EPAC08 - List of Keywords (laser)

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laser

Paper	Title	Other Keywords	Page
MOYAGM01	Review of DESY FEL Activities	radiation, electron, undulator, 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

MOZBM01	High Intensity and Low Emittance Guns	gun, electron, cathode, emittance	46
	P. M. Michelato INFN/LASA, Segrate (MI)
	High intensity or high-brilliance, low emittance electron beams are needed for many applications, ranging from SASE FELs to fast radiolysis systems, from Compton backscattering X ray sources to energy recovery linac, from CW FELs to the linear collider. They are produced using a high field RF accelerating structure together with a photoemissive electron source: the rapid acceleration process minimizes the space charge effects which tend to spoil the emitted beam characteristics. The talk will review the technology and provide the important parameters of these sources as the generated bunch charge, the repetition rate, the mean and peak current, the beam emittance, etc, together with an analysis of gun reliability and technological challenges. I will present the state of the art of the technology of the RF guns, either using metallic or semiconductor photoemitters. New high repetition rate/CW sources, appearing in the last years, using superconducting cavities, will be also reviewed.
	Slides

MOPC001	The Status of TAC Infrared Free Electron Laser (IR-FEL) Facility	undulator, electron, linac, 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, undulator, radiation	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	undulator, electron, simulation, bunching	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)

MOPC004	First Results from the Upgraded PITZ Facility	gun, diagnostics, electron, cathode	70
	J. W. Baehr, S. Lederer DESY, Hamburg G. Asova INRNE, Sofia C. H. Boulware, H.-J. Grabosch, M. Hänel, Ye. Ivanisenko, S. Khodyachykh, S. A. Korepanov, M. Krasilnikov, B. Petrosyan, S. Rimjaem, T. A. Scholz, R. Spesyvtsev, L. Staykov, F. Stephan DESY Zeuthen, Zeuthen L. Hakobyan YerPhI, Yerevan R. Richter BESSY GmbH, Berlin J. Roensch Uni HH, Hamburg K. Rosbach Humboldt University Berlin, Institut für Physik, Berlin A. Shapovalov MEPhI, Moscow
	During autumn and winter 2007 a general reconstruction of the PITZ facility was performed. A new spectrometer based on a dipole magnet with 180 degree deflection angle was inserted in the facility. The new spectrometer contains two screen stations for the measuring of the longitudinal phase space and the slice emittance. A new "Conditioning Test Stand" (CTS) was added to the facility. Using this CTS a new electron gun having an improved cooling system is under conditioning. A new photocathode laser system (developed by MBI) was installed and commissioned. The goal is to reach rise and fall times of the laser pulses of 2 ps. The system of laser diagnostic was upgraded. The results reached using this upgraded facility are reported. This concerns the conditioning results of the new gun. Furthermore, a gun will be characterised using the new diagnostics beamline and the new photocathode laser. Results of the commissioning and first measurements of the new diagnostics components will be reported.

MOPC005	The ARC-EN-CIEL Radiation Sources	radiation, undulator, electron, 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.

MOPC006	Seeding of the Test FEL at MAX-lab	electron, gun, alignment, linac	76
	N. Cutic, F. Curbis, F. Lindau, S. Thorin, S. Werin MAX-lab, Lund
	The test FEL at MAX-lab has recently been completed. The system will be seeded at 263 nm by a tripled Ti:sapphire laser synchronized to the RF system and the gun laser. Issues important for the seeding will be presented, ranging from the laser system via the layout of photon and electron optics to timing/synchronization and the theoretical approach. Experimental results on the seeding operation will also be presented.

MOPC007	Status and Upgrade Program of the FERMI@ELETTRA Linac	linac, gun, klystron, controls	79
	G. D'Auria, A. O. Borga, S. Di Mitri, O. Ferrando, G. C. Pappas, A. Rohlev, A. Rubino, C. Serpico, M. Trovo, A. Turchet, D. Wang ELETTRA, Basovizza, Trieste
	FERMI@ELETTRA is a seeded FEL user facility under construction at Sincrotrone Trieste, Italy. It will use the existing normal conducting S-band linac and with the installation of seven accelerating sections received from CERN after the LIL decommissioning, will be operated at 1.2 GeV. After the successful commissioning of the new injector system of ELETTRA, the linac has been disconnected from the storage ring and now is being revised and upgraded with the installation of new important subsystems, i.e., a new photoinjector, bunch compressors, laser heater, additional accelerating structures, etc. Here a description of the upgrade program as well as the ongoing activities on the main parts of the machine are reported and discussed.

MOPC011	Improvement and Recent Results of the DELTA Storage Ring FEL	electron, alignment, undulator, 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.

MOPC017	Operation of the UVSOR-II CHG-FEL in Helical Configuration	undulator, 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	undulator, 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.

MOPC023	ARC-EN-CIEL Beam Dynamics	emittance, brightness, gun, space-charge	115
	A. Loulergue, M.-E. Couprie SOLEIL, Gif-sur-Yvette C. Bruni LAL, Orsay
	ARC-EN-CIEL project is based on a CW 1.3 GHz superconducting linac accelerator delivering high charge, subpicosecond and low emittance electron bunches at high repetition rate. According to the electron energy, it provides tunable light source of high brightness in the VUV to soft X-ray wavelength domain. The project will evolve into three phases: first and second phases are based on high brightness single pass SC linac configuration with a low average current (few μA), while third phase comports recirculation loops to increase the average current (up to 100 mA). This paper deals with electron beam dynamics issues for the single pass configuration in the two first phases from the RF gun to undulators including magnetic compression stages. In the ERL configuration of the third phase, the accelerator scheme and focusing are investigated in order to take into account collective effects as Beam Break Up instability.

MOPC026	Status of SPARX Project	undulator, radiation, electron, linac	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.

MOPC027	A Fast Switching Mirror Chamber for FLASH	feedback, radiation, electron, controls	124
	S. Pauliuk, U. Gensch, R. Heller, M. Sachwitz, H. Thom, D. Thürmann DESY Zeuthen, Zeuthen U. Hahn, S. Karstensen, H. Schulte-Schrepping, K. I. Tiedtke DESY, Hamburg
	Switching mirrors are used to provide several beamlines with FEL or synchrotron radiation from one source. Since most users do not need the nominal pulse density, this is a method to supply many experimental groups. So far, the switching process has a duration of several minutes. A study at DESY Zeuthen analyzes the possibility and accuracy of permanent switching, e.g. at half the FEL's pulse frequency of 1 to 10 Hz. A prototype satisfying highest demands on repetition accuracy of the position (below 1 μm) and yawing (about 1 arcsec) is being tested. In the course of the work many technical concepts from industry like PLC or Position-Velocity Streaming found their way into beamline technology, allowing fast proceedings in development.

MOPC028	Experimental Layout of 30 nm High Harmonic Laser Seeding at FLASH	electron, undulator, radiation, 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.

MOPC030	Operation of FLASH at 6.5 nm Wavelength	radiation, gun, electron, linac	133
	S. Schreiber, B. Faatz, K. Honkavaara DESY, Hamburg
	FLASH, the Free-Electron-Laser at DESY, Germany has been upgraded in 2007. A 6th accelerating module with eight 9-cell superconducting cavities of the TESLA type has been installed. In addition, another module has been replaced and the tuners of a third module have been repaired. In September 2007, a beam energy of 1 GeV has been achieved for the first time, followed by lasing at 6.5 nm shortly after. With this remarkable achievement, the initial design goals of the FEL in terms of beam energy and wavelength have been reached.

MOPC032	Progress of the Commissioning of the Test FEL at MAX-lab	gun, simulation, electron, emittance	139
	S. Thorin, F. Curbis, N. Cutic, F. Lindau, S. Werin MAX-lab, Lund M. Abo-Bakr, J. Bahrdt, K. Holldack BESSY GmbH, Berlin
	In a collaboration between MAX-lab and BESSY a seeded Harmonic Generation Free Electron Laser is being constructed at MAX-lab. The setup uses the existing MAX-lab facility together with a Ti:Sa 266 nm lasersytem used for both the gun and seeding and an optical klystron consisting of a modulator, a chicane and a radiator. The different parts of the system has been installed and commissioning with electrons of the full setup started during the fall of 2007. In this paper the progress of the commissioning of the Test FEL and our initial results are presented.

MOPC034	Collective Effects in a Short-Pulse FEL Driver	emittance, linac, electron, space-charge	145
	P. H. Williams, H. L. Owen STFC/DL/ASTeC, Daresbury, Warrington, Cheshire G. Bassi Cockcroft Institute, Warrington, Cheshire S. Thorin MAX-lab, Lund
	There is much interest in the provision of coherent, tunable VUV and soft X-ray pulses of duration less than 10fs. A 1.3 GHz linac driver concept has been developed, and in this paper we address collective effects in the short electron bunches using start-to-end modelling. In particular, we examine the limitations from coherent radiation and induced microbunching, and their impact on the design of the accelerator system.

MOPC035	PULSE - A High-Repetition-Rate Linac Driver for X-ray FELs	electron, emittance, gun, undulator	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.

MOPC036	Pancakes versus Beer-cans in Terms of 6D Phase-space Density	emittance, simulation, electron, cathode	151
	S. B. van der Geer, O. J. Luiten, M. J. de Loos TUE, Eindhoven S. B. van der Geer Pulsar Physics, Eindhoven
	Uniformly filled ellipsoidal (waterbag) electron bunches can be created in practice by space charge blow out of transversely tailored ‘pancake’ bunches. Ellipsoidal bunches have linear self fields in all dimensions, and will not deteriorate in quality under linear transport and acceleration. There is a discussion if such a bunch is better than a conventional beer-can shape. This paper compares the two approaches in terms of usable phase-space density. Detailed GPT simulations of a simplified setup show that although the pancakes approach requires less charge, it is the application that is decisive. O. J. Luiten et al. Phys. Rev. Lett. Vol 93, 094802 (2004).

MOPC038	Ultra-high Brightness Electron Beams by All-optical Plasma-based Injectors	plasma, electron, undulator, 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.

MOPC040	COBALD - an Inverse Compton Back-scattering Source at Daresbury	electron, photon, vacuum, beam-transport	160
	D. J. Holder STFC/DL/ASTeC, Daresbury, Warrington, Cheshire D. Laundy STFC/DL, Daresbury, Warrington, Cheshire G. Priebe STFC/DL/SRD, Daresbury, Warrington, Cheshire
	An inverse Compton Back-scattering (CBS) ultra-short pulsed x-ray source driven by the multi-terawatt laser installed at Daresbury’s Energy Recovery Linac Prototype (ERLP) is being developed. Hard x-rays, ranging from 15 keV to 30 keV, depending on the backscattering geometry, will be generated through the interaction of the laser pulse and an electron bunch delivered by ERLP. The X-rays created contain 15 ·10⁶ photons per pulse from head-on collisions, with a pulse duration comparable to that of the incoming electron bunch, and 5 ·10⁶ photons per pulse from side-on collisions, where the laser pulse defines the pulse width. The peak spectral brightness of ≈10²⁰ photons/s/mm²/mrad²/0.1% ΔE/E is close to that of 4th-generation synchrotron light sources. Called COBALD, it will initially be used as a short pulse diagnostic for the ERLP electron beam and will explore the extreme challenges of photon/electron beam synchronization, which is a fundamental requirement for all accelerator-based (whether FEL or spontaneous SR) dynamics programmes. Furthermore, a fast-melting experiment will be used as a diagnostic tool to provide further information on the stability of the source.

MOPC041	Microfabrication of Relativistic Electron Beam by Laser and its Application to THz Coherent Synchrotron Radiation	electron, radiation, storage-ring, synchrotron	163
	M. Katoh, M. Adachi, S. I. Kimura, A. Mochihashi, M. Shimada UVSOR, Okazaki S. Bielawski, C. Evain, C. Szwaj PhLAM/CERCLA, Villeneuve d'Ascq Cedex T. Hara RIKEN Spring-8 Harima, Hyogo M. Hosaka, Y. Takashima, N. Yamamoto Nagoya University, Nagoya T. Takahashi KURRI, Osaka
	It is well known that broadband coherent synchrotron radiation (CSR) is emitted by an electron bunch whose length is shorter than radiation wavelength. However, even a long electron bunch can emit CSR when it has micro-density structure whose characteristic length is equal to the radiation wavelength. Recently, we have demonstrated that, by injecting amplitude modulated laser pulses into an electron storage ring, quasi-monochromatic and tunable terahertz (THz) CSR could be produced. In this method, periodic micro-density structure of THz scale was created on the electron bunch, as the result of the laser-electron interaction. The bunch emitted quasi-monochromatic THz radiation in a uniform dipole filed, not in an undulator. This new technology provides a way to imprint periodic wave patterns inside the electron bunch phase space. In adding to the light source applications, this would be a new tool to investigate electron beam dynamics.

MOPC043	Design of LINAC Based Compact X-ray Source via Inverse Compton Scattering at Waseda University	electron, acceleration	166
	A. Masuda, T. Gowa, C. Igarashi, T. Kashino, N. Mitsuda, K. Sakaue, M. Washio RISE, Tokyo H. Hayano, J. Urakawa KEK, Ibaraki S. Kashiwagi ISIR, Osaka R. Kuroda AIST, Tsukuba, Ibaraki K. U. Ushida RIKEN, Saitama
	A table-top size soft X-ray source based on inverse Compton scattering has been developed at Waseda University. We have already succeeded in generating X-rays via inverse Compton scattering between 4.6 MeV electron beam generated from a photocathode RF-gun and 1047nm Nd:YLF laser. The energy of the X-ray is within the 'water window' region which can be applied for the soft X-ray microscope for biological observation. In 2007, new RF-gun cavity with Cs-Te photocathode in place of copper has been installed. The energy of electron beam became up to 5.5MeV due to the increase of Q-value of the gun cavity. According to this achievement, generated X-ray energies will cover overall the 'water window' region. We are planning a multi-pulse inverse Compton scattering X-ray generation system in order to enhance a luminous intensity of the X-rays. For this purpose, we are considering a multi-pulse UV laser system for generating a multi-bunch electron beam, the method for beam loading compensation, and the multi-pulse IR laser system for the Compton collisions. Experimental results of X-ray generation and multi-pulse X-ray plans will be presented at the conference.

MOPC045	First Measurement Results of the PSI 500kV Low Emittance Electron Source	emittance, cathode, electron, optics	169
	M. Pedrozzi, Å. Andersson, R. J. Bakker, R. Ganter, C. Gough, C. P. Hauri, R. Ischebeck, S. Ivkovic, Y. Kim, F. Le Pimpec, K. B. Li, P. Ming, A. Oppelt, M. Paraliev, T. Schietinger, V. Schlott, B. Steffen, A. F. Wrulich PSI, Villigen S. C. Leemann MAX-lab, Lund
	The Paul Scherrer Insitute (PSI) is presently developing a low emittance electron source for the PSI-XFEL project. The target beam parameters at the source are I=5.5 A, Q=0.2 nC and a slice emittance below 0.2 mm.mrad. The gun concept consists of a high gradient "diode“ stage followed by a two-frequency two-cell cavity to allow fine tuning of the longitudinal phase space. This paper reports on the first experimental results obtained with the PSI 500 kV test stand. The facility consists of a 500 kV diode stage followed by a diagnostic beam line including an emittance monitor. An air-core transformer based high voltage pulser is capable of delivering a pulse of 250 ns FWHM with amplitude up to 500 kV. The diode gap between two mirror polished electrodes is adjustable to allow systematic gradient studies. The electrons are produced by a 266nm UV laser delivering 4μJoules on the Cu-cathode.

MOPC046	Femtoslicing at BESSY - Detecting More Photons	photon, background, single-bunch, electron	172
	T. Quast, K. Holldack BESSY GmbH, Berlin S. Khan Uni HH, Hamburg R. Mitzner Universität Muenster, Physikalisches Institut, Muenster
	The BESSY femtoslicing facility is now well established* and has proven its succesful operation for femtosecond laser-pump and x-ray-probe experiments*. However, many interesting physical phenomena cannot be addressed with the presently available comparably low number of photons detected at the sample. The most direct way to increase the photon flux is to increase the laser repetition rate. In order to preserve the excellent fs-signal to ps-background ratio special storage ring fill patterns and corresponding laser synchronisation schemes have been studied. We present calculations showing the influence of a dedicated new radiator promising better flux and polarisation properties. Recent results from a new beamline based on high transmission reflection zone plates will be presented. A new avalanche photo diode-array-based detection system has been successfully tested. This allows a parallel detection in the dispersion plane behind the monochomator. The status of these improvements will be presented. S. Khan et al. Phys. Rev. Lett, (97), 074801 (2006). **C. Stamm et al. Nature Mater. 6, 740 (2007).

MOPC047	Status of Kharkov X-ray Generator NESTOR Based on Compton Back Scattering	injection, electron, storage-ring, scattering	175
	I. M. Karnaukhov, V. P. Androsov, E. V. Bulyak, A. N. Dovbnya, I. V. Drebot, P. Gladkikh, V. A. Grevtsev, Yu. N. Grigor'ev, A. Gvozd, V. E. Ivashchenko, I. I. Karnaukhov, N. Kovalyova, V. P. Kozin, V. P. Lyashchenko, V. S. Margin, N. I. Mocheshnikov, A. Mytsykov, I. M. Neklyudov, F. A. Peev, A. Reuzaev, A. A. Shcherbakov, S. Sheyko, V. L. Skirda, Y. N. Telegin, V. I. Trotsenko, A. Y. Zelinsky, O. D. Zvonarjova NSC/KIPT, Kharkov J. I.M. Botman TUE, Eindhoven
	The purpose of the NESTOR (New Electron STOrage Ring) project is to create intense X-ray generator based on compact storage ring and Compton back scattering in the National Science Centre “Kharkov Institute of Physics and Technology”. It allows to carry out investigations in the wide range of fundamental and applied sciences such as physics, biology, medicine and so on. The facility consists of the compact 40-225 MeV storage ring, linear 35-90 MeV electron accelerator as an injector, transportation system and Nd:Yag laser and optical cavity. In addition to hard Compton radiation it is supposed to use 4 soft vacuum ultraviolet radiation channels of natural synchrotron radiation of dipole. The facility is going to be in operation in the middle of 2009 and the expected X-rays flux will be of about 10¹³ phot/s. In the paper the main facility parameters are presented.

MOPC053	BEAM DYNAMICS IN THE LASER-ELECTRON STORAGE RING FOR A COMPTON X-RAY SOURCE	electron, photon, scattering, lattice	187
	P.-CH. Yu, W.-H. Huang, C.-X. Tang, Y. Wang TUB, Beijing
	We present the lattice analysis and simulation study of the beam dynamics in the pulse mode of the laser-electron storage ring. Compton Scattering (CS), Intra-beam Scattering (IBS) with non-Gaussian beam and Synchro-tron Radiation (SR) are taken into consideration. Emittance growth, energy spread and phase space of the electron beam, as well as spatial and temporal distribution of the scattered photon are studied in this paper.

MOPC058	ALICE (ERLP) Injector Design	booster, emittance, gun, cathode	196
	B. D. Muratori, Y. M. Saveliev STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
	In this paper we look at how the ALICE (formerly ERLP) injector has been re-designed to meet more realistic criteria from the previous design. A key component of ALICE is the high brightness injector. The ALICE injector consists of a DC photocathode gun generating 80 pC electron bunches at 350 keV. These bunches are then matched into a booster cavity which accelerates them to an energy of 8.35 MeV. In order to do this, two solenoids and a single-cell buncher cavity are used, together with off-crest injection into the first booster cavity, where the beam is still far from being relativistic. The performance of the injector has been studied using the particle tracking code ASTRA.

MOPC061	Progress in R&D Efforts on the Energy Recovery Linac in Japan	linac, gun, electron, synchrotron	205
	S. Sakanaka, T. A. Agoh, A. Enomoto, S. Fukuda, K. Furukawa, T. Furuya, K. Haga, K. Harada, S. Hiramatsu, T. Honda, Y. Honda, K. Hosoyama, M. Izawa, E. Kako, T. Kasuga, H. Kawata, M. Kikuchi, H. Kobayakawa, Y. Kobayashi, T. Matsumoto, S. Michizono, T. Mitsuhashi, T. Miura, T. Miyajima, T. Muto, S. Nagahashi, T. Naito, T. Nogami, S. Noguchi, T. Obina, S. Ohsawa, T. Ozaki, H. Sasaki, S. Sasaki, K. Satoh, M. Satoh, M. Shimada, T. Shioya, T. Shishido, T. Suwada, T. Takahashi, Y. Tanimoto, M. Tawada, M. Tobiyama, K. Tsuchiya, T. Uchiyama, K. Umemori, S. Yamamoto KEK, Ibaraki R. Hajima, H. Iijima, N. Kikuzawa, E. J. Minehara, R. Nagai, N. Nishimori, M. Sawamura JAEA/ERL, Ibaraki H. Hanaki JASRI/SPring-8, Hyogo-ken A. Ishii, I. Ito, T. Kawasaki, H. Kudo, N. Nakamura, H. Sakai, S. Shibuya, K. Shinoe, T. Shiraga, H. Takaki ISSP/SRL, Chiba M. Katoh UVSOR, Okazaki Y. Kobayashi, K. Torizuka, D. Yoshitomi AIST, Tsukuba M. Kuriki HU/AdSM, Higashi-Hiroshima
	The future synchrotron light sources, based on the energy recovery linacs (ERL), are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. The ERL-based light sources are under development at such institutes as the Cornell University, the Daresbury Laboratory, the Advanced Photon Source, and KEK/JAEA. The Japanese collaboration team, including KEK, JAEA, ISSP, and UVSOR, is working to realize the key technologies for the ERLs. Our R&D program includes the developments of ultra-low-emittance photocathode DC guns and of superconducting cavities, as well as proofs of accelerator-physics issues at a small test ERL (the Compact ERL). A 250-kV, 50-mA photo-cathode DC gun is under construction at JAEA. Two single-cell niobium cavities have been tested under high electric fields at KEK. The conceptual design of the Compact ERL has been carried out. We report recent progress in our R&D efforts.

MOPC062	Results from ALICE (ERLP) DC Photoinjector Gun Commissioning	emittance, kicker, gun, electron	208
	Y. M. Saveliev, D. J. Holder, B. D. Muratori, S. L. Smith STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
	The Energy Recovery Linac Prototype (ERLP) DC photoinjector gun has been commissioned and the beam characteristics measured. The gun has demonstrated the nominal ERLP parameters of 350 keV electron energy, 80pC bunch charge and ~140 ps bunch length (at 10% level). The bunch parameters were measured at different bunch charges from 1 pC up to 80 pC. Special attention was given to measurements of the beam transverse emittance (using a movable slit), correlated and uncorrelated energy spread (using an energy spectrometer) and bunch length (using a transverse RF kicker) at each bunch charge. The effect of the 1.3 GHz RF buncher on the bunch length was also investigated. The experimental results are then compared with ASTRA simulations. Experimental results obtained from the investigation of several other issues including the beam characteristics in the presence of field emission from the cathode and in the presence of strong beam halo are also presented and discussed.

MOPC063	Characterisation of Electron Bunches from ALICE (ERLP) DC Photoinjector Gun at Two Different Laser Pulse Lengths	emittance, electron, gun, simulation	211
	Y. M. Saveliev, S. P. Jamison, L. B. Jones, B. D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
	In high-voltage DC photoinjector guns, the laser pulse duration affects the electron bunch characteristics and therefore is an important subject for experimental investigation and in the optimisation of the operation of the gun. Initial experimental study of this effect has been conducted using the Energy Recovery Linac Prototype (ERLP) photoinjector. During the commissioning of its DC photoinjector gun, the electron bunch parameters were measured at two laser pulse durations, ~7ps and ~28ps FWHM. The shorter laser pulse is the intrinsic output of the laser, while the longer pulse was produced with the use of a pulse stacker. The electron bunch parameters that were measured included transverse emittance, correlated and uncorrelated energy spread and bunch length. The experimental results and their comparison with computer simulations are presented and discussed.

MOPC066	Optimisation of a SRF High Average Current SRF Gun	cathode, gun, emittance, acceleration	220
	C. D. Beard, J. W. McKenzie, B. L. Militsyn, B. D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
	An approximately 100 mA and 10 MeV continuous wave electron injector is required to deliver high brightness electron bunches for the spontaneous and VUV radiation sources. One of possible solutions might be a Superconductive RF (SRF) gun. Optimisation of the first half cell of the gun has been carried out to maximise the acceleration whilst providing additional focussing through shaping of the cathode region to meet the design specification. In this paper, the cavity design and specification are presented together with some initial optimisations.

MOPC071	Development of a High Brightness Photo-Injector for Light Source Research at NSRRC	gun, electron, emittance, brightness	229
	W. K. Lau, J. H. Chen, C. S. Chou, G.-Y. Hsiung, K. T. Hsu, J.-Y. Hwang, A. P. Lee, C. C. Liang, G.-H. Luo, D.-J. Wang NSRRC, Hsinchu C. H. Chen, N. Y. Huang, Y.-C. Huang, W. K. Luo NTHU, Hsinchu
	A laser driven photo-cathode rf gun system is being installed at NSRRC gun testsite for high brightness electron beam and light source research. The photo-cathode rf gun cavity geometry has been modified from the BNL 1.6-cell structure for 2998 MHz operation. A 798 nm Ti:Saphire laser seeded 3 mJ regenerative amplifier is employed to produce 300 microjoules UV pulses at 266 nm wavelength from a third harmonic generator crystal for emission of photo-electrons from the Cu-cathode in the rf gun. First operation of this system with gaussian laser pulses is scheduled in summer 2008. Future plan for flattop laser pulse operation will be discussed.

MOPC072	Photocathode Studies at FLASH	cathode, vacuum, photon, electron	232
	S. Lederer, S. Schreiber DESY, Hamburg J. H. Han Diamond, Oxfordshire P. M. Michelato, L. Monaco, C. Pagani, D. Sertore INFN/LASA, Segrate (MI)
	Since several years, the DESY photoinjectors at FLASH and PITZ use cesium telluride photocathodes. One concern of operating an electron source with these cathodes is the degradation of the quantum efficiency (QE), starting from about 10 % to below 0.5 % during operation. To further understand this behavior the QE is monitored routinely. In this paper recent results from photocathode studies at FLASH are presented.

MOPC073	Design of an Upgrade to the ALICE Photocathode Electron Gun	electron, gun, vacuum, cathode	235
	B. L. Militsyn, B. D. Fell, L. B. Jones, J. W. McKenzie, K. J. Middleman STFC/DL/ASTeC, Daresbury, Warrington, Cheshire I. Burrows, R. J. Cash STFC/DL, Daresbury, Warrington, Cheshire S. N. Kosolobov, H. E. Scheibler, A. S. Terekhov ISP, Novosibirsk
	The design of an upgrade to the GaAs photocathode electron gun of the Energy Recovery Linac Prototype (ERLP) at Daresbury Laboratory is presented. This proposed upgrade includes a reduction of the photocathode diameter from 32 to 10 mm and the installation of a dedicated photocathode preparation system with side loading of the photocathodes. The preparation system forms a united vacuum system with the gun but is separated by a gate valve. This allows for significant improvements to the vacuum conditions in the gun and a reduction of pollution from caesium vapour which improves gun stability under high voltage. This preparation facility will reduce the time taken for photocathode changeover from weeks to hours. The facility should provide photocathodes with higher quantum efficiency due to a more controllable preparation procedure and allows experiments to be performed with photocathodes activated to different levels of electron affinity.

MOPC080	Status of the FERMI@Elettra Photoinjector	gun, electron, diagnostics, controls	247
	M. Trovo, L. Badano, S. Biedron, D. Castronovo, F. Cianciosi, P. Craievich, G. D'Auria, M. B. Danailov, M. Ferianis, S. V. Milton, G. Penco, L. Pivetta, L. Rumiz, D. Wang ELETTRA, Basovizza, Trieste H. Badakov, A. Fukasawa, B. D. O'Shea, J. B. Rosenzweig UCLA, Los Angeles, California M. Eriksson, D. Kumbaro, F. Lindau MAX-lab, Lund
	The new FERMI@Elettra photoinjector is presently undergoing high-power testing and characterization at MAX-Lab in Lund Sweden. This effort is a collaboration between Sincrotrone Trieste, MAX-Lab and UCLA. The 1.6-cell RF gun cavity and the focusing solenoid were successfully designed and built by the Particle Beam Physics Laboratory at UCLA, delivered to Sincrotrone Trieste at the beginning of 2008, and installed in the linac tunnel at MAX-Lab. Use of the MAX-Lab facility will allow the FERMI project to progress significantly with the photoinjector while waiting for the completion of the new linac building extension at Sincrotrone Trieste. We report here on the high-power conditioning of the RF cavity and the first beam tests. Furthermore, a preliminary characterization of the 5 MeV beam will also be presented.

MOPC083	Flat Long Pulse Train Formation Using Multi-pass Structure	insertion, alignment, polarization, gun	250
	J. Ruan, H. T. Edwards, R. P. Fliller Fermilab, Batavia, Illinois
	Flat long pulse train is part of the requirements for International Linear collider. Here in Fermilab the construction of ILCTA at New Meon Lab will present the similar requirements (3MHz, 2810 Pulses, 5Hz) for the laser systems. In this paper we will report the effort to develop a new multi pass (MP) cavity based on Nd:YLF crystal end-pumped by diode laser. It takes a seed (1054 nm, 4-5ps) from a commercial laser and has a gain of 1000 or more. So far we already tested up to 1000 pulses with 1μs spacing and the pulse train amplitude fluctuation is less than 5% throughout the whole duration. We attribute this to the high optical to optical conversion efficiency achieved using Nd:YLF crystal inside the multi-pass structure. Test with 3MHz spacing train is also discussed and the integration of the new MP cavity into the current laser system is planned.

MOPC084	A Laser-driven Acceleration Method	ion, plasma, target, acceleration	253
	L. Torrisi, S. Gammino, D. Margarone INFN/LNS, Catania A. Borrielli, F. Caridi INFN & Messina University, S. Agata, Messina
	A laser ion source (LIS) has been obtained with a repetitive pulsed laser at power density of the order of 10¹⁰ W/cm² or higher, with pulse duration of the order of ns and repetition rate of the order of tens Hz. Any solid target can be ablated producing plasma with equivalent temperatures higher than 100 eV, densities higher than 10¹⁷/cm³ and charge states higher than 10⁺. Extracted current densities can be higher than 10 mA/cm². The study of the electric fields generated inside the non equilibrium plasmas is a by-product of the research in ion generation. Ions are emitted from the plasma in the direction of the electric field with energies of the order of 50 eV/nucleon or higher, depending on the laser intensity. Emitted ions have a Boltzmann ion energy distribution depending on the ion charge state. Previous papers show that the electric field is as high as 10 MV/cm in our case. Magnetic trapping of electrons has been used to increase the ion acceleration, focusing and current. This new ion acceleration method based on LIS seems to be very interesting because it may permit to build accelerators with small dimensions and relatively low cost.

MOPC122	Experiments with Fe-ion Beam Generation Acceleration and Accumulation in ITEP-TWAC Facility	ion, target, vacuum, injection	352
	B. Y. Sharkov, P. N. Alekseev, N. N. Alexeev, A. Balabaev, V. I. Nikolaev, V. A. Schegolev, A. Shumshurov, V. P. Zavodov ITEP, Moscow Y. Satov SRC RF TRINITI, Moscow region
	The laser ion source (LIS) developed in collaboration ITEP-TRINITI-CERN with an upgraded version of powerful 100J CO2-laser has been used for Fe-ion beam generation at the input of the pre-injector U-3 delivering separated species of Fe¹⁶⁺ ions with energy of 1.1 MeV/u to booster synchrotron UK for acceleration up to the energy of 160 MeV/u and accumulation in the storage ring U-10 using multiple charge exchange injection technique. First results of Fe-ion beam treating from laser ion source to accumulator ring are presented.

MOPC147	Measurement of Ion Beam from Laser Ion Source for RHIC EBIS	ion, plasma, target, ion-source	421
	T. Kanesue Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka M. Okamura BNL, Upton, Long Island, New York J. Tamura Department of Energy Sciences, Tokyo Institute of Technology, Yokohama
	Laser ion source (LIS) is a candidate of the primary ion source for the RHIC EBIS. LIS will provide intense charge state 1⁺ ions to EBIS for further ionization. We measured plasma properties of a variety of atomic species such as Si, Fe and Au using the second harmonics of Nd:YAG laser (532 nm wave length, up to 0.82 J / 6 ns). Since a suitable laser power density for production of charge state 1+ ions is different from different species, laser power density was optimized to obtain a maximum beam intensity in each species. Also the results of emittance measurement using pepper pot after ion extraction with about 20 kV extraction voltage will be shown. Based on the obtained results, performance of the LIS as the primary ion source for EBIS will be discussed in this paper.

MOPC148	Target Life Time of Laser Ion Source for Low Charge State Ion Production	target, ion, vacuum, ion-source	424
	T. Kanesue Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka M. Okamura BNL, Upton, Long Island, New York J. Tamura Department of Energy Sciences, Tokyo Institute of Technology, Yokohama
	Laser ion source produces ions by irradiating pulsed laser shots onto the solid state target. For the low charge state ion production, laser spot diameter on the target can be over several millimeters using the high power laser such as Nd:YAG laser (532 nm wave length, 0.82 J / 6 ns). In this case, damages to the target surface is small while there is a visible crater in case of the best focused laser shot (laser spot diameter can be several tens of micrometers) for high charge state ion production. Because damage to the target surface is small, target is not required to be moved to use fresh surface after each laser shot to stabilize plasma. In this paper, the results of target life time measurements will be shown.

MOPP013	Coupler Kick for Very Short Bunches and its Compensation	emittance, focusing, betatron, radio-frequency	580
	M. Dohlus, I. Zagorodnov DESY, Hamburg E. Gjonaj, T. Weiland TEMF, Darmstadt
	In this contribution we estimate two different effects: the kick due to asymmetry of the external accelerating field (coupler RF kick) and the kick due to electromagnetic field of the bunch scattered by the couplers (coupler wake kick). We take into acoount the cavities and calculate the periodic solution for bunch with an rms width of 300 mkm. The different possibilities for compensation of the kick are considered.

MOPP022	Transatlantic Transport of Fermilab 3.9 GHZ Cryomodule for TTF/FLASH to DESY	alignment, acceleration, survey, vacuum	592
	M. McGee, V. T. Bocean, J. Grimm, W. Schappert Fermilab, Batavia, Illinois
	In an exchange of technology agreement, Fermilab built and will deliver a 3.9 GHz (3rd harmonic) cryomodule to DESY to be installed in the TTF/FLASH beamline. This cryomodule delivery will involve a combination of flatbed air ride truck and commercial aircraft transport to Hamburg Germany. A description of the isolation and damping systems that maintain alignment during transport and protect fragile components is provided. Initially, transport and corresponding alignment stability studies were performed in order to assess the risk associated with transatlantic travel of a fully assembled cryomodule. Shock loads were applied to the cryomodule by using a coldmass mockup to prevent subjecting actual critical components (such as the cavities and input couplers) to excessive forces. Accumulative and peak shock loads were applied through over-the-road testing and using a pendulum hammer apparatus, respectively. Finite Element Analysis (FEA) studies were implemented to define location of instrumentation for transport studies and provide modal frequencies and shapes. Shock and vibration measurement results of transport studies and stabilization techniques are discussed.

MOPP035	ILC Siting in Dubna Region (Russia) and ILC activity in JINR	site, collider, diagnostics, linear-collider	622
	G. Shirkov, Ju. Boudagov, Yu. N. Denisov, I. N. Meshkov, A. N. Sissakian, G. V. Trubnikov JINR, Dubna, Moscow Region
	The report presents the development of investigations on ILC siting in the Dubna region and ILC technical activity at JINR. Russia is one of candidates now for ILC hosting in the Dubna region. International intergovernmental status of JINR, stable geological and plain relief conditions comfortable location, well developed infrastructure create powerful advantages of JINR among other possible sites. Shallow layout of tunnels and experimental halls could significantly reduce the cost of conventional facilities and siting. Besides JINR physicists take part in several fields of activity in ILC: works on photo injector prototype, participation in design and construction of cryomodules, laser metrology, etc.

MOPP075	Experimental Generation and Characterization of Uniformly Filled Ellipsoidal Electron Beam Distributions	electron, cathode, space-charge, emittance	724
	P. Musumeci, J. Moody, J. B. Rosenzweig, C. M. Scoby UCLA, Los Angeles, California
	For forty years, uniformly filled ellipsoidal beam distributions have been studied theoretically, as they have had the promise of generating self-fields that produce forces linear in the coordinate offset in all three directions. More recently, a scheme for producing such distributions, which depends on the strong longitudinal expansion of an initially very short beam under its own space charge forces, has been proposed. Here we present the experimental demonstration of this scheme, obtained by illuminating the cathode in an rf photogun with an ultra-short laser pulse (~35 fs rms) with an appropriate transverse profile. The resulting 4 MeV beam spatiotemporal (x,t) distribution is imaged using an rf deflecting cavity with 50 fsec resolution. A temporal asymmetry in the ellipsoidal profile, due to image charge effects at the photocathode, is observed at higher charge operation. This distortion is also found to degrade the transverse beam quality.

MOPP078	Femtosecond Photocathode Electron Source	electron, emittance, gun, injection	730
	J. Yang, K. Kan, T. Kondoh, K. Tanimura, Y. Yoshida ISIR, Osaka J. Urakawa KEK, Ibaraki
	A photocathode-based low-emittance femtosecond-bunch electron source is developed to reveal the hidden dynamics of intricate molecular and atomic processes in materials through experimentation such as time-resolved pulse radiolysis or time-resolved electron diffraction. The transverse and longitudinal dynamics of femtosecond electron beam in a photocathode rf gun were studied. The growths of the emittance, bunch length and energy spread due to the rf and the space charge effects in the rf gun were investigated by changing the laser injection phase, the laser pulse width and the bunch charge. The beam simulation indicates that a sub-100-fs MeV electron source with the normalized transverse emittance of 0.1 mm-mrad and the relative energy spread of 10^-4 at bunch charge of 0.1-1pC is achievable in the photocathode rf gun driven by a femtosecond laser light.

TUOAM02	The Status of the Daresbury Energy Recovery Linac Prototype	gun, linac, diagnostics, radiation	1001
	D. J. Holder, P. A. McIntosh, S. L. Smith STFC/DL/ASTeC, Daresbury, Warrington, Cheshire N. Bliss STFC/DL, Daresbury, Warrington, Cheshire A. R. Goulden STFC/DL/SRD, Daresbury, Warrington, Cheshire
	This paper provides an update on the progress with the building and commissioning of the Energy Recovery Linac Prototype (ERLP). The past year has seen a number of notable achievements as well as a number of obstacles to overcome. The detailed results from the gun commissioning work are described elsewhere at this conference. ERLP is a 35 MeV technology demonstrator being built as part of the UK's R&D programme to develop its next-generation light source (NLS). It is based on a combination of a DC photocathode electron gun, a superconducting injector linac and a main linac operating in energy recovery mode. These drive an IR-FEL, an inverse Compton Back-Scattering (CBS) x-ray source and a terahertz beamline. The priorities for ERLP are to gain experience of operating a photoinjector gun and superconducting linacs; to produce and maintain high-brightness electron beams; to achieve energy recovery from an FEL-disrupted beam; the development of an electro-optic longitudinal profile monitor and to study challenging synchronisation issues. ERLP will also act as an injector for what will be the world's first non-scaling, Fixed-Field Alternating Gradient (FFAG) accelerator called EMMA.
	Slides

TUPC011	Micron Size Laser-wire System at the ATF Extraction Line	electron, diagnostics, simulation, optics	1065
	A. Aryshev, G. A. Blair, S. T. Boogert, G. E. Boorman, A. Bosco, L. Corner, L. Deacon, N. Delerue, B. Foster, F. Gannaway, D. F. Howell, V. Karataev, L. J. Nevay, M. Newman, R. Senanayake, R. Walczak JAI, Egham, Surrey H. Hayano, N. Terunuma, J. Urakawa KEK, Ibaraki
	The ATF extraction line laser-wire system has recently been upgraded allowing the measurement of micron scale transverse size electron beams. We report on the hardware upgrades, including focusing lens, laser and mechanical systems. First measurements using the new system from recent operation at the ATF in KEK are presented.

TUPC024	Video Profile Monitors Development for the CTF3 Probe Beam Linac	linac, diagnostics, emittance, collider	1101
	W. Farabolini, G. Adroit, P. Girardot, R. Granelli, F. Harrault, C. L.H. Lahonde-Hamdoun, T. Lerch, F. Orsini CEA, Gif-sur-Yvette
	The innovative CLIC concept is currently under study in the CLIC Test Facility (CTF3) at CERN where the acceleration of a probe beam will be demonstrated. This probe beam, delivered by a linac called CALIFES, is composed of short bunches (0.75 ps, 0.6 nC) at 170 MeV with normalized emittance lower than 20 mm.mrad. Measurements of longitudinal charges distribution, transverse emittance and energy spectrum rely on Video Profile Monitors (VPM) after appropriate manipulations of the beam (deflecting cavity, quad scan and analysis dipole). We report the design, development and tests of these new VPMs based on selectable YAG/OTR screens, optical line and CCD camera. Two selectable magnifications (1.75 and 0.33) are available via motorized lens mounts to comply both with resolution (20 μm) and field of view (10x10mm²). Study of optical line characteristics have been realised with Apilux software and Modulation Transfer Function (MTF) were measured. A grid pattern can be inserted at the screens position to check optical characteristics during operations. Tilt of the CCD plan in order to compensate the screen tilt of 15° has not proven to improve the depth of field and was not implemented.

TUPC027	Spatial Autocorrelation for Transverse Beam Quality Characterization	emittance, focusing, space-charge, brightness	1107
	V. Fusco, M. Ferrario INFN/LNF, Frascati (Roma) C. Ronsivalle ENEA C. R. Frascati, Frascati (Roma)
	Low emittance beams are required for high brightness beams applications. Contributions to emittance degradations come from electromagnetic fields’ non-linearities which can be reduced using a transversally and longitudinally uniform beam. For these reasons the evaluation of the beam quality is a very important task. Concerning the transverse analysis the spatial correlation parameter has been introduced: it gives an evaluation of how beam non-uniformity is distributed. The paper describes the spatial autocorrelation concept and applies it to the evaluation of a laser beam for high brightness beam applications. Moreover the paper shows the spatial autocorrelation evolution along a photo-injector as an additional tool for beam dynamics studies.

TUPC042	Limitations of Electro-optic Longitudinal Electron Bunch Length Measurements	simulation, resonance, diagnostics, coupling	1149
	S. P. Jamison STFC/DL/ASTeC, Daresbury, Warrington, Cheshire G. Berden FOM Rijnhuizen, Nieuwegein W. A. Gillespie, P. J. Phillips University of Dundee, Nethergate, Dundee, Scotland A. MacLeod UAD, Dundee
	Electro-optic (EO) techniques are becoming increasingly important in ultrafast electron bunch longitudinal diagnostics and have been implemented at various accelerator labs. A crucial aspect of any implementation is a robust assessment of its resolution capabilities. However the assessments of the temporal limitations often differ between groups and the assumptions employed in deriving these limitations are frequently not addressed. With EO measurements of intense CTR pulses and ultrafast Coulomb fields, it may also be necessary to reconsider the validity of the usual interpretation of the EO effect as a phase retardation proportional to the Coulomb field. From a generic analysis of various sources of the temporal limitations we present a summary of the capability of various EO techniques which can be applied to specific implementations with differing laser and bunch parameters. As well as specifying the quantitative limitations and their scaling with experimental parameters, the qualitative effects of distortion in the measured profile are also summarised. Additional limitations, which arise from a breakdown of the phase-retardation interpretation of the EO effect, are discussed.

TUPC045	Setup and Commissioning of the Diagnostics Beamline for the SRF Photoinjector Project at Rossendorf	electron, diagnostics, gun, cathode	1158
	T. Kamps, D. Böhlick, M. Dirsat, T. Quast, J. Rudolph, M. Schenk BESSY GmbH, Berlin A. Arnold, F. Staufenbiel, J. Teichert FZD, Dresden G. Klemz, I. Will MBI, Berlin D. Lipka DESY, Hamburg
	A superconducting radio frequency photo electron injector (SRF injector) has been developed by a collaboration of BESSY, DESY, FZD and MBI and is in operation since late 2007. After the initial commissioning in late 2007 with a Copper photocathode a Caesium-Telluride cathode was installed early 2008 to allow for high charge production. The longitudinal and transverse electron beam parameters are measured in a compact diagnostics beamline. This paper describes results from beam commissioning of the main diagnostic tools. Special emphasis is given on the bunch length measurement system for the 15 ps FWHM electron bunches. The system is based on the conversion of the electron pulses into radiation pulses by Cherenkov radiation. These radiation pulses are transported in a novel fully-reflective, relay imaging optical beamline to a streak camera, where the temporal properties of the pulses are measured. Results from beam measurements at 2pC (Copper cathode) and 1nC (Cesium-Telluride cathode) bunch charge are presented and discussed.

TUPC058	Laser-based Ion Beam Diagnostics for the Front End Test Stand at RAL	electron, ion, background, vacuum	1188
	D. A. Lee, J. K. Pozimski Imperial College of Science and Technology, Department of Physics, London C. Gabor STFC/RAL/ASTeC, Chilton, Didcot, Oxon
	The RAL Front End Test Stand is being constructed to demonstrate that a chopped H^- beam of 60 mA at 3 MeV with 50 pps and sufficiently high beam quality as required for future high-power proton accelerators can be produced. Because of the high beam power and a preference for online beam monitoring non-intrusive, non-destructive beam diagnostics are desirable. Two novel instruments, based on the photo-detachment of the outer electron of the H^- ions with a laser, are being developed to precisely determine the transverse beam density distribution and the beam emittance at full beam power. This paper discusses the proposed experimental layout of the devices and the progress that has been made towards realizing them. The design of the optical system is presented along with measurements of the laser beam propagation for the beam density distribution experiment. Investigations of the influence of laser beam misalignment along with measurements of the positioning accuracy of movable stages that will be used are given in light of the total expected errors.

TUPC061	Laser Wire Beam Profile Monitor at Spallation Neutron Source (SNS)	ion, electron, controls, linac	1197
	Y. Liu, S. Assadi, W. P. Grice, C. D. Long ORNL, Oak Ridge, Tennessee
	We report the first measurement of a hydrogen ion beam profile in the superconducting linear accelerator (SCL) at the Spallation Neutron Source (SNS) with a laser wire beam profile monitor. The advantage of the laser beam profile monitor includes non-invasive measurement, longitudinal beam scan and multiple station measurement capabilities. A Q-switched Nd:YAG laser at 1.06 μm is used to detach electrons from hydrogen ions. The laser has a repetition rate of 30 Hz and a pulse width of 7 ns. Typical pulse energies are 50 - 200 mJ. The laser is physically located outside the SCL tunnel and the ion beam profiles are measured at 9 different locations covering the entire SCL region (~ 200 m). At SNS the beam structure consists of 50 ps long micropulses separation by ~ 2.5 ns and gated into macropulses of up to 1 ms long. The firing of the laser flashlamps is synchronized to the macropulse timing. The collection magnet bends the photodetached electrons out of the beam and into a Faraday cup. Both horizontal and vertical beam profiles (typical width: 2 - 4 mm) can be measured with a resolution of 4 um. Transverse beam scans can be performed throughout the macropulse.

TUPC075	Development Status of a Beam Diagnostic System with a Spatial Resolution of Ten Micron-meters for XFEL	electron, radiation, undulator, 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	diagnostics, electron, emittance, undulator	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.

TUPC081	Single-shot Longitudinal Bunch Profile Measurements at FLASH Using Electro-optic Detection Techniques	electron, resonance, linac, simulation	1242
	P. J. Phillips, W. A. Gillespie University of Dundee, Nethergate, Dundee, Scotland V. R. Arsov, H. Schlarb, B. Schmidt, P. Schmüser DESY, Hamburg G. Berden, A. F.G. van der Meer FOM Rijnhuizen, Nieuwegein S. P. Jamison STFC/DL/ASTeC, Daresbury, Warrington, Cheshire A. MacLeod UAD, Dundee B. Steffen PSI, Villigen
	At the superconducting linac of FLASH at DESY, we have installed an electro-optic experiment for single-shot, non destructive measurements of the longitudinal electric charge distribution of individual electron bunches. The profile of the electron bunch field is electro-optically encoded onto a streched Ti:Sa laser pulse. In the decoding step, the profile is retrieved from a spectral measurement of the encoded pulse or from a cross-correlation of the encoded pulse with a 35 fs laser pulse , obtained from the same laser. At FLASH, sub-100 fs electron bunches have been measured during FEL operation with a resolution of better than 50 fs. The electro-optic measurements have been validated with a tranverse deflecting cavity measurements.

TUPC090	Ionisation Profile Monitor to Determine Spatial and Angular Stability of FEL Radiation of FLASH	ion, simulation, electron, photon	1266
	M. Sachwitz, A. Hofmann, S. Pauliuk DESY Zeuthen, Zeuthen K. I. Tiedtke, H. Wabnitz DESY, Hamburg
	An Ionization Profile Monitor (IPM) is used to detect lateral position changes of an FEL beam. By its help, beam position stability can be measured via the parasitic ionization of the residual gas in the beamline. We give an outline on operation, calibration and maintenance of the two IPM that have been developed at DESY Zeuthen and that have recently been built into FLASH at DESY Hamburg.

TUPC094	Longitudinal Bunch Profile Monitoring via Single Shot Diagnostic with Linear Response	electron, diagnostics, monitoring, polarization	1278
	U. Schmidhammer, V. De Waele, J.-P. Larbre, J.-L. Marignier, H. Monard, M. Mostafavi CLIO/ELISE/LCP, Orsay N. Bourgeois, J.-R. Marquès LULI, Palaiseau
	A new approach of electro-optic (EO) spectral encoding allows for the non-invasive characterization of the longitudinal electron bunch distribution at the ELYSE laser triggered ps pulse radiolysis facility: the transverse electric field of the relativistic bunch is encoded to the temporally dispersed spectrum of a supercontinuum whose wavelength dependent polarisation state is then analyzed with balanced detection. This method combines the spectral bandwidth of the probe that corresponds to a Fourier transform limit < 5 fs with a direct signal response of the detection scheme. As a result, the field amplitude within the EO crystal can be determined in an absolute, undistorted manner with a time window several times longer than the electron pulse. For a time window easily tunable between 0.5 to 100 ps the possible time resolution is ~ 70 fs respectively 1 ps. The diagnostic allows bunch monitoring at the 100 pC level even for low beam energy and brightness. The influence of the accelerator conditions on the charge profile and its stability was able to be studied for the 8 MeV bunches at ELYSE with a 0.5 mm thick ZnTe crystal in a distance of 4 mm to the beam centre.

TUPC111	Overview of the Diagnostics Systems of PETRA III	feedback, diagnostics, pick-up, emittance	1323
	G. Kube, K. Balewski, A. Brenger, H. T. Duhme, V. Gharibyan, J. Klute, K. Knaack, I. Krouptchenkov, T. Lensch, J. Liebing, D. Lipka, R. Neumann, R. Neumann, G. Priebe, F. Schmidt-Foehre, H.-Ch. Schroeder, R. Susen, S. Vicins, M. Werner, Ch. Wiebers, K. Wittenburg DESY, Hamburg
	Since mid-2007, the existing storage ring PETRA at DESY is reconstructed towards a dedicated third generation hard x-ray light source operating at 6 GeV with 100 mA stored current. The reconstruction includes the total rebuilding of one-eights of the storage ring. In this part the FODO lattice of the arcs is replaced by double-bend achromat cells, resulting in straight sections for 14 insertion device beamlines. Damping wigglers with a total length of 80 m are installed to reduce the emittance down to the design value of 1 nm rad. In order to fully benefit from this low emittance, beam stability is a crucial issue. For the achievement of the required performance and to allow a safe machine operation a number of beam instrumentation is required. Here the diagnostics system for the electron beam is presented with special emphasis on the essential instruments, i.e. the high resolution BPM system, profile monitors, feedback systems, and the machine protection system.

TUPC114	Results from the Optical Replica Experiments in FLASH	electron, undulator, 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.

TUPC116	Field Characterization of XFEL Quadrupole Magnets	quadrupole, electron, alignment, controls	1338
	A. Hedqvist, H. Danared, F. Hellberg MSL, Stockholm J. Pflueger DESY, Hamburg
	The European X-ray free electron laser (XFEL) will be one of the most advanced light source facilities in Europe and produce high intensity laser light of wavelengths down to 0.1 nm. The laser light is produced and amplified by electrons moving through long undulator systems, each consisting of several 5 m long segments. After each undulator segment an adjustable quadrupole magnet is placed to focus the electron beam. For optimum control of the laser light the centre of the quadrupoles need to be positioned along a straight line with an accuracy of 0.001 mm which only can be reached by beam based alignment (BBA). Prior to the BBA procedure the magnets need to be aligned along the beam path, therefore the centre position of the magnet has to be determined relative to fiducials placed on the magnet body with an accuracy of approximately 0.01 mm. A rotating coil system has been set up at the Manne Siegbahn Laboratory to characterize the magnetic field between the four magnetic poles and to measure the stability of the magnetic centre. The accuracy of this instrument and procedures of how to fiducialize the magnetic centre are presented. European XFEL technical design report, edited by M. Altarelli et. al., DESY 2006.

TUPC118	First Data from the Linear Collider Alignment and Survey Project (LiCAS)	survey, alignment, linear-collider, collider	1344
	A. Reichold, T. Handford, L. A. Rainbow, M. Tacon, C. Uribe Estrada, D. Urner, S. Q. Yang OXFORDphysics, Oxford, Oxon P. J. Brockill, S. Cohen, J. Dale, M. Dawson, M. Jones, G. Moss, R. Wastie JAI, Oxford G. Grzelak Warsaw University, Warsaw J. Prenting, M. Schloesser DESY, Hamburg
	The LiCAS project has developed a prototype robotic survey system for rapid and highly accurate surveying of long linear accelerator tunnel networks. It is aimed at the survey of the reference network for the International Linear Collider (ILC). This Rapid Tunnel Reference Surveyor (RTRS) is designed to be an R\&D instrument for evaluating the potential performance of the RTRS concept and its survey technology. The prototype has been commissioned in a test tunnel at DESY with initial calibrations and measurements ongoing. We will report on the results obtained so far and present conclusions for the design of an RTRS suitable for the ILC.

TUPC121	Nanometre Precision Interferometric Stability Monitoring Systems for Key Accelerator Components	quadrupole, monitoring, alignment, linear-collider	1350
	P. A. Coe, A. Reichold, D. Urner OXFORDphysics, Oxford, Oxon M. S. Warden JAI, Oxford
	The MONALISA group develops novel, accurate, nanometre resolution, interferometric systems to monitor relative motions between key accelerator components. We use cost-effective technology developed for the telecommunications market, providing readily scalable, adaptable solutions. Key magnets and diagnostics in the beam-delivery section of the International Linear Collider (ILC) will need to maintain stable relative positions. In particular, the final focus quadrupole magnets require nanometre level stability. Even greater stability requirements will be placed on components for the Compact Linear Accelerator (CLIC). Interferometers provide the only means of monitoring relative positions over long timescales, at the nanometre and sub-nanometre level. We are working to improve our measurement resolution using an optical frequency reference obtained by locking the second harmonic of an ultra-narrow linewidth 1560 nm fibre laser to a D2 transition in Rubidium-87. The latest results from this system tested on novel design, fibre-coupled, evacuated interferometers will be presented.

TUPC123	An Electro-Optic Deflector for a Fast Laser-Wire Scanner	controls, radiation	1356
	A. Bosco, G. A. Blair, S. T. Boogert, G. E. Boorman Royal Holloway, University of London, Surrey
	A large aperture electro-optic deflector has been designed, realized and tested for application on a laser-wire scanner for particle accelerators. Results on the important parameters such as deflection strenght, speed and mode quality preservation are shown and discussed.

TUPC124	Development of a High Power Fibre Laser for Laser Based Electron Beam Diagnostics	collider, linear-collider, electron, scattering	1359
	L. Corner, N. Delerue, M. Newman, R. Walczak OXFORDphysics, Oxford, Oxon G. A. Blair, S. T. Boogert Royal Holloway, University of London, Surrey L. Corner, D. F. Howell, L. J. Nevay JAI, Oxford
	We present the latest results on the development of a high power fibre laser system for the laserwire project on ILC-like laser based electron beam diagnostics. The laser consists of a solid state oscillator which can be synchronised to an external frequency reference, and two amplification stages in double clad doped fibre, giving 1uJ pulses in a burst mode suitable for the ATF2 laserwire project. This output is amplified in large mode area photonic crystal fibre to generate the high pulse energy necessary for Compton scattering without any deleterious nonlinear effects, whilst maintaining the high spatial mode quality and beam pointing stability of a fibre laser. These properties are essential for producing the sub-micron spot sizes required for the measurement of small particle beam sizes.

TUPC135	Experimental Determination of the Timing Stability of the Optical Synchronization System at FLASH	electron, controls, polarization, cathode	1386
	F. Loehl, V. R. Arsov, M. Felber, K. E. Hacker, B. Lorbeer, F. Ludwig, K.-H. Matthiesen, H. Schlarb, B. Schmidt DESY, Hamburg S. Schulz, A. Winter, J. Zemella Uni HH, Hamburg
	An optical, drift free synchronization system with a stability of better than 10 fs is presently being installed at the free electron laser FLASH. A periodic laser pulse train from a mode-locked, erbium doped fiber laser is distributed via length stabilized fiber links. In this paper, we present measurements of the timing stability of the optical distribution system. Two arrival time monitors (BAM) are used to measure the electron bunch arrival times at two positions in the linac separated by 60 m. Each BAM is supplied with fiber-laser pulses by its own fiber link. By correlating the measured arrival times of the same electron bunches, the overall performance of the optical distribution system and the BAMs can be evaluated. A resolution and timing stability of better than 30 fs has beed reached.

TUPC141	Concept and Implementation of the SC Cavity Resonance Frequency Monitor for the Digital RF Field Controller	controls, resonance, klystron, monitoring	1398
	W. Jalmuzna, A. Napieralski TUL-DMCS, Łódź S. Simrock DESY, Hamburg
	New generations of digital control systems offer large number of computation resources together with precise ADCs (analog to digital converters) and DACs (digital to analog converters) which can be used to generate almost any klystron driving signal. This gives the possibility to implement such features as digital SEL (self excited loop) and frequency sweep mode. They can be used to monitor resonance frequency of SC cavities. This information can be used by tuning system to adjust cavity tuner settings. Such functionality is valuable especially during the first RF station start up when the cavities may be detuned even by a large frequency. The paper presents the concept of such system and summarizes implementation and tests performed at FLASH facility (DESY, Hamburg).

TUPC142	Performance of 24 Cavity Vector Sum Controller with Distributed Architecture	controls, klystron, electron, electromagnetic-fields	1401
	W. Jalmuzna, A. Napieralski TUL-DMCS, Łódź
	The paper presents the test results of the digital vector sum control applied for 24 superconducting cavities driven by 1 klystron. The controller is based on FPGA chips and consists of multiple processing boards which communicate via optical fiber links. Flexible and scalable distributed architecture was designed and implemented to provide framework for the control algorithms. The tests were performed at FLASH (DESY, Hamburg) facility using ACC4, ACC5 and ACC6 modules. Results were compared to the existing DSP based system.

TUPD027	Commissioning of the Offline-teststand for the S-DALINAC Polarized Injector SPIN	electron, polarization, cathode, scattering	1482
	C. Heßler, R. Barday, U. Bonnes, M. Brunken, C. Eckardt, R. Eichhorn, J. Enders, M. Platz, Y. Poltoratska, M. Roth TU Darmstadt, Darmstadt W. Ackermann, W. F.O. Müller, B. Steiner, T. Weiland TEMF, Darmstadt K. Aulenbacher IKP, Mainz
	At the superconducting Darmstadt linear electron accelerator S-DALINAC a new injector for polarized electrons is under development. For this purpose an off-line test stand has been constructed. It consists of the source of polarized electrons and a test beamline including a Wien filter for spin manipulation, a Mott polarimeter for polarization measurement and various beam steering and diagnostic elements. The polarized electron beam is produced by photoemission from a strained GaAs cathode. We report on the status of this project and present first results of the measurements of the beam properties. We also give an outlook on the upcoming installation of SPIN at the S-DALINAC.

TUPP001	Alternating Gradient Operation of Accelerating Modules at FLASH	controls, feedback, electron, klystron	1523
	V. Ayvazyan, G. Petrosyan, K. Rehlich, S. Simrock, E. Vogel DESY, Hamburg H. T. Edwards Fermilab, Batavia, Illinois
	The free electron laser in Hamburg (FLASH) is a user facility providing high brilliant laser light for experiments. It is also an unique facility for testing the superconducting accelerator technology for the European XFEL and the international linear collider (ILC). The XFEL offers several beam lines to users. Within limits given by the beam delivery system the bunch pattern and beam energy should be adjustable independent for each beam line suggesting a time sliced operation. The ILC is focused on the highest gradients possible. FLASH accelerates beam at 5 Hz repetition rate. During accelerator studies the operation of the last accelerating modules with 10 Hz and alternating rf pulses has been established proving the feasibility of a time sliced operation at the XFEL. The rf pulses synchronous to the 5 Hz rf pulses are used for FEL operation whereas the gradient of the remaining rf pulse can be chosen independently and is used for long term high gradient operation gaining experience for the ILC. The operation of two different gradients within a single rf pulse is also available. The paper describes the technical setup, the rf control performance and the operational experience.

TUPP003	Automatic Generation of SEU Immunity for FPGA Based Electronics for Accelerators	controls, simulation, radiation, free-electron-laser	1529
	M. K. Grecki, G. W. Jablonski, W. Jalmuzna, D. R. Makowski TUL-DMCS, Łódź
	The modern accelerator control systems nowadays are build using digital technology based on FPGA circuits. However, digital circuits working in radioactive environment are exposed to disturbing effects, in particular SEU (Single Event Upset). One of the countermeasure is a redundancy in circuit that allow to detect and correct errors caused by radiation. Unfortunately CAD software provides no support to automatically include required redundancy in the FPGA project. Moreover, optimization procedure removes all redundant parts and special effort must be made to prevent that. The paper presents a software environment to process VHDL description of the circuit and automatically generate the redundant blocks together with voting circuits. The generated redundancy uses Triple Module Redundancy (TMR) scheme. It also supports the VHDL simulation with SEUs in order to enable identification of the most sensitive components*. Since the TMR is costly, the designer can indicate which parts of the circuit should be replicated based on the results of simulation. Baumann. Neutron-induced…, Int. Rel. Phys. Symp. 2000. Hentschke et al. Analyzing Area…, Symp. ICs and Systems Design, SBCCI02. *Grecki. VHDL Simulation…, Nanotech 2006, Vol.1.

TUPP033	Alternative Scheme of Bunch Length Compression in Linacs for Free Electron Lasers	damping, linac, simulation, bunching	1610
	S. Di Mitri, M. Cornacchia, S. V. Milton, S. Spampinati ELETTRA, Basovizza, Trieste
	The aim of this paper is to investigate the effect of an alternative scheme of bunch compression on the development of the microbunching instability. Two cases have been considered, one in the presence of a linear energy chirp at the compressor end and another without it. It is shown that after removing the linear energy chirp, a properly tuned R56 transport matrix element is able to dilute the initial energy modulation without affecting the bunch length and to damp the associated current spikes. A by-product of this study indicates that the global compression scheme can be further optimized in the direction of a double compression scheme in which the longitudinal Landau damping is enhanced by increasing the compression factor of the first compressor while reducing that of the second one. The limiting case of such a configuration is the single compression scheme at low energy. The study is based on analytical calculations and on the simulation code LiTrack.

TUPP034	Transverse Effects due to Vacuum Mirror of RF Gun	emittance, gun, simulation, vacuum	1613
	I. Zagorodnov, M. Dohlus, M. Krasilnikov DESY, Hamburg E. Gjonaj, S. Schnepp TEMF, Darmstadt
	The transverse kick due to the vacuum mirror in the RF gun can negatively affect the beam emittance. In this contribution we estimate numerically and analytically the transverse wake function of European XFEL RF gun and apply it in beam dynamics studies of the transverse phase space.

TUPP093	Crystalline Beam Simulations	ion, storage-ring, coupling, simulation	1747
	D. A. Krestnikov JINR/DLNP, Dubna, Moscow region M. Grieser MPI-K, Heidelberg M. Ikegami JAEA/Kansai, Kizu-machi Souraku-gun Kyoto-fu I. N. Meshkov, A. O. Sidorin, A. V. Smirnov, G. V. Trubnikov JINR, Dubna, Moscow Region M. Nakao, A. Noda, H. Souda, H. Tongu Kyoto ICR, Uji, Kyoto K. Noda, T. Shirai NIRS, Chiba-shi
	A new program code was elaborated for the simulation of crystalline beams on the S-LSR storage ring (Kyoto Univ., Japan) under action of the cooling system. For the investigation of ordered proton beams, which recently were observed in first time on S-LSR, a special molecular dynamics technique was used. This article presents results of the numerical simulation and comparison with experimental data.

TUPP112	The RADIOTHOMX Project	electron, photon, linac, gun	1785
	C. Bruni, F. Couchot, Y. Fedala, J. Haissinski, M. Lacroix, R. Roux, V. Variola, Z. F. Zomer LAL, Orsay N. Artemiev LOA, Palaiseau Ph. Balcou, E. Cormier, S. Montant, M. C. Nadeau CELIA, Talence JP. Brasile, A. S. Chauchat, C. Simonboisson THALES, Colombes R. Czarny Thales Laser SA, Orsay P. Gladkikh NSC/KIPT, Kharkov
	The goal of this project is to develop a compact device, which could produce an intense flux of monochromatic X-rays for medical applications. It is based on Compton back-scattering resulting from collisions between laser pulses and relativistic electron bunches. Intense laser beams can be obtained with a high gain Fabry-Perot cavity coupled with a high average power fiber laser. Such a scheme is going to be developed by CELIA and LAL laboratories. The accelerator design to produce high repetition rate electron bunches at 50 MeV is under study. Two possibilities are being investigated: either a linear accelerator combined with a storage ring operating at an injection frequency high enough to preserve the electron beam characteristics or a high average current ERL. Both accelerator configurations aiming at producing X-ray fluxes higher than 10¹² photons/s will be presented.

TUPP121	Spatial Resolution and Contrast of the Intensity Modulated Electron Beam by the Photocathode RF Gun for the Radiation Therapy	electron, gun, radiation, cathode	1809
	T. Kondoh, K. Kan, H. Kashima, K. Norizawa, A. Ogata, S. Tagawa, J. Yang, Y. Yoshida ISIR, Osaka
	The radiation therapy of cancer is developing to un-uniform irradiation as the Intensity Modulated Radiation Therapy (IMRT), for reduce dose to normal tissue. Toward the IMRT, optical modulation of electron beam is studying by a photocathode RF gun. The photocathode RF gun can generate a low emittance electron beam by laser light. Because of the low emittance beam, the modulated electron beam is able to accelerate keeping shape. Electron beam were monitored by CCD cameras measuring the luminescence of the scintillator. Fundamental data such as the spatial resolution and the contrast of the optical intensity modulated electron beam are necessary. Spatial Resolution and Contrast of the Intensity Modulated Electron Beam by a Photocathode RF Gun will be reported. If the shape of the modulated electron beam is different, it may not keep beam shape from the non-symmetrically of the repulsion of the bunch inside. It will be reported that the relations of the beam-shape and the keeping ability of beam.

TUPP155	Compact EUV Source Based on Laser Compton Scattering between Micro-bunched Electron Beam and CO2 Laser Pulse	electron, scattering, undulator, 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.

TUPP156	Development of a Compact X-ray Source Based on Laser-Compton Scattering with a Pulsed-laser Super-cavity	electron, photon, target, scattering	1872
	K. Sakaue, M. Washio RISE, Tokyo S. Araki, M. K. Fukuda, Y. Higashi, Y. Honda, T. Taniguchi, N. Terunuma, J. Urakawa KEK, Ibaraki N. Sasao Kyoto University, Kyoto
	A compact and high quality x-ray source is required for various fields, such as medical diagnosis, drug manifacturing and biological sciences. Laser-Compton based x-ray source that consists of a compact electron storage ring and a pulsed-laser super-cavity is one of the solutions of a compact x-ray source. Pulsed-laser super-cavity has been developed at KEK-ATF for a compact high brightness x-ray source. The pulsed-laser super-cavity enables to make high peak power and small waist laser at the collision point with the electron beam. Recently, 357MHz mode-locked Nd:VAN laser pulses can be stacked stably in a 420mm long Fabry-Perot cavity with 2.5kW average power in our R&D. On the other hand, we have succeeded to stack the pulsed amplified laser in the super-cavity. This indicates that the number of X-ray is multiplied due to the gain in the amplification system to synchronize the pulsed pump to the beam. In view of this successful result, we have started an X-ray generation experiment using a super-cavity and a multi-bunch electron beam at KEK-LUCX. Development of the super-cavity and the results of X-ray generation experiment will be presented at the conference.

TUPP158	Development of Laser System for Compact Laser Compton Scattering X-ray Source	electron, gun, scattering, linac	1878
	R. Kuroda, M. K. Koike, H. Toyokawa, K. Y. Yamada AIST, Tsukuba, Ibaraki T. Gowa, A. Masuda, K. Sakaue, M. Washio RISE, Tokyo S. Kashiwagi ISIR, Osaka T. Nakajyo, F. Sakai SHI, Tokyo
	A compact X-ray source via laser Compton scattering is required for biological, medical and industrial science because it has many benefits about generated X-rays such as short pulse, quasi-monochromatic, energy tunability and good directivity. Our X-ray source is conventionally the single collision system between an electron pulse and a laser pulse. To increase X-ray yield, we have developed a multi-collision system with a multi-bunch electron beam and a laser optical cavity. The multi-bunch beam will be generated from a Cs-Te photocathode rf gun sytem using a multi-pulse UV laser system. The laser optical cavity will be built like the regenerative amplification including the collision point between the electron pulse and the laser pulse to enhance the laser peak power per 1 collision on laser Compton scattering. In this conference, we will describe the results of preliminary experiments for the multi-collision system and future plans.

WEOBG04	First Experimental Results from DEGAS, the Quantum Limited Brightness Electron Source	electron, brightness, controls, feedback	1918
	M. S. Zolotorev, J. W. ONeill, F. Sannibale, W. Wan LBNL, Berkeley, California E. D. Commins, A. S. Tremsin UCB, Berkeley, California
	The construction of DEGAS (DEGenerate Advanced Source), a proof of principle for a quantum limited brightness electron source, has been completed at the Lawrence Berkeley National Laboratory. The commissioning and the characterization of this source, designed to generate coherent low energy (10-100 eV) single electron "bunches" with brightness approaching the quantum limit at a repetition rate of few MHz, has been started. In this paper the first experimental results are described.
	Slides

WEXM02	Status of the Linac Coherent Light Source	undulator, linac, electron, 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	undulator, electron, 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	undulator, 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

WEPC026	Laser – Beam Interaction and Calculation of the Sliced Bunch Radiation Spectra for the SLS FEMTO Beam Line	electron, wiggler, radiation, positron	2040
	D. K. Kalantaryan, G. A. Amatuni, V. M. Tsakanov CANDLE, Yerevan P. Beaud, G. Ingold, A. Streun PSI, Villigen
	The FEMTO insertion at the Swiss Light Source (SLS) produces sub-ps X-ray pulses by modulating the electron energy in a slice of the bunch through interaction with a fs-laser. The electron energy modulation by the laser field in the wiggler magnet is studied analytically to calculate the radiation spectra from a sliced bunch. The analytical expressions for energy modulation and its envelope have been derived. The radiation spectra in the first magnet after the FEMTO insertion have been studied. The spectra of the coherent part of the radiation are determined using a Fourier transformation technique. For a Gaussian bunch the obtained results are compared with the tracking simulation study.

WEPC028	Status of UVSOR-II and Light Source Developments	undulator, 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.

WEPC075	Recent Results and Future Perspectives of the SPARC Project	emittance, undulator, linac, 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.

WEPC105	Construction of a Cryogenic Permanent Magnet Undulator at ESRF	undulator, cryogenics, vacuum, simulation	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.

WEPC108	Portable Magnetic Field Measurement System	controls, vacuum, feedback, undulator	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.

WEPC112	The Acceptance and Photon Beam Formation in SLS FEMTO Beamline	radiation, background, electron, damping	2264
	L. M. Hovhannisyan, D. K. Kalantaryan, V. M. Tsakanov CANDLE, Yerevan S. T. Hakobyan YSU, Yerevan A. Streun PSI, Villigen
	The FEMTO insertion at the Swiss Light Source (SLS) produces sub-ps X-ray pulses by modulating the electron energy in a slice of the bunch through interaction with a fs-laser. The radiation from the sliced bunch in the FEMTO undulator of the SLS storage ring has been studied. Only photons passing all apertures of the beam line arrive at the experiment. We derive the transverse phase space distribution of these photons, the radiation spectra, and the spatial and angular distribution. Transmission of the radiated photons through the FEMTO beamline is calculated using the SRW simulation code in order to evaluate the acceptance of the beamline and the photon beam phase space distribution at the experimental station.

WEPC124	Magnetic Measurement System for the SPARC Insertion Devices	undulator, 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.

WEPC126	On a Biscuit Current Undulator	undulator, electron, 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.

WEPP077	The XFEL Laser Heater	undulator, 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.

WEPP078	PHIL: a Test Beam line at LAL	gun, simulation, vacuum, emittance	2698
	R. Roux, M. Bernard, G. Bienvenu, S. Cavalier, M. Jore, B. Leblond, B. M. Mercier, B. Mouton, C. P. Prevost, V. Variola LAL, Orsay
	For 2004, in the framework of a European contract, LAL is in charge of the construction of one photo-injector for the drive beam linac of the CLIC Test Facility 3 at CERN. This contract together with national funds allowed LAL to build a test accelerator with the same photo-injector as for CTF3. The goal is to undergo experiments on advanced RF guns but a part of the beam time will be also shared with users of the electron beam. So far, the construction of this accelerator at LAL was very much delayed because of the legal obligation to upgrade the radiation shielding in agreement with the actual radiation safety thresholds. The required civil engineering is now finished and the installation of the components is under way. We will first present a design of the accelerator and few dynamic simulation results. Finally we will give a status of the accelerator construction up to date.

WEPP082	Recirculator SALO Project in NSC KIPT	electron, injection, target, extraction	2710
	I. S. Guk, A. N. Dovbnya, S. G. Kononenko, F. A. Peev, A. S. Tarasenko NSC/KIPT, Kharkov J. I.M. Botman TUE, Eindhoven
	In NSC KIPT the electron recirculator project on energy up to 730 MeV is developing. The accelerator is designed first of all as a facility for basic research in the field of a nuclear physics. Superconducting accelerating structure TESLA on frequency of 1.3 GHz, developed in DESY, is used for a speed-up of electrons. Isochronous and achromatic system of injection and magneto-optical system recirculator arcs allow to gain good beam parameters on an exit of the accelerator. Channels of an extraction of particles on experimental stations are presented. Opportunities for use of recirculator beams for applied research are considered.

WEPP105	First Operation Results of the Superconducting Photoinjector at ELBE	gun, cathode, electron, diagnostics	2755
	J. Teichert, A. Arnold, A. Buechner, H. Buettig, D. Janssen, M. Justus, U. Lehnert, P. Michel, P. Murcek, R. Schurig, G. Staats, F. Staufenbiel, R. Xiang FZD, Dresden T. Kamps BESSY GmbH, Berlin G. Klemz, I. Will MBI, Berlin A. Matheisen DESY, Hamburg
	In November 2007 the first electron beam was generated from the superconducting RF photo electron gun installed at the ELBE linear accelerator facility. The injector together with a sophisticated laser system and a diagnostic beam line were developed and constructed within a collaboration of BESSY, DESY, MBI and FZD. Delivering a CW beam with up to 1 mA average current, a significant improvement of the beam quality like an increase of the bunch charge up to 1 nC and a reduced transverse emittance will be obtained. After the cool-down of the cryostat the RF properties of the 3½-cell niobium cavity like pass band mode frequencies, unloaded quality factor versus accelerating gradient, Lorentz force detuning, and He pressure influence were measured. The first beam was extracted of a Cu photo cathode using a 262 nm UV laser system with a repetition rate of 100 kHz and about 0.4 W laser power. Later, caesium telluride photo cathodes will be applied. The installed diagnostics allow beam current, energy, energy spread, transverse emittance and bunch length measurements of the beam. The results of these measurements and the operational experiences with the gun will be presented.

WEPP127	ALaDyn: a High Accuracy Code for the Laser-plasma Interaction	simulation, plasma, electron, acceleration	2794
	C. Benedetti, A. Sgattoni Bologna University, Bologna P. Tomassini INFN-Milano, Milano
	ALaDyn (Acceleration by LAser and DYNamics of charged particles) is a relativistic fully parallelized PIC code to investigate the interaction of a laser pulse with a plasma and/or an externally injected beam. The code is based on compact high order finite differences schemes ensuring higher spectral accuracy compared to standard Yee schemes. We present the main features and the performances of the code together with a set of validation tests obtained comparing the results with well-established analytical/numerical results. A preliminary benchmarking with the PIC code VORPAL is also presented. An application to a physically relevant case concerning the externally-injected configuration proposed for the CNR-INFN experiment PLASMONX will be analyzed.

WEPP134	Ultra-short x-ray Radiation coming from a Laser Wakefield Accelerator	electron, plasma, radiation, betatron	2809
	V. Leurent, L. Divol, T. Doeppner, D. H. Froula, S. H. Glenzer, P. Michel, J. Palastro LLNL, Livermore, California C. E. Clayton, C. Joshi, K. A. Marsh, A. E. Pak, J. E. Ralph, T.-L. Wang UCLA, Los Angeles, California B. B. Pollock, G. R. Tynan UCSD, La Jolla, California
	A Laser Wakefield Accelerator (LWFA) is under development at LLNL Jupiter Laser Facility to produce multi-GeV electron bunches promising to provide a bright and compact source of x-ray radiation for high energy density studies. The interaction of a high power (200 TW), short laser (50 fs) pulse with neutral He gas can accelerate monoenergetic electrons up to 1 GeV in a stable self-guiding regime, over a dephasing length of 1 cm (for a plasma density of 1.5x10¹⁸ cm^-3), overcoming the limitation of vacuum diffraction and allowing long interaction lengths for LWFA. The waveguide can be extended over several centimeters by using a novel scheme, which employs an external magnetic field (up to 5 T uniform along 12 cm) to control the radial heat flux* resulting from the interaction of a high energy (100 J), long pulse (1 ns) laser with a gas tube. The acceleration of electrons over several centimeters can produce multi-GeV bunches and thus a powerful x-ray source. Analysis will be presented on femtosecond x-ray radiation produced by wiggling an electron bunch with energy above 1 GeV in this new LWFA scheme. * W. Lu et al., Phys. Rev. Spec. Top-ac 10, 061301 (2007) ** D. H. Froula et al., Phys. Rev. Lett. 98, 135001 (2007)

WEPP136	Femtosecond and Attosecond Bunches of Electrons upon Field Emission in a Combined Quasi-static and Laser Electric Field	cathode, electron, radiation, single-bunch	2812
	V. A. Papadichev LPI, Moscow
	Obtaining short pulses of particles and of electromagnetic radiation is of interest for investigating fast processes in physics, chemistry, biology and medicine,. A new method of modulating an electron beam is proposed to obtain electron bunches of 100-as to 20-fs duration. For this purpose, two electric fields – quasi-static and the variable field of a laser with wavelength in the 0.25 – to 10 microns range – simultaneously act on a single-spiked or multi-spiked cathode. Current from 0.01 to 100 A from one spike having a curvature radius of 1 micron corresponds to a maximal intensity of total electric field of 70 to 280 MV/cm for a 10-micron laser wavelength. For a 1-micron laser, total fields of 300 – 400 MV/cm should be used for 1 – 20 A currents. A regime of device operation was determined for which the emitting surface of a copper cathode is not damaged. Obtaining a single bunch or a sequence of bunches with a repetition rate up to1330 THz was considered. Using multi-spiked cathodes permits to obtain bunches with current up to 10 kA. P. Emma. Issues and challenges for short pulse radiation production, Proc. EPAC04, p. 225, Lucerne, Suisse. **S. Rimjuem et al. Generation of femtosecond electron pulses, Proc. EPAC04, p. 431.

WEPP137	Accelerating and Transporting Attosecond and Femtosecond Bunches of Electrons	electron, cathode, space-charge, vacuum	2815
	V. A. Papadichev LPI, Moscow
	Dynamics of short bunches of electrons obtained upon field emission in a quasi-static electric field and a variable electric field of a laser has been studied. The equation of longitudinal motion of electrons was numerically integrated. Emitted electrons are accelerated by quasi-static potential applied to the spike and this drastically reduces initial energy spread in the bunch preventing its fast elongation. When the forces of space charge have little effect, grouping part of the beam due to velocity spread acquired in the laser field permits to obtain bunches of about 200-as duration when using a carbon dioxide laser and about 6-as with a neodymium laser. Analytical models were used to evaluate the influence of the space charge of the bunch on the longitudinal motion of electrons in it. It has been shown that the proper choice of the intensities of both fields can cancel such an influence. There have been considered methods of lateral focusing of the beam taking into account possible initial angular divergence and space charge effects. Such electron bunches could be used directly in experiments or for generation of short pulses of coherent UV- and X-ray radiation. V. A. Papadichev, Femtosecond and Attosecond Bunches of Electrons Upon Field Emission in a Combined Quasi-static and Laser Electric Field, submitted to this Conference.

WEPP138	Experimental Demonstration of Ultrashort μJ-Class Pulses in the Terahertz Regime from a Laser Wakefield Accelerator	radiation, electron, controls, plasma	2818
	G. R.D. Plateau, C. G.R. Geddes, N. H. Matlis, C. B. Schroeder, C. Toth, J. van Tilborg LBNL, Berkeley, California O. Albert LOA, Palaiseau E. Esarey, W. Leemans University of Nevada, Reno, Reno, Nevada
	Ultrashort terahertz pulses with energies in the μJ range can be generated with laser wakefield accelerators (LWFA), which are novel, compact accelerators that produce ultrashort electron bunches with energies up to 1 GeV* and energy spreads of a few-percent. Laser pulses interacting with a plasma create accelerated electrons which upon exiting the plasma emit terahertz pulses via transition radiation. Because they are only tens of femtoseconds long, electron bunches can radiate coherently (CTR) in a wide bandwidth (~ 1 - 10 THz) yielding terahertz pulses of high intensity,. In addition to providing a non-invasive bunch-length diagnostic*** and thus feedback for the LWFA, these high peak power THz pulses are suitable for high field (MV/cm) pump-probe experiments. Here we present energy-based measurements using a Golay cell and a single-shot electro-optic technique which were used to characterize the full waveform of these μJ-class THz pulses, including phase and amplitude information. W. P. Leemans et al. N. P. 2/696 (2006). W. P. Leemans et al. P. R.L. 91/074802 (2003). C. B. Schroeder et al. P. R.E 69/016501 (2004). **J. van Tilborg et al. P. R.L. 96/014801 (2006).

WEPP140	X-band PASER Experiment	acceleration, dipole, electron, resonance	2824
	A. Kanareykin, P. Schoessow Euclid TechLabs, LLC, Solon, Ohio S. P. Antipov ANL, Argonne, Illinois L. Schächter Technion, Haifa
	The PASER concept for particle acceleration entails the direct transfer of energy from an active medium to a charged particle beam. The PASER was originally formulated for optical (laser) media; we are pursuing a PASER demonstration experiment based on an optically pumped paramagnetic medium active in the X-band. We report on the development of a relatively high energy density microwave active medium consisting of a fullerene (C60) derivative in a toluene solution. We discuss both the bench test of an amplifier and a beam acceleration experiment under construction that employ this medium as a power source. Applications of the technology to accelerators and microwave components will be presented.

WEPP142	Simulation of and Progress towards a Micron-scale Laser-powered Dielectric Electron Source	simulation, vacuum, coupling, resonance	2827
	G. Travish, J. B. Rosenzweig, J. Xu UCLA, Los Angeles, California S. Boucher RadiaBeam, Marina del Rey R. B. Yoder Manhattan College, Riverdale, New York
	A dielectric, slab-symmetric structure for generating and accelerating low-energy electrons has been under study for the past two years. The resonant device is driven by a side-coupled laser and is configured to maintain field provide necessary for synchronous acceleration and focusing of nonrelativistic particles. Intended applications of the structure include the production of radiation for medical treatments, imaging, and industrial uses. The details of the structure geometry and its resonant properties have been studied with 2D and 3D electromagnetic codes, the results of which are present here.

WEPP146	Generation of Electron Microbunches Trains with Adjustable Sub-picosecond Spacing for PWFA and FEL applications	electron, plasma, quadrupole, emittance	2830
	P. Muggli, E. Kallos USC, Los Angeles, California M. Babzien, K. Kusche, V. Yakimenko BNL, Upton, Long Island, New York
	We demonstrate that trains of subpicosecond electron microbunches, with subpicosecond spacing, can be produced by placing a mask in a large dispersion region of the beam line where the beam transverse size is dominated by the correlated energy spread. The particles are selected based on the scattering of their emittance at the mask. The electrons that hit the solid arts of the mask are subsequently lost. The mask spatial pattern is converted into a time pattern in the dispersion-free region of the beam line. The experiment was performed with the Brookhaven National Laboratory Accelerator Test Facility 60 MeV beam. We show that the number, length, and spacing of the microbunches can be controlled through the parameters of the beam and the mask. Trains with one to eight equidistant microbunches are produced. The microbunches spacing is adjusted in the 100 to 300 microns or 300 fs to 1 ps range and comparable microbunch length. The train structure is measured using CTR interferometry, and is stable in time and energy. Such microbunch trains can be further compressed and accelerated, and have applications to free electron lasers (FELs) and plasma wakefield accelerators (PWFAs).

WEPP148	Generation of High Gradient Wakefields in Dielectric Loaded Structures	electron, gun, insertion, monitoring	2835
	M. E. Conde, S. P. Antipov, F. J. Franchini, W. Gai, F. Gao, R. Konecny, W. Liu, J. G. Power, Z. M. Yusof ANL, Argonne, Illinois C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio
	Dielectric loaded wakefield structures have potential to be used as high gradient accelerator components. Using the high current drive beam at the Argonne Wakefield Accelerator Facility, we employed cylindrical dielectric loaded wakefield structures to generate accelerating fields of up to 100 MV/m. Short electron bunches (13 ps FWHM) of up to 86 nC are used to drive these fields, either as single bunches or as bunch trains. These recently tested standing-wave structures have a field probe near the outer edge of the dielectric to sample the RF fields generated by the electron bunches. Monitoring of these high intensity RF fields serves to verify the absence of electric breakdown.

WEPP155	Laser Driven Linear Collider	acceleration, collider, plasma, damping	2850
	A. A. Mikhailichenko Cornell University, Department of Physics, Ithaca, New York
	We continue detailed description of scheme allowing long term acceleration with >10 GeV/m in multi-cell microstructures side-illuminated by laser radiation. The basis of the scheme is a fast sweeping device for the laser bunch. After sweeping the laser bunch has a slope ~45° with respect to the direction of propagation. So the every cell of microstructure becomes excited locally only for the moments, when the particles are there. Self consistent parameters of collider based on this idea allow consideration this type of collider as a candidate for the near-future accelerator era.

THPPGM02	EPS-AG 2008 Frank Sacherer Prize Presentation: First Steps Toward Laser Stripping Implementation	ion, polarization, linac, proton	2955
	V. V. Danilov ORNL, Oak Ridge, Tennessee
	Thin carbon foils are used as strippers for charge exchange injection into high intensity proton rings. However, the stripping foils become radioactive and produce uncontrolled beam loss, which is one of the main factors limiting beam power in high intensity proton rings. Recently, the first laser-assisted high efficiency conversion of H^- beam into protons was successfully demonstrated for a short laser pulse at Spallation Neutron Source project in Oak Ridge, Tennessee. The next step will be to build stripping device to make 1-10 μsec pulses stripping. The associated problems and possible solutions for projects with large ranges of H^- beam energies are described.
	Slides

THPC087	Electron Traps and Advanced Turbulence Diagnostic	electron, cathode, controls, diagnostics	3191
	M. Cavenago INFN/LNL, Legnaro, Padova G. Bettega, F. Cavaliere, R. Pozzoli, M. Rome INFN-Milano, Milano
	In the electron trap Eltrap both trapped and propagating beam (along the magnetic field axis z) up to 20 kV can be studied. Beam structures in x and y (transverse plane) were successfully detected. Main diagnostic and axial control of instabilities was based on electrostatic. The addition of an external electron source, controlled by a laser, makes ns electron bunches now possible. A system to dump the electron beam off axis is also described. Faster diagnostic and control methods can be tested. In particular, Thompson scattering diagnostic of beam structures can be tested, considering that a wavelength shift (even if modest) is present. Nonlinear dynamics modeling of injection process is also described.

THPC152	Electro-optic Bunch Arrival Time Measurement at FLASH	electron, diagnostics, acceleration, linac	3348
	V. R. Arsov, M. Felber, E.-A. Knabbe, F. Loehl, B. Lorbeer, F. Ludwig, K.-H. Matthiesen, H. Schlarb, B. Schmidt, P. Schmüser, S. Schulz, B. Steffen, A. Winter, J. Zemella DESY, Hamburg
	The operation of the next generation free electron lasers such as FLASH and the planned European XFEL requires drift free synchronization and femto-second stability. For this purpose an optical synchronization system has been developed, based on a mode-locked erbium-doped fiber laser, whose pulses are distributed over length stabilized fiber links. In order to evaluate the performance of the optical distribution system and the bunch arrival time monitors (BAM) an independent reference is needed. The measurement of the electro-optic (EO) response in a GaP crystal offers such a possibility. The method is destruction free and allows simultaneous determination of the peak current and the charge center of mass arrival time with femto-second precision. The measurements are performed with a 0.175 mm thick GaP crystal using 3 ps linearly chirped pulses from a Ti:Sa oscillator. The EO signal is encoded to the chirped pulse and spectrally resolved near crossed polarizers. Comparison of the EO and BAM timings provides a check of the relative accuracy of both methods, including the accuracy of the optical timing distribution system.

THPC156	Performances of the SPARC Laser and RF Synchronization Systems	linac, klystron, feedback, radiation	3354
	A. Gallo, D. Alesini, M. Bellaveglia, G. Gatti, C. Vicario INFN/LNF, Frascati (Roma)
	The SPARC project consists in a 150 MeV S-band, high-brilliance linac followed by 6 undulators for FEL radiation production at 530 nm. The linac assembly has been completed and the SPARC scientific program is presently in progress. The low level RF control electronics to monitor and synchronize the RF phase of the accelerating structures along the linac and the laser shot on the photocathode has been commissioned and it is now fully operative. The laser synchronization is routinely monitored and slow drifts are automatically corrected by a dedicated shot-to-shot feedback system. A similar slow automatic regulation is implemented on each linac accelerating section acting either on low level or high power sliding lines. The phase noise in the 2 RF power stations is counteracted by fast intra-pulse phase feedback systems that have been developed and put in operation. Phase stability measurements taken over the whole synchronization system are reported, and performances of different synchronization architectures, micro-wave based or laser based, are compared.

THPC157	A Simple Method for Timing an XFEL Source to High-power Lasers	undulator, electron, radiation, photon	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.

THPC158	Measurement and Stabilization of the Bunch Arrival Time at FLASH	feedback, controls, electron, acceleration	3360
	F. Loehl, V. R. Arsov, M. Felber, K. E. Hacker, B. Lorbeer, F. Ludwig, K.-H. Matthiesen, H. Schlarb, B. Schmidt DESY, Hamburg W. Jalmuzna TUL-DMCS, Łódź S. Schulz, A. Winter, J. Zemella Uni HH, Hamburg J. Szewinski The Andrzej Soltan Institute for Nuclear Studies, Centre Swierk, Swierk/Otwock
	To fully exploit the experimental opportunities offered by the 10 - 30 fs long light pulses from FLASH, e.g. in pump-probe experiments, precise measurements and control of the electron-bunch arrival-time on the 10 fs scale are needed. A bunch arrival time monitor (BAM) which uses the optical synchronization system of FLASH as a reference has been developed for this purpose. The bunch induced signal from a GHz-bandwidth beam pick-up is guided into an electro-optical modulator in which the periodic laser pulse train of the optical synchronization system experiences an amplitude modulation. Detection of this modulation allows to determine the bunch arrival time with a resolution of better than 20 fs. The superconducting linac of FLASH generates trains of up to 800 bunches. The BAM signals can be used for an intra-bunch train feedback stabilizing the arrival time to better than 50 fs. The feedback is capable of generating well-defined arrival time patterns within a bunch train which are useful for overlap-scans in pump-probe experiments. First results from the feedback installed at FLASH will be presented.

THPC160	An Optical Cross-correlation Scheme to Synchronize Distributed Laser Systems at FLASH	controls, diagnostics, polarization, electron	3366
	S. Schulz, V. R. Arsov, M. Felber, F. Loehl, B. Lorbeer, F. Ludwig, K.-H. Matthiesen, H. Schlarb, B. Schmidt, A. Winter DESY, Hamburg P. Schmüser, J. Zemella Uni HH, Hamburg B. Steffen PSI, Villigen
	The soft X-ray free-electron laser FLASH and the planned European XFEL generate X-ray light pulses in the femto-second range. For time-resolved pump-probe experiments, future operation modes by means of laser seeding and for special diagnostic measurements it is crucial to synchronize various laser systems to the electron beam with an accuracy better than 30 fs. For this purpose an optical synchronization system at the telecommunication wavelength of 1550 nm is currently being installed and tested at FLASH. We developed a background-free optical cross-correlation scheme to synchronize two mode-locked laser systems of different center wavelengths and repetition rates with an accuracy better than 10 fs. The scheme was tested by linking a commercial 81 MHz Ti:Sa oscillator (center wavelength 800 nm), used for electro-optical diagnostics at FLASH, to a locally installed 40.5 MHz erbium-doped fiber laser, operating at 1550 nm. Later, this laser will be replaced by an actively length-stabilized fiber-link distributing the pulses from the 216 MHz master laser oscillator of the machine to lock the diagnostics laser to the optical synchronization system.

THPP025	Fabrication Status of the PEFP DTL II	alignment, linac, proton, vacuum	3425
	H. S. Kim, Y.-S. Cho, J.-H. Jang, H.-J. Kwon, B.-S. Park KAERI, Daejon
	The DTL II as a main part of the PEFP proton linac is under development. Following the DTL I which accelerates the proton beam up to 20 MeV, DTL II increases the proton energy from 20 MeV to 100 MeV. The DTL II consists of 7 tanks and each tank is composed of 3 sections whose length is about 2.2 m. The tank is made of seamless carbon steel and inside surface is electroplated with copper. Each drift tube contains an electroquadrupole magnet which is made of hollow conductor and iron yoke with epoxy molding. The status of development and test results of the fabricated parts are reported in this paper.

THPP050	Recent Status of Laser Cooling for Mg Realized at S-LSR	ion, coupling, synchrotron, electron	3476
	A. Noda, M. Ikegami, T. Ishikawa, M. Nakao, T. Shirai, H. Souda, M. Tanabe, H. Tongu, A. Wakita Kyoto ICR, Uji, Kyoto M. Grieser MPI-K, Heidelberg I. N. Meshkov, A. V. Smirnov JINR, Dubna, Moscow Region K. Noda NIRS, Chiba-shi
	At an ion storage and cooler ring, S-LSR, a laser cooling has been applied to the 40 keV ²⁴Mg⁺ ion beam guiding a laser with the wave length of 280nm parallel to the ion beam together with the deceleration by an induction voltage. Up to now, the longitudinal temperature has been cooled down to 3.6 Kelvin for the ion number of 3x10⁴ although the transverse one still remains around 500 Kelvin. The longitudinal temperature is limited by the heat transfer from the transverse degree of freedom through intra-beam scattering, which becomes stronger according to increase of ion number. It is found that the equilibrium longitudinal temperature is linearly coupled with the transverse one* for our experimental condition up to now. In the present paper, recent experimental data will be presented together with the procedure of beam diagnosis with the use of optical methods using a spontaneous emission of the Mg ions. Possible approach to realize the resonant coupling through synchro-betatron coupling** is also to be presented. * M. Tanabe et al., To be published in Applied Physics Express (APEX). ** Okamoto, A. M. Sessler, D Möhl, Phys. Rev. Lett. 72 (1994)3977.

THPP054	Laser Cooling of Bunched Ion Beam at S-LSR	synchrotron	3488
	H. Souda, M. Ikegami, T. Ishikawa, M. Nakao, A. Noda, T. Shirai, M. Tanabe, H. Tongu, A. Wakita, M. Yamada Kyoto ICR, Uji, Kyoto
	S-LSR is an ion storage ring equipped with an electron cooler and a laser cooling system. The laser cooling experiments of coasting beams were carried out during last year. Now we started bunched beam laser cooling. 40keV Mg+ beams are bunched by an untuned RF cavity for harmonic number 5-50, and is cooled by a single 280nm laser. Bunch length are measured by electrostatic pickups. When RF harmonic number is five, bunch lengths is shorten from 1m to under 0.14m by laser cooling. Since the bunch length after cooling is shorter than present monitor resolution, fluorescence measurement is in preparation. We have installed another small RF cavity for harmonic number 100. Synchrotron-betatron coupling will be induced by dispersion at the place of this cavity. This effect is expected to realize three dimensional laser cooling. In this paper we present the result of bunched beam cooling and the trial to three dimensional laser cooling. M. Tanabe et al. Appl. Phys. Express, in press. **H. Okamoto. Phys. Rev. E 50, 4982 (1994).

FRXCGM01	High Quality GeV Electron Beams from Plasma-Laser Accelerators	electron, synchrotron, free-electron-laser, plasma	3733
	W. Leemans LBNL, Berkeley, California
	Accelerators are essential tools of discovery and have many practical uses. At the forefront of accelerator technology are the machines that deliver beams for particle physics, for synchrotron and free electron based radiation sources. The technology that drives these accelerators is extremely sophisticated but is limited by the maximum sustainable accelerating field. This impacts the size and cost of the device. More than two decades ago, lasers were proposed as power source for driving novel accelerators based on plasmas as the accelerating medium. An overview will be presented of what these devices can produce to date, including the 2004 demonstration of high quality electron beams* and the 2006 demonstration of GeV class beams from a 3 cm long accelerating structure*. We then discuss the key challenges for broad applicability of the technology and our goal of making a laser accelerator driven a VUV/soft x-ray free electron laser. C. G.R. Geddes et al., Nature 431, 538-541 (2004); S. P.D. Mangles et al., ibidem, p.535-538; J. Faure et al., ibidem, p. 541-544. ** W. P. Leemans et al., Nature Physics 2, 696-699 (2006).
	Slides