EPAC08 - List of Keywords (electron)

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electron

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

MOZAG02	Short Bunches in Electron Storage Rings and Coherent Synchrotron Radiation	radiation, storage-ring, optics, synchrotron	26
	G. Wuestefeld BESSY GmbH, Berlin
	Significant progress has been made in recent years in achieving short bunches in third generation synchrotron light sources and the generation of coherent radiation. This talk will review the properties of the radiation and the associated beam dynamics, and will discuss optics issues and the limits of the available techniques.
	Slides

MOZBM01	High Intensity and Low Emittance Guns	gun, cathode, laser, 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, linac, laser, free-electron-laser	61
	A. Aksoy, Ö. Karsli, B. Ketenoglu, O. Yavas Ankara University, Faculty of Engineering, Tandogan, Ankara A. K. Ciftci, Z. Nergiz Ankara University, Faculty of Sciences, Tandogan/Ankara E. Kasap Gazi University, Faculty of Science and Arts, Ankara
	Turkish Accelerator Complex (TAC) Infrared Free Electron Laser (IR-FEL) project was approved by State Planning Organization (DPT) as a first step of the national project. The facility will consist of 15 40 MeV superconducting electron linac and two different optical cavity systems with different undulator period length to obtain FEL in 2 185 microns wavelengths range. In this study, the results of optimization and current status of TAC IR FEL facility is presented. The facility will give opportunity to search applications in material science, biotechnology, nonlinear optics, semiconductors, medicine and chemistry using IR-FEL in Turkey and our region.

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

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

MOPC004	First Results from the Upgraded PITZ Facility	gun, laser, diagnostics, 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, laser, brilliance	73
	M.-E. Couprie, M. Labat CEA, Gif-sur-Yvette C. Benabderrahmane, O. V. Chubar, G. Lambert, A. Loulergue, O. Marcouillé SOLEIL, Gif-sur-Yvette C. Bruni LAL, Orsay L. Giannessi ENEA C. R. Frascati, Frascati (Roma)
	The ARC-EN-CIEL project proposes a panoply of light sources for the scientific community on a 1 GeV superconducting LINAC (phase 2) on which two ERL loops (1 and 2 GeV) are added in phase 3. LEL1 (200-1.5 nm), LEL2 (10-0.5 nm) and LEL4 (2-0.2 nm) are three kHz High Gain Harmonic Generation Free Electron Laser sources seeded with the High order Harmonics generated in Gas, with 100-30 FWHM pulses. A collaboration, which has been set-up with the SCSS Prototype Accelerator in Japan for test this key concept of ARC-EN-CIEL, has led to the experimental demonstration of the seeding with HHG and the observation up the 7th non linear harmonic with a seed at 160 nm. Besides. LEL3 (40-8 nm) installed on the 1 GeV loop is a MHz FEL oscillator providing higher average power and brilliance. In addition, in vacuum undulator spontaneous emission source extend the spectral range above 10 keV and intense THz radiation is generated by edge radiation of bending magnets. Optimisations and light sources characteristics are described.

MOPC006	Seeding of the Test FEL at MAX-lab	laser, 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.

MOPC010	Injector System for X-ray FEL at SPring-8	emittance, gun, bunching, linac	85
	H. Hanaki, T. Asaka, H. Ego, H. Kimura, T. Kobayashi, S. Suzuki JASRI/SPring-8, Hyogo-ken T. Hara, A. Higashiya, T. Inagaki, N. Kumagai, H. Maesaka, Y. Otake, T. Shintake, H. Tanaka, K. Togawa RIKEN/SPring-8, Hyogo
	The SPring-8 X-FEL based on the SASE process has been developed to generate X-rays of 0.1 nm by the combination of an 8 GeV high gradient linac (400 m) and a mini-gap undulator of in-vacuum type (90 m). The design goals of the slice beam emittance and peak current at the end of the linac are 1 π mm mrad and 3 kA, respectively. The injector of the linac generates an electron beam of 1 nC, accelerates it up to 30 MeV, and compresses its bunch length down to 20 ps step by step. The injector has been designed on the basis of the SCSS test accelerator. We adopted the following keys to toward the goals: A 500 kV thermionic gun (CeB6) without a control grid ejecting a beam holding the low rms emittance of 1.1 π mm mrad, a beam deflector downstream gating the beam to form a bunch of a 1 ns length, multi-stage RF structures (238, 476 and 1428 MHz) bunching and accelerating the beam gradually to maintain the initial emittance, and extra RF cavities of 1428 and 5712 MHz linearizing the energy chirp of the beam bunch to achieve the bunch compression resulting the required peak current.

MOPC011	Improvement and Recent Results of the DELTA Storage Ring FEL	laser, 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.

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

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

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

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

MOPC019	Velocity Bunching at FLASH	emittance, bunching, simulation, gun	112
	T. Limberg, B. Beutner, W. Decking, M. Huening, M. Krasilnikov, M. Vogt DESY, Hamburg O. Grimm Uni HH, Hamburg
	The vacuum-ultra-violet free electron laser in Hamburg (FLASH) is a linac driven SASE-FEL. High peak currents are, in routine operation, produced using magnetic bunch compression chicanes. Longitudinal dispersion in these chicanes allow bunch length changes of relativistic electron beams. For low energy electron beams (~5 MeV), the velocity dependence on electron energy can be utilized for bunch compression. Since strong bunch compression at low beam energies gives rise to strong space charge interactions which has an impact on, for instance, beam emittance and is therefore not suitable for full compression to the kA peak currents needed for SASE operation. Moderate velocity bunching, however, might be used to optimize the total bunch compression system of FLASH or the European XFEL. Experiments on the velocity bunching process at FLASH are presented here. Results on bunch length and transverse emittance measurements are discussed and compared with numerical tracking calculations.

MOPC024	Calculation of Coherent Synchrotron Radiation in General Particle Tracer	space-charge, shielding, emittance, synchrotron	118
	I. V. Bazarov Cornell University, Department of Physics, Ithaca, New York T. Miyajima KEK, Ibaraki
	General Particle Tracer (GPT) is a particle tracking code, which includes 3D space charge effect based on nonequidistant multigrid Poisson solver or point-to-point method. It is used to investigate beam dynamics in ERL and FEL injectors. We have developed a new routine to simulate coherent synchrotron radiation (CSR) in GPT based on the formalism of Sagan. The routine can calculate 1D-wake functions for arbitrary beam trajectories as well as CSR shielding effect. In particular, the CSR routine does not assume ultrarelativistic electron beam and is therefore applicable at low beam energies in the injector. Energy loss and energy spread caused by CSR effect were checked for a simple circular orbit, and compared with analytic formulas. In addition, we enhanced the 3D space charge routine in GPT to obtain more accurate results in bending magnets. D. Sagan, EPAC06, pp. 2829-2831.

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

MOPC027	A Fast Switching Mirror Chamber for FLASH	feedback, laser, radiation, 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	undulator, radiation, laser, photon	127
	H. Schlarb, S. Düsterer, J. Feldhaus, T. Laarmann DESY, Hamburg A. Azima, J. Boedewadt, H. Delsim-Hashemi, M. Drescher, S. Khan, Th. Maltezopoulos, V. Miltchev, M. Mittenzwey, J. Rossbach, R. Tarkeshian, M. Wieland Uni HH, Hamburg
	Since 2004, the free-electron laser FLASH at DESY has operated in the Self-Amplified Stimulated Emission mode, delivering to users photon beams with wavelengths between 6.5 nm and 40 nm. In 2009, DESY plans to install a 3.9 GHz RF acceleration section for the production of electron bunches with high peak currents (~kA), but ten times larger pulse durations (~250 fs) compared to the present configuration. The relaxed timing requirements of the new configuration make it possible to externally seed FLASH with high harmonics of an optical laser (sFLASH). The aim of the project is to study the technical feasibility of seeding an FEL at 30 nm with a stability suited for user operation. sFLASH will use 10 m of gap-tunable undulators installed in front of the fixed gap SASE-undulator. A chicane behind the seeding undulators will allow to extract the output radiation for a careful characterisation and for first pump-probe experiments with a resolution in the 10 fs range by combining FEL and seed laser pulses.

MOPC029	Longitudinal Structure of Electron Bunches at the Micrometer Scale from Spectroscopy of Coherent Transition Radiation	radiation, linac, collective-effects, space-charge	130
	B. Schmidt, C. Behrens, S. Wesch DESY, Hamburg H. Delsim-Hashemi, J. Rossbach, P. Schmüser Uni HH, Hamburg
	At the free electron laser FLASH in Hamburg, a longitudinal bunch compression scheme is used resulting in a longitudinal current profile with a narrow leading spike. Part of this spike is responsible for producing high-intensity short FEL pulses via the SASE process. The width and the structure of the current spike, which are key parameters for the efficiency of the SASE process, are barely accessible to direct measurements in the time domain. Using an infrared multi-stage grating spectrometer, we have studied the spectral composition of coherent transition radiation from single electron bunches. The data show that the 'fundamental width' of the current spike is about 40 fs (fwhm) with prominent substructures down to the 10 fs scale. The intensity fluctuations of coherent radiation in the corresponding wavelength range are strongly correlated to the fluctuations of the FEL pulse energy. Extension of the method to the near infrared regime have revealed micro-structures with characteristic lengths from a few micrometers down to fractions of a micrometer. Their interrelation with the parameters of the electron beam and the compression system have been studied.

MOPC030	Operation of FLASH at 6.5 nm Wavelength	radiation, laser, gun, 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.

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

MOPC032	Progress of the Commissioning of the Test FEL at MAX-lab	laser, gun, simulation, 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, laser, 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	emittance, laser, 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	laser, emittance, simulation, 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, laser, 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	laser, 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	laser, 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	laser, 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	laser, emittance, cathode, 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	laser, photon, background, single-bunch	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, storage-ring, laser, 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.

MOPC048	Coherent Synchrotron Radiation Burst from Electron Storage Ring under External RF Modulation	radiation, synchrotron, synchrotron-radiation, storage-ring	178
	Y. Shoji NewSUBARU/SPring-8, Laboratory of Advanced Science and Technology for Industry (LASTI), Hyogo T. Takahashi KURRI, Osaka
	It is known that a high-peak-current beam in an electron storage ring emits a burst of coherent synchrotron radiation (CSR) in the THz region. This CSR is powerful and easily obtained with no special expense, but is not used by synchrotron radiation users. This is because the burst arises from a fine time structure in the bunch due to longitudinal beam instabilities, and is unstable. We quantitatively investigated its time structure to find out how unstable it is. The measurements of CSR from one bunch showed that with an average period of 10ms (comparable with the damping time, 12 ms) the fluctuation of averaged power was about 10%. This would be reduced to 1% with 100 bunches. The fluctuation ratio had small dependence on beam charge, rf acceleration voltage and momentum compaction factor. The successive bursts had a correlation because the beam had a memory of former bursts. This worked to reduce the fluctuation in long period. When the rf phase was modulated with 2fs (twice of the synchrotron oscillation frequency), the burst structure was modulated with 2fs and the long term fluctuation was reduced. This modulation can be used to eliminate background noise in user experiments.

MOPC049	Comparative Study of Vibration Stability at Operating Light Source Facilities and Lessons Learned in Achieving NSLS II Stability Goals	site, ground-motion, lattice, storage-ring	181
	N. Simos, M. Fallier BNL, Upton, Long Island, New York H. Amick Colin Gordon, Associates, San Bruno
	Understanding the correlation between storage ring vibration and electron beam oscillation is key in achieving the design beam parameters of a 3rd generation light source. Spectral properties of the vibration at the storage ring floor, in addition to amplitude, and its relation to the dynamic properties of the lattice govern the complex relation between lattice movement and beam jitter. Spectral characteristics are, in general, site-specific and motions exhibit spatial variability. To best describe the relationship between the ground motion field at the NSLS II site and the accelerator while quantifying the storage ring oscillations resulting from its interaction with the undisturbed site, field studies have been conducted at various light source facilities. By using the same metric data characterizing the achieved stability levels in operating light sources are generated and used in the assessment of the NSLS II stability which in turn linked to the specific site, subsurface and design characteristics. The paper summarizes the results of these comprehensive findings and presents an overall assessment of stability levels that can be achieved. Work performed under the auspices of the US DOE.

MOPC053	BEAM DYNAMICS IN THE LASER-ELECTRON STORAGE RING FOR A COMPTON X-RAY SOURCE	laser, 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.

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

MOPC057	R&D Energy Recovery Linac at Brookhaven National Laboratory	gun, linac, klystron, diagnostics	193
	V. Litvinenko, D. Beavis, I. Ben-Zvi, M. Blaskiewicz, A. Burrill, R. Calaga, P. Cameron, X. Chang, K. A. Drees, G. Ganetis, D. M. Gassner, H. Hahn, L. R. Hammons, A. Hershcovitch, H.-C. Hseuh, A. K. Jain, A. Kayran, J. Kewisch, R. F. Lambiase, D. L. Lederle, G. J. Mahler, G. T. McIntyre, W. Meng, T. C. Nehring, B. Oerter, C. Pai, D. Pate, D. Phillips, E. Pozdeyev, T. Rao, J. Reich, T. Roser, T. Russo, K. Smith, J. E. Tuozzolo, D. Weiss, N. Williams, K. Yip, A. Zaltsman BNL, Upton, Long Island, New York H. Bluem, M. D. Cole, A. J. Favale, D. Holmes, J. Rathke, T. Schultheiss AES, Medford, NY J. R. Delayen, L. W. Funk, H. L. Phillips, J. P. Preble Jefferson Lab, Newport News, Virginia
	Collider Accelerator Department at BNL is in the final stages of developing the 20-MeV R&D energy recovery linac with super-conducting 2.5 MeV RF gun and single-mode super-conducting 5-cell RF linac. This unique facility aims to address many outstanding questions relevant for high current (up to 0.5 A of average current), high brightness energy-recovery linacs with novel Zigzag-type merger. We present the performance of the R&D ERL elements and detailed commissioning plan.

MOPC061	Progress in R&D Efforts on the Energy Recovery Linac in Japan	linac, laser, gun, 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, laser, gun	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	laser, emittance, 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.

MOPC065	Wake Field Simulations for Structures of the PITZ RF Photoinjector: Emittance growth estimations	emittance, simulation, diagnostics, gun	217
	E. Arevalo, W. Ackermann, E. Gjonaj, W. F.O. Müller, S. Schnepp, T. Weiland TEMF, Darmstadt
	One of the main concerns in the design of electron guns is the generation of low-emittance beams. One source of emittance growth is the beam-surrounding effect, which can be estimated from the wake potentials along the beam path. For the calculation of these potentials an accurate knowledge of the short range wake fields induced in the different parts of the gun with geometrical discontinuities is necessary. The computation of these wake fields is a challenging problem, as an accurate resolution for both the small bunch and the large model geometry is needed. Here with the help of numerical wake-potential calculations we analytically estimate the emittance growth for the RF electron gun of the Photoninjector Test Facility at DESY Zeuthen (PITZ).

MOPC067	Normal Conducting CW RF Gun Design for High Performance Electron Beams	gun, cathode, emittance, simulation	223
	H. Bluem, T. Schultheiss, L. M. Young AES, Medford, NY R. A. Rimmer Jefferson Lab, Newport News, Virginia
	High repetition rate (>1 MHz), high charge (1 nC), low emittance (1 micron) electron beams are an important enabling technology for next generation light sources. Advanced Energy Systems has begun the development of an advanced, continuous-wave, normal-conducting radio frequency electron gun. This gun is designed to minimize thermal stress, allowing fabrication in copper, while providing low emittance electron beams. Beam dynamics performance will be presented along with thermal and stress analysis of the gun cavity design.

MOPC071	Development of a High Brightness Photo-Injector for Light Source Research at NSRRC	gun, laser, 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, laser, photon	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	gun, vacuum, cathode, laser	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.

MOPC074	3D Simulations of a Non-axisymmetric High Average Current DC Photocathode Electron Gun	cathode, gun, simulation, ion	238
	J. W. McKenzie, B. L. Militsyn STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
	At high average currents, GaAs photocathode based electron guns are limited by the short operational lifetime of the photocathodes. One method to improve the cathode lifetime is to situate the photocathode off-axis to reduce the flow of ions back-bombarding the emitting surface. The results of 3D electrostatic and beam dynamic simulations are presented to demonstrate the feasibility of this scheme and the resultant beam quality achievable.

MOPC078	Tuning and Conditioning of a New High Gradient Gun Cavity at PITZ	gun, emittance, cathode, controls	244
	S. Rimjaem, G. Asova, J. W. Baehr, C. H. Boulware, H.-J. Grabosch, M. Hänel, Ye. Ivanisenko, M. Krasilnikov, S. Lederer, A. Oppelt, B. Petrosyan, T. A. Scholz, A. Shapovalov, R. Spesyvtsev, L. Staykov, F. Stephan DESY Zeuthen, Zeuthen K. Floettmann, D. Reschke DESY, Hamburg L. Hakobyan YerPhI, Yerevan R. Richter BESSY GmbH, Berlin J. Roensch Uni HH, Hamburg
	A new 1.3 GHz photo cathode electron gun (prototype 4.2) for the Photo Injector Test facility in Zeuthen (PITZ) was tuned in February 2007. The main difference in the mechanical design compared to earlier guns is a significantly improved cooling system. This gun is also the first copper gun cavity where a particle free cleaning using dry ice technique was applied while in the previous guns the high pressure ultra pure water rinsing technique was used. The cavity has been installed in a new Conditioning Test Stand (CTS) at PITZ in autumn 2007. It has been conditioned to an accelerating gradient of 60 MV/m and more. Dark current measurements have been performed to monitor the improvement of conditioning and to compare with the results from the previous guns. In this paper, RF measurement and tuning results as well as results of the conditioning and dark current measurements will be presented and discussed.

MOPC080	Status of the FERMI@Elettra Photoinjector	gun, laser, 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.

MOPC088	High Power Neutron Converter for Low Energy Proton/Deuteron Beams: Test Facility	target, controls, gun, vacuum	265
	V. Gubin, A. V. Antoshin, M. S. Avilov, M. F. Blinov, D. Bolkhovityanov, V. A. Golikov, M. A. Kholopov, N. N. Lebedev, P. V. Logachev, V. S. Popov, S. V. Shiyankov, A. S. Tsyganov, I. E. Zhul BINP SB RAS, Novosibirsk
	This paper presents conceptual design of test facility, that is now under creation in the framework of development of high power neutron targets for SPES (INFN-LNL, Italy) and SPIRAL-II (GANIL, France). General destination of facility is to test different target systems and elements (hot converter unit, liquid metal driving gear and cooling systems) as well as experimental checking of supply, protection and control methods etc. Also, this facility must be used as a base for input quality control of targets as a whole in future. The structure, general features and experimental possibilities of facility are described.

MOPC089	About Carbides-made Nanoceramics Fission Target for RIB Production	target, extraction, ion, ion-source	268
	V. Gubin, M. Golkovsky BINP SB RAS, Novosibirsk O. Alyakrinsky INFN/LNL, Legnaro, Padova S. P. Bardakhanov SB RAS Khristianovich Institute of Theoretical and Applied Mechanics, Novosibirsk
	Intensities of RIBs can be increased with improvement of release efficiency of fission targets. One of factor, which limits release efficiency of targets, is efficiency of release of isotopes from target material. This paper presents investigation of dependence of release efficiency from ceramics target on its grain size and inter-grains pores, as well shows some efficiency limits and ways to improve it. Simulations were performed for uniform target material made from powder of uranium carbide. Inter-grain spaces are taken relative to grain sizes, as another parameter to optimize is high density of target material. Results show that optimal grain size is in the range of hundreds - thousands nanometers, while recent target materials utilize one order more sizes of grains. In addition, key points of production of such ceramics are discussed. The beam technologies allow producing the nanopowders from carbides of different metals with controlled grain size. Exact methods also give to us possibilities to obtain ceramics with optimal ratio between grain and pores sizes. Possible problems and preliminary program of experiments and tests are discussed.

MOPC094	Irradiation Effects on the Physio-mechanical Properties of Super-alloys Characterized by Low Thermal Expansion	proton, target, photon, radiation	283
	N. Simos, H. G. Kirk BNL, Upton, Long Island, New York K. T. McDonald PU, Princeton, New Jersey N. V. Mokhov Fermilab, Batavia, Illinois
	In an effort to address the limitations on high power accelerator target performance prompted by the elevated dose levels and the associated irradiation damage, an experimental study has been undertaken to evaluate the potential applicability of super alloys characterized by low thermal expansion over certain thermal regimes. The intriguing properties associated with materials such as super-Invar and the “gum” metal (Ti-12Ta-9Nb-3V-6Zr-O) are observed in their un-irradiated state. Irradiations were performed using the 200 MeV protons of the BNL Linac and/or a neutron flux generated by the stopping of the primary 112 MeV protons upstream of the exposed super-alloys. The paper presents the post-irradiation analysis results which reveal interesting damage reversal by the super-invar and unexpected low threshold of radiation resistance by the “gum” metal. Work performed under the auspices of the US DOE.

MOPC098	LHC Particle Collimation by Hollow Electron Beams	collimation, proton, cathode, ion	292
	V. D. Shiltsev, A. I. Drozhdin, V. Kamerdzhiev, G. F. Kuznetsov, L. G. Vorobiev Fermilab, Batavia, Illinois
	Electron Lenses built and installed in Tevatron have proven themselves as safe and very reliable instruments which can be effectively used in hadron collider operation for a number of applications, including compensation of beam- beam effects, DC beam removal from abort gaps, as a diagnostic tool. In this presentation we consider a possibility of using electron lenses with hollow electron beam for ion and proton collimation in LHC.

MOPC099	Ion Catcher System for the Stabilisation of the Dynamic Pressure in SIS18	ion, beam-losses, vacuum, controls	295
	C. Omet, H. Kollmus, H. Reich-Sprenger, P. J. Spiller GSI, Darmstadt
	In synchrotrons operated with intermediate charge state heavy ion beams, intensity dependent beam losses have been observed. The origin of these losses is the change of charge state of the beam ions at collisions with residual gas atoms. The resulting m/q deviation from the reference beam ion leads to modified trajectories in dispersive elements, which finally results in beam loss. At the impact on the beam pipe, gas molecules are released by ion stimulated desorption which increase the vacuum pressure locally. In turn, this pressure rise will enhance the charge change- and particle loss process and finally cause significant beam loss within a very short time. In order to suppress and control the gas desorption process, a dedicated ion catcher system incorporating NEG coated surfaces and low-desorption rate materials has been developed and two prototypes were installed in SIS18. The design of the scraper and measured effect on the dynamic residual gas pressure are presented.

MOPC106	Injection and Acceleration of Au³¹⁺ in the BNL AGS	ion, injection, vacuum, acceleration	313
	W. Fischer, L. Ahrens, K. A. Brown, C. J. Gardner, J. W. Glenn, H. Huang, M. Mapes, J. Morris, V. Schoefer, L. Smart, P. Thieberger, N. Tsoupas, K. L. Unger, K. Zeno, S. Y. Zhang BNL, Upton, Long Island, New York C. Omet, P. J. Spiller GSI, Darmstadt
	Injection and acceleration of ions in a lower charge state reduces space charge effects, and, if further electron stripping is needed, may allow elimination of a stripping stage and the associated beam losses. The former is of interest to the accelerators of the GSI FAIR complex, the latter for BNL RHIC collider operation at energies lower than the current injection energy. Lower charge state ions, however, have a higher likelihood of electron stripping which can lead to dynamic pressures rises and subsequent beam losses. We report on experiments in the AGS where Au³¹⁺ ions were injected and accelerated instead of the normally used Au⁷⁷⁺ ions. Beam intensities and the average pressure in the AGS ring are recorded, and compared with calculations for dynamic pressures and beam losses. The experimental results will be used to benchmark the STRAHLSIM dynamic vacuum code and will be incorporated in the GSI FAIR SIS100 design.

MOPC112	HESR Linear Lattice Design	target, lattice, antiproton, betatron	325
	B. Lorentz, A. Lehrach, R. Maier, D. Prasuhn, H. Stockhorst, R. Tölle FZJ, Jülich
	The High Energy Storage Ring (HESR) is a part of the future Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. The ring is used for hadron physics experiments with a pellet target and the PANDA detector, and will supply antiprotons of momenta from 1.5 GeV/c to 15 GeV/c. The ring will consist of two 180 degree bending sections (arcs) of 157 m length, each, and two 132 m long straight sections. In one of the straight sections the PANDA experiment will be installed, the other straight section will be equipped with a High Energy Electron Cooler. A longitudinal and transverse stochastic cooling system will be used in the momentum range from 3.8 GeV/c to 15 GeV/c. Adjustment of beta functions at target and electron cooler, to achieve highest beam lifetimes, most efficient cooling and highest luminosities are the main design requirements. The basic design consists of FODO cell structures in the arcs. The arc quadrupole magnets are grouped into four families, to allow a flexible adjustment of transition energy, horizontal and vertical tune, and dispersion. The details of the linear lattice and operation modes will be discussed in this presentation.

MOPC113	Head-on Beam-beam Compensation with Electron Lenses in the Relativistic Heavy Ion Collider	proton, emittance, simulation, resonance	328
	Y. Luo, N. P. Abreu, E. N. Beebe, J. Beebe-Wang, C. Montag, M. Okamura, A. I. Pikin, G. Robert-Demolaize BNL, Upton, Long Island, New York
	The working points for polarized proton operation in the Relativistic Heavy Ion Collider (RHIC) are currently constrained between 2/3 and 7/10, and the beam and luminosity lifetimes are limited by head-on beam-beam effects. To further increase the bunch intensity, we propose a low energy Gaussian electron beam, or electron lens, to collide head-on with the proton beam in order to compensate the large tune shift and tune spread generated by the proton-proton collisions in 2 interaction points. In this article, outline of the RHIC head-on beam-beam compensation with e-lenses and parameters for both proton and electron beams are presented.

MOPC114	Status of the Electrostatic and Cryogenic Double Ring DESIREE	ion, vacuum, storage-ring, proton	331
	P. Löfgren, G. Andler, L. Bagge, M. Björkhage, M. Blom, H. Danared, A. Källberg, S. Leontein, L. Liljeby, A. Paal, K.-G. Rensfelt, A. Simonsson MSL, Stockholm H. Cederquist, M. Larsson, S. Rosén, H. T. Schmidt Stockholm University, Department of Physics, Stockholm
	DESIREE is a double electrostatic storage ring being built at the Manne Siegbahn Laboratory and Stockholm University. The two rings in DESIREE have the same circumference, 8.7m, and a common straight section along which stored ions can interact. The ion optics for both rings will be housed in a single double walled vacuum chamber built like a cryostat with a radiation screen and several layers of super insulation in between the two chambers. The inner chamber, which holds all the optical elements, will be cooled by four cryogenerators attached to the bottom of this chamber. It is constructed in pure aluminum to ensure good thermal conductivity over the whole structure. The whole accelerator structure will be cooled below 20K. This low temperature in combination with the unique double ring structure will result in a powerful machine for studying interactions between cold molecular ions close to zero relative energy. The outer vacuum chamber is constructed in steel with a high magnetic permeability to provide an efficient screening of the earth magnetic field. DESIREE will be provided with two injectors which will be able to supply both positive and negative ions to both rings.

MOPC123	Lattice Study for the Carbon Ion Synchrotron forTherapy with Electron Cooling	ion, extraction, synchrotron, septum	355
	S. V. Sinyatkin, V. A. Kiselev, E. B. Levichev, V. V. Parkhomchuk, V. B. Reva, V. A. Vostrikov BINP SB RAS, Novosibirsk
	In this paper the preliminary design of magnet lattice of the Carbon Ion Therapy Facility with electron cooling is described. The influence of misalignments of magnetic elements on ring parameters and the layout of orbit correction are estimated. The different methods of ion extractions from the synchrotron are considered, i.e., the pellet extraction, recombination extraction and the extraction on the sextupole resonance.

MOPC135	Present Status and Future improvement of HIRFL-CSR	ion, target, heavy-ion, injection	388
	Y. J. Yuan, J. W. Xia, W.-L. Zhan, H. W. Zhao IMP, Lanzhou
	The HIRFL-CSR project is a national mega project of China, which concentrates on heavy ion synchrotron and cooling storage ring. It is finished recently. The present commissioning results, testing experiments are introduced in this paper. The future improvement of the machine is also shown.

MOPC137	The Cryogenic Storage Ring Project at Heidelberg	ion, cryogenics, vacuum, storage-ring	394
	R. von Hahn, K. Blaum, J. R. Crespo López-Urrutia, M. W. Froese, M. Grieser, M. Lange, F. Laux, S. Menk, D. Orlov, R. Repnow, C. D. Schroeter, D. Schwalm, T. Sieber, J. Ullrich, J. Varju, A. Wolf MPI-K, Heidelberg H. Quack TU Dresden, Dresden M. Rappaport, D. Zajfman Weizmann Institute of Science, Physics, Rehovot X. Urbain UCL CRC, Louvain-la-Neuve
	At the Max-Planck-Institut für Kernphysik in Heidelberg a next generation electrostatic storage ring at cryogenic temperatures is under development. The main perspective of this unique cryogenic storage ring (CSR) is the research on ions, molecules and clusters up to bio molecules in the energy range of 20 keV -300 keV at low temperatures down to 2 Kelvin. The achievement of this low temperature for all material walls seen by the ions in the storage ring not only causes a strong reduction of black body radiation incident onto the stored particles, but also acts as a large cryopump, expected to achieve a vacuum of better than 1·10^-15 mbar (corresponding to 1·10^-13 mbar room temperature äquivalent). The low temperature and the extreme low vacuum will allow novel experiments to be performed, such as rotational and vibrational state control of molecular ions and their interaction with ultra-low energy electrons and laser radiation. A 20 W at 2 K refrigerator was designed and successfully commissioned. A connection with the fully assembled cryogenic prototype ion trap is under way. In this paper the concept and the status of the cryogenic storage ring will be presented.

MOPC139	Refractory Ovens for ECR Ion Sources and Their Scaling	plasma, ion, ion-source, resonance	397
	M. Cavenago, A. Galatà, M. Sattin INFN/LNL, Legnaro, Padova T. Kulevoy, S. Petrenko ITEP, Moscow
	The radiofrequency (rf) oven can be used as a metal vapour injector for Electron Cyclotron Resonance ion source; the application to high temperature boiling metals (like Cr, Ti and V) was recently demonstrated. Duration and reusability of oven parts were excellent, since crucible only need to be maintained at a temperature Ts larger than other parts; for vanadium case, achieved Ts was up to 2300 K with about 280 W of rf power, with the present design and size, tailored to our 14.4 GHz ECRIS. Optimization for different sources is discussed, and modern design tools are reviewed. Materials, more than rf power coupling, emerge as ultimate limits. Comparisons of results with resistive oven and sputter probes and with different metals are briefly reported.

MOPC141	Design of a Novel Tubular Electron String Ion Source (TESIS)	ion, extraction, ion-source, gun	403
	E. Syresin, D. E. Donets, E. D. Donets, E. E. Donets, V. B. Shutov JINR, Dubna, Moscow Region V. M. Drobin, A. V. Shabunov, Yu. A. Shishov JINR/LHE, Moscow A. E. Dubinov, R. M. Garipov, I. V. Makarov VNIIEF, Sarov (Nizhnii Gorod) L. Liljeby MSL, Stockholm
	The project, started in 2007 is directed to creation of Tubular Electron String Ion Source (TESIS) and to basic studies of electron strings in tubular geometry. The collaboration consists of JINR (Dubna) and Russian Federal Nuclear Center (Sarov, Russia), Manne Siegbahn Laboratory (Stockholm, Sweden), TRIUMF and Atomic Energy of Canada Ltd. (Canada). Tubular concept of ion source has been proposed few years ago. Preliminary theoretical estimations and numerical simulations have been done,** that allowed to start experimental realization of this project. New tubular source with a superconducting solenoid up to 5 Tesla should be constructed in 2009. It is expected that this new TESIS (“Krion-T1”) will meet all rigid conceptual and technological requirements and should provide ion output on a level, approaching to 10 mA of Ar¹⁶⁺ ions in the pulse mode and about 10 mA of Ar¹⁶⁺ ions in the average current mode. Having these output parameters, “Krion-T1” TESIS should be an operational prototype of further TESIS sources for all kinds of the possible applications. Simulation results and a basic scetch of the TESIS construction will be presented. Donets E. D. et al. Rev. Sci. Instrum. 73, 696 (2002). Donets E. D., Donets E. E., Becker R. et al. Rev. Sci. Instrum.75, 1566 (2004). **Donets E. E. J. of Phys.: Conf. Series 2, 97 (2004).

MOPD003	ILC Cavity Fabrication Optimization for High Production	factory, vacuum, radio-frequency, linear-collider	451
	A. J. Favale, M. Calderaro, E. Peterson, J. J. Sredniawski AES, Medford, NY
	In 2006, AES performed a US based industrial Cost Study of RF units in production quantities sufficient for the ILC. During this study detailed costs were estimated for the fabrication steps of the SRF cavities in high production quantities. In late 2007, AES carried out a more detailed study specifically oriented toward optimizing the high production methods of only the SRF cavities to arrive at a best estimate of cost. We have found that the revised estimate shows a 34% reduction in cavity fabrication cost. We have optimized many of the machining and welding steps to take advantage of automated operations were possible. Our high production cost estimates were based upon actual machining, welding and parts handling times derived during the prototype fabrication of ILC type cavities at AES. These values were then applied with learning as appropriate to more automated operations to reduce labor costs. In addition, the type and size of e-beam welding machines was optimized. We found that the use of all single chamber welders covering three specific sizes was most cost effective. Details of steps leading to the stated conclusions are presented herein.

MOPD004	CPI RF Components for the ILC	klystron, vacuum, gun, controls	454
	T. A. Treado, S. J. Einarson, T. W. Habermann CPI, Beverley, Massachusetts
	Communications & Power Industries, Inc. (CPI) has active programs to refine key components for the European XFEL. These components, the fundamental power coupler and the multibeam klystron (MBK) are also suited for the International Linear Collider (ILC). CPI power couplers are manufactured to our customer's specifications using processes which are standard to the electron device industry as well as processes which are specific to power couplers. We have developed the capability of plating high-RRR copper on stainless steel. We have developed the capability of applying TiN coatings to ceramic windows. Both processes are done in-house under carefully controlled conditions. Both processes have been fully qualified. CPI has manufactured nearly 100 power couplers of various designs. Our presentation will focus on power couplers for the XFEL and the ILC. CPI is currently developing a second-generation, horizontal MBK for DESY. This MBK operates at 10 MW, at an RF frequency of 1.3 GHz, 1.5 ms pulse length, and 10 Hz pulse repetition rate. Our presentation will provide an update on this development program.

MOPD015	Current Status of Development in TETD of High-power Vacuum Microwave Devices	klystron, linac, proton, power-supply	475
	M. Niigaki Toshiba Electron Tubes & Devices Co., Ltd, Tokyo K. Hayashi, M. Irikura, M. Sakamoto, H. Taoka TETD, Otawara M. Y. Miyake, Y. Okubo, S. Sakamoto, Y. Yano Toshiba Electron Tubes & Devices Co., Ltd (TETD), Tochigi
	TETD (Toshiba Electron Tubes & Devices Co., LTD.) has been developing a wide variety of klystrons and input couplers in collaboration with some Japanese research institutes. This article presents recent results of the development including a C-band and an S-band pulsed klystrons for SPring-8 Joint Project for XFEL, 1.3-GHz horizontal MBK for DESY and a 1.3-GHz TTF-type input coupler for the European XFEL. As an application to fusion experimental devices, development of a 5-GHz, 500-kW CW klystron for KSTAR and a 170-GHz quasi CW gyrotron for ITER are also presented.

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

MOPD023	Parametric Study of a Novel Coaxial Bunched Beam Space-charge Limit	space-charge, plasma, focusing, klystron	493
	M. Hess IUCF, Bloomington, Indiana
	Recently, a non-trivial space-charge limit for off-axis bunched electron beams in a coaxial conducting structure was derived theoretically. The space-charge limit describes the minimum strength of an external solenoidal focusing field which is needed to stabilize the beam’s center-of-mass motion in the presence of induced surface charges on the coaxial structure. In this paper, we perform a parametric study of the space-charge limit to numerically determine its dependency on the conducting structure geometry, i.e., the ratio of the inner and outer conductor radii, as well as its’ dependency on the transverse and longitudinal bunch distributions. As an application, we show how this parametric study can be important for the design of high-power microwave sources, such as the UC-Davis/SLAC 2.8 GHz coaxial ubitron oscillator. M. Hess, accepted for publication in IEEE Trans. Plasma Sci. (2008). **A. J. Balkcum et al. IEEE Trans. Plasma Sci., vol. 26, pp. 548-555, 1998.

MOPD025	Status of the 805-MHz Pulsed Klystrons for the Spallation Neutron Source	klystron, cathode, gun, factory	499
	S. Lenci, E. L. Eisen CPI, Palo Alto, California M. P. McCarthy ORNL, Oak Ridge, Tennessee
	Communications and Power Industries, Inc (CPI) produced 81 klystrons for the Spallation Neutron Source at Oak Ridge National Laboratory. The klystrons are rated for 550 kW peak at 805 MHz. Seventy units have accumulated 1.2M hours of filament operation and 820K hours of high voltage operation through January 2008. A higher power 700 kW version has been developed and is now in production with 12 of the 38 units on order delivered through January 2008. Performance specifications, computer model predictions, operating results, production statistics, and operational status will be presented.

MOPD027	AMC-based Radiation Monitoring System	radiation, monitoring, controls, power-supply	505
	D. R. Makowski, A. Napieralski, A. Piotrowski TUL-DMCS, Łódź S. Simrock DESY, Hamburg
	This paper reports a novel radiation monitoring system able to monitor gamma and neutron radiation in an accelerator tunnel in the nearest proximity of the electronic components of the control system. The monitoring system is designed as an Advanced Mezzanine Module (AMC) and it is dedicated for the Low Level Radio Frequency (LLRF) control system based on the Advanced Telecommunication Computing Architecture (ATCA). The AMC module is able to communicate with LLRF control system using both I2C interface defined by Intelligent Platform Management Interface (IPMI) standard and PCI Express. The measured gamma radiation dose and neutron fluence are sent to data acquisition computer using Ethernet network and stored in a database. Static Random Access Memory (SRAM) is applied as a neutron dosimeter. The principle of the detector is based on the radiation effect initiating the Single Event Upsets (SEUs) in a high density microelectronic SRAMs. A well known RadFET dosimeter is used to monitor gamma radiation.

MOPD029	Commissioning of the 2,2 kW, 476 MHz Solid State RF Power Source for the LNLS Booster Synchrotron	booster, synchrotron, injection, storage-ring	511
	C. Pardine, R. H.A. Farias, P. F. Tavares LNLS, Campinas
	A 2.2 kW, 476 MHz unconditionally stable solid state RF amplifier for CW operation has been built, tested, and is being used since july 2007 at LNLS. The amplifier, designed and developed in collaboration with Synchrotron SOLEIL, is made of 9 modules, each one containing one push-pull 290 W MOSFET equipped with an internal circulator and RF load. Low cost, reliability, linearity and high efficiency are the main features we aimed for in this device, which was developed for the LNLS Booster Injector. In this paper, we present technical characteristics as well as test results of the system.

MOPD035	20 MW Pulse Amplifier Klystron with Multiple Frequency Two-Gap Bunching Resonators for Linear Electron Accelerators	klystron, bunching, focusing, vacuum	529
	K. G. Simonov, A. N. Korolev, A. V. Mamontov ISTOK, Moscow Region
	A klystron design with a two-gap bunching resonator which provides interaction with electron beam by fields of multiple frequencies of two-gap resonator fundamental oscillations for increasing the klystron efficiency is being considered. At that the two-gap resonator is tuned to antiphased oscillation at operating frequency and to in-phase oscillation at the second harmonic. Such choice of frequency oscillation types allows to make the resonator compact and provide optimal conditions for electron beam interaction with microwave fields of the two-gap resonator both in antiphased and in-phase oscillation types. The relations for choosing two-gap resonator interaction area size providing a stable klystron operation without self-excitation are given. The compactness of the realized two-gap resonator with multiple frequencies allowed to locate it into klystron drift tube between the main resonators without increasing the klystron overall dimensions. The results of experimental research of klystron with such a two-gap resonator showed a possibility to increase its efficiency significantly.

MOPD042	Design and Testing of the Horizontal Version of the Multi Beam Klystron for European XFEL Project	klystron, cathode, gun, linac	544
	Y. Yano, M. Y. Miyake, Y. Okubo, S. Sakamoto Toshiba Electron Tubes & Devices Co., Ltd (TETD), Tochigi Y. H. Chin KEK, Ibaraki K. Hayashi, K. Tetsuka, H. Urakata TETD, Otawara
	Toshiba Electron Tubes & Devices (TETD) has been developing 10-MW L-band Multi-Beam Klystrons (MBKs) for the European XFEL project and possibly for future linear colliders. In order to allow horizontal installation in the XFEL tunnel, the horizontal version of MBK, MBK E3736H, has been designed, fabricated and tested by TETD. The MBK has six low-perveance beams operated at low voltage of less than 120 kV (for 10MW) and six ring-shaped cavities. In the successful acceptance testing at TETD in August 2007, the MBK achieved an output power of 10.3 MW at the beam voltage of 117 kV and at the RF pulse width of 1.5ms with efficiency of 67%. This test demonstrated that MBK E3736H fulfills all the requirements necessary as the RF power source of the XFEL linac.

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

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

MOPP036	Dark Current Model for ILC Main Linac	linac, simulation, quadrupole, focusing	625
	N. Solyak, N. V. Mokhov, G. V. Romanov Fermilab, Batavia, Illinois Y. I. Eidelman BINP SB RAS, Novosibirsk W. M. Tam IUCF, Bloomington, Indiana
	In the ILC Main Linac the dark current electrons, generated in SRF cavity can be accelerated to hundreds of MeV before being kicked out by quadrupoles and thus will originate electromagnetic cascade showers in the surrounding materials. Some of the shower secondaries can return back into vacuum and re-accelerated again. The results of simulation of the dark current dynamics and energy deposition along the linac are discussed in paper.

MOPP044	Cavity Diagnostic System for the Vertical Test of the STF Baseline 9-cell Cavity at KEK	monitoring, controls, diagnostics, survey	643
	Y. Yamamoto, H. Hayano, E. Kako, S. Noguchi, M. Satoh, T. Shishido, K. Umemori, K. Watanabe KEK, Ibaraki S.-I. Moon POSTECH, Pohang, Kyungbuk H. Sakai, K. Shinoe ISSP/SRL, Chiba Q. J. Xu IHEP Beijing, Beijing
	Four 9-cell cavities, which are TESLA-type 9-cell cavities, were developed and tested in KEK for the future ILC project. A simple cavity diagnostic system was introduced to search the heating spot and to detect the x-ray emission. It is composed of the carbon resistors and the PIN photo diodes. They were attached on the equator of the cell, around the HOM couplers and on the end flanges. They were very effective to search the heating spot and to detect the x-ray emission during the vertical tests. All cavities eventually had the heating spot around the equator in the final state of the vertical test. It is conceivable that the quality of the electron beam welding was somewhat poor, when the dumbbells were connected. On this February, a new vertical test facility will be completed in STF (Superconducting RF Test Facility). Six 9-cell cavities will be tested by using the new system for S0 plan, which goal is the higher accelerating gradient for ILC. The new temperature and x-ray mapping system and new DAQ system will be introduced. This paper reports the recent status in the new vertical test facility in KEK-STF.

MOPP048	Fast Ion Instability in the CLIC Transfer Line and Main Linac	ion, linac, vacuum, emittance	655
	G. Rumolo, D. Schulte CERN, Geneva
	The Fast Ion Instability is believed to be a serious danger for bunch trains propagating in the CLIC electron transfer line and main linac, since it may strongly affect the bunches in the tail of the train if the vacuum pressure is not below a certain threshold. We have developed the FASTION code, which can track electrons through a FODO cell line and takes into account their interactions with the produced (and possibly trapped) ions. We describe how this tool can be used for setting tolerances on the vacuum pressure and for giving specifications for the design of a feedback system.

MOPP050	Electron Cloud Build Up and Instability in the CLIC Damping Rings	wiggler, simulation, damping, positron	661
	G. Rumolo, Y. Papaphilippou CERN, Geneva W. Bruns WBFB, Berlin
	Electron cloud can be formed in the CLIC positron damping ring and cause intolerable tune shift and beam instability. 2D and 3D build up simulations with the Faktor2 code, developed at CERN, have been done to predict the cloud formation in the arcs and wigglers of the damping rings. HEADTAIL simulations have been used to study the effect of this electron cloud on the beam and assess the thresholds above which the electron cloud instability would set in.

MOPP057	ILC DR Vacuum Design and E-cloud	vacuum, photon, positron, dipole	673
	O. B. Malyshev STFC/DL/ASTeC, Daresbury, Warrington, Cheshire W. Bruns WBFB, Berlin
	An electron cloud parameters and vacuum design are tightly bounded to each other. Input parameters for the e-cloud depend on shape of vacuum chamber and surface property (material, roughthness, coatings, etc.), electron multipacting in the vacuum chamber causes the electron stimulated gas desorption and may require modification of vacuum system to deal with it. This paper describes the e-cloud modelling performed in a way to optimise ILC DR vacuum design in positron ring and to have clear understanding what modification in vacuum chamber are required. Three parameters of e-cloud were varied in turn: photo-electron emission, secondary electron yield and gas pressure. It was found all three parameter should not exceed certain value to keep the e-cloud density to an acceptable level. The energy and intensity of electron bombardment of the vacuum chamber walls and electron stimulated gas desorption were also calculated. It was found that electron stimulated gas desorption is comparable or larger than the photon stimulated desorption and should be considered in vacuum design.

MOPP059	Study for ILC Damping Ring at KEKB	emittance, damping, optics, sextupole	676
	K. Ohmi, J. W. Flanagan, H. Fukuma, K.-I. Kanazawa, H. Koiso, M. Masuzawa, Y. Ohnishi, K. Oide, Y. Suetsugu, M. Tobiyama KEK, Ibaraki M. T.F. Pivi SLAC, Menlo Park, California
	ILC damping ring consists of very low emittance electron and positron storage rings. It is necessary for ILC damping ring to study electron cloud effects in such low emittance positron ring. We propose a low emittance operation of KEKB to study the effects.

MOPP063	A New Chicane Experiment in PEP-II to Test Mitigations of the Electron Cloud Effect for Linear Colliders	dipole, resonance, simulation, vacuum	688
	M. T.F. Pivi, D. Arnett, F. D. Cooper, D. Kharakh, F. King, R. E. Kirby, B. Kuekan, J. J. Lipari, M. Munro, J. S.T. Ng, J. Olszewski, T. O. Raubenheimer, J. Seeman, B. Smith, C. M. Spencer, L. Wang, W. Wittmer SLAC, Menlo Park, California C. M. Celata, M. A. Furman LBNL, Berkeley, California
	Beam instability caused by the electron cloud has been observed in positron and proton storage rings and it is expected to be a limiting factor in the performance of the positron Damping Ring (DR) of future Linear Colliders such as ILC and CLIC. Possible remedies for the electron cloud effect include thin-film coatings, surface conditioning, antechamber, clearing electrodes, and chamber with grooves or slots. The effect is expected to be particularly severe in magnetic field regions. To test this and possible mitigation methods, we have installed a new 4-dipole chicane experiment in the PEP-II Low Energy Ring (LER). We have also installed test chambers in straight field free regions. The associated chamber consists of bare aluminum and TiN-coated inner surface sections. Each section is instrumented with arrays of readout electrodes and retarding grids. Installation of a grooved chamber is also planned. In this paper, we describe the ongoing R&D effort at SLAC to reduce the electron cloud effect in linear colliders. We present the design of the chicane, the chambers and diagnostics, as well as the experimental results obtained.

MOPP064	Secondary Electron Yield Measurements and Groove Chambers Update Tests in the PEP-II Beam Line	vacuum, simulation, storage-ring, positron	691
	M. T.F. Pivi, F. King, R. E. Kirby, T. W. Markiewicz, T. O. Raubenheimer, J. Seeman, L. Wang SLAC, Menlo Park, California
	In the Low Energy Ring (LER) of the PEP-II accelerator, we have installed vacuum chambers with rectangular grooves in straight sections to test this possible mitigation technique for the electron cloud effect in the positron damping ring (DR) of the future Linear Colliders such as ILC and CLIC. We have also installed chambers to monitor the secondary electron yield (SEY) of TiN, TiZrV (NEG) and technical accelerator materials under the effect of electron and photon conditioning in situ. Furthermore, we have also installed test chambers in a new 4-magnet chicane. We describe the ongoing R&D effort to mitigate the electron cloud effect in the ILC damping ring, the chambers installation in the PEP-II and latest results.

MOPP065	Microwave Transmission Measurement of the Electron Cloud Density in the Positron Ring of PEP-II	dipole, plasma, vacuum, simulation	694
	M. T.F. Pivi, A. Krasnykh SLAC, Menlo Park, California J. M. Byrd, S. De Santis, K. G. Sonnad LBNL, Berkeley, California F. Caspers, T. Kroyer, F. Roncarolo CERN, Geneva
	Clouds of low energy electrons in the vacuum beam pipes of accelerators of positively charged particle beams present a serious limitation for operation of these machines at high currents. Because of the size of these accelerators, it is difficult to probe the low energy electron clouds over substantial lengths of the beam pipe. We have developed a novel technique to directly measure the electron cloud density via the phase shift induced in a TE wave which is independently excited and transmitted over a section of the accelerator. We infer the absolute phase shift with relatively high accuracy from the phase modulation of the transmission due to the modulation of the electron cloud density from a gap in the positively charged beam. We have used this technique for the first time to measure the average electron cloud density over a 50 m straight section in the positron ring of the PEP-II collider at the Stanford Linear Accelerator Center. We have also measured the variation of the density by using low field solenoid magnets to control the electrons.

MOPP068	Simulation Study of Fast Ion Instability in the ILC Damping Ring	damping, feedback, ion, simulation	703
	G. X. Xia, Eckhard. Elsen DESY, Hamburg
	The so-called fast ion instability potentially constitutes a performance limitation for the damping ring of the International Linear Collider (ILC). Based on the latest baseline lattice of the ILC damping ring the fast ion instability is simulated using a weak-strong code. Various fill patterns are examined to mitigate the onset of the instability. Feedback mechanisms are explored. The growth time of the fast ion instability is estimated for various vacuum pressures on the basis of the simulated results.

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

MOPP074	Improvement of an S-band RF-gun cavity with a Cs-Te Photo-cathode	cathode, impedance, scattering, resonance	721
	A. Murata, Y. Hama, T. Hirose, Y. Kato, K. Sakaue, T. Suzuki, M. Washio RISE, Tokyo H. Hayano, N. Kudoh, T. T. Takatomi, N. Terunuma, J. Urakawa KEK, Ibaraki Y. Kamiya University of Tokyo, Tokyo S. Kashiwagi ISIR, Osaka M. Kuriki Hiroshima University, Graduate School of Science, Higashi-Hiroshima R. Kuroda AIST, Tsukuba, Ibaraki
	A 1.6cell S-band photo-cathode RF-Gun is one of the good alternatives of the short pulse electron source. Therefore,we are operating as a high brightness short pulse electron source for studying a reaction of radiation chemistry,an inverse Compton scattering at Waseda University and as an injector at KEK-ATF. To improve an electron beam quality and to reduce a dark current,we decided to improve the RF-Gun cavity. Frequency tuning of the half cell of existing RF-gun was performed by the torque control of Helicoflex seal on the cathode plate and two moving rod type tuners were installed on the full cell. Newly designed RF-Gun cavity has four compact tuners on each cell,which can be tune the frequency to deform the cavity wall,to remove the Helicoflex seal and tuning holes that were considered to be the major cause of electric discharge and/or a dark current source. According to these improvements,the Q-value and shunt impedance of the cavity is 30% larger than that of existing guns. As the result,the reduction of dark current is succeeded and the beam energy is reached up to 5.5MeV at 10MW RF input. The detailed results of electron beam generation will be reported at the conference.

MOPP075	Experimental Generation and Characterization of Uniformly Filled Ellipsoidal Electron Beam Distributions	laser, 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	laser, 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.

MOPP080	Studies of Breakdown in a Pressurized RF Cavity	simulation, ion, emittance, collider	736
	M. BastaniNejad, A. A. Elmustafa Old Dominion University, Norfolk, Virginia M. Alsharo'a, P. M. Hanlet, R. P. Johnson, S. Korenev, M. Kuchnir, D. J. Newsham, R. Sah Muons, Inc, Batavia C. M. Ankenbrandt, A. Moretti, M. Popovic, K. Yonehara Fermilab, Batavia, Illinois D. M. Kaplan Illinois Institute of Technology, Chicago, Illinois D. Li LBNL, Berkeley, California D. Rose, C. H. Thoma, D. R. Welch Voss Scientific, Albuquerque, New Mexico
	Previous studies of RF breakdown in a cavity pressurized with dense hydrogen gas have indicated that breakdown probability is proportional to a high power of the surface electromagnetic field. This behavior is similar to the Fowler-Nordheim description of electron emission from a cold cathode, and it implies that breakdown is a quantum mechanical effect that is characterized by the work function of the cavity metal. We describe our present efforts to measure the distributions of work functions at the nanoscale level on the surfaces of the electrodes used in breakdown studies, and to understand how the RF conditioning process affects them.

MOPP083	Status of High Power Tests of Normal Conducting Single-cell Structures	impedance, klystron, vacuum, damping	742
	V. A. Dolgashev, S. G. Tantawi SLAC, Menlo Park, California Y. Higashi, T. Higo KEK, Ibaraki
	We report results of ongoing high power tests of single cell traveling wave and standing wave structures. These tests are part of an experimental and theoretical study of rf breakdown in normal conducting structures at 11.4 GHz. The goal of this study is to determine the gradient potential of normal-conducting, rf powered particle beam accelerators. The test setup consists of reusable mode launchers and short test structures and powered by SLAC’s XL-4 klystron. The mode launchers and structures were manufactured at SLAC and KEK and tested in SLAC klystron test laboratory. V. A. Dolgashev, S. G. Tantawi, et al. “High Power Tests of Normal Conducting Single Cell Structures,” SLAC-PUB-12956, PAC07, Albuquerque, New Mexico, 25-29 June 2007, pp 2430-2432.

MOPP085	Bench Characterization of a Prototype of a 3rd Harmonic Cavity for the LNLS Electron Storage Ring	impedance, storage-ring, synchrotron, controls	748
	R. H.A. Farias, D. A. Nascimento, C. Pardine, P. F. Tavares LNLS, Campinas
	The UVX electron storage ring at the Brazilian Synchrotron Light Laboratory suffers from longitudinal instabilities driven by a HOM of one of the RF cavities. The operational difficulties related to these unstable modes were successfully overcome by determining the proper cavity temperature set point in combination with phase modulation of the RF fields at the second harmonic of the synchrotron frequency. However, a serious drawback of the method is to increase the energy spread of the electron beam, which is detrimental for the undulator emission spectrum. The use of higher harmonic cavities is a more appropriate technique since it provides damping of the longitudinal modes without increasing the energy spread. A full scale prototype of a 3rd harmonic cavity was manufactured at the LNLS workshops and had its main rf properties measured. Special care was taken to measure the shunt impedance of the fundamental resonant mode since it determines how many cavities will be necessary for the adequate operation of the system, which is designed to operate in passive mode. In this work we present the results of the bench characterization of the cavity.

MOPP086	A Novel Fabrication Technique for the Production of RF Photoinjectors	gun, vacuum, controls, coupling	751
	P. Frigola, R. B. Agustsson, S. Boucher, A. Y. Murokh RadiaBeam, Los Angeles D. Cormier, T. Mahale NCSU, Raleigh L. Faillace Rome University La Sapienza, Roma J. B. Rosenzweig, G. Travish UCLA, Los Angeles, California
	Recent developments in Direct Metal Free Form Fabrication (DMFFF) technology may make it possible to design and produce near netshape copper structures for the next generation of very high duty factor, high gradient radio frequency (RF) photoinjectors. RF and thermal-management optimized geometries could be fully realized without the usual constraints and compromises of conventional machining techniques. A photoinjector design incorporating DMFFF and results from an initial material feasibility study will be reported.

MOPP087	RF System for the SSRF Booster Synchrotron	booster, synchrotron, injection, extraction	754
	Q. Gu, L. X. Chen, M. Chen, L. Feng, Z. Q. Feng, H. T. Hou, J. F. Liu, C. Luo, D. Q. Mao, F. Wang, Zh. G. Zhang, S. J. Zhao, Y. B. Zhao, Z. S. Zhou SINAP, Shanghai
	The booster synchrotron of the Shanghai Synchrotron Radiation Facility (SSRF) ramps the energy of electron beam from 150 MeV to 3.5 GeV with a repetition rate of 2 Hz. The guidelines of the system design are simplicity and reliability, and the ability of top-up injection for the storage ring is also taking into account. The RF system consists of a 180kW CW plant with a WR1800 waveguide line, two PETRA type 5-cell cavities and an analog low level RF electronics with vector-sum scheme. An overview, installation and commissioning of the whole booster RF system are presented in this paper. The performance of the RF system with the beam is also given.

MOPP088	The High Harmonics Cavity System for the New Experimental Storage Ring at FAIR	coupling, impedance, bunching, emittance	757
	R. G. Heine, C. Dimopoulou, U. Laier GSI, Darmstadt
	The "Facility for Antiproton and Ion Research" (FAIR) will consist of several synchrotrons and storage rings dedicated to target experiments as well as in-situ experiments. One of the in-situ experiments is ELISe, a head-on collision of a heavy ion beam in the new experimental storage ring(NESR) with an electron beam prepared in the electron ring (ER). The vertex is placed in a bypass to the NESR where both rings have a common straight section. To prepare the heavy ion beam for collision with the bunched electron beam circulating at a fixed repetition rate a dedicated RF system called high harmonics cavity system (HHC) operating at a frequency of 44.7MHz is needed. The HHC will be realised as a disk loaded coaxial quarter wave resonator. This paper deals with the actual development status of this RF system, including analytically derived voltage demands, multipactor thresholds and considerations on input coupling and HOM damping.

MOPP095	Advanced Experimental Techniques for RF and DC Breakdown Research	plasma, vacuum, simulation, ion	775
	J. W. Kovermann RWTH, Aachen S. Calatroni, A. Descoeudres, T. Lefevre, W. Wuensch CERN, Geneva
	Advanced experimental techniques are being developed to do in-situ analysis of DC and RF breakdowns. First measurements with a specially built spectrometer have been made with a DC spark setup at CERN and with CLIC accelerating structures in the 30GHz power test facility. This spectrometer measures the light intensity development during a breakdown for narrow wavelength intervals in the visible and near infrared range which will give information about the involved elements, temperature and plasma parameters and eventually precursors of a breakdown. Planned experiments for X-ray spectroscopy and imaging, measurements of RF-signals and ion and electron energy distribution and infrared imaging of breakdown sites are presented.

MOPP100	Performance of Compact Electron Injector on Evanescent Oscillations	gun, coupling, cathode, resonance	790
	V. V. Mytrochenko, M. I. Ayzatskiy, I. V. Khodak, K. Kramarenko, V. A. Kushnir, A. Opanasenko, S. A. Perezhogin, D. L. Stepin, Z. V. Zhiglo NSC/KIPT, Kharkov
	An injector on the basis of a resonator structure with exponentially increasing amplitude of the electric field along an axis was developed at NSC KIPT. The injector is supplied with RF power through a rectangular-to-coaxial waveguide transition to provide axial symmetry of the accelerating field. The injector was designed to provide the output current up to 1 A at particle energy up to 1 MeV. Results of the injector test are presented in the work. Results obtained are compared with calculated ones.

MOPP106	Study of Radiation From RF Cavities	photon, radiation, acceleration, background	805
	R. Sandstrom DPNC, Genève D. Huang IIT, Chicago, Illinois J. Norem ANL, Argonne, Illinois
	Essential for muon accelerators such as neutrino factories or muon colliders, ionization cooling channels use RF cavities to restore the energy lost in liquid hydrogen absorbers. One major limitation in cooling comes from electrons emitted from the cavities which can cause breakdowns or unacceptable thermal load to the liquid hydrogen vessels. In the Muon Ionization Cooling Experiment MICE, these electrons also cause background in the detectors. This paper presents simulations related to these dark currents, and analysis of data from a direct measurement of this radiation in the MuCool Test Area (MTA).

MOPP109	Status of the 100 MeV Preinjector for the ALBA Synchrotron	linac, gun, diagnostics, single-bunch	811
	A. Falone, D. Einfeld, M. Pont ALBA, Bellaterra D. Jousse, J.-L. Pastre, F. Rodriguez, A. S. Setty THALES, Colombes A. Sacharidis EuroMev, Buc
	A turn key 100 MeV linac has been constructed by THALES in order to inject electrons into the booster synchrotron of ALBA. The linac will be commissioned in May 2008. This paper will remind the main features of the linac* and will give results obtained during the commissioning tests. The energy and emittance measurements will be done on the transfer line conceived and realized by CELLS. * D. Einfeld "Status of ALBA", PAC07, Albuquerque, USA, June 2007. ** A. Setty "Beam dynamics of the 100 MeV preinjector for the spanish synchrotron ALBA", PAC07, Albuquerque, USA, June 2007.

MOPP126	Experimental Characterization of a 700 MHz β=0.47 5 Cell Superconducting Cavity Prototype for Pulsed Proton Linac	proton, linac, simulation, acceleration	853
	G. Devanz, J.-P. Charrier, S. Chel, Y. Gasser, P. Hardy, J. Plouin, J. P. Poupeau, D. Roudier CEA, Gif-sur-Yvette
	A 700 MHz 5 cell elliptical cavity has been developed to accelerate a high intensity proton beam in the lower energy part of a superconducting linac, starting at 80 MeV. The cavity is stiffened in order to minimize the Lorentz detuning which limits high field pulsed operation of the flatter, low beta elliptical cavities. It is equipped with a stainless steel helium vessel. The RF tests of the cavity have been carried out at 1.8 K. Cavity performance is reported in this paper. Measurements of the RF response to mechanical excitations are also presented.

MOPP130	SRF Technology-Past, Present and Future Options	superconductivity, vacuum, controls, radio-frequency	865
	G. Myneni, M. Hutton Jefferson Lab, Newport News, Virginia
	Superconducting radiofrequency cavities for all recent projects (CEBAF, SNS, KEKB, and TTF) have been built from high purity polycrystalline niobium with a residual resistance ratio (RRR) greater than 250. The procedures and processes used from the initial production of the high RRR polycrystalline niobium sheets to the finished cavities are complex, numerous and very expensive, and the yield of SRF cavities meeting the performance specifications is very low. CBMM – Jefferson Lab invented the large grain and single crystal niobium technologies, and the use of niobium sliced directly from the ingots is expected to change the SRF technology outlook with fewer, and more streamlined, production processes that will not only be cost effective but also generate high yield. In this paper we will show that less stringent commercial niobium specifications are required, and explore the processes and procedures that will lay the foundation for producing SRF cavities with good quality factors at high peak magnetic fields in order to make this technology friendlier for future scientific and technological applications.

MOPP131	Cryomodule Tests of the STF Baseline 9-cell Cavities at KEK	radiation, superconducting-RF, linac, coupling	868
	E. Kako, H. Hayano, S. Noguchi, N. Ohuchi, M. Sato, T. Shishido, K. Watanabe, Y. Yamamoto KEK, Ibaraki
	The STF-Baseline superconducting cavity system, which includes four TESLA-type 9-cell cavities, input couplers and frequency tuners, has been developed for the future ILC project. A 6m-cryomodule including one of four STF-Baseline cavities was assembled for the initial test called the STF Phase -0.5. The first cool-down of the cryomodule and high power tests of the STF-Baseline cavity had been successfully carried at 2 K. The maximum accelerating gradient (Eacc,max) of 19.3 MV/m was achieved in a specific pulse width of 1.5 msec and a repetition of 5 Hz, (23.4 MV/m in a shorter pulse of 0.6 msec). The onset of x-rays radiation was observed at higher field than 15 MV/m, and the measured Qo value was about 5 x 10⁹ at 18 MV/m in accompanied with field emission. The detuning angle of about -13 degrees at 18 MV/m was successfully compensated to nearly zero by a combined operation with both an offset detuning and an optimised applied voltage in the piezo element. String assembly of four STF-Baseline cavities has been stated in Jan. 2008. The second cryomodule test for 4 cavities, called the STF Phase -1.0, is scheduled in this early summer.

MOPP135	Vertical and Horizontal Test Results of 3.9 GHz Accelerating Cavities at FNAL	resonance, pick-up, instrumentation, alignment	874
	T. N. Khabiboulline, H. T. Edwards, M. H. Foley, E. R. Harms, A. Hocker, D. V. Mitchell, A. M. Rowe, N. Solyak Fermilab, Batavia, Illinois
	The 3rd harmonic 3.9GHz accelerating cavity was proposed to improve the beam performance of the electron/positron linear accelerators. In the frame of a collaborative agreement, Fermilab will provide DESY with a cryomodule containing a string of four cavities. Several 9-cell Nb cavities were tested and they did reach accelerating gradient up to 24 MV/m almost twice more than design value of 14 MV/m. Two of these cavities are with new HOM couplers with improved design. In this paper we present all results of the vertical and horizontal tests.

MOPP136	Performance of Single Crystal Niobium Cavities	resonance, cryogenics	877
	P. Kneisel, G. Ciovati Jefferson Lab, Newport News, Virginia A. Brinkmann, D. Reschke, W. Singer, X. Singer DESY, Hamburg
	We have fabricated and tested a total of six single cell niobium cavities, made from single crystal, high purity niobium. Two of the three cavities of the TESLA shape (1300 MHz) were made from Heraeus niobium by extending a smaller single crystals by rolling and annealing steps; the third cavity was made by spinning. The three other cavities of the scaled LL shape (2) and TESLA shape (1) resonated at 2.3 GHz and were fabricated from “as received” single crystals, both from Heraeus and CBMM niobium. After appropriate surface treatments by buffered chemical polishing and electropolishing all cavities performed quite nicely and peak surface magnetic fields of ~ 160 mT or above corresponding to accelerating gradients between 38 MV/m and 45 MV/m were reached. This paper reports about the performance of these cavities.

MOPP137	MultiPac 2.1 - Multipacting Simulation Package with a 2D FEM Field Solver for a Microsoft Windows System	simulation, RF-structure, superconductivity, vacuum	880
	Y. M. Li, S. An, Y.-S. Cho, L. Zhang KAERI, Daejon P. Ylä-Oijala Helsinki University of Technology, Helsinki
	MultiPac 2.1 is a multipacting simulation package for analyzing electron multipacting in axisymmetric RF structures with TM_0nl mode, such as RF cavities, coaxial input couplers and ceramic windows. The original package was written by P. Ylä-Oijala, and works with MATLAB 5.0 or 6.0 on Linux operating system. In order to use this code easily for Microsoft Windows customers, we have transferred the MultiPac 2.1 from the Linux system to the Microsoft Windows system. The revised MultiPac can work with Microsoft Windows MatLab 6.0 or later editions smoothly. In this paper, the installation and operation of the Windows MutiPac 2.1 have been introduced. This work was supported by the 21C Frontier R&D program in Ministry of Science and Technology of the Korean Government.

MOPP153	Cavity Diagnostics Using Rotating Mapping System for L-band ERL Superconducting Cavity	radiation, diagnostics, linac, quadrupole	907
	H. Sakai, K. Shinoe ISSP/SRL, Chiba T. Furuya, T. Takahashi, K. Umemori KEK, Ibaraki M. Sawamura JAEA/ERL, Ibaraki
	We are developing the L-band superconducting cavity for Energy Recovery Linac in Japan. In order to survey the electron emission and the heating spot of the cavity inner surface in detail, cavity diagnostics with the rotating mapping system was applied for the vertical tests of our cavities. Two types of sensor, one of which is the carbon resistor and the other is the Si PIN photo diode, was equipped to detect the temperature rise and electron emission. These two sensor arrays were arranged along the cavity axis and set on the rotating mechanics with servo motor. By rotating the sensor arrays around the cavity axis, a lot of information is obtained all over the cavity surface in detail. It is preferable that the number of sensors will be reduced compared with the usual cavity mapping system by using this rotating mapping system. We have already fabricated the Nb single cell cavities which is optimised for ERL operation and then performed the vertical test of Nb ERL single cell cavities. This paper reports the results of the mapping system with Nb single cell ERL-shape cavities.

MOPP158	Conceptual Design of Automated Systems for SRF Cavity Optical Inspection and Assembly	radio-frequency, linear-collider, collider	922
	T. Tajima, A. Canabal, T. A. Harden, R. J. Roybal LANL, Los Alamos, New Mexico
	The International Linear Collider (ILC) will require ~16,000 Superconducting Radio-Frequency (SRF) cavities at an accelerating gradient of 31.5 MV/m. One of the critical issues that needs to be addressed is the insufficient yield of high-gradient cavities that meet the requirement. This paper describes the design and initial tests of a cavity inner surface optical inspection system. Combined with a full-featured 9-cell cavity temperature mapping system being developed at LANL, we hope to be able to correlate the cavity heating and the surface condition causing it.

MOPP161	Plasma Etching Rates and Surface Composition of Bulk Nb Treated in Ar/Cl2 Microwave Discharge	plasma, survey, ion, monitoring	928
	M. Raskovic, S. Popovic, J. Upadhyay, L. Vuskovic ODU, Norfolk, Virginia H. L. Phillips, A-M. Valente-Feliciano Jefferson Lab, Newport News, Virginia
	To achieve theoretically predicted values of the accelerating fields in superconducting radiofrequency (SRF) cavities, their inside surface should be fairly smooth and free of impurities. Thus, surface preparation is the critical step in production of SRF cavities. Plasma etching process is a dry chemistry technique that can be used to achieve these requirements. It is based on interaction between reactive halogen species produced in the glow discharge and the surface. During this process, volatile Nb halides are evaporated from the surface of Nb, removing the mechanically damaged and contaminated layer. We present treatment of bulk Nb samples in the Ar/Cl2 microwave discharge. We achieved etching rates comparable to the rates obtained with the electropolishing method without introducing impurities in Nb. The rate dependence on various discharge parameters and reactive gas composition is presented. Surface composition and topology measurements were carried out before and after plasma treatment to determine level of impurities. Optimal experimental conditions determined on samples will applied be on single cell cavities, pursuing improvement of their RF performance.

MOPP162	Titanium Nitride Coating of RF Ceramic Windows by Reactive DC Magnetron Sputtering	vacuum, lattice, target, controls	931
	V. Variola, H. Jenhani, W. Kaabi, P. Lepercq LAL, Orsay G. Keppel, V. Palmieri, F. Strada INFN/LNL, Legnaro, Padova
	Alumina is a common material for RF windows. Besides its high dielectric strength, it is stable under thermal treatment and has a low out-gassing rate. Nevertheless it has a high secondary electron emission (SEE) coefficient, which leads to multipactor limiting the achievable RF power. One way to suppress the multipactor on RF windows is to coat it with a low SEE-thin TiN film. In the frame of the LAL coupler program a sputtering bench has been developed. It is equipped with two magnetrons and titanium targets. A special rotating holder was designed to allow uniform deposition on cylindrical windows. RF etching of the substrate as a pre-treatment step is allowed, in order to remove particle contamination and to increase TiN adhesion. The TiN sputtering needs the optimisation of gas and electrical parameters. XRD analysis was performed to check the film composition and stoechiometry. The results show how to control the N2 vacancy acting on the gas flow. In addiction, the coating thickness must be optimized not to cause excessive ohmic heating, so multipactor thresholds measurements were done for different coating thickness. Thickness measurments showed a good uniformity.

TUXG02	High Luminosity Operation, Beam-Beam Effects and Their Compensation in TEVATRON	proton, antiproton, luminosity, collider	951
	V. D. Shiltsev Fermilab, Batavia, Illinois
	During the recent years a remarkable increase of the TEVATRON luminosity was achieved. The presentation discusses the collider performance, how this was achieved and illustrates today's limitations. The TEVATRON will shutdown soon but many ideas that emerged from the TEVATRON are of great interest for future (hadron) colliders. As an example, the experience gained at the TEVATRON in understanding of beam-beam effects in hadron colliders and their compensation is highly relevant for future projects. Experimental results of the Tevatron Electron Lenses will be presented and possible use of similar lenses in LHC and RHIC will be discussed.
	Slides

TUOAG01	VEPP-2000 Electron-Positron Collider Commissioning and First Results of Round Colliding Beam Tests	injection, vacuum, lattice, radiation	956
	Y. M. Shatunov, D. E. Berkaev, I. Koop, A. P. Lysenko, E. Perevedentsev, A. L. Romanov, P. Yu. Shatunov, D. B. Shwartz, A. N. Skrinsky BINP SB RAS, Novosibirsk
	VEPP-2000 electron-positron collider construction has been completed in the Budker INP at the beginning of 2007 year. First beam was captured in a special lattice without final focus solenoids. In this regime all systems of power supplies, machine control and beam diagnostics were calibrated and tuned. In the same mode vacuum chamber treatment by synchrotron radiation was performed with electron beam current up to 150 mA. The first test of the round beam option was performed at the energy of 508 MeV with the solenoidal field 10 T in two interaction straight sections. Studies of the beam-beam interaction have been done in "weak-strong" and "strong-strong" regimes. Measurements of beam sizes in the both cases have indicated a beam behavior similar to expectations for the round colliding beams.
	Slides

TUOAG02	Commissioning of BEPCII	luminosity, injection, vacuum, optics	959
	J. Q. Wang, L. Ma, C. Zhang IHEP Beijing, Beijing
	BEPCII is the upgrade project of Beijing Electron Positron Collider (BEPC), serving continuously for both high energy physics experiment and light soure use. As an e⁺-e^- collider, BEPCII will operate in the beam energy region of 1-2.1 GeV with design luminosity of 1*10³³cm^-2s^-1 at 1.89 GeV. The beam commissioning of BEPCII storage rings started out in Nov. 2006. From Nov. 2006 to Aug. 2007, the phase one commissioning was carried out successfully with the so called backup scheme adopting conventional magnets in the IR intead of the superconducting insertion magnets (SIM). After the SIM was intalled into the interaction region, phase two commissioning began in Oct. 2007. The tuning method for high luminosity but low background was extensively studied during phase two, and the beam current has reached more than 1/3 of the design of 0.91 A. The third phase of beam commissioning is planned in May this year after the detector is moved into the on-line position. It is expected that the luminosity would reach to about 30% of its design specification. This paper describes the procedure of beam commissioning of BEPCII and focuses on results of its second phase.
	Slides

TUOBG01	Observations of Beam-beam Tune Spectrum and Measurement of Coherent Tune Shift at KEKB	luminosity, emittance, positron, betatron	962
	T. Ieiri, Y. Ohnishi, M. Tobiyama, S. Uehara KEK, Ibaraki
	KEKB is a double-ring electron/positron collider with a horizontal crossing angle. The crab cavities installed in 2007 achieved an effective head-on collision and gained a higher specific luminosity. Under the new crabbing collision as well as the horizontal crossing collision, tune spectra of a colliding bunch were observed on a spectrum analyzer to study beam-beam effects. The beam-beam spectrum showed strong nonlinear resonant phenomena. Considering the nonlinearity, the coherent beam-beam tune shift was measured as a function of the bunch current. It was confirmed that the vertical beam-beam parameter estimated from the coherent beam-beam tune shift agreed with a value obtained from a bunch-by-bunch luminosity monitor. The estimated vertical beam-beam parameter was saturated on a level of about 0.04, which is called a beam-beam limit. We found that the bunch current corresponding to the beam-beam limit was far below the bunch current used in the usual operation.
	Slides

TUOBG03	Electron Beam Dynamics in the Long-pulse, High-current DARHT-II Linear Induction Accelerator	induction, impedance, focusing, dipole	968
	C. Ekdahl, E. O. Abeyta, P. Aragon, R. D. Archuleta, G. V. Cook, D. Dalmas, K. Esquibel, R. J. Gallegos, R. W. Garnett, J. F. Harrison, E. B. Jacquez, J. Johnson, B. T. McCuistian, N. Montoya, S. Nath, K. Nielsen, D. Oro, L. J. Rowton, M. Sanchez, R. D. Scarpetti, M. Schauer, G. J. Seitz, H. V. Smith, R. Temple LANL, Los Alamos, New Mexico H. Bender, W. Broste, C. Carlson, D. Frayer, D. Johnson, C.-Y. Tom, C. P. Trainham, J. T. Williams NSTec, Los Alamos, New Mexico T. C. Genoni, T. P. Hughes, C. H. Thoma Voss Scientific, Albuquerque, New Mexico B. A. Prichard, M. E. Schulze SAIC, Los Alamos, New Mexico
	We are now operating the full-scale DARHT-II linear induction accelerator (LIA) at its rated energy, accelerating 2-kA electron beams to more than 17 MeV. The injector produces a beam pulse with a full-width at half maximum (FWHM) greater than 2.5 microseconds, and a ~0.5 microsecond rise time. This long risetime is deliberately scraped off in a special beam-head cleanup zone (BCUZ) before entering the 68-cell main accelerator. The accelerated electron beam pulse has a flat-top region where the final electron kinetic energy varies by less than 1% for more than 1.5 microseconds. We will discuss the tuning of the injector, BCUZ, and accelerator; and we will present data for the resulting beam transport and dynamics. We will also present beam stability data, which we will relate to previous stability experiments at lower current and energy. Carl Ekdahl et al. "Long-pulse beam stability experiments on the DARHT-II linear induction accelerator," IEEE Trans. Plasma. Sci. Vol. 34, 2006, pp. 460-466.
	Slides

TUOBG04	A Vlasov-Maxwell Solver to Study Microbunching Instability in the FERMI@ELETTRA First Bunch Compressor System	dipole, quadrupole, synchrotron, emittance	971
	G. Bassi Liverpool University, Science Faculty, Liverpool G. Bassi Cockcroft Institute, Warrington, Cheshire J. A. Ellison, K. A. Heinemann UNM, Albuquerque, New Mexico
	Microbunching can cause an instability which degrades beam quality. This is a major concern for free electron lasers where very bright electron beams are required. A basic theoretical framework for understanding this instability is the 3D Vlasov-Maxwell system. However, the numerical integration of this system is computationally too intensive at the moment. As a result, investigations to date have been done using very simplified analytical models or numerical solvers based on simple 1D models. We have developed an accurate and reliable 2D Vlasov-Maxwell solver which we believe improves existing codes. Our solver has been successfully tested against the Zeuthen benchmark bunch compressors. In the present contribution we apply our self-consistent, parallel solver to study the microbunching instability in the first bunch compressor system of FERMI@ELETTRA. This system was proposed as a benchmark for testing codes at the September'07 workshop on microbunching instability in Trieste. PAC2007, papers TUZBC03 and THPAN084. **https://www.elettra.trieste.it/FERMI/index.php?n=Main. MicrobProgram
	Slides

TUOCG03	Proposal for a ½ MW Electron Linac for Rare Isotope and Materials Science	proton, target, linac, site	985
	S. R. Koscielniak, P. G. Bricault, B. Davids, J. Dilling, M. Dombsky TRIUMF, Vancouver D. Karlen Victoria University, Victoria, B. C.
	TRIUMF, in collaboration with university partners, proposes to construct a megawatt-class electron linear accelerator (e-linac) as a driver for U(gamma,f) of actinide targets with rates up to 10¹³ - 10¹⁴ fissions/sec and for (gamma,p)8Li for materials science. The particular emphasis would be on neutron-rich species. The 50 MeV, 10 mA, c.w. linac is based on super-conducting radio-frequency (SRF) technology at 1.3 GHz. Though high power/current electron linacs are a mature technology proposed elsewhere for applications ranging from 4th generation light-sources to TeV-scale linear colliders, TRIUMF is in the vanguard for applying this technology to the copious production of isotopes for studies of (i) nuclear structure and astrophysics; and (ii) beta-NMR for materials science.
	Slides

TUOBM01	Advanced Design of the FAIR Storage Ring Complex	antiproton, ion, storage-ring, injection	1004
	M. Steck, C. Dimopoulou, A. Dolinskii, O. E. Gorda, V. Gostishchev, K. Knie, S. A. Litvinov, I. Nesmiyan, F. Nolden, D. Obradors-Campos, C. Peschke GSI, Darmstadt
	The storage ring complex of the FAIR comprises three storage rings with a magnetic rigidity of 13 m. Each of the three rings, CR, RESR, and NESR, serves specific tasks in the preparation of secondary beams, rare isotopes and antiprotons, or for experiments with heavy ion beams. The CR is optimized for fast stochastic pre-cooling of secondary beams. The RESR design has been recently revised for optimum performance of antiproton accumulation. The concept for the installation of both rings in a common building is elaborated. The ion optical and engineering design of the NESR for experiments with heavy ions, the deceleration of ions or antiprotons for a subsequent low energy facility, and the accumulation of rare isotope beams is proceeding. A section for collision experiments with circulating ions and counter propagating electrons or antiprotons has been worked out. This report will give a summary of the various new concepts conceived in the process of the design of this new storage ring facility.
	Slides

TUZM01	Recent Development of Diagnostics on 3rd Generation Light Sources	emittance, diagnostics, feedback, injection	1016
	G. Rehm Diamond, Oxfordshire
	A Review of the most performing diagnostics on 3rd generation light sources will be given. Starting with the target performance specification of recent 3rd generation light sources, the demands for diagnostics will be highlighted. Topics include beam position monitors and their integration, emittance measurement by imaging of the stored beam or interference methods and diagnostic requirements for top-up operation. A survey on recent developments and the achieved performances at different accelerators will be presented.
	Slides

TUZM02	Overview of Fast Beam Position Feedback Systems	feedback, controls, collider, synchrotron	1021
	D. Bulfone ELETTRA, Basovizza, Trieste
	Modern circular and linear accelerators often rely on fast beam position feedbacks for the achievement of their design parameters. Such systems have gone through a significant evolution, which has taken advantage of recent progress of the associated equipment, like beam position monitors, as well as of the hardware and software processing technologies. A review of the latest developments and foreseen designs at different accelerators is given.
	Slides

TUPC002	Design of a Tomography Module for the PITZ Facility	quadrupole, diagnostics, emittance, space-charge	1038
	G. Asova, K. Floettmann DESY, Hamburg D. J. Holder, B. D. Muratori STFC/DL/ASTeC, Daresbury, Warrington, Cheshire S. Khodyachykh, S. A. Korepanov, M. Krasilnikov, S. Rimjaem, F. Stephan DESY Zeuthen, Zeuthen
	The goal of the Photo Injector Test Facility at DESY in Zeuthen (PITZ) is to develop sources of high phase-space density electron beams that are required for the successful operation of SASE FELs. This requires detailed characterization of the sources and therefore the development of suitable advanced diagnostics. As part of the ongoing upgrade towards higher beam energies, new diagnostics components are being installed. An example is a tomography module for transverse phase space reconstruction which is designed to operate in the energy range between 15 and 40 MeV. The module consists of four observation screens with three FODO cells between them. A number of upstream quadrupoles are used to match the beam envelope parameters to the optics of the FODO lattice. This contribution presents the final design of the tomography module. Data from numerical simulations are used to illustrate the expected performance and to compare it to a simplified setup of two quadrupoles. The quality of the reconstruction is revised with the help of different algorithms.

TUPC005	Simulation Study of Laser-wires as a Post-linac Diagnostic for CLIC and ILC	background, linac, dipole, simulation	1047
	G. A. Blair, L. Deacon, S. Malton Royal Holloway, University of London, Surrey I. V. Agapov, A. Latina, D. Schulte CERN, Geneva
	Realistic CLIC and ILC bunch trains are simulated in the linac, including intra-train collective effects, and then analysed via a realistic simulation of a laser-wire system, including effects of laser-wire signal extraction, detection and deconvolution. Implications are drawn for the use of laser-wires as a post-linac machine diagnostic.

TUPC011	Micron Size Laser-wire System at the ATF Extraction Line	laser, 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.

TUPC015	Data Acquisition and Analysis in SSRF BPM System	storage-ring, booster, controls, closed-orbit	1077
	Y. B. Yan, Y. Z. Chen, Y. B. Leng, W. M. Zhou, Y. Zou SINAP, Shanghai
	The beam position monitor (BPM) system in Shanghai Synchrotron Radiation Facility (SSRF) is fully (Linac, transfer line, booster and storage ring) equipped with Libera Electron BPM Processors. Primary data acquisition and position calculation has been done in Libera FPGA. EPICS support package developed by Diamond Light Source has been adapted to link BPM system with accelerator control system. Two dedicated soft IOCs are introduced to collect beam position data from all Libera IOCs and calculate RMS noise, histogram, spectrum and phase space, etc. online. Other BPM based analysis is completed via MATLAB scripts. The initial results during booster and storage ring commissioning will be described in this paper.

TUPC018	New Experimental Results with Optical Diffraction Radiation Diagnostics	radiation, background, target, shielding	1083
	E. Chiadroni, M. Castellano INFN/LNF, Frascati (Roma) A. Cianchi INFN-Roma II, Roma K. Honkavaara, G. Kube DESY, Hamburg
	The characterization of the transverse phase space for high charge density and high energy electron beams is demanding for the successful development of the next generation light sources and linear colliders. The interest in a non-invasive and non-intercepting beam diagnostics is increasingly high due to the stringent features of such beams. Optical Diffraction Radiation (ODR) is considered as one of the most promising candidates to measure the transverse beam size and angular divergence, i.e. the transverse emittance. An experiment, based on the detection of the ODR angular distribution, has been set up at DESY FLASH Facility to measure the electron beam transverse parameters. In this paper we report the recent results on the incoherent diffraction radiation produced by a 1 GeV energy electron beam going through a rectangular slit.

TUPC019	A Retarding Field Detector to Measure the Actual Energy of Electrons Participating in E-cloud Formation in Accelerators	controls, simulation, power-supply, pick-up	1086
	R. Cimino, M. Commisso, T. Demma, S. Guiducci, P. Liu, A. R. Raco, V. Tullio, G. Viviani INFN/LNF, Frascati (Roma) P. Vilmercati ELETTRA, Basovizza, Trieste
	Electron cloud related phenomena can cause potentially detrimental effects on beam stability in many planned and under construction accelerators. The possibility to reduce such unwanted phenomena lies on the observation that, machine commissioning does reduce Secondary Electron Yield (SEY). Such SEY reduction (scrubbing) is due to the fact that electrons produced during e-cloud formation hit the accelerator wall, modifying their surface properties. ‘Scrubbing” has been studied only as a function of impinging electron dose but never as a function of the e-cloud electron energy. Simulations predict that the e-cloud is formed by electrons with very low energies (<50 eV). Given the potentially lower scrubbing efficiency for equal dose of very low energy electrons compared to medium energy one, it would be important to measure the actual energy of the electrons forming the cloud in real accelerators. For this reason we decided to construct an optimized retarding Field energy electrometer to be installed in accelerators. Here we will describe what solutions have been adopted during the design phase of such “home made” detector and some laboratory test will be showed and discussed.

TUPC026	Simulating a UMER Beam Position Monitor	simulation, coupling, dipole, quadrupole	1104
	K. Fiuza IF-UFRGS, Porto Alegre S. Bernal, I. Haber, R. A. Kishek UMD, College Park, Maryland
	We have investigated numerically and experimentally a beam position monitor (BPM), using the WARP code* to study image charge effects for an off-axis beam. In order to apply the theory of image charge, we calibrated the BPM response for the University of Maryland Electron Ring*. We studied the BPM linearity using several WARP simulations with different transverse offsets. The simulations were also compared with offsets measured employing a phosphor screen. In this paper we report the methodology used and results of this work. D. P. Grote et. all "New Developments in WARP Progress Toward End-to-End Simulation", Fus. Eng. & Des. 32-33 (1996) 193. ** J. Harris et. all "A fast beam position monitor for UMER", PAC'01, p 1387.

TUPC028	Design and Construction of an Inductive Pick-up for Beam Position Monitoring in the TBL Line of the CTF3	pick-up, vacuum, linac, monitoring	1110
	J. J. Garcia-Garrigos, J. V. Civera-Navarrete, A. Faus-Golfe IFIC (CSIC-UV), Valencia
	In order to determine the beam position respect to the vacuum chamber, the IPU senses the azimuthal distribution of the beam image current flowing along its inner wall when a high frequency bunched beam passes through. The inner wall of the pick-up is divided into four electrodes, each of which forms the primary winding of a toroidal transformer. Therefore the beam image current component flowing through each electrode is transformed to a secondary winding connected to a pick-up output. The closer the beam is to the transformer electrode, the greater is the induced signal in its secondary winding. This basic sensing mechanism will allow to determine the beam position through the four transformers distributed orthogonally around the vacuum pipe. The bandwidth of the IPU and the amplifier is set above 200 MHz to let pass, with low distortion, the 20-140 ns pulse train signal induced from the beam. Also, its expected resolution at maximum current is 5μm. This paper reports on the design, construction as well as testing and calibration processes of two IPU prototypes. They will be installed in the Test Beam Line (TBL) of the 3rd CLIC Test Facility (CTF3) at CERN by Spring 2008.

TUPC030	Transverse Electron Beam Size Effect on the Bunch Profile Determination with Coherent Radiation Diagnostics	optics, radiation, diagnostics, free-electron-laser	1113
	O. Grimm, H. Delsim-Hashemi, J. Rossbach Uni HH, Hamburg V. Balandin, N. Golubeva DESY, Hamburg
	Longitudinal diagnostics of electron bunches can be done by measurement of coherent radiation (e.g., in the form of transition radiation) and subsequent extraction of the form factor. By measuring short wavelengths, fine structures in the bunch can be resolved. However, the form factor depends on the three-dimensional charge density distribution, and the usual practice of considering only a one-dimensional line charge in interpreting the radiation spectra is questionable, as the finite transverse extend of the electron bunch can reduce the form factor magnitude at short wavelengths. An experimental study of this issue using a two stage single shot spectrometer has been carried out at the FLASH free-electron laser at DESY, Hamburg. The coherent transition radiation spectra for two beam optics settings were recorded and compared. In one setting the transverse beam size at the transition radiation target screen has been blown up by a factor of about 3.5 compared to the second setting. The ratio of these two spectra shows a suppression of radiation intensity at short wavelengths, as expected from a theoretical calculation. In this paper the result of this study is presented.

TUPC031	Longitudinal Beam Diagnostics Application of Synchrotron Radiation at FLASH	radiation, synchrotron, synchrotron-radiation, monitoring	1116
	O. Grimm, J. Rossbach Uni HH, Hamburg C. Behrens, B. Schmidt DESY, Hamburg
	For the operation of the FLASH free electron laser at DESY, Hamburg, tools to measure the longitudinal charge distribution and especially its stability over time are important for efficient machine running. Several techniques using both coherent far-infrared and incoherent visible synchrotron radiation from the two bunch compressor chicanes are summarized and compared in this paper. The experimental setups used are a Martin-Puplett interferometer with both a room-temperature pyroelectric and a liquid-Helium cooled bolometer as detector, a streak camera to directly measure the time profile, the analysis of intensity fluctuations of the optical synchrotron radiation measured (with a photomultiplier) through a narrow filter, a single shot grating spectrometer covering the spectral range from 5 μm to 150 μm. Data from the various and complementary experimental methods will be presented and compared.

TUPC032	Phase Space Tomography Using the Cornell ERL DC Gun	emittance, quadrupole, gun, diagnostics	1119
	F. E. Hannon Jefferson Lab, Newport News, Virginia I. V. Bazarov, B. M. Dunham, Y. Li, X. G. Liu Cornell University, Department of Physics, Ithaca, New York
	The brightness and quality of electron beams in linac-based light sources are ultimately limited by the properties of the beam in the injector. It is thus important to have knowledge of the phase space distribution in addition to the rms emittance to provide an insight into high beam brightness formation mechanisms. A tomography technique has been used to reconstruct the transverse phase space of the electron beam delivered from the Cornell University ERL DC gun. The tomography diagnostic utilised three solenoid magnets directly after the DC gun and a view-screen. The injector was operated at 250keV in the emittance dominated regime, and the results showed good agreement to the phase space measured using a slit-screen method and that generated from simulation with the particle tracking code ASTRA. Comparison of various reconstruction methods is provided.

TUPC036	Multi-wire Profile Monitor for J-PARC 3GeV RCS	injection, linac, radiation, superconductivity	1131
	S. Hiroki, N. Hayashi, M. Kawase, F. Noda, P. K. Saha, H. Sako, H. Takahashi, A. Ueno JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken Y. Arakida, S. Lee, T. Toyama KEK, Ibaraki
	A set of six multi-wire profile monitors (MWPMs) has been installed in the injection line and the successive H0 dump line of the RCS (Rapid-Cycling Synchrotron), and contributed to the initial RCS commissioning for establishing an optimum injection orbit. The Au coated W wires (0.1 mm dia.) for the H^- beam detection are fixed to a ceramic wind frame for two directions (horizontal and vertical with 17.7 ^o tilt, typically 51 wires with 2.9 mm or 9.5 mm distance), and the frame can be scanned for horizontal or vertical direction by using a stepping-motor driven actuator. A combination of the 17.7 ^o tilt wires and the precise scan function provides two step measurements, i.e. a rough profile is obtained only at one shot, and a detailed profile is measured for typically 101 shots (10 mm scan at 0.1 mm interval) thereafter. The beam induced charge signals are amplified by the instrumentation pre-amps located in a basement sub-tunnel at distances of 30-40 m from the frame through the shielded twisted pair cables. The signals are further transferred to the sample, hold and multiplex circuits at the ground floor. The digitized profile data are processed to the Gaussian fitting.

TUPC040	Measurements of Beam-beam Kick using a Gated Beam-position Monitor under Crabbing Collision at KEKB	positron, betatron, beam-beam-effects, luminosity	1143
	T. Ieiri, H. Fukuma, Y. Funakoshi, M. Masuzawa, K. Ohmi, M. Tobiyama KEK, Ibaraki
	KEKB is a double-ring electron/positron collider with a horizontal crossing-angle. The crab cavities installed in 2007 achieved an effective head-on collision and gained a higher specific luminosity. A gated beam-position monitor is a tool to measure the beam-beam effects. A beam-beam kick curve was measured by comparing the beam position between colliding and non-colliding bunches, while shifting the beam orbit at the interaction point (IP). An effective horizontal beam size at the IP was obtained from a linear part of the beam-beam kick around the central orbit. The estimated beam size agreed with a calculated value including the dynamic effects. It was confirmed that the effective horizontal beam size was reduced by the crabbing collision, as expected from a calculation with a rigid Gaussian model. When a horizontal orbit offset was larger than a beam size, however, we found that the measured beam-beam kick curve deviated from calculated values using the Gaussian model. The result suggests that the beam profile might enlarge horizontally in the peripheral part.

TUPC045	Setup and Commissioning of the Diagnostics Beamline for the SRF Photoinjector Project at Rossendorf	laser, 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.

TUPC046	Study on Longitudinal Phase-space of High-brightness Electron Beams at ISIR, Osaka University	vacuum, photon, linac, radiation	1161
	R. Kato, T. Igo, G. Isoyama, S. Kashiwagi, M. Morio ISIR, Osaka
	The performance of the free-electron laser based on self-amplified spontaneous emission strongly depends on characteristics of the electron beam, such as its transverse, longitudinal, and energy profiles as well as bunch charge. The longitudinal phase-space for the electron beam consists of the longitudinal position and energy of electrons, and several methods are extensively under study to evaluate the phase-space profile of the electron beam. We are developing a measurement system consisting of a profile monitor, a bending magnet and a streak camera. We first considered an optical transition radiation monitor as the profile monitor, but we could not get the efficient number of photons to obtain the phase-space images since the angular distribution of the transition radiation is too large to concentrate in the electron energy region of 10 – 20 MeV. In order to increase the number of photons, we have changed to a Cherenkov radiator using a hydrophobic silica aerogel. The Cherenkov radiator was installed in the beam transport line from the linac to the FEL system. We will present an outline of the phase-space measurement system and preliminary experimental results.

TUPC047	Optical Transition Radiation Interferometry for the A0 Photoinjector	scattering, vacuum, radiation, optics	1164
	G. M. Kazakevich BINP SB RAS, Novosibirsk H. T. Edwards, R. P. Fliller, S. Nagaitsev, J. Ruan, R. Thurman-Keup Fermilab, Batavia, Illinois
	OTR interferometry (OTRI) is a promising diagnostic technique and was successfully developed and used for investigation of relativistic beams. For mid-energy accelerators the technique is traditionally based on thin polymer films (the first one is transparent for visible light) providing the beam multiple scattering of about 1 mrad or less. The disadvantage of these films is the unacceptable vacuum properties for photoinjectors and accelerators using superconducting cavities. We studied the application of thin mica sheets for OTRI diagnostics at the A0 Photoinjector in comparison with 2.5 μm thick Mylar films. This diagnostic is also applicable for the ILCTA-NML accelerator test facility that is planned at Fermilab. The experimental setups of the OTR interferometer for the A0 Photoinjector are described in the report. Results of simulations and measurements and comparison of the results obtained using Mylar and Mica-based interferometers are presented and discussed.

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

TUPC055	Operating MCP Detectors at Cryogenic Temperatures	cryogenics, vacuum, storage-ring, ion	1179
	K.-U. Kuehnel, C. D. Schroeter, J. Ullrich MPI-K, Heidelberg
	At present, a low energy electrostatic storage ring operating at cryogenic temperatures down to 2 K is being build up at the MPI-K in Heidelberg. Both, beam diagnostics and experiments rely on the use of position sensitive micro-channel plate (MCP) detectors equipped with phosphor screens or delay line anodes. Since little is known about the performance of these detector types in a cryogenic environment a test chamber was built to investigate their properties. A delay line MCP detector was successfully tested at temperatures as low as 25 K. In this contribution the detailed results of theses tests as well as possible applications of the detector are presented.

TUPC058	Laser-based Ion Beam Diagnostics for the Front End Test Stand at RAL	laser, 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)	laser, ion, 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.

TUPC066	Temporal Spot Size Evolution of the DARHT First Axis Radiographic Source	ion, target, focusing, radiation	1206
	B. T. McCuistian, D. C. Moir, E. A. Rose LANL, Los Alamos, New Mexico H. Bender, C. Carlson, C. G. Hollabaugh, R. Trainham NSTec, Los Alamos, New Mexico
	DARHT is the Dual Axis Radiographic Hydrodynamic Test Facility at Los Alamos National Laboratory. The radiographic spot size is a critical parameter in the performance of the facility to produce quality radiographs. Time resolved images of the radiographic spot of the First Axis of the DARHT facility have been acquired and correlated with the radiation pulse. Analysis of these time resolved images illustrates the effect of beam target interaction on the temporal evolution of the spot size. An explanation of the experimental setup and analysis of the data will be presented.

TUPC067	Development of the Methods of Beam Energy Spread Determination in the VEPP-4M Collider	collider, diagnostics, photon, simulation	1209
	O. I. Meshkov, V. A. Kiselev, N. Yu. Muchnoi, S. V. Sinyatkin, V. V. Smaluk, V. N. Zhilich, A. N. Zhuravlev BINP SB RAS, Novosibirsk
	The nearest experimental program of the VEPP-4M electron-positron collider and the KEDR detector includes a scan of the energy area below J/psi meson to search narrow resonances. The monitoring of beam energy spread is important for that. In this report we discuss the application of several diagnostics for beam energy spread measurement. The data obtained with Compton Back-Scattering (CBS) technique are compared with the value of the spread derived from the betatron motion of the beam. Similar experiments were carried out before. They demonstrated the necessity to improve the algorithm of beam energy spread derivation using CBS technique. New set of experiments was aimed on the examination of the improved algorithm. The measurements by all the methods were done at the same accelerator run, i.e., the different diagnostics are compared directly. The value of the energy spread was determined for a fixed collider energy E= 1855 MeV. The beam energy spread was changed by the wiggler current variation.

TUPC071	Computer-assisted Electron Beam Centroid Characterization at AIRIX Facility	diagnostics, beam-transport, extraction, target	1212
	O. Mouton, M. Caron, D. Collignon, H. Dzitko, B. Gouin, G. Grandpierre, D. Guilhem, L. Hourdin, C. Noel, O. Pierret CEA, Bruyères-le-Châtel
	AIRIX is a high current accelerator designed for flash X-ray radiography. The electron beam produced into a vacuum diode (2 kA, 3.5 to 3.8 MV, 60 ns) is extracted from a velvet cold cathode. For a beam characterisation we have seen* how to calculate the mean beam divergence (X'(0),Y'(0)), the RMS beam size (XRMS(0), YRMS(0)) as well as the 2D transverse beam emittance (ex(0),ey(0)). To have a complete initial characterization of the beam, we have to further calculate the centroid initial position (xc, yc) and its initial divergence (xc', yc'). In this aim, we use experimental results at BPM's located downstream the initial position of the cathode, and we also use the TRAJENV code coupled with the MINUIT minimization library. In this paper, we propose to describe both experimental and theoretical approaches leading to the full beam characterization (beam size, centroid position and divergence) at the diode output. *O. Mouton & al. "Computer assisted Electron Beam Characterization at AIRIX Facility," PAC'07, Albuquerque (USA).

TUPC072	Design and Fabrication of an X-band Traveling Wave Deflection Mode Cavity for Longitudinal Characterization of Ultra-short Electron Beam Pulses	diagnostics, dipole, simulation, betatron	1215
	A. Y. Murokh, R. B. Agustsson, S. Boucher, P. Frigola RadiaBeam, Marina del Rey D. Alesini INFN/LNF, Frascati (Roma) R. J. England, J. B. Rosenzweig, G. Travish UCLA, Los Angeles, California V. Yakimenko BNL, Upton, Long Island, New York
	An X-band Traveling wave Deflector mode cavity (XTD) has been developed at Radiabeam Technologies to perform longitudinal characterization of the sub-picosecond ultra-relativistic electron beams. The device is optimized for the 100 MeV electron beam parameters at the Accelerator Test Facility (ATF) at Brookhaven National Laboratory, and is scalable to higher energies. An XTD is designed to operate at 11.424 GHz, and features short filling time, femtosecond resolution, and a small footprint. RF design, fabrication procedure, and commissioning plans are presented. An experimental program at ATF to utilize the deflector for compressed beam characterization is discussed, including proposed measurements of the phase space filamentation due to non-linear processes in a chicane compressor.

TUPC073	A Real-time Bunch Length Terahertz Interferometer	radiation, diagnostics, optics, linac	1218
	G. Andonian, G. Travish UCLA, Los Angeles, California S. Boucher, P. Frigola, A. Y. Murokh RadiaBeam, Marina del Rey
	With the recent development of advanced photoinjectors and next generation light sources, the progression towards high-current, ultra-short beams is very important. The measurement of these short pulses, with sub-picosecond resolution is essential for successful beam operation and optimization. This paper describes the development of a real-time, shot-to-shot bunch length diagnostic utilizing a novel beam auto-correlation technique.

TUPC074	Beam Transverse Size Effects on the Transition Radiation Energy Spectrum	radiation, photon, diagnostics, luminosity	1221
	G. L. Orlandi ENEA C. R. Frascati, Frascati (Roma)
	A theoretical model for the transition radiation emission by a relativistic electron bunch is here presented. Such a model, based on an extension of the virtual quanta method to the case of high density charged beams, predicts the existence of beam transverse size effects on the short wavelength part of the transition radiation energy spectrum. The relevance of such effects to the transition radiation based beam diagnostics of an electron linear accelerator is discussed. The physical consistency of the proposed theoretical model for the transition radiation emission is demonstrated on the basis of the constraints imposed by the temporal causality and Huygens-Fresnel principles. Further arguments in favour of such a thesis, which concern the relativistic nature of the radiative mechanism, are discussed. A possible experiment, devoted to a crosscheck of the theoretical results in an electron linear accelerator, is also proposed.

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

TUPC080	Fermi Low-energy Transverse RF Deflector Cavity	emittance, linac, coupling, RF-structure	1239
	P. Craievich, S. Biedron, C. Bontoiu, S. Di Mitri, M. Ferianis, M. Veronese ELETTRA, Basovizza, Trieste D. Alesini, L. Palumbo INFN/LNF, Frascati (Roma) L. Ficcadenti Rome University La Sapienza, Roma M. Petronio DEEI, Trieste
	The layout of FERMI@Elettra will include a transverse S-band RF deflector that will be located after the first bunch compressor (BC1) at 250 MeV. The deflector will operate in a vertical deflecting mode and coupled to a downstream dipole will be used to measure the electron bunch length and in particular to allow time-resolved beam quality measurements such as horizontal slice emittance and slice energy spread. In this paper we discuss the electron bunch deflection at 250 MeV taking into account the principal elements that dominate the selection of the transverse peak voltage specification: the finite transverse emittance, the resolution of OTR screens and the desired number of the slice divisions along the bunch that we wish to observe. The RF deflector proposed here is a frequency scaled version of the 5-cell standing wave SPARC structure.

TUPC081	Single-shot Longitudinal Bunch Profile Measurements at FLASH Using Electro-optic Detection Techniques	laser, 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.

TUPC089	Robust Emittance Evaluation from Complex Transverse Phase Spaces	emittance, background, damping, booster	1263
	A. R. Rossi, A. Bacci INFN-Milano, Milano
	We present a novel procedure to analyze the transverse phase space of low energy electron bunches, close to a beam waist, in order to retrieve a sound estimate of its emittance. The procedure consist in a genetic code and a non linear fit applied in cascade, the first feeding the parameters starting values of the former. This allows us to cleanse the phase space from noise, separate the core charge from the halos and distinguish between bunch components undergoing different dynamics, such as cross over or the double emittance minima effect. Our procedure performs a rough longitudinal beam tomography, based on dynamical considerations, using transverse data. The application of the procedure to some experimental data is shown.

TUPC090	Ionisation Profile Monitor to Determine Spatial and Angular Stability of FEL Radiation of FLASH	laser, ion, simulation, 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.

TUPC093	Beam Profile Monitor of the J-PARC 3GeV Rapid Cycling Synchrotron	ion, synchrotron, beam-losses, linac	1275
	K. Satou, N. Hayashi, R. Saeki, A. Ueno, K. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken H. Harada Hiroshima University, Graduate School of Science, Higashi-Hiroshima S. Lee, T. Toyama J-PARC, KEK & JAEA, Ibaraki-ken M. Tejima KEK, Ibaraki
	To obtain high intensity (1MW) and large emittance (214 π mm mrad) beam profiles of the 3GeV Rapid Cycling Synchrotron (RCS) of the J-PARC, we have developed the ionization profile monitors (IPMs) with wide active aperture and high dynamic range. It has three Microchannel Plates (MCPs) with active area of 81*41mm for signal multiplication and read out devices, and magnet system to generate guiding fields to collect electrons. The wide active aperture of ±116mm is obtained by arranging the three MCPs perpendicular to the beam axis. Furthermore, the dynamic range of 10⁴ level can be obtained by adjusting each bias voltage of the MCPs. The IPMs are now collecting ions without the guiding fields. The beam commissioning of the RCS has been in progress since last year. The horizontal and vertical profiles are of great help, particularly to check injection errors. At the conference, the present status of the IPM system and the latest beam profiles will be reported.

TUPC094	Longitudinal Bunch Profile Monitoring via Single Shot Diagnostic with Linear Response	laser, 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.

TUPC096	Development of Beam Loss Monitor for the SPring-8 Storage Ring	beam-losses, injection, target, background	1284
	Y. Shimosaki, K. Kobayashi, M. Oishi, M. Shoji, K. Soutome, Y. Taniuchi JASRI/SPring-8, Hyogo-ken
	A beam loss monitor using PIN photodiodes has been developed. To check its performance, we installed it at an in-vacuum insertion device and at the injection section in the SPring-8 storage ring. Information on the beam loss at these points will be useful for examining demagnetization of permanent magnets of insertion devices and for studying a mechanism of beam loss. A noise level at these points is however high due to stray synchrotron radiation, an induction voltage generated by pulsed injection magnets, etc. The beam loss signal is then picked up under a high noise condition. Experimental results with its countermeasure will be reported.

TUPC097	Beam Diagnostics for the Prototype of the Cryogenic Storage Ring CSR	ion, pick-up, diagnostics, vacuum	1287
	T. Sieber, K. Blaum, M. Grieser, M. Lange, F. Laux, T. M. Sorg, A. Wolf, R. von Hahn MPI-K, Heidelberg
	The Cryogenic Storage Ring CSR at the MPI-K Heidelberg will be a 35m circumference, electrostatic ring, which is mainly dedicated to Molecular- and Atomic Physics experiments. To reach the low pressures (10^-15 mbar), which are necessary to achieve the required long liftetimes of the stored ions, the complete ring has to be operated at a temperature below 4K (2K in sections), which means, that it will be installed inside a large cryostat. To prove the novel cryogenics and vacuum concept of the CSR, we have built up a prototype, which is basically a segment of the CSR, housing an electrostatic ion trap. The ion trap is in the first instance used for vacuum measurements and equipment tests in the XHV range, in a later stage, it shall be an experimental facility of its own. Test operation of the Prototype is currently starting. Since the boundary conditions in the CSR are highly demanding for the beam diagnostics system, we have to perform some tests of the CSR diagnostics devices in our Prototype setup. The Poster will describe these devices and present first experimental results.

TUPC099	Wire Scanner for Transverse Beam Parameter Measurements in BEPCII	linac, radiation, vacuum, simulation	1293
	Y. F. Sui, J. Cao, L. Ma IHEP Beijing, Beijing
	The wire scanner has been installed in the linac injector of BEPCII (Beijing Electron-Positron Collider II) to provide the transverse beam parameters. In the several fellowing months, some experiments will be done. The result will be presented and the reason will be analysed.

TUPC102	Cooled Beam Diagnostics on LEIR	ion, diagnostics, pick-up, controls	1296
	G. Tranquille, C. Bal, C. Carli, M. Chanel, V. Prieto, R. S. Sautier, J. Tan CERN, Geneva
	Electron cooling is central in the preparation of dense bunches of lead beams for the LHC. Ion beam pulses from the LINAC3 are transformed into short high-brightness bunches using multi-turn injection, cooling and accumulation in the Low Energy Ion Ring, LEIR. The cooling process must therefore be continuously monitored in order to guarantee that the lead ions have the required characteristics in terms of beam size and momentum spread. In LEIR a number of systems have been developed to perform these measurements. These include Schottky diagnostics, ionisation profile monitors and scrapers. Along with their associated acquisition and analysis software packages these instruments have proved to be invaluable for the optimisation of the electron cooler.

TUPC106	Optimization of Electron Linac Operating Conditions for Photonuclear Isotope Production	target, simulation, radiation, isotope-production	1308
	V. L. Uvarov, A. N. Dovbnya, V. I. Nikiforov, Z. V. Zhiglo NSC/KIPT, Kharkov
	The communication describes the method for optimizing the high-power Linac regime (electron energy, pulsed current and beam size, pulse repetition rate) and the composition of output devices to provide the maximum photonuclear yield of isotope product with the maintenance of thermal stability of structural elements. To exemplify, the results of accelerator KUT-30 (45 MeV, 10 kW) optimization at conditions of medical isotope Cu-67 production are reported. Simulation based on a modified PENELOPE/2006 code was employed to compute the Cu-67 generation rate in the Zn target, and also the absorbed radiation power in output device elements for different operating conditions of the accelerator with due regard for its loading characteristic. The simulation results were used to calculate the target and the converter (Ta) temperature at various thicknesses of the latter and at real cooling parameters. Conditions have been established for the maximum Cu-67 yield with keeping thermal stability of the target device.

TUPC107	Feed-free Monitoring of Intense High-energy Bremsstrahlung	radiation, monitoring, simulation, linac	1311
	V. L. Uvarov, V. I. Nikiforov, V. A. Shevchenko, I. N. Shlyakhov, A. Eh. Tenishev NSC/KIPT, Kharkov
	High-intensity (>10³ W/cm²) bremsstrahlung sources produced on the basis of electron linacs of energy E₀ up to 100 MeV find use in accelerator-driven subcritical assemblies, in photonuclear isotope production, activation analysis, etc. These processes, as a rule, call for maintaining a stable bremsstrahlung flow for one or more days. Therefore the diagnostic means of the radiation must function reliably under conditions of high-absorbed doses (≥10⁸ Gy). To solve the problem, it is proposed to use a direct charge detector (DCD). It consists of two vacuum gap-spaced metal plates of different thickness. The simulation method based on the software PENELOPE/2006 was used to investigate the conditions of equilibrium e, X-radiation formation in the area of detector location, the dependence of detector sensitivity in its standard geometry on the atomic number Z of the plate material and the gammas energy at E₀ ranging from 20 to 100 MeV. The realization of the method has been demonstrated by experiment with the use of the DCD prototype. The proposed detector requires no external power supply, is easy to operate and has a high radiation resistance.

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

TUPC112	Equipment for Electrons Energy Measurement in HLS	storage-ring, beam-losses, polarization, energy-calibration	1326
	H. Xu, G. Feng, B. Sun, L. Wang, J. F. Zhang, X. Zhao USTC/NSRL, Hefei, Anhui
	The parameters necessary to dimension an equipment for the measurement of the beam energy of a storage ring via the resonance depolarisation are collected for HLS . The electron beam polarizes naturally due to the Sokolov-Ternv effect. For Hefei light source(HLS), the polarisation time is approx 4.346 h at 800MeV. The calculated value 4.346h is only for reference. The radial field will be applied to the beam by a pair of striplines mounted in the storage ring vacuum chamber. When input power is 12.5w, with OPRA program, intergrated field is calculated on axial. Different input power V. S integral field is also calculated. Which the depolarization time V. S input power can calculated by the below. The beam loss system for the electron storage ring of HLS can be used to measure the relative change of Touschek lifetime. It is expected that the relative change of Touschek lifetime due to beam depolarization will be measured in the future.

TUPC113	Beam Energy Compensation by RF Amplitude Control for Thermionic RF Gun and Linac Based Mid-infrared FEL	controls, gun, klystron, beam-loading	1329
	H. Zen, T. Kii, R. Kinjo, K. Masuda, H. Ohgaki, S. Sasaki, T. Shiiyama Kyoto IAE, Kyoto
	Institute of Advanced Energy, Kyoto University has constructed a mid-infrared FEL facility which consists of a thermionic RF gun, a traveling-wave type accelerating tube and a halbach type undulator. The electron beam quality is critical for lasing FEL. However, we found that the beam energy after the accelerator tube decreased from 25 to 23.5 MeV (around 6%) during macro-pulse duration (~4μsec), because.the beam current increases from 65 to 120 mA during the macro-pulse due to the backbombardment effect in the RF gun. To compensate the energy drop and to minimize the energy spread over the macro-pulse, the amplitude of RF power fed to the tube was controlled. Since a precise micro-bunch interval required to build up the FEL, the RF phase was also controlled. As the result, the energy spread of the electron beam was greatly reduced from 6 to 0.8% in FWHM which was same with micro-pulse energy spread (~0.8%). The phase stability during macro-pulse was also improved from 10 to less than 2 degree.

TUPC114	Results from the Optical Replica Experiments in FLASH	laser, 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, laser, 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.

TUPC124	Development of a High Power Fibre Laser for Laser Based Electron Beam Diagnostics	laser, collider, linear-collider, 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	laser, 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.

TUPC138	Development of a New Low-Level RF-Control-System for the S-DALINAC	controls, diagnostics, klystron, linac	1389
	A. Araz, U. Bonnes, R. Eichhorn, M. Konrad, M. Platz, A. Richter TU Darmstadt, Darmstadt U. Laier GSI, Darmstadt R. Stassen FZJ, Jülich
	The Superconducting DArmstadt electron LINear ACcelerator S-DALINAC has a maximum energy of 130 MeV and beam currents of up to 60 μA. To reach this energy conveniently in cw, superconducting cavities with a high Q at a frequency of 3 GHz are used. In order to achieve minimal energy spread, the amplitude and phase the cavities have to be controlled strictly in order to compensat the impact of microphonic perturbations. The existing analog rf control system based on a self-exited loop, converts the 3 GHz signals down to the base band. This concept will also be followed by the new digital system currently under design. It is based on an FPGA in the low frequency part, giving a great flexibility in the control algorithm and providing additional diagnostics. For example it is possible to change the operational mode between self-exited loop and generator driven resonator within a second. We will report on the design concept, the status and the latest results measured with a prototype, including different control algorithms as well as beam loading effects.

TUPC142	Performance of 24 Cavity Vector Sum Controller with Distributed Architecture	controls, klystron, laser, 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.

TUPC143	Precise RF Control System of the SCSS Test Accelerator	controls, acceleration, feedback, radiation	1404
	H. Maesaka, T. Fukui, N. Hosoda, T. Inagaki, T. Ohshima, Y. Otake, H. Tanaka RIKEN/SPring-8, Hyogo T. Hasegawa, S. Takahashi, S. Tanaka JASRI/SPring-8, Hyogo-ken M. K. Kitamura NDS, OSAKA
	We present the development and performance of the low level rf control system of SCSS test accelerator (VUV-FEL facility). The FEL radiation in the wavelength region of 50-60 nm reached saturation in fall 2007. Since then, the FEL intensity fluctuation has been suppressed within 10%. This performance was achieved by stabilizing the rf phase and amplitude of the accelerator. For example, the rf phase stability of the 238 MHz cavity is achieved to be 0.03 degree rms corresponding to 350 fs. Those of other cavities such as C-band (5712MHz) accelerator are also obtained to be several 100 fs. To control the rf phase and amplitude precisely, we have developed an IQ modulator / demodulator system. To treat the baseband signal of the system, we have also developed VME high speed DAC / ADC boards. The phase skew of the IQ system is ± 1.0 degree without correction and ± 0.1 degree after correction. To suppress the slow drift of rf components, we applied a PID feedback control loop to the rf source and cavity system. We also improved temperature stabilization for the acceleration structures.

TUPD011	The Pulsed Quadrupole Magnet for KEKB Low Energy Ring	quadrupole, focusing, luminosity, positron	1455
	T. Mimashi, T. Ieiri, M. Kikuchi KEK, Ibaraki A. Tokuchi, K. Tsuchida Nichicon (Kusatsu) Corporation, Shiga
	In the KEKB low energy ring, because of photoelectron clouds, the betatron tune changes along the position in the train. The produced photoelectron gives focusing force to the beam. It is remarkable especially in the vertical tune. Since we have a 500 nanoseconds beam abort gap, the photoelectron focusing force is weaker at the head of train. It means the vertical tune is lower at the head of the train. In order to cancel this tune shift, the pulsed quadrupole magnet was installed. The pulsed quadrupole magnet system and its performance are described.

TUPD022	Electron Beam Polarimetry at the S-DALINAC	scattering, polarization, target, background	1476
	R. Barday, U. Bonnes, C. Eckardt, R. Eichhorn, J. Enders, C. Heßler, J. Kalben, Y. Poltoratska TU Darmstadt, Darmstadt W. F.O. Müller, B. Steiner, T. Weiland TEMF, Darmstadt
	It is planned to carry out experiments at the Superconducting Darmstadt Linear Accelerator S-DALINAC with both polarized electron and photon beams at the energy of the electron beam between 10 and 130 MeV. In order to extract asymmetry from these experiments the absolute degree of the electron beam polarization needs to be known. We present the existing and planned polarimeters at the source of polarized electrons and the experimental sites, especially a 100 keV Mott polarimeter and Möller polarimeter for 15-130 MeV electrons.

TUPD027	Commissioning of the Offline-teststand for the S-DALINAC Polarized Injector SPIN	polarization, cathode, scattering, laser	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.

TUPD028	How to Stably Store Electron Beam in a Synchrotron Radiation Facility from the Point of View of an RF System Design	storage-ring, klystron, synchrotron, synchrotron-radiation	1485
	Y. Kawashima, H. Ego, Y. Ohashi JASRI/SPring-8, Hyogo-ken M. Hara RIKEN Spring-8, Hyogo
	In any synchrotron radiation facilities, the users wish that electron beams are stably stored without beam abortion for as long as possible. It must be recognized that RF system is a main cause of beam abortions. In order to store beam stably, it is necessary for staffs in charge of RF system to foresee various beam instabilities and to take measures. Before discussing coupled-bunch instability problems, one should understand some trivial issues such as ion trapping and fundamental acceleration frequency modulated by high voltage ripple. The former causes transverse mode instability and the latter shakes stored electron beam longitudinally in RF cavities. In newly designed synchrotron radiation facilities, those issues mentioned above should be suppressed before beam commissioning. As for other issues relating with RF system, we would like to state the importance of a water-cooling system with stable temperature for cavities, and the electric earth problem of low level RF system and high voltage power equipment of a klystron. We describe how we have managed those issues in designing of SPring-8 RF system of the storage ring.

TUPD036	G4Beamline Simulations for Detector Development	simulation, radiation, electromagnetic-fields, photon	1506
	T. J. Roberts, K. B. Beard Muons, Inc, Batavia
	In current research programs to develop radiation detection instruments, simplifying assumptions are frequently made in estimating the resolutions and efficiencies attainable by neutron and gamma-ray instruments. Monte Carlo programs (such as Geant4) are capable of realistically modeling such problems, but the technical details of setting up, running, and interpreting the required simulations are beyond the ability of all but the most expert researchers. G4beamline, a program that is an interface to the Geant4 toolkit for the simulation of accelerator beam lines, is being extended to model detectors and related systems needed for applications related to nuclear nonproliferation and other users. The program is flexible, extremely user friendly, and requires no programming by users. Simulations of simple or complex detectors can be setup quickly and are accurately simulated using the power and accuracy of Geant4 for the transport of particles, including scattering, attenuation, interactions, and decays.

TUPD041	The Design of a 5 MeV Accelerator Based on Multipactor Electron Gun	cathode, gun, emittance, coupling	1520
	M. Zhong, C.-X. Tang, S. Zheng TUB, Beijing
	The Multipactor Electron Gun (MPG) based on the multipactor effect can produce short duration, high current and self-bunching electron beams. This paper presents our work on the design of an S-band accelerator based on MPG and the result of preliminary experiment. The mechanical structure was designed with ability of replacing secondary electron emitters. Pd-Ba alloy and Pt were used as the secondary electron emitters of the MPG. The distance between electrodes and the resonant frequency of the MPG can be adjusted separately by step motors. The parameter of the accelerator tube was optimized using numerical simulation with the design outlet energy of the electron is 5MeV and an average current of 100mA.

TUPP001	Alternating Gradient Operation of Accelerating Modules at FLASH	controls, feedback, klystron, laser	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.

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

TUPP018	Impact of Electromagnetic Fields in TESLA RF Modules on Transverse Beam Dynamics	emittance, simulation, undulator, free-electron-laser	1568
	E. Prat, W. Decking, M. Dohlus, T. Limberg, I. Zagorodnov DESY, Hamburg
	Transverse electric fields in TESLA rf modules exist on one hand because of deformations of the longitudinal accelerating field in the presence of rf structure misalignments or in the vicinity of asymmetrically machine parts like input couplers. On the other hand, the beam itself induces transverse wake fields if it does not travel through the center of a perfectly rotationally symmetric structure. Transverse deflecting fields deflect beam particles. The average deflection causes a change in the beam trajectory; the phase dependence of the transverse field leads to a variation of the transverse kick along the longitudinal position of the bunch and thus in general to a change in projected emittance. If the strength of the transverse field component varies along the transverse direction itself, slice emittance will be also affected. We will present the amplitudes and spatial variations of transverse fields generated by the mechanisms described above, and discuss their impact on beam trajectories and shape.

TUPP023	Direct Detection of the Electron Cloud at ANKA	vacuum, simulation, storage-ring, synchrotron	1580
	S. Casalbuoni, A. W. Grau, M. Hagelstein, A.-S. Müller FZK, Karlsruhe U. Iriso ALBA, Bellaterra E. M. Mashkina University of Erlangen-Nürnberg, Physikalisches Institut II, Erlangen R. Weigel Max-Planck Institute for Metal Research, Stuttgart
	Low energy electrons generated by the interaction of high energy particles with the beam pipe surface can be detrimental for accelerators performances increasing the vacuum pressure, the heat load and eventually producing beam instabilities. The low energy electrons accumulating in the beam pipe are often referred to as electron cloud. In this presentation we report on the direct evidence of the electron cloud in the electron storage ring of the synchrotron light source ANKA (ANgstrom source KArlsruhe).

TUPP024	Electron Cyclotron Resonances in Electron Cloud Dynamics	simulation, resonance, cyclotron, wiggler	1583
	C. M. Celata, M. A. Furman, J.-L. Vay, J. W. Yu LBNL, Berkeley, California
	We report a previously unknown resonance for electron cloud dynamics. The 2D simulation code “POSINST” was used to study the electron cloud buildup at different z positions in the International Linear Collider positron damping ring wiggler. At magnetic field values, B, for which the bunch frequency is an integral multiple of the electron cyclotron frequency an enhancement of up to a factor of 3 in the electron cloud equilibrium density was found. At low magnetic fields the effects of the resonance are prominent, but when B exceeds ~ (2πm_e/el_b), with l_b = bunch length, effects of the resonance disappear. Thus short bunches and low B fields are required for observing the effect. We believe this accounts for the fact that this resonance has not been reported before in the electron cloud literature. The reason for the B field dependence, an explanation of the dynamics, and the results of the 2D simulations and of a single-particle tracking code used to elucidate details of the dynamics will be discussed, along with results from 3D simulations.

TUPP027	Electron Energy Dependence of Scrubbing Efficiency to Mitigate E-cloud Formation in Accelerators	vacuum, simulation, monitoring, luminosity	1592
	R. Cimino, M. Commisso, T. Demma, A. G. Grilli, P. Liu, M. Pietropaoli, V. Sciarra INFN/LNF, Frascati (Roma) V. Baglin CERN, Geneva P. Barone, A. Bonanno INFN Gruppo di Cosenza, Arcavacata di Rende (Cosenza)
	Recently built and planned accelerators, base their ability to reach design parameters, on the capability to reduce Secondary Electron Yield (SEY) during commissioning, hence mitigating the potentially detrimental effects of e-cloud driven machine limitations. This SEY reduction (called "scrubbing"), is due to the fact that the electrons of the cloud, hit the vacuum chamber wall, modifying its surface properties and reducing its SEY. This minimise any disturbing effects of the e-cloud to the beam. "Scrubbing" has been studied only as a function of impinging electron dose. In reality SEY modifications are only studied by bombarding surfaces with 300-500 eV electrons, but no scrubbing dependence on the bombarding electron energy has ever been discussed. The actual energy of the electrons of the cloud hitting the wall in real accelerators has never been measured accurately, while simulations predict very low electron energies (<50 eV). For this reason and given the peculiar behaviour observed for low energy electrons, we decided to study this dependence accurately. Here we present some preliminary results discussing eventual implications to machine commissioning procedures. R. Cimino et al. Phys. Rev. Lett 93, 14801 (2004).

TUPP030	A Formula for the Electron Cloud Map Coefficient in the Presence of a Magnetic Field	simulation, dipole, vacuum, cyclotron	1601
	T. Demma INFN/LNF, Frascati (Roma) S. Petracca U. Sannio, Benevento
	The evolution of the electron density during multibunch electron cloud formation can be reproduced using a bunch-to-bunch iterative map formalism. The reliability of this formalism has been proved for RHIC* and LHC. The coefficients that parameterize the map function are readily obtained by fitting the results of compute-intensive electron cloud simulations. An analytic expression for the linear map coefficient that describes weak cloud behaviour from first principles has been derivied for the case of staight sections of RHIC. In this paper we generalize the model presented in ** to the case of electron cloud evolution in presence of a dipolar magnetic field and compare the results with numerical simulations. U. Iriso and S. Pegg. Phys. Rev. ST Accel. Beams 9, 071002 (2006). T. Demma et al. Phys. Rev. ST Accel. Beams 10,114401 (2007). **U. Iriso and S. Pegg. Proc. of EPAC06, pp. 357-359.

TUPP031	Electron Cloud Simulations for DAΦNE	wiggler, simulation, positron, vacuum	1604
	T. Demma, R. Cimino, S. Guiducci, C. Vaccarezza, M. Zobov INFN/LNF, Frascati (Roma)
	After the first experimental observations compatible with the presence of the electron cloud effect in the DAΦNE positron ring, a systematic study has been performed regarding the electron cloud build-up. To assess the effects of the electron cloud, simulations of the cloud build up were carried out using ECLOUD. In particular, we discuss modifications to the secondary emission model, build up for various filling patterns and different wiggler magnetic field models. The obtained numerical results are compared with experimental observations.

TUPP035	Analysis of Intensity Instability Threshold at Transition in RHIC	octupole, impedance, emittance, coupling	1616
	W. Fischer, I. Blackler, M. Blaskiewicz, P. Cameron, C. Montag, V. Ptitsyn, T. Roser BNL, Upton, Long Island, New York
	The beam intensity of ion beams in RHIC is limited by a fast transverse instability at transition, driven by the machine impedance and electron clouds. For gold and deuteron beams we analyze the dependence of the instability threshold on beam and machine parameters from recent operational data and dedicated experiments. We fit the machine impedance to the experimental data.

TUPP036	"Scrubbing" Process of Cu Surfaces Induced by Electron Bombardment	background, vacuum, simulation, target	1619
	D. R. Grosso, P. Barone, A. Bonanno, M. Camarca, M. Commisso, A. Oliva, F. Xu INFN Gruppo di Cosenza, Arcavacata di Rende (Cosenza) R. Cimino INFN/LNF, Frascati (Roma)
	Energy distribution curves of electrons emitted from accelerator used metal surfaces have been measured for electron irradiation with a primary energy from 20 to 400 eV. We separated the contributions of reflected, rediffused and true-secondary electrons out from the spectra and observed significant differences in their incidence angle dependence. These results provide crucial information on the electron cloud formation in particle accelerators and may shed light on the involved physical mechanisms

TUPP043	Computational Beam Dynamics Studies of Collective Instabilities Observed in SNS	proton, simulation, impedance, kicker	1640
	J. A. Holmes, S. M. Cousineau, V. V. Danilov, A. P. Shishlo ORNL, Oak Ridge, Tennessee L. K. Jain UW/Physics, Waterloo, Ontario
	During the commissioning and early operation of the Spallation Neutron Source, some physcics shifts were set aside for high intensity stability studies. Under certain, especially contrived conditions, a number of beam instabilities were induced. These included both electron cloud and ring impedance driven phenomena. In this paper we apply both simple analytic models and the ORBIT Code to the description and simulation of these observed instabilities.

TUPP045	Studies of Beam Breakup in Dielectric Structures	focusing, simulation, quadrupole, single-bunch	1643
	A. Kanareykin, C.-J. Jing, A. L. Kustov, P. Schoessow Euclid TechLabs, LLC, Solon, Ohio W. Gai, J. G. Power ANL, Argonne, Illinois
	Beam breakup (BBU) effects resulting from parasitic wakefields provide a potentially serious limitation to the performance of dielectric structure based wakefield accelerators. We report on experimental and numerical investigation of BBU and its mitigation. The experimental program focuses on BBU measurements in a number of high gradient and high transformer ratio wakefield devices. New pickup-based beam diagnostics will provide methods for studying parasitic wakefields that are currently unavailable at the AWA facility. The numerical part of this research is based on a particle-Green’s function beam breakup code we are developing that allows rapid, efficient simulation of beam breakup effects in advanced linear accelerators. The goal of this work is to be able to compare the results of detailed experimental measurements with the accurate numerical results and to design an external FODO channel for the control of the beam in the presence of strong transverse wakefields.

TUPP049	Experimental Electron Cloud Studies in the CERN Proton Synchrotron	pick-up, vacuum, extraction, proton	1655
	E. Mahner, F. Caspers, T. Kroyer CERN, Geneva
	Indications for a beam-induced electron cloud build-up are observed since 2000 for the nominal LHC beam in the PS to SPS transfer line and during the last turns before ejection from the PS. A new electron cloud setup was designed, built, and installed in the PS. It contains shielded button-type pickups, a dipole magnet, a vacuum gauge, and a dedicated stripline electrode to experimentally verify the beneficial effect of electron cloud clearing electrodes. During the 2007 run, the electron cloud effect was also clearly observed in the PS and efficient electron cloud suppression has been obtained for negative and positive bias voltages on the clearing electrode. Here, we present electron cloud measurements with different filling patterns and bunch spacings in the PS.

TUPP050	Electron Cloud Mitigation by Fast Bunch Compression in the CERN PS	extraction, synchrotron, pick-up, proton	1658
	H. Damerau, S. Hancock, T. Kroyer, E. Mahner, M. Schokker CERN, Geneva
	A fast transverse instability has been observed with nominal LHC beams in the CERN Proton Synchrotron (PS) in 2006. The instability develops within less than 1 ms, starting when the bunch length decreases below a threshold of 11.5 ns during the RF procedure to shorten the bunches immediately prior to extraction. An alternative longitudinal beam manipulation, double bunch rotation, has been proposed to compress the bunches from 14 ns to the 4 ns required at extraction within 0.9 ms, saving some 4.5 ms with respect to the present compression scheme. The resultant bunch length is found to be equivalent for both schemes. In addition, electron cloud and vacuum measurements confirm that the development of an electron cloud and the onset of an associated fast pressure rise are delayed with the new compression scheme. Beam dynamics simulations and measurements of the double bunch rotation are presented as well as evidence for its beneficial effect from the electron cloud standpoint.

TUPP051	Coupling Impedance of DAΦNE Upgraded Vacuum Chamber	impedance, vacuum, coupling, simulation	1661
	F. Marcellini, D. Alesini, P. Raimondi, G. Sensolini, B. Spataro, A. Stella, S. Tomassini, M. Zobov INFN/LNF, Frascati (Roma)
	The DAΦNE Phi-factory at INFN LNF has been ugraded in the second half of 2007 with a scope to test a recently proposed scheme of crab waist collisions. The vacuum chamber of the collider has been substantially modified: two new low impedance interaction regions have been designed and installed, the new stripline injection kickers have been implemented, the old bellows have been substituted by the new ones and all ion clearing electrodes have been removed. In the paper we present the machine impedance study of these new vacuum chamber components and compare bunch lengthening measurements in the modified DAΦNE with simulation results.

TUPP065	Experimental Study of the Electron Cloud Instability in the CERN-SPS	emittance, injection, simulation, proton	1688
	G. Rumolo, G. Arduini, E. Benedetto, E. Métral, G. Papotti, E. N. Shaposhnikova CERN, Geneva R. Calaga BNL, Upton, Long Island, New York B. Salvant EPFL, Lausanne
	The electron cloud instability limits the performance of many existing proton and positron rings. A simulation study carried out with the HEADTAIL code revealed that the threshold for its onset decreases with increasing beam energy, if the 6D emittance of the bunch is kept constant and the longitudinal matching to the bucket is preserved. Experiments have been carried out at the CERN-SPS to study the dependence of the vertical electron cloud instability on the energy and on the beam size. The reduction of the physical transverse emittance as a function of energy is considered in fact to be the main reason for the unusual dependence of this instability on energy.

TUPP071	Development of TiN Coating System for Beam Ducts of KEK B-factory	cathode, positron, controls, luminosity	1700
	K. Shibata, H. Hisamatsu, K.-I. Kanazawa, M. Shirai, Y. Suetsugu KEK, Ibaraki
	A titanium nitride (TiN) coating system for the copper beam ducts of KEK B-factory (KEKB) was developed to reduce the secondary electron yield (SEY) from the inner surface, which would mitigate the electron cloud instability. The coating was done by DC magnetron sputtering of titanium in argon and nitrogen atmospheres. The duct was set vertically, and a titanium cathode rod was hung from the top on the center axis of the duct. A magnetic field was supplied by a movable solenoid coil placed outside of the duct. Preliminary experiments using small copper samples showed that a 200-nanometer-thick TiN film coated at 150 degree is the best from the viewpoints of SEY and adhesion strength. The SEY of the coated sample decreased to 60% of that of non-coated copper after an electron dose of 0.01 C/mm2, and the maximum SEY was 0.84. Using this system, five ducts with a length of up to 3.6 m were successfully coated. Some of them were installed into the KEKB positron ring last summer, and no problem was found in the following beam operation with a beam current of up to 1.6 A. One coated duct with an electron monitor was installed this winter, and the effect of the coating will be checked.

TUPP075	Numerical Studies of Resistive Wall Effects	vacuum, electromagnetic-fields, emittance, impedance	1709
	A. V. Tsakanian Uni HH, Hamburg M. Dohlus, I. Zagorodnov DESY, Hamburg
	In this paper we describe a new numerical code to calculate wakefields of resistive wall geometries. Our code is based on conformal implicit scheme. It allows to estimate wakefields of very short bunches taking into account transitive effects neglected in the European XFEL impedance budget so far.

TUPP079	Distortion of Crabbed Bunch due to Electron Cloud with Global Crab	betatron, luminosity, optics, positron	1715
	L. Wang, Y. Cai, T. O. Raubenheimer SLAC, Menlo Park, California
	In order to improve the luminosity, crab cavities have been installed in the KEKB HER and LER. Since there is only one crab cavity in each ring, the crab cavity generates a horizontally titled bunch oscillating around the whole ring. The electron cloud in LER (positron beam) may distort the crabbed bunch and cause the luminosity drop. This paper briefly estimates the distortion of positron bunch due to the electron cloud with global crab.

TUPP086	Efficient 3D Space Charge Calculations by Self-adaptive Multigrid Methods Using the Chombo Framework	space-charge, brightness, vacuum, simulation	1730
	C. R. Bahls, G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock
	Current and future accelerator design requires efficient 3D space charge computations for high brightness bunches which should be as precise and fast as possible. One possible approach for space charge calculations is the particle-mesh-method, where the potential is calculated in the rest frame of the bunch by means of Poisson's equation. For an efficient solution of this elliptic PDE an appropriate adaptive discretization of the domain is required. Especially it has to take into account discontinuities in the distribution of the particles. The solution method we investigate in this paper is a self-adaptive multigrid method applying composite grids. To accomplish this, we use the library Chombo* which is being developed as a framework for adaptive multiresolution solvers for elliptic and hyperbolic partial differential equations. *Developed and distributed by the Applied Numerical Algorithms Group of Lawrence Berkeley National Lab., http://seesar.lbl.gov/ANAG/chombo/

TUPP088	Software Components for Electron Cloud Simulation	simulation, proton, space-charge, background	1735
	D. R. Dechow, P. Stoltz Tech-X, Boulder, Colorado J. F. Amundson, P. Spentzouris Fermilab, Batavia, Illinois B. Norris ANL, Argonne, Illinois
	The Synergia2 beam dynamics code is an attempt to incorporate state-of-the-art space charge models from the Impact code into the Chef accelerator tracking code. The need to add new accelerator physics capabilities to the Synergia2 framework has led to software development efforts based on the Common Component Architecture (CCA). The CCA is a specification and a toolset for developing HPC from interchangeable parts, called components. Electron cloud is a potentially limiting effect in the performance of both high-intensity electron and proton machines. The modeling of electron cloud effects is important for the Fermilab main injector. Here, electron cloud effects are expected to play a significant role when the main injector operates in the regime of a high-intensity proton source for the neutrino program. In the ideal case, computational accelerator physicists would like to be able model electron cloud generation and dynamics in a single, self-consistent simulation. As a first step towards creating component-based, electron cloud generation simulations, this work describes a CCA component created from TxPhysics, a library of impact and field ionization routines.

TUPP090	A Kinetic Model of Multipaction for SRF Cavities for Accelerator Driven Sub-Critical System (ADSS)	simulation, electromagnetic-fields, proton, superconductivity	1741
	S. Ghatak, N. Gupta IITK, Kanpur A. S. Dhavale, K. C. Mittal BARC, Mumbai
	This work simulates multipaction in a 700 MHz elliptical SRF cavity. The cavity design was optimized using SUPERFISH. Then the electromagnetic field was re-computed with FEMLAB, a package using the finite element method, to obtain a more accurate field-mapping, and to make the field values available for computation of multipaction. In the multipacting subroutine, electrons were assumed to be released into the system from various points with different initial parameters. The electrons trajectories were tracked until they hit the cavity surface. Leap-frog scheme was used to solve the Lorentz force equation for primary electrons, as it is easy to use and is accurate up to second order. The position, velocity, phase and kinetic energy of primary electrons at each time step were calculated and stored. An interpolation function was used to calculate secondary emission yield (SEY) at different impact energies. With the emission of secondary electrons, their trajectories too were tracked along with primary electrons, in order to identify parameters responsible for multipaction. By repeating this process for large number of electrons, the multipacting trajectories were identified.

TUPP098	The 3D Space Charge Field Solver MOEVE and the 2D Bassetti-Erskine Formula in the Context of Beam - E-cloud Interaction Simulations	positron, simulation, space-charge, damping	1759
	A. Markovik, G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock
	In this paper the fields computed with our 3D space charge field solver MOEVE are compared to those obtained by means of the Bassetti-Erskine formula, which is a widely used 2D approximation of the electric field of a Gaussian bunch. In particular we are interested in the transversal fields of very flat bunches as the ILC or the KEKB positron bunch. Supposing a longitudinal Gaussian distribution of the bunches, we compare the computed transversal fields for a certain line density of the positron bunch. It turns out that the fields from the 2D and the 3D computation coincide very good.

TUPP100	A Four-dimensional Vlasov Solver for Microbunching Instability in the Injection System for X-ray FELs	simulation, collective-effects, emittance, beam-transport	1764
	M. Migliorati, A. Schiavi Rome University La Sapienza, Roma G. Dattoli ENEA C. R. Frascati, Frascati (Roma) M. Venturini LBNL, Berkeley, California
	The phenomenon of microbunching instabilty arises from small charge-density fluctuations in the electron bunches that are amplified by the combined effect of space charge and coherent synchrotron radiation as the beam travels through magnetic compressors. In order to study the coupled longitudinal and transverse beam dynamics we propose to develop a four-dimensional grid-based Vlasov solver. The goal is to give an accurate characterization of the microbunching instability seeded by the random noise present in the initial bunch distribution. Solving directly the Vlasov equation instead of using macroparticle simulations has the advantage of avoiding the statistical fluctuations due to a limited number of macroparticles. Because a Vlasov solver in a high dimension phase-space tends to be particularly time consuming, to be practical a code implementing this method should run on parallel processors. In this paper we report progress toward the realization of such a 4D Vlasov solver.

TUPP103	The Performance of 3D Space Charge Models for High Brightness Electron Bunches	space-charge, simulation, brightness, cathode	1770
	G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock K. Floettmann DESY, Hamburg
	Precise and fast 3D space charge calculations for high brightness, low emittance electron beams are of growing importance for the design of future accelerators and light sources. The program package Astra (A space charge tracking algorithm) has been successfully used in the design of linac and rf photo injector systems. The Astra suite originally developed by K. Flöttmann tracks macro particles through user defined external fields including the space charge field of the particle cloud. In this paper we investigate the performance of the 3D space charge models implemented in Astra. These are the FFT-Poisson solver with the integrated Green's function and the iterative Poisson solver based on the multigrid technique. The numerical tests consider the accuracy of the solvers for model bunches as well as the performance within a typical simulation for the XFEL.

TUPP112	The RADIOTHOMX Project	laser, 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.

TUPP117	Review of Energy Variation Approaches in Medical Accelerators	linac, coupling, radiation, photon	1797
	S. M. Hanna MINA, Danville, California
	Most of cancer Radiation Therapy (RT) machines rely on a linac as the source of the treatment beam which can be an electron beam or an X-ray beam. In either case, an approach to vary the energy of the linac’s output beam may be needed to target cancer tumors of different depths. Over the last two decades, multiple approaches for medical linac energy variation were proposed and some of them have been developed and implemented clinically. The most direct and conventional technique is to vary the amount of the RF power delivered to the linac and hence the energy output as required by the treatment plan. A second approach involves keeping the RF power delivered to the linac fixed but varying the power delivered to different sections of the linac by utilizing a mechanical or an electronic switch that controls the power distribution inside the linac. A third approach is to use two separate linac sections. The first section receives a fixed amount of RF power while the RF power delivered to second section is controlled using conventional microwave power splitting techniques. In this paper we will review the above approaches and discuss the advantages and disadvantage of each technique.

TUPP121	Spatial Resolution and Contrast of the Intensity Modulated Electron Beam by the Photocathode RF Gun for the Radiation Therapy	gun, laser, 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.

TUPP139	Variable Energy 2-MeV S-Band Linac for X-ray and Other Applications	linac, emittance, target, simulation	1845
	H. Bender, D. D. Schwellenbach, R. Sturgess, C. P. Trainham NSTec, Los Alamos, New Mexico J. M. Potter JP Accelerator Works, Los Alamos, New Mexico
	We will describe the design and operation of a compact, 2-MeV, S-band linear accelerator (linac) with variable energy tuning and short-pulse operation down to 15 ps with 100-A peak current. The design consists of a buncher cavity for short-pulse operation and two coupled resonator sections for acceleration. Single-pulse operation is accomplished through a fast injector system with a 219-MHz subharmonic buncher. The machine is intended to support a variety of applications, such as X-ray and electron beam diagnostic development and, recently, electron diffraction studies of phase transitions in shocked materials.

TUPP141	Electron Accelerators for Cleaning Flue Gases and for Oil Liquefaction	radiation, cathode, vacuum, plasma	1848
	S. Korenev, R. P. Johnson Muons, Inc, Batavia
	High-power electron beams can be used to reduce the environmental impact of coal and oil-fired power generating plants by removing harmful materials from flue gases. This technology has been tested in the laboratory and at smaller industrial levels, but to make it economically attractive, the accelerator costs must be reduced and the efficiency must be increased for removing toxic components in low concentrations. We propose a simple electron accelerator with a wide beam to reduce costs. To remove toxic materials we propose a plasma reactor for desulfurization and selective catalytic reduction. The designs of 0.5 to 1.0 MeV accelerators with 20 to 100 kW average power are considered, along with the design of a plasma reactor for flue gas treatment. The design of a pilot facility for the oil industry is also presented.

TUPP143	Collective Ionization by Attosecond Electron Bunches	plasma, target, ion, collective-effects	1851
	A. Ogata, T. Kondoh, K. Norizawa, J. Yang, Y. Yoshida ISIR, Osaka
	Present accelerator technology has realized linac bunch length on the order of femtosecond. If the bunch length becomes onto the order of attosecond, its inverse is comparable to the ionization frequency; ionization potential divided by Plank's constant. The stopping power then becomes proportional to square of the number of bunch electrons. Such a bunch ionizes the target collectively. This collective, or coherent ionization will provide us plenty of applications including unknown ones at the present. This phenomenon has historically been expected in cluster beams, which can be regarded as ultra-short bunches. The present paper adapts formalism of stopping power of a medium characterized by a dielectric function against cluster beams to that against electron bunches. It then describes some numerical calculations on the collective ionization by the attosecond electron bunches.

TUPP148	Multigrid Negative Ion Source Test and Modeling	ion, plasma, ion-source, simulation	1857
	M. Cavenago INFN/LNL, Legnaro, Padova V. Antoni, G. Serianni, P. Veltri Consorzio RFX, Euratom ENEA Association, Padova
	Negative ion sources are a fundamental ingredient of neutral ion beam injectors for tokamak, like the ITER project and beyond. While detail of formation of negative ions and meniscus of the plasma beam interface at source extraction at source extraction is still debated, reasonable modelling of the beam extraction is well possible. A project of a small source (up to 9 beamlet of 15 mA each of H-, 60 kV acceleration voltage) is here described, and relevant modeling tools are reviewed. Power load deposition on the extraction grid (about 1.5 kW total) and on the source walls (comparable) need accurate cooling design. The extracted beam is direclty useful for wall damage studies.

TUPP150	The Radiatron: A High Average Current Betatron for Industrial and Security Applications	betatron, acceleration, focusing, injection	1860
	S. Boucher, R. B. Agustsson, P. Frigola, A. Y. Murokh, M. Ruelas RadiaBeam, Los Angeles F. H. O'Shea, J. B. Rosenzweig, G. Travish UCLA, Los Angeles, California
	The fixed-field alternating-gradient (FFAG) betatron has emerged as a viable alternative to RF linacs as a source of high-energy radiation for industrial and security applications. For industrial applications, high average currents at modest relativistic electron beam energies, typically in the 5 to 10 MeV range, are desired for medical product sterilization, food irradiation and materials processing. For security applications, high power x-rays in the 3 to 20 MeV range are needed for rapid screening of cargo containers and vehicles. In a FFAG betatron, high-power output is possible due to high duty factor and fast acceleration cycle: electrons are injected and accelerated in a quasi-CW mode while being confined and focused in the fixed-field alternating-gradient lattice. The beam is accelerated via magnetic induction from a betatron core made with modern low-loss magnetic materials. Here we present the design and status of a prototype FFAG betatron, called the RadiaTron, as well as future prospects for these machines.

TUPP151	A High Intensity Positron Source at Saclay: The SOPHI Project	positron, target, linac, ion	1863
	O. Delferriere, V. Blideanu, M. Carty, A. Curtoni, L. Liszkay, P. Perez, J. M. Rey, N. Ruiz, Y. Sauce CEA, Gif-sur-Yvette F. Forest, J. L. Lancelot, D. Neuveglise Sigmaphi, Vannes
	One of the fundamental questions of todays physics concerns the action of gravity upon antimatter. No experimental direct measurement has ever been successfully performed with antimatter particles. An R&D program has been launched at IRFU (CEA/Saclay) to demonstrate the feasibility of the production of antihydrogen (H) with the use of a target of positronium (Ps) atoms. This target, when bombarded with antiprotons, should allow combining its positrons with the incoming antiprotons and create H atoms and H⁺ ions. This experiment needs a large amount of Ps atoms, thus an intense source of positrons is necessary. We are building the SOPHI experiment in Saclay, based on a small 5 MeV electron linac to produce positrons via pair production on a tungsten target. This device should provide 10⁸ slow e+/s, i.e. a factor 300 greater than the strongest activity Na22 based setups. The SOPHI system has been finalized in 2006 and the main components have been studied and built during 2007. The experiment is currently assembled and first results are expected in June 2008. The Linac, beam production and transport system will be presented, and first positron production rate measurements reported.

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

TUPP157	Commissioning of L-band Electron Accelerator for Industrial Applications	klystron, bunching, power-supply, gun	1875
	S. H. Kim, M.-H. Cho, W. Namkung, H. R. Yang POSTECH, Pohang, Kyungbuk J. Jang, S. D. Jang, S. J. Kwon, J.-S. Oh, S. J. Park, Y. G. Son PAL, Pohang, Kyungbuk
	An intense L-band electron linear accelerator is under construction at CESC (Cheorwon Electron-beam Service Center) for industrial applications. It is capable of producing 10-MeV electron beams with a 30-kW average beam power. For high-power capability, we adopted 1.3 GHz, and the RF source is a 25-MW pulsed klystron with a 60-kW average RF output power. A pre-buncher is used before the bunching section, which is built-in with the regular accelerating sections. The accelerating structure is a disk-loaded waveguide with a constant-impedance operated in the 2π/3-mode. It is to be operated under the fully beam-loaded condition for high average power with the 6-μs pulse length and the 350-Hz repetition rate. In this paper, we present details of the accelerator system and commissioning results.

TUPP158	Development of Laser System for Compact Laser Compton Scattering X-ray Source	laser, 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.

TUPP159	Dual Energy Material Recognition: Preliminary Results Obtained with the Radio-tomographic System Hosted in Messina	simulation, linac, photon, target	1881
	D. Loria, L. Auditore, R. C. Barnà, U. Emanuele, E. Morgana, A. Trifirò, M. Trimarchi INFN - Gruppo Messina, S. Agata, Messina M. Carpinelli INFN-Cagliari, Monserrato (Cagliari) A. Franconieri, M. Gambaccini INFN-Ferrara, Ferrara
	Dual Energy technique is a very powerful tool for material recognition. It typically involves X-ray energy below 1 MeV, thus limiting to few mm the thickness of the inspected heavy materials. However, it would be interesting to investigate the chance to extend this technique to higher energies, to allow recognition of thick heavy samples too. Encouraging preliminary tests performed by means of the radio-tomographic system based on a 5 MeV electron linac have suggested to develop a dual energy technique for high energy x-ray beams. This can be done because first experimental tests have confirmed the chance to vary the electron beam energy in a continuous way. As a consequence, bremsstrahlung beams with different end points can be produced, thus allowing to work with different x-ray transmissions. The composition of two different energies X-ray transmission results, allows to perform material recognition. By means of the MCNP4C2 code, simulations have been performed to evaluate the theoretical x-ray transmission in different materials and thickness. These results allow us to choose two x-ray energies providing the best results in order to perform material recognition.

TUPP161	60 keV 30 kW Electron Beam Facility for Electron Beam Technology	controls, cathode, gun, focusing	1887
	Yu. I. Semenov, V. E. Akimov, M. A. Batazova, B. A. Dovzhenko, V. V. Ershov, A. R. Frolov, I. A. Gusev, Ye. A. Gusev, V. M. Konstantinov, N. Kh. Kot, V. R. Kozak, E. A. Kuper, G. I. Kuznetsov, P. V. Logatchev, V. R. Mamkin, A. S. Medvedko, I. V. Nikolaev, A. Yu. Protopopov, D. N. Pureskin, V. V. Repkov, A. N. Selivanov, D. V. Senkov, A. S. Tsyganov, A. A. Zharikov BINP SB RAS, Novosibirsk
	At the Budker Institute of Nuclear Physics, Novosibirsk, the 60 keV 30 kW electron beam facility for electron beam technology has been developed. The electron gun provides continuous or modulated beam within the current range from 1 mA up to 500 mA. The optical system allows both static and dynamic focusing of the electron beam within the 50/500 mm range of distance from the gun outlet, the beam scanning and its parallel displacement from the optical axis. The electron gun facility is controlled by the computer via the CAN interface. This paper presents the general description of the facility, its block diagram and main parameters.

WEOBG02	Experimental Results of a Plasma Wakefield Accelerator Using Multiple Electron Bunches	plasma, resonance, simulation, diagnostics	1912
	E. Kallos, T. C. Katsouleas, P. Muggli USC, Los Angeles, California W. D. Kimura STI, Washington K. Kusche, J. H. Park, I. Pogorelsky, D. Stolyarov, V. Yakimenko BNL, Upton, Long Island, New York
	We present some preliminary experimental results of a plasma wakefield accelerator technique which utilizes multiple electron bunches in order to drive a plasma wave. The experiments were performed at the Accelerator Test Facility of Brookhaven National Laboratory where 5-8 equidistant bunches with a spacing which was varied between 100-250 m were fed into a 6mm-long capillary discharge plasma. By varying the time delay of the bunches with respect to the discharge different plasma densities could be tuned, and the effects of the plasma on the bunches were recorded. Such multiple bunch schemes are of great interest because they can provide increased efficiencies and high transformer ratios for advanced accelerators.
	Slides

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

WEOBG04	First Experimental Results from DEGAS, the Quantum Limited Brightness Electron Source	laser, 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, laser, radiation	1939
	J. N. Galayda SLAC, Menlo Park, California
	The Linac Coherent Light Source (LCLS) is a free-electron laser facility in construction at Stanford Linear Accelerator Center. It is designed to operate in the wavelength range 0.15-1.5 nanometers. At the time of this conference, civil construction of new tunnels and buildings is complete, the necessary modifications to the SLAC linac are complete, and the undulator system and x-ray optics/diagnostics are being installed. The electron gun, 135 MeV injector linac and 250 MeV bunch compressor were commissioned in 2007. Accelerator commissioning activities are presently devoted to the achievement of performance goals for the completed linac. R. Akre, et al., "Commissioning the LCLS Injector", submitted to PRSTAB, 2007
	Slides

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

WEOAM02	A Scheme for Stabilization of Output Power of an X-ray SASE FEL	undulator, laser, radiation, linac	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

WEOBM03	Development of a High Resolution Camera and Observations of Superconducting Cavities	superconductivity, linac, superconducting-RF	1956
	Y. Iwashita, Y. Tajima Kyoto ICR, Uji, Kyoto H. Hayano KEK, Ibaraki
	An inspection system of the interior surface of superconducting RF cavities is developed in order to study the relation between the achievable field gradient and the defects of the interior surface. The achieved resolution is about 7 microns/pixel. So far there are good correlations between locations identified by a thermometry measurements and positions of defects found by this system. The heights or depths can be also estimated by measuring wall gradients for some well-conditioned defects. The detailed system and the data obtained from the system will be described.
	Slides

WEIM04	Highly Customized Industrialized Linacs for Applications in Scientific Research	linac, proton, vacuum, RF-structure	1967
	C. Piel ACCEL, Bergisch Gladbach
	Industrial capabilities and experience in linac design and manufacturing shall be given for the various types of scientific applications. Furthermore the process from linac contracting through establishing a project team and adequate human and machine ressources for fulfilling the technical, schedule and pricing requirements shall be described.
	Slides

WEPC012	Commissioning and Operation of the Metrology Light Source (MLS)	injection, accumulation, ion, storage-ring	2010
	J. Feikes, M. Abo-Bakr, K. B. Buerkmann-Gehrlein, M. V. Hartrott, J. Rahn, G. Wuestefeld BESSY GmbH, Berlin R. Klein, G. Ulm PTB, Berlin
	The Metrology Light Source (MLS) is dedicated to metrological and technological developments in the UV and EUV spectral range and in the IR and THz region. The new electron storage ring of the Physikalisch-Technische Bundesanstalt (PTB) is located next to the BESSY II storage ring in Berlin - Adlershof. The MLS with its 48 m circumference can be operated at any electron beam energy between 105 MeV and 630 MeV. The electron beam currents vary from 1 pA (one stored electron) up to 200 mA. These specific modes of operation were achieved during the initial one year phase of the commissioning of the storage ring until April 2008, when the regular MLS user operation started. The basis for this success was the previously commissioned microtron which is the main part of the injection system.

WEPC015	Baseline Design of HLS Linac Upgrade	linac, klystron, quadrupole, gun	2019
	G. Feng, W. Li, L. Shang, L. Wang, C.-F. Wu, H. Xu, S. C. Zhang USTC/NSRL, Hefei, Anhui
	The existing 200MeV linac of Hefei Light Source (HLS) mainly consists of electron gun, prebuncher, buncher, one 3m S-band linac section, and four 6m S-band linac sections. Energy gain of electron beam at the end of the linac is 200MeV and energy spread is ±0.8%. In order to improve the electron beam quality, An upgrade project is required. Four 80MW klystrons will be used to instead the old ones, which can improve the beam energy stability. This upgrade can also make it possible to increase the linac energy from 200 MeV to 400 MeV without changing the accelerating structure. In the meantime, New operation modes of HLS linac has been found by extensive computer modelling and optimization. Electron beam dynamics simulation from electron gun to the end of linac has been given, which considering space charge effects and wakefields.

WEPC017	Short X-ray Pulse Generation in Taiwan Photon Source Using Deflecting Cavity	photon, emittance, lattice, radiation	2025
	H. Ghasem IPM, Tehran G.-H. Luo NSRRC, Hsinchu
	We have purposed to use deflecting cavity for short X-ray pulses production in 3 GeV Taiwan Photon Source (TPS). Typical electron bunch length in TPS for 1.1MV RF gap voltage is about 5.7mm. Deflecting cavity generates correlation between longitudinal position and vertical momentum of particles in a bunch. Vertical kick of particle separates the photons that emit from ID vertically. Slit and asymmetric crystal in TPS beam line are used to compress the photon pulse duration. For a 60 m beam line of TPS, the operating of deflecting cavity up to 6MV voltage and eighth harmonic yields an FWHM pulse duration of radiated X-ray of about 0.48 ps for users.

WEPC026	Laser – Beam Interaction and Calculation of the Sliced Bunch Radiation Spectra for the SLS FEMTO Beam Line	laser, 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.

WEPC027	Coherent THz Radiation at ELETTRA	radiation, synchrotron, synchrotron-radiation, single-bunch	2043
	E. Karantzoulis, G. Penco, A. Perucchi ELETTRA, Basovizza, Trieste S. Lupi Coherentia, Naples
	Coherent infra red radiation (CIR) has been observed since some time at ELETTRA under several machine parameter settings in the beam-line SISSI. Effort has been made to produce a “stable” THz signal for experimental use. The description of the machine settings to that end and the measurements performed are presented and discussed.

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

WEPC032	Absolute Measurement of the MLS Storage Ring Parameters	photon, storage-ring, radiation, induction	2055
	R. Klein, G. Brandt, R. Fliegauf, A. Hoehl, R. Müller, R. Thornagel, G. Ulm PTB, Berlin M. Abo-Bakr, K. B. Buerkmann-Gehrlein, J. Feikes, M. V. Hartrott, K. Holldack, J. Rahn, G. Wuestefeld BESSY GmbH, Berlin
	The Metrology Light Source (MLS), the new electron storage ring of the Physikalisch-Technische Bundesanstalt (PTB) located next to BESSY II in Berlin - Adlershof is dedicated to metrology and technology development in the UV and EUV spectral range as well as in the IR and THz region. The MLS can be operated at various electron beam energies up to approx. 600 MeV and at electron beam currents varying from 1 pA (one stored electron) up to 200 mA and is optimized for the generation of coherent synchrotron radiation. Of special interest for PTB is the operation of the MLS as a primary radiation source standard from the visible up to the X-ray region. Therefore the MLS is equipped with all the instrumentation necessary to measure the storage ring parameters needed for the calculation of the spectral photon flux according to the Schwinger theory with low uncertainty. The instrumentation and measurement results for the determination of the storage ring parameters are presented.

WEPC033	Coherent Synchrotron Radiation at the Metrology Light Source of the PTB	radiation, synchrotron, synchrotron-radiation, storage-ring	2058
	R. Müller, A. Hoehl, R. Klein, G. Ulm PTB, Berlin M. Abo-Bakr, K. B. Buerkmann-Gehrlein, J. Feikes, M. V. Hartrott, J. S. Lee, J. Rahn, U. Schade, G. Wuestefeld BESSY GmbH, Berlin
	The Physikalisch-Technische Bundesanstalt (PTB), the German national metrology institute, has set up a low-energy electron storage ring in Berlin-Adlershof in close cooperation with the BESSY GmbH. The new storage ring, named Metrology Light Source (MLS), is mainly dedicated to metrology and technological developments in the EUV, VUV, and IR spectral range. Additionally, the MLS is the first machine designed and prepared for a special machine optics mode (low-alpha operation mode) based on an octupole correction scheme, for the production of coherent synchrotron radiation in the FIR and THz region. Two beamlines dedicated to the use of IR synchrotron radiation are now under commissioning: an IR bending magnet beamline optimized for the MIR to FIR and an IR edge radiation beamline. We report the status of the MLS operated in the low alpha mode and present first results from the commissioning.

WEPC040	Commissioning of the SSRF Booster	booster, linac, dipole, synchrotron	2073
	H. H. Li, Q. Gu, D. M. Li, L. G. Liu, D. Wang, Z. T. Zhao SINAP, Shanghai
	The SSRF Booster, designed to accelerate the electrons from 150MeV to 3.5GeV, is a FODO structure synchrotron with 180m circumference and 2Hz repetition rate. The commissioning of the SSRF booster from the LTB transfer line started on Sept. 30th evening, 2007, the first turns of beam in the booster was obtained in 20 hours. With about 60 hours effective commissioning effort, the electrons were accelerated to 3.5GeV on October 5th morning, 2007. And then the first 3.5GeV beam was extracted to BTS transfer line on October 30th, 2007. In this paper, the SSRF booster is introduced and its commissioning results are presented.

WEPC044	Top-Up Safety Simulations for the Diamond Storage Ring	sextupole, simulation, storage-ring, quadrupole	2085
	I. P.S. Martin, C. P. Bailey, E. C. Longhi, R. P. Walker Diamond, Oxfordshire R. Bartolini, I. P.S. Martin JAI, Oxford
	To ensure that it is not possible for a train of injected electron bunches to pass down an open beam-line during top-up operation at the Diamond Light Source, an extensive program of tracking studies has been performed. Various error scenarios have been investigated, with realistic magnetic field, trajectory, aperture and energy errors all taken into account. We describe the tracking methods used, scenarios considered and the interlocks required in order to maintain user safety during top-up operation.

WEPC047	Modeling the Shape of Coherent THz Pulses Emitted by Short Bunches in an Electron Storage Ring	radiation, synchrotron, synchrotron-radiation, storage-ring	2094
	A.-S. Müller, S. Casalbuoni, M. Fitterer, E. Huttel, Y.-L. Mathis FZK, Karlsruhe M. T. Schmelling MPI-K, Heidelberg
	A sufficiently short electron bunch will emit coherent synchrotron radiation of wavelengths equal to or larger than the bunch length. The shape of the emitted THz pulse depends amongst other things on the original shape and length of the bunch’s charge distribution. A Michelson interferogram of the THz signal therefore contains information on the generating bunch. However, systematic effects make a bunch length measurement based on that technique non-trivial. In order to understand the variables involved, an analytical model of the pulse generation is needed. In this paper, a derivation of the THz pulse shape form first principles with special emphasis in the time domain is presented. The impact of charge distribution parameters on the Michelson interferogram is discussed.

WEPC053	An Experimental Study of Radiation-induced Demagnetization of Insertion Device Permanent Magnets	radiation, proton, insertion, insertion-device	2112
	N. Simos, P. K. Job BNL, Upton, Long Island, New York N. V. Mokhov Fermilab, Batavia, Illinois
	High brilliance in the 3GeV new light source NSLS II is obtained from the high magnetic fields in insertion devices (ID). The beam lifetime is limited to 3h by single Coulomb scattering in the Bunch (Touschek effect). This effect occurs everywhere around the circumference and there is unavoidable beam loss in the adjacent low-aperture insertion devices. This raises the issue of degradation and damage of the permanent magnetic material by irradiation with high energy electrons and corresponding shower particles. It is expected that IDs, especially those in-vacuum, would experience changes resulting from exposure to gamma rays, x-rays, electrons and neutrons. By expanding an on-going material radiation damage study at BNL the demagnetization effect of irradiation consisting primarily of neutrons, gamma rays and electrons on a set of NdFeB magnets is studied. Integrated doses of several Mrad to a few Grad were achieved at the BNL Isotope Facility with a 112-MeV, 90-uA proton beam. Detailed information on dose distributions and particle energy spectra on the NdFeB magnets was obtained with the MARS15 Monte-Carlo code. This paper summarizes the results of this study. Work performed under the auspices of the US DOE.

WEPC060	Studies on the Beam Current Dependent Phenomena in the BEPC-II Storage Rings	vacuum, single-bunch, luminosity, synchrotron	2130
	Q. Qin, N. Huang, W. B. Liu, Y. D. Liu, Y. M. Peng, J. Qiu, D. Wang, J. Q. Wang, N. Wang, X. H. Wang, Y. Wei, X. M. Wen, J. Xing, G. Xu, C. H. Yu, C. Zhang, Y. Zhang, Z. Zhao, D. M. Zhou IHEP Beijing, Beijing
	The upgrade project of the Beijing Electron Positron Collider (BEPC-II) has been being commissioned since Nov. 2006. Besides the commissioning of the luminosity, which is expected to be 100 times higher than the BEPC, the BEPC-II also provided beam to the synchrotron radiation users as a light source during these two years. Some beam current dependent phenomena, such as bunch lengthening, single beam instabilities, blow-up in collision, etc., in both collision and synchrotron radiation modes are observed in the machine performance. In this paper, some observations and analyses on these phenomena are given.

WEPC062	The SRS at Daresbury Laboratory: a Eulogy to the World's First Dedicated High-energy Synchrotron Radiation Source	storage-ring, synchrotron, lattice, wiggler	2133
	D. J. Holder, N. G. Wyles STFC/DL/ASTeC, Daresbury, Warrington, Cheshire P. D. Quinn STFC/DL/SRD, Daresbury, Warrington, Cheshire
	2008 marks the last year of operation of the Synchrotron Radiation Source (SRS) at Daresbury Laboratory, which circulated its first 2 GeV beam in 1981. This paper provides a look back at the significant milestones passed on the way and records the achievements of many of those involved in its thirty-year programme. Many of the technologies and techniques developed at the SRS at Daresbury are now standard practice at synchrotron light sources around the world; and there are few light source laboratories that do not benefit from the skills of someone who spent their formative years working on the SRS. The provision of synchrotron light for the UK is now being met by DIAMOND, whose success is a testament to the skills of its designers, honed as they were on the SRS at Daresbury. These skills are now being used to design the UK’s next-generation light source, to provide the pulsed and longer-wavelength light that DIAMOND cannot.

WEPC069	A Possible THz Radiation Source with a Train of Short Pulses in the SPARC High Brightness Photoinjector	radiation, cathode, simulation, linac	2154
	M. Boscolo, M. Castellano, E. Chiadroni, M. Ferrario, A. Stella, C. Vaccarezza INFN/LNF, Frascati (Roma) V. Petrillo Universita' degli Studi di Milano, Milano
	A radiofrequency electron gun followed by a compressor can generate trains of THz sub-picosecond electron pulses by illuminating the photocathode with a comb laser pulse. This structure of the beam can be used to produce coherent radiation. A feasibility study for a possible experiment at SPARC to be realized with the addition of a dedicated magnetic chicane is discussed. An optimization study of a magnetic chicane with a negative and variable R56 is studied, together with a set of parameters relative to the SPARC machine with the intent of demonstrating the feasibility of this experiment. The dynamics is studied within the SPARC system with the PARMELA code and with the RETAR code for the evaluation of the radiation.

WEPC071	Installation and Commissioning of the 100 MeV Preinjector Linac of the New Elettra Injector	gun, booster, linac, klystron	2160
	G. D'Auria, P. Borsi, A. Carniel, P. Delgiusto, O. Ferrando, A. Franceschinis, M. M. Milloch, A. Milocco, F. Pribaz, N. Sodomaco, M. Stefanutti, L. Veljak, D. Wang ELETTRA, Basovizza, Trieste L. Picardi, C. Ronsivalle ENEA C. R. Frascati, Frascati (Roma)
	A new full energy injector has been installed and commissioned at Sincrotrone Trieste, the Italian Synchrotron Light Source Facility in Trieste. It consists of a 100 MeV Preinjector Linac (PL) followed by a 2.5 GeV Booster Synchrotron (BS), that will fill the Elettra Storage Ring (SR) with 2.0 GeV and 2.4 GeV electrons. Here a complete description of the preinjector linac and its characterization in terms of beam parameters will be presented and discussed.

WEPC082	Technical Considerations of the TPS Linac	linac, controls, synchrotron, bunching	2186
	A. P. Lee, H.-P. Chang, J. Chen, C.-S. Fann, K. T. Hsu, S. Y. Hsu, W. K. Lau, K.-K. Lin, K.-B. Liu, Y.-C. Liu, C. Y. Wu NSRRC, Hsinchu
	The technical considerations of the TPS (Taiwan Photon Source) linac will be presented in this report. A 150 MeV turn-key linac is chosen in this case in order to provide the ease of injection into the booster in which the electron energy will be raised up to 3 GeV. This linac will be similar to that equipping at recently commissioned synchrotron light sources. The major beam parameters are derived from the booster and storage ring injection requirements. The beam diagnostics arrangement for linac commissioning purpose will be briefly described.

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

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

WEPC103	Design of a Cold Vacuum Chamber for Diagnostics	vacuum, synchrotron, diagnostics, storage-ring	2240
	S. Casalbuoni, T. Baumbach, A. W. Grau, M. Hagelstein, R. Rossmanith FZK, Karlsruhe V. Baglin, B. Jenninger CERN, Geneva R. Cimino INFN/LNF, Frascati (Roma) M. P. Cox Diamond, Oxfordshire E. M. Mashkina University of Erlangen-Nürnberg, Physikalisches Institut II, Erlangen E. J. Wallén MAX-lab, Lund R. Weigel Max-Planck Institute for Metal Research, Stuttgart
	Preliminary studies performed with the cold bore superconducting undulator installed in the ANKA storage ring suggest that the beam heat load is mainly due to the electron wall bombardment. Low energy electrons (few eV) are accelerated by the electric field of the beam to the wall of the vacuum chamber, induce non-thermal outgassing from the cryogenic surface and heat the undulator. In this contribution we report on the design of a cold vacuum chamber for diagnostics to be installed in the ANKA (ANgstrom source KArlsruhe) storage ring and possibly in third generation light sources. The diagnostics implemented are: retarding field analyzers to measure the electron energy and flux, temperature sensors to measure the total heat load, pressure gauges, and a mass spectrometer to measure the gas content. The aim of this device is to gain a deeper understanding on the heat load mechanisms to a cold vacuum chamber in a storage ring and find effective remedies. The outcome of the study is of relevance for the design and operation of cold bore superconducting insertion devices in synchrotron light sources.

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

WEPC110	Development of a Conventional Multipole Wiggler MPW-80	wiggler, multipole, synchrotron, power-supply	2258
	D. J. Waterman, A. Deyhim, J. Kulesza, E. Van Every Advanced Design Consulting, Inc, Lansing, New York K. I. Blomqvist MAX-lab, Lund
	The design for an 80 mm period hybrid wiggler is presented. The design requirements and mechanical difficulties for holding, positioning, and driving the magnetic arrays are explored. The structural and finite element analysis, magnetic design, and electrical considerations that influenced the design are then analyzed. This wiggler will be installed at ALBA a new synchrotron radiation source being built at the site of the Centre Direccional in Cerdanyola del Vallès, nearby Barcelona, and will produce ultra-violet and X-ray beams of exceptional brightness. The facility will comprise a 3 GeV electron storage ring, injected from a ~100 MeV linac through a full energy booster synchrotron.

WEPC112	The Acceptance and Photon Beam Formation in SLS FEMTO Beamline	laser, radiation, background, 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.

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

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

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

WEPC124	Magnetic Measurement System for the SPARC Insertion Devices	undulator, laser, controls, alignment	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, laser, wiggler, radiation	2303
	S. Sandru UPG, Ploiesti V. Babin INOE, Bucharest M. R. Leonovici Bucharest University, Faculty of Physics, Bucharest-Magurele V. I.R. Niculescu INFLPR, Bucharest - Magurele
	A new undulator structure for free electron lasers was presented. Current BISCUIT devices produce magnetic fields which are spatially periodic. The current structure was in the shape of wires stacks . The current has alternating directions. The magnetic field components for each wire presents symmetry with two axis. The BISCUIT undulator transverse cross-section (in arbitrary units) is a function depending directly on cosine (for x component) and sine (for y component) and inverse on the square root of the sum of forth power of sine and cosine. The z component is a constant. The Biot - Savart law was numerically evaluated. The magnetic field is longitudinal and easily adjustable with the current. The versatility of the constant parameter covers longitudinal undulator or wiggler design for one or two beams devices with transverse momenta.

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

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

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

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

WEPC156	Development and Adjustment of the EMMA Quadrupole Magnets	quadrupole, multipole, dipole, controls	2374
	N. Marks, B. J.A. Shepherd STFC/DL/ASTeC, Daresbury, Warrington, Cheshire M. J. Crawley, F. T.D. Goldie, B. Leigh Tesla Engineering Limited, West-Sussex
	The non-scaling FFAG EMMA, now under construction at STFC’s Daresbury Laboratory, requires 84 quadrupoles. Because of the unusual nature of these magnets, prototypes for the F and the D type quadrupoles were required. These magnets were ordered from and constructed and measured by Tesla Engineering. Subsequently, design changes have been made and modifications to the prototypes carried out. The paper will give engineering details of these prototypes, of the measurement results obtained using a rotating coil magnetometer and subsequent adjustments to clamp plates and pole profiles needed to obtain optimum three dimensional gradient quality. As a result of these developments, the construction of the magnets for the complete ring is now underway. B. J.A. Shepherd & N. Marks, “Quadrupole Magnets For The 20MeV FFAG, ‘EMMA’”, PAC 2007 (MOPAN107).

WEPC159	Compact Design of Race-track Microtron Magnets	focusing, linac, microtron, induction	2380
	J. P. Rigla, Yu. A. Kubyshin UPC, Barcelona S. Ferrer ALBA, Bellaterra A. V. Poseryaev, V. I. Shvedunov MSU, Moscow
	A novel design of the end magnets for race-track microtrons (RTMs) is proposed. It consists of four-poles with the REPM material being used as a source of the magnetic field. For a proper choice of parameters of such magnetic system it can provide both the closure of the first orbit after beam reflection and required focusing properties. It is shown that such end magnet can be made quite compact thus allowing to build miniature RTMs. The procedure of design of the four-pole magnetic system and its optimization using the ANSYS code is described in detail.

WEPP002	The Effect of Head-on Beam-beam Compensation on the Stochastic Boundaries and Particle Diffusion in RHIC	emittance, proton, simulation, resonance	2521
	N. P. Abreu, W. Fischer, Y. Luo, G. Robert-Demolaize BNL, Upton, Long Island, New York
	To compensate the effects from the head-on beam-beam interactions in the polarized proton operation in the Relativistic Heavy Ion Collider (RHIC), an electron lens (e-lens) is proposed to collide head-on with the proton beam. We used an extended version of SixTrack for multiparticle beam-beam simulation in order to study the effect of the e-lens on the stochastic boundary and also on diffusion. The stochastic boundary was analyzed using Lypunov exponents and the diffusion was characterized as the average rms spread of the action after 10⁴ turns. For both studies the simulations were performed with and without the e-lens and with full and partial compensation.

WEPP016	FEL-based Coherent Electron Cooling for High-energy Hadron Colliders	hadron, collider, emittance, luminosity	2560
	V. Litvinenko BNL, Upton, Long Island, New York Y. S. Derbenev Jefferson Lab, Newport News, Virginia
	Cooling intense high-energy hadron beams remains a major challenge in modern accelerator physics. Synchrotron radiation of such beams is too feeble and two common methods, stochastic and electron cooling, are not efficient in providing significant cooling for high energy hadron, especially proton, colliders. In this paper we discuss a practical scheme of Coherent Electron Cooling, which promises short cooling times (below one hour) for intense proton beams in RHIC at 250 GeV or in LHC at 7 TeV. Coherent Electron Cooling was suggested early 1980s as a possibility for using various microwave instabilities in an electron beam to enhance its interaction with hadrons. The capabilities of present-day accelerator technology, ERLs, and high-gain Free-Electron Lasers (FELs), finally caught up with the idea and provided the all necessary ingredients for realizing such a process at energies typical for modern high energy hadron colliders. In this paper, we discuss the principles, the main limitations of this scheme and present some predictions for Coherent Electron Cooling in RHIC and the LHC operating with ions or protons. V. N. Litvinenko, Y. S. Derbenev, Proc. 29th Int. FEL Conference, Novosibirsk, August, 2007. **Y. S. Derbenev, Proc. of 7th All-Union Conf. on Charged Particle Accelerators, October 1980, Dubna, 269.

WEPP029	Project of the Nuclotron-based Ion Collider Facility (NICA) at JINR	ion, collider, luminosity, heavy-ion	2581
	G. V. Trubnikov, N. N. Agapov, V. Alexandrov, A. V. Butenko, E. E. Donets, A. V. Eliseev, A. Govorov, V. Kekelidze, H. G. Khodzhibagiyan, V. Kobets, A. D. Kovalenko, O. S. Kozlov, A. Kuznetsov, I. N. Meshkov, V. A. Mikhaylov, V. Monchinsky, V. Shevtsov, A. O. Sidorin, A. N. Sissakian, A. V. Smirnov, A. Sorin, V. Toneev, V. Volkov, V. Zhabitsky JINR, Dubna, Moscow Region O. I. Brovko, I. Issinsky JINR/LHE, Moscow
	The Nuclotron-based Ion Collider fAcility (NICA) is the new accelerator complex being constructed at JINR aimed to provide collider experiments with heavy ions up to uranium at maximum energy (center of mass) equal to 9 GeV/u. It includes new 6 Mev/u linac, 440 MeV/u booster, upgraded SC synchrotron Nuclotron and collider consisting of two SC rings, which provide average luminosity of 10²⁷cm^-2s^-1. General goal of the project is to start in the coming 5-7 years experimental study of hot and dense strongly interacting QCD matter and search for possible manifestation of signs of the mixed phase and critical endpoint in heavy ion collisions. The NICA and the Multi Purpose Detector (MPD) are proposed for these purposes. Accelerator complex NICA is being built on the experience and technological developments at the Nuclotron facility and incorporates new technological concepts. The new facility will allow also an effective acceleration of light ions to the Nuclotron maximum energy and an increase of intensity of polarized deuteron beams up to the level above 10¹⁰ particles/cycle. The scheme of the facility, its operation scenario and beam dynamics are presented in the report.

WEPP049	Advances on ELIC Design Studies	ion, optics, luminosity, collider	2632
	S. A. Bogacz, P. Chevtsov, Y. S. Derbenev, P. Evtushenko, M. Hutton, G. A. Krafft, R. Li, L. Merminga, J. Musson, B. C. Yunn, Y. Zhang Jefferson Lab, Newport News, Virginia J. Qiang LBNL, Berkeley, California H. K. Sayed Old Dominion University, Norfolk, Virginia
	An electron-ion collider of a center-of-mass energy up to 90 GeV at luminosity up to 10³⁵ cm^-2s^-1 with both beams highly polarized is essential for exploring the new QCD frontier of strong color fields in nuclear and precisely imaging the sea-quarks and gluons in the nucleon. A conceptual design of a ring-ring collider based on CEBAF (ELIC) with energies up to 9 GeV for electrons/positrons and up to 225 GeV for protons and 100 GeV/u for ions has been proposed to fulfill the science desire and to serve as the next step for CEBAF after the planned 12 GeV energy upgrade of the fixed target program. Here, we summarize recent design progress for the ELIC complex with four interaction points (IP); including interaction region optics with chromatic aberration compensation scheme and complete lattices for the Figure-8 collider rings. Further optimization of crab crossing angles at the IPs, simulations of beam-beam interactions and electron polarization in the Figure-8 ring and its matching at the IPs are also discussed.

WEPP051	QCD Explorer Based eA and γA Colliders	collider, ion, luminosity, linac	2635
	H. Karadeniz Turkish Atomic Energy Authority, Ankara E. Recepoglu SNRTC, Ankara S. Sultansoy TOBB ETU, Ankara
	TeV scale lepton-hadron and photon-hadron colliders are necessary both to clarify fundamental aspects of strong interactions and for adequate interpretation of the LHC data. Today, there are two realistic proposals for the post-HERA era, namely, QCD Explorer (QCD-E) and Large Hadron electron Collider (LHeC). Both QCD-E and LHeC can operate as eA colliders, whereas γp and γA options are unique for QCD-E. Another advantage of QCD-E is the possibility to increase the center of mass energy by lengthening of electron linac. In this presentation main parameters of the QCD-E nucleus options are discussed.

WEPP052	A Storage Ring Based Option for the LHeC	lepton, hadron, optics, proton	2638
	F. J. Willeke BNL, Upton, New York F. Bordry, H.-H. Braun, O. S. Brüning, H. Burkhardt, J. M. Jowett, T. P.R. Linnecar, K. H. Mess, S. Myers, J. A. Osborne, F. Zimmermann CERN, Geneva S. Chattopadhyay Cockcroft Institute, Warrington, Cheshire J. B. Dainton, M. Klein Liverpool University, Science Faculty, Liverpool B. J. Holzer DESY, Hamburg
	The LHeC aims at the generation of Hadron-Lepton collisions with center of mass energies in the TeV scale and luminosities of the order of 10³³ cm^-2 sec^-1 by taking advantage of the existing LHC 7 TeV proton ring and adding a high energy electron accelerator. This paper presents technical considerations and potential parameter choices for such a machine and outlines some of the challenges arising when an electron storage ring based option, constructed within the existing infrastructure of the LHC, is chosen.

WEPP061	A Position Monitor for the Aborted Beam in KEKB	kicker, septum, diagnostics, beam-losses	2659
	N. Iida, M. Kikuchi, T. Mimashi, K. Mori, M. Tejima KEK, Ibaraki
	The beams in the KEKB rings are aborted by abort kickers, Lambertson septums and dumps. First the beams are kicked by the abort kickers rapidly in the horizontal direction to outside the beam pipe and are bent slowly in the vertical direction. At the same time horizontal magnetic fields shake the beam to protect the abort window where the kicked beam passes and protect the window from heat by the high current beam. A beam position monitor is installed in front of the dump. We can get some informations of aborted beam by the monitor. In this paper a method for monitoring the beam in the high energy ring at KEKB is described.

WEPP075	Effects of the Cryogenic Operational Conditions on the Mechanical Stability of the FLASH Linear Accelerator Modules	quadrupole, cryogenics, linac, controls	2692
	R. Amirikas, A. Bertolini, J. Eschke, M. Lomperski DESY, Hamburg
	The Free electron LASer in Hamburg (FLASH) accelerating modules have been instrumented with vertical geophones on their corresponding quadrupoles and their vacuum vessels. The signals from these geophones are constantly monitored and the data are integrated into the control system of the accelerator. Therefore, vibration stability studies of a string of superconducting accelerating modules, in various cryogenic conditions, are now possible for the first time. The results of this experiment will be an important reference for both the European X-ray Free Electron Laser (XFEL) and the International Linear Collider (ILC) linear accelerators which are expected to take advantage from the separation between the feed lines of the 4.5 K shield and of the quadrupole, which will operate in a 2 K Helium-II bath.

WEPP077	The XFEL Laser Heater	laser, undulator, 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.

WEPP082	Recirculator SALO Project in NSC KIPT	injection, target, extraction, laser	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.

WEPP083	Development of an X-band Hybrid Dielectric-iris-loaded Accelerator	impedance, gun, longitudinal-dynamics, linac	2713
	X. D. He, S. Dong, G. Feng, Y. J. Pei, C.-F. Wu USTC/NSRL, Hefei, Anhui
	A compact x-band hybrid dielectric-iris-loaded travelling-wave linac with constant impendence structure has been designed. By adjusting the values of and the numbers of cells, the beam energy of 29 MeV, the capture efficiency about 50% and the energy spread about with the beam current being 70 mA and the electric gun voltage being 50KeV are obtained through longitudinal dynamics calculation. The length of accelerator tube is 1.12m . The maximum accelerating gradient is less than 45MV/m. By using electromagnetic code such as MAFIA, the attenuation per unit length of structure , the shunt impedance , the quality factor Q, the group velocity and the phase velocity are got by optimizing the dimensions of the cavities.

WEPP090	Accelerator Design for a 1/2 MW Electron Linac for Rare Isotope Beam Production	linac, klystron, target, gun	2728
	S. R. Koscielniak, F. Ames, I. V. Bylinskii, R. E. Laxdal, M. Marchetto, A. K. Mitra, I. Sekachev, V. A. Verzilov TRIUMF, Vancouver
	TRIUMF, in collaboration with university partners, proposes to construct a megawatt-class electron linear accelerator (linac) as a photo-fission driver for radioactive ion beam production (RIB) for nuclear astrophysics studies and materials science. The design strategy, including upgrade path, for this cost-effective facility is elaborated. The 50 MeV, 10 mA, c.w. linac is based on TESLA/ILC super-conducting radio-frequency (SRF) technology at 1.3 GHz and 2K; and consists of an electron gun, buncher and capture sections, followed by 10 MeV and 40 MeV cryomodules containing one and four 9-cell cavities, respectively. Preliminary results from PARMELA beam dynamics simulations are presented. C. W. operation leads to challenges of large cryogenic heat load, input coupler power handling and beam loss mitigation similar to those encountered in ERL-based light sources. Unlike those sources there is no need for high beam brilliance, and a triode thermionic gun modulated at 1.3 GHz is employed; nor are short bunches required, and so the HOM excitation is modest. Many of the major sub-system components have been identified and where possible existing designs will be adopted.

WEPP091	Injector Upgrade for the S-DALINAC	vacuum, linac, coupling, acceleration	2731
	T. Kuerzeder, A. Araz, M. Brunken, J. Conrad, R. Eichhorn, H.-D. Gräf, M. Hertling, F. Hug, M. Konrad, M. Platz, A. Richter, S. Sievers, T. Weilbach TU Darmstadt, Darmstadt W. Ackermann, W. F.O. Müller, B. Steiner, T. Weiland TEMF, Darmstadt J. D. Fuerst ANL, Argonne, Illinois
	Since 1991 the superconducting Darmstadt linear accelerator S-DALINAC provides an electron beam of up to 130 MeV for nuclear and astrophysical experiments. Currently its injector delivers beams of up to 10 MeV with a current of up to 60 μA. The upgrade aims to increase both parameters to 14 MeV and 150 μA in order to allow more demanding astrophysical experiments. Therefore, a modified cryostat module equipped with two new cavities is required. Due to an increase in RF power to 2 kW the old coaxial RF input couplers, being designed for a maximum power of 500 W, have to be replaced by new waveguide couplers. We review the design principles and report on the fabrication of the coupler and the whole module.

WEPP098	Efficient Traveling-wave Accelerating Structure for Linear Accelerators	coupling, bunching, acceleration, linac	2746
	V. M. Pirozhenko MRTI RAS, Moscow
	The shaped traveling-wave (STW) structure contains periodic structure of cavities with optimal shape and magnetic coupling operating in the forward traveling-wave mode. The structure combines the advantages of conventional standing-wave (SW) and traveling-wave (TW) structures. It ensures high efficiency of the use of radio-frequency (RF) power for the particle acceleration inherent in the SW structures. Also it gives a possibility to vary output energy of the particles by changing the beam loading and provides for good matching with RF generator without application of special matching devices that is inherent in the TW structures. The STW structure is well suited for compact variable-energy electron linear accelerators used for radiation technologies.

WEPP099	Results from Atomic Layer Deposition and Tunneling Spectroscopy for Superconducting RF Cavities	scattering, superconductivity, vacuum, coupling	2749
	J. Norem, J. W. Elam, M. J. Pellin ANL, Argonne, Illinois C. Z. Antoine CEA, Gif-sur-Yvette L. Cooley Fermilab, Batavia, Illinois J. F. Moore MassThink LLC, Naperville, IL Th. Proslier, J. Zasadzinski IIT, Chicago, Illinois
	Atomic Layer Deposition is a process that synthesizes materials in successive monolayers, at rates on the order of 1 micron/hour. We have been using this technique at Argonne as a possible way to improve both superconducting rf (SCRF) and normal rf structure performance. Initial experiments have led to a new model of high field Q-slope and new ways of controlling SCRF surfaces, as well as suggesting ways to significantly improve the operating gradients of both superconducting and normal structures. We have also been testing this technique in superconducting structures. Initial measurements show significant improvement over “cavity-grade” Nb samples.

WEPP105	First Operation Results of the Superconducting Photoinjector at ELBE	gun, cathode, laser, 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.

WEPP111	Modeling Breakdown in RF Cavities Using Particle-in-cell (PIC) codes	simulation, plasma, background, ion	2767
	S. Mahalingam, J. R. Cary, P. Stoltz, S. A. Veitzer Tech-X, Boulder, Colorado
	A main limitation on future accelerator projects is breakdown of metallic structures. We have developed computer models of the process of breakdown using Particle-In-Cell (PIC) codes which include: Fowler-Nordheim field emission due to large surface electric fields, impact ionization of neutral gas, ion-induced secondary electron emission, ion-induced sputtering of neutrals, the effects of applied magnetic fields, plasma radiation effects, and surface heating. Two computational tools have been used to self-consistently model the breakdown. These are OOPIC Pro, a 2-Dimensional serial electromagnetic code with cylindrical coordinates, and VORPAL, a 3-Dimensional massively parallel electromagnetic code with cartesian grids. We describe here the results of our numerical experiments including the effects of applied magnetic field strength and direction on the breakdown process, sensitivity of breakdown triggers on field emission parameters, and the potential to measure the onset of breakdown by examining impurity radiation. We show comparison with breakdown experiments performed at Fermilab and Argonne for copper structures being considered for a future muon collider project.

WEPP124	The Status of Turkish Accelerator Complex Project	factory, linac, positron, synchrotron	2788
	A. Aksoy, Ö. Karsli, B. Ketenoglu, O. Yavas Ankara University, Faculty of Engineering, Tandogan, Ankara A. K. Ciftci Ankara University, Faculty of Sciences, Tandogan/Ankara S. Sultansoy TOBB ETU, Ankara
	The Turkish Accelerator Complex (TAC) is proposed as a regional facility for accelerator based fundamental and applied research in 1997 with support of Turkish State Planning Organization (DPT). The feasibility and conceptual design phases of TAC proposal were completed in 2001 and 2005, respectively. Again with support of DPT, the technical design phase of TAC was started at the beginning of 2006. The complex will include 1 GeV electron linac and 3.56 GeV positron ring for linac on ring type electron-positron collider as a charm factory and a few GeV proton linac. Besides the particle factory, it is also planned to produce SASE FEL from electron linac and synchrotron radiation from positron ring. It is planed that the TDR of TAC Project will be completed in 2011 and the construction will be performed during following ten years .

WEPP127	ALaDyn: a High Accuracy Code for the Laser-plasma Interaction	simulation, plasma, laser, 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.

WEPP131	RF-breakdown Experiments at the CTF3 Two-beam Test-stand	ion, dipole, extraction, vacuum	2800
	M. Johnson, T. J.C. Ekelöf, R. J.M. Y. Ruber, V. G. Ziemann UU/ISV, Uppsala H.-H. Braun CERN, Geneva
	The Two-beam Test-stand (TBTS) in the CLIC Test Facility CTF3 offers unique possibilities to conduct RF-breakdown related experiments on the accelerating structures and the power extraction and transfer structures with beam. We report on the set-up of two such experiments, one for the measurement of the transverse kick and the other for the measurement of positive ion currents. The purpose of the transverse kick measurements is to determine the effects of a RF-breakdown event on the beam. Five BPMs in the TBTS will be used to study the trajectory of a pulse train after a RF-breakdown event, with important implications for the operation of CLIC. Ion currents ejected from accelerating structures during RF-breakdown events have already been observed at the 30 GHz test stand at the present test facility. Results and their implications for RF-breakdown physics are presented, as well as plans for similar measurements at the TBTS.

WEPP134	Ultra-short x-ray Radiation coming from a Laser Wakefield Accelerator	plasma, laser, 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, laser, 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	laser, 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	laser, radiation, 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, resonance, laser	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.

WEPP146	Generation of Electron Microbunches Trains with Adjustable Sub-picosecond Spacing for PWFA and FEL applications	plasma, laser, 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	gun, laser, 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.

WEPP151	Metallic Photonic Band Gap Accelerator Structure Experiments and Design	vacuum, damping, radiation, insertion	2841
	R. A. Marsh, M. A. Shapiro, R. J. Temkin MIT/PSFC, Cambridge, Massachusetts
	Damping wakefields is a critical issue in the next generation of high gradient accelerators. Photonic bandgap (PBG) structures have unique properties that offer significant wakefield damping. The goal of this work is to quantify the higher order mode (HOM) wakefield content of a constructed metallic PBG accelerator structure, in order to test the theory of wakefield excitation in these structures and to provide direction for future structure design. Experimental measurements of wakefields excited by an 18 MeV electron beam in a 6 cell, 17.14 GHz metallic PBG traveling wave accelerator structure are reported. Because the electron beam used to generate wakefields in the PBG structure is bunched at the 17.14 GHz rf frequency, all wakefields observed were at integer multiples of 17.14 GHz. Using diode detectors, radiation has been observed at the input and output coupler ports as well as through a quartz window in the surrounding vacuum vessel. Estimates of wakefield radiation, made using HFSS and basic wakefield theory, compare well with experiment.

WEPP154	Linac-LHC ep Collider Options	linac, proton, luminosity, emittance	2847
	F. Zimmermann, F. Bordry, H.-H. Braun, O. S. Brüning, H. Burkhardt, R. Garoby, T. P.R. Linnecar, K. H. Mess, J. A. Osborne, L. Rinolfi, D. Schulte, R. Tomas, J. Tuckmantel, A. de Roeck CERN, Geneva H. Aksakal N. U, Nigde S. Chattopadhyay Cockcroft Institute, Warrington, Cheshire A. K. Ciftci Ankara University, Faculty of Sciences, Tandogan/Ankara J. B. Dainton Liverpool University, Science Faculty, Liverpool A. Eide EPFL, Lausanne B. J. Holzer DESY, Hamburg M. Klein University of Liverpool, Liverpool S. Sultansoy TOBB ETU, Ankara A. Vivoli LAL, Orsay F. J. Willeke BNL, Upton, New York
	We describe various parameter scenarios for a ring-linac ep collider based on LHC and an independent s.c. electron linac. Luminosities of order 10³²/cm²/s can be achieved with a standard ILC-like linac, operated either in pulsed or cw mode, with acceptable beam power. Reaching much higher luminosities, up to 10³⁴/cm²/s and beyond, would require the use of two linacs and the implementation of energy recovery. Advantages and challenges of a ring-linac ep collider vis-a-vis an alternative ring-ring collider are discussed.

WEPP162	Beam Impact Studies on ILC Collimators	simulation, photon, controls, target	2865
	G. Ellwood STFC/RAL, Chilton, Didcot, Oxon J.-L. Fernandez-Hernando, J. K. Jones STFC/DL/ASTeC, Daresbury, Warrington, Cheshire M. Slater, N. K. Watson Birmingham University, Birmingham
	Spoilers in the ILC Beam Delivery System are required to survive without failure a minimum of 1-2 direct impacts of 250 GeV-500 GeV bunch of electrons or positrons, in addition to maintaining low geometric and resistive wall wake fields. Simulations were completed to determine the energy deposition of an ILC bunch to a set of different spoiler designs. These shower simulations were used as inputs to thermal and mechanical studies using ANSYS. This paper presents the results of testing carried out at the Accelerator Test Facility at KEK used to validate the simulations. Results from the first phase of testing, in which electron bunches of varying charge were incident on TI-6Al-4V foils, are presented and compared with simulations.

WEPP166	Comparison of Collimator Wakefields Formulae	dipole, impedance, quadrupole, vacuum	2877
	A. M. Toader, R. J. Barlow UMAN, Manchester
	There is an extensive literature on transverse wakefield kick factors in collimators. We present a compendium of the formulae and discuss their agreement and disagreement with each other and with experimental results.

THYG02	Results from the CLIC Test Facility CTF3 and Update on the CLIC Design	linac, acceleration, luminosity, beam-loading	2912
	G. Geschonke CERN, Geneva
	The CLIC Test Facility CTF3 is being built and commissioned in stages. Up to now the facility consists of an electron linac, a magnetic chicane for changing bunch length, the Delay Loop and the Combiner Ring. Recent experience and commissioning results will be presented together with plans for the next steps which should lead to feasibility demonstration of CLIC technology by the year 2010. The CLIC design has been reviewed in detail. The resulting changes in parameters will be presented.
	Slides

THXM02	Development of the KEK-B Superconducting Crab Cavity	superconductivity, positron, cryogenics, acceleration	2927
	K. Hosoyama, K. Akai, K. Ebihara, T. Furuya, K. Hara, T. Honma, A. Kabe, Y. Kojima, S. Mitsunobu, Y. Morita, H. Nakai, K. Nakanishi, M. Ono, Y. Yamamoto KEK, Ibaraki H. Hara, K. Okubo, K. Sennyu, T. Yanagisawa MHI, Kobe
	The development of the KEK-B superconducting crab cavity, including the design, production, tests and latest parameter performances should be described in this talk.
	Slides

THYM03	Advanced Computing Tools and Models for Accelerator Physics	simulation, space-charge, linac, collider	2947
	R. D. Ryne LBNL, Berkeley, California
	The design of the next generation of accelerators will require a new level of simulation capability to perform high resolution, multi-physics modelling of beam dynamics phenomena and to design complex 3D electromagnetic structures. Thanks to the availability of computational resources that will soon reach the petascale, we will be able to perform simulations involving unprecedented size, complexity, and physical realism. This paper will review the state-of-the-art in scientific computing for accelerator physics.
	Slides

THPC004	Chromatic and Wakefield Effects in PSI-XFEL Linac	linac, emittance, quadrupole, injection	2978
	B. Grigoryan, G. A. Amatuni, V. M. Tsakanov CANDLE, Yerevan R. J. Bakker, Y. Kim, M. Pedrozzi, J.-Y. Raguin PSI, Villigen
	Detailed knowledge about the wakefield and chromatic effects on electron beam emittance is an important issue to preserve the natural emittance of the beam in linear accelerators for FEL. The study of these two effects for beam and accelerator components imperfections in PSI-XFEL S-Band linear accelerator is presented. Emittance dilution caused by the beam coherent oscillations, accelerating section and quadrupole misalignments is analysed. The residual chromatic emittance dilution of the corrected trajectory is evaluated.

THPC010	Trajectory Correction in the Fermi@Elettra Linac	linac, quadrupole, simulation, lattice	2993
	S. Di Mitri ELETTRA, Basovizza, Trieste A. Zholents LBNL, Berkeley, California
	The effect of the static magnetic field errors and misalignment of the magnetic elements and linac modules on the beam trajectory in the Fermi@elettra linac [1] has been studied. Analytical description has been used to guide simulations of the trajectory correction using three different techniques. A control over the residual R56 transfer matrix element along the linac lattice has been applied. The importance of the linac structural transverse wake field for a reliable prediction of the bunch centroid dynamics has been demonstrated. Transverse deviations of bunch slices along the electron bunch induced by the wake fields have been calculated. [1] S. Di Mitri, ST/M–07/01 (2007)

THPC012	Longitudinal Beam Dynamics Studies for the FERMI@ELETTRA Linac	linac, klystron, emittance, space-charge	2999
	O. Ferrando, G. D'Auria ELETTRA, Basovizza, Trieste
	FERMI is a single-pass FEL project under construction at Sincrotrone Trieste Laboratory. It will be driven by the present warm S-band linac, upgraded by the addition of seven accelerating sections to bring its working energy up to 1.2 GeV. The goal of the project is to have an X-ray user facility covering the wavelength region between 100 -10 nm. The stringent constraints on the electron beam parameters required by FERMI, such as emittance, pulse to pulse energy and current stabilities, and time of arrival of the bunch at the input of the undulator chain, impose very stringent requirements on the parameters and operating conditions of the linac accelerating sections. To address the problem, i.e. evaluating the operating conditions of the machine and the flexibility of the adopted layout, beam dynamics studies with the LiTrack code have been performed. Here the results of different linac settings as well as the allowed variations in terms of RF phase and amplitude of the accelerating field are presented and discussed.

THPC014	Investigation of Possible CSR Induced Energy Spread Effects with the A0 Photoinjector Bunch Compressor	simulation, radiation, emittance, synchrotron	3005
	R. P. Fliller, H. T. Edwards, G. M. Kazakevich, J. Ruan, R. Thurman-Keup Fermilab, Batavia, Illinois T. W. Koeth Rutgers University, The State University of New Jersey, Piscataway, New Jersey
	The bunch compressor of the A0 Photoinjector at Fermilab was removed this past spring to install a transverse to longitudinal emittance exchange experiment. Prior to its removal questions arose about the possibility of observing the effects of Coherent Synchrotron Radiation on the compressed beam. The energy spread of the beam with and without compression was measured to observe any changes. Various beam charges were used to look for square law effects associated with CSR. No direct observation of CSR was attempted because the design of the vacuum chamber did not allow it. In this paper we report the results of these experiments and comparison with simulations using ASTRA and CSRTrack. The results are compared with analytical approximations. The implications for the ongoing transverse to longitudinal emittance exchange experiment are discussed.

THPC018	Beam Dynamics Issues in the CLIC Long Transfer Line	ion, injection, emittance, positron	3017
	J. B. Jeanneret, E. Adli, A. Latina, G. Rumolo, D. Schulte, R. Tomas CERN, Geneva
	Both the main beam and the drive beam of the CLIC project must be transported from the central production site to the head of the main linacs over more than twenty kilometres. Over such distances chromatic aberrations are substantial. With long distances and large beam currents, detuning and instabilities associated to ion production and multi-bunch resistive wall effects must also be considered. These effects are quantified and simulated. Based on these results, we propose a baseline design for these two lines.

THPC020	Emittance Exchange at the Fermilab A0 Photoinjector	emittance, optics, diagnostics, controls	3020
	T. W. Koeth Rutgers University, The State University of New Jersey, Piscataway, New Jersey L. Bellantoni, H. T. Edwards, R. P. Fliller, A. H. Lumpkin, J. Ruan Fermilab, Batavia, Illinois
	A transverse to longitudinal emittance exchange experiment is underway at the A0 Photoinjector at Fermilab. Our scheme employs a TM110 deflecting mode RF cavity between two magnetic doglegs proposed by Kim et. al. The beamline has been installed, characterization of the beamline is complete and data taking has begun. In this paper we report on efforts to date to observe the transverse to longitudinal emittance exchange. Measurements will be compared to analytical predictions and simulations.

THPC027	Pulsed RF Accelerator of Electrons with Beam Recirculation	linac, simulation, acceleration, dipole	3038
	V. V. Mytrochenko, M. I. Ayzatskiy, P. Gladkikh, V. A. Kushnir, A. Opanasenko, A. Y. Zelinsky NSC/KIPT, Kharkov S. Chemerisov, D. Ehst ANL, Argonne, Illinois
	We discuss the project of upgrading existent 20 MeV L-band electron linac at Argonne National Laboratory aimed at electron energy increasing. It is shown that the proposed beam recirculation will provide on the accelerator output an electron beam with a pulse current 0.5 A and energy of particles 45 MeV. Problems of stability of recirculating beam are discussed.

THPC038	Beam Dynamic Simulations of the New Polarized Electron Injector of the S-DALINAC	simulation, gun, emittance, linac	3062
	B. Steiner, W. Ackermann, S. S. Franke, W. F.O. Müller, T. Weiland TEMF, Darmstadt R. Barday, C. Eckardt, R. Eichhorn, J. Enders, C. Hessler, Y. Poltoratska, A. Richter, M. Roth TU Darmstadt, Darmstadt
	Aiming at an extension of the experimental possibilities at the Superconducting Darmstadt electron linear accelerator S-DALINAC, a polarized gun is going to be constructed at the moment. The new injector will be able to supply polarized electrons with kinetic energy in the 100 keV range and should add to the present unpolarized thermionic 250 keV source. The design requirements include a polarization degree of at least 80%, a mean current intensity of 60 μA and a 3 GHz cw time structure. The gun part is simulated in CST MAFIA whereas subsequent beam dynamics simulations are performed in V-Code. Initial conditions for the V-Code’s moment approach are extracted from the CST MAFIA simulations. The injector consists of short triplets, an alpha magnet, a Wien filter, a Mott polarimeter, a chopper/prebuncher system and beam diagnostic elements. For the simulations, the 3D electromagnetic fields of the beam line elements are used by means of a Taylor series expansion of variable order. All components except the chopper and a collimator is represented in the simulations. Recent beam dynamic results will be presented.

THPC042	Uncoupled Achromatic Tilted S-bend	quadrupole, dipole, controls, coupling	3071
	N. Tsoupas, A. Kayran, V. Litvinenko, W. W. MacKay BNL, Upton, Long Island, New York
	A particular section of one of the electron beam transport lines, to be used in the e-cooling project* of the Relativistic Heavy Ion Collider (RHIC), is constrained to bend the beam simultaneously in both the horizontal and vertically planes and also be achromatic in both planes. The simultaneous horizontal and vertical achromatic bend is accomplished by rotating, about the longitudinal axis of the beam, the dipole and quadrupole elements of this section of the line. However such a rotation of the magnetic elements may couple the transported beam through the first order beam transfer matrix (linear coupling). In this paper we investigate for a sufficient condition, that the first order transport matrix (R-matrix) can satisfy, under which such a section of a beam transfer line is both achromatic and also constrains the beam at the exit of the line to emerge linearly uncoupled. We also provide a complete solution for the beam optics, of this part of the beam transfer line, which satisfies achromaticity and no first order beam coupling. *htpp://www.bnl.gov/cad/eRhic/Documents/AD_Position_Paper_2007.pdf

THPC062	Multi-Particle Weak-Strong Simulations of RHIC Head-on Beam-Beam Compensation	emittance, simulation, proton, dynamic-aperture	3125
	Y. Luo, N. P. Abreu, W. Fischer, G. Robert-Demolaize BNL, Upton, Long Island, New York
	An electron beam has been proposed in the Relativistic Heavy Ion Collider (RHIC) to compensate beam-beam effects in polarized proton collisions. This electron beam will collide head-on with the proton beam. Using the weak-strong beam-beam interaction model, we have carried out six-dimensional multiparticle simulations to investigate the effects of head-on beam-beam compensation. Beam lifetime, transverse emittances, and luminosity are calculated for cases with and without beam-beam compensation for up to 10 million turns. The migrations of particles between different actions and the beam spectrum are also calculated.

THPC069	Impact of Magnet Misalignment in an ERL for Electron Cooling in RHIC	emittance, dipole, linac, space-charge	3146
	V. H. Ranjbar, D. T. Abell, K. Paul Tech-X, Boulder, Colorado I. Ben-Zvi, J. Kewisch BNL, Upton, Long Island, New York R. D. Ryne LBNL, Berkeley, California
	The MaryLie/IMPACT code was recently upgraded to include magnet errors. We have used the code to assess the sensitivity of final emittance of an ERL injector for the proposed RHIC electron cooler to up-stream magnetic element misalignments. This calculation will help determine the error tolerance for the construction of the ERL.

THPC070	Symmetry Restoration of the SPring-8 Storage Ring by Counter-sextupole Magnets	sextupole, dynamic-aperture, lattice, betatron	3149
	K. Soutome, S. Daté, T. Fujita, K. Fukami, C. Mitsuda, A. Mochihashi, H. Ohkuma, M. Oishi, S. Sasaki, J. Schimizu, Y. Shimosaki, M. Shoji, M. Takao, K. Tsumaki, H. Yonehara, C. Zhang JASRI/SPring-8, Hyogo-ken S. Matsui, H. Takebe, H. Tanaka RIKEN/SPring-8, Hyogo
	In the SPring-8 storage ring there are four magnet-free long straight sections of about 30m. These were realized in 2000 by locally rearranging quadrupole and sextupole magnets. In modifying the optics we took care of the periodicity of cell structure, especially of sextupole field distribution along the ring. To keep the periodicity high and hence the dynamic aperture large, we adopted a scheme in which "betatron phase matching" and "local chromaticity correction" are combined. In this scheme the dynamic aperture for on-momentum electrons is kept by the phase matching and that for off-momentum electrons is enlarged by the local chromaticity correction with weak sextupoles (SL). After modifying the lattice, we tried to recover the symmetry of the ring further and found that a harmful effect of nonlinear kick due to SL can be minimized by additional "counter-sextupole magnets" placed 180 degrees apart in horizontal betatron phase from SL. We installed such counter-sextupoles in every long straight sections and confirmed that the aperture was improved. In the paper we discuss these topics showing experimental data of injection efficiency, momentum acceptance, etc.

THPC076	Closed Orbit Correction and Sextupole Compensation Schemes for Normal-conducting HESR	sextupole, closed-orbit, dipole, lattice	3161
	D. M. Welsch, A. Lehrach, B. Lorentz, R. Maier, D. Prasuhn, R. Tölle FZJ, Jülich
	The High Energy Storage Ring (HESR) will be part of the future Facility for Antiproton and Ion Research (FAIR) located at GSI in Darmstadt, Germany. The HESR will be operated with antiprotons in the momentum range from 1.5 to 15 GeV/c, which makes a long beam life time and a minimum of particle losses crucial. This and the demanding requirements of the PANDA experiment lead to the necessity of a good orbit correction and an effective multipole compensation. We developed a closed orbit correction scheme and tested it with Monte Carlo simulations. We assigned different sets of angular and spatial errors to all elements (magnets, bpms, etc.) within the lattice of the HESR. For correction we applied the orbit response matrix method. We carried out investigations concerning higher-order multipoles and created a scheme for chromaticity correction and compensation of arising resonances utilising analytic formulae and dynamic aperture calculations. In this presentation we give an overview of the correction and compensation schemes and of the corresponding results.

THPC077	Transportation Channel with Uniform Electron Distribution for the Kharkov Neutron Source based on Subcritical Assembly Driven with Linear Accelerator	target, octupole, focusing, quadrupole	3164
	A. Y. Zelinsky, I. M. Karnaukhov NSC/KIPT, Kharkov
	Electron beam transportation channel from linear accelerator to the neutron target of NSC KIPT neutron source should provide uniform distribution of electrons on target surface to prevent overheating of the target and reduce thermal stress. In the presented channel the method of uniform beam distribution formation with linear focusing elements and nonlinear focusing elements (octupole magnets) we used. Linear focusing elements were used to provide particle transportation through the channel without losses and to form required beam sizes at the target. Nonlinear focusing elements were used to modulate transverse velocity of peripheral particles. As a result the uniform electron beam of rectangular shape can be formed at the target. In the report the main principles of transportation channel design and results of calculations for NSC KIPT neutron source based on subcritical assembly driven by electron accelerator are presented. Lattice and parameters of focusing elements are presented. Calculation results show that proposed transportation channel lattice can provide uniform beam of rectangular shape with sizes 66x66 mm.

THPC078	Injection Scheme of X-rays Source NESTOR	injection, storage-ring, quadrupole, simulation	3167
	A. Y. Zelinsky, I. M. Karnaukhov, A. Mytsykov, V. L. Skirda NSC/KIPT, Kharkov
	In the paper the injection scheme of the X-ray source NESTOR based on the compact storage ring and Compton scattering is described. It is supposed to inject electron beam through fringe fields of a bending magnet. For final beam deflection electrical inflector on the running wave will be used. The layout of the injection scheme and elements characteristics are presented. The results of simulations of electron beam motion through 3-d fields of electro-magnetic devices of the injection channel are presented.

THPC085	VORPAL Simulations Relevant to Coherent Electron Cooling	ion, plasma, simulation, hadron	3185
	G. I. Bell, D. L. Bruhwiler, A. V. Sobol Tech-X, Boulder, Colorado I. Ben-Zvi, V. Litvinenko BNL, Upton, Long Island, New York Y. S. Derbenev Jefferson Lab, Newport News, Virginia
	Coherent electron cooling (CEC)* combines the best features of electron cooling and stochastic cooling, via free-electron laser technology, to offer the possibility of cooling high-energy hadron beams with order-of-magnitude shorter cooling times. Many technical difficulties must be resolved via full-scale 3D simulations, before the CEC concept can be validated experimentally. VORPAL is the ideal code for simulating the “modulator” and “kicker” regions, where the electron and hadron beams will co-propagate as in a conventional electron cooling section. Unlike previous VORPAL simulations* of electron cooling physics, where dynamical friction on the ions was the key metric, it is the details of the electron density wake driven by each ion in the modulator section that must be understood, followed by strong amplification in the FEL. We present some initial simulation results. In particular, we compare the semi-analytic binary collision model with electrostatic particle-in-cell (PIC). Ya. S. Derbenev, COOL ’07 Proc. (2007). V. N. Litvinenko and Ya. S. Derbenev, FEL ’07 Proc. (2007). **A. V. Fedotov et al. Phys. Rev. ST/AB 9, 074401 (2006).

THPC087	Electron Traps and Advanced Turbulence Diagnostic	laser, 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.

THPC089	Electron-cloud Intrabunch Density Modulation	dipole, simulation, proton, resonance	3197
	G. Franchetti GSI, Darmstadt F. Zimmermann CERN, Geneva
	During the passage of a proton bunch through an electron cloud a complicated electron density modulation arises, with characteristic ring and stripe patterns of high density regions that move radially outward along the bunch. We present simulation results as well as a simple analytical model to reveal the morphology and main features of this phenomenon as well as its dependence on key parameters like bunch length, beam size, and bunch charge.

THPC091	Experimental Study of an Intense Relativistic Helical Electron Beam Formed with Interception of the Electrons Reflected from the Magnetic Mirror	gun, cathode, space-charge, radiation	3200
	E. V. Ilyakov, I. S. Kulagin, S. V. Kuzikov, A. S. Shevchenko IAP/RAS, Nizhny Novgorod V. N. Manuilov NNGU, Nizhny Novgorod
	A new method of formation of pulsed intense relativistic helical electron beams (HEBs) for gyroresonant devices has been presented. The method is aimed at the increase of pitch-factor and the reduction of HEB velocity spread and is intended for use in the formation systems of laminar HEBs characterized by low influence of space charge on their parameters. The method is based on the operation of a special diaphragm located at one of minima of trajectories at the beginning of the transportation channel. The diaphragm diameter is chosen so that the electrons with the lowest oscillatory velocities cannot bend round the diaphragm and settle on it. The rest electrons pass by moving in the increasing magnetic field. Then, the electrons with the greatest oscillatory velocities are adiabatically reflected from the magnetic mirror between the electron gun and the transportation channel and settle on the back of the same diaphragm. Reduction of space charge of the reflected electrons has led to the increase of HEB pitch-factor (HEBs have been formed with the record of pitch-factors exceeding 2), while the accumulation of space charge worsens the HEB provoking modulation of formed HEB current.

THPC104	Optical Diagnostic on Gabor Plasma Lenses	plasma, ion, emittance, simulation	3221
	K. Schulte, M. Droba, O. Meusel, U. Ratzinger IAP, Frankfurt am Main
	Gabor lenses have been built and successfully been used for the focussing of particle beams. In the case of a positive ion beam the space charge of the confined electron cloud may cause an over compensation of the ion beam space charge force and consequently focus the beam. The nonneutral plasma (NNP) is influenced by the external fields and its current state can be determined by the beam emittance growth. Experiments using a high field Gabor lens have shown a correlation between the thermalization of the enclosed electron cloud and the focussing quality. A three segmented Gabor lens was constructed recently for a more detailed investigation of the plasma parameters as a function of the external fields. The commissioning of the lens has been finished successfully and the light emitted by the interaction between the electron cloud and the residual gas has been observed. In a next step the experiments will concentrate on the spectral analyses of the emitted light to evaluate the temperature and density distribution of the confined NNP. Experimental results will be presented in comparison with numerical simulation.

THPC105	Self-consistent Transverse Dynamics and Interbunch Energy Exchange in Dielectric Loaded Wakefield Accelerating Structures	focusing, acceleration, transverse-dynamics, vacuum	3224
	I. L. Sheynman LETI, Saint-Petersburg A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio
	The self-consistent transverse dynamics of high current relativistic electron beams used for generating wakefields in dielectric loaded structures is investigated. The primary application of this work is to multi-bunch wakefield acceleration. The maximum distance the high current beam can travel through the structure in the absence of focusing without experiencing beam breakup and the energy transferred to the accelerated electron bunch will be presented. We consider both ramped and uniform charge distributions in the sequence of high current drive bunches. The ramped drive charge distribution is compared to the case of a uniform charge distribution in terms of the requirements for the beam focusing system and the effectiveness of the energy transfer to the accelerated electron bunch.

THPC107	Beam Dynamical Issues of the KEK All-ion Accelerator	ion, vacuum, injection, acceleration	3227
	K. Takayama, T. Adachi, E. Nakamura, H. Someya KEK, Ibaraki
	R&D works to realize an all-ion accelerator (AIA)* capable of accelerating all species of ions with any possible charge state, based on the induction synchrotron concept, which was demonstrated using the KEK 12 GeV-PS in 2006*, are going on at KEK. The KEK AIA, which is a modification of the existing KEK 500 MeV Booster Ring of a rapid cycle synchrotron, may be an injector-free accelerator. An ion beam from the high-voltage terminal of 200 kV is directly injected into the accelerator ring. Several key issues associated with the low energy injection must be addressed. Space-charge limited current due to a small relativistic b and a short life-time due to scattering with the residual molecules and eddy-current induced magnetic fields associated with guide-fields ramping from a low field level are among them. Careful considerations on them suggest that there are significant constrains on the operational performance and gives achievable beam parameters assuming the present parameters of the KEK AIA. K. Takayama, Y. Arakida, T. Iwashita, Y. S himosaki, T. Dixit, K. Torikai, J. of Appl. Phys. 101, 063304 (2007). **K. Takayama et al., Phys. Rev. Lett. 98, 054801 (2007).

THPC108	Observation of Bound States of Particles in the Storage Ring	storage-ring, synchrotron, radiation, vacuum	3230
	A. S. Tarasenko, I. S. Guk NSC/KIPT, Kharkov
	The deviation of n-particle state lifetime from the law T1/n, where T1 is a mean lifetime of one particle, in the storage ring was experimentally observed. Authors relate this deviation to interaction between the particles, conditioned by the fields directed in passive resonant devices of vacuum chamber of the storage ring. Depending on type of connection of the beam with passive resonant device, the interaction can be repulsive or attracting. The binding energy of a pair of particles for a case of their effective attraction is calculated.

THPC118	Performance and Future Developments of the Diamond Fast Orbit Feedback System	feedback, controls, storage-ring, target	3257
	M. T. Heron, M. G. Abbott, J. A. Dobbing, G. Rehm, J. Rowland, I. Uzun Diamond, Oxfordshire S. Duncan University of Oxford, Oxford
	The electron beam in the Diamond Synchrotron Light Source is stabilised in two planes using a Global Beam Orbit Feedback system. This feedback system takes the beam position from 168 Libera electron beam position monitors, for both planes, and calculates offsets to 336 corrector power supplies at a rate ~10kHz. The design and implementation will be summarised, and system performance and first operational experience presented. Current and potential future developments of the system will be considered.

THPC129	Coupling Correction in NSLS X-ray Ring	quadrupole, coupling, storage-ring, insertion	3290
	M. G. Fedurin, I. Pinayev BNL, Upton, Long Island, New York
	In this paper we describe MATLAB script for reduction of the transverse coupling in the NSLS X-ray storage ring. The algorithm is based on varying strength of the skew quadrupoles and observation of the vertical beam size. The details of the iterative procedure are also discussed.

THPC139	Properties of X-ray Beam Position Monitors at the Swiss Light Source	feedback, photon, vacuum, controls	3312
	T. Wehrli, M. Böge, J. Krempasky, E. D. van Garderen PSI, Villigen
	Tungsten blade type X-ray beam position monitors (X-BPMs) are widely used at the SLS to stabilize the photon beam position at the the micron level. Various slow (~0.5 Hz) photon beam position feedbacks (SPBPFs) being an integral part of the global orbit feedback system have been in operation for several years. They are solely based on one X-BPM reading assuming that the photon beam movement is dominated by angle changes of the electron beam. This paper reports on the operation of the first SPBPF using two X-BPMs. This allows the separation of positional and angular variations of the electron beam, which is of special importance for the recently commissioned PolLux dipole beamline, as it is mostly sensitive to position changes. Correlations between the electron beam movement and the X-BPM readings are extensively analyzed in order to disentangle systematic errors of the position determination and real orbit motion. Methods are presented on how to recognize and correct or even avoid large systematic errors of the X-BPMs. With this knowledge, the demanding requirements on X-BPM accuracy in case of a SPBPF utilizing two X-BPMs could be fulfilled for the first time at the SLS.

THPC143	A Wide Range Electrons, Photons, Neutrons Beam Facility	linac, photon, positron, diagnostics	3321
	B. Buonomo, G. Mazzitelli, F. Murtas, L. Quintieri INFN/LNF, Frascati (Roma) P. Valente INFN-Roma, Roma
	The DAΦNE Beam Test Facility is in operation since the 2003 and has been continuously improved and upgraded in order to take into account the many different requests coming from the high energy and accelerator community. The facility was initially optimized to produce single electron and positron in the 25-750 MeV energy rage, manly for high energy detector calibration and testing; it can now provide beam in a wider range of intensity, up to 10¹⁰ electrons/pulse, typically needed for accelerator diagnostic tests. In the last two years the facility has also been modified in order to produce tagged photons, and the possibility to deliver tagged neutrons in the MeV energy range is under study. The main results obtained, the performance and the most significant characteristics of the facility diagnostics and operation are presented, as well as the users experience collected during these years of operation.

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

THPC148	Interlock – the Machine Protection Function of Libera Brilliance	instrumentation, brilliance, pick-up, controls	3336
	P. L. Lemut, T. Karcnik, A. Kosicek Instrumentation Technologies, Solkan
	The basic task of Libera Brilliance is electron beam position measurement. A secondary, but no less important, task is machine protection. Libera Brilliance activates Interlock output when the beam position is outside predefined limits. The Interlock subsystem also activates when the analog-to-digital converters (AD) are saturated and the beam position is only virtually centered. AD converter saturation is detected in the multiplexed fast peak detectors using AD converter rate data. The Interlock is designed for fail-safe operation. Within the FPGA window, a comparator function is performed on the Fast Acquisition position data delivered at a 10 kHz rate. Comparison is done separately for X and Y positions. Limits and operation mode are settable through the CSPI library. To avoid manual resetting of the Interlock, logic output is designed as a monostable cell. The described circuitry has been successfully implemented and tested in both laboratory and accelerator environments.

THPC152	Electro-optic Bunch Arrival Time Measurement at FLASH	laser, 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.

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

THPC158	Measurement and Stabilization of the Bunch Arrival Time at FLASH	feedback, laser, controls, 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	laser, controls, diagnostics, polarization	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.

THPP001	Development of FFAG Electron Accelerator	septum, extraction, acceleration, induction	3372
	T. Baba, M. Takahashi, Y. Yuasa NHVC, Kyoto Y. Mori KURRI, Osaka
	Electron Beam (EB) Accelerators have been used in the many industrial fields to improve physical properties of the material. Examples are wire and cable industries, rubber tire industries, foam industries, etc. EB is also widely used for medical device sterilization as a popular tool. High power, high reliability, compactness and low cost are key requirements to get popularity of the technology and to open up its application fields. The paper will present FFAG electron accelerator to meet these requirements that NHV Corporation recently developed and some of the interesting performance such as beam extraction efficiency will be discussed in the paper.

THPP002	EMMA RF Cavity Design and Prototype Testing at Daresbury	impedance, acceleration, vacuum, kicker	3374
	C. D. Beard, P. A. Corlett, D. M. Dykes, P. Goudket, C. Hill, P. A. McIntosh, A. J. Moss, J. F. Orrett, J. H.P. Rogers, A. E. Wheelhouse, E. Wooldridge STFC/DL/ASTeC, Daresbury, Warrington, Cheshire N. Bliss STFC/DL, Daresbury, Warrington, Cheshire A. E. Bogle, T. L. Grimm, A. A. Kolka Niowave, Inc., Lansing, Michigan
	At PAC’07 we discussed the design of a prototype cavity to be used on EMMA. EMMA is a prototype non-scalling FFAG. It will contain 19 RF cavities operating at 1.3 GHz with a baseline accelerating voltage of 120 kV. A prototype cavity has been manufactured by Niowave, Inc. and we will present a discussion of its RF and mechanical design. This cavity was put through low power tests, to determine frequency, tuning range, shunt impedance and Q of the cavity; and high power tests, to confirm power handling ability, when it arrived at Daresbury Laboratory this spring. The results of these tests were compared to the simulations and a bead pull was carried out to obtain the field profile. The cavities for EMMA are likely to be powered by IOTs, these will be used for the high power tests, which will demonstrate cavity operation to the required maximum of 180 kV. E. Wooldridge et al. "RF Cavity Development for FFAG Application on ERLP at Daresbury," Proceedings of PAC’07, Albuquerque, NM (2007).

THPP046	Applicability of Stochastic Cooling in Small Electrostatic Storage Rings	pick-up, ion, storage-ring, kicker	3464
	H. Danared MSL, Stockholm
	Several small electrostatic storage rings have been built or are being built for experiments in atomic and molecular physics. One example is the DESIREE double electrostatic storage ring* under construction at the Manne Siegbahn Laboratory. At the KEK electrostatic storage ring, electron cooling of 20 keV protons has been demostrated*. For heavy molecules, however, including bio-molecules, electron-cooling times are unrealistically long because of the low ion velocity and the correspondingly low electron energy which results in very small electron currents. For this reason, electron cooling is not foreseen for DESIREE. The rates of stochastic cooling, on the other hand, are at first glance unrelated to beam energy. Furthermore, the low particle numbers expected for many heavy molecules seem to make stochastic cooling attractive, theoretical rates being inversely proportional to particle numbers. In this paper, the rates of stochastic cooling for slow heavy particles are investigated with respect to, mainly, the bandwidths and signal strengths that can be expected at the low particle velocieties that are of interest at, e.g., DESIREE, and some numerical examples are presented. P. Löfgren et al., these proceedings ** E. Syresin, K. Noda and T. Tanabe, Proc. EPAC 2004, p. 162

THPP047	Prototype of the High Voltage Section for the 2 MeV Electron Cooler at COSY	feedback, acceleration, controls, power-supply	3467
	J. Dietrich FZJ, Jülich M. I. Bryzgunov, A. D. Goncharov, V. V. Parkhomchuk, V. B. Reva, D. N. Skorobogatov BINP SB RAS, Novosibirsk
	The design, construction and installation of a 2 MeV electron cooling system for COSY-Juelich is proposed to further boost the luminosity even with strong heating effects of high-density internal targets. In addition the 2 MeV electron cooler for COSY is intended to test some new features of the high energy electron cooler for HESR at FAIR/GSI. The design of the 2 MeV electron cooler will be accomplished in cooperation with the Budker Institute of Nuclear Physics in Novosibirsk, Russia. The design and first experiments of a new developed prototype of the high voltage section, consisting of a gas turbine, magnetic coils and high voltage generator with electronics is reported.

THPP048	Experimental Demonstration of Longitudinal Ion Beam Accumulation with Electron Cooling	injection, kicker, ion, bunching	3470
	C. Dimopoulou, B. Franzke, T. Katayama, F. Nolden, G. Schreiber, M. Steck GSI, Darmstadt D. Möhl CERN, Geneva
	Recently, two longitudinal beam compression schemes have been successfully tested in the Experimental Storage Ring (ESR) at GSI with a beam of bare Ar ions at 65 MeV/u injected from the ion synchrotron SIS18. The first employs Barrier Bucket pulses, the second makes use of multiple injections around the unstable fixed point of a sinusoidal RF bucket at h=1. In both cases continuous electron cooling maintains the stack and merges it with the freshly injected bunch . Using the beam diagnostic devices in the ring both stacking processes were demonstrated under the same conditions. The dependence of the accumulation performance on the available rf potential, the electron cooling strength as well as on the synchronization conditions between injection kicker pulse and rf wave was investigated. These experimental results provide the proof of principle for the planned fast stacking of Rare Isotope Beams aiming at high luminosities in the New Experimental Storage Ring * of the FAIR project **. C. Dimopoulou et al., JACoW Proceedings of COOL07, Bad Kreuznach,2007. C. Dimopoulou et al., PRST-AB 10 (2007) 020101. * FAIR Baseline Technical Report,www.gsi.de/fair/.

THPP049	Status of Electron Cooler Design for HESR	vacuum, antiproton, diagnostics, target	3473
	B. Gålnander, T. Bergmark, S. Johnson, T. Johnson, T. Lofnes, G. Norman, T. Peterson, K. Rathsman, D. Reistad TSL, Uppsala H. Danared MSL, Stockholm
	The HESR-ring of the future FAIR-facility at GSI will include both electron cooling and stochastic cooling in order to achieve the demanding beam parameters required by the PANDA experiment. The high-energy electron cooler will cool antiprotons in the energy range 0.8 GeV to 8 GeV. The design is based on an electrostatic accelerator and shall not exclude a further upgrade to the full energy of HESR, 14.1 GeV. The paper will discuss prototype tests of critical components and recent development in the design including the high-voltage tank, electron gun and collector, magnet system, electron beam diagnostics and the magnetic field measuring system.

THPP050	Recent Status of Laser Cooling for Mg Realized at S-LSR	laser, ion, coupling, synchrotron	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.

THPP052	Electron Cooling Force Calculations for HESR	ion, plasma, antiproton, beam-transport	3482
	K. Rathsman, B. Gålnander, D. Reistad TSL, Uppsala H. Danared MSL, Stockholm
	The High energy storage ring HESR at FAIR is being realized by a consortium consisting of Forschungszentrum Jülich, GSI Darmstadt and Uppsala University. An important feature of this new facility is the combination of phase-space cooled beams and dense internal targets. Charmonium spectroscopy, which is one of the main items in the experimental program, requires antiproton momentum up to 8.9 GeV/c with a resolution of dp/p=0.00001. This can only be achived with electron cooling. The electron cooler proposed for HESR allows beam cooling between 1.5 GeV/c and 8.9 GeV/c. Along the 24 m interaction section beween electrons and antiprotons, the electrons are guided by a solenoid field of 0.2 T with a field straightness of 0.00001 radians rms. To predict the final momentum resolution of the antiproton beam in HESR, electron cooling force calculations, simulations of electron cooling and comparison to experimental data are needed. This paper focuses on the force calculations. The method is based on the theory by Derbenev and Skrinsky, (i.e. the Vlasov techique) and the electron cooling force is numerically calulated using adaptive Monte Carlo integration methods.

THPP053	One-dimensional Ordering of Protons by the Electron Cooling	ion, proton, heavy-ion, emittance	3485
	T. Shirai, M. Ikegami, A. Noda, H. Souda, M. Tanabe, H. Tongu Kyoto ICR, Uji, Kyoto M. Grieser MPI-K, Heidelberg I. N. Meshkov, A. V. Smirnov JINR, Dubna, Moscow Region K. Noda NIRS, Chiba-shi
	One of the main subjects of the compact cooler ring, S-LSR at Kyoto University is the physics of the ultra cold ion beam, such as the ordered beam and the crystalline beam, using the electron and laser cooling. The one-dimensional ordering of protons has been studied at S-LSR, while the ordering the highly charged heavy ions has been found at ESR and CRYRING. Abrupt jumps in the momentum spread and the Schottky noise power have been observed for protons at a particle number of around 2000. The beam temperature was 0.17 meV and 1 meV in the longitudinal and transverse directions at the transition, respectively. The normalized transition temperature of protons is close to those of heavy ions at ESR. The lowest longitudinal beam temperature below the transition was 0.3 K. It is close to the longitudinal electron temperature. The dependence of the ordering conditions on the betatron tune and the transverse beam temperature have been also studied. These results will be presented in the presentation.

THPP056	Simulations of Incoherent Vertical Ion Losses and Cooling Stacking Injection	ion, emittance, injection, proton	3494
	E. Syresin JINR, Dubna, Moscow Region
	The cooling stacking injection at a synchrotron is applied to obtain a high intensity of the stored coasting ion beam. The efficiency of cooling-stacking injection is defined mainly by two parameters: the cooling-accumulation efficiency and the ion life time. The life time of new injected ions usually is essentially smaller than the stack life time for high intensive ion beams. The incoherent loses of new injected ions are related to a multi scattering on residual gas atoms and a vertical heating caused by ion stack noise. The short life time of new injected ions restricts the efficiency of the cooling stacking injection The life time of new injected C⁶⁺ ions is shorter by 2 times than stack life time at HIMAC cooling stacking injection. The life time of new injected protons in S-LSR is smaller by 2-3 orders of magnitudes than the stack life time. The analytical estimations and BETACOL simulations of vertical incoherent ion losses and cooling stacking injection are presented.

THPP057	Electron Cooling Experiments at LEIR	ion, injection, controls, gun	3497
	G. Tranquille CERN, Geneva
	The LEIR electron cooler is the first of a new generation of coolers utilising high-perveance variable-density electron beams for the cooling and accumulation of heavy ion beams. It was commissioned at the end of 2005 and has since been routinely used to provide high brightness Pb ion beams required for future LHC ion runs. High perveance, or intensity, is required to rapidly reduce the phase-space dimensions of a newly injected “hot” beam whilst the variable density helps to efficiently cool particles with large betatron oscillations and at the same time improve the lifetime of the cooled stack. In this report we present the results of recent measurements made to check and to better understand the influence of the electron beam size, intensity and density profile on the cooling performance.

THPP058	Progress with Electron Beam System for the Tevatron Electron Lenses	gun, proton, cathode, simulation	3500
	V. Kamerdzhiev, G. F. Kuznetsov, G. W. Saewert, V. D. Shiltsev Fermilab, Batavia, Illinois
	We have developed , built and tested two novel electron guns for the Tevatron and RHIC electron lenses: the first, a gridded gun which generates electron beam profile with smoothed edges and broad flat-top; the second, Gaussian beam profile gun which can be used for generation of the profile with depressed emission in the center. We have also developed a new type of HV modulator for use in TELs. In this articel, we desicribe the guns and the modulator, and present results of the bench tests.

THPP072	Extinction Monitor by Using a Dissociation of Hydrogen Molecule to Atoms with High Energy Proton Beam	proton, ion, ion-source, monitoring	3527
	I. Itahashi, M. Aoki, Y. Arimoto, Y. Kuno, A. Sato, M. Y. Yoshida Osaka University, Osaka
	In a recent high current accelerator technology there are so many reasons for resulting in unwanted or hallow beam to be coped with, such as resonance crossing, space charge induced emittance growth and so on. For an extinction for bunched beam of less than 10^-7 order we need a particular scheme to diminish unwanted and hallow beam generated at not only spatial plane but also at longitudinal plane. In particular, the beam extinction between beam bunch is crucial for delayed coincidence measurements of intensity frontier and high sensitivity experiment such as muon to electron conversion and muon to electron gamma. The new detection method for the extinction is proposed by using a collision dissociation between a high energy proton with more than GeV energy and molecular ions. One path collision of high energy beam for molecular ion beam to be separated into atoms as well as its collision between stored molecular ions and high energy particles could be exploited for the monitor.

THPP086	Diamond Stripper Foil Experience at SNS and PSR	target, beam-losses, injection, plasma	3563
	R. W. Shaw, Y.-J. Chen, R. L. Coleman, D. M. Gardner, C. Luck, A. G. McDermott, M. A. Plum, L. L. Wilson ORNL, Oak Ridge, Tennessee M. J. Borden, T. Spickermann LANL, Los Alamos, New Mexico C. S. Feigerle University of Tennessee, Knoxville, Tennessee
	The SNS is currently operating at about 15% of the 1.4 MW design power, and the diamond stripper foils developed at ORNL continue to perform well. Several corrugated, nanocrystalline diamond stripping foils have been tested at SNS. Beyond about 300 C of injected charge, significant distortion and darkening of the foils is observed. These foils are currently limited in freestanding area to about 17x25 mm due to stress-induced tears in larger foils; this limit positions the residual silicon wafer mounting handle close enough to the circulating beam that additional losses have been observed. The PSR experience with these diamond foils has been promising, with the interesting observation that both the foil current due to secondary emission of electrons and the thermionic foil current are reduced for diamond foils relative to LANL/KEK foils. For comparable thickness foils, losses due to the Ho yield also appear to be higher for diamond. A recent development in our foil preparation has been a change to nano-seeded nucleation from the earlier microcrystal slurry ultrasonic abrasion technique. This has led to a more reproducible and uniform foil morphology with smaller crystallites.

THPP115	The Proposed ISAC-III Upgrade at TRIUMF	target, rfq, ion, proton	3635
	R. E. Laxdal, F. Ames, R. A. Baartman, P. G. Bricault, S. R. Koscielniak, M. Marchetto, M. Trinczek, F. Yan TRIUMF, Vancouver
	Presently, the ISAC facility produces radioactive ions by a single driver beam of up to 100microA of 500MeV protons (50kW) impinging on either of two production targets which are configured such that only one radioactive ion beam (RIB) is available for use at any one time; and the experimental hours are shared between several facilities in the low energy and two accelerated beam experimental areas. The ISAC-III upgrade is proposed to increase the number of RIBs simultaneously available to three. The upgrade involves the addition of a high power electron linac, 50MeV/10mA, that would irradiate one of two new independent targets and produce RIBs through photo-fission. A second beamline from the existing cyclotron would deliver an additional 500MeV 200microA proton beam to the new target area to irradiate the second target producing the third simultaneous beam. The proposal includes an additional post-accelerator front-end to augment the existing infrastructure to provide the capability of accelerating two of the RIBs simultaneously. The paper summarizes the upgrade and discusses design choices to optimize nuclide availability across the three experimental areas.

THPP124	Commissioning of the 150 MeV SSRF Linac	controls, linac, bunching, gun	3649
	M. H. Zhao, G. Q. Lin, W. H. Liu, B. L. Wang, J. Q. Zhang, S. P. Zhong, W. M. Zhou SINAP, Shanghai
	The 150 MeV SSRF linac has been integrated and commissioned from late 2006 to middle of 2007. This paper presents the design, installation, commissioning and status of this linac.

THPP143	Vacuum Design of the TPS Relates to the Beam Effects	vacuum, impedance, ion, photon	3699
	G.-Y. Hsiung, C. K. Chan, C.-C. Chang, H. P. Hsueh, Z.-D. Tsai NSRRC, Hsinchu J.-R. Chen NTHU, Hsinchu
	The concept of the vacuum design for the 3 GeV Taiwan Photon Source (TPS) considers several points of view which relates to the beam effects. The vacuum design of the low outgassing rate and the effective pumping configurations to obtain the lowest average pressure in the electron storage ring is to obtain the longer beam life time and the least of the ion trapping effect and the consequent problem of beam ion instability. The inner structure of the beam ducts provides the lower impedance which reduces the problems of the collective beam instability and the heating dissipation and damage to the vacuum components. The thin wall of the beam ducts and the bellows are designed for the sextupoles that offers the function of fast feedback orbit correction of the beam. The final performance of the third generation light source with low emittance will rely on the original design of vacuum systems for the electron beam. The design philosophy of the vacuum systems for the TPS will be described.

THPP151	Feasibility Study for High Performance Vacuum Chamber	photon, vacuum, storage-ring, positron	3720
	Y. Tanimoto KEK, Ibaraki
	For longer beam lifetime, many synchrotron light sources employ ante-chamber type of beam ducts to reduce photon- and electron-stimulated desorption gases around stored beams. Still more reduction, however, can be expected if an X-ray transparent membrane, such as Beryllium thin film, is installed between the beam chamber and the ante-chamber because X-rays from stored beams pass through the membrane while gas molecules desorbed in the ante-chamber are shut out by the membrane. Similarly, photoelectrons and secondary electrons traveling from the ante-chamber to the beam chamber are also shut out by the membrane; this function is expected to mitigate beam-photoelectron instability in positron storage rings. Feasibility study for this type of vacuum chamber has been started at PF, and the result of the first-stage experiment will be presented.

FRXAGM01	RHIC and its Upgrade Programs	luminosity, polarization, proton, ion	3723
	T. Roser BNL, Upton, Long Island, New York
	As the first hadron accelerator and collider consisting of two independent superconducting rings RHIC has operated with a wide range of beam energies and particle species. After a brief review of the achieved performance the presentation will give an overview of the plans, challenges and status of machine upgrades, that range from a new heavy ion pre-injector and beam cooling at 100 GeV to a high luminosity electron-ion collider.
	Slides

FRXCGM01	High Quality GeV Electron Beams from Plasma-Laser Accelerators	laser, 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