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| MO101 |
Advanced Analysis in Nanospace: Research with the XFEL
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1 |
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Little happens in industrialised countries without the use of high-tech materials which are the building blocks of all modern technologies ranging from information, communication, health, energy and environment to transport. In the last decades the development of novel materials has progressed at a breathtaking rate. This has become possible through our microscopic insight into the atomistic structure of condensed matter which finally enabled us to assemble new material systems atom-by-atom. These days, we are facing a revolution in the investigation of nanospace: Through new concepts in accelerator physics, electrons can be forced to emit short-pulsed x-ray laser radiation. Such a futuristic European x-ray free electron laser (XFEL) laboratory is currently being constructed and will allow mankind to finally get holographic snapshots of the motion of atoms and electrons in materials. Ultimate insights into matter, as the realtime-observation of the formation and the breaking of molecular bonds, sound like science fiction, but could become reality in less than a decade, if Europe embarks today into this bold adventure which will lead us into unexplored dimensions of nanospace.
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| MO102 |
Accelerator Layout of the XFEL
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2 |
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- R. Brinkmann
DESY, Hamburg
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The X-ray Free Electron Laser XFEL is a 4th generation synchrotron radiation facility based on the SASE FEL concept and the superconducting TESLA technology for the linear accelerator. In February 2003 the German government decided that the XFEL should be realized as a European project and located at DESY/Hamburg. The Ministry for Research and Eduation also announced that Germany is prepared to cover half of the investment and personnel costs of the project. This paper gives an overview of the overall layout and parameters of the facility, with emphasis on the accelerator design, technology and physics.
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Transparencies
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| MO201 |
Linac Coherent Light Source (LCLS) – Accelerator System Overview
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7 |
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- P. Krejcik, Z. Huang, J. Wu
SLAC, Menlo Park, California
- P. Emma
SLAC/ARDA, Menlo Park, California
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The Linac Coherent Light Source (LCLS) will be the world's first x-ray free-electron laser (FEL). Pulses of LCLS x-ray FEL will be several orders of magnitude brighter and shorter than most existing sources. These characteristics will enable frontier new science in several areas. To ensure the vitality of FEL lasing, it is critical to preserve the high quality of the electron beam during the acceleration and compression. We will give an overview of the LCLS accelerator system. We will address design essentials and technique challenges to satisfy the FEL requirements. We will report studies on the microbunching instability suppression via a Laser-Heater. The studies clearly prove the necessary of adding the Laser-Heater and show how effectively this Laser-Heater suppresses the instability by enhancing the Landau damping. We will report how to minimize the sensitivity of the final energy spread and the peak current to various system ‘jitters’. To minimize this sensitivity, a feedback system is required together with other diagnostics. With all these considerations, full start-to-end simulations show saturation at 1.5 Å, though the LCLS is expected to be a very challenging machine.
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Transparencies
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| TU202 |
Low Emittance 500 kV Thermionic Electron Gun
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261 |
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- K. Togawa, H. Baba, T. Inagaki, K. Onoe, T. Shintake, T. Tanaka
RIKEN Spring-8 Harima, Hyogo
- H. Matsumoto
KEK, Ibaraki
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A 500 kV pulsed electron gun has been constructed for the injector system of the SASE-FEL project at SPring-8 (SCSS project). A CeB6 single crystal was chosen as a thermionic cathode, because of its excellent emission properties. We have succeeded in generating a 500 keV beam with 1 A peak current and 3 μs FWHM. The beam was very stable with low jitter. The beam emittance has been measured by means of double-slits method, and the normalized rms emittance of 1.1 π·mm·mrad has been obtained. We report on the experimental result on the emittance measurement of the CeB6 electron gun.
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Transparencies
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| TUP41 |
Multi-Bunch Beam Dynamics Studies for the European XFEL
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357 |
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In the X-ray free electron laser planned to be built at DESY (TESLA XFEL) the acceleration of the electron bunches will be made with 9-cell superconducting cavities. These cavities have been initially developed within the TESLA linear collider study. The impact of the higher order modes (HOM) has been shown to be within the acceptable beam dynamics limits for the collider. For the XFEL the dynamics is relaxed from point of view of multi-bunch effects (e.g. shorter length, higher emittance). However the lower energy and different time structure of the beam make the study of the HOM effects in the XFEL linac necessary. Multi-bunch beam dynamics studies are ongoing. The results of the HOM measurements at the TESLA Test Facility are used. Several options for the beam structure, as necessary for various applications, are studied. The results will be discussed.
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Transparencies
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| TUP42 |
Beam Optics Studies for the TESLA Test Facility Linac
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360 |
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- P. Castro, V. Balandin, N. Golubeva
DESY, Hamburg
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The aim of the TESLA Test Facility Linac is to create electron bunches of small transverse emittance and high peak current with energies up to 1 GeV for the VUV-FEL at DESY. The linac consists of a RF photo-cathode gun, a superconducting linac, two magnetic chicanes (for bunch compression), a long undulator magnet section and a beam line bypassing the undulator (for commissioning purposes). A study of (linear) beam optics of the linac is presented for the case of beam commissioning (and beam measurements), FEL operation and long bunch train operation. The requirements of each part of the linac upon the optics are discussed in detail and an appropriate solution for each case is shown, as well as the matching solution to the rest of the accelerator. The chromatic properties of the linac have been studied also.
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| TUP43 |
The Superconducting CW Driver Linac for the BESSY-FEL User Facility
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363 |
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- J. Knobloch
BESSY GmbH, Berlin
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A CW FEL User Facility for the VUV to soft X-ray spectral range based on a cascaded HGHG-FEL scheme is planned at the BESSY site. The Technical Design Report has recently been submitted to the German Wissenschaftsrat. Beam acceleration to 2.3 GeV is provided by a 144-cavity superconducting driver linac based on TESLA technology modified for CW operation. Initially, a high-rep-rate normal-conducting photoinjector will be used but a fully CW superconducting version is being investigated for a future upgrade. Bunch compression to 2 kA peak current is achieved in a three-stage scheme involving two bunch compressors and an arc. An overview of the linac layout, including the rf and cryogenic distribution, is provided here. We also discuss the impact of CW operation and the modifications to the TESLA technology that are necessary. Predictions of the linac performance are also given.
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Transparencies
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| TUP44 |
Linac Upgrades for FERMI@ELETTRA
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366 |
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- G. D'Auria, R.J. Bakker, P. Craievich, G. De Ninno, S.D. Di Mitri, M. Ferianis, P.G. Pangon, R.L. Rumiz, T.L. Tosi, D. Zangrando
Sincrotrone Trieste S.C.p.A., Basovizza, Trieste
- C. Bocchetta, M. Danailov, B. Diviacco, V. Verzilov
ELETTRA, Basovizza, Trieste
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To fulfill the stringent requirements expected from the FERMI project, the existing Linac needs some modifications in the layout and an upgrading of the present plants. Moreover, for the next two years, until the new injection system (now under construction) is fully commissioned, the Linac has to be kept in operation as injector for the ELETTRA Storage Ring. Therefore most of the planned activities have to be carried out without interfering with the normal operation of the machine. Details on the new Linac layout and related activities are discussed.
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| TUP45 |
Extended Parametric Evaluation for 1 Å FEL - Emittance and Current Requirements
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369 |
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- M. Pedrozzi, G. Ingold
PSI, Villigen
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In the synchrotron radiation community there is a strong request for high brightness, coherent X-ray light pulses, especially in the 1 to 0.1 nm wave length range. A Free Electron Laser (FEL), driven by a linear single pass accelerator, is today the most promising mechanism able to produce such radiation. Since the electron beam brightness plays a major role in the laser saturation process and in the final energy of the driving linac, many laboratories are presently working on a new generation of low emittances sources. The present analysis will give an indication about the FEL behaviour and the undulator parameters versus the slice beam quality (emittance, current, energy spread).
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| WE203 |
Challenges of Linac Driven Light Sources
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543 |
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- C. Bocchetta
ELETTRA, Basovizza, Trieste
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The use of linacs allows novel light sources to be conceived by not being limited by equilibrium dynamics or IBS effects. These new sources can be single pass or recirculated (with or without energy recovery) or linac augmented storage rings. They allow tuneable polarised radiation of unprecedented brilliance, short pulse lengths that may reach the atto-second scale and full coherence. Both SC and NC machines are being proposed, designed and constructed. Photon output characteristics range from incoherent synchrotron radiation to SASE to seeded HGHG. The proposed beams can be low to high average current and pulse time structures range from CW to highly variable with mutual exclusion amongst different forms of operation. The multiple challenges of these machines reside not only in the requirement of beams of extremely high quality (energy, emittance, energy-spread and temporal stability) for the brightest, shortest wavelength sources but also in the demanding technologies and control of beam-machine interactions for the high current energy recovery ones. The paper gives an overview of these broad challenges and of the directions taken to reach the objectives of a user facility.
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Transparencies
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