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| MOPC001 |
The Status of TAC Infrared Free Electron Laser (IR-FEL) Facility
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undulator, electron, linac, laser |
61 |
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- A. Aksoy, Ö. Karsli, B. Ketenoglu, O. Yavas
Ankara University, Faculty of Engineering, Tandogan, Ankara
- A. K. Ciftci, Z. Nergiz
Ankara University, Faculty of Sciences, Tandogan/Ankara
- E. Kasap
Gazi University, Faculty of Science and Arts, Ankara
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Turkish Accelerator Complex (TAC) Infrared Free Electron Laser (IR-FEL) project was approved by State Planning Organization (DPT) as a first step of the national project. The facility will consist of 15 40 MeV superconducting electron linac and two different optical cavity systems with different undulator period length to obtain FEL in 2 185 microns wavelengths range. In this study, the results of optimization and current status of TAC IR FEL facility is presented. The facility will give opportunity to search applications in material science, biotechnology, nonlinear optics, semiconductors, medicine and chemistry using IR-FEL in Turkey and our region.
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| TUPC030 |
Transverse Electron Beam Size Effect on the Bunch Profile Determination with Coherent Radiation Diagnostics
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optics, radiation, electron, diagnostics |
1113 |
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- O. Grimm, H. Delsim-Hashemi, J. Rossbach
Uni HH, Hamburg
- V. Balandin, N. Golubeva
DESY, Hamburg
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Longitudinal diagnostics of electron bunches can be done by measurement of coherent radiation (e.g., in the form of transition radiation) and subsequent extraction of the form factor. By measuring short wavelengths, fine structures in the bunch can be resolved. However, the form factor depends on the three-dimensional charge density distribution, and the usual practice of considering only a one-dimensional line charge in interpreting the radiation spectra is questionable, as the finite transverse extend of the electron bunch can reduce the form factor magnitude at short wavelengths. An experimental study of this issue using a two stage single shot spectrometer has been carried out at the FLASH free-electron laser at DESY, Hamburg. The coherent transition radiation spectra for two beam optics settings were recorded and compared. In one setting the transverse beam size at the transition radiation target screen has been blown up by a factor of about 3.5 compared to the second setting. The ratio of these two spectra shows a suppression of radiation intensity at short wavelengths, as expected from a theoretical calculation. In this paper the result of this study is presented.
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| TUPP003 |
Automatic Generation of SEU Immunity for FPGA Based Electronics for Accelerators
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controls, simulation, radiation, laser |
1529 |
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- M. K. Grecki, G. W. Jablonski, W. Jalmuzna, D. R. Makowski
TUL-DMCS, Łódź
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The modern accelerator control systems nowadays are build using digital technology based on FPGA circuits. However, digital circuits working in radioactive environment are exposed to disturbing effects, in particular SEU (Single Event Upset)*. One of the countermeasure is a redundancy in circuit that allow to detect and correct errors caused by radiation**. Unfortunately CAD software provides no support to automatically include required redundancy in the FPGA project. Moreover, optimization procedure removes all redundant parts and special effort must be made to prevent that. The paper presents a software environment to process VHDL description of the circuit and automatically generate the redundant blocks together with voting circuits. The generated redundancy uses Triple Module Redundancy (TMR) scheme. It also supports the VHDL simulation with SEUs in order to enable identification of the most sensitive components***. Since the TMR is costly, the designer can indicate which parts of the circuit should be replicated based on the results of simulation.
*Baumann. Neutron-induced…, Int. Rel. Phys. Symp. 2000.
**Hentschke et al. Analyzing Area…, Symp. ICs and Systems Design, SBCCI02.
***Grecki. VHDL Simulation…, Nanotech 2006, Vol.1.
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| TUPP018 |
Impact of Electromagnetic Fields in TESLA RF Modules on Transverse Beam Dynamics
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emittance, simulation, electron, undulator |
1568 |
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- E. Prat, W. Decking, M. Dohlus, T. Limberg, I. Zagorodnov
DESY, Hamburg
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Transverse electric fields in TESLA rf modules exist on one hand because of deformations of the longitudinal accelerating field in the presence of rf structure misalignments or in the vicinity of asymmetrically machine parts like input couplers. On the other hand, the beam itself induces transverse wake fields if it does not travel through the center of a perfectly rotationally symmetric structure. Transverse deflecting fields deflect beam particles. The average deflection causes a change in the beam trajectory; the phase dependence of the transverse field leads to a variation of the transverse kick along the longitudinal position of the bunch and thus in general to a change in projected emittance. If the strength of the transverse field component varies along the transverse direction itself, slice emittance will be also affected. We will present the amplitudes and spatial variations of transverse fields generated by the mechanisms described above, and discuss their impact on beam trajectories and shape.
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| WEIM03 |
Industrialization of Superconducting Accelerator Module Production
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vacuum, linac, alignment, collider |
1964 |
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- B. Petersen
DESY, Hamburg
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As part of the EUROFEL Design Study, two industrial partners recently took part in the assembly of superconducting TESLA modules for FLASH. The aim was to transfer the module assembly knowledge to industry and to analyse the assembly sequence to perpare for industrial production for future projects such as the XFEL. This talk should discuss the conclusions of this study and identify issues that must be considered when transferring SRF technology to industry.
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Slides
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| WEPC129 |
Undulator Demagnetization due to Radiation Losses at FLASH
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undulator, radiation, quadrupole, permanent-magnet |
2308 |
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- J. Skupin, B. Faatz, Y. Li, J. Pflueger, T. Vielitz
DESY, Hamburg
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The free-electron laser FLASH was set up at DESY Hamburg in 2004. It is a high-gain, single pass FEL which operates in the VUV and soft X-ray wavelength regime. To monitor the demagnetization of the undulator structures due to radiation losses a small test undulator was installed. This dosimetric undulator (DU) consists of a short piece of magnetic undulator structure with only 3 pole pairs and corresponding magnets. It is positioned in front of the first undulator module where a high dose rate is to be expected. The accumulated dose of DU and undulator system is derived by weekly measurements with thermoluminescence dosimeters (TLDs). The DU is dismounted and magnetically measured regularly. Based on these measurements a (maximal) relative demagnetization rate of about 5*10-4/kGy was derived. In view of this result magnetic measurements on one of the undulators from TTF1 (the predecessor of FLASH) were reviewed. They show a relative demagnetization rate of about 2*10-4/kGy which is lower but still in the same range as the result from FLASH. FEL simulations to analyse the influence of the demagnetization on the SASE process are in progress.
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| FRXCGM01 |
High Quality GeV Electron Beams from Plasma-Laser Accelerators
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electron, laser, synchrotron, plasma |
3733 |
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- W. Leemans
LBNL, Berkeley, California
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Accelerators are essential tools of discovery and have many practical uses. At the forefront of accelerator technology are the machines that deliver beams for particle physics, for synchrotron and free electron based radiation sources. The technology that drives these accelerators is extremely sophisticated but is limited by the maximum sustainable accelerating field. This impacts the size and cost of the device. More than two decades ago, lasers were proposed as power source for driving novel accelerators based on plasmas as the accelerating medium. An overview will be presented of what these devices can produce to date, including the 2004 demonstration of high quality electron beams* and the 2006 demonstration of GeV class beams from a 3 cm long accelerating structure**. We then discuss the key challenges for broad applicability of the technology and our goal of making a laser accelerator driven a VUV/soft x-ray free electron laser.
* C. G.R. Geddes et al., Nature 431, 538-541 (2004); S. P.D. Mangles et al., ibidem, p.535-538; J. Faure et al., ibidem, p. 541-544.
** W. P. Leemans et al., Nature Physics 2, 696-699 (2006).
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Slides
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