, cavity, radiation, synchrotron | 515 |
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Static magnetic field undulators are capable of producing quasi-monochromatic synchrotron radiation of very high brightness. However, it is not possible to quickly change the properties such as polarization of the radiation in a static undulator. It is possible to construct an undulator using microwaves instead of static magnets where the electron beam is undulated by both electric and magnetic fields of an rf wave. A major advantage with a microwave undulator is that the radiation properties can be changed very quickly. The biggest challenge in developing a microwave undulator is in keeping the rf losses low. We are designing a microwave undulator with the aim of achieving at least a tenth of the flux obtained by the BL13 static magnetic field Elliptical Polarized Undulator in the SPEAR ring. We have considered circular waveguide modes and hybrid HE11 mode in a corrugated waveguide as possible candidates for the microwave undulator. It is found that a corrugated waveguide has the lowest rf losses with a very desirable field profile. It is also possible to use this device for a linac driven FEL. Our analysis of the corrugated waveguide cavity for the rf undulator will be presented. |
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TUP052 | Status of the NPS Free-Electron Laser | FEL, booster, undulator, laser | 518 |
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Funding: This research is supported by the Office of Naval Research and the Joint Technology Office. |
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TUP053 | Experimental Characterization and Optimization of High-brightness Electron Beam at the NSLS SDL | emittance, laser, injection, solenoid | 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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TUP063 | Development of a New Highly Bright X-ray Generator | brightness, radiation, target, synchrotron | 539 |
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A new type of rotating anticathode X-ray generator has been developed, in which the electron beam irradiates the inner surface of a U-shaped anticathode. A high-flux electron beam is focused on the inner surface by optimizing the shape of the bending magnet. In order to minimize the sizes of the X-ray source, the electron beam is focused strongly in a short distance by the bending magnet which is small and is close to the rotating anticathode. The power of the electron beam can be increased to the point at which the irradiated part of the inner surface is melted, because a strong centrifugal force fixes the melted part on the inner surface. We have achieved emission of X-rays 10 times more brilliant than can be attained by a conventional rotating anticathode. The development is still in progress. New results will be reported in detail. |
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TUP064 | Nuclear Reaction Analysis by Using Quasi-Elastic Scattering of Ultra Low Intensity Electron Beams | neutron, target, radiation, scattering | 542 |
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Energetic electron beams higher than several MeV occasionally induce direct nuclear reactions with the target nuclei. These processes are attributed to the quasi-elastic scattering of electrons (e,e') with the target nuclei and similar to the photo-nuclear reactions. These reactions are considered to be useful for the non-destructive analysis of heavy elements such as U and Th. In addition, a two-dimensional analysis is realized only by scanning of electron beam. On the other hand, the huge X-ray burst caused by the bremsstrahlung with the electron pulse bombardment is the most harmful phenomenon for the radiation measurement system. In this study, an ultra low intensity electron beam was used for relieving the problem, which has been developed by modifying an electron linear accelerator. The minimum beam charge about several aC/pulse has been achieved at the present. Consequently, the neutron emitted by Pb(e,e'n)Pb reaction was measured successfully by the use of the low intensity beams. The linearity between the neutron count and the concentration of Pb in the target was verified experimentally. |
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TUP065 | Demonstration of Multi-Pulse X-ray Generation via Laser-Compton Scattering Using Pulsed-Laser Super-Cavity | laser, cavity, photon, linac | 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 | klystron, linac, gun, high-voltage | 548 |
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Funding: This work is supported by KAPRA and POSTECH Physics BK21 Program. |
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TUP068 | Project of a Neutron Source Based on the Sub-Critical Assembly Driven by Electron Linear Accelerator | neutron, target, octupole, shielding | 551 |
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Today accelerator driven subcritical assembly is candidate for the next generation of energy-generating nuclear facility, which could provide safe energy production, burning of transuranium elements and transmutation of radionuclides. Use of the electron beam with particle energy up to 150-200 MeV secures several advantages. Electron linear accelerators are much cheaper compared to hadron accelerators. Homogeneous irradiation of the assembly with neutrons could be provided. NSC KIPT together with ANL develops the project of a neutron source based on the sub-critical assembly driven by electron linear accelerator. Energy of electrons is 100-200 MeV. The target and assembly design is optimized to maximize the neutron source intensity with subcriticality of 0.98. Accelerator on average beam power of 100 kW, with repetition rate up to 300 Hz and pulse duration of 3,2 ms is under development. Transportation line should provide beam transfer with minimal losses of electrons and should form homogeneous distribution of the particle density at the target. Maximal value of a neutron flux is Fm=2x1013 n/(cm2s), and power of energy release in the result of nuclei fission is Pm≈ 100 kW. |
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TUP069 | Low Energy Photoemission Electron Source for Applications in THz Radiation Production and Time-Resolved Electron Microscopy | laser, cathode, radiation, FEL | 554 |
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Funding: Work supported by the Department of Education under contract P116Z010035 with Northern Illinois University. |
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TUP072 | AIRIX Diagnostic Devices for Focal Spot Size and Dose Measurements | target, diagnostics | 560 |
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Funding: CEA-DAM, Polygone d'Experimentation de Moronvilliers 51 490 Pontfaverger Moronvilliers (France). olivier.pierret@cea.fr |
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TUP073 | Tailoring the Emittance of a Charged Particle Beam with a Tunnel Emittance Meter | emittance, ion, brilliance, ion-source | 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 | emittance, ion, rfq, linac | 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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TUP075 | DITANET: A European Initiative in the Development of Beam Instrumentation for Future Particle Accelerators | diagnostics, ion, instrumentation, optics | 567 |
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Without an adequate set of beam instrumentation, it would not be possible to operate any particle accelerator, let aside optimize its performance. In a joint effort between several major research centres, Universities, and partners from industry, DITANET aims for the development of beyond-state-of-the-art diagnostic techniques for future accelerator facilities and for training the next-generation of young scientists in this truly multi-disciplinary field. The wide research program covers the development of beam profile, current, and position measurements, as well as of particle detection techniques and related electronics. This contribution introduces this new Marie Curie Initial Training Network, presents the DITANET partner institutes, and gives an overview of the networks broad research and training program. |
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TUP077 | Development of Screen Monitor with a Spatial Resolution of Ten Micro-meters for XFEL/SPring-8 | target, vacuum, focusing, undulator | 573 |
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At SPring-8, the 8 GeV linac for an X-ray free electron laser (XFEL) is now under construction. In order to realize the XFEL, highly qualified electron beams are required. A measurement of spatial structure of such beam is very important for the beam tuning of XFEL. The spatial structure is measured with a screen monitor, which we now develop. The resolution of the measurement is required within 10 um. The screen monitor comprises a vacuum chamber with a thin metal (100 um, SUS) foil to emit OTR, lenses for focusing and a CCD camera system. The main feature of the monitor is a bright and high-resolution optical system. In order to realize this system, the lenses are placed close to the foil, the distance between the lenses and the foil is 100 mm, and the lenses have a large diameter (2 in.). This optical-geometrical structure also contributes much to reduce the airy radius of a near field image. Although the range of an observation wavelength is wide as which is form 400 to 800 nm, the resolution of the measurement on the foil is calculated as 2.5 um. The experimental data of the developed screen monitor also suggested the same resolution. |
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TUP078 | Development of Integrator Circuit for Charge Monitoring | controls, linac, injection, storage-ring | 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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TUP080 | Numerical Study of a New Bunch Length Monitor Utilizing a Detection of Electromagnetic Fields in Millimeter-Wave Region | radiation, vacuum, linac, dipole | 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 | linac, beam-loading, 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, linac | 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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TUP086 | Initial Commissioning of a Dual-Sweep Streak Camera on the A0 Photoinjector | laser, emittance, cavity, 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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TUP089 | Electron Beam Timing Jitter and Energy Modulation Measurements at the JLab ERL | FEL, wiggler, instrumentation, cavity | 606 |
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When operating JLab high current ERL a strong reduction of the FEL efficiency was observed when increasing the average electron beam current. Investigating the FEL efficiency drop-off with the electron beam average current we also have measured the electron beam phase noise and the fast energy modulations. The so-called phase noise is essentially a variation of the time arrival of the electron bunches to the wiggler. That could be a very effective way of reducing the FEL efficiency if one takes in to account that the accelerator is routinely operated with the RMS bunch length of about 150 fs. Under a fast energy modulation we mean a modulation which can not be followed by the FEL due to its time constant, defined by the net gain. Such a modulation also could be a possible cause of the efficiency drop-off. Having the measurements made we could rule out the FEL efficiency drop-off due to either the fast energy modulation or the phase modulation. We also have learned a lot about instrumentation and techniques necessary for this kind of beam study. In this contribution we describe the used instrumentation and present results of the measurements. |
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TUP090 | Optical Diffraction Radiation Measurements at CEBAF | radiation, background, diagnostics, beam-losses | 609 |
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Optical diffraction radiation (ODR) is a promising technique, which could be used for non interceptive beam size measurements at future light sources. An ODR diagnostic station was designed and installed on a CEBAF transfer beam line. The purpose of the setup is to evaluate experimentally the applicability range for an ODR based non interceptive beam size monitor and to collect data to benchmark numerical modeling of the ODR. An extensive set of measurements were made at the electron beam energy of 4.5 GeV. The ODR measurements were made for both pulsed and CW electron beam of up to 80 uA. The wavelength dependence and polarization components of the ODR were studied using a set of insertable bandpass filters and polarizers. The typical transverse beam size during the measurements was ~150 microns. Complete ODR data, wavelength and polarization, were recorded for different beam sizes and intensities. The beam size was also measured with an optical transition radiation (OTR) as well as wire scanner located next to the ODR station. In this contribution we describe the experimental setup and present first results of the measurements with the comparison to the numerical simulations. |
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TUP092 | Laser-Based Profile and Energy Monitor for H- Beams | laser, space-charge, ion, linac | 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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TUP094 | Development of a Photocathode RF Gun for an L-Band Electron Linac | cavity, gun, cathode, emittance | 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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TUP095 | Development of a Cs-Te Cathode RF Gun at Waseda University | cavity, gun, cathode, resonance | 624 |
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Funding: Work supported by MEXT High Tech Research Project HRC707, JSPS Grant-in-Aid for Scientific Research (B)(2) 16340079 |
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TUP097 | Measurements and Modeling at the PSI-XFEL 500 kV Low-Emittance Electron Source | emittance, cathode, 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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TUP098 | Lienard-Wiechert Potentials and Method of Images in RF Free Electron Laser Photoinjector | cathode, acceleration, cavity, electromagnetic-fields | 633 |
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Based on Lienard-Weichert method of retarded potentials and the potential due to the image of charges on the cathode, a rigorous relativistic description of the beam transport inside the rf-photoinjector is presented. The velocity dependent effects are explicitly taken into account in a complete analytical description. Simulations are presented for parameters of the ELSA photo-cathode. |
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TUP100 | The Optimization of a DC Injector for the Energy Recovery Linac Upgrade to APS | emittance, laser, gun, linac | 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 | photon, emittance, 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, space-charge, emittance, 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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TUP104 | A High-Brightness Low-Energy Photoinjector Option for the Fermilab Electron Accelerator Facility | radiation, synchrotron, synchrotron-radiation, collective-effects | 648 |
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Funding: Work supported by Fermi Research Alliance LLC. Under DE-AC02- 07CH11359 with the U.S. DOE and by the Department of Education under contract P116Z010035 with Northern Illinois University |
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TUP106 | Simulation of Field-Emission Cathodes for High Current Electron Injectors | cathode, simulation, FEL, gun | 652 |
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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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TUP111 | Longitudinal Bunch Lengthening Compensation in a High Charge RF Photoinjector | emittance, gun, booster, 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, linac, 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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TUP113 | Emittance Exchange at the Fermilab A0 Photoinjector | cavity, emittance, optics, dipole | 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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TUP115 | Beam Transport Effects for ECRIS | ion, extraction, ECRIS, ion-source | 670 |
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Experimental results from ion beams, extracted from an Electron Cyclotron Resonance ion source (ECRIS) are presented and compared with different models used for simulation. The model for the simulation has to satisfy different facts: The energy of ions within the plasma is in the eV-range. Electrons have a different energy distribution: there are hot electrons (up to MeV range), but also low energy electrons, responsible for charge neutrality within the plasma. Because the gyration radius of ions is within the mm-range and below, ions can be extracted only if they are located on a magnetic field line which goes through the extraction aperture. Because of the gradient dBz/dz of the mirror field only these ions can be extracted, which have enough energy in direction of the field line. These conditions are fulfilled for ions which are going to be lost through the loss cone created by the hexapole. The extracted beam shows a typical behavior for an ECRIS: when the beam is focused by a lens (here a solenoid) directly behind extraction, the initial round and hollow beam develops wings with a 120-degree symmetry. These wings has influence on the beam emittance. |
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TUP117 | Development of Ultra-Low Emittance Injector for Future X-Ray FEL Oscillator | emittance, linac, 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 | linac, ion, rfq, booster | 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 | linac, 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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|
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TH104 | An Overview of Linac Ion Sources | ion, plasma, ECR, ion-source | 740 |
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Funding: This work was supported by the US Department of Energy under Contract Number DE-AC52-06NA25396 |
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|
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TH201 | Charge State Boosters for Radioactive Ion Acceleration | ion, ECRIS, plasma, ion-source | 745 |
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For the post acceleration of radioactive ions produced at ISOL facilities the increase of the charge state is essential to reduce the A/q requirements of the accelerators. Many of those existing or proposed facilities are relying on the performance of charge state boosters of EBIS or ECRIS type. Although, in principle both types of sources can be used in pulsed or continuous mode operation an EBIS is better suited for pulsed beams whereas an ECRIS is most efficient in a continuous mode. The present state of the art with respect to existing data of both sources will be presented and potential future developments will be discussed. Latest results from the on line commissioning of a PHOENIX ECRIS charge breeder at ISAC will be presented. |
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THP001 | Nb-RRR Sheet Inspection by Means of Ultrasonic Microscopy | cavity, niobium, diagnostics, superconducting-RF | 771 |
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Nb-RRR sheet material is one of the key components of super conducting linear particle accelerator projects (e.g. XFEL, ILC). The high quality requirements led to sophisticated quality systems in the manufacturing line. A major aspect is the development of non-destructive inspection methods for the detection of surface defects, delaminations, and inclusions. Up to now the standard inspection technologies for quality assurance of Nb-RRR sheet material are based on electromagnetic techniques, e.g. SQUID and eddy current. For these methods the detection limit is in the range of 0.1 mm. Ultrasonic microscopy (USM) in the frequency range of 1 GHz is a well established and economic technique for non-destructive surface inspection. For volume inspection of sheet material ultrasonic frequencies of 50 to 100 MHz are applied. For Nb-RRR sheets with typical thickness of 2.8 mm a detection limit of 0.1 mm is expected. First results of USM on Nb-RRR sheet material are presented. |
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THP016 | Analysis of Quenches Using Temperature Mapping in 1.3 GHz SCRF Cavities at DESY | cavity, superconducting-cavity, superconductivity, synchrotron | 812 |
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The local thermal breakdown (quench) behavior of one- and nine-cell SCRF Nb accelerator cavities is investigated systematically. For more than 50 cavities, temperature mapping data have been analyzed with respect to surface preparation, Nb material etc. Results on quench location and characteristic correlations are presented. |
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THP027 | Welding Helium Vessels to the 3.9 GHz Superconducting Third Harmonic Cavities | cavity, monitoring, cryomodule, emittance | 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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THP035 | Multipactor in Minimum Electric Field Regions of Transmission Lines and Superconducting RF Cavities | cavity, multipactoring, simulation, superconducting-RF | 860 |
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Funding: Work is supported by the National Science Foundation grant PHY 0131508 *S. Belomestnykh and V. Shemelin, "Multipacting-free Transitions between Cavities and Beam-pipes," submitted to Nuclear Instruments and Methods in Physics Research A. |
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THP037 | RF Design of a Spoke Resonator for High Power Free-Electron Lasers | HOM, free-electron-laser, laser, acceleration | 866 |
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Funding: Supported by the High-Energy Laser Joint Technology Office |
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THP043 | Preliminary Results from Multi-Cell Seamless Niobium Cavities Fabricated by Hydroforming | cavity, niobium, cryogenics, vacuum | 882 |
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Funding: This manuscript has been partially authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. |
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THP045 | Twisted Structures and Their Application as Accelerating Structures | cavity, simulation, superconducting-cavity | 888 |
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Funding: This work has been sponsored by ORNL-SNS. The Spallation Neutron Source is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. |
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THP057 | Development of RF Cavities for the SHB System of the L-band Electron Linac at Osaka University | cavity, linac, resonance, 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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THP058 | Accelerating Structure for C-Band Electron Linear Accelerator Optimization | impedance, coupling, vacuum, cavity | 921 |
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The results of analysis and comparison of different linear accelerator designs for 10 MeV facility powered by 4.5 MW klystron on 5712 MHz operation frequencies presented. Several concepts of accelerator including standing wave and traveling wave ones with either rf or magnetic focusing were considered. Cells geometry and beam dynamics parameters in these types of accelerators featuring high capture factor were obtained using numeric simulation methods. The computer simulation code for traveling wave linac optimization based on beam dynamics with space charge consideration was developed. Accelerating structures and input coupler for traveling wave linac along with standing wave one were designed. The task of energy variation was solved. |
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THP066 | Breakdown in Pressurized RF Cavities | cavity, simulation, vacuum, emittance | 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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THP075 | X-Band Traveling Wave RF Deflector Structures | impedance, kicker, emittance, factory | 966 |
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Funding: Work supported by U.S. Department of Energy, contract DE-AC02-76SF00515 (SLAC) |
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THP086 | Cold Cathode Electron Tube Toward Plenty Multi Beam Tube | cathode, cavity, high-voltage, simulation | 990 |
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The multi beam electron tube with a lot of beam pipes is required for the low applied voltage and the high frequency because the efficiency has a limit according to the perveance. However, the total heater power becomes too high if many thermal cathodes are used. Thus the cold cathode such as the carbon nano tube (CNT) is suitable for such a multi beam electron tube. Further the cold cathode has the advantage to work as a switching device since the metal grid close to the cathode can be used. The design and the fundamental test of the partial model will be presented. |
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THP122 | Overview of the First Five Refurbished CEBAF Cryomodules | cryomodule, cavity, vacuum, linac | 1084 |
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Funding: Authored by JSA, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 |
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FR101 | 8-GeV C-Band Accelerator Construction for XFEL/SPring-8 | klystron, high-voltage, FEL, cavity | 1090 |
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The 8 GeV C-band electron linear accelerator is under construction at the SPring-8 site aiming at generating an FEL X-ray beam in 2010. C-band accelerator technology has been developed initially at KEK for the e+e- linear collider project, and employed at the XFEL project in Japan. Since C-band generates a high gradient acceleration field as high as 35 MV/m, the total length of the accelerator fits within 400 m, including the injector and three bunch compressors. C-band uses normal conducting rf technology, thus it runs in pulse mode at 60 Hz, which is well suited to XFEL operation and is less expensive. The talk will cover the current status of the XFEL project and hardware production. |
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FR102 | Commissioning of the LCLS Linac | emittance, laser, linac, FEL | 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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FR103 | Operation of FLASH as an FEL User Facility | FEL, radiation, photon, gun | 1100 |
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FLASH, the FEL user facility at DESY, is operated with an electron beam energy up to 1 GeV corresponding to a photon wavelength down to 6.5 nm. The full year 2008 is dedicated to beam operation: about half of the time is scheduled for FEL users, and the rest for accelerator and FEL physics studies. Operational experience gathered at FLASH is very important not only for further improvements of the FLASH facility itself, but also for the European XFEL and for the ILC R&D effort. This talk reports our experience operating FLASH as a user facility. Failure statistics are included as well. |
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FR104 | Review of Advanced Laser Technologies for Photocathode High-Brightness Guns | laser, polarization, cathode, gun | 1105 |
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I developed a 3-D pulse shaping system in UV as an ideal laser for yearlong stable photoinjector. At SPring-8, the laser's pulse-energy stability has been improved to 0.7~1.4% at the UV (263 nm) under the laser environmental control included humidity. In addition, the ideal spatial and temporal profiles of an UV-laser pulse are essential to suppress emittance growth in an rf gun. I apply a deformable mirror that automatically shapes the spatial profile with a feedback routine, based on a genetic algorithm, and a pulse stacking system consisting of three birefringence Alpha-BBO crystal rods for temporal shaping at the same time. The 3D shape of the laser pulse is spatially top-hat (flattop) and temporally a square stacked chirped pulse. Using a 3D-shaped laser pulse with diameter of 0.8 mm on the cathode and pulse duration of 10 ps (FWHM), we obtain a normalized emittance of 1.4 pi mm mrad with a beam energy of 26 MeV. To keep the mirror away from beam axis, I developed a new hollow laser incidence with an axicon final focusing. Furthermore, I am developing a laser-induced Schottky-effect-gated photocathode gun using Z-polarization of the laser source with the hollow incidence. |
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FR105 | Billion Particle Linac Simulations for Future Light Sources | linac, 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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