EPAC08 - List of Keywords (undulator)

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undulator

Paper	Title	Other Keywords	Page
MOYAGM01	Review of DESY FEL Activities	radiation, electron, laser, emittance	7
	J. Rossbach Uni HH, Hamburg J. Rossbach DESY, Hamburg
	A general overview will be given of DESY FEL activities. Overview of the technological upgrades and results of beam commissioning of the FLASH FEL. The talk will cover the latest results from FLASH at the shortest wavelengths. A description will be given of critical systems and performance. The status of the XFEL will be given, including integration of FLASH technology.
	Slides

MOPC001	The Status of TAC Infrared Free Electron Laser (IR-FEL) Facility	electron, linac, laser, free-electron-laser	61
	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
	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.

MOPC002	Extension of the FERMI FEL1 to Shorter Wavelengths	electron, simulation, radiation, laser	64
	E. Allaria ELETTRA, Basovizza, Trieste G. De Ninno University of Nova Gorica, Nova Gorica
	We propose a modification of the first stage (FEL-1) of the FERMI@Elettra project in order to extend the wavelength from the original limit of 40 nm down to 20 nm. The modified setup takes advantage of a shorter radiator undulator period. We present the numerical studies that have been carried out to compare the expected performance of the new FEL-1 with that of the original FERMI setup. Results show that the modified configuration represents a good alternative to the second stage of the project (FEL-2) in the wavelength range between 40 nm and 20 nm. C. J. Bocchetta et al. 'FERMI@Elettra Conceptual Design Report' ST/F-TN-07/12 (2007)

MOPC003	Estimation of Undulator Requirements for Coherent Harmonic Generation on FERMI@Elettra	electron, simulation, bunching, laser	67
	E. Allaria, G. De Ninno, B. Diviacco ELETTRA, Basovizza, Trieste
	The FERMI project is devoted to the realization of a FEL user facility based on the principle of coherent harmonic generation (CHG). The advantages of such a method (with respect, e.g., to self amplified spontaneous emission) is that the output properties of the light are strongly determined by the interaction of the seed laser with the electron beam within the modulator undulator. In CHG FELs therefore, in addition to the requirements for the radiator where FEL radiation is produced, it is important to understand and satisfy the requirements for the modulator. In this work, we present a study focused on the first stage (FEL-1) of the FERMI@Elettra setup. The study aims at providing an estimation of the undulator requirements in terms of magnetic field accuracy for both the modulator and the radiator. The work is based on numerical simulations of the FEL-1 using the numerical code GINGERH [1]. The required undulator tolerances have been obtained by means of a large number of simulation runs taking into account different sets of undulator parameters. [1] W. Fawley, “A User Manual for GINGER-H and its Post-Processor XPLOTGINH” LCLS-TN-07-YY Technical note, Lawrence Berkeley National Laboratory (2007)

MOPC005	The ARC-EN-CIEL Radiation Sources	radiation, electron, laser, brilliance	73
	M.-E. Couprie, M. Labat CEA, Gif-sur-Yvette C. Benabderrahmane, O. V. Chubar, G. Lambert, A. Loulergue, O. Marcouillé SOLEIL, Gif-sur-Yvette C. Bruni LAL, Orsay L. Giannessi ENEA C. R. Frascati, Frascati (Roma)
	The ARC-EN-CIEL project proposes a panoply of light sources for the scientific community on a 1 GeV superconducting LINAC (phase 2) on which two ERL loops (1 and 2 GeV) are added in phase 3. LEL1 (200-1.5 nm), LEL2 (10-0.5 nm) and LEL4 (2-0.2 nm) are three kHz High Gain Harmonic Generation Free Electron Laser sources seeded with the High order Harmonics generated in Gas, with 100-30 FWHM pulses. A collaboration, which has been set-up with the SCSS Prototype Accelerator in Japan for test this key concept of ARC-EN-CIEL, has led to the experimental demonstration of the seeding with HHG and the observation up the 7th non linear harmonic with a seed at 160 nm. Besides. LEL3 (40-8 nm) installed on the 1 GeV loop is a MHz FEL oscillator providing higher average power and brilliance. In addition, in vacuum undulator spontaneous emission source extend the spectral range above 10 keV and intense THz radiation is generated by edge radiation of bending magnets. Optimisations and light sources characteristics are described.

MOPC011	Improvement and Recent Results of the DELTA Storage Ring FEL	laser, electron, alignment, storage-ring	88
	H. Huck, R. Burek, G. Schmidt, K. Wille DELTA, Dortmund
	Several modifications to the storage ring FEL at DELTA have been conducted, in order to enhance speed and reproducability of mirror alignment as well as flexibility of electron beam settings. We present the new hardware design and experimental results at a laser wavelength of 470 nm. Lasing was achieved with different filling patterns, and the output power of the FEL was measured. By modulating the accelerating RF the laser macropulses can be forced into a Q-switch mode, varying between roughly 10 and 250 Hz without significant loss of outcoupled average power. A special input optics setup for a streak camera enables simultaneous measurement of electron beam and laser pulse dynamics, to study the correlations between them. Recent measurements will be presented.

MOPC012	PSI XFEL Simulations with SIMPLEX and GENESIS	simulation, electron, emittance, radiation	91
	V. G. Khachatryan, V. M. Tsakanov CANDLE, Yerevan R. J. Bakker PSI, Villigen V. V. Sahakyan, A. Tarloyan YSU, Yerevan
	The numerical simulation results of the SASE FEL process for PSI XFEL project are presented. The main purpose of the investigations using FEL simulation codes SIMPLEX and GENESIS is the reliable definition of the undulators design parameters (K value, period, segment length, number of segments) that provide desirable radiation characteristics such as wavelength, bandwidth, saturation length, peak power and the brightness.

MOPC013	Effect of Jitter and Quadrupole Alignment Errors on SASE FEL Performance	radiation, quadrupole, electron, simulation	94
	V. G. Khachatryan, A. Tarloyan, V. M. Tsakanov CANDLE, Yerevan W. Decking DESY, Hamburg
	Numerical simulations of the radiation process at the European XFEL project are presented. The impact of quadrupole misalignments on the saturation length and saturation power is investigated using the simulation codes SIMPLEX and GENESIS. The influence of trajectory steering in the presence of BPM misalignments on the FEL performance is analyzed. The study is performed for the SASE 1 undulator designed for 0.1nm radiation wavelength.

MOPC014	Optimization of the Focusing Lattice for European XFEL	lattice, simulation, focusing, radiation	97
	V. G. Khachatryan, A. Tarloyan, V. M. Tsakanov CANDLE, Yerevan W. Decking DESY, Hamburg V. V. Sahakyan YSU, Yerevan
	Detailed knowledge of the impact of the undulator section focusing lattice on the FEL performance is an important issue to ensure the stable operation of the facility with reliable tolerances. In this paper the results of numerical simulation studies for the European XFEL project are presented. The saturation length, saturation power and the spectral brightness of the SASE FEL are calculated for various focusing lattice arrangements. A focusing optics option with reduced number of FODO cells is discussed to reach the design goals with relaxed quadrupole magnet tolerances. The numerical simulations are performed using the SIMPLEX and GENESIS codes.

MOPC016	Status of the CUTE-FEL Project	linac, electron, klystron, gun	103
	S. Krishnagopal, B. Biswas, S. K. Gupta, U. Kale, A. Kumar, V. Kumar, S. Lal, P. Nerpagar, K. K. Pant, A. Patel RRCAT, Indore (M. P.)
	We are building a Compact Ultrafast TErahertz Free-Electron Laser (CUTE-FEL), designed to lase around 80 microns, driven by a 10 MeV electron beam, and using a 5 cm period, 2.5 m long undulator. We present the latest status of the project, including acceleration and commissioning trials.

MOPC017	Operation of the UVSOR-II CHG-FEL in Helical Configuration	laser, polarization, electron, radiation	106
	M. Labat CEA, Gif-sur-Yvette M.-E. Couprie, G. Khalili SOLEIL, Gif-sur-Yvette M. Hosaka, N. Yamamoto Nagoya University, Nagoya M. Katoh, M. Shimada UVSOR, Okazaki A. Mochihashi JASRI/SPring-8, Hyogo-ken
	In the Coherent Harmonic Generation Free Electron Laser (CHG-FEL) configuration, an external laser source injected inside a first undulator modulates in energy, and consequently in phase, an electron bunch, allowing coherent radiation in a second undulator. The CHG-FEL implemented on UVSOR-II storage ring (Okazaki, Japan) consists of a 600 MeV electron beam, and of a 2.5 mJ Ti:Sa seeding laser at 800 nm wavelength, 1 kHz repetition rate, and 100 fs up to 2 ps pulse duration. Operation in planar configuration of the undulators is being characterized since 2005. Recent experiments enabled a step forward using helical configuration of the undulators. A description of the experimental setup is given, and the main results are presented: influence of seeding laser parameters (polarisation, average power, focusing) on the intensity and beam profile of the second and third coherent harmonics. Those investigations provide attractive insights for the future HGHG FEL sources, about to deliver sub-nm and sub-ps pulses.

MOPC018	Seeding the FEL of the SCSS Test Accelerator with the 5th Harmonic of a Ti: Sa Laser Produced in Gases	laser, radiation, electron, injection	109
	G. Lambert, O. V. Chubar, M.-E. Couprie SOLEIL, Gif-sur-Yvette M. Bougeard, B. Carré, D. Garzella, O. B. Gobert, M. Labat, H. Merdji, P. Salieres CEA, Gif-sur-Yvette T. Hara, T. Ishikawa, H. Kitamura, T. Shintake, M. Yabashi RIKEN/SPring-8, Hyogo K. Tahara, Y. T. Tanaka, T. Tanikawa RIKEN Spring-8 Harima, Hyogo
	We present the strong amplification of the 5th harmonic of a Ti: Sa laser (10 Hz, 100 fs) generated in a Xe gas cell, i.e. 160 nm, and the generation of intense and coherent odd and even Non Linear Harmonics (NLH) from 80 nm to 23 nm. The experiment has been carried out on the SCSS (SPring-8 Compact SASE Source, Japan) Test Accelerator FEL. This facility is mainly based on a thermionic cathode electron gun, a C-band LINAC (5712 MHz, 35 MV/m) and an in-vacuum undulator (15 mm of period, 2 sections of 4.5 m length). The external source is properly focused in the first undulator section in order to efficiently interact with the electron beam (150 MeV, 10 Hz, 0.5-3 ps). In case of high peak current mode, the 160 nm seed light is amplified by a factor of 7000 in the first undulator section. Moreover, the amplification can be observed even for very low HHG seed level. This result opens new perspectives for seeding at short wavelengths in the XUV to soft X-Ray region. Association with NLH, HGHG (High Gain Harmonic Generation) and/or cascade schemes would allow the generation of fully coherent X-ray radiations from the “water window” spectral range to the Angstrom region.

MOPC026	Status of SPARX Project	radiation, electron, linac, laser	121
	L. Palumbo Rome University La Sapienza, Roma
	The SPARX project consists in an X-ray-FEL facility jointly supported by MIUR (Research Department of Italian Government), Regione Lazio, CNR, ENEA, INFN and Rome University Tor Vergata. It is the natural extension of the ongoing activities of the SPARC collaboration. The aim is the generation of electron beams characterized by ultra-high peak brightness at the energy of 1.2 and 2.4 GeV, for the first and the second phase respectively. The beam is expected to drive a single pass FEL experiment in the range of 13.5-6 nm and 6-1.5 nm, at 1.2 GeV and 2.4 GeV respectively, both in SASE and Seeded FEL configurations.

MOPC028	Experimental Layout of 30 nm High Harmonic Laser Seeding at FLASH	electron, radiation, laser, photon	127
	H. Schlarb, S. Düsterer, J. Feldhaus, T. Laarmann DESY, Hamburg A. Azima, J. Boedewadt, H. Delsim-Hashemi, M. Drescher, S. Khan, Th. Maltezopoulos, V. Miltchev, M. Mittenzwey, J. Rossbach, R. Tarkeshian, M. Wieland Uni HH, Hamburg
	Since 2004, the free-electron laser FLASH at DESY has operated in the Self-Amplified Stimulated Emission mode, delivering to users photon beams with wavelengths between 6.5 nm and 40 nm. In 2009, DESY plans to install a 3.9 GHz RF acceleration section for the production of electron bunches with high peak currents (~kA), but ten times larger pulse durations (~250 fs) compared to the present configuration. The relaxed timing requirements of the new configuration make it possible to externally seed FLASH with high harmonics of an optical laser (sFLASH). The aim of the project is to study the technical feasibility of seeding an FEL at 30 nm with a stability suited for user operation. sFLASH will use 10 m of gap-tunable undulators installed in front of the fixed gap SASE-undulator. A chicane behind the seeding undulators will allow to extract the output radiation for a careful characterisation and for first pump-probe experiments with a resolution in the 10 fs range by combining FEL and seed laser pulses.

MOPC031	Status of X-ray FEL/SPring-8 Machine Construction	electron, emittance, gun, cathode	136
	T. Shintake RIKEN/SPring-8, Hyogo
	XFEL/SPring-8: the X-ray Free Electron Laser Project is under construction at SPring-8 site, which is aiming at generating 0.1 nm coherent radiation using 8 GeV electron beam. After the ground breaking in 2007, concrete piling has been completed. Construction of the accelerator tunnel will be completed in end of the FY2008, then machine installation will be started. The first electron beam acceleration is scheduled in FY2010. XFEL/SPring-8 based on SASE-FEL, and unique design, thermionic CeB6 gun, adiabatic bunching, C-band high gradient accelerator and in vacuum undulator. To reach 8 GeV within 400 m available tunnel length, we use 64 C-band klystron, which drives 128 accelerating tube at 37 MV/m.

MOPC033	Sapphire - A High Peak Brightness X-Ray Source as a Possible Option for a Next Generation UK Light Source	linac, gun, emittance, klystron	142
	R. P. Walker, C. Christou, J. H. Han, J. Kay Diamond, Oxfordshire R. Bartolini JAI, Oxford
	In the UK there is increasing interest in a radiation source which would provide ultra-fast (from 100 fs down to a few fs and potentially below) multi-keV X-ray pulses with high peak brightness, in order to study rapid dynamical processes in electronic and molecular systems, complementary to the newly operational Diamond Light Source which has been designed principally for high time-averaged X-ray brightness. In this paper we present the results of our initial studies for one option for a cost-effective, staged, linac based source suitable as a national facility which can act additionally as a portal to larger X-ray free-electron laser facilities in Europe, the US and Japan.

MOPC035	PULSE - A High-Repetition-Rate Linac Driver for X-ray FELs	electron, emittance, laser, gun	148
	P. H. Williams, B. L. Militsyn, H. L. Owen, M. W. Poole, N. Thompson STFC/DL/ASTeC, Daresbury, Warrington, Cheshire B. W.J. McNeil USTRAT/SUPA, Glasgow
	We describe a staged concept for a linac-based free-electron laser providing coherent tunable VUV and soft X-ray output with pulse lengths less than 10 fs. Use of recent developments in high brightness injectors and 1.3 GHz cryomodules gives stable, reliable output with very good electron beam quality and flexible pulse pattern. Options for achieving repetition rates up to 1 MHz are examined. We also consider the development and demonstration of novel FEL concepts that access photon pulses in the attosecond regime. The combination of these parameters would open up new areas in femtosecond and attosecond science.

MOPC037	Single Spike Operation in SPARC SASE-FEL	radiation, emittance, injection, simulation	154
	V. Petrillo, I. Boscolo Universita' degli Studi di Milano, Milano A. Bacci, S. Cialdi, L. Serafini INFN-Milano, Milano R. Bonifacio, M. Boscolo, M. Ferrario, C. Vaccarezza INFN/LNF, Frascati (Roma) F. Castelli Università degli Studi di Milano, Milano L. Giannessi, C. Ronsivalle ENEA C. R. Frascati, Frascati (Roma) L. Palumbo Rome University La Sapienza, Roma S. Reiche, J. B. Rosenzweig UCLA, Los Angeles, California M. Serluca INFN-Roma, Roma
	We describe in this paper a possible experiment with the existing SPARC photoinjector to test the generation of sub-picosecond high brightness electron bunches able to produce single spike radiation pulses at 500 nm in the SPARC self-amplified spontaneous emission free-electron laser (SASE-FEL). The main purpose of the experiment will be the production of short electron bunches as long as few SASE cooperation lengths and to validate scaling laws to foresee operation at shorter wavelength in the future operation with SPARX. The basic physics, the experimental parameters and 3-D simulations are discussed. Complete start-to-end simulations with realistic SPARC parameters are presented, in view of an experiment for tests on superradiant theory with the existing hardware.

MOPC038	Ultra-high Brightness Electron Beams by All-optical Plasma-based Injectors	plasma, laser, electron, emittance	157
	V. Petrillo Universita' degli Studi di Milano, Milano L. Serafini, P. Tomassini INFN-Milano, Milano
	We study the generation of low emittance high current mono-energetic beams from plasma waves driven by ultra-short laser pulses, in view of achieving beam brightness of interest for FEL applications. The aim is to show the feasibility of generating nC charged beams carrying peak currents much higher than those attainable with photoinjectors, together with comparable emittances and energy spread, compatibly with typical FEL requirements. We identified a particularly suitable regime which is based on a LWFA plasma driving scheme on a gas jet modulated in areas of different densities with sharp density gradients. Simulations show that in the first regime, using a properly density modulated gas jet, it is possible to generate beams at energies of about 30 MeV with peak currents of 20 kA, slice transverse emittances as low as 0.3 mm.mrad and energy spread around 0.4%. This beams break the barrier of 10¹⁸ A/(mm.mrad)² in brightness, a value definitely above the ultimate performances of photo-injectors, therefore opening a new range of opportunities for FEL applications. A few examples of FELs driven by such kind of beams injected into laser undulators are finally shown.

MOPC056	Challenges for Beams in an ERL Extension to CESR	linac, emittance, electron, scattering	190
	G. Hoffstaetter, I. V. Bazarov, S. A. Belomestnykh, M. G. Billing, G. W. Codner, J. A. Crittenden, B. M. Dunham, M. P. Ehrlichman, M. J. Forster, S. Greenwald, V. O. Kostroun, Y. Li, M. Liepe, C. E. Mayes, H. Padamsee, S. B. Peck, D. H. Rice, D. Sagan, Ch. Spethmann, A. Temnykh, M. Tigner, Y. Xie CLASSE, Ithaca D. H. Bilderback, K. Finkelstein, S. M. Gruner CHESS, Ithaca, New York
	Cornell University is planning to build an Energy-Recovery Linac (ERL) X-ray facility. In this ERL design, a 5 GeV superconducting linear accelerator extends the CESR ring. Currently CESR is used for the Cornell High Energy Synchrotron Source (CHESS). The very small electron-beam emittances would produce an x-ray source that is significantly better than any existing storage-ring light source. However, providing, preserving, and decelerating a beam with such small emittances has many issues. We describe our considerations for challenges such as optics, space charge, dark current, coupler kick, ion accumulation, electron cloud, intra beam scattering, gas scattering, radiation shielding, wake fields including the CSR wake, and beam stabilization.

MOPC064	Beam Losses Due to Intra-Beam and Residual Gas Scattering for Cornell's Energy Recovery Linac	beam-losses, radiation, scattering, simulation	214
	A. Temnykh Cornell University, Department of Physics, Ithaca, New York M. P. Ehrlichman, G. Hoffstaetter CLASSE, Ithaca
	In this paper we analyze particle loss rates in Cornell's x-ray Energy Recovery Linac. Because of the small beam emittances and high beam intensity, intra-beam scattering (IBS) can be a source of significant particles loss in the horizontal plane. It will result in radiation doses which should be carefully examined for adequate radiation protection. Additionally, scattering on the residual gas (RGS) causes particle losses in the vertical plane. With Mote-Carlo type simulations of the scattering processes and transport matrixes for particle-trajectory propagation we found the beam loss distribution along ERL. It indicated that 99% of the total beam loss will be due to IBS. However, the RGS contribution can not be ignored because it dominates scattering in the vertical plane causing IDs irradiation and damage. For both (IBS and RGS) processes the highest beam losses will occur at the end of deacceleration due to adiabatic anti-damping causing traverse betatron amplitudes to increase. These beamlosses can be consentrated in collimation sections. Knowing RGS beam loss rates at the ID locations, we estimate the ID’s life time and suggest a radiation protection scheme.

MOPC155	Transport System for Ion Implantation	ion, ion-source, cathode, beam-transport	439
	S. M. Polozov, E. S. Masunov MEPhI, Moscow R. P. Kuibeda, T. Kulevoy, V. Pershin, S. Petrenko, D. N. Selesnev, I. M. Shamailov, A. L. Sitnikov ITEP, Moscow
	ITEP in collaboration with MEPHI and IHE (Tomsk) develops the high intensity ion beam generation and transport systems for low energy (1-50 keV) ion implantation. Such facilities are used for semiconductor technology. The Bernas type ion source is used for ribbon ion beam production. The periodical system of electrostatic lenses (electrostatical undulator) was proposed for ribbon beam transport line. The design of transport system and the results of beam dynamics investigation are presented. The influence of the electrodes construction errors on the beam dynamics is discussed.

MOPD010	Design of XFEL facility in Harima	klystron, controls, site, heavy-ion	466
	T. Kato, M. Fuse, T. Imagawa, Y. Yamano Nikken Sekkei Ltd. S. Itakura, N. Kumagai, K. Oshima, T. Otsuka RIKEN/SPring-8, Hyogo
	The 700m-long 8 GeV XFEL that was launched by RIKEN is now under construction and will be operational in FY 2010. The strong point of the XFEL facility in Japan is compact under keeping high-performance by applying Spring-8 numerous breakthroughs in accelerator-driven light sources technology. In order to support the high-performance of XFEL, the building was designed with a few architectural ideas. In this paper we introduce the design of building foundation and ground so as to control the transformation of floor which the devices are fixed to, and the design of air conditioning so as to control the temperature change around the devices.

MOPD018	Energy Dependent Measurements of Gamma and Neutron Dose at ANKA	radiation, storage-ring, optics, electron	484
	I. Birkel, E. Huttel, A.-S. Müller, N. J. Smale, P. Wesolowski FZK, Karlsruhe
	Gamma and neutron radiation dose rate around an electron storage ring are proportional to the number of lost particles in a certain time. They are depending on beam energy, current, lifetime and operating conditions of the storage ring. The online area monitoring network of ANKA makes it possible to measure the radiation from the decaying beam at eight stations distributed all over the ANKA hall. Measurements of the ambient dose at beam energies from 800 MeV to 2.5 GeV show higher dose rates around and in the forward direction of insertion devices and other devices with restricted horizontal or vertical aperture.

MOPP008	Design of the Photon Collimators for the ILC Positron Helical Undulator	photon, positron, vacuum, electron	565
	A. Bungau UMAN, Manchester I. R. Bailey, J. B. Dainton, K. M. Hock, L. J. Jenner, L. I. Malysheva Liverpool University, Science Faculty, Liverpool E. Baynham, T. W. Bradshaw, F. S. Carr, J. Rochford STFC/RAL/ASTeC, Chilton, Didcot, Oxon A. J. Brummitt, A. J. Lintern STFC/RAL, Chilton, Didcot, Oxon J. A. Clarke, O. B. Malyshev, N. C. Ryder, D. J. Scott STFC/DL/ASTeC, Daresbury, Warrington, Cheshire N. A. Collomb STFC/DL, Daresbury, Warrington, Cheshire A. F. Hartin OXFORDphysics, Oxford, Oxon S. Hesselbach, G. A. Moortgat-Pick Durham University, Durham L. Zang Cockcroft Institute, Warrington, Cheshire
	A number of photon collimators are placed inside the helical undulator to protect the cold surfaces of the vacuum vessel from being hit by the photons and thus achieving the baseline pressure requirement. Computer simulations were run in order to determine the energy deposition and instantaneous temperature rise in these collimators and various material candidates were studied. This paper presents the status of the simulation.

MOPP023	Test of Short Period SC Undulator	positron, electron, vacuum, radiation	595
	A. A. Mikhailichenko Cornell University, Department of Physics, Ithaca, New York
	We represent details of design and results of test of 4-m long undulator in cryostat having period 12mm and aperture ~6.35 mm allowing K=1.0. This undulator can be used in ILC positron conversion system as well as insertion device for developing FEL systems.

MOPP069	A Prototype Target Wheel for the ILC Positron Source	target, positron, photon, simulation	706
	I. R. Bailey, L. J. Jenner, C. J. Nelson Liverpool University, Science Faculty, Liverpool I. R. Bailey Cockcroft Institute, Warrington, Cheshire D. G. Clarke, K. P. Davies, A. Gallagher STFC/DL, Daresbury, Warrington, Cheshire J. A. Clarke STFC/DL/ASTeC, Daresbury, Warrington, Cheshire J. Gronberg, L. B. Hagler, W. T. Piggott LLNL, Livermore, California
	In this paper we describe the design, construction and commissioning of a prototype based on the positron production target wheel planned for the ILC positron source. The efficiency of the current baseline positron source design for the ILC can be improved if the conversion target is partially immersed in the magnetic field of the capture optics, thereby increasing the overall capture efficiency for positrons by a factor of two or more. However, immersion of the rotating target wheel generates strong eddy currents leading to additional heating and stresses on the wheel. The primary purpose of our prototype, which had been assembled at Daresbury Laboratory, is to investigate the effects of eddy currents induced in a titanium alloy wheel moving with rim speeds up to 100 metres per second in magnetic fields of the order of 1 Tesla.

MOPP070	Construction of a Full Scale Superconducting Undulator Module for the International Linear Collider Positron Source	vacuum, positron, photon, electron	709
	J. A. Clarke, O. B. Malyshev, D. J. Scott, B. J.A. Shepherd STFC/DL/ASTeC, Daresbury, Warrington, Cheshire I. R. Bailey, J. B. Dainton, K. M. Hock, L. J. Jenner, L. I. Malysheva, L. Zang Liverpool University, Science Faculty, Liverpool E. Baynham, T. W. Bradshaw, A. J. Brummitt, F. S. Carr, A. J. Lintern, J. Rochford STFC/RAL, Chilton, Didcot, Oxon A. Bungau UMAN, Manchester N. A. Collomb STFC/DL, Daresbury, Warrington, Cheshire A. F. Hartin OXFORDphysics, Oxford, Oxon S. Hesselbach, G. A. Moortgat-Pick Durham University, Durham Y. Ivanyushenkov ANL, Argonne, Illinois N. C. Ryder University of Bristol, Bristol
	The positron source for the ILC is dependent upon a >200m long undulator to generate a high flux of multi-MeV photons. The undulator system is broken down into a series of 4m cryomodules, which each contain two superconducting helical undulators. Following a dedicated R&D phase and the construction and measurement of a number of short prototypes a full scale cryomodule has now been completed for the first time. This paper reports on the design, manufacture, and test results of this cryomodule.

MOPP072	A Study of Mechanical and Magnetic Issues for a Prototype Positron Source Target	target, simulation, positron, photon	715
	L. J. Jenner, I. R. Bailey Cockcroft Institute, Warrington, Cheshire D. G. Clarke, K. P. Davies, A. Gallagher STFC/DL, Daresbury, Warrington, Cheshire J. A. Clarke STFC/DL/ASTeC, Daresbury, Warrington, Cheshire J. Gronberg, L. B. Hagler, W. T. Piggott LLNL, Livermore, California S. Hesselbach Durham University, Durham C. J. Nelson STFC/RAL, Chilton, Didcot, Oxon J. Rochford STFC/RAL/ASTeC, Chilton, Didcot, Oxon
	In order to construct a high yield, positron source that can meet the intensity requirements of future facilities, a robust conversion target is needed. One solution is to use a rotating titanium alloy wheel upon which a beam of photons is incident. The efficiency of capturing the resulting positrons can be optimised by immersing this system in a magnetic field. As described elsewhere, a prototype of such a target has been built at Daresbury Laboratory, to investigate the mechanical challenges associated with its construction and to study the magnetic effects that the wheel will experience. In this paper, calibration of the instrumentation, the data acquisition system and the initial results from operating the wheel in a strong magnetic field are described. Such phenomena as the eddy current heating experienced by the wheel are measured and compared to results from modelling codes. Vibrational issues surrounding the wheel and supporting structure at various speeds are studied. ID: 3894 A Prototype Target Wheel for the ILC Positron Source

MOPP079	Studies on the Role of a Photon Collimator for the ILC Positron Source	photon, radiation, positron, simulation	733
	L. Zang Cockcroft Institute, Warrington, Cheshire I. R. Bailey, A. Wolski, L. Zang Liverpool University, Science Faculty, Liverpool
	Use of a helical undulator in the ILC positron source provides the possibility of producing a polarised positron beam. The degree of polarisation of the positrons depends upon the polarisation of the photons produced from the undulator, where the polarisation depends on the photon energy and production angle. We calculate these quantities for one design of the helical undulator for the ILC, investigate approximations commonly made in calculating the undulator photon spectrum and explore the role of of a photon collimator in determining the positron polarisation.

TUPC007	Numerical and Experimental Investigation of the Contamination of X-ray Beam Position Monitors by Bending Magnet Edge Radiation	radiation, dipole, synchrotron, photon	1053
	C. Bloomer, G. Rehm, C. A. Thomas Diamond, Oxfordshire
	The details of an investigation into bending magnet edge radiation at Diamond are discussed, reviewing the effects of this radiation on X-ray Beam Position Monitoring (XBPM) equipment. For some time it has been recognized that there are difficulties using XBPMs for determining the centre of mass position of an undulator beam due to contamination from bending magnet radiation. While the geometry of the XBPM blades is designed to help reduce background dipole interference, this radiation is known to account for approximately 1% of the signal received, skewing the calculated beam position by several micrometres. We made detailed models of the bending magnet edge radiation using the SRW program and used Matlab to analyse the data. We present this model and compare our prediction to experimental results obtained at Diamond.

TUPC048	Application of a 5 GSPS Analogue Ring Sampling Chip for Low-cost Single-shot BPM Systems	pick-up, linac, single-bunch, electron	1167
	B. Keil, S. Lehner, S. Ritt PSI, Villigen
	In contrast to storage ring BPMs with continuously sampling ADCs, BPMs of single-bunch linear accelerators with typical repetition rates of 10-100Hz may also use waveform digitisers that sample just during a short interval when the bunch is passing the pickup. At PSI a 12-channel analogue sampling chip called "DRS" has been developed () that samples input signals in an array of 1024 capacitors per channel at up to 5GSPS. The acquisition can be stopped by a trigger signal and then the capacitor voltages of all 12 channels can be digitised with a single commercial external ADC at 33MSPS, achieving ~11 bit effective DC resolution and 450MHz max. bandwidth. The DRS chip was originally developed for low-cost digitization of 3000 detector signals of a particle physics experiment, using the PSI "VPC" VME64x FPGA board as digital back-end equipped with two PMC mezzanine modules with two DRS chips each. However, such DRS-based systems are also an attractive solution for inexpensive direct sampling and FPGA-based post-processing of suitable BPM pickup signals. This paper discusses BPM-related properties, limitations, possible improvements and measurement results of DRS-based electronics. S. Ritt. The DRS chip: Cheap waveform digitizing in the GHz range, Nucl. Instrum. Meth. A518: 470-471, 2004.

TUPC075	Development Status of a Beam Diagnostic System with a Spatial Resolution of Ten Micron-meters for XFEL	electron, radiation, laser, target	1224
	Y. Otake RIKEN Spring-8 Harima, Hyogo H. Ego, H. Tomizawa, K. Yanagida JASRI/SPring-8, Hyogo-ken A. Higashiya, S. I. Inoue, H. Maesaka, T. Shintake, M. Yabashi RIKEN/SPring-8, Hyogo
	Aroud 10 micron-meter stability of an electron beam is required along the undulator section of XFEL to stably generate an X ray laser, and comparable resolution is also required for beam position and size measurements. At SPring-8, the construction of an 8 GeV linac with undulators is now in progress to realize the X ray laser driven by such highly qualified electron beams. To obtain these beams, measurements of the spatial and temporal beam structures are very important. We are developing a beam diagnostic system with a measurement resolution of less than 10 micron-meters. The system comprises a cavity type beam position monitor, an optical transition radiation profile monitor, a beam current monitor, an rf beam deflector to diagnose femto-second order temporal structure, and beam slits to shape appropriately beam spatial structure. The arrangement of these instruments were decided by requirements of the beam position and size measurements based on beam optics design. This paper describes the development status of the beam diagnostic system. The test results and design of the instruments showed sufficient performance to realize the above mentioned measurement resolution.

TUPC077	The 100-MeV Beam Diagnostic Station for the FERMI Linac	laser, diagnostics, electron, emittance	1230
	G. Penco, S. Di Mitri, S. Spampinati ELETTRA, Basovizza, Trieste
	In order to transversally match the beam coming out from the injector to the FERMI@Elettra linac lattice, a beam diagnostic station will be placed at 100 MeV. It is equipped with quadrupoles and Optical Transition Radiation (OTR) screens to measure and correct the beam Twiss parameters and to evaluate the transverse emittances through a three-screen technique. Moreover, the second OTR screen is placed close to the laser heater undulator to guarantee that the eletron/photon interaction is achieved at the beam waist. Design optimization studies and simulation results are presented in this paper.

TUPC110	Bunch Diagnostics with Coherent Infrared Undulator Radiation at FLASH	radiation, electron, diagnostics, background	1320
	A. Willner, H. Delsim-Hashemi, O. Grimm, J. Rossbach Uni HH, Hamburg B. Schmidt DESY, Hamburg
	The operation of the FLASH free electron laser at DESY, Hamburg, requires a high electron beam quality, one important parameter being the longitudinal charge distribution. As a new tool for investigations using coherent radiation techniques, FLASH has been equipped with an electromagnetic undulator. The device is tunable up to a maximum K-Value of 44, corresponding to 200 um wavelength at an electron energy of 500 MeV. The emitted radiation has been characterized in a first measurement campaign using a dispersive spectrometer based on reflective blazed gratings and a pyroelectric detector, operated in a Nitrogen-purged atmosphere. This paper will summarize the measurements and the results obtained from a longitudinal diagnostics analysis.

TUPC114	Results from the Optical Replica Experiments in FLASH	laser, electron, radiation, diagnostics	1332
	V. G. Ziemann, G. Angelova UU/ISV, Uppsala J. Boedewadt, S. Khan, A. Winter Uni HH, Hamburg M. Hamberg, M. Larsson, P. M. Salen, P. van der Meulen FYSIKUM, AlbaNova, Stockholm University, Stockholm F. Loehl, E. Saldin, H. Schlarb, E. Schneidmiller, M. V. Yurkov DESY, Hamburg A. Meseck BESSY GmbH, Berlin
	We present experimental results from the optical replica synthesizer, a novel device to diagnose sub-ps electron bunches by creating a coherent optical pulse in the infrared that has the envelope of the electron bunch and analyzing the latter by frequency resolved optical gating methods. Such a device was recently installed in FLASH at DESY. During an experiment period the spatial and temporal overlap of a several ps long electron bunch and a 200 fs laser pulse were achieved within an undulator. Coherent transition radiation due to the induced micro-bunching was observed on a silver-coated silicon screen and varying the timing between electrons and laser pulse produced two-dimensional images of the slices as a function of the longitudinal position within the electron bunch. In a second experiment the strongly compressed electron bunch is modulated by a laser pulse lengthened to about 2 ps and replica pulses that are emitted from a second undulator are observed and diagnosed by frequency resolved optical gating methods.

TUPP017	Orbit and Dispersion Tool at FLASH	controls, optics, electron, quadrupole	1565
	E. Prat, V. Balandin, N. Golubeva DESY, Hamburg J. K. Kamenik, I. Kriznar, T. Kusterle Cosylab, Ljubljana
	Based on a former MATLAB tool, a java-based application to measure and correct orbit and dispersion has been developed at FLASH. In this paper we discuss the algorithm used in this tool as well as its functionality. First tests on machine operation are also presented.

TUPP018	Impact of Electromagnetic Fields in TESLA RF Modules on Transverse Beam Dynamics	emittance, simulation, electron, free-electron-laser	1568
	E. Prat, W. Decking, M. Dohlus, T. Limberg, I. Zagorodnov DESY, Hamburg
	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.

TUPP022	Measurements of Broad Band Impedance Related Longitudinal Properties of Electron Bunches at DELTA	impedance, single-bunch, synchrotron, klystron	1577
	R. Burek, H. Huck, G. Schmidt, T. Weis, K. Wille DELTA, Dortmund
	DELTA is a 1.5 GeV synchrotron light source which can be operated also at 550 MeV for FEL experiments. Due to interactions with the vacuum chamber, the beam induces wake fields, which act back on the beam and result in a disturbed bunch profile because of potential well distortion and turbulent bunch lengthening. These interactions limit the obtainable bunch length and achievable peak current and therefore strongly affect the FEL-operation. Recent results obtained by streak camera measurements have shown that for short bunches with maximum bunch lengths of 40 ps the longitudinal broad band impedance has to be scaled (SPEAR-scaling) to explain the measurements. The broad band impedance fits well to impedance measurements and calculations performed throughout the last years. The energy spread related to the bunch lengthening has been measured by analysing the undulator spectrum.

TUPP155	Compact EUV Source Based on Laser Compton Scattering between Micro-bunched Electron Beam and CO2 Laser Pulse	laser, electron, scattering, radiation	1869
	S. Kashiwagi, G. Isoyama, R. Kato ISIR, Osaka T. Gowa, A. Masuda, T. Nomoto, K. Sakaue, M. Washio RISE, Tokyo R. Kuroda AIST, Tsukuba, Ibaraki J. Urakawa KEK, Ibaraki
	High-power extreme ultra-violet (EUV) sources are required for next generation semiconductor lithography. We start developing a compact EUV source in the spectral range of 13-14 nm, which is based on laser Compton scattering between a micro-bucnhed electron beam and a high intensity CO2 laser pulse. The electron beam extracted from a DC photocathode gun is micro-bunched using laser modulation techinque and a magnetic compressor before the main laser Compton scattering for EUV radiation. We will describe a considerating scheme for the compact EUV source based on laser Compton scattering with micro-bunched electron beam and the result of its numerical studies. A plan of test experiment generating micro-bunched electron beam will be also introduced in this conference.

TUPP162	High Heat Load Components in TPS Front Ends	synchrotron, radiation, synchrotron-radiation, photon	1890
	A. Sheng, J.-R. Chen, C. K. Kuan, Z.-D. Tsai NSRRC, Hsinchu
	National Synchrotron Radiation Research Center (NSRRC) will build a new synchrotron accelerator (TPS, Taiwan Photon Source) with a great heat-load power. Various IDs have been proposed. For instance, at 3.3 GeV, 350 mA, superconductivity wiggler SW4.8 may generate 5.8mrad wide, 57 kW/mrad² power whereas undulator CU1.8 will be 0.7 mrad, 148 kW/mrad². The function of the fixed mask in TPS front ends not only to protect the downstream vacuum from being hit by the radiation during miss-steering, but also shadow the unwanted power. More than one fixed masks are introduced in some high heat load front ends. High conductivity, high thermomechaical strength GlidCop� is used; design and thermomechanical analysis is also presented in this paper.

WEOBG03	The Design of the Positron Source for the International Linear Collider	positron, target, photon, electron	1915
	J. A. Clarke, O. B. Malyshev, D. J. Scott STFC/DL/ASTeC, Daresbury, Warrington, Cheshire I. R. Bailey, J. B. Dainton, K. M. Hock, L. J. Jenner, L. I. Malysheva, L. Zang Liverpool University, Science Faculty, Liverpool E. Baynham, T. W. Bradshaw, A. J. Brummitt, F. S. Carr, A. J. Lintern, J. Rochford STFC/RAL, Chilton, Didcot, Oxon V. Bharadwaj, J. Sheppard SLAC, Menlo Park, California A. Bungau UMAN, Manchester N. A. Collomb STFC/DL, Daresbury, Warrington, Cheshire R. Dollan Humboldt Universität zu Berlin, Berlin W. Gai, Y. Ivanyushenkov, W. Liu ANL, Argonne, Illinois J. Gronberg, W. T. Piggott LLNL, Livermore, California A. F. Hartin OXFORDphysics, Oxford, Oxon S. Hesselbach, G. A. Moortgat-Pick Durham University, Durham K. Laihem, S. Riemann, A. Schaelicke, A. Ushakov DESY Zeuthen, Zeuthen T. Lohse Humboldt University Berlin, Institut für Physik, Berlin A. A. Mikhailichenko Cornell University, Department of Physics, Ithaca, New York N. C. Ryder University of Bristol, Bristol
	The high luminosity requirements and the option of a polarized positron beam present a great challenge for the positron source of a future linear collider. This paper provides a comprehensive overview of the latest proposed design for the baseline positron source of the International Linear Collider. We report on recent progress and results concerning the main components of the source: including the undulator, collimators, capture optics, and target.
	Slides

WEXM02	Status of the Linac Coherent Light Source	linac, electron, laser, radiation	1939
	J. N. Galayda SLAC, Menlo Park, California
	The Linac Coherent Light Source (LCLS) is a free-electron laser facility in construction at Stanford Linear Accelerator Center. It is designed to operate in the wavelength range 0.15-1.5 nanometers. At the time of this conference, civil construction of new tunnels and buildings is complete, the necessary modifications to the SLAC linac are complete, and the undulator system and x-ray optics/diagnostics are being installed. The electron gun, 135 MeV injector linac and 250 MeV bunch compressor were commissioned in 2007. Accelerator commissioning activities are presently devoted to the achievement of performance goals for the completed linac. R. Akre, et al., "Commissioning the LCLS Injector", submitted to PRSTAB, 2007
	Slides

WEOAM01	Operation Status of the SCSS Test Accelerator: Continuous Saturation of SASE FEL at the Wavelength Range from ~50 to 60 nanometers	electron, laser, emittance, controls	1944
	H. Tanaka, T. Fukui, T. Hara, A. Higashiya, N. Hosoda, T. Inagaki, S. I. Inoue, T. Ishikawa, H. Kitamura, M. K. Kitamura, H. Maesaka, M. Nagasono, T. Ohshima, Y. Otake, T. Sakurai, T. Shintake, K. Shirasawa, T. Tanaka, K. Togawa, M. Yabashi RIKEN/SPring-8, Hyogo T. Asaka, T. Hasegawa, H. Ohashi, S. Takahashi, S. Tanaka JASRI/SPring-8, Hyogo-ken T. Tanikawa RIKEN Spring-8 Harima, Hyogo
	The SPring-8 compact SASE source (SCSS) test accelerator for XFEL/SPring-8 was constructed in 2005. The first lasing at 49 nm, though not reached saturation, was observed with the 250-MeV electron beam in June 2006. Towards the saturation, we started stabilizing the RF system in the injector section, which dramatically stabilized the lasing condition. The stable operation enables us to tune each of the machine parameter precisely by using the lasing response. The second undulator, which did not sufficiently contribute to the first lasing because of large multipole field errors, was replaced by new one. These improvements led us to the successful observation of SASE saturation at the wavelength ranging from ~50 to 60 nm in September 2007. A pulse-energy of 30 uJ is routinely obtained at 60 nm. Analysis of the obtained SASE saturation data with a 3D-FEL simulation code, SIMPLEX, suggests that the electron beam emittance is almost unchanged through the bunch compression process. The stable and intense EUV SASE FEL has been offered for user experiments since October 2007. The achieved electron beam performance, lasing property as well as the latest analysis result will be presented.
	Slides

WEOAM02	A Scheme for Stabilization of Output Power of an X-ray SASE FEL	laser, radiation, linac, electron	1947
	E. Schneidmiller, G. Geloni, E. Saldin, M. V. Yurkov DESY, Hamburg
	Stability of XFEL radiation is naturally linked to stability of the linac RF system through bunch compression, leading to very tight requirements on RF amplitude and phase. We propose a new scheme that allows to relax these requirements by a large factor.
	Slides

WEPC010	Upgrade of the ESRF Accelerator Complex	insertion, insertion-device, storage-ring, lattice	2004
	P. Elleaume, J. C. Biasci, J-F. B. Bouteille, J. M. Chaize, J. Chavanne, L. Farvacque, L. Goirand, M. Hahn, L. Hardy, J. Jacob, R. Kersevan, J. M. Koch, J. M. Mercier, A. Panzarella, C. Penel, T. P. Perron, E. Plouviez, E. Rabeuf, J.-L. Revol, A. Ropert, K. B. Scheidt, D. Schmied, V. Serriere ESRF, Grenoble
	The ESRF, the first third generation synchrotron radiation source, opened its first beamline in 1994 and has been continuously developed since then to satisfy the user community. However, the need arose to make a major upgrade of the infrastructure and accelerator complex in order to fulfil the request for new scientific applications. The experimental Hall will be expanded and half of the beamlines reconstructed. The storage ring lattice will be modified to provide space for longer as well as a larger number of insertion devices. New insertion devices will be developed possibly based on in-vacuum permanent magnets at cryogenic temperature. The electron beam positioning system will be rebuilt to provide a higher photon beam stability. The RF system will face a major reconstruction with a new type of RF transmitters and HOM damped cavities allowing stable operation at a ring current of 300 mA without feedback. The injector system will be upgraded to operate the 16 and 4 bunch fillings in the top-up mode in order to increase the average current and obtain a higher photon beam stability. ESRF Science and Technology Programme, 2008-2017.

WEPC016	Operation Status and Performances Upgrade on SOLEIL Storage Ring	feedback, vacuum, photon, insertion	2022
	J.-M. Filhol, J. C. Besson, F. Bouvet, P. Brunelle, L. Cassinari, M.-E. Couprie, J.-C. Denard, C. Herbeaux, J.-F. Lamarre, J.-P. Lavieville, P. Lebasque, M.-P. Level, A. Loulergue, P. Marchand, A. Nadji, L. S. Nadolski, R. Nagaoka, M.-A. Tordeux SOLEIL, Gif-sur-Yvette
	SOLEIL is the French 2.75 GeV third generation synchrotron light source delivering beam to users since January 2007. Beginning of 2008 up to 13 beam-lines are taking beam, 7 from insertion devices (IDs), 2 from IR ports, and 4 from dipole ports, and 6 of them are open to external Users. Users have a full control of their IDs. With a 300 mA stored beam current in multi-bunch filling pattern, and position stability in the few micron range, the main target performances have been reached. A beam of 50 mA in 8 bunches was delivered to users for the first time in December 2007 for time structure experiments. Operation and performance status will first be given, namely subsystem behaviour (RF, vacuum, �), beam optics, orbit stability, beam lifetime, and operation statistics. Then the main objectives for 2008 will be reviewed: delivery of 4000 hours of user beam time, installation and commissioning of a second cryomodule for reaching the 500 mA current target, construction and installation of 6 new IDs leading to a total number of 17, improvement of the orbit stability with a fast orbit feedback complementary to the slow orbit one, and preparation for top-up operation.

WEPC022	Operation and Recent Developments at the ESRF	feedback, storage-ring, lattice, cryogenics	2028
	J.-L. Revol, J. C. Biasci, J-F. B. Bouteille, J. M. Chaize, J. Chavanne, P. Elleaume, L. Farvacque, G. Gautier, L. Goirand, M. Hahn, L. Hardy, J. Jacob, R. Kersevan, J. M. Koch, J. M. Mercier, I. Parat, C. Penel, T. P. Perron, E. Plouviez, A. Ropert, K. B. Scheidt, D. Schmied, V. Serriere ESRF, Grenoble
	The ESRF has been operating for a period close to fifteen years and is now looking towards an ambitious upgrade programme for the coming ten years. This paper reports on the performances achieved today with the ESRF storage ring, as well as developments accomplished and projects underway. These include a new filling mode for pump and probe experiments, the evolution of insertion devices, developments to improve beam stability, in particular transverse and longitudinal multibunch feedbacks, and the current increase from 200 to 300 mA. The upgrade of the lattice to accommodate longer straight sections and the new High Quality Power Supply system will also be presented. The machine reliability and the most important failures will be discussed. Finally, the use of an electronic logbook in routine operation will be presented, and the status on the control system including TANGO collaboration given.

WEPC023	Ideas for a Future PEP Light Source	brightness, emittance, photon, storage-ring	2031
	R. O. Hettel, K. L.F. Bane, L. D. Bentson, K. J. Bertsche, S. M. Brennan, Y. Cai, A. Chao, S. DeBarger, V. A. Dolgashev, X. Huang, Z. Huang, D. Kharakh, Y. Nosochkov, T. Rabedeau, J. A. Safranek, J. Seeman, J. Stohr, G. V. Stupakov, S. G. Tantawi, L. Wang, M.-H. Wang, U. Wienands SLAC, Menlo Park, California I. Lindau Stanford University, Stanford, Califormia C. Pellegrini UCLA, Los Angeles, California
	With the termination of operation of the PEP-II storage rings for high energy physics at hand, and with the migration of accelerator operation at SLAC in general to photon science applications, a study of the potential conversion of the PEP-II to a future light source has been initiated. With a circumference of 2.2 km and the capability for high current operation, it is clear that operating a converted ring at medium energy (3-6 GeV) could offer very low emittance and an average brightness of order 10²², limited primarily by the power handling capacity of photon beam line optical components. Higher brightness in the soft X-ray regime might be reached with partial lasing in long undulators if the emittance is sufficiently low, and high peak brightness could be reached with seeded FEL emission. Advanced pulsed rf technology might be used to generate short bunches and fast switched polarization in soft X-ray rf undulators. An overview of the preliminary findings of the PEP Light Source study group will be presented, including lattice, X-ray source and beam line options.

WEPC028	Status of UVSOR-II and Light Source Developments	laser, electron, radiation, injection	2046
	M. Katoh, M. Adachi, K. Hayashi, M. Shimada, J. Yamazaki UVSOR, Okazaki M. Hosaka, Y. Takashima, N. Yamamoto Nagoya University, Nagoya A. Mochihashi JASRI/SPring-8, Hyogo-ken
	UVSOR, a 750 MeV synchrotron light source of 53m circumference had been operated for more than 20 years. After a major upgrade in 2003, this machine was renamed to be UVSOR-II. The ring is now routinely operated with low emittance of 27 nm-rad and with four undulators. Top up injection is under preparation. The ring is equipped with a resonator type free electron laser. The shortest wave length has reached 200nm. Several user experiments in the deep UV region are in progress. Coherent terahertz synchrotron radiation and coherent harmonic generation are extensively studied by using an ultra-short laser system, under international collaborations. An upgrade plan of the ring is under consideration to improve the experimental setup of the light source developments.

WEPC034	Present Status of Siam Photon Source	storage-ring, photon, injection, synchrotron	2061
	P. Klysubun, S. Cheedket, G. G. Hoyes, M. Oyamada, W. Pairsuwan, S. Rugmai, P. Sudmuang NSRC, Nakhon Ratchasima
	The Siam Photon Source (SPS) is a 1.2 GeV synchrotron light source situated in Nakhon Ratchasima, Thailand. It is currently in the fourth year of routine operation for synchrotron radiation users. In order to address the increasing user demand for increasing beamtime, better beam position stability, and improved machine reliability, several machine improvements and upgrades have been undertaken during the past year. This report first briefly gives the overview and important parameters of the light source, and then describes the current operation status and operation statistics in 2007. Recent machine improvements, for instance, modernization of injector components, improvement of vacuum system, recalibration of beam position monitors, and orbit correction, are presented together with the initial synopsis of the successful installation of the first insertion device, a permanent magnet planar undulator.

WEPC035	Present Status of PF-ring and PF-AR in KEK	injection, insertion, insertion-device, photon	2064
	Y. Kobayashi, S. Asaoka, K. Ebihara, K. Haga, K. Harada, T. Honda, T. Ieiri, M. Izawa, T. Kageyama, T. Kasuga, M. Kikuchi, K. Kudo, H. Maezawa, K. Marutsuka, A. Mishina, T. Mitsuhashi, T. Miyajima, H. Miyauchi, S. Nagahashi, T. T. Nakamura, T. Nogami, T. Obina, K. Oide, M. Ono, T. Ozaki, C. O. Pak, H. Sakai, Y. Sakamoto, S. Sakanaka, H. Sasaki, Y. Sato, M. Shimada, T. Shioya, M. Tadano, T. Tahara, T. Takahashi, S. Takasaki, Y. Tanimoto, M. Tejima, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, S. Yamamoto, Ma. Yoshida, M. Yoshimoto KEK, Ibaraki
	In KEK, we have two synchrotron light sources which were constructed in the early 1980s. One is the Photon Factory storage ring (PF-ring) and the other is the Photon Factory advanced ring (PF-AR). The PF-ring is usually operated at 2.5 GeV and sometimes ramped up to 3.0 GeV to provide photons with the energy from VUV to hard X-ray region. The PF-AR is mostly operated in a single-bunch mode of 6.5GeV to provide pulsed hard X-rays. Operational performances of them have been upgraded through several reinforcements. After the reconstruction of the straight section of the PF-ring in 2005, two short-period-gap undulators have been stably operated. They allow us to produce higher brilliant hard X-rays even at the energy of 2.5 GeV. In March 2008, the circular polarized undulator will be installed in the long straight section of 8.9 m. In the PF-AR, new tandem undulators have been operated since September 2006 to generate much stronger pulsed hard X-rays for the sub-ns resolved X-ray diffraction experiments. In this conference, we report present status of the PF-ring and the PF-AR.

WEPC048	Experimental Characterization of the Insertion Device Effects on Beam Dynamics at SOLEIL	focusing, injection, coupling, insertion	2097
	P. Brunelle, C. Benabderrahmane, F. Briquez, O. V. Chubar, O. Marcouillé, F. Marteau, A. Nadji, L. S. Nadolski SOLEIL, Gif-sur-Yvette
	SOLEIL, the French 2.75 GeV third generation light source, has been delivering photons to beam lines in routine operation since January 2007. The storage ring is presently equipped with eleven insertion devices: 3 in-vacuum 20mm period undulators (U20), 1 Apple-II type 52mm period undulator (HU52), 3 Apple-II type 80mm period undulators (HU80), 3 electromagnetic 256mm period undulators (HU256) and 1 electromagnetic 640mm period 10m long undulator (HU640). Commissioning of insertion devices consists of characterizing all the effects on beam dynamics in terms of focussing, injection efficiency, beam lifetime and sensitivity to working point, and also in optimizing feedforward tables in order to compensate for closed orbit distortions during field variations (this last point is detailed in other papers). We will focus here on the significant effects observed with some undulators. Measurements, using electron beam, of the transverse variation of field integrals, were helpful to understand bad effects impacting the daily operation. The introduction of real magnetic characteristics in the lattice model is in progress in order to further optimize the working point.

WEPC073	Layout of the Beam Switchyard at the European XFEL	kicker, septum, linac, collimation	2163
	W. Decking, F. Obier DESY, Hamburg
	A unique feature of the European XFEL will be the possibility to distribute electron bunches of one beam pulse to different FEL beam lines. This is achieved by using a combination of fast kickers and a DC septum. Integration of a beam abortion dump allows a flexible selection of the bunch pattern at the FEL experiment, while the superconducting linear accelerator operates with constant beam-loading. We describe the principal scheme, the geometrical and optical layout and deal with stability and technical issues like the fast kicker development.

WEPC075	Recent Results and Future Perspectives of the SPARC Project	emittance, linac, laser, radiation	2169
	M. Ferrario, D. Alesini, M. Bellaveglia, R. Boni, M. Boscolo, M. Castellano, E. Chiadroni, A. Clozza, L. Cultrera, G. Di Pirro, A. Drago, A. Esposito, L. Ficcadenti, D. Filippetto, V. Fusco, A. Gallo, G. Gatti, A. Ghigo, B. Marchetti, A. Marinelli, C. Marrelli, E. Pace, L. Palumbo, L. Pellegrino, R. Ricci, U. Rotundo, C. Sanelli, F. Sgamma, B. Spataro, F. Tazzioli, S. Tomassini, C. Vaccarezza, M. Vescovi, C. Vicario INFN/LNF, Frascati (Roma) A. Bacci, I. Boscolo, F. Broggi, F. Castelli, S. Cialdi, C. De Martinis, D. Giove, C. Maroli, V. Petrillo, A. R. Rossi, L. Serafini INFN-Milano, Milano M. Bougeard, B. Carré, D. Garzella, M. Labat, G. Lambert, H. Merdji, P. Salieres, O. Tchebakoff CEA, Gif-sur-Yvette L. Catani INFN-Roma II, Roma A. Cianchi Università di Roma II Tor Vergata, Roma F. Ciocci, G. Dattoli, A. Dipace, A. Doria, G. P. Gallerano, L. Giannessi, E. Giovenale, G. L. Orlandi, S. Pagnutti, A. Petralia, M. Quattromini, C. Ronsivalle, E. Sabia, I. P. Spassovsky, V. Surrenti ENEA C. R. Frascati, Frascati (Roma) M.-E. Couprie SOLEIL, Gif-sur-Yvette M. Mattioli, M. Serluca INFN-Roma, Roma M. Migliorati, A. Mostacci Rome University La Sapienza, Roma M. Petrarca Università di Roma I La Sapienza, Roma J. B. Rosenzweig UCLA, Los Angeles, California
	The SPARC project foresees the realization of a high brightness photo-injector to produce a 150-200 MeV electron beam to drive 500 nm FEL experiments in various configurations, a Thomson backscattering source and a plasma accelerator experiment. The SPARC photoinjector is also the test facility for the recently approved VUV FEL project named SPARX. As a first stage of the commissioning a complete characterization of the photoinjector has been accomplished with a detailed study of the emittance compensation process downstream the gun-solenoid system and the demonstration of the emittance oscillation in the drift. The second stage of the commissioning, that is currently underway, foresees a detailed analysis of the beam matching with the linac in order to confirm the theoretically prediction of emittance compensation based on the “invariant envelope” matching and the demonstration of the “velocity bunching” technique in the linac. In this paper we report the experimental results obtained so far and the scientific program for the near future.

WEPC096	APPLE Undulator for PETRA III	dipole, polarization, emittance, radiation	2219
	J. Bahrdt, H.-J. Baecker, W. Frentrup, A. Gaupp, M. Scheer, B. Schulz BESSY GmbH, Berlin U. Englisch, M. Tischer DESY, Hamburg
	Currently, the storage ring PETRA is being rebuilt to a light source with an ultra low emittance of only 1nm rad. The undulator radiation will take full advantage of this high performance. PETRA III will also provide circularly polarized light and linearly polarized light under arbitrary angles (inclined mode) within the energy range of 250-3000eV. The light will be produced with an APPLE II undulator which is under construction at BESSY at present. The total length of 5m and a minimum gap of only 11mm cause strong 3D forces. Due to the small good field region in an APPLE undulator and a small stay clear between the magnets and the vacuum chamber a sophisticated mechanical layout is required. The design will be presented, the expected residual mechanical deformations will be given and the consequences for the spectral performance will be discussed.

WEPC097	Active Shimming of the Dynamic Multipoles of the BESSY UE112 APPLE Undulator	multipole, injection, electron, dynamic-aperture	2222
	J. Bahrdt, W. Frentrup, A. Gaupp, M. Scheer, G. Wuestefeld BESSY GmbH, Berlin
	APPLE undulators produce strong dynamic multipoles in the elliptical and inclined mode which can significantly reduce the electron beam dynamic aperture. The multipole strength scales with the square of the period length and the inverse of the electron energy. A large horizontal dynamic aperture is essential for top up operation. For the BESSY devices the dynamic multipoles generated in the elliptical mode have efficiently been compensated with iron shims. For the inclined mode no passive compensation scheme is available. In case of the strong BESSY 112mm APPLE device flat current wires have been glued onto the undulator chamber, which permit the cancellation of arbitrary multipoles. The full horizontal dynamic aperture has been recovered in the inclined mode. Tracking simulations and measurements of the electron beam performance for uncompensated and compensated dynamic multipoles will be presented.

WEPC098	Development of Cryogenic Undulator CPMU at SOLEIL	permanent-magnet, vacuum, cryogenics, radiation	2225
	C. Benabderrahmane, P. Berteaud, N. Béchu, M.-E. Couprie, J.-M. Filhol, C. Herbeaux, C. A. Kitegi, J. L. Marlats, A. Mary, K. Tavakoli SOLEIL, Gif-sur-Yvette
	On SOLEIL at 2.75 GeV, producing hard X rays requires short period and small gap in-vacuum hybrid permanent magnet undulators. Besides, higher achieved peak magnetic field can be while operating at cryogenic temperature Tc (around 140 K). When cooling down the permanent magnets, the remanence Br increases down to a certain temperature at which the process is limited by the appearance of the Spin Reorientation Transition phenomenon. The coercivity is also increased at Tc which improves significantly the resistance to radiation. R&D studies, aims at replacing SmCo by NdFeB permanent magnets whose Br of 1.4 T, could enable to increase at least by 30% the peak magnetic field at Tc. Unfortunately such magnet grade can’t be heated to high temperature without degrading the magnetic properties, which limits the residual pressure that can be achieved. Temperature gradient and mechanical deformation are also technical issues. Different permanent magnet grades at Tc are characterized. Studies are also carried out on a small assembly of four periods. Residual pressures obtained with or without partial baking on standard U20 in-vacuum undulators are compared.

WEPC099	A Superconductive Undulator for the Munich Laser-plasma Accelerator	electron, radiation, photon, brilliance	2228
	P. Peiffer, T. Baumbach, A. Bernhard, D. Wollmann University of Karlsruhe, Karlsruhe F. J. Gruener, D. Habs, C. Huebsch, R. Weingartner LMU, München R. Rossmanith FZK, Karlsruhe
	Laser-plasma accelerators are expected to produce electron beams with bunch charges in the nano-Coulomb range with energies in the GeV range. By employing short-period superconductive undulators this may be utilized for the generation of undulator radiation in the X-ray regime with a compact laboratory-sized set up. In this contribution we report on the project of testing this concept at the Laser-Plasma Accelerator in Munich. A particular aim of this project is to push the superconductive undulator technology to shortest periods and highest on-axis fields at gap widths sufficiently large to reduce the impact of resistive wall wake fields on the electron beam. This might open a path to the generation of coherent radiation via the SASE process.

WEPC100	Superconducting Insertion Devices with Variable Period Length	wiggler, photon, brilliance, insertion	2231
	A. Bernhard, T. Baumbach, P. Peiffer, D. Wollmann University of Karlsruhe, Karlsruhe R. Rossmanith FZK, Karlsruhe
	The tuning range and functionality of superconducting insertion devices may be significantly enhanced by period length switching. Period length switching can be achieved by employing two or more individually powerable subsets of superconducting coils in such a way that a current reversal in a part of these coil sets results in a period length variation. In this paper the opportunities and restrictions of period length switching in superconducting undulators are discussed from a general point of view. As a particular example, the design of a hybrid superconducting undulator/wiggler (SCUW) for ANKA based upon the period length switching technique is presented.

WEPC101	Improved Homogeneity of Permanent Magnets for Undulators and Wigglers	permanent-magnet, wiggler, controls, alignment	2234
	F.-J. Boergermann, R. Blank, G. W. Reppel Vacuumschmelze GmbH & Co. KG, Hanau J. Bahrdt BESSY GmbH, Berlin J. Pflueger DESY, Hamburg
	The homogeneity of permanent magnets for use in undulators and wigglers were significantly improved in close collaboration between industry and scientific institutes throughout the last three years. Magnets with a variation of less than ± 1% in remanence, ± 1° magnetic angle and ± 1% hot/cold-side effect can be produced now - a variation of the magnetic angle of less than ± 0.5 ° is possible for some products. The development was assisted by improved characterization equipment for magnetic dipole moment and magnetic inhomogeneities by the scientific partners, which was made available for industrial application at Vacuumschmelze.

WEPC102	Commissioning of the Electromagnetic Insertion Devices at SOLEIL	radiation, power-supply, insertion, insertion-device	2237
	F. Briquez, P. Brunelle, O. V. Chubar, M.-E. Couprie, J.-M. Filhol, O. Marcouillé, F. Marteau, A. Nadji, L. S. Nadolski, M. Valleau, J. Vétéran SOLEIL, Gif-sur-Yvette
	SOLEIL is the French 2.75 GeV third generation synchrotron radiation light source. Eleven undulators are installed yet in the storage ring and nineteen more Insertion Devices (ID) will be installed on the ring by January 2010. Among the installed IDs, there are four electromagnetic undulators of two different designs: one 640 mm period air coils undulator called HU640 and three 256 mm period undulators called HU256, made up of independent H yoke dipoles. The HU640 provides photons in any polarisation from linear to elliptical, in a range extending from 5 to 40 eV, thanks to three different groups of coils powered independently. The HU256, which are subject to hysteresis, provide horizontal and vertical, periodic or quasi-periodic linear polarisations, and also circular polarisation, covering a total range from 10 eV to 1 keV. The effects of each undulator on the closed orbit have been extensive studied, and compensated, using dedicated embedded steering coils. The correction method will be explained and its results will be shown and compared to the magnetic measurements. Finally, the first measurements of the radiation produced will be shown and compared to previsions.

WEPC105	Construction of a Cryogenic Permanent Magnet Undulator at ESRF	cryogenics, vacuum, simulation, laser	2243
	J. Chavanne, M. Hahn, R. Kersevan, C. A. Kitegi, C. Penel, F. Revol ESRF, Grenoble
	A cryogenic permanent magnet undulator (CPMU) has been constructed at ESRF. The device is a full scale in-vacuum undulator with a magnetic length of 2 metres and a period of 18 mm. This prototype is still compatible with an operation at room temperature, it has been mainly used to investigate the technological issues connected to the operation at low temperature. An important effort has been dedicated to the construction of a complete measuring bench operated in-vacuum with the undulator at cryogenic temperatures around 150 K. The bench includes a stretched wire system for field integral measurement and a local field measurement assembly suitable for the accurate characterization of the optical phase error along the undulator. The main results of the magnetic measurements will be presented , they confirm the simulations performed with RADIA using NdFeB permanent magnet material models at low temperature. The cryogenic system used to cool the undulator is based on a reliable liquid nitrogen closed loop. The heat budget of the device will be discussed. The prototype has been installed on the ESRF ring in December 2007. The first results of operation will be presented.

WEPC106	Compensation of Variable Skew- and Normal quadrupole Focusing Effects of APPLE-II Undulators with Computer-aided Shimming	quadrupole, radiation, insertion, insertion-device	2246
	O. V. Chubar, F. Briquez, M.-E. Couprie, J.-M. Filhol, E. Leroy, F. Marteau, F. Paulin, O. Rudenko SOLEIL, Gif-sur-Yvette
	Variable (phase- and gap-dependent) skew- and normal-quadrupole focusing effects of APPLE II undulators on electron beam are reportedly complicating practical use of this type of insertion devices in many synchrotron radiation sources. We show that these undesirable effects, whatever their "origin", can be well controlled and in many cases efficiently compensated during the standard "virtual" shimming of APPLE-II undulators. Our method exploits small variations of the skew- and normal-quadrupole focusing components resulting from extra magnetic interaction, introduced by displacements of permanent magnet blocks during the shimming procedure, at different undulator phase and gap values. These variations can be calculated to a high accuracy, included into the corresponding "shim signatures" of magnetic field integrals, and used, along with undulator magnetic measurements data, for calculation of the most efficient magnet displacements. This approach is well suited for a computer-aided (e.g., genetic optimization based) shimming procedure. Practical results obtained with several APPLE-II undulators, which are currently successfully operating on the SOLEIL storage ring, are presented.

WEPC107	Observation and Interpretation of Dynamic Focusing Effects Introduced by APPLE-II Undulators on Electron Beam at SOLEIL	electron, focusing, betatron, storage-ring	2249
	O. V. Chubar, P. Brunelle, M.-E. Couprie, J.-M. Filhol, A. Nadji, L. S. Nadolski SOLEIL, Gif-sur-Yvette
	The paper presents the results of electron beam closed orbit distortion (COD) and tune shift measurements performed on three different APPLE-II type undulators when making horizontal displacements of the electron beam orbit in those straight sections of the SOLEIL storage ring where these undulators are installed. In agreement with data from other storage rings, our results show that, when APPLE-II undulators are used in elliptical, linear-vertical or linear-tilted polarization modes, the measured tune shifts and the COD can not be explained only by residual first-order focusing effects: taking into account the second-order, or dynamic focusing effects, is necessary. We describe a COD interpretation method allowing for straightforward comparison of the measured effects on electron beam with the corresponding predictions from calculations and magnetic measurements. The observed dynamic effects are in good agreement with calculations performed using RADIA code. We also discuss possible modification of the figures of merit to be used at computer-aided shimming of APPLE-II undulators, which would allow for simultaneous minimization of the first- and second-order focusing effects.

WEPC108	Portable Magnetic Field Measurement System	controls, laser, vacuum, feedback	2252
	J. Kulesza, A. Deyhim, E. Van Every, D. J. Waterman Advanced Design Consulting, Inc, Lansing, New York K. I. Blomqvist MAX-lab, Lund
	This portable magnetic field measurement system is a very sophisticated and sensitive machine for the measurement of magnetic fields in undulators (Planer, EPU, and Apple II), wigglers, and in-vacuum ID units. The magnetic fields are measured using 3 axis hall-effect probes, mounted orthogonally to a thin wand. The wand is mounted to a carriage that rides on vacuum air bearings. The base is granite. A flip coil is provided on two vertical towers with X, Y and Theta axes. Special software is provided to assist in homing, movement, and data collection.

WEPC109	Development of an In-vacuum Undulator System for U-SAXS Beamline at PLS	controls, vacuum, monitoring, ion	2255
	D. J. Waterman, A. Deyhim, J. Kulesza, E. Van Every Advanced Design Consulting, Inc, Lansing, New York K. I. Blomqvist MAX-lab, Lund
	The design of a hybrid in-vacuum undulator with 20mm period, effective peak field of 1.05 Tesla, and 1800 mm magnetic length is being presented. The design requirements and mechanical difficulties for holding, positioning, and driving the magnetic arrays are explored. The structural and finite element analysis, magnetic design, and electrical considerations that influenced the design are then analyzed. This in-vacuum undulator (IVUN) is being installed at Pohang Accelerator Laboratory (PAL) for U-SAXS (Ultra Small Angle X-ray Scattering) beamline. The IVUN will generate undulator radiation up to ~14 keV using higher harmonic (upto 9th) undulator radiation with 2.5 GeV PLS electron beam.

WEPC111	Latest Progress in Insertion Devices at ACCEL Instruments	insertion, insertion-device, alignment, synchrotron	2261
	D. Doelling, B. Fischer, A. Hobl, P. A. Komorowski, D. Krischel, M. Meyer-Reumers, H. Vogel ACCEL, Bergisch Gladbach
	ACCEL Instruments GmbH has designed, manufactured, and tested several insertion devices for synchrotron light sources and free electron lasers around the world. ACCEL has been awarded for the construction of two In – Vacuum – Undulators for the ALBA/CELLS synchrotron light source in Barcelona, Spain. The design originates from the standard ESRF IVU based on the license agreement with their ID group. The status of the design work will be summarized. Also ACCEL is manufacturing two granite measurement benches for the FERMI project at Elettra in Trieste, Italy. Both benches are designed to characterize insertion devices in a fast and accurate way. A summary of the commissioning results will be presented. A full functional prototype Hybrid Undulator for the European X-FEL project in Hamburg was delivered successfully and, as the first device, in full compliance with the technical specification. Also the industrial study requested by DESY for the adaptation of the design towards a large series production of 5m long undulators for the European X-FEL, was completed as the first one in full compliance with the DESY specification and the basic conclusions are presented.

WEPC113	Heat Load Issues of Superconducting Undulator Operated at TPS Storage Ring	radiation, storage-ring, synchrotron, synchrotron-radiation	2267
	C.-S. Hwang, J. C. Jan, P. H. Lin NSRRC, Hsinchu
	The superconducting undulator with periodic length of 1.5 cm and magnet gap of 5.6 mm has been studied. The magnetic flux density of 1.4 T has been achieved. However, the heat loads from image current of the electron in the storage ring and the synchrotron radiation from bending magnet are the critical issues. The calculated power from the image current and the synchrotron radiation of bending magnet are about 3.5 W/m and 1.7 W, respectively. The superconducting undulator will be operated at the 3 GeV TPS storage ring that the operation current and the magnet flux density of dipole magnet is 400 mA and 1.19 T, respectively. The superconducting RF cavity will be installed in the TPS such that the bunch length is only 2.8 mm. Hence, the superconducting Landau cavity is necessary to extend the bunch length for reducing the heat load on the beam duct. In addition, some strategies are needed to be studied to avoid the synchrotron radiation heating on the 4.2 K vacuum chamber. The soft-end dipole design and the chicane mechanism are studied to solve the issue herein.

WEPC114	Improved Winding of Superconducting Undulator and Measurement of Quenching Tolerance	radiation, synchrotron, synchrotron-radiation, storage-ring	2270
	J. C. Jan, C.-H. Chang, C.-S. Hwang, F.-Y. Lin NSRRC, Hsinchu
	The superconducting (SC) wire windings of the mini-pole superconducting undulator at National Synchrotron Radiation Research Center (NSRRC) have an improved performance. A precise measurement of the magnetic field was undertaken to examine the quality of the wire winding. We improved the insulation between wires and the iron pole to avoid SC wire degradation when the coil was trained up to high current. A Teflon coating (layer thickness 0.035-0.045 mm) on the iron pole is capable of providing insulation to 0.5 kV. We pasted extra Teflon tape (thickness 0.12 mm) on the coating layer; this Teflon tape serves as a buffer that avoids the SC wires scraping the Teflon coating layer during adjustment of the position of the SC wire during winding. A quenching experiment was also performed to detect the heat tolerance of the SC wires during extra heating of the beam duct; a heating tape (Ni80Cr20) simulated the heating of the beam duct by synchrotron radiation. The SC wires and heater are separated by the stainless steel (SS) beam duct (thickness 0.3 mm) and an epoxy layer (thickness 0.1 mm). This result is an important issue in cryostat design.

WEPC115	Development of IVUN at Pohang Accelerator Laboratory	radiation, vacuum, electron, insertion-device	2273
	D. E. Kim, H. S. Han, Y. G. Jung, C. K. Kim, H.-G. Lee, S. H. Nam, P. C.D. Park, K.-H. Park, H. S. Suh PAL, Pohang, Kyungbuk
	Pohang Accelerator Laboratory (PAL) is developing In Vacuum Undulator (IVUN). A short magnetic length (about 1.0 m) IVUN with 24 mm magnetic period will be developed first and a longer IVUN with 1.8 m magnetic length which will be installed in the PLS storage ring will follow. The IVUN will be equipped with built-in magnetic measurement system to ensure the accuracy of the assembly, any degradation coming from the radiation damage or high temperature. Basically, a hall probe system will be installed with linear guide to translate the measurement assembly. In this report, the design issues related to the vacuum system, measurement system, and other engineering problems of the IVUN will be discussed.

WEPC116	FERMI@Elettra Undulator Frame Study	polarization, alignment, simulation	2276
	D. La Civita, R. Bracco, B. Diviacco, G. Tomasin, D. Zangrando ELETTRA, Basovizza, Trieste
	The FERMI@Elettra project foresees installation of both linear (LPU) and elliptical polarization undulators (EPU). Following the girder study presented last year, a detailed design of the undulator frame has been now carried out. The aim of this work was to find out a mechanical structure that guarantees minimum displacement of the girders supporting the magnet arrays. At the same time the undulator overall dimensions have been taken into account and the mechanical structure mass minimized. In this paper topology optimization result, finite element simulation and multi-objective optimization analysis are presented.

WEPC117	Influence of Insertion Devices on the ALBA Dynamic Aperture	wiggler, lattice, dynamic-aperture, betatron	2279
	E. B. Levichev, P. A. Piminov BINP SB RAS, Novosibirsk D. Einfeld ALBA, Bellaterra
	Insertion devices can produce effects reducing the dynamic aperture in a storage ring. To study these effects for the ALBA light source the following insertion devices were inserted in the ALBA lattice: a superconducting wiggler SC-W31 with 31-mm-period and 2.1-T-field amplitude, and two Apple-II type PMM NdFeB undulators with periods of 62 mm (HU62) and 71 mm (HU71). Results of numerical study of the nonlinear beam dynamics by a 6D computer code are presented.

WEPC118	Study of Controllable Polarization SASE FEL by a Crossed-planar Undulator	polarization, radiation, electron, simulation	2282
	B. Faatz, Y. Li, J. Pflueger, E. Saldin, E. Schneidmiller, M. V. Yurkov DESY, Hamburg
	A potential and economical access to generate arbitrary polarized XFEL is to utilize crossed-undulator scheme instead of helical undulators. In this paper, the polarization of x-ray radiation for the European XFEL is investigated. The degree of polarization and the Stokes parameters are calculated for different configurations. The shot-to-shot fluctuation of polarization and the degree of polarization distribution over the transverse plane are also studied.

WEPC119	First Year's Experience of Diamond Insertion Devices	injection, photon, wiggler, insertion	2285
	E. C. Longhi, R. T. Fielder, I. P.S. Martin, J. C. Schouten, B. Singh Diamond, Oxfordshire R. Bartolini JAI, Oxford
	Diamond was commissioned at 3GeV with seven insertion devices (IDs) already installed. The phase 1 IDs include five in-vacuum permanent magnet undulators, an APPLE–2 variable polarization device, and a superconducting wiggler. Since initial commissioning of the ring, three more in-vacuum undulators have been installed, and another three devices will be installed in the coming year. In this paper, we describe commissioning, characterizing, and operating with these IDs.

WEPC121	Magnetic Measurement Device for Superconductive Undulator Mock-up Coils at ANKA	vacuum, synchrotron, electron, superconductivity	2291
	E. M. Mashkina, B. K. Kostka, E. Steffens University of Erlangen-Nürnberg, Physikalisches Institut II, Erlangen T. Baumbach, A. Bernhard, D. Wollmann University of Karlsruhe, Karlsruhe S. Casalbuoni, A. W. Grau, M. Hagelstein, R. Rossmanith FZK, Karlsruhe
	A device for precise magnetic measurements of superconductive coils was designed, built and installed at the synchrotron radiation source ANKA, Forschungszentrum Karlsruhe. Accurate magnetic field measurements are a prerequisite for the characterization and optimization of insertion devices. The new device allows measuring the magnetic field magnitude of test coils with a longitudinal precision of 10 μm using a 2D Hall probe bench. The cylindrical liquid He cryostat allows mounting coils of maximum dimensions 50 cm in length and 30 cm in diameter. The set-up is computer controlled. The contribution will present the new device as well as the results obtained.

WEPC122	Magnetic Characterization of an APPLE-II Undulator Prototype for FERMI@Elettra	quadrupole, sextupole, controls, multipole	2294
	B. Diviacco, R. Bracco, C. Knapic, D. La Civita, D. Millo, M. Musardo, G. Tomasin, D. Zangrando ELETTRA, Basovizza, Trieste
	The FERMI@Elettra free electron lasers will use APPLE-II undulators in the radiating sections to provide variably polarized photon beams. In preparation of the manufacturing of the final devices a prototype has been developed in order to test different methods of magnetic field optimization. For this purpose, an existing variable-gap support structure was equipped with a new mechanical interface providing the required longitudinal shifting of the magnetic arrays. Permanent magnet blocks were mounted on short modules and their field integrals measured using a stretched wire system. Field optimization was iteratively performed by proper selection of the modules to be mounted based on measurements of the partially assembled undulator structure. The results of the final magnetic field characterization are presented showing the achieved trajectory, phase and multipole errors. These results are compared with those of a previous assembly where the same modules were mounted in random order. Further improvements obtained by shimming and application of “magic fingers” are finally described.

WEPC124	Magnetic Measurement System for the SPARC Insertion Devices	laser, controls, alignment, electron	2297
	M. Quattromini, F. Ciocci, G. Dattoli, M. Del Franco, A. Doria, G. P. Gallerano, L. Giannessi, E. Giovenale, A. Lo Bue, G. L. Orlandi, A. Petralia, P. Rossi, L. Semeraro, I. P. Spassovsky, V. Surrenti ENEA C. R. Frascati, Frascati (Roma) A. Dipace, E. Sabia ENEA Portici, Portici (Napoli)
	The characteristics and performances of the magnetic measurement system for the SPARC insertion devices are presented. A typical configuration formed by a a Hall probe mounted on a cart sliding on a granite beam was adopted to measure the properties of the six SPARC undulator sections. This approach has been adopted usually for rapid local field measurements. In this contribution we show that precision levels comparable to those of other well established techniques can be achieved also for critical issues like alignments, field integrals, phase errors etc. A new device purposedly designed to identify the reading area of the Hall probe with respect to bench coordinate system is presented and discussed.

WEPC125	Development of Three New Superconducting Insertion Devices for the ANKA Storage Ring	wiggler, synchrotron, insertion, insertion-device	2300
	R. Rossmanith, S. Casalbuoni, A. W. Grau, M. Hagelstein FZK, Karlsruhe T. Baumbach, A. Bernhard, P. Peiffer, D. Wollmann University of Karlsruhe, Karlsruhe C. Boffo, M. Borlein, W. Walter BNG, Würzburg B. K. Kostka, E. M. Mashkina, E. Steffens University of Erlangen-Nürnberg, Physikalisches Institut II, Erlangen
	After a first successful test of a superconductive cold bore undulator in ANKA a new generation of superconductive insertion devices is under construction or in a detailed planning phase. The first one, referred to as as SCU14 and now under construction, is an improved version of the existing undulator (14 mm period length, 100 periods long) with a new cooling scheme for small gap operation and a reduced field error. The period length of the second device called SCUW can be switched electrically between 15 and 45 mm. The third one is a superconductive undulator which can tolerate a beam heat load of several Watts in combination with a small field error named SCU2. It is designed for third generation light sources with a heat load of up to 6 Watt from the beam to the cold bore.

WEPC126	On a Biscuit Current Undulator	electron, laser, wiggler, radiation	2303
	S. Sandru UPG, Ploiesti V. Babin INOE, Bucharest M. R. Leonovici Bucharest University, Faculty of Physics, Bucharest-Magurele V. I.R. Niculescu INFLPR, Bucharest - Magurele
	A new undulator structure for free electron lasers was presented. Current BISCUIT devices produce magnetic fields which are spatially periodic. The current structure was in the shape of wires stacks . The current has alternating directions. The magnetic field components for each wire presents symmetry with two axis. The BISCUIT undulator transverse cross-section (in arbitrary units) is a function depending directly on cosine (for x component) and sine (for y component) and inverse on the square root of the sum of forth power of sine and cosine. The z component is a constant. The Biot - Savart law was numerically evaluated. The magnetic field is longitudinal and easily adjustable with the current. The versatility of the constant parameter covers longitudinal undulator or wiggler design for one or two beams devices with transverse momenta.

WEPC128	SPUR: A New Code for the Calculation of Synchrotron Radiation from Very Long Undulator Systems	radiation, electron, synchrotron, synchrotron-radiation	2305
	N. C. Ryder, D. J. Scott STFC/DL/ASTeC, Daresbury, Warrington, Cheshire S. Reiche UCLA, Los Angeles, California
	The accurate calculation of synchrotron radiation from an undulator is a common problem and numerous codes have been developed that describe analytic and measured fields. However, for very long undulator systems, comprising of many individual modules and total lengths in excess of 100s of meters, for example as found in the LCLS, X-FEL, the ILC positron source undulator systems, there is not a suitable code that can handle the amount of data in a convenient manner and which runs in a practically realisable time limit. The development of a new code, SPontaneous Undulator Radiation, SPUR, is presented which computes the spontaneous radiation from electron beams passing through a system of undulators. The code supports parallel architecture, and uses the HDF5 technology to efficiently handle the multi-dimensional data. The latest results developments and benchmarking are presented.

WEPC129	Undulator Demagnetization due to Radiation Losses at FLASH	radiation, quadrupole, free-electron-laser, permanent-magnet	2308
	J. Skupin, B. Faatz, Y. Li, J. Pflueger, T. Vielitz DESY, Hamburg
	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 510^-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 210^-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.

WEPC130	Shimming Correction of Dynamic Multipole Effects on Apple-II Type EPUs at the ALS	multipole, polarization, injection, simulation	2311
	C. Steier, A. Madur, S. Marks, S. Prestemon, T. Scarvie, D. Schlueter, W. Wan LBNL, Berkeley, California
	Elliptically Polarizing Undulators that provide full photon polarization control also have fast, intrinsic transverse roll-off of the magnetic field. The roll-off is particularly fast for vertical polarization settings, and can have big detrimental effects on the nonlinear single particle dynamics. Particularly low and medium energy light sources and long period EPUs are prone to those effects. The three existing 50mm period EPUs at the ALS have been retrofitted with shims to correct for these dynamic multipole effects and a new 90mm period device which otherwise would have caused a huge reduction in dynamic aperture has been shimmed before installation. Simulations and beam measurements will be presented, including frequency map measurements.

WEPC131	Insertion Devices for NSLS-II Baseline and Future	insertion, insertion-device, wiggler, electron	2314
	T. Tanabe RIKEN/RARF/CC, Saitama J. Bengtsson, D. A. Harder, S. L. Kramer, G. Rakowsky, J. Rank BNL, Upton, New York
	NSLS-II is going to employ Damping Wigglers not only for emittance reduction but also as broadband hard X-ray source. In-Vacuum Undulators with minimum RMS phase error (< 2 degree) and possible cryo-capability are planned for X-ray planar device, and Elliptically Polarized Undulators are utilized for polarization controls. Due to lack of hard X-ray flux from weak dipole field (0.4 Tesla), three pole wigglers of peak field over 1 Tesla will be mainly used by NSLS bending magnet beam line users. Magnetic designs and kick maps for dynamic aperture surveys were created using the latest version of Radia for Mathematica 6 which we supported the development. There are other devices planned for later stage of the project, such as quasi-periodic EPU, superconducting wiggler/undulator, and Cryo-Permanent Magnet Undulator with Praseodymium Iron Boron (PrFeB) magnets and textured Dysprosium poles. For R&D, Hybrid PrFeB arrays were assembled and field measured at room temperature, liquid nitrogen and liquid helium temperature using our vertical test facility. We have also developed a specialized power supply for pulsed wire measurement.

WEPC133	Status of the PETRA III Insertion Devices	controls, insertion, multipole, insertion-device	2320
	M. Tischer, M. Barthelmess, U. Englisch, J. Pflueger, A. Schoeps, J. Skupin DESY, Hamburg
	The PETRA storage ring is presently reconstructed towards a third generation light source. In total, 14 undulator beamlines will be available in the new octant of the machine. We report on the status of Petra III undulators. Three prototypes with 29mm period length, two 2m and one 5m long device have been investigated by mechanical and magnetic measurements. The prototype results are the basis for the refined design of the remaining 8 planar devices which are in the procurement phase. We present preliminary magnetic results of the prototypes and also report on the APPLE–2 and the in-vacuum undulator for PETRA III.

WEPC135	A New Concept for Reducing Phase Errors in Superconductive Undulators: Induction-shimming	permanent-magnet, electron, photon, simulation	2323
	D. Wollmann, T. Baumbach, A. Bernhard, P. Peiffer University of Karlsruhe, Karlsruhe R. Rossmanith FZK, Karlsruhe
	Undulators are the most advanced sources for the generation of synchrotron radiation. The photons generated by a single electron add up coherently along the electron trajectory. In order to do so the oscillatory motion of the electron has to be in phase with the emitted photons along the whole undulator. Small magnetic errors can cause unwanted destructive interferences. In standard permanent magnet undulators the magnetic errors are reduced by applying shimming techniques. Superconductive undulators have higher magnetic fields than permanent magnet undulators but shimming is more complex. In this paper it is shown that coupled superconductive loops installed along the surface of the superconductive undulator coil can significantly reduce the destructive effect of the field errors. This new idea might allow the building of undulators with a superior field quality.

WEPC136	Waveguide Structures for RF Undulators with Applications to FELs and Storage Rings	radiation, electron, polarization, storage-ring	2326
	M. Yeddulla, H. G. Geng, Z. Huang, Z. Ma, S. G. Tantawi SLAC, Menlo Park, California
	RF undulators, suggested long time ago, has the advantage of fast dynamic control of polarization, undulator strength and wavelength. However, RF undulators require very strong RF fields in order to produce radiation of the same order as conventional static devices. Very high power RF energy confined inside a waveguide or a cavity can provide the necessary RF fields to undulate the electron beam. However, the wall losses in the waveguide should be low enough to make it practically feasible as a CW or quasi CW undulator and, hence, competitive with static devices for applications to storage rings and FELs. Here we present various waveguide structures such as smooth walled and corrugated walled waveguides and various RF modes. We will show that there are some advantages in operating with higher order modes and also with hybrid modes in the corrugated guide. We will show that the RF power requirement for some of these modes will permit a quasi CW operation of the undulator, thus permitting its operation in a storage ring.

WEPC137	Design of Two Variable Polarization Undulators for the ALBA Project	controls, polarization, beam-losses, power-supply	2329
	D. Zangrando, R. Bracco, B. Diviacco, D. La Civita, M. Musardo, G. Tomasin ELETTRA, Basovizza, Trieste F. Becheri, J. Campmany, C. Colldelram, D. Einfeld, J. V. Gigante ALBA, Bellaterra Z. Martí LLS, Bellaterra (Cerdanyola del Vallès)
	This paper summarizes the main aspects of the magnetic, mechanical and control system design of two APPLE-II type undulators presently under construction in the framework of a collaboration between CELLS and Sincrotrone Trieste.

WEPC143	System for Local Magnetic Field Measurement System Based on a Coil with Three Square Millimeter	multipole, alignment, impedance	2344
	J. F. Citadini, R. Basilio, M. Potye, G. Tosin LNLS, Campinas
	We present a magnetic field measurement system based on a rotating coil with 3mm2 active area and approximately 500 turns to measure local magnetic field. The structure of a coil is not so complex, simplifying the evaluation of its sources of errors. The steps used to build the coil are shown as well as the performance of the measurement system. The calibration of the coil was made against a magnetic field generated by a solenoid with very well determined geometry.

WEPC150	Fast Local Bump System for Helicity Switching at the Photon Factory	photon, vacuum, kicker, alignment	2356
	K. Harada, Y. Kobayashi, T. Miyajima, S. Nagahashi, T. Obina KEK, Ibaraki S. Matsuba Hiroshima University, Graduate School of Science, Higashi-Hiroshima
	Two APPLE-II type variably polarizing undulators will be installed at the south straight section of the PF (Photon Factory) ring. The 10Hz fast orbit switching in these undulators will be conducted for the helicity switching. The required angular difference of the orbits in two undulators is 0.3mrad. The five identical bump magnets and AC power supplies are manufactured to make 10Hz time varying local bumps. In order to achieve the local bump and prevent the fluctuation of the beam orbit with the effects of the insertion devices and magnetic errors, the feed forward correction with the bump magnets and the feedback correction with the fast steering magnets are required. In this presentation, the measurement results of the magnetic field and the frequency response, the configuration of the control system, and the simulation results to achieve the local bumps are shown.

WEPC152	Magnet Block Optimization of the APPLE-II Elliptically Polarized Undulator	polarization, radiation, synchrotron, synchrotron-radiation	2362
	T. Wang, Q. K. Jia USTC/NSRL, Hefei, Anhui
	The uniform field region of elliptically polarized undulator (EPU) of APPLE-II type is very short especially in the horizonta axis. The magnet block arrangements with a approximately parabolic pole face or of APPLE-II undulator can enlarge the horizontal field roll-off and shorten the vertical field roll-off. We studied the dfferent shapes to expect a optimizaed horizotal and vertical field roll-off.

WEPD003	Manufacture and Test of a Small Ceramic-insulated Nb3Sn Split Solenoid	collider, damping, vacuum, linear-collider	2404
	B. Bordini, R. Maccaferri, L. Rossi, D. Tommasini CERN, Geneva
	A small split solenoid wound with high Jc Nb3Sn conductor, constituted by a 0.8 mm Rod Re-stack Process (RRP) strand, was built and tested at CERN in order to study the applicability of: ceramic wet glass braid insulation without epoxy impregnation of the magnet; a new heat treatment devised at CERN and particularly suitable for reacting RRP Nb3Sn strands. This paper briefly describes the solenoid and the experimental results obtained during 4.4 K and 1.9 K tests. The split solenoid consists of two coils (25 mm inner diameter, 51.1 mm outer diameter, 12.9 mm height). The coils were initially separately tested, in an iron mirror configuration, and then tested together in split solenoid configuration. In all the tests at 4.4 K the coils reached a current higher than 97% of their short sample limits at the first quench; in split solenoid configuration the maximum field in the coils and in the aperture were respectively 10.7 T and 12.5 T. At 1.9 K the coils had premature quenches due to self field instability despite the rather high RRR of the two coils (190 and 270). This phenomenon at 1.9 K, expected by our theory* and also confirmed by strand measurements, is discussed. *B. Bordini, E. Barzi, S. Feher, L. Rossi, and A. V. Zlobin. "Self-Field Effects in Magneto-Thermal Instabilities for Nb-Sn Strands," to be published in IEEE Trans. Appl. Supercond. 2008.

WEPP077	The XFEL Laser Heater	laser, electron, gun, vacuum	2695
	V. G. Ziemann, G. Angelova UU/ISV, Uppsala M. Dohlus, Y. A. Kot DESY, Hamburg
	The high-brilliance photo-cathode gun foreseen for the X-FEL will provide beams with extremely small momentum spread that will make the beam susceptible to micro-bunching instabilities which will spoil SASE operation. It is therefore desirable to increase the momentum spread to a level that prevents these instabilties but still is compatible with SASE operation. The laser heater will achive this by superimposing a transversely polarized laser and the electron beam in a properly tuned undulator, thereby producing a momentum modulation that is smeared out in a dogleg chicane to obtain the desired momentum spread increase. We present the initial design and layout of the laser heater system for the X-FEL in Hamburg.

WEPP157	Lithium Lens for Positron Production System	positron, target, optics, focusing	2856
	A. A. Mikhailichenko Cornell University, Department of Physics, Ithaca, New York
	We represent optimized parameters for undulator-based positron production scheme for ILC-type machine. In particular we describe details of Lithium lens design suggested for usage in collection optics.

THPC072	Impact of Betatron Motion on Path Lengthening and Momentum Aperture in a Storage Ring	betatron, storage-ring, optics, resonance	3152
	M. Takao JASRI/SPring-8, Hyogo-ken
	The amplitude of the betatron motion in an electron storage ring becomes large in some cases, e.g. Touschek scattered electrons or injected beam. Then we cannot ignore the effect of a finite amplitude of betatron motion on the beam dynamics. The path lengthening of the central trajectory of betatron motion is one of the most serious manifestations of such an influence. Due to the synchrotron motion, the variation of the path length is converted into the energy deviation, so that the betatron motion gives the impact on the momentum aperture in the storage ring. In this paper the path lengthening by a finite amplitude betatron motion is calculated by means of the canonical perturbation method. The derived formula for the path lengthening is simply represented by the product of the chromaticity and the invariant amplitude. Using the formula, we discuss the impact of the betatron motion on momentum aperture in a Touschek effect.

THPC123	The PSI DSP Carrier (PDC) Board - a Digital Back-end for Bunch-to-bunch and Global Orbit Feedbacks in Linear Accelerators and Storage Rings	feedback, controls, kicker, storage-ring	3272
	B. Keil, R. Kramert, G. Marinkovic, P. Pollet, M. Roggli PSI, Villigen
	PSI has developed a signal processing VXS/VME64x board for accelerator applications like low-latency bunch-to-bunch feedbacks, global orbit feedbacks or low-level RF systems. The board is a joint development of PSI/SLS staff and staff working on the contribution of PSI for the European X-ray FEL (E-XFEL). Future applications of the board include the Intra-Bunchtrain Feedback (IBFB) of the E-XFEL as well as the upgrade of the SLS Fast Orbit Feedback (FOFB) and Multibunch Feedback (MBFB). The PDC board has four Virtex-4 FPGAs, two TS201 Tiger Sharc DSPs, VXS and VME64x 2eSST interfaces, and two front panel SFP multi-gigabit fibre optic links. Two 500-pin LVDS/multi-gigabit mezzanine connectors allow to interface the FPGAs to two application-dependent mezzanine modules each containing e.g. four 500 Msps 12-bit ADCs and two 14-bit DACs for the IBFB and MBFB, or four multi-gigabit SFP fibre optic transceivers for the FOFB. This paper reports on hardware and firmware concepts, system topologies and synergies of future applications.

THPC146	Beam Halo Monitor Using Diamond Detectors for XFEL/SPring-8	electron, induction, radiation, permanent-magnet	3330
	H. Aoyagi, Y. Asano, T. Bizen, K. Fukami, N. Nariyama JASRI/SPring-8, Hyogo-ken T. Itoga, H. Kitamura, T. Tanaka RIKEN/SPring-8, Hyogo
	The construction of the XFEL facility at SPring-8 has been started. We have been developing a halo monitor as an interlock device for protection of undulator permanent magnets against radiation damage. When permanent magnets are irradiated with a halo part of 8GeV electron beam, magnetic fields are degraded permanently and laser oscillation is weakened. Therefore, the interlock device is required during machine operation. Diamond detector, which operates in photoconductive mode, is good candidate for electron beam sensor. The beam test of the diamond detector head has been carried out at the beam dump of the SPring-8 booster synchrotron. Minimum number of injected electron was about 1·10⁵ /pulse, and we observed the pulse height of 0.1V having the pulse length of 0.6nsec FWHM without a preamplifier. The linearity of output signal on injected beam was also demonstrated. The beam halo monitor equipped with the diamond detectors is under manufacturing. The design and feasibility tests will be presented in this conference.

THPC157	A Simple Method for Timing an XFEL Source to High-power Lasers	electron, radiation, photon, laser	3357
	G. Geloni, E. Saldin, E. Schneidmiller, M. V. Yurkov DESY, Hamburg
	We propose a technique for timing an XFEL to a high-power laser with femtosecond accuracy. The same electron bunch is used to produce an XFEL pulse and an ultrashort optical pulse that are, thus, naturally synchronized. Cross-correlation techniques will yield the relative jitter between the optical pulse (and, thus, the XFEL pulse) and a pulse from an external pump-laser with femtosecond resolution. Technical realization will be based on an optical replica synthesizer (ORS) setup to be installed after the final bunch-compressor. The electron bunch is modulated in the ORS by an external optical laser. Travelling through the main undulator, it produces the XFEL pulse. Then, a powerful optical pulse of coherent edge radiation is generated as the bunch passes through a long straight section and a separation magnet downstream of the main undulator. Relative synchronization of these pulses is preserved using the same mechanical support for X-ray and optical elements transporting radiation to the experimental area, where single-shot cross-correlation between optical pulse and pump-laser pulse is performed. We illustrate our technique with numerical examples referring to the European XFEL.

THPP040	Choice of Accelerating System for Undulator Linear Accelerator	simulation, ion, linac, rfq	3455
	E. S. Masunov, N. V. Avreline, V. S. Dyubkov, S. M. Polozov MEPhI, Moscow A. L. Sitnikov ITEP, Moscow
	The undulator linear accelerators (UNDULAC) were suggested as a new type of high intensity low energy ion linac. Such accelerators can be realized in periodical IH structure. The RF field in UNDULAC has no spatial harmonics in synchronism with the beam. An accelerating force is to be driven by a combination of two non-synchronous space harmonics. The ratio of first to zero RF field harmonics amplitude must be equal to 0.25-0.4. The effective beam bunching and focusing could be provided in this case. The construction of UNDULAC accelerating channel is discussed to realize such ratio. The first results of IH resonator type choice are also presented. E. S. Masunov, Technical Physics, V. 46, 11, 2001, pp. 1433-1436.

THPP137	Development of Vacuum Components for XFEL/SPring-8	vacuum, ion, target, cathode	3682
	T. Bizen RIKEN/SPring-8, Hyogo
	Several new vacuum components have been developed for the XFEL/SPring-8 project. Vacuum waveguide flanges for C-band and S-band were successfully developed. These flanges provide both RF seal and vacuum seal. This seal mechanism can make vacuum seal even with a scratched gasket. A solid-lubricated clean bolt was developed for C-band and S-band flanges to avoid organic dust pollution that induce multipactor. New vacuum flange for accelerator beam line can use three types of gasket. A small RF contact for 28 mm inside diameter bellows was developed. This unfixed RF contact can move freely in all directions and displaced large.

THPP145	Machine Operation Issues Related to the Vacuum System of the ESRF	vacuum, cryogenics, storage-ring, beam-losses	3705
	R. Kersevan, M. Hahn, I. Parat, D. Schmied ESRF, Grenoble
	This paper deals with various operational issues related to the vacuum system of the ESRF storage ring. The impact on the vacuum pressure, beam lifetime, beam losses and other machine parameters after installation of new chambers, diagnostics, RF cavities and insertion devices, and vacuum leaks is discussed in some detail. Particular emphasis is given to the behaviour of the prototype of a 2m-long cryogenic in-vacuum undulator, a new RF cavity, and NEG-coated chambers. Lessons learned from the operation of these and other vacuum components will be extended to the proposed machine upgrade.