EPAC 2004 - List of Keywords

A B C D E F G H I K L M N O P Q R S T U V W

laser

Paper	Title	Other Keywords	Page
MOYCH01	The TESLA XFEL Project	electron, linac, photon, undulator	11
	H. Weise DESY, Hamburg
	The overall layout of the X-Ray FEL to be built in international collaboration at DESY will be described. This includes the envisaged operation parameters for the linear accelerator which will use TESLA technology. Main emphasis is put on the specification of the superconducting accelerator modules. Other linac components will be described as well. Work packages needed to finalize the linac design will be presented. A summary of the status of the preparation work will be given.
	Video of talk
	Transparencies

MOPKF008	The BESSY Soft X-ray FEL User Facility	undulator, photon, simulation, electron	312
	D. Krämer BESSY GmbH, Berlin
	A FEL User Facility for the VUV to soft X-ray spectral range is planned at the BESSY site based on a cascaded HGHG-FEL scheme. Simultaneous operation of 3 - later 5 - FELs fed by a superconducting 2.3 GeV CW linac generates most flexible pulse structures for experiments, while the seeding scheme utilizing Ti:Sa fs-lasers results in ultrashort reproducible circular polarized FEL pulses on a shot to shot basis at a pulse-duration < 20 fs. Peak brilliances in the 1·10³¹ ph/(s mm2 mrad2 0.1% bw)-regime are feasible. All necessary hardware for the FEL is within existing technology. Future upgrade options, e.g. a superconducting photoinjector, seeding with short wavelength HHG lasers of about 1 fs pulse duration have been considered. A status on the design aspects is given.

MOPKF010	The Output Performance of the BESSY Multi-stage HGHG-FEL	bunching, undulator, electron, polarization	318
	A. Meseck, M. Abo-Bakr, B.C. Kuske BESSY GmbH, Berlin
	The BESSY soft X-ray FEL is planned as a High Gain Harmonic Generatio(HGHG) FEL multi-user facility covering the VUV to soft X-ray spectral range(0.02 keV - 1. keV). A photoinjector and a superconducting 2.3GeV CW linac will feed three independent HGHG-FEL-lines. As the efficiency of the interaction between the radiation and the electron beam is higher in a helical undulator, one would tend to prefer such a device for the HGHG scheme. Also a higher K-value of the modulators seems to be advantageous. This is not necessarily the case. We present simulation studies for the BESSY-HGHG-FELs and discuss the output performance for ‘‘helical stages'' and increased K value of the modulators.

MOPKF015	A Superconducting Photo-Injector with 3+1/2- Cell Cavity for the ELBE Linac	gun, cathode, electron, pick-up	333
	J. Teichert, H. Buettig, P. Evtushenko, D. Janssen, U. Lehnert, P. Michel, Ch. Schneider FZR, Dresden W.-D. Lehmann IfE, Dresden J. Stephan IKST, Drsden V. Volkov BINP SB RAS, Novosibirsk I. Will MBI, Berlin
	After successful tests of an SRF gun with a superconducting half-cell cavity [], a new SRF photo-injector for CW operation at the ELBE linac has been designed. In this report the design layout of the SRF photo-injector, the parameters of the superconducting cavity and the expected electron beam parameters are presented. The SRF gun has a 31/2-cell niobium cavity working at 1.3 MHz and will be operated at 2 K. The three full cells have TESLA-like shapes. In the half-cell the photocathode is situated which will be cooled by liquid nitrogen. D. Janssen et. al., First operation of a superconducting RF-gun, Nucl. Instr. and Meth. A507(2003)314

MOPKF020	Proposal for a Sub-100 fs Electron Bunch Arrival-time Monitor for the VUV-FEL at DESY	electron, polarization, simulation, undulator	345
	H. Schlarb, S. Düsterer, J. Feldhaus, J. Hauschildt, R. Ischebeck, K. Ludwig, B. Schmidt, P. Schmüser, S. Simrock, B. Steffen, F. Van den Berghe, A. Winter DESY, Hamburg P.H. Bucksbaum, A. Cavalieri, D. Fritz, S. Lee, D. Reis Michigan University, Ann Arbor, Michigan
	For pump-probe experiments at the VUV-Free Electron Laser at DESY, an external optical laser system will be installed, capable of delivering ultra-short pulses of high intensity. The laser pulses with a center wavelength of 800 nm are synchronized with the VUV-FEL beam which covers the wavelength range between 6 nm and 80 nm. The expected pulse durations are typically 100 fs FWHM or below. For high-resolution pump-probe experiments a precise knowledge of the time difference between both pulses is mandatory. In this paper we describe the layout and the design of a high-precision electron bunch arrival time monitor based on an electro-optic technique. We present the numerical results of simulations that include: the laser propagation in a specifically designed demanding optical system, the laser transport through a 150 m long optical fibre, the electro-optically induced effect in different types of crystals and for different electron bunch shapes as well as the effects of wake fields on the co-propagating electric-fields and their impact on the observable signals.

MOPKF021	Properties of Cathodes Used in the Photoinjector RF Gun at the DESY VUV-FEL	cathode, gun, vacuum, insertion	348
	S. Schreiber DESY, Hamburg J.H. Han DESY Zeuthen, Zeuthen P. Michelato, L. Monaco, D. Sertore INFN/LASA, Segrate (MI)
	The new injector of the DESY VUV-FEL is being commissioned in spring 2004. Several cathodes have been tested in the photoinjector RF Gun. We report on quantum efficiency, dark current, and the overall appearance of the cathodes after their use.

MOPKF022	Commissioning of the VUV-FEL Injector at TTF	emittance, gun, electron, simulation	351
	S. Schreiber DESY, Hamburg
	The VUV-FEL at the TESLA Test Facility (TTF) at DESY is being upgraded to an FEL user facility serving high brilliance beams in the wavelength range from the VUV to soft X-rays. The photoinjector has been redesigned to meet the more demanding beam parameters in terms of transverse emittance, peak current, and energy spread. The first phase of the injector upgrade has been finished in spring 2004. We report on its commissioning, including first measurements of beam parameters.

MOPKF027	Optimizing the PITZ Electron Source for the VUV-FEL	emittance, electron, simulation, cathode	360
	M. Krasilnikov, J. Bähr, U. Gensch, H.-J. Grabosch, J.H. Han, D. Lipka, V. Miltchev, A. Oppelt, B. Petrosyan, D. Pose, L. Staykov, F. Stephan DESY Zeuthen, Zeuthen K. Abrahamyan YerPhI, Yerevan W. Ackermann, R. Cee, W.F.O. Müller, S. Setzer, T. Weiland TEMF, Darmstadt G. Asova, G. Dimitrov, I. Tsakov INRNE, Sofia I. Bohnet, J.-P. Carneiro, K. Floettmann, S. Riemann, S. Schreiber DESY, Hamburg M.V. Hartrott, E. Jaeschke, D. Krämer, R. Richter BESSY GmbH, Berlin P. Michelato, L. Monaco, C. Pagani, D. Sertore INFN/LASA, Segrate (MI) J. Rossbach Uni HH, Hamburg W. Sandner, I. Will MBI, Berlin
	The goal of the Photo Injector Test Facility at DESY Zeuthen (PITZ) is to test and optimize electron sources for Free Electron Lasers and future linear colliders. At the end of 2003 the first stage of PITZ (PITZ1) has been successfully completed, resulting in the installation of the PITZ RF gun at the Vacuum Ultra Violet - Free Electron Laser (VUV-FEL) at DESY Hamburg. The main results achieved during the PITZ1 extensive measurement program are discussed in this paper. A minimum normalized beam emittance of about 1.5 pi mm mrad for 1 nC electron bunch charge has been reached by optimizing numerous photo injector parameters, e.g. longitudinal and transverse profiles of the photocathode laser, RF phase, main and bucking solenoid current. The second stage of PITZ (PITZ2), being a large extension of the facility and its research program, has started now. Recent progress on the PITZ2 developments will be reported as well.

MOPKF030	"ARC-EN-CIEL" a Proposal for a 4th Generation Light Source in France	radiation, gun, electron, linac	366
	M.-E. Couprie, D. Garzella, B. Gilquin, P. Monot, L. Nahon CEA/DSM, Gif-sur-Yvette O.V. Chubar, A. Loulergue SOLEIL, Gif-sur-Yvette M. Desmons, M. Jablonka, F. Meot, A. Mosnier CEA/DSM/DAPNIA, Gif-sur-Yvette J.-R. Marquès LULI, Palaiseaux J.-M. Ortega LURE, Orsay A. Rousse LOA, Palaiseau
	An accelerator based 4th generation source is proposed to provide the user community with coherent femtosecond light pulses in the UV to X ray range. The project is based on a CW 700 MeV superconducting linac delivering high charge, subpicosecond, low emittance electron bunches with high repetition rate. This facility allows for testing High Gain Harmonic Generation seeded with high harmonics in gases, as well as the standard SASE mode, covering a spectral range down to 0.8 nm and 5 nm respectively. In addition, two beam loops are foreseen to increase the beam current in using the energy recovery technique. They will accommodate undulators for the production of femtosecond synchrotron radiation in the IR, VUV and X ray ranges together with a FEL oscillator in the 10 nm range.

MOPKF035	Stabilization of the Pulsed Regimes on Storage Ring Free Electron Laser: The Cases of Super-ACO and Elettra	feedback, electron, storage-ring, undulator	381
	C. Bruni, D. Garzella, G. Lambert, G.L. Orlandi LURE, Orsay E. Allaria, R. Meucci INOA, Firenze S. Bielawski PhLAM/CERCLA, Villeneuve d'Ascq Cedex M.-E. Couprie CEA/DSM, Gif-sur-Yvette M. Danailov, G. De Ninno, B. Diviacco, M. Trovò ELETTRA, Basovizza, Trieste D. Fanelli KTH/NADA, Stockholm L. Giannessi ENEA C.R. Frascati, Frascati (Roma)
	In a Storage Ring Free Electron Laser (SRFEL) a relativistic electron beam interacts with the magnetostatic periodic field of an undulator, thus emitting synchrotron radiation. The light is stored in an optical cavity and amplified during successive turns of the particles in the ring. The laser intensity may appear as a "continuous wave (cw)" or show a stable pulsed behaviour depending on the value of the temporal detuning, i.e. the difference between the electron beam revolution period and the round trip of the photons in the cavity. It was recently shown, that the loss of stability in a SRFEL occurs through an Hopf bifurcation []. This observation opens up the perspective of introducing a derivative self-controlled feedback to suppress locally the bifurcation and enlarge the region of stable signal. A feedback of this type has been implemented on Super-ACO and shown to produce a significant and reproducible extension of the stable "cw" region. We review here these results and discuss new experiments performed on the Super-ACO and ELETTRA SRFELs. G. De Ninno and D. Fanelli, Phys. Rev. Lett. in press; M.E. Couprie et al. Nucl. Instrum.and Meth. A., in press

MOPKF036	Wideband Infrared FEL	undulator, electron, vacuum, simulation	384
	J.-M. Ortega, F. Glotin, R. Prazeres LURE, Orsay
	The infrared free-electron laser offers the advantage of a potential large tunability since the FEL gain itself remains subtantially high throughout the infrared spectral range, provided that the electron beam quality remains sufficient at low energy. Moreover, the reflectivity of metal mirrors used in the optical cavity remains close to unity from the near infrared up to the microwave range. The main limitation comes from the diffraction of the optical beam due to the finite size of the vacuum chamber of the undulator and other optical cavity elements. The undulator magnetic gap, and thus magnetic chamber inner heigth, cannot be made arbitrarily large since one needs a K parameter sufficiently large to produce a large wavength tunability (typically K > 2). The diffraction losses can however be further reduced by using an elliptical vacuum chamber inside the undulator and elliptical, instead of spherical, mirrors. Then the optical beam is partially guided inside the chamber. Working in this regime at CLIO, we have obtained an FEL tunable from 3 to 120 μm by operating the accelerator between 50 and 14 MeV. This is the largest spectral range ever obtained with a single optical cavity. We plan to use larger mirrors to further reduce the diffraction produced at the edges of the undulator chambers in order to increase the maximum wavelength to approximately 200 μm

MOPKF037	FERMI@ELETTRA: 100 nm - 10 nm Single Pass FEL User Facility	linac, undulator, electron, radiation	387
	R.J. Bakker, C. Bocchetta, P. Craievich, G. D'Auria, M. Danailov, G. De Ninno, S. Di Mitri, B. Diviacco, G. Pangon, L. Rumiz, L. Tosi, V. Verzilov, D. Zangrando ELETTRA, Basovizza, Trieste
	The FERMI@ELETTRA project is an initiative from ELETTRA, INFM and other Italian institutes, to construct a single-pass FEL user-facility for the wavelength range from 100 nm (12 eV) to 10 nm (124 eV), to be located next to the third-generation synchrotron radiation facility ELETTRA in Trieste, Italy. The project is concentrated around the existing 1.2-GeV S-band linac, i.e., the injector for the storage ring. Presently the linac is only operational for approximately 2 hours per day. The remaining time is available for the construction and operation of an FEL but modifications and operation must be planned such that operation of the storage ring can be guaranteed until the completion of a new full-energy injector (spring 2006). At this moment the FEL project evolves from a conceptional design stage towards a technical design and the actual implementation. Key issues are: incorporation of the free-electron laser in the infrastructure of the Sincrotrone Trieste, adjustments of the linac to facilitate FEL operation, required additional civil engineering, undulator design, FEL seeding options, and beamline design. This paper serves as an overview of the project in combination with a discussion of the critical issues involved.

MOPKF040	Effect of Electron-beam Feedbacks on the ELETTRA Storage-ring Free-electron Laser	feedback, free-electron-laser, electron, storage-ring	393
	M. Trovò, D. Bulfone, M. Danailov, G. De Ninno, B. Diviacco, V. Forchi', M. Lonza ELETTRA, Basovizza, Trieste L. Giannessi ENEA C.R. Frascati, Frascati (Roma)
	As is well known, the stability of a storage-ring free-electron laser is strongly related to that of the electron beam. With respect to second-generation devices, such as Super ACO and UVSOR, the free-electron laser at ELETTRA is characterized by a noticeably higher gain and, consequently, shows to be much more sensitive to electron-beam instabilities. In order to counteract the impact of such instabilities, both a longitudinal multibunch and a local orbit feedbacks have been implemented for free-electron laser operation. Aim of this paper is to report on the beneficial effect of these feedback systems on the laser performance.

MOPKF042	Status of the SPARC Project	undulator, emittance, linac, gun	399
	M. Ferrario, D. Alesini, M. Bellaveglia, S. Bertolucci, M.E. Biagini, R. Boni, M. Boscolo, M. Castellano, A. Clozza, G. Di Pirro, A. Drago, A. Esposito, D. Filippetto, V. Fusco, A. Gallo, A. Ghigo, S. Guiducci, M. Incurvati, C. Ligi, F. Marcellini, L. Pellegrino, M.A. Preger, R. Ricci, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, F. Tazzioli, C. Vaccarezza, M. Vescovi, C. Vicario INFN/LNF, Frascati (Roma) F. Alessandria, A. Bacci, M. Mauri INFN/LASA, Segrate (MI) I. Boscolo, F. Brogli, S. Cialdi, C. De Martinis, D. Giove, C. Maroli, V. Petrillo, M. Romé, L. Serafini INFN-Milano, Milano L. Catani, E.C. Chiadroni, A. Cianchi, S. Tazzari Università di Roma II Tor Vergata, Roma F. Ciocci, G. Dattoli, A. Doria, F. Flora, G.P. Gallerano, L. Giannessi, E. Giovenale, G. Messina, L. Mezi, P.L. Ottaviani, L. Picardi, M. Quattromini, A. Renieri, C. Ronsivalle ENEA C.R. Frascati, Frascati (Roma) D. Dowell, P. Emma, C. Limborg-Deprey, D. Palmer SLAC, Menlo Park, California D. Levi, M. Mattioli, G. Medici Università di Roma I La Sapienza, Roma M. Migliorati, A. Mostacci, L. Palumbo Rome University La Sapienza, Roma P. Musumeci, J. Rosenzweig UCLA, Los Angeles, California M. Nisoli, S. Stagira, S. de Silvestri Politecnico/Milano, Milano
	The aim of the SPARC project is to promote an R&D activity oriented to the development of a high brightness photoinjector to drive SASE-FEL experiments at 500 nm and higher harmonics generation. It has been proposed by a collaboration among ENEA-INFN-CNR-Universita‘ di Roma Tor Vergata-INFM-ST and funded by the Italian Government with a 3 year time schedule. The machine will be installed at LNF, inside an existing underground bunker. It is comprised of an rf gun driven by a Ti:Sa laser to produce 10-ps flat top pulses on the photocathode, injecting into three SLAC accelerating sections. We foresee conducting investigations on the emittance correction and on the rf compression techniques up to kA level. The SPARC photoinjector can be used also to investigate beam physics issues like surface-roughness-induced wake fields, bunch-length measurements in the sub-ps range, emittance degradation in magnetic compressors due to CSR. We present in this paper the status of the design activities of the injector and of the undulator. The first test on diagnostic prototypes and the first experimental achievements of the flat top laser pulse production are also discussed.

MOPKF045	Cesium Telluride and Metals Photoelectron Thermal Emittance Measurements Using a Time-of-flight Spectrometer	emittance, electron, cathode, gun	408
	D. Sertore, D. Favia, P. Michelato, L. Monaco, P. Pierini INFN/LASA, Segrate (MI)
	The thermal emittance of photoemitted electrons in an RF gun is a crucial parameter for short wavelength FELs and future high luminosity electron colliders. An estimate of the thermal emittance of semiconductor and metal samples, commonly used as photocathodes, has been assessed using a Time-Of-Flight spectrometer. In this paper we present the analysis, based on angle resolved photoemission measurements, of both the cesium telluride (Cs2Te) photocathode films as used at the TESLA Test Facility, and polycrystalline metals. These latter measurements, at different laser wavelengths, are used to validate both our experimental apparatus and the thermal emittance reconstruction technique developed.

MOPKF056	Injector Design for the 4GLS Energy Recovery Linac Prototype	booster, emittance, electron, cathode	437
	C. Gerth, F.E. Hannon CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
	Daresbury Laboratory has been given funding for the construction of an Energy Recovery Linac Prototype (ERLP) that operates at a target electron beam energy of 35 MeV and drives an IR oscillator FEL. The ERLP serves as a test-bed for the study of beam dynamics and accelerator technology important for the design and construction of the proposed 4th Generation Light Source (4GLS). A key component of the ERLP is a high-brightness injector. The injector consists of a DC photocathode gun, which is currently being built at Daresbury Laboratory and based on the design of the gun for the IR demonstrator FEL at Thomas Jefferson National Accelerator Facility. The gun section is followed by a conventional buncher cavity, a super-conducting booster and a transfer line to the main linac. In this paper, the design of the ERLP injector is discussed. The performance of the injector has been studied using the particle tracking code ASTRA.

MOPKF072	Towards Attosecond X-ray Pulses from the FEL	electron, wiggler, radiation, lattice	482
	A. Zholents, J.M. Byrd, W. Fawley, Z. Hao, M.C. Martin, D. Robin, F. Sannibale, R.W. Schoenlein, M. Venturini, M.S. Zolotorev LBNL, Berkeley, California
	The ability to study ultrafast phenomena has been recently advanced by the demonstrated production and measurement of a single, 650-attosecond, soft x-ray pulses precisely synchronized to the pump laser pulse consisted of just few optical cycles. The next frontier is a production of attosecond x-ray pulses at even shorter wavelengths. Here we propose the method of ?seeded attosecond x-ray radiation? where an isolated, attosecond duration, short-wavelength x-ray pulse is radiated by electrons selected by their previous interaction with a few-cycle, intense laser pulse. In principle this method allows excellent synchronization between the attosecond x-ray probe pulse and a pump source that can be the same few-cycle laser pulse or another signal derived from it.

MOPKF074	Harmonic Cascade FEL Designs for LUX	undulator, electron, radiation, simulation	488
	G. Penn, J.N. Corlett, W. Fawley, M. Reinsch, W. Wan, J.S. Wurtele, A. Zholents LBNL, Berkeley, California
	LUX is a proposed facility for ultrafast X-ray science, based on an electron beam accelerated to GeV energies in a recirculating linac. Included in the design are short duration (200 fs or shorter FWHM) light sources using multiple stages of higher harmonic generation, seeded by a 190–250 nm laser of similar duration. This laser modulates the energy of a group of electrons within the electron bunch; this section of the electron bunch then produces radiation at a higher harmonic after entering a second, differently tuned undulator. Repeated stages in a cascade yield increasing photon energies up to 1 keV. Most of the undulators in the cascade operate in the low-gain FEL regime. Harmonic cascades have been designed for each pass of the recirculating linac up to a final electron beam energy of 3.1 GeV. For a given cascade, the photon energy can be selected over a wide range by varying the seed laser frequency and the field strength in the undulators. We present simulation results using the codes GENESIS and GINGER, as well as the results of analytical models which predict FEL performance. We discuss lattice considerations pertinent for harmonic cascade FELs, as well as sensitivity studies and requirements on the electron beam.

MOPKF083	Inverse Free Electron Laser Heater for the LCLS	electron, undulator, linac, gun	512
	R. Carr, L.D. Bentson, P. Bolton, D. Dowell, P. Emma, A. Gilevich, Z. Huang, J.J. Welch, J. Wu SLAC, Menlo Park, California
	The LCLS Free Electron Laser employs an RF photocathode gun that yields a 1 nC charge bunch a few picoseconds long, which must be further compressed to yield the high current required for SASE gain. The very cold electron beam from the RF photocathode gun is quite sensitive to microbunching instabilities such as coherent synchrotron radiation (CSR) in the compressor chicanes and longitudinal space charge (LSC) in the linac. These effects can be Landau damped by adding energy spread to the electron bunch prior to compression. We propose to do this by interacting an infrared laser beam with the electron bunch in an undulator added to the LCLS gun-to-linac injector. The undulator is placed in a 4-bend chicane to allow the IR laser beam to propagate co-linearly with the e-beam while it oscillates in the undulator. The IR laser beam is derived from the photocathode gun laser. Simulations presented elsewhere in these proceedings show that the laser interaction damps the microbunching instabilities to a very great extent. This paper is a description of the implementation of the laser heater

MOPKF085	Design Optimizations of X-ray FEL Facility at MIT	linac, electron, simulation, gun	518
	D. Wang, M. Farkhondeh, W. Graves, J. Van der Laan, F. Wang, T. Zwart MIT/BLAC, Middleton, Massachusetts P. Emma SLAC, Menlo Park, California
	MIT is exploring the construction of a linac-based x-ray laser user facility on the campus of the Bates Linear Accelerator Center. The facility under consideration would span the wavelength range from 100 to 0.3 nm in the fundamental, move into the hard X-ray region in the third harmonic, and preserve the possibility of an upgrade to even shorter wavelengths. The accelerator configuration would include a high brightness electron gun, a superconducting electron linac and multiple undulators and beam lines to support a growing user community. This paper will present the recent progress on the start-to-end simulations including the parameter optimizations and sensativity analysis.

MOPKF086	Modifications of the LCLS Photoinjector Beamline	emittance, gun, quadrupole, linac	521
	C. Limborg-Deprey, D. Dowell, S.M. Gierman SLAC, Menlo Park, California
	The LCLS Photoinjector beamline is now in the Design and Engineering stage. The fabrication and installation of this beamline is scheduled for the summer 2006. The Photoinjector will deliver 10 ps long electron bunches of 1nC with a normalized transverse emittance of less than 1 mm.mrad for 80% of the slices constituting the core of the bunch at 135 MeV. In this paper, we describe some modifications of the beamline: new exit energy, additional focusing, insertion of a laser heater. We also describe an alternate tuning which is based on a laser pulse of 20ps. The advantages and drawbacks of this long pulse tuning are reviewed. A comparison of sensitivity to field errors and misalignment between the long pulse tuning and the nominal tuning is given.

MOPLT001	Acceleration of Electrons by Spatially Modulated Laser Wave	electron, acceleration, vacuum, injection	527
	R.A. Melikian, M.L. Petrosyan, V.S. Pogosyan YerPhI, Yerevan
	We study the acceleration of electrons in a system of linearly polarized laser wave, propagating at small angles to the direction of electron motion. The parameters of electron bunch and laser wave are chosen so, that during driving electrons in a band of a wave, the electric field of a wave has not changed the direction. The requirements of deriving of maximum rate of acceleration are found depending on parameters of electronic bunch and laser wave. It is shown, that the dependence of growth of electrons energy from number of light bands has nonlinear character. The influence of light diffraction on process of acceleration is considered. It is shown, that the discussed scheme of acceleration allows a possibility of deriving of high acceleration rate owing to existence of modern powerful lasers.

MOPLT013	Fatigue Testing of Materials by UV Pulsed Laser Irradiation	linac, simulation, vacuum, radiation	557
	S. Calatroni, H. Neupert, M. Taborelli CERN, Geneva
	The energy dissipated by the RF currents in the cavities of high-power pulsed linacs induces cycles of the surface temperature. In the case of the CLIC main linac the expected amplitude of the thermal cycles is about hundred degrees, for a total number of pulses reaching 10e11. The differential thermal expansion due to the temperature gradient in the material creates a cyclic stress that can result in surface break-up by fatigue. The materials for cavity fabrication must therefore be selected in order to withstand such constraints whilst maintaining an acceptable surface state. The fatigue behaviour of Cu and CuZr alloy has been tested by inducing larger surface peak temperatures, thus reducing the number of cycles to failure, irradiating the surface with 50 ns pulses of UV light (308 nm) from an excimer laser. Surface break-up is observed after different number of laser shots as a function of the peak temperature. CuZr appears to withstand a much larger number of cycles than Cu, for equal peak temperature. The characterization of the surface states and possible means of extrapolating the measured behaviour to the expected number of pulses of CLIC are discussed in detail.

MOPLT061	Design Study for Advanced Acceleration Experiments and Monochromatic X-ray Production @ SPARC	electron, photon, plasma, acceleration	695
	L. Serafini, S. Cialdi, R. Pozzoli, M. Romé INFN-Milano, Milano D. Alesini, S. Bertolucci, M.E. Biagini, C. Biscari, R. Boni, M. Boscolo, M. Castellano, A. Clozza, G. Di Pirro, A. Drago, A. Esposito, M. Ferrario, V. Fusco, A. Gallo, A. Ghigo, S. Guiducci, M. Incurvati, C. Ligi, F. Marcellini, M. Migliorati, C. Milardi, L. Palumbo, L. Pellegrino, M.A. Preger, P. Raimondi, R. Ricci, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, F. Tazzioli, C. Vaccarezza, M. Vescovi, C. Vicario, M. Zobov INFN/LNF, Frascati (Roma) F. Alessandria, A. Bacci, F. Broggi, C. De Martinis, D. Giove, M. Mauri INFN/LASA, Segrate (MI) R. Bonifacio, I. Boscolo, C. Maroli, V. Petrillo, N. Piovella Universita' degli Studi di Milano, MILANO A. Mostacci Rome University La Sapienza, Roma
	We present a design study for an upgrade of the SPARC photo-injector system, whose main aim is the construction of an advanced beam test facility for conducting experiments on high gradient plasma acceleration and for the generation of monochromatic X-ray beams to be used in advanced medical applications and condensed matter physics studies. Main components of the proposed plan of upgrade are: two additional beam lines with interaction regions for synchronized high brightness electron and high intensity photon beams and the upgrade of the SPARC Ti:Sa laser system to reach a multi-TW power level (in excess of 1 J in pulse energy). Results of numerical simulations modeling the interaction of the SPARC electron beam and the counter-propagating laser beam are presented with detailed discussion of the monochromatic X-ray beam spectra generated by Compton backscattering: X-ray energies are tunable in the range 20 to 500 keV, with pulse duration from sub-ps to 30 ps. Preliminary simulations of plasma acceleration of the SPARC electron beam, generated in ultra-short bunches, via the LWF mechanism and with external injection are also shown: experiments of self-injection are also foreseen and illustrated.

MOPLT072	Effects of Positrons on Relativistic Solitons in Laser-Plasma Interactions	ion, positron, electron, plasma	719
	J.B. Kim, I.S. Ko POSTECH, Pohang, Kyungbuk H. Suk KERI, Changwon
	An extended 1D kinetic model of relativistic solitons by high power lasers in three species plasmas is suggested and it is applied to analysis on the effects of electron-positron pairs on the solitons. Stability condition of the solitons is derived. The range of parameters for the stable solitons are specified in the frequency-temperature plane. With the creation of electron-positron pairs, relativistic solitons appear stable in wider range of frequencies and temperatures. The regions are expanded toward higher values in overall ranges in the frequency-temperature plane. The stability conditions are affected by the density of positrons. The variation of shapes, peak E-field, and width of the solitons by varying the positron density are analyzed. We discuss the implications of the variation in the soliton on the ion accelerations by it.

MOPLT073	Picosecond High Voltage Switching for Pulsed DC Acceleration	acceleration, electron, plasma, pulsed-power	722
	J. Hendriks, G.J.H. Brussaard TUE, Eindhoven
	Laser wakefield acceleration promises the production of high energy electrons from table-top accelerators. External injection of a (low energy) electron bunch into a laser wakefield requires acceleration gradients of the order GV/m. In principle DC acceleration can achieve GV/m acceleration gradients. If high voltage pulses of the order MV can be switched with picosecond precision, the performance of such an accelerator would be greatly enhanced and even multistage DC acceleration would become feasible. Presently risetime and jitter of high voltage pulses in high voltage laser triggered spark gaps are limited to the nanosecond regime by the initial stochastic breakdown process in the gap. A way to overcome this limitation is to create a line focus between the electrodes with an intensity above 10¹⁸ W/m² using a high power femtosecond Ti:Sapphire laser. Because of the instantaneous ionization and high degree of ionization in the plasma channel, picosecond switching precision can be achieved and jitter is reduced significantly. A spark gap test setup with 3 mm interelectrode distance has been build and the first measurements have been done. Femtosecond diagnostics for characterization of the laser induced plasma and electro-optic diagnostics for the high voltage pulse have been developed.

MOPLT102	To the Problem of Wake-field Excitation for Advanced Accelerator Concept	electron, radiation, acceleration, plasma	770
	I.N. Onishchenko, V. Kiselev, A. Linnik, N. Onishchenko, G. Sotnikov NSC/KIPT, Kharkov V. Ushkov RRC Kurchatov Institute, Moscow
	The advanced accelerator concept to use the wake-fields exited in dielectric by a sequence of electron bunches for high-gradient particle acceleration has been proposed and investigated in [-]. Two essential merits are being exploited. First of them [] is the excitation by a regular sequence of electron bunches that allows superposing coherently the wake-fields excited by each bunch. The second one [**] concludes to multi-mode operation that leads to peaking of the resulting HF-field that is represented by a sequence of spikes of alternative signs with essentially higher amplitude comparatively to only principle mode excitation. The recent works performed in NSC/KIPT on theoretical studies, simulation, and experimental investigations of the wake-fields excitation by a train of 2 MeV electron bunches in a dielectric waveguide are presented. Transition and Cerenkov radiation excited by short bunches in a limited dielectric medium was theoretically investigated. The measurements of wake-fields output power and the electron energy spectrum were experimentally performed. W.Gai, P.Schoessow, B.Cole et al. Phys. Rev. Lett. 61, 2756 (1988) I.N.Onishchenko, V.A.Kiselev, G.V.Sotnikov et al. Proc. 1995 Particle Accelerator Conf., p. 782-3* T.B.Zhang, J.L.Hirshfield, T.C.Marshall et al Proc. 1997 Particle Accelerator Conf., V.42, No.3, p.1341

MOPLT117	An Electron Front End for the Fermilab Multi-species 8 GeV SCRF Linac	linac, electron, emittance, injection	809
	P. Piot, G.W. Foster Fermilab, Batavia, Illinois
	Fermilab is considering 8 GeV superconducting linac whose primary mission is to serve as an intense H^- injector for the main injector. This accelerator is also planned to be used for accelerating various other species (e.g. electrons and muons). In the present paper we investigate the possibility of such a linac to accelerate a high brightness electron beam to ~7 GeV. We propose a design for the electron front end, based on a photoinjector, and consider the electron beam dynamics along the linac. Start-to-end simulations of the full accelerator for electrons are presented. Finally the potential applications of the such an electron beam are discussed.

MOPLT151	Study of Arc-related RF Faults in the CEBAF Cryomodules	vacuum, ion, linac, electron	890
	E. Daly, D. Curry, J. Musson, G. Myneni, T. Powers, H. Wang, T.E. Whitlatch Jefferson Lab, Newport News, Virginia I.E. Campisi ORNL/SNS, Oak Ridge, Tennessee
	A series of measurements has been conducted on two superconducting radio-frequency cavity pairs, installed in cryomodules and routinely operated in the Continuous Electron Beam Accelerator Facility, in order to study the RF-vacuum interaction during an RF fault. These arc-related fault rates increase with increasing machine energy, contribute to system downtime and directly affect the accelerator?s availability. For this study, the fundamental power coupler waveguides have been instrumented with vacuum gauges, additional arc detectors, additional infrared sensors and temperature sensors in order to measure the system response during both steady-state operations and RF fault conditions. Residual gas analyzers have been installed on the waveguide vacuum manifolds to monitor the gas species present during cooldown, RF processing and operation. Simultaneous measurements of the signals are presented, a comparison with analysis is shown and results are discussed. The goal of this study is to characterize the RF-vacuum interaction during normal operations. With a better understanding of the installed system response, methods for reducing the fault rate may be devised, ultimately leading to improvements in availability.

TUYACH01	Laser-acceleration and Laser-cooling for Ion Beams	ion, proton, target, acceleration	54
	M. Roth, A. Blazevic, E. Brambrink, M. Geissel TU Darmstadt, Darmstadt P. Audebert LULI, Palaiseaux M. Bussmann, D. Habs, U. Schramm, J. Schreiber LMU, München R. Clarke, S. Karsch, D. Neely CCLRC/RAL, Chilton, Didcot, Oxon J.A. Cobble, J. Fernandez, M. Hegelich, S. Letzring LANL, Los Alamos, New Mexico T.E. Cowan, J. Fuchs, A. Kemp, H. Ruhl University of Nevada, Reno, Reno, Nevada K. Ledingham, P. McKenna Strathclyde University, Glasgow
	The acceleration or cooling of particles with lasers has been the subject of growing interest over the last years. Because of the huge difference in mass, the acceleration of ions was so far limited to thermal expansion from laser plasmas, driven by the hot electron temperature. In recent years, due to the development of short-pulse ultra-intense lasers, the manipulation of ions has now become possible. Especially the generation of high quality, intense ion beams from laser solid interaction has attracted large attention and is investigated at many laboratories world-wide. For the first time, intense, directed, low emittance beams of ions have been observed, having several MeV of particle energy right from the source. A wealth of applications including next generation ion sources can be envisioned. The talk will give an overview of the status of laser cooling and ion acceleration including the last experimental results. In addition, an overview of the current and future research activities will be presented.
	Video of talk
	Transparencies

TUYBCH02	Technological Challenges for High Brightness Photo-injectors	electron, gun, vacuum, brightness	64
	G. Suberlucq CERN, Geneva
	Many applications, from linear colliders to free-electron lasers, passing through light sources and many other electron sources, require high brightness electron beams, usually produced by photo-injectors. Because certain parameters of these applications differ by several orders of magnitude, various solutions were implemented for the design and construction of the three main parts of the photo-injectors: lasers, photocathodes and guns. This paper summarizes the different requirements, how they lead to technological challenges and how R&D programs try to overcome these challenges. Some examples of state-of-the-art parts are presented.
	Video of talk
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TUZACH02	Ultra-high Gradient Compact Accelerator Developments	plasma, electron, acceleration, injection	74
	G.J.H. Brussaard, M.J. Van der Wiel TUE, Eindhoven
	Continued development of relatively compact, although not quite 'table-top', lasers with peak powers in the range up to 100 TW has enabled laser-plasma-based acceleration experiments with amazing gradients of up to 1 TV/m. In order to usefully apply such gradients to 'controlled' acceleration, various hurdles need to be overcome. The main one is that of well-synchronized injection into a sub-mm to micron wavelength plasma wave. The talk will describe the various physics regimes of laser wakefield acceleration, and the two classes of experiments being pursued. One is that of atmospheric-density plasmas, non-linear wakefields with extreme gradients (hundreds of GV/m)and 'internal injection' of few-femtosecond electron bunches. A second class involves modest-density plasmas,wakefields of order 1 GV/m and external injection of (sub)-ps bunches. The state-of-the-art of these experiments will be covered, including the progress on plasma waveguiding of TW pulses over many diffraction lengths. The talk will also provide an outlook for the coming few years. This part includes proposed schemes for improvements in the area of injection, such as 'all-optical' injection and injection based on GV/m 'pulsed-DC' photoguns.
	Video of talk
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TUPKF025	Superconducting Niobium Film for RF Applications	cathode, vacuum, plasma, electron	1021
	A. Cianchi, L. Catani, A. Cianchi, S. Tazzari INFN-Roma II, Roma Y.H. Akhmadeev Institute of High Current Electronics, Tomsk A. Andreone, G. Cifariello, E. Di Gennaro, G. Lamura Naples University Federico II, Napoli J.L. Langner The Andrzej Soltan Institute for Nuclear Studies, Centre Swierk, Swierk/Otwock R.R. Russo Università di Roma II Tor Vergata, Roma
	Thin niobium film coated copper RF cavities are an interesting possible alternative to bulk-Nb cavities since copper is much cheaper than niobium, it has higher thermal conductivity and a better mechanical stability. Unfortunately, the observed degradation of the quality factor with increased cavity voltage of sputtered accelerating cavities restricts their usage in future large linear accelerators needing gradients higher than 15MV/m. We are developing an alternate deposition technology, based on a cathodic arc system working in UHV conditions. Its main advantages compared to standard sputtering are the ionized state of the evaporated material, the absence of gases to sustain the discharge, the much higher energy of atoms reaching the substrate surface and the possibility of higher deposition rates. To ignite the arc we use a Nd-YAG pulsed laser focused on the cathode surface that provides a reliable and ultraclean trigger. Recent results on the characterization of niobium film samples produced under different conditions are presented showing that the technique can produce bulk-like films suitable for RF superconducting applications.

TUPKF065	Comparison of Klystron and Inductive Output Tubes (IOT) Vacuum-electron Devices for RF Amplifier Service in Free-electron Laser	klystron, electron, cathode, vacuum	1093
	A. Zolfaghari, P. MacGibbon, W. North MIT/BLAC, Middleton, Massachusetts
	The MIT X-Ray Laser project, conceived to produce output in the 0.3 to 100 nanometer range, is based on a super-conducting 4-GEV linear accelerator, using 24 multi-cavity cryo-modules, each with its own dedicated RF amplifier, operating at 1.3 GHz. The continuous output of each amplifier is nominally 15 kW, with an optional repetitive pulse-modulation mode of 0.1 second pulse duration at one pulse per second. Although there are no fundamental restraints which preclude the consideration of any RF amplifier type, including solid-state or conventional triode or tetrode, the most appropriate current technology includes the Klystron and the IOT (Inductive Output Tube), also known by the CPI trade-name, Klystrode. The mechanisms by which the devices convert DC input power into RF output power are discussed. The devices are then compared with regard to availability (developmental or off-the-shelf), conversion efficiency, means of pulse-modulation, RF power gain, phase and amplitude stability (pushing factors), and acquisition and life-cycle costs.

TUPKF080	Photoemission Properties of Lead	cathode, electron, heavy-ion, vacuum	1126
	J. Smedley, T. Srinivasan-Rao, J. Warren BNL, Upton, Long Island, New York R.S. Lefferts, A.R. Lipski SBUNSL, Stony Brook, New York J. Sekutowicz Jefferson Lab, Newport News, Virginia
	There is significant interest in the possibility of building a super-conducting injector for high average current accelerator applications. One candidate for such a cavity design is superconducting lead. Such an injector would be made considerably simpler if it could be designed to use lead as the photocathode, eliminating the need for Cesiated materials in the injector. In this paper we present a study of the photoemission properties of lead at several UV wavelengths, including a study of the damage threshold of electroplated lead under laser cleaning. A quantum efficiency in excess of 0.1% has been achieved for a laser cleaned, electroplated lead sample with a laser wavelength of 193 nm.

TUPLT021	Heavy Ion Beam Transport in Plasma Channels	plasma, ion, heavy-ion, beam-transport	1183
	S. Neff, D.H. Hoffmann, R. Knobloch TU Darmstadt, Darmstadt C. Niemann, D. Penache, A. Tauschwitz GSI, Darmstadt S. Yu LBNL, Berkeley, California
	The transport of heavy ion beams in high current discharge channels is a promising option for the final beam transport in a heavy ion fusion reactor. The channel provides space-charge neutralization and an azimuthal magnetic field of several tesla, thereby allowing for transporting high current ion beams. The possibility to heat the hohlraum target with only two ion beams simplifies the reactor design significantly. Therefore channel transport is studied as part of the US fusion reactor study as an alternative to neutralized ballistic focusing. We have created 1 m long discharge channels and studied the channel development and stability. In addition, we have carried out proof-of-principle transport experiments using the UNILAC facility at the Gesellschaft für Schwerionenforschung. The experiments demonstrate the feasibility of plasma channel transport. Our transport experiments with low current beams are supplemented by simulations for high current beams. These simulations show the possibility of transporting particle currents of up to 60 kA.

TUPLT025	Matching of a C⁶⁺ Ion Beam from a Laser Ion Source to a RFQ	ion, rfq, injection, ion-source	1195
	R. Becker, R.A. Jameson, A. Schempp IAP, Frankfurt-am-Main T. Hattori RIKEN, Saitama N. Hayashizaki, H. Kashiwagi RLNR, Tokyo M. Okamura RIKEN/RARF/CC, Saitama K. Yamamoto RIKEN/RARF/BPEL, Saitama
	A laser ion source, driven by a Nd-YAG laser can provide more than 100 mA of C⁶⁺ ions for a duration of about 1 μs, which is well matching the task of single-turn injection into synchrotrons for hadron tumor therapy with light ions. The ?direct? injection scheme has been improved by providing a design, which reduces the surface field strength to less than 30 kV/cm on all critical parts on relative negative potential. The new design keeps the advantage of divergent ion emission and acceleration, which seems to be the only way to keep the surface fields in limits, but includes a decelerating electrostatic lens on birth potential of the ions to refocus the emerging ion beam to the RFQ entrance. The whole design is very compact and allows for electrostatic steering between the ion source and the RFQ.

TUPLT061	Production and Transport of Radioactive Francium for Magneto-optical Trapping	target, ion, extraction, quadrupole	1294
	G. Stancari, R. Calabrese, B. Mai, G. Stancari, L. Tomassetti INFN-Ferrara, Ferrara S.N. Atutov, V. Guidi UNIFE, Ferrara V. Biancalana, A. Burchianti, A. Khanbekyan, C. Marinelli, E. Mariotti, L. Moi, S. Veronesi UNISI, Siena L. Corradi, A. Dainelli INFN/LNL, Legnaro, Padova P. Minguzzi, S. Sanguinetti UNIPI, Pisa
	An innovative facility for the production and trapping of francium isotopes is operating at the INFN laboratories in Legnaro, Italy. The goal is to obtain a dense cloud of cold and possibly polarized radioactive atoms for a wide range of fundamental studies. Among them are high-resolution laser spectroscopy, alpha-decay asymmetries from deformed nuclei, and tests of the standard model at low transferred momenta. The production of francium is achieved by sending a 100-MeV oxygen-18 beam from the Tandem-XTU accelerator on a thick gold target. The extraction of Fr+ is enhanced by heating the target to 1200 K and by biasing it at +3 kV. The ions are transported to the magneto-optical trap (MOT) through a 7-m electrostatic beam line. The diagnostic systems for monitoring the beam intensity (10⁵ ions/s) are based on silicon detectors sensitive to the alpha particles from Fr decays. Beams of stable Rb+ can also be used for optimizing the transport and trapping processes. Prior to injection into the MOT the beam is neutralized and released in atomic form by a heated yttrium or zirconium foil. Details on the production, transport and neutralization processes are presented.

TUPLT063	Laser Temporal Pulse Shaping Experiment For SPARC Photoinjector	emittance, electron, insertion, feedback	1300
	C. Vicario, A. Ghigo INFN/LNF, Frascati (Roma) I. Boscolo, C. Vozzi Universita' degli Studi di Milano, MILANO S. Cialdi, A.F. Flacco INFN-Milano, Milano M. Nisoli, G. Sansone, S. Stagira Politecnico/Milano, Milano M. Petrarca INFN-Roma, Roma
	Laser for driving high brightness photoinjector have to produce UV square pulse which is predicted to be the optimum profile for emittance compensation in advanced photoinjectors. The longitudinal laser pulse distribution, according to numerical simulations for the SPARC photoinjector, must be square with rise and fall time shorter than 1 ps and flat top variable up to 10 ps FWHM. In this paper we report the results of pulse shaping obtained using an acousto-optic (AO) programmable dispersive filter (DAZZLER). The DAZZLER was used to perform spectral amplitude and phase modulation of the incoming 100 fs Ti:Sapphire pulses. Because of the finite length of the crystal the maximum duration of the shaped pulse is 6 ps. To overcome this limitation we used a configuration in which the laser pulses passed twice through the AO filter. A dispersive glass section was also used to lengthen the pulse with a single pass in the DAZZLER. In this paper we report the experimental setup, hardware description and time and frequency domain measurements.

TUPLT082	Generation of a Femtosecond Electron Beam for Nanoscience and Nanotechnology	electron, gun, linac, emittance	1348
	J. Yang, T. Kozawa, S. Tagawa, Y. Yoshida ISIR, Osaka
	A new S-band femtosecond electron linear accelerator was developed in Osaka University for the study of radiation-induced ultrafast physical and chemical reactions in femtosecond time regions. The femtosecond electron accelerator was constructed with a laser driven photocathode RF gun, a linear accelerator (linac) and a magnetic pulse compressor. The RF gun was driven by a mode-locked Nd:YLF picosecond laser. The electron beam produced by the RF gun was accelerated in the linac with energy modulattion by adjusted the RF phase. The magnetic pulse compression, which was constructed with two 45o-bending magnets and four quadrupole magnets, is a technique to longitudinally focus a charged beam by rotating the phase space distribution in a magnetic field. The picosecond electron pulse, which was generated in the RF gun and accelerated in the linac with energy modulation, was compressed into femtosecond by adjusted the quadrupole magnetic fields. The femtosecond electron pulse is expected for the studies of ultrafast reactions in nano-space.

TUPLT086	A 40MeV Electron Source with a Photocathode for X-ray Generation through Laser-compton Scattering	electron, linac, emittance, gun	1354
	F. Sakai, N. Nakajyo, Y. Okada, T. Yanagida, M. Yorozu SHI, Tokyo
	.3 keV femtosecond X-ray generation through laser-Compton scattering with 14MeV electron source and a TW Ti:sapphire laser was achieved. In order to increase the X-ray energy up to 15 keV for some applications, e.g. protein crystallography, we modified the system to increase electron energy. Electron beams emitted from a S-band RF photocathode are accelerated up to 40MeV with two 1.5m standing-wave linacs. The beams are bended at 90 degree using an achromatic bending system, then focused with a triplet quadrupole-magnet to be interacted with laser pulses. The characteristics of electron beams, emittance, energy and energy dispersion, will be described.

TUPLT088	Beam Cooling at S-LSR	ion, electron, resonance, coupling	1360
	A. Noda, H. Fadil, S. Fujimoto, M. Ikegami, T. Shirai, M. Tanabe, H. Tongu Kyoto ICR, Uji, Kyoto M. Grieser MPI-K, Heidelberg I.N. Meshkov, E. Syresin JINR, Dubna, Moscow Region K. Noda, T. Takeuchi NIRS, Chiba-shi H. Okamoto, Y. Yuri HU/AdSM, Higashi-Hiroshima
	S-LSR is an ion accumulation and cooler ring with the circumference and maximum magnetic rigidity of 22.589 m and 1.0T.m, respectively. Electron beam cooling will be applied for laser-produced hot ion beam after phase rotation. Electron cooler for S-LSR is now under construction and the beam simulation is also going on. Laser cooling of Mg ion with low energy (35 keV) is also planned in 3-dimensional way with use of Synchro-Betatron coupling.so as to realize ultra cold beam. Cancellation of shear force due to orbit-length difference in the dipole section is to be studied with use of overlapping of the radial electric field inversely proportional to the curvature radius with the uniform vertical magnetic field. Possible experiments to approach to ultra-cold beam is also to be studied by computer simulation

TUPLT106	New Developments of a Laser Ion Source for Ion Synchrotrons	ion, ion-source, extraction, target	1402
	S. Kondrashev, A. Balabaev, K. Konukov, B.Y. Sharkov, A. Shumshurov ITEP, Moscow O. Camut, J. Chamings, H. Kugler, R. Scrivens CERN, Geneva A. Charushin, K. Makarov, Y. Satov, Y. Smakovskii SRC RF TRINITI, Moscow region
	Laser Ion Sources (LIS) are well suited to filling synchrotron rings with highly charged ions of almost any element in a single turn injection mode. We report the first measurements of the LIS output parameters for Pb²⁷⁺ ions generated by the new 100 J/1 Hz Master Oscillator - Power Amplifier CO2-laser system. A new LIS has been designed, built and tested at CERN, as an ion source for ITEP-TWAC accelerator/accumulator facility, and as a possible future source for an upgrade of the Large Hadron Collider (LHC) injector chain. The use of the LIS based on 100 J/1 Hz CO2-laser together with the new ion LINAC, as injector for ITEP-TWAC project is discussed.

TUPLT128	The Operation Modes of Kharkov X-ray Generator based on Compton Scattering NESTOR	electron, photon, storage-ring, scattering	1428
	A.Y. Zelinsky, E.V. Bulyak, P. Gladkikh, I.M. Karnaukhov, A. Mytsykov, A.A. Shcherbakov NSC/KIPT, Kharkov T.R. Tatchyn SLAC/SSRL, Menlo Park, California
	The results of theoretical and numerical considerations of linear Compton scattering are used to evaluate characteristics of X-rays produced by collision between a low emittance electron beam and intensive laser light in an X-rays generator NESTOR of NSC KIPT. Two main generation modes have been under consideration at preliminary NESTOR design. There are the operation mode for medicine 33.4 keV X-rays production using 43 Mev electron beam and Nd:YAG laser beam and higher energy X-rays production mode providing X-rays with energy up to 900 keV with 225 MeV electron beam and Nd:YAG laser beam. It is supposed to use an optical cavity for laser beam accumulation of about 2.6 m long and an interaction angle of about 30 in both operation modes. A few more operation modes provide possibility to expand operation range of NESTOR. Using interaction angle 100 and 1500 along with optical resonator 42 or 21 cm long and the second mode of laser light it is possible to produce X-rays in energy range from a few keV till 1.5 MeV. The intensity and spectral brightness of the X-rays is expected to be ~ 1013 phot/s and ~ 1013 phot/s/mm2/mrad2/0.01%BW respectively.

TUPLT129	NESTOR Reference Orbit Correction	electron, pick-up, radiation, storage-ring	1431
	V.A. Ivashchenko, P. Gladkikh, I.M. Karnaukhov, A. Mytsykov, V.I. Trotsenko, A.Y. Zelinsky NSC/KIPT, Kharkov
	It is known that intensity of scattered radiation in X-rays generators based on Compton scattering strongly depends on relative position of electron and laser beams. For this reason it is very important to have effective system of reference orbit correction and beam position control as well along whole ring as at the interaction point. In the paper the results of design and development of reference orbit correction system for compact storage ring NESTOR are presented. The total reference orbit correction will be carried out in vertical plane only. Correctors will be disposed on quadrupole lenses and will be provide reference orbit correction angle up to 0.10. The local correction at the interaction point will be provided with four correctors located at the interaction straight section. In the article results of calculations, layout of whole system, quadrupole lenses and pick-up station parameters and schemes are presented.

TUPLT134	Lattice of NSC KIPT Compact Intense X-ray Generator NESTOR	electron, storage-ring, lattice, sextupole	1440
	A.Y. Zelinsky, P. Gladkikh, I.M. Karnaukhov, V. Markov, A. Mytsykov, A.A. Shcherbakov NSC/KIPT, Kharkov
	The new generation of the intense X-rays sources based on low energy electron storage ring and Compton scattering of laser beam allows to produce X-rays with intensity up to 1014 phot/s. One of the main traits of a storage ring lattice for such generator type is using of magnetic elements with combined focusing functions such as bending magnets with quadrupole and sextupole field components. In combination with very low bending radius and dense magnetic elements setting along ring circumference it leads to increasing of 3D magnetic field effects on electron beam dynamics and can decrease generated radiation intensity drastically. For the reasons of very low electron beam size at the interaction point and strong focusing in a compact storage ring the questions of determination of accuracy of bending magnet is very important too. The paper is devoted to the description of lattice of NSC KIPT Compact X-ray generator NESTOR. The results of investigations of the effects of 3D magnetic field and harmonic compound due to manufacture errors of bending magnets, bending magnet and lenses edges on electron beam dynamics are presented.

TUPLT162	Computation of the Longitudinal Space Charge Effect in Photoinjectors	simulation, linac, space-charge, bunching	1506
	C. Limborg-Deprey, P. Emma, Z. Huang, J.J. Welch, J. Wu SLAC, Menlo Park, California
	The LCLS Photoinjector produces a 100A, 10 ps long electron bunch which is later compressed down to 100 fs to produce the peak current required for producing SASE radiation. SASE saturation will be reached in the LCLS only if the emittance and uncorrelated energy spread remain respectively below 1.2 mm.mrad and 5. 10^-4. This high beam quality will not be met if the Longitudinal Space Charge (LSC) instability develops in the injector and gets amplified in the compressors. The Longitudinal Space Charge instability originates in the injector beamline, from an initial modulation of the current density. Numerical computations, performed with Multiparticle Space Charge tracking codes, showing the evolution of the longitudinal phase space along the LCLS Photoinjector beamline, are presented. Those results are compared with an analytical model for various regimes of energy and acceleration. This study justifies the necessity to insert a "laser heater" in the LCLS Photoinjector beamline to warm up the beam and thus prevent the amplification of the LSC instability in the compressors. Numerical calculations of the 'laser heater' performances are presented.

TUPLT164	CEBAF Injector Achieved World's Best Beam Quality for Three Simultaneous Beams with a Wide Range of Bunch Charges	space-charge, gun, electron, cathode	1512
	R. Kazimi, K. Beard, F.J. Benesch, A. Freyberger, J.M. Grames, T. Hiatt, A. Hutton, G.A. Krafft, L. Merminga, M. Poelker, M. Spata, M. Tiefenback, B.C. Yunn, Y. Zhang Jefferson Lab, Newport News, Virginia
	The CEBAF accelerator simultaneously provides three 499 MHz interleaved continuous electron beams spanning 5 decades in beam intensity (a few nA to 200 uA) to three experimental halls. The typical three-user physics program became more challenging when a new experiment, G0, was approved for more than six times higher bunch charge than is routine. The G0 experiment requires up to 8 million electrons per bunch (at a reduced repetition rate of 31 MHz) while the lowest current hall operates at 100 electrons per bunch simultaneously. This means a bunch destined to one hall may experience significant space charge forces while the next bunch, for another hall, is well below the space charge limit. This disparity in beam intensity is to be attained while maintaining best ever values in the beam quality, including final relative energy spread (<2.5x 10^-5 rms) and transverse emittance (<1 mm-mrad norm. rms). The difficulties related to space charge emerge in the 10m long, 100 keV section of the CEBAF injector during initial beam production and acceleration. A series of changes were introduced in the CEBAF injector to meet the new requirements, including changes in the injector setup, adding new magnets, replacing lasers used for the photocathode and modifying typical laser parameters, stabilizing RF systems, and changes to standard operating procedures. In this paper, we will discuss all these modifications in some detail including the excellent agreement between the experimental results and detailed simulations. We will also present some of our operational results.

TUPLT165	A PARMELA Model of the CEBAF Injector valid over a Wide Range of Parameters	simulation, space-charge, emittance, electron	1515
	Y. Zhang, K. Beard, F.J. Benesch, Y.-C. Chao, A. Freyberger, J.M. Grames, R. Kazimi, G.A. Krafft, R. Li, L. Merminga, M. Poelker, M. Tiefenback, B.C. Yunn Jefferson Lab, Newport News, Virginia
	A pre-existing PARMELA model of the CEBAF injector has been recently verified using machine survey data and also extended to 60 MeV region. The initial distribution and temperature of an electron bunch are determined by the photocathode laser spot size and emittance measurements. The improved injector model has been used for extensive computer simulations of the simultaneous delivery of the Hall A beam required for a hypernuclear experiment, and the Hall C beam, required for a parity experiment. The Hall C beam requires a factor of 6 higher bunch charge than the Hall A beam, with significantly increased space charge effects, while the Hall A beam has an exceedingly stringent energy spread requirement of 2.5x 10^-5 rms. Measurements of the beam properties of both beams at several energies (100 keV, 500 keV, 5 MeV, 60 MeV) and several values of the bunch charge were performed using the standard quad-wire scanner technique. Comparisons of simulated particle transmission rate, longitudinal beam size, transverse emittance and twiss parameters, and energy spread against experimental data yield reasonably good agreement. The model is being used for searching for optimal setting of the CEBAF injector.

WEPKF012	LHC Dipole Axis, Spool Piece Alignment and Field Angle in Warm and Cold Conditions	dipole, alignment, quadrupole, sextupole	1618
	M. Coccoli, M. Buzio, J. Garcia Perez CERN, Geneva
	The installation and commissioning of the LHC dipoles requires the knowledge of the magnetic axis and of the spool piece corrector alignment at the operating conditions. The installation is based at present on the use of geometric information derived from mechanical measurements performed in warm conditions, with the assumption that the geometric and magnetic axis are coincident. Any discrepancies between mechanical and magnetic axis and unforeseen geometry variations from ambient to cold operating temperature can introuduce important uncertaintes in the prediction of the alignment at operational conditions. Such prediction is studied through correlations between measurements performed at room and liquid helium temperature. A statistic analysis of the measurement data available is presented showing uncertainties on the correctors alignment. They are compared with beam-based specifications of the positioning of the spool piece.

WEPKF016	Instrumental Uncertainty in Measuring the Geometry of the LHC Main Dipoles.	simulation, dipole, extraction, alignment	1627
	M. La China, G. Gubello, W. Scandale CERN, Geneva
	In the Large Hadron Collider 1232 superconducting dipoles will bend the two 7 TeV energy beams along a 27 km-circumference trajectory. The series production (assigned to three European firms) will require a well-defined procedure to check, in every magnet, the respect of the dimensional specifications. To verify the tolerances of few tenths of millimeter over the 15-meter length in each cold mass, a laser tracker is necessarily used. To access the two beam apertures and to increase the measurement accuracies, the laser tracker is placed in different stations around the dipole defining a 'multi-station measuring procedure'. The noise affecting all the data taken so far suggested a careful analysis of the procedure itself. Through the computer modeling (based on a Monte Carlo algorithm), the statistical error was quantified and compared to the experimental error. From this comparison the critical aspects of low accuracy rooted in the multi-station procedure were better understood, allowing the optimization of the procedure itself for the forthcoming series production.

WEPKF026	Kicker Pulser with High Stability for the BESSY FEL	kicker, power-supply, extraction, electron	1654
	J. Feikes, O. Dressler, J. Kuszynski BESSY GmbH, Berlin
	In the BESSY FEL design a kicker system is forseen to extract electron bunches from the main LINAC into two FEL beam lines, beside the straigth main beamline. Sine half wave pulsers with a repetion rate of up to 1 kHz and modest pulse currents of 120A will be used. To receive the maximum FEL gain, it is crucial, that the extracted bunches enter well centered into the undulators. Hence, the extraction demands for very high short-term stability of the magnetic field (shot to shot). A kicker pulse amplitude with a relative amplitude jitter smaller than 5* 10^-5 would be tolerable ?more than one order smaller than the jitter of conventional BESSY II kicker systems in use. A new highly stable semiconductor based kicker pulser prototype was designed, built and tested at BESSY. It was shown that the stability of the pulse current fulfills the FEL requirements. The pulser design, its layout and the corresponding pulse current jitter measurements are presented.

WEPLT019	Towards a Unified General Purpose CAD System at CERN	feedback	1864
	T. Hakulinen, C. Andrews, B. Feral, P.-O. Friman, M. Mottier, T. Pettersson, C. Sorensen, E. Van Uytvinck CERN, Geneva
	Several different CAD systems are in use at CERN today. Most of the 3D design work for the LHC is being done using Euclid from MDTVision. For 2D design work AutoCAD is widely used. Also, various special design tools exist for tasks such as electrical design and schematics. Even though LHC design will be finished with Euclid, it has been clear since several years that a new 3D CAD system will be needed in the future. For this reason CERN carried out a comparison between the currently available 3D CAD software using a set of selection criteria important for CERN. The selected system was CATIA from Dassault together with local data base system SmarTeam. The aim is to use CATIA as a multi-disciplinary general purpose CAD tool which could eventually replace almost all of the other CAD systems at CERN. For this purpose, CATIA and SmarTeam are being integrated with the existing CAD utilities and data base systems developed in-house. Pilot users are using the system for real designs and the digital mock-up features of CATIA are used for integration studies of LHC experiments. The feature list of CATIA and SmarTeam is impressive and experience with the software has so far been almost exclusively positive. This is promising for software with which CERN will likely have to live for the next 20 years or more.

WEPLT037	A J2EE Solution for Technical Infrastructure Monitoring at CERN	monitoring, controls, vacuum, collider	1912
	J. Stowisek, R.M. Martini, P. Sollander CERN, Geneva
	The Technical Infrastructure Monitoring project (TIM) will design and implement the future control system for CERN's technical infrastructure. The control system will be built using standard components including industrial PLCs, Java Enterprise Edition (J2EE) including Enterprise Java Beans and the Java Message Service and relational databases. This paper describes how these standard technologies are used to build a flexible, scalable, robust and reliable control system.

WEPLT061	Influence of Beam Tube Obstacles on the Emittance of the PITZ Photoinjector	emittance, simulation, cathode, diagnostics	1984
	S. Setzer, W. Ackermann, S. Schnepp, T. Weiland TEMF, Darmstadt
	For detailed analysis of space charge dominated beams inside an RF Photoinjector PIC-Codes like MAFIA TS2/3 can be used. While the interaction of particles with the sourrounding geometries are taken into account, the applicability of such codes is restricted due to simulation time and memory consumption as well as by numercial noise. Therefore only smaller sections of the whole injector can be calculated. On the other hand codes like ASTRA can be used to simulate the whole injector but no interaction between bunch and geometry is included. To make use of the individual advantages of each code discribed above an interface for bidirectional bunch exchange between the two programs has been implemented. This approach allows for applying the right simulation method depending on the physical effects under investigation. To demonstrate the importance of such an approach the results of detailed numerical studies of the impact of beam tube obstacles like the laser mirror on the achievable emittance of the PITZ RF Photoinjector further downstream will be presented.

WEPLT100	Planar Electron Sources and the Electron Trap ELTRAP	electron, cathode, plasma, injection	2083
	M. Cavenago INFN/LNL, Legnaro, Padova G. Bettega, F. Cavaliere, A. Illiberi, R. Pozzoli, M. Romé, L. Serafini INFN-Milano, Milano
	Filamentation and other space charge effects (both transverse and longitudinal) of intense electron beams, found for example in rf photoinjectors (beam energy 1 MeV, current 100 A), are easily studied in small voltage traps and drift channels (0.01-10 kV), keeping the same perveance order. A suitable Malmberg-Penning trap, named ELTRAP, installed and operated at the University of Milan, is briefly described; trap length ranges from 10 cm to 1 m; an uniform magnetic field confines electron radially. Several experimental regimes were investigated with the internal CW planar electron source: plasma, beam-plasma, beam, depending on the injection/extraction method chosen. Evolution of electron vortices and virtual cathode formation is documented; analogy with meteorologic and astrophysical plasma is discussed. Upgrading with an external laser pulsed electron source is in course. Larger planar sources are also under construction. (Main classification 4: Beam Dynamics and Electro-magnetic Fields; D03 High Intensity, Incoherent Instabilities, Space Charge, Halos, Cooling; Other classification 8: Low and Intermediate Energy Accelerators and Sources; T12 Beam Injection/Extraction and Transport; T02 Lepton sources)

WEPLT116	Lattice Design and Cooling Simulation at S-LSR	electron, ion, lattice, quadrupole	2122
	T. Shirai, H. Fadil, S. Fujimoto, M. Ikegami, A. Noda, M. Tanabe, H. Tongu Kyoto ICR, Uji, Kyoto T. Fujimoto, H. Fujiwara, K. Noda, S. Shibuya, T. Takeuchi NIRS, Chiba-shi M. Grieser MPI-K, Heidelberg H. Okamoto, Y. Yuri HU/AdSM, Higashi-Hiroshima E. Syresin JINR, Dubna, Moscow Region
	A compact ion cooler ring, S-LSR is under construction in Kyoto University. The circumference is 22.557 m and the maximum magnetic rigidity is 1 Tm. One of the important roles of S-LSR is a test bed to examine the lowest temperature limit of the ion beams using cooling techniques. The ultimate case is a crystalline one. The ring optics of S-LSR has a high super periodicity and a low phase advance to reduce the beam heating from the lattice structure. S-LSR has an electron beam cooling device and a laser cooling system for Mg. The simulation results show the possible limit of the ion beam temperature and the dependence on the operating betatron tunes.

WEPLT138	Laser Cooling of Electron Bunches in Compton Storage Rings	synchrotron, emittance, electron, damping	2161
	E.V. Bulyak NSC/KIPT, Kharkov
	Self-consistent dynamics of a bunch circulating in the Compton storage ring has been studied analytically. Disturbances from both the synchrotron and Compton radiations were taken into account. The emittances in laser-dominated rings (where the synchrotron energy losses are much smaller then the Compton ones) were evaluated. The resultant emittances (synchrotrons plus Comptons) were compared with the synchrotrons. As were shown, the longitudinal degree of freedom is heated up due to Compton scattering. Almost the same conclusion is valid for the vertical uncoupled betatron emittance. Since it is impossible in principle to get zero dispersion in the banding magnets, the radial emittance almost always cooling down by laser. Therefore in practical cases of coupled transverse oscillations with the horizontal emittance determining the vertical one, the laser will cool down the transverse degrees of freedom.

WEPLT140	New Abilities of Computer Code DeCA	photon, scattering, electron, simulation	2164
	P. Gladkikh, A.Y. Zelinsky NSC/KIPT, Kharkov
	In the paper the status and new abilities of computer code package DeCA (Design of Cyclic Acclerators) are described. The main effort of the code developers were made to creation of software capable to simulate intrabeam scattering effect and Compton scattering. In addition modules for calculation of the second order dispersion and momentum compaction factor were developed.

WEPLT156	Suppression of Microbunching Instability in the Linac Coherent Light Source	electron, undulator, linac, simulation	2206
	Z. Huang, P. Emma, C. Limborg-Deprey, G.V. Stupakov, J.J. Welch, J. Wu SLAC, Menlo Park, California M. Borland ANL/APS, Argonne, Illinois
	A microbunching instability driven by longitudinal space charge, coherent synchrotron radiation and linac wakefields is studied for the linac coherent light source (LCLS) accelerator system. Since the uncorrelated (local) energy spread of electron beams generated from a photocathode rf gun is very small, the microbunching gain may be large enough to significantly amplify shot noise fluctuations of the electron beam. The uncorrelated energy spread can be increased by an order of magnitude without degrading the free-electron laser performance to provide strong Landau damping against the instability. We study different damping options in the LCLS and discuss an effective laser heater to minimize the impacts of the instability on the quality of the electron beam.

WEPLT171	Rotating Electromagnetic Field Trap for High Temperature Plasma and Charge Confinement	electron, quadrupole, electromagnetic-fields, plasma	2230
	V.V. Danilov ORNL/SNS, Oak Ridge, Tennessee
	This paper demonstrates that there exists a special combination of oscillating electromagnetic fields capable of trapping ultra high charge densities. Trapped particles undergo stable motion when their frequencies of oscillation are much higher than that of the ocillating field. Contrary to conventional electromagnetic traps, the motion in this dynamic trap is stable for arbitrarily high electromagnetic field amplitudes. This, in turn, leads to the possibility of using enormous electric and magnetic fields from RF or laser sources to confine dense ultrahigh temperature plasmas and particle beams.

THYCH01	Issues and Challenges for Short Pulse Radiation Production	electron, photon, radiation, linac	225
	P. Emma SLAC/ARDA, Menlo Park, California
	A new generation of light sources are being planned at many locations, pushing the frontiers of brightness, wavelength, and peak power well beyond existing 3rd generation sources. In addition to these large scale improvements there is great interest in extremely short duration pulses into the femtosecond and sub-femtosecond regime. Collective electron bunch instabilities at these scales are severe, especially in consideration of the high-brightness electron bunch requirements. Several new schemes propose very short radiation pulses generated with moderate electron bunch lengths. Such schemes include radiation pulse compression, differential bunch spoiling, staged high-gain harmonic generation, and selective pulse seeding schemes. We will describe a few of these ideas and address some of the electron bunch length limitations, highlighting recent measurements at the Sub-Picosecond Pulse Source (SPPS) at SLAC where <100-fs electron and x-ray pulses are now available.
	Video of talk
	Transparencies

THOALH01	Bunch Length Measurements at the SLS Linac using Electro-optical Techniques	linac, radiation, electron, radio-frequency	253
	A. Winter, M. Tonutti RWTH, Aachen S. Casalbuoni, P. Schmüser, S. Simrock, B. Steffen DESY, Hamburg T. Korhonen, T. Schilcher, V. Schlott, H. Sigg, D. Suetterlin PSI, Villigen
	The temporal profile of the electron bunches in the SLS Linac will be determined by means of electro-optical techniques. A mode locked Ti:Sa Laser with 15 fs pulse width is used for coincidence measurements between the laser pulse and the coherent transition radiation (CTR) generated by short electron bunches. Synchronization accuracy of 100 fs rms between the 3 GHz Linac RF and the 81 MHz repetition rate of the laser was achieved, which is important for the optimum time resolution of the applied electro-optical sampling technique. Likewise, a mode locked Nd:YAG laser with 400 ps long pulses will be used for electro-optical autocorrelation measurements between the CTR and the laser pulses. This alternative technique promises single shot capability and requires much relaxed synchronization stability between laser and electron beam.
	Video of talk
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THYLH01	Beam Diagnostics at the VUV-FEL Facility	radiation, electron, diagnostics, photon	262
	J. Feldhaus, D. Noelle DESY, Hamburg
	The free electron laser (FEL) at the TESLA Test facility at DESY will be the first FEL user facility for VUV and soft X-ray radiation down to 6 nm wavelength, the commissioning starts in summer 2004. Commissioning as well as stable FEL operation require a combination of different diagnostic tools for measuring both electron and photon beam parameters, including the full phase space distribution of the bunch charge, exact timing with sub-picosecond resolution, electron and photon beam overlap along the undulator, radiation beam position in the user area 50-70 m behind the undulator, intensity and spectral distribution of the radiation pulses and others. Much effort has been put in the development of instrumentation for measuring the longitudinal bunch charge distribution, for controlling the electron beam orbit along the undulator, and for online monitoring the radiation intensity, position and spectral distribution. This contribution gives an overview of the complete electron and photon beam diagnostics of the FEL facility and focuses particularly on the instrumentation which is crucial or specific for the FEL operation.
	Video of talk
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THOBLH02	Ultrafast Compton Scattering X-Ray Source Development at LLNL	electron, photon, scattering, interaction-region	270
	F.V. Hartemann, S. Anderson, C.P.J. Barty, S.M. Betts, R. Booth, J. Brown, K. Crane, R.R. Cross, D.N. Fittinghoff, D. Gibson, E.P. Hartouni, J. Kuba, G.P. Le Sage, D.R. Slaughter, P.T. Springer, A. Tremaine, A.J. Wootton LLNL, Livermore, California J. Rosenzweig UCLA, Los Angeles, California
	The LLNL PLEIADES (Picosecond Laser-Electron Inter-Action for the Dynamical Evaluation of Structures) facility is now operating between 30 and 80 keV, and produces > 5 x 10⁶ photons per shot at 10 Hz. This important milestone offers a new opportunity to develop laser-driven, compact, tunable x-ray sources for critical applications such as NIF diagnostics, time-resolved material studies, and advanced biomedical imaging. Initial x-rays were captured with a CCD using a CsI scintillator; the photon energy was measured at approximately 70 keV, and the observed spectral and angular distributions found to agree very well with three-dimensional codes. The electron beam was focused to 30 um rms, at 54 MeV, with 250 pC of charge, a relative energy spread of 0.2%, and a normalized emittance of 10 mm.mrad. Optimization of the x-ray dose is currently underway, with the goal of reaching 10⁷ photons per shot and a peak brightness approaching 10¹⁷ photons/mm2/mrad2/s/0.1%bandwidth. High-Z K-edge radiographs have been demonstrated, as well as diffraction using highly-ordered pyrolytic graphite crystals. Nonlinear scattering experiments, using a tightly focused laser spot will also be discussed, as well as plans to develop a source capable of reaching 1% conversion efficiency from the electron beam kinetic energy into x-rays, and ultrafast diffraction experiments.
	Video of talk
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THPKF013	Terahertz Diagnostics for the Femtosecond X-ray Source at BESSY	electron, radiation, dipole, undulator	2284
	K. Holldack, S. Khan, R. Mitzner, T. Quast, G. Wustefeld BESSY GmbH, Berlin
	A longitudinal electron density modulation caused by femtoslicing in a storage ring is accompanied by a strong broad band coherent THz-light emission between 0.3 and 10 THz at certain synchrotron radiation emitting devices downstream of the interaction region. A technique to use the THz signal for the control of the overlap of laser and electron bunch using fast infrared bolometers is described. A new dedicated THz extraction port at a bending magnet as well as a spectroscopic setup based on a Martin Puplett spectrometer will be commissioned in May 2004 together with the new femtoslicing source at BESSY. * A. Zholentz, M. Zoloterev, PRL 76/1996, 912** H.-J. Baecker et al., these proceedings

THPKF014	Status of the BESSY II Femtosecond X-ray Source	electron, radiation, storage-ring, wiggler	2287
	S. Khan, H.-J. Baecker, J. Bahrdt, H.A. Duerr, V. Duerr, W. Eberhardt, A. Gaupp, K. Godehusen, K. Holldack, E. Jaeschke, T. Kachel, D. Krämer, R. Mitzner, M. Neeb, W.B. Peatman, T. Quast, G. Reichardt, M.-M. Richter, M. Scheer, O. Schwarzkopf, F. Senf, G. Wustefeld BESSY GmbH, Berlin I. Hertel, F. Noack, W. Sandner, I. Will, N. Zhavarnokov MBI, Berlin
	At the BESSY II storage ring, work is in progress to produce X-ray pulses with 50 fs (fwhm) duration and tunable energy and polarization by "femtoslicing" [].This work includes extensive alterations to the storage ring (one new and one modified undulator, both in the same straight section, three additional dipole magnets, a new IR beamline, and nine meters of new vacuum vessels) and to two beamlines (relocation and new optical designs), as well as the installation of a femtosecond Ti:sapphire laser system. Commissioning is planned for May 2004. This paper reviews the principles and technical implementation of the new femtosecond X-ray source, and reports the status of the project. A. Zholentz, M. Zoloterev, Phys.Rev.Lett. 76 (1996), 912

THPKF029	Femto-second Electron Beam Slicing Project at SOLEIL	electron, photon, separation-scheme, undulator	2332
	O.V. Chubar, M. Idir, M.-P. Level, A. Loulergue, T. Moreno, A. Nadji, L.S. Nadolski, F. Polack SOLEIL, Gif-sur-Yvette
	The goal of the slicing project at SOLEIL is to provide short (50-100 fs) soft and hard X-rays pulses. The principle is based on the technique demonstrated earlier at ALS. In our case, the naturally suitable phase advances and the horizontal distributed dispersion enable the sliced pulse to be used on several consecutive straight sections. Further separation between the core and the sliced electron beams is obtained by increasing the effective horizontal dispersion using a chicane bracketing the modulator. In the hard X-rays case, the photon beams are separated spatially using a simple slit in a pinhole-camera type configuration while a mixed spatial-angular separation is chosen for the soft X-rays case. This minimizes the amount of parasitic core radiation scattered from the surface of the first focusing mirror. We will first describe the proposed scheme, the impact on the machine and some other issues. Then, photon optics calculation is presented. This takes into account the SOLEIL magnet lattice, realistic parameters of a femto-second laser, peculiarities of spectral distributions of undulator radiation and its diffraction in the range of intensities covering several orders of magnitude.

THPKF039	Study of Photo-cathode RF Gun for a High Brightness Electron Beam	gun, cathode, electron, injection	2362
	Y. Yamazaki JNC/OEC, Ibaraki-ken S. Araki, H. Hayano, M. Kuriki, T. Muto, N. Terunuma, J. Urakawa KEK, Ibaraki M.K. Fukuda, K. Hirano, M. Nomura, M. Takano NIRS, Chiba-shi
	We are going to develop a compact high-brightness electron beam system to adopt industrial and medical applications. A multi-bunch photo-cathode RF gun has been developed to generate 100 bunches beam with 2.8ns spacing and 5nC charge per bunch. We will report details of the development, especially photo-cathode production and emission characteristics from cathode by the laser.

THPKF040	Development of a Femtosecond Pulse Radiolysis for Reaction Analysis in Nano-space	electron, ion, linac, gun	2365
	Y. Yoshida, T. Kozawa, S. Tagawa, J. Yang ISIR, Osaka
	A new femtosecond pulseradiolysis system was developed in Osaka University for the study of radiation-induced ultrafast physical and chemical reactions in femtosecond time regions. In the pulseradiolysis system, a femtosecond electron beam produced by a photocathode RF gun is used as an irradiation source, while a mode-locked Ti:Sapphire femtosecond laser was used as a probe light source. A time jitter between the electron pulse and the femtosecond laser was compensated by a jitter compensation technique used a femtosecond streak camera. An oblique incidence of the probe light is considered in the system to reduce the degradation of velocity difference between the electron and the laser light in samples. A time resolution of <100 fs is expected in the pulse radiolysis system for the analysis of utrafast physical and chemical reactions in nano-space.

THPKF059	Adaption of an RF-gun from Thermionic to Photo Cathode	cathode, gun, injection, electron	2397
	S. Werin, M. Berglund, M. Brandin, T. Hansen MAX-lab, Lund
	The current electron source for the injector at MAX-lab is a thermionic RF-gun. This gun produces a several ns long pulse with a significant beamloading. To allow for ?few bucket? operation and emittance reduction the gun will be adapted for operation with a ns laser system. The system to be installed during the spring 2004 is a 3 or 4th harmonic injection seeded Nd:YAG laser. The thermionic BaO cathode already in use will be used at a temperature just below thermal emission where a quantum efficiency of around 1* 10^-4 is expected.

THPKF063	Parameters of X-ray Radiation Emitted by Compton Sources	electron, scattering, collimation, photon	2409
	E.V. Bulyak, V. Skomorokhov NSC/KIPT, Kharkov
	Presented are results of analytical study on X–ray beam parameters generated in the Compton storage rings. A model with the given circulating electron bunch parameters and the laser splash as well is considered. For this model, the total yield of x–ray quanta is derived as a function of the crossing angle and geometric dimensions of both the bunch and splash. Also spectral characteristics of emitting x–ray beam are evaluated with account for the collimating conditions and both the angular and energy spreads in the bunch. As is shown the width of x–ray energy spectrum is narrowest for the x-ray beam collimated along the bunch orbit. With increasing the scattering angle (with respect to the bunch orbit) the spectrum of emitting quanta is widening. Problems of x-ray beam generation with required energy and brightness with the Compton storage rings are discussed.

THPKF064	Status of Kharkov X-ray Generator based on Compton Scattering NESTOR	storage-ring, quadrupole, injection, electron	2412
	A.Y. Zelinsky, V.P. Androsov, E.V. Bulyak, I.V. Drebot, P. Gladkikh, V.A. Grevtsev, V.A. Ivashchenko, I.M. Karnaukhov, V. Lapshin, V. Markov, N.I. Mocheshnikov, A. Mytsykov, F.A. Peev, A.V. Rezaev, A.A. Shcherbakov, V.L. Skirda, V.A. Skomorokhov, Y.N. Telegin, V.I. Trotsenko NSC/KIPT, Kharkov A. Agafonov, A.N. Lebedev LPI, Moscow J.I.M. Botman TUE, Eindhoven T.R. Tatchyn SLAC/SSRL, Menlo Park, California
	Nowadays the sources of the X-rays based on a storage ring with low beam energy and Compton scattering of intense laser beam are under development in several laboratories. In the paper the state-of-art in development and construction of cooperative project of a Kharkov advanced X-ray source NESTOR based on electron storage ring with beam energy 43 - 225 MeV and Nd:YAG laser is described. The layout of the facility is presented and main results and constructing timetable are described. The designed lattice includes 4 dipole magnets with combined focusing functions, 20 quadrupole magnets and 19 sextupoles with octupole component of magnetic field. At the present time a set of quadrupole magnet is under manufacturing and bending magnet reconstruction is going on. The main parameters of developed vacuum system providing residual gas pressure in the storage ring vacuum chamber up to 10-9 torr are presented along with testing measurement at NSC KIPT vacuum bench. The facility is going to be in operation in the middle of 2006 and generated X-rays flux is expexted to be of about 10¹³ phot/s.

THPKF073	CIRCE, the Coherent InfraRed CEnter at the ALS	radiation, storage-ring, synchrotron, synchrotron-radiation	2436
	J.M. Byrd, S. De Santis, J.-Y. Jung, M.C. Martin, W.R. McKinney, D.V. Munson, H. Nishimura, D. Robin, F. Sannibale, R.D. Schlueter, M. Venturini, W. Wan, M.S. Zolotorev LBNL, Berkeley, California
	CIRCE (Coherent InfraRed Center) is a new electron storage ring to be built at the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory (LBNL). The ring design is optimized for the generation of coherent synchrotron radiation (CSR) in the terahertz frequency range. CIRCE operation includes three possible modes: ultra stable CSR, femtosecond laser slicing CSR and broadband SASE. CSR will allow CIRCE to produce an extremely high flux in the terahertz frequency region. The many orders of magnitude increase in the intensity is the basis of our project and enables new kinds of science. The characteristics of CIRCE and of the different modes of operation are described in this paper.

THPKF075	LUX - A Recirculating Linac-based Facility for Ultrafast X-ray Science	linac, electron, undulator, radiation	2439
	J.N. Corlett, W.A. Barletta, S. De Santis, L.R. Doolittle, W. Fawley, P.A. Heimann, S.R. Leone, D. Li, S.M. Lidia, G. Penn, A. Ratti, M. Reinsch, R.W. Schoenlein, J.W. Staples, G.D. Stover, S.P. Virostek, W. Wan, R. Wells, R.B. Wilcox, A. Wolski, J.S. Wurtele, A. Zholents LBNL, Berkeley, California
	We present design concepts for LUX - a proposed source of ultra-fast synchrotron radiation pulses based on a recirculating superconducting linac. The source produces high-flux VUV-x-ray pulses with duration of 100 fs or less at a 10 kHz repetition rate, optimized for the study of ultra-fast dynamics across many fields of science. Cascaded harmonic generation in free-electron lasers (FEL's) produces coherent radiation in the VUV-soft x-ray regime, and a specialized technique is used to compress spontaneous emission for ultra-short-pulse photon production in the 1 - 10 keV range. High-brightness electron bunches of 2-3 mm-mrad emittance at 1 nC charge in 30 ps duration are produced in an rf photocathode gun and compressed to 3 ps duration following an injector linac, and recirculated three times through a 1 GeV main linac. In each return path, harmonic cascades are inserted to produce seeded FEL radiation in selected photon energy ranges from approximately 20 eV with a single stage of harmonic generation, to 1 keV with a four-stage cascade. The lattice is designed to minimize emittance growth from effects such as coherent synchrotron radiation (CSR), and to propagate electron beams carrying nm-scale density modulation in the final stages of cascaded harmonic generation. Synchronization of tens of femtoseconds is achieved by use of an optical master oscillator distributing timing signals over actively stabilized fiber, and generation of rf signals from the optical master oscillator. We describe technical developments in key areas including injection from a high repetition rate rf photocathode gun, lattice design, UV and soft x-ray production by high-gain harmonic generation, a kicker design for rapid transfer of the electron beam between radiator beamlines, lasers systems concepts, and synchronization between experimental pump lasers and the x-ray pulse.

THPKF077	A Fiber Optic Synchronization System for LUX	feedback, controls, linac, undulator	2445
	R.B. Wilcox, L.R. Doolittle, J.W. Staples LBNL, Berkeley, California
	The proposed LUX femtotsecond light source will support pump-probe experiments that will need to synchronize laser light pulses with electron-beam-generated X-ray pulses to less than 50fs at the experimenter endstations. To synchronize multiple endstation lasers with the X-ray pulse, we are developing a fiber-distributed optical timing network. A high stability clock signal from a modelocked laser is distributed via fiber to RF cavities (controlling X-ray probe pulse timing) and modelocked lasers at endstations (controlling pump pulse timing). The superconducting cavities are actively locked to the optical clock phase. Most of the RF timing error is contained within a 10kHz bandwidth, so these errors and any others affecting X-ray pulse timing (such as RF gun phase) can be detected and transmitted digitally to correct laser timing at the endstations. The lasers? timing jitter is limited to low frequency, and thus they will follow the controls (clock plus error correction) without adding much wideband error. Time delay through the fibers will be stabilized by comparing a retroreflected pulse from the experimenter endstation end with a reference pulse from the sending end, and actively controlling the fiber length. Numerical simulations and initial synchronization experimental results will be presented.

THPKF078	Coherent Infrared Radiation from the ALS Generated via Femtosecond Laser Modulation of the Electron Beam	electron, wiggler, radiation, lattice	2448
	A. Zholents, J.M. Byrd, Z. Hao, M.C. Martin, D. Robin, F. Sannibale, R.W. Schoenlein, M. Venturini, M.S. Zolotorev LBNL, Berkeley, California
	Interaction of an electron beam with a femtosecond laser pulse co-propagating through a wiggler at the ALS produces significant modulation of the electron energies within a short ~100 fs slice of the electron bunch. Subsequent propagation of the energy-modulated bunch around the storage ring results in an appearance of a local temporal modulation of the electron density (micro-bunching) due to the dispersion of electron trajectories. The temporal width of this perturbation evolves as the electron bunch propagates around the ring. The shortest modulation, ~50 microns, appears in the ALS sector immediately following the wiggler magnet, and stretches to ~ 500 microns following propagation over 2/3 of a storage ring orbit. The modulated electron bunch emits single-cycle pulses of temporally and spatially coherent infrared light which are automatically synchronized to the laser pulses. The intensity and spectra of the infrared light were measured in two locations in the ring indicated above and were found to be in good agreement with analytical calculations. Ultra-short pulses of coherent infrared radiation are presently used for a fine tuning the laser ? electron beam interaction for generating femtosecond x-ray pulses.

THPKF084	Emerging Concepts, Technologies and Opportunities for Mezzo-scale Terahertz and Infrared Facilities	electron, radiation, linac, synchrotron	2454
	S. Chattopadhyay, S.T. Corneliussen, G.P. Williams Jefferson Lab, Newport News, Virginia
	Recent advances in particle beam, laser and radiofrequency technologies, combined with innovative concepts and techniques such as energy recovery, coherent synchrotron radiation-induced bunching, laser-particle beam scattering, ultrashort pulse slicing, cw high current and brightness phtoinjectors, ultrafast laser switching and compact engineered end products have opened up new opportunities and vistas in terahertz/infrared radiation sources not available before. Such sources would complement the high energy short wavelength x-ray sources in that they will allow us to probe collective processes and their ?function? in complex systems and materials, in a fashion complementary to probing structure via x-rays. We will outline and give examples of both the scientific reach of such radiation sources as well as examples of a few conceived facilities and techniques worldwide spanning a diversity of spectral, coherence, brightness and application ranges in the long wavelength. Such facilities fall in the category of mezzo-scale facilities, bracketed by table top lasers on one hand and large scale synchrotron radiation sources on the other and offer very unique and directed advances in a few key areas in life, materials, imaging, instrumentation and communication sciences.

THPLT026	Beam Profile Measurements at PETRA with the Laserwire Compton Scattering Monitor	photon, positron, background, collider	2529
	T. Kamps BESSY GmbH, Berlin K. Balewski, H.-C. Lewin, S. Schreiber, K. Wittenburg DESY, Hamburg G.A. Blair, G. Boorman, J. Carter, F. Poirier Royal Holloway, University of London, Surrey S.T. Boogert UCL, London T. Lefevre CERN, Geneva
	The vertical beam profile at the PETRA positron storage ring has been measured using a laserwire scanner. A laserwire monitor is a device which can measure high brilliant beam profiles by scanning a finely focused laser beam non-invasively across the charged particle beam. Evaluation of the Compton scattered photon flux as a function of the laser beam position yields the transverse beam profile. The aim of the experiment at PETRA is to obtain the profile of the positron beam at several GeV energy and several nC bunch charge. Key elements of laserwire systems are currently being studied and are described in this paper such as laser beam optics, a fast scanning system and a photon calorimeter. Results are presented from positron beam profile scans using orbit bumps and a fast scanning scheme.

THPLT027	Optical Transition Radiation Based Beam Diagnostics at the BESSY Synchrotron Radiation Source and FEL Accelerators	electron, radiation, photon, linac	2532
	T. Kamps, K. Holldack, P. Kuske BESSY GmbH, Berlin
	Optical Transition Radiation (OTR) based diagnostics tools are widely used in linear accelerators to measure beam parameters like transverse beam size and emittance. Design ideas for OTR stations in the linac section of the BESSY FEL facility are presented. Several key components will be tested in the transfer lines of the BESSY storage ring. Furthermore a novel type of OTR monitor is introduced which enables the measurement of the transverse overlap of seed laser and electron beam in the undulator sections of the linac based FEL facility. Here a special radiator screen will be used allowing simultaneous imaging of both beams in the same optical readout channel.

THPLT034	Implementation of Higher Order Moments for Beam Dynamics Simulation with the V-Code	simulation, space-charge, gun, emittance	2553
	W. Ackermann, T. Weiland TEMF, Darmstadt
	Based on the moment approach V-Code is implemented to simulate charged particle beam dynamics in linear accelerators. Its main aim is to perform elementary studies in those cases when the beam can be considered as a whole and thus making the motion of individual particles negligible in the overall view. Therefore an ensemble of particles can be well described by the moments of its phase-space distribution and the regarded order influences naturally the achievable accuracy as well as the computational effort. Since the well known moment equations generally are not closed, a technique to limit the number of involved moments has to be applied. So far all moments up to the second order have been considered whereas higher order moments are truncated. As a further step towards higher accuracy the influence of higher order moments has to be investigated. For this reason additional third-order equations are implemented into the V-Code and the achieved results are compared with previous second-order-based ones as well as with higher order approximations.

THPLT044	Measurement of the Transverse Coherence of the TTF Free Electron Laser	undulator, electron, radiation, free-electron-laser	2580
	R. Ischebeck, M. Tonutti RWTH, Aachen J. Feldhaus, E. Saldin, E. Schneidmiller, K. Tiedtke, R. Treusch DESY, Hamburg C. Gerth CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire P. Schmüser Uni HH, Hamburg M.V. Yurkov JINR, Dubna, Moscow Region
	The transverse coherence is important for many applications of a free electron laser (FEL). It depends on the inner structure of the electron bunch in the undulator, which is difficult to measure. It is therefore essential to determine the coherence properties of the FEL radiation directly. The coherence of the vacuum ultraviolet FEL at the TESLA Test Facility has been measured by recording the diffraction pattern of a double slit and measuring the visibility of the interference fringes. The experimental near field diffraction pattern is compared with a numerical model, taking into account the formation of the FEL radiation, the Fresnel diffraction in the near field zone and effects of the experimental set-up. Diffraction patterns have been recorded at various undulator lengths to measure the evolution of the transverse coherence along the undulator. This is compared to the expected evolution of the transverse radiation modes.

THPLT061	Development of a Multibunch Photo-cathode RF Gun System	gun, cathode, injection, electron	2628
	J. Urakawa, M. Akemoto, S. Araki, H. Hayano, M. Kuriki, T. Muto, N. Terunuma, Y. Yamazaki KEK, Ibaraki M.K. Fukuda, K. Hirano, M. Nomura, M. Takano NIRS, Chiba-shi
	A multibunch photo-cathode RF gun system has been developed as a electron source for the production of quasi-monoenergetic X-rays based on inverse Compton scattering. This system consists of a photocathode rf gun, a cathode system, a laser system, beam diagnostic sections, and beam dump line. The gun produces 100 bunches with a 2.8ns bunch spacing and 5nC bunch charge. We will report on the RF gun system with 4 bending dipoles of a chicane which makes the laser injection to the cathode with perpendicular angle possible.

THPLT064	Enhancement of Laser Power from a Mode Lock Laser with an Optical Cavity	resonance, electron, scattering, target	2637
	M. Nomura, K. Hirano, M. Takano NIRS, Chiba-shi S. Araki, Y. Higashi, T. Taniguchi, J. Urakawa, Y. Yamazaki KEK, Ibaraki Y. Honda, N. Sasao, K. Takezawa Kyoto University, Kyoto H. Sakai ISSP/SRL, Chiba
	We have developed a laser-wire beam monitor to measure a beam profile in the KEK/ATF damping ring. This monitor is based on the inverse Compton scattering with a thin wire of the laser. The laser-wire is produced with a Fabry-Perot optical cavity in which laser power from a CW laser is stored and enhanced up to 1000 times. We have a plan to increase a gamma ray flux by using a pulsed laser instead of the CW laser. There are many applications for such a high flux gamma ray, e.g. medical use, transmutation and so on. We have done a test experiment of laser pulse stacking with a mode lock laser where wavelength is 1064 nm, repetition rate 357MHz, pulse width 7psec(FWHM) and a 42 cm long Fabry-Perot optical cavity. The experimental results show that laser power in the optical cavity can be enhanced by laser pulse stacking.

THPLT067	Development of Optical Diffraction Radiation Beam Size Diagnostics at KEK Accelerator Test Facility	target, diagnostics, radiation, photon	2646
	V. Karataev, H. Hayano, T. Muto, N. Terunuma, J. Urakawa KEK, Ibaraki R. Hamatsu TMU, Hatioji-shi,Tokyo A. Naumenko, A.P. Potylitsyn Tomsk Polytechnic University, Physical-Technical Department, Tomsk
	Extremely low emittance high current beam is required for the accelerators of the next generation such as linear collider to achieve a reasonable luminosity. However, up to now there is no a simple non-invasive technique for beam diagnostics. A method based on optical diffraction radiation (ODR) appearing when a charged particle passes through a slit between two semi-planes can be one of the promising approaches. The estimations show that it might be possible to measure the beam size as small as 10mcm for a single shot. For a test of the proposed technique we designed an experimental setup and installed it at the extraction line of the KEK-ATF (1.26GeV beam energy, 10¹⁰ e/bunch, rms beam size > 10mcm). The electron beam was moving through a 0.26mm wide slit. We have measured backward ODR angular distribution. We have observed the beam size effect on the measured quantities. The sensitivity to the beam size as small as 20mcm was achieved. However, some undesirable factors such as X-ray background, SR photons coming through the mask slit, big detector angular acceptance have to be reduced. In this case a few micrometers beam size could be measured.

THPLT076	Compact X-band (11.424 Ghz) Linac for Cancer Therapy	linac, electron, radiation, simulation	2670
	N.H. Quyet, K. Dobashi, F. Ebina, M. El-Ashmawy, A. Fukasawa, H. Iijima, H. Ogino, M. Uesaka UTNL, Ibaraki
	Since most of medical linacs use S-band frequency, so far, such linacs cannot fit to modern advanced treatment techniques such as Tomotherapy and Stereotactic radiotherapy, which allows physicians to locate the tumor position during treatment time and enable for beam modification based on the real time analysis. Therefore, a new generation of electron linac with the compact size, higher power, higher gradient that can supply the advanced requirements of cancer treatment has been become necessary. X-band frequencies range is one of the suitable frequencies range for design such linacs. In this paper we will describe the possible design of a X-band (11.424 GHz) medical linac with side-coupled standing wave structure which understudying in NERL, The University of Tokyo. We aim to couple the therapy machine to the Compton scattering tunable monochromatic X-ray inspection device to realize the simultaneous inspection/therapy. Detailed design and numerical results are presented.

THPLT080	Simulation Study of the Beam Loading Effect in an RF Gun	gun, simulation, emittance, beam-loading	2682
	K. Shinto, H. Hama, F. Hinode, A. Miyamoto, T. Tanaka LNS, Sendai
	Because of simple structure and apparatus, a thermionic rf gun has been considered to be employed in a new pre-injector for the future synchrotron radiation facility at Tohoku University. A 3-D beam simulation code for the rf gun using a Finite Difference Time Domain (FDTD) method to solve Maxwell's equations has been developed. In the rf gun, especially in case of the high beam current, electromagnetic fields induced by the electron beam are considered to affect beam characteristics such as beam emittance and energy spread. In the FDTD method, because the Maxwell?s equations are able to be solved including the term of current density of the charge, the electromagnetic fields produced by both the external rf power and the electron beam can be anticipated. Using the simulation code, beam loading effects on the characteristics of the electron beam extracted from the rf gun is investigated.

THPLT081	Present Status of Photo-cathode RF Gun System and its Applications at Waseda University	electron, gun, scattering, emittance	2685
	R. Kuroda, Y. Hama, K. Hidume, H. Hirama, M. Kawaguchi, N. Kudo, T. Kuribayasi, S. Minamiguchi, R. Moriyama, T. Saito, K. Sakaue, D. Ueyama, M. Washio RISE, Tokyo H. Hayano, J. Urakawa KEK, Ibaraki S. Kashiwagi ISIR, Osaka X.J. Wang BNL/NSLS, Upton, Long Island, New York
	High quality electron beam generation using photo-cathode rf gun system and its application have been developed at Waseda University. This system can generate about 4 MeV low emittance electron beam. This is applied for soft X-ray generation using laser Compton scattering and pulse radiolysis experiments based on the pump-probe technique. In case of the soft X-ray generation, Compton scattering experiments between about 4.2 MeV electron beam and Nd:YLF laser light (1047nm) is performed at 20 degrees interaction angle, so that about 300 eV soft X-ray is generated. In case of the pulse radiolysis experiments, the electron beam is used for the pump beam. The probe light is generated as white light by concentrating Nd:YLF laser light (1047nm) on the water cell. The measurement with about 30 ps (FWHM) time resolution of this system is demonstrated for the absorption of hydrated electrons. In this conference, we will present the experimental results, status of this system and future applications.

THPLT082	Beam Diagnostics for a Photocathode Rf-gun System	emittance, electron, simulation, space-charge	2688
	K. Sakaue, N. Kudo, R. Kuroda, M. Washio RISE, Tokyo H. Hayano, J. Urakawa KEK, Ibaraki S. Kashiwagi ISIR, Osaka
	Beam diagnostic systems for high quality electron beam emitted from photo-cathode rf gun have been developed. Beam characteristics such as bunch length and emittance measurements were performed at Waseda University. The bunch length was measured using an rms bunch length monitor based on beam spectrum analysis. The monitor is very useful as the non-destructive and conventional tool even for the relatively low energy electron beam around 5MeV. The measurement results of the rms bunch lengths using this monitor are in good agreement with the simulation results of PARMELA. However, it is not applicable for the measurement of longitudinal profile of the electron bunch, so that we have started the manufacturing of a deflection cavity, so-called RF-Kicker, to measure the longitudinal profiles of the bunch. The emittance has been measured by using a slit scan technique. By using double slit scan technique, emittance of 9mmmrad has been obtained. Though the value is not satisfactory small, we believe that much smaller emittance can be obtained by optimizing a laser profile. The measurement results and progress of rf gun at Waseda University will be presented at the conference.

THPLT086	High Temporal Resolution, Single-shot Electron Bunch-length Measurements	electron, undulator, coupling, monitoring	2700
	G. Berden, B. Redlich, A.F.G. Van der Meer FOM Rijnhuizen, Nieuwegein W.A. Gillespie, A. MacLeod UAD, Dundee S.P. Jamison Strathclyde University, Glasgow
	A new technique, combining the electro-optic detection of the Coulomb field of an electron bunch and the single-shot cross-correlation of optical pulses, is used to provide single-shot measurements of the shape and length of sub-picosecond electron bunches. As in our previous technique [I. Wilke et al., Phys. Rev. Lett. 88, 124801 (2002)], the electric field of the electron beam is encoded electro-optically on an optical pulse. Our earlier measurements, which involved encoding the time profile of the electron bunch on the spectrum of the optical pulse, showed electric field profiles with a FWHM of the order of 1.7 ps. The new method offers a much better time resolution since it avoids the significant measurement artifacts that can arise in our previous (spectral encoding technique due to the coupling between the temporal envelope and spectral content of the optical pulse. The cross-correlation technique has been applied to the measurement of electron bunches in FELIX, showing single bunches of around 500fs FWHM. The resolution is limited primarily by the electro-optic crystal thickness and the relatively low energy of the electrons (50 MeV).

THPLT142	A Laser-Based Longitudinal Density Monitor for the Large Hadron Collider	synchrotron, photon, monitoring, radiation	2789
	S. De Santis, J.F. Beche, J.M. Byrd, P. Datte, M. Placidi, V. Riot, R.W. Schoenlein, W.C. Turner, M.S. Zolotorev LBNL, Berkeley, California
	We report on the development of an instrument for the measurement of the longitudinal beam profile in the Large Hadron Collider. The technique used, which has been successfully demonstrated at the Advanced Light Source, mixes the synchrotron radiation with the light from a mode-locked solid state laser oscillator in a non-linear crystal. The up-converted radiation is then detected with a photomultiplier and processed to extract, store and display the required information. A 40 MHz laser, phase-locked to the ring radiofrequency system, with a 50 ps pulse length, would be suitable for measuring the dynamics of the core of each of the LHC 2808 bunches in a time span much shorter then the synchrotron period. The same instrument could also monitor the evolution of the bunch tails, the presence of untrapped particles and their diffusion into nominally empty RF buckets ("ghost bunches") as required by the CERN specifications. We also specify the required characteristics of the diagnostic light port in the LHC where our instrument would be installed. * Presently at Lawrence Livermore National Laboratory.

THPLT161	Compton X-ray Source	electron, gun, diagnostics, quadrupole	2837
	A.E. Vlieks, G. Caryotakis, D.W. Martin SLAC, Menlo Park, California C.A. DeStefano, W.J. Frederick, J.P. Heritage, N.C. Luhmann Jr. UCD, Davis, California
	In an effort to develop a monochromatic, tunable source of X-rays in the 20-85 KeV energy range, a 5.5 cell X-band RF gun has been designed and tested. Together with a 1.05 m high gradient accelerating structure (an NLC Collider component), this system generates and accelerates a beam of electrons to energies greater than 60 MeV. Monochromatic X-rays are generated, via the Compton Effect, through a head-on collision of this beam with a multi-terawatt laser beam.We are currently measuring and analyzing the performance of the complete system, including the energy, monochromaticity and emittance of the electron beam, the laser system performance and the X-ray flux from the beam-laser interaction. A tunable, monochromatic X-ray source has important medical applications.We will report on the latest results as well as describe the experimental setup, components and diagnostics.

THPLT167	SNS Laser Profile Monitor Progress	ion, electron, feedback, optics	2852
	W. Blokland, A.V. Aleksandrov, S. Assadi, C. Deibele, W. Grice, S. Henderson, T. Hunter, P. Ladd, G.R. Murdoch, J. Pogge, K. Potter, T.J. Shea, D. Stout ORNL/SNS, Oak Ridge, Tennessee V. Alexandrov BINP SB RAS, Protvino, Moscow Region
	SNS will use a Nd:YAG laser to measure transverse profiles in the 186-1000 MeV super-conducting LINAC (SCL) and Ti:Sapphire modelock laser to measure longitudinal profiles in the 2.5 MeV Medium Energy Beam Transport (MEBT). The laser beam is scanned across the H^- beam to photo-neutralize narrow slices. The liberated electrons are collected to provide a direct measurement of the transverse or longitudinal beam profile. We have successfully measured the transverse profile with a prototype system on the MEBT beam. The final SCL system uses an optical transport line that is installed alongside the 300 meter super-conducting LINAC to deliver laser light at 8 locations. Possible vibrations in the optical transport system can lead to inaccuracies in the profile measurement. We will use an active feedback system on a mirror to correct any vibration up to 2 KHz. In this paper we describe our vibration studies and vibration cancellation system as well as the progress in the design, installation and testing of various subsystems for both the transverse and the longitudinal profiles.