02 Synchrotron Light Sources and FELs
A06 Free Electron Lasers

Paper	Title	Page
MOYCA01	Status Report on the Commissioning of the Japanese XFEL at SPring-8	21
	H. Tanaka RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
	The Japanese XFEL at SPring-8, which was named SACLA (Spring-8 Angstrom Compact free electron LAser), was completed in FY2010. After RF full-power aging for about four months the beam commissioning of SACLA has been started since 21 February 2011. About one month later, in 23 March a design beam energy of 8 GeV was achieved and a spontaneous undulator radiation of 0.8 Angstrom was observed at the beam-line optical hutch by closing XFEL undulator gaps down to 5 mm in full-width. The beam commissioning has proceeded smoothly and since the middle of April we have entered to a tuning phase towards SASE lasing, which is at least one month ahead of schedule. This talk will report the beam commissioning overview of SACLA including SASE XFEL performance, key tuning-processes and critical issues for achieving the lasing.
	Slides MOYCA01 [37.840 MB]
TUZA02	sFLASH - Present Status and Commissioning Results	923
	V. Miltchev, S. Ackermann, A. Azima, J. Bödewadt, F. Curbis, M. Drescher, E. Hass, Th. Maltezopoulos, M. Mittenzwey, J. Rönsch-Schulenburg, J. Roßbach, R. Tarkeshian Uni HH, Hamburg, Germany H. Delsim-Hashemi, K. Honkavaara, T. Laarmann, H. Schlarb, S. Schreiber, M. Tischer DESY, Hamburg, Germany R. Ischebeck PSI, Villigen, Switzerland S. Khan DELTA, Dortmund, Germany
	The free-electron laser in Hamburg (FLASH) was previously being operated in the self-amplified spontaneous emission (SASE) mode, producing photons in the XUV wavelength range. Due to the start-up from noise the SASE-radiation consists of a number of uncorrelated modes, which results in a reduced coherence. One option to simultaneously improve both the coherence and the synchronisation between the FEL-pulse and an external laser is to operate FLASH as an amplifier of a seed produced using high harmonics generation (HHG). An experimental set-up - sFLASH, has been installed to test this concept for the wavelengths below 40 nm. The sFLASH installation took place during the planed FLASH shutdown in the winter of 2009/2010. The technical commissioning, which began in the spring of 2010, has been followed by seeded-FEL commissioning, FEL-characterisation and pilot experiments. In this contribution the present status and the sFLASH commissioning results will be discussed.
	Slides TUZA02 [4.125 MB]
WEXA01	Challenges of 4th Generation Light Sources	3798
	C. Pellegrini SLAC, Menlo Park, California, USA C. Pellegrini UCLA, Los Angeles, California, USA
	In the last few years Free Electron Lasers (FELs) have emerged as exceptionally exciting tools for new science. The results from FLASH (Hamburg) on biological imaging, LCLS (Stanford) which generated the first hard X-ray lasing and the projects proposed or in costruction around the world are rapidly moving the scientific community to the so called “fast science” which demands ultrashort pulses, fs synchronization, high brightness, high coherence X-rays. The basic SASE FEL process used so far converts energy jitter into jitter of the centralwavelength. Processes based on seeding and HGHG seem to offer a number of advantages in terms of bandwidth, coherence, stability and undulator length. This talk will present an overview of the 4th generation light sources, discussing the main challenges afforded in the construction of the operating facilities and considering the trends for the development of future facilities.
	Slides WEXA01 [10.640 MB]
THPC053	Shanghai Soft X-Ray Free Electron Laser Test Facility	3011
	Z.T. Zhao SINAP, Shanghai, People's Republic of China
	As a critical development step towards constructing a hard X-ray FEL in China, a soft X-ray FEL test facility (SXFEL) was proposed and will be constructed at the SSRF campus by a joint team of Institute of Tsinghua University and Shanghai Institute of Applied Physics. This test facility, based on an 840MeV electron linear accelerator, aims at generating 9nm FEL radiation with two-stage cascaded HGHG scheme. The project proposal was approved in February 2011 by central government, and the constrction is expected to start in early 2012. This paper describes the preliminary design of this soft X-ray test facility and the R&D progress of the key FEL technologies in the SDUV-FEL test bench.
THPC076	FEL Performance with Focusing Lattice Magnets Alignment Errors	3071
	V.G. Khachatryan, M. Ivanyan CANDLE, Yerevan, Armenia
	At the European XFEL the alignemnet errors of the undulator section quadrupole magnets will be corrected by applying beam based quadrupole alignment methods. Numerical simulations of the SASE process have been conducted to evaluate the FEL power reduction due to residual quadrupole alignment errors. FEL simulations with focusing lattice errors allow choosing an optimal error correction method in terms of FEL performance.
THPC079	Echo-enabled Harmonic Generation at DELTA	3074
	R. Molo, M. Bakr, H. Huck, M. Höner, S. Khan, A. Nowaczyk, A. Schick, P. Ungelenk, M. Zeinalzadeh DELTA, Dortmund, Germany
	Funding: Supported by DFG, BMBF, and the Federal State NRW We present conceptual studies of the realization of the echo-enabled harmonic generation (EEHG) technique proposed by G. Stupakov* as an upgrade of the present coherent harmonic generation (CHG) project at the DELTA storage ring**. EEHG allows to reach shorter wavelengths compared to the CHG scheme. In addition to the optical klystron used for CHG, a third undulator is needed for a second energy modulation of the electron bunch, followed by an additional strong dispersive section. Installing these insertion devices requires a new long straight section in the storage ring and a new lattice configuration. * G. Stupakov Phys. Rev. Lett. 102, 074801 (2009) ** A. Schick et al., this conference
THPC080	Making Engineering Data Available at the European XFEL	3077
	L. Hagge, J. Bürger, J.A. Dammann, S. Eucker, A. Herz, J. Kreutzkamp, S. Panto, S. Sühl, D. Szepielak, N. Welle DESY, Hamburg, Germany
	One of the essential success factors for the European XFEL is up-to-date, complete and consistent engineering data which is readily accessible throughout the project. Such data include for example civil construction drawings of tunnels and buildings; integrated 3D models of accelerator sections; definitions of fabrication processes and test procedures; inspection sheets, test data, standards, contracts and other technical documentation. The data is kept in the DESY Engineering Data Management System (EDMS). The DESY EDMS is the central information platform for the European XFEL and provides procedures for e.g. review & approvals and change management. The poster presents an overview of Engineering Data Management and its benefits at the European XFEL.
THPC081	Status of the Free-Electron Laser FLASH at DESY	3080
	M. Vogt, B. Faatz, J. Feldhaus, K. Honkavaara, S. Schreiber, R. Treusch DESY, Hamburg, Germany
	The free-electron laser facility FLASH at DESY, Germany has been upgraded in 2010. Now, FLASH delivers an electron beam energy up to 1.25 GeV. The longitudinal phase-space is linearized by 3.9 GHz superconducting cavities. The facility delivers to users ultra-short laser like radiation pulses in the range of less than 50 fs to 200 fs in the soft X-ray wavelenth range from 44 down to 4.1 nm. FLASH provides hundreds to thousands pulses per second to users with unprecedented peak brilliance. FLASH will be upgraded with a second undulator beam line and an additional experimental hall. Construction starts Autumn 2011. We summarize the operational status of the ongoing 3rd user period.
THPC082	Properties of the Radiation from the European X-ray Free Electron Laser	3083
	E. Schneidmiller, M.V. Yurkov DESY, Hamburg, Germany
	Recent success of the Linac Coherent Light Source (LCLS) demonstrated feasibility for reliable production, compression, and acceleration of electron beams with emittances significantly smaller than original baseline parameters. The same scenario can be applied to the European XFEL as well. Experimental results from the Photo Injector Test Facility in Zeuthen (PITZ) demonstrated the possibility to generate electron beams with small charge and emittance. Computer modeling of the beam formation system also indicate on the possibility to preserve electron beam quality during acceleration and compression. Recently these trends have been analyzed, and baseline parameters of the European XFEL have been revised. Parameter space has been significantly extended in terms of the bunch charge. As a result, different modes of FEL operation become possible with essentially different properties of the radiation. In this paper we present an overview of radiation properties of SASE FEL radiators driven by electron beam with new baseline parameters.
THPC083	Analysis of Parameter Space of a Kilowatt-scale Free Electron Laser for Extreme Ultraviolet Lithography Driven by L-band Superconducting Linear Accelerator Operating in a Burst Mode	3086
	E. Schneidmiller, V. Vogel, H. Weise, M.V. Yurkov DESY, Hamburg, Germany
	The driving engine of the Free Electron Laser in Hamburg (FLASH) is an L-band superconducting accelerator. It is designed to operate in a burst mode with 800 microsecond pulse duration at a repetition rate of 10 Hz. The maximum accelerated beam current during the macropulse is 10 mA. In this paper we analyze the parameter space for optimum operation of the FEL at the wavelength of 13.5 nm and 6.7 nm. Our analysis shows that the FLASH technology holds great potential for increasing the average power of the linear accelerator and an increase of the conversion efficiency of the electron kinetic energy to the light. Thus, it will be possible to construct a FLASH like free electron laser with an average power up to 3 kW. Such a source meets the requirements of the light source for the next generation lithography.
THPC084	Optical Afterburner for a SASE FEL: First Results from FLASH	3089
	M. Foerst CFEL, Hamburg, Germany M. Gensch HZDR, Dresden, Germany R. Riedel, E. Schneidmiller, N. Stojanovic, F. Tavella, M.V. Yurkov DESY, Hamburg, Germany
	Radiation Pulse from a Self-Amplified Spontaneous Emission Free Electron Laser (SASE FEL) consists out of spikes (wavepackets). Energy loss in the electron beam (averaged over radiation wavelength) also exhibits spiky behaviour on a typical scale of coherence length, and follows the radiation pulse envelope. These modulations of the electron beam energy are converted into large density (current) modulations on the same temporal scale with the help of a dispersion section, installed behind the x-ray undulator. Powerful optical radiation is then generated with the help of a dedicated radiator (afterburner). Envelope of the optical afterburner pulse is closely resembles the envelope of the x-ray pulse. We have recently demonstrated this principle at the Free Electron Laser in Hamburg (FLASH). We use THz undulator that is installed after the main X-ray as both dispersive element and radiator simultaneously. We characterize properties of the optical pulse using standard laser diagnostics techniques (i.e. FROG). Main result comes from the pulse duration measurement that we use to derive envelope of the x-ray radiation pulse duration which is in sub-100 fs range.
THPC085	Effect of mirror-tilt on the mode-structure in an oscillator FEL	3092
	S. Krishnagopal, S.A. Samant BARC, Mumbai, India
	In an oscillator free-electron laser (FEL) the power coupled out depends strongly on the mode configuration at the out-coupling mirror. This mode configuration is affected by many parameters such as the resonator configuration, FEL wavelength, etc. In addition, mirror alignment also plays an important role in determining the mode structure. In this paper we use three-dimensional simulations (GENESIS+OPC), to study the effect of mirror tilt on the out-coupled power. We find that mirror-tilt can severely distort the mode, and can introduce non-Gaussian, non-axisymmetric modes. In this regard the confocal configuration is more robust compared to the concentric.
THPC086	Status Report on FERMI@Elettra Project	3095
	F. Parmigiani, M. Svandrlik, D. Zangrando ELETTRA, Basovizza, Italy
	Funding: This work was supported in part by the Italian Ministry of University and Research under grants FIRB-RBAP045JF2 and FIRB-RBAP06AWK3 FERMI@Elettra, a single-pass FEL user-facility covering the wavelength range from 100 nm (12 eV) to 3 nm (413 eV) located next to the third-generation synchrotron radiation facility Elettra in Trieste, Italy is actually under completion and will start user operation next year. The first seeded lasing was observed in December 2010 and the first experiments have started this year. In this paper an overview of the present status of machine and beamlines systems will be given as well as a status about operation and future upgrade.
THPC087	Saturation Effect on VUV Coherent Harmonic Generation at UVSOR-II	3098
	T. Tanikawa, M. Adachi, M. Katoh, J. Yamazaki, H. Zen UVSOR, Okazaki, Japan M. Hosaka, Y. Taira, N. Yamamoto Nagoya University, Nagoya, Japan
	Light source technologies based on laser seeding are under development at the UVSOR-II electron storage ring. In the past experiments, we have succeeded in generating coherent harmonics (CHs) in deep ultraviolet (UV) and vacuum UV (VUV) region and also in generating CH with variable polarizations in deep UV*. In previous conference, we reported an introduction of new-constructed spectrometer for VUV and results of spectra measurement, undulator gap dependence, and injection laser power dependence on VUV CHs**. This time we have successfully observed saturation on CHs intensities　and have found some interesting phenomena in different harmonic orders. In this conference, we will discuss the results of some systematic measurements and those analytical and particle tracking simulations***. *M. Labat et al., Phys. Rev. Lett. 101 (2008) 164803. **T. Tanikawa et al., Proc. IPAC'10, TUPE029, p. 2206 (2010). ***T. Tanikawa et al., Appl. Phys. Express 3 (2010) 122702.
THPC088	Performance of RF System for XFEL/SPring-8 Injector	3101
	T. Asaka RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan T. Asaka, H. Ego, H. Hanaki, T. Kobayashi, S. Suzuki, T. Taniuchi JASRI/SPring-8, Hyogo-ken, Japan T. Inagaki RIKEN/SPring-8, Hyogo, Japan Y. Otake, T. Shintake, K. Togawa RIKEN Spring-8 Harima, Hyogo, Japan
	In the XFEL/SPring-8 accelerator, the RF processing of an injector for the 8-GeV accelerator were carried out during two months after the installation of all the main components of the accelerator was completed in January 2011. To realize stable bunch compression process without the emittance growth, the injector adopts the combination of an extremely low emittance thermionic gun and multi-stage RF cavities for velocity bunching. In addition, in order to reduce the emittance growth occurring at the transition from the velocity bunching to acceleration, the newly developed L-band APS type accelerating structures and a waveguide system were introduced in the injector. Since an intensity of beam current is affected by the slight variations of RF power and phase of these RF equipment, we have carried out thorough countermeasures to complete highly-stabilized RF systems. Consequently, the stability of RF power and phase in rated operating condition of each RF cavity achieved 20 ppm (std.) and 0.06˚ (std.), respectively. In this paper, we describe the stability performances and RF processing of these RF systems in the injector.
THPC089	Study of a Modified Quasi-periodic Undulator	3104
	A.L. Wu, Q.K. Jia USTC/NSRL, Hefei, Anhui, People's Republic of China
	To suppress high-order harmonic radiation effectively while maintain comparatively higher fundamental radiation intensity, a modified quasi-periodic undulator (QPU) which the magnet blocks have different size is studied in this paper. Then the paper also compares the radiation spectrum of various structural schemes. It is shown that the higher harmonic radiation of this new scheme will be suppressed more effectively than the conventional QPU.
THPC093	Beam Dynamics Simulations for the SwissFEL Injector Test facility	3107
	S. Bettoni, M. Pedrozzi, S. Reiche, T. Schietinger PSI, Villigen, Switzerland
	The SwissFEL under study at PSI will produce 0.1 nm to 0.7 nm wavelength coherent x-ray. The design of the injector is based on the invariant envelope matching scheme, developed for other photoinjectors in the past years. According to this technique the emittance at the exit of the injector can be minimized if some conditions at the entrance of the booster are satisfied. A campaign of simulations has been carried out to verify the impact of the errors of the machine components (RF and magnetic) and laser shaping (transverse and longitudinal) on the final SwissFEL injector emittance. These results have to be used to define the tolerances on the machine and laser.
THPC095	Commissioning Status of the SwissFEL Injector Test Facility	3110
	T. Schietinger, M. Aiba, S. Bettoni, B. Beutner, A. Falone, R. Ganter, R. Ischebeck, F. Le Pimpec, N. Milas, G.L. Orlandi, M. Pedrozzi, E. Prat, S. Reiche, C. Vicario PSI, Villigen, Switzerland
	The SwissFEL injector test facility at the Paul Scherrer Institute has been in operation since August 2010. Its primary goal is the demonstration of a high-brightness electron beam as it will be required to drive the SwissFEL main linac. The injector further serves as a platform for the development and validation of accelerator components needed for the SwissFEL project. We give an overview of recent commissioning activities at about 130 MeV beam energy, with particular emphasis on results from optics matching studies and emittance measurements, the latter obtained with different optics-based methods. A five-cell transverse-deflecting cavity allows studies of the longitudinal bunch charge distribution and slice emittance. Bunch length measurements will become the focus of interest after the installation of a magnetic compression chicane, currently scheduled for the summer of 2011.
THPC096	Soft X-ray Free-electron Laser with a 10-time Reduced Size	3113
	Y.-C. Huang, F.H. Chao, C.H. Chen, K.Y. Huang NTHU, Hsinchu, Taiwan P.J. Chou NSRRC, Hsinchu, Taiwan
	Funding: This work is supported by National Science Council under Contract NSC 99-2112-M-007 -013 -MY3. We present a 30-m long soft x-ray FEL consisting of a 5-MeV photoinjector, a 150 MeV linac, a magnetic chicane compressor, and a 3-m long undulator. We employ both the 3rd and the 4th harmoincs of a Nd laser at 355 and 266 nm, respectively, to illuminate the cathode of the photoinjector. Owing to the beating of the two lasers, the emitted electron beam is modulated at 282 THz. The electrons are further accelerated to 150 MeV and, after acceleration, compressed by 33 times in a magnetic chicane. The temporal compression of the electron macropulse increases the electron bunching frequency to 9.3 PHz, corresponding to a soft x-ray wavelength of 32.2 nm. We adopt a solenoid-derived staggered array undulator* with a 3-m length, 5 mm undulator period, and 1.2 mm gap. With a solenoid field of 10 kG, we estimate an undulator parameter of 0.4 and a corresponding radiation wavelength of 32.2 nm for a 150 MeV driving beam. With 3.3-kA peak current, 0.03% energy spread, 2 mm-mrad emittance, and 80-micron beam radius at the undulator entrance, the GENESIS code predicts 0.2 GW radiation power from the 3-m long undulator for an initial bunching factor of merely 10 ppm. * Y.C. Huang, H.C. Wang, R.H. Pantell, and J. Feinstein, "A staggered-array wiggler for far infrared, free-electron laser operation," IEEE J. Quantum Electronics 30 (1994) 1289.
THPC097	Transverse Alignment Tolerances for the European XFEL Laser Heater	3116
	V.A. Goryashko NASU/IRE, Kharkov, Ukraine M. Dohlus DESY, Hamburg, Germany M. Hamberg, V.G. Ziemann Uppsala University, Uppsala, Sweden
	Funding: Supported by the KTH-SU-UU FEL Center. We study the impact of misalignments between a laser beam and an electron bunch on the energy distribution function of the electron bunch in the laser heater. Transverse position and angular misalignment as well as different spot size of the laser and electron beam are considered. We find that the transverse misalignment makes the energy distribution function narrower compared to the case of ideal adjustment and a distinct peak in the distribution around the initial mean value of the energy appears. We demonstrate that despite these misalignments a uniform heating in terms of the energy spread can be achieved by appropriately adapting the transverse size and power of the laser beam such that the energy distribution function of the electron bunch at the end of the laser heater can be made similar to a Gaussian, thus providing more effective Landau damping against the micro-bunching instability. The laser power mainly determines the local energy spread while the laser spot size governs the shape of the energy distribution function. The transverse oscillations of electrons induced by the magnetic field in the laser heater are found to be non-essential for typical operation parameters.
THPC100	Full Temporal Reconstruction using an Advanced Longitudinal Diagnostic at the SPARC FEL	3119
	G. Marcus, J.B. Rosenzweig UCLA, Los Angeles, California, USA M. Artioli, F. Ciocci, L. Giannessi, A. Petralia, M. Quattromini, V. Surrenti ENEA C.R. Frascati, Frascati (Roma), Italy A. Bacci, M. Bellaveglia, E. Chiadroni, G. Di Pirro, M. Ferrario, G. Gatti, A. Mostacci, A.R. Rossi INFN/LNF, Frascati (Roma), Italy A. Cianchi INFN-Roma II, Roma, Italy V. Petrillo Istituto Nazionale di Fisica Nucleare, Milano, Italy J.V. Rau ISM-CNR, Rome, Italy
	The Production of ultra-short (sub 100 fs) single-spike radiation possessing full longitudinal coherence from a free-electron laser (FEL) has been the subject of intense study. A Frequency-Resolved Optical Gating (FROG) diagnostic has been developed and tested at UCLA, which has the capability of providing a longitudinal reconstruction of these ultra-fast pulses. This paper reports the results of the application of the diagnostic at the SPARC FEL facility.
THPC101	Fitting Formulas for Space-charge Dominated Free-electron Lasers	3122
	G. Marcus, E. Hemsing, J.B. Rosenzweig UCLA, Los Angeles, California, USA
	A simple power-fit formula for calculating the gain length of the fundamental Gaussian mode of a free-electron laser having strong space-charge effects in the 3D regime has been obtained. This tool allows for quick evaluation of the free-electron laser performance in the presence of diffraction, uncorrelated energy spread, and longitudinal space-charge effects. Here, we use it to evaluate the performance of high-gain FEL amplifiers considered candidates as high average power light sources. Results are compared with detailed numerical particle simulations using the free-electron laser code Genesis.
THPC102	Production of Coherent Optical \vCerenkov Radiation in Silica Aerogel	3125
	F.H. O'Shea, J.B. Rosenzweig UCLA, Los Angeles, California, USA
	As a demonstration of the apposite properties of silica aerogel as an electron beam diagnostic we intend to use it to produce coherent optical Cˇ erenkov radation (COCR). In this paper we propose an experiment and provide details of the challenges to be overcome in producing COCR.
THPC103	Beam Dynamics Study of X-band Linac Driven X-ray FELs	3128
	Y. Sun, C. Adolphsen, C. Limborg-Deprey, T.O. Raubenheimer, J. Wu SLAC, Menlo Park, California, USA
	Funding: Work supported by the DOE under Contract DE-AC02-76SF00515 Several linac driven X-ray Free Electron Lasers (XFELs) are being developed to provide high brightness photon beams with very short, tunable wavelengths. In this paper, three XFEL configurations are proposed that achieve LCLS-like performance using X-band linac drivers. These linacs are more versatile, efficient and compact than ones using S-band or C-band rf technology. For each of the designs, the overall accelerator layout and the shaping of the bunch longitudinal phase space are described briefly.
THPC104	Optimization for Single-Spike X-Ray Fels at LCLS with a Low Charge Beam	3131
	L. Wang, Y.T. Ding, Z. Huang SLAC, Menlo Park, California, USA
	The recently commissioned Linac Coherent Light Source is an x-ray free-electron laser at the SLAC National Accelerator Laboratory, which is now operating at x-ray wavelengths of 20-1.2 Angstrom with peak brightness nearly ten orders of magnitude beyond conventional synchrotron sources. At the low charge operation mode (20 pC), the x-ray pulse length can be <10 fs. In this paper we report our numerical optimization and simulations to produce even shorter x-ray pulses by optimizing the machine and undulator setup. In the soft x-ray regime, with the help of slotted-foil or undulator taper, a single spike x-ray pulse is achievable with peak FEL power of 30 GW.
THPC105	An Electron Bunch Compression Scheme for a Superconducting Radio Frequency Linear Accelerator Driven Light Source	3134
	C. Tennant, S.V. Benson, D. Douglas, P. Evtushenko, R.A. Legg JLAB, Newport News, Virginia, USA
	Funding: Support by US DoE contract #DE-AC05-060R23177. We describe an electron bunch compression scheme suitable for use in a light source driven by a superconducting radio frequency (SRF) linac. The key feature is the use of a recirculating linac to perform the initial bunch compression. Phasing of the second pass beam through the linac is chosen to de-chirp the electron bunch prior to acceleration to the final energy in an SRF linac ("afterburner"). The final bunch compression is then done at maximum energy. This scheme has the potential to circumvent some of the most technically challenging aspects of current longitudinal matches; namely transporting a fully compressed, high peak current electron bunch through an extended SRF environment, the need for a RF harmonic linearizer and the need for a laser heater. Additional benefits include a substantial savings in capital and operational costs by efficiently using the available SRF gradient.
THPC106	Commissioning Status of the Fritz Haber Institute THz FEL	3137
	A.M.M. Todd, H. Bluem, V. Christina, M.D. Cole, J. Ditta, D. Dowell, K. Jordan, R. Lange, J.H. Park, J. Rathke, T. Schultheiss, L.M. Young AES, Princeton, New Jersey, USA W. Erlebach, S. Gewinner, H. Junkes, A. Liedke, G. Meijer, W. Schöllkopf, G. von Helden FHI, Berlin, Germany S.C. Gottschalk STI, Washington, USA
	The THz Free-Electron Laser (FEL) at the Fritz Haber Institute (FHI) of the Max Planck Society in Berlin is designed to deliver radiation from 3 to 300 microns using a single-plane-focusing mid-IR undulator and a two-plane-focusing far-IR undulator that acts as a waveguide for the optical mode. A key aspect of the accelerator performance is the low longitudinal emittance, < 50 keV-psec, that is specified to be delivered at 200 pC bunch charge and 50 MeV from a gridded thermionic electron source. We utilize twin accelerating structures separated by a chicane to deliver the required performance over the < 20 - 50 MeV energy range. The first structure operates at near fixed field while the second structure controls the output energy, which, under some conditions, requires running in a decelerating mode. "First Light" is targeted for the centennial of the sponsor in October 2011 and we will describe progress in the commissioning of this device to achieve this goal. Specifically, the measured performance of the accelerated electron beam will be compared to design simulations and the observed matching of the beam to the mid-IR wiggler will be described.
THPC133	Pre-Conceptual Design Requirements For The MaRIE Facility At LANL And The Resulting X-Ray Free Electron Laser Baseline Design	3197
	R.L. Sheffield, B.E. Carlsten LANL, Los Alamos, New Mexico, USA
	The MaRIE (Matter-Radiation Interactions in Extremes) facility is being proposed to advance materials science by the concurrent utilization of a diverse set of highly penetrating probes. These probes will provide the basis for developing materials that will perform predictably and on demand with currently unattainable lifetimes in extreme environments. The MaRIE facilities, the Multi-Probe Diagnostic Hall (MPDH), the Fission and Fusion Materials Facility (F3), and the Making, Measuring, and Modeling Materials (M4) Facility will each have experimental needs for one or more high-energy x-ray beam probes, but all require a 50-keV coherent source of greater than 1010 photons in less than 1 ps. Because of space considerations at the facility, a high-gradient design is being investigated that will use a X-band RF systems to drive a 20-GeV normal-conducting linac. Experimental requirements drive a need for multiple photon bunches over time durations greater than 1 microsecond, as well as interleaving 0.1 nC very-low-emittance bunches with 2-nC electron bunches. This paper will cover an overview of the scientific requirements for the MaRIE XFEL and the baseline XFEL design.