IPAC2012 - List of Keywords (FEL)

Paper	Title	Other Keywords	Page
MOOAA02	Instrumentation and Diagnostics for High Repetition Rate Linac-driven FELs	linac, emittance, diagnostics, laser	23
	J.M. Byrd, S. De Santis, L.R. Doolittle, D. Filippetto, G. Huang, M. Placidi, A. Ratti LBNL, Berkeley, California, USA
	Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. One of the concepts for the next generation of linac-driven FELs is a cw superconducting linac driving an electron beam with MHz repetition rates. The beam is then switched into an array of independently configurable FELs. The demand for high brightness beams and the high rep-rate presents a number of challenges for the instrumentation and diagnostics. The high rep-rate also presents opportunities for increased beam stability because of the ability for much higher sampling rates for beam-based feedbacks. In this paper, we present our plans for instrumentation and diagnostics for such a machine.
	Slides MOOAA02 [1.710 MB]

MOOBC03	A Multi Purpose X Band Accelerating Structure	wakefield, linac, resonance, alignment	70
	M.M. Dehler, A. Citterio, R. Zennaro Paul Scherrer Institut, Villigen, Switzerland G. D'Auria, C. Serpico ELETTRA, Basovizza, Italy D. Gudkov, A. Samoshkin JINR, Dubna, Moscow Region, Russia S. Lebet, G. Riddone, J. Shi CERN, Geneva, Switzerland
	In a collaboration between CERN, PSI and Sincrotrone Trieste (ST), a series of four multipurpose X-band accelerating structures has been designed and fabricated. The structures have 72 cells with a phase advance of 5 pi/6 and include upstream and downstream wakefield monitors to measure the beam alignment. We give an overview of the electrical and mechanical design and describe the fabrication of the first units. We also present the results of the low level RF tests. Using measurements of the internal cell to cell misalignment, the residual transverse wake and the noise floor of the wake field monitors are computed. Furthermore, we present the first experiences running the structures under high power.
	Slides MOOBC03 [15.521 MB]

MOEPPB014	Time Jitter Measurements in Presence of a Magnetic Chicane in the FERMI@elettra Linac	electron, linac, laser, dipole	109
	G. Penco, P. Craievich, S. Di Mitri, M.M. Milloch, F. Rossi ELETTRA, Basovizza, Italy
	Accurate and highly stable temporal synchronization between an electron bunch and a pulse from an external seed laser is one of the key requirements for successful operation of a seeded FEL in the XUV and soft x-ray regime. These requirements become more stringent when the electron bunch is longitudinally compressed to sub-ps durations in order to increase the current for more efficient FEL action. In this paper we present experimental measurements of the electron bunch arrival time jitter after the first magnetic compressor of FERMI@Elettra seeded FEL as a function of the compression factor. The experimental behavior of the pulse-to-pulse time jitter agrees both with results from tracking code simulations and with predictions from an analytical approach that takes into account the different sources of time jitter in FERMI, namely the photoinjector drive laser, the RF accelerating cavity phases and voltages, and fluctuations in the chicane bending magnet currents. We also present predictions for the expected arrival time jitter in the final configuration of FERMI that includes two bunch compressors and for which the synchronization requirement is of order 100 fs or better.

MOPPC090	Coupling Modulator Simulations into an FEL Amplifier for Coherent Electron Cooling	electron, simulation, radiation, positron	346
	I.V. Pogorelov, G.I. Bell, D.L. Bruhwiler, B.T. Schwartz, S.D. Webb Tech-X, Boulder, Colorado, USA Y. Hao, V. Litvinenko, G. Wang BNL, Upton, Long Island, New York, USA
	Funding: Work supported by the US DOE Office of Science, Office of Nuclear Physics under grant numbers DE-FG02-08ER85182 and DE-SC0000835. Next-generation ion colliders will require effective cooling of high-energy hadron beams. Coherent electron cooling (CeC) can in principle cool relativistic hadron beams on orders-of-magnitude shorter time scales than other techniques. Particle-in-cell (PIC) simulations of a CeC modulator with the parallel VORPAL framework generate macro-particle distributions with subtle but important phase space correlations. To couple these macro-particles into a 3D simulation code for the free-electron laser (FEL) amplifier, while retaining all details of the 6D phase space coordinates, we implemented an alternative approach based on particle-clone pairs. Our approach allows for self-consistent treatment of shot noise and spontaneous radiation, with no need for quiet-start initialization of the FEL macro-particles' ponderomotive phase. We present results of comparing fully 3D amplifier modeling based on the particle-clone approach vs GENESIS simulations where distribution of bunching parameter was used as input. We also discuss enabling direct coupling of the VORPAL delta-f simulation output into 3D distributions of particle-clone pairs. V.N. Litvinenko and Y.S. Derbenev, Phys. Rev. Lett. 102, 114801 (2009). ** V.N. Litvinenko, "Macro-particle FEL model with self-consistent spontaneous radiation," unpublished (2002).

MOPPD016	Status of Proof-of-principle Experiment for Coherent Electron Cooling	electron, gun, ion, wiggler	400
	I. Pinayev, S.A. Belomestnykh, I. Ben-Zvi, J. Bengtsson, A. Elizarov, A.V. Fedotov, D.M. Gassner, Y. Hao, D. Kayran, V. Litvinenko, G.J. Mahler, W. Meng, T. Roser, B. Sheehy, R. Than, J.E. Tuozzolo, G. Wang, S.D. Webb, V. Yakimenko BNL, Upton, Long Island, New York, USA G.I. Bell, D.L. Bruhwiler, V.H. Ranjbar, B.T. Schwartz Tech-X, Boulder, Colorado, USA A. Hutton, G.A. Krafft, M. Poelker, R.A. Rimmer JLAB, Newport News, Virginia, USA M.A. Kholopov, P. Vobly BINP SB RAS, Novosibirsk, Russia
	Funding: US DOE Office of Science, DE-FC02-07ER41499, DE-FG02-08ER85182; NERSC DOE contract No. DE-AC02-05CH11231. Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron colliders. To verify the concept we conduct proof-of-the-principle experiment at RHIC. In this paper, we describe the current experimental setup to be installed into 2 o’clock RHIC interaction regions. We present current design, status of equipment acquisition and estimates for the expected beam parameters.

MOPPD038	Simulation Study of Electron Response Amplification in Coherent Electron Cooling	electron, ion, bunching, undulator	448
	Y. Hao, V. Litvinenko BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. In Coherent Electron Cooling (CEC), it is essential to study the amplification of electron response to a single ion in the FEL process, in order to proper align the electron beam and the ion beam in the kicker to maximize the cooling effect. In this paper, we use Genesis to simulate the amplified electron beam response of single ion in FEL amplification process, which acts as 'Green function' of the FEL amplifier.

MOPPP012	Experimental Observation of Energy Modulation in Electron Beams Passing through Terahertz Dielectric Wakefield Structures	wakefield, bunching, radiation, acceleration	595
	S.P. Antipov, C.-J. Jing, A. Kanareykin, P. Schoessow Euclid TechLabs, LLC, Solon, Ohio, USA M.G. Fedurin, K. Kusche, V. Yakimenko BNL, Upton, Long Island, New York, USA W. Gai, A. Zholents ANL, Argonne, USA B.C. Jiang SINAP, Shanghai, People's Republic of China
	Funding: DOE SBIR. We report observation of a strong wakefield induced energy modulation in an energy-chirped electron bunch passing through a terahertz dielectric-lined waveguide. This modulation can be effectively converted into a spatial modulation by means of a chicane, forming micro-bunches (density modulation) with a periodicity of 0.5 - 1 picosecond, hence capable of driving coherent THz radiation. The experimental results agree well with theoretical predictions.

MOPPP013	Passive Momentum Spread Compensation by a “Wakefield Silencer”	wakefield, electron, dipole, simulation	598
	S.P. Antipov, C.-J. Jing, A. Kanareykin, P. Schoessow Euclid TechLabs, LLC, Solon, Ohio, USA M.G. Fedurin, K. Kusche, V. Yakimenko BNL, Upton, Long Island, New York, USA W. Gai, A. Zholents ANL, Argonne, USA
	Funding: DOE SBIR. We report an observation of de-chirping of a linearly chirped (in energy) electron bunch by its passage through a 5 cm long dielectric loaded waveguide structure. The experiment was conducted at the ATF facility at BNL according to a concept dubbed a wakefield silencer originally developed at the ANL AATF, which involves defining the electron bunch peak current distribution and selecting the optimal waveguide structure suitable for chirp cancellation using self-induced wakefields of the electron bunch. Our experiment has been carried out with a 247 micron triangular beam with a 200 keV energy spread, which was reduced by a factor of three to approximately 70 keV by passing it through a 0.95 THz dielectric-lined structure. Theoretical analysis supports the experimental results. Further exploration and applications of this technique will be discussed as well. M. Rosing, J. Simpson, Argonne Wakefield Accelerator Note, WF -144 (1990).

MOPPP021	Longitudinal Beam Dynamics at the ALICE Acclerator R&D Facility	booster, linac, simulation, gun	610
	F. Jackson, D. Angal-Kalinin, S.P. Jamison, J.W. McKenzie, T.T. Ng, Y.M. Saveliev, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The ALICE facility is an energy recovery test accelerator whose applications include an IR-FEL and THz generation. Of primary importance to the performance of the main ALICE applications is the understanding and control of the longitudinal dynamics, which are less amenable to measurement than the transverse. The longitudinal dynamics of the beam evolve are studied in simulation and experiment in several areas of the machine. Simulations of the low energy injector where space charge and velocity bunching may occur are presented. Path length measurement using time-of-arrival monitors are carried out.

MOPPP022	ALICE: Status, Developments and Scientific Programme	gun, radiation, acceleration, cryomodule	613
	Y.M. Saveliev STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	ALICE (Accelerators and Lasers In Combined Experiments) is a multifunctional ERL based R&D facility that operates in various regimes, both energy recovery and non energy recovery, depending on the project undertaken (beam energy 10-28MeV, bunch charge 20-100pC, train length from a single bunch to 100us). In early 2012, the DC HV photoinjector gun is expected to begin operation at nominal 350kV and a new cryomodule, a result of a wide international collaboration, will be installed and commissioned on ALICE. The improvements in beam dynamics and the overall beam quality will be discussed in this paper. The overview of the ALICE scientific programme including IR-FEL lasing and its application for scanning near field optical microscopy, generation and applications of coherent broadband THz radiation for life sciences and solid state physics, studies of the first non-scaling FFAG EMMA for which ALICE serves as an injector and accelerator physics research will also be presented.

MOPPP028	SRF Photoinjector for Proof-of-principle Experiment of Coherent Electron Cooling at RHIC	electron, SRF, gun, emittance	622
	D. Kayran, S.A. Belomestnykh, I. Ben-Zvi, J.C. Brutus, X. Liang, G.T. McIntyre, I. Pinayev, B. Sheehy, J. Skaritka, T. Srinivasan-Rao, R. Than, J.E. Tuozzolo, Q. Wu, T. Xin BNL, Upton, Long Island, New York, USA V. Litvinenko, M. Ruiz-Osés Stony Brook University, Stony Brook, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy and by Stony Brook DOE grant DE-SC0005713. Coherent Electron Cooling (CEC) based on FEL amplifier promises to be a very good way to cool protons and ions at high energies. A proof of principle experiment to demonstrate cooling at 40 GeV/u is under construction at BNL. One of possible sources to provide sufficient quality electron beam for this experiment is a SRF photoinjector. In this paper we discuss design and simulated performance of the photoinjector based on existing 112 MHz SRF gun and newly designed single-cavity SRF linac operating at 704 MHz.

MOPPP032	Longitudinal Phase Space Studies at the PITZ Facility	electron, laser, radiation, gun	631
	M. Mahgoub, J.W. Bähr, H.-J. Grabosch, M. Groß, L. Hakobyan, G. Klemz, G. Kourkafas, M. Krasilnikov, D. Malyutin, A. Oppelt, M. Otevřel, B. Petrosyan, K. Rosbach, F. Stephan, G. Vashchenko DESY Zeuthen, Zeuthen, Germany I.I. Isaev MEPhI, Moscow, Russia Ye. Ivanisenko IERT, Kharkov, Ukraine M. Khojoyan ANSL, Yerevan, Armenia J. Li USTC/NSRL, Hefei, Anhui, People's Republic of China B. Marchetti INFN-Roma II, Roma, Italy D. Richter HZB, Berlin, Germany J. Rönsch-Schulenburg Uni HH, Hamburg, Germany
	Photoinjectors are a cornerstone for short-wavelength Free Electron Lasers (FELs) like FLASH and the European XFEL in Hamburg, Germany. The Photo Injector Test facility at DESY, location Zeuthen (PITZ), was built to develop and optimize such photoinjectors. The PITZ facility is capable of generating long trains of electron bunches, which can be accelerated up to ~25 MeV/c. Studying and optimizing the longitudinal properties of the electron bunch is an important topic at PITZ. A streak system consisting of Silica Aerogel radiators, optical transition radiation (OTR) screens, optical transmission line, and a streak camera is used to study the longitudinal properties with an accuracy of some ps. Due to the high radiation level in the facility, many of the lenses in the optical transmission line have turned brown, reducing the efficiency of the system. Some of the lenses were recovered by baking them up to 180°C. In contrast, few sensitive objective lenses can not be baked, rather they were recovered via exposure to infrared radiation with the proper wave length. An overview of the system, the difficulties, and the modifications needed to overcome the radiation effects are presented.

MOPPP033	Diagnostics at PITZ 2.0 Beamline: Status and New Developments	emittance, electron, diagnostics, dipole	634
	M. Otevřel, A. Donat, H.-J. Grabosch, M. Groß, L. Hakobyan, H.M. Henschel, L. Jachmann, M. Khojoyan, G. Klemz, W. Köhler, G. Koss, G. Kourkafas, M. Krasilnikov, K. Kusoljariyakul, H. Leich, J. Li, M. Mahgoub, D. Malyutin, B. Marchetti, J. Meissner, A. Oppelt, M. Penno, B. Petrosyan, M. Pohl, S. Riemann, M. Sachwitz, B. Schöneich, J. Schultze, A. Shapovalov, F. Stephan, F. Tonisch, G. Vashchenko, L.V. Vu, T. Walter, S. Weisse, R.W. Wenndorff, M. Winde DESY Zeuthen, Zeuthen, Germany G. Asova INRNE, Sofia, Bulgaria N.I. Brusova, L.V. Kravchuk, V.V. Paramonov RAS/INR, Moscow, Russia A. Gonnin, M. Joré, B. Mercier, C. Prevost, A. Variola LAL, Orsay, France I.I. Isaev MEPhI, Moscow, Russia Ye. Ivanisenko IERT, Kharkov, Ukraine D. Richter HZB, Berlin, Germany S. Rimjaem Chiang Mai University, Chiang Mai, Thailand A.A. Zavadtsev, D.A. Zavadtsev Nano, Moscow, Russia
	The main aim of the Photo Injector Test Facility at DESY, Zeuthen (PITZ) site is to develop and test an FEL photo injector system capable of producing high charge short electron bunches of lowest possible transverse emittance to allow optimum FEL performance. The last major beamline upgrade realized in the second half of the year 2011 completed the evolution of the PITZ setup ongoing since 2005. The most recent upgrades include the installation of a new RF deflecting cavity - a prerequisite for longitudinal emittance and high resolution slice emittance measurements and installation of a new dispersive section for longitudinal phase space diagnostics of the high energy electron bunches. The paper will give an overview on electron beam diagnostics at PITZ, including the above mentioned upgrades.

MOPPP040	Resistive Wall Heating of the Undulator in High Repetition Rate FELs	undulator, electron, wakefield, impedance	652
	J. Qiang, J.N. Corlett, P. Emma LBNL, Berkeley, California, USA J. Wu SLAC, Menlo Park, California, USA
	Funding: Work supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. In next generation high repetition rate FELs, beam energy loss due to resistive wall wakefields will produce significant amount of heat. The heat load for a superconducting undulator (operating at low temperature), must be removed and will be expensive to remove. In this paper, we study this effect in an undulator proposed for a Next Generation Light Source (NGLS) at LBNL. We benchmark our calculations with measurements at the LCLS and carry out detailed parameter studies using beam from a start-to-end simulation. Our preliminary results suggest that the heat load in the undulator is about 2 W/m with an aperture size of 6 mm for nominal NGLS design parameters.

MOPPP071	In Vacuum Conduction Cooled Superconducting Switch for Insertion Devices with Variable Period Length	vacuum, power-supply, insertion, insertion-device	726
	T. Holubek, T. Baumbach, S. Casalbuoni, S. Gerstl, A.W. Grau, M. Hagelstein, D. Saez de Jauregui Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany C. Boffo, W. Walter BNG, Würzburg, Germany
	Switching the period length allows to increase the tunability of an insertion device. This can be realized in superconducting insertion devices (IDs) by reversing the current in a separately powered subsets of the superconducting windings. In order to use only one power supply instead of two for the two circuits, reducing the thermal input to the device, work is ongoing at ANKA to develop a superconducting switch. In this work we present the results of the test of an in-vacuum housed, conduction-cooled superconducting switch.

MOPPP076	Design Considerations for a Hybrid Undulator Applied in a Terahertz FEL Oscillator	undulator, electron, radiation, cavity	738
	B. Qin, M. Fan, Y.Q. Xiong Huazhong University of Science and Technology (HUST), Wuhan, People's Republic of China Y.J. Pei USTC/NSRL, Hefei, Anhui, People's Republic of China P. Tan HUST, Wuhan, People's Republic of China
	A planer undulator using hybrid permanent magnet scheme was designed for a FEL based 1THz~3THz radiation source. The influence of the undulator magnetic field errors, including peak field shift and field integrals errors, on the coherent radiation performance such as the gain per pass is investigated. And finally specifications of the undulator are determined.

MOPPP085	Single Electron Dynamic of Microwave Undulator	electron, undulator, radiation, free-electron-laser	753
	C. Chang, J. Neilson, C. Pellegrini, M. Shumail, S.G. Tantawi SLAC, Menlo Park, California, USA
	The analytical and numerical calculations for the dynamic of single electron and beam in RF undulator have been conducted and compared. The transverse and longitudinal velocity, trajectory, energy variation, and the spontaneous radiation are studied. It is found that the forward and backward wave (FW/BW) components have different contribution on electron motion and radiation, most of the energy spread comes from FW component, in other words, the effect of FW on modulating the electron energy is much stronger than that of BW for the same undulating-amplitude value, which mechanism has been analyzed.

MOPPR017	Preliminary Measurement Results of the Upgraded Energy BPM at FLASH	pick-up, LLRF, electron, controls	813
	U. Mavrič, M. Felber, C. Gerth, H. Schlarb DESY, Hamburg, Germany W. Jałmużna, A. Piotrowski TUL-DMCS, Łódź, Poland
	The energy beam position monitor in the dispersive section of the two bunch compressors is a valuable instrument for regular operation of FLASH. Recently, an upgrade of the existing instrument to a uTCA form factor has been started. The basic principle of the time-of-flight measurement will remain the same, however the detection of the phases and amplitudes of two pulses has been moved to the programmable gate array. Other changes include different RF frequencies of detection, optimization of the front-end section and integration into the control system. A preliminary version of the system has been tested at FLASH and the results are presented in the paper.

MOPPR019	Beam Profile Imaging Based on Backward Transition Radiation in the Extreme Ultraviolet Region	radiation, electron, target, diagnostics	819
	L.G. Sukhikh, S. Bajt, G. Kube DESY, Hamburg, Germany W. Lauth IKP, Mainz, Germany Yu.A. Popov, A. Potylitsyn Tomsk Polytechnic University, Tomsk, Russia
	Backward transition radiation (BTR) in the optical spectral region is widely used for beam profile diagnostics in modern electron linacs. However, the experience from linac based light sources shows that BTR diagnostics might fail because of coherence effects in the emission process. To overcome this problem of coherent emission it was proposed to use BTR in the extreme ultraviolet (EUV) region, and measurements of the angular EUV BTR distribution were presented in Ref. . This contribution summarizes the results of a beam profile imaging experiment using EUV BTR. The experiment was carried out using the 855 MeV electron beam of the Mainz Microtron MAMI. EUV BTR was generated at a molybdenum target deposited onto a silicon substrate, and imaging was realized using a spherical multilayer mirror which was optimized for a wavelength of 19 nm. Preliminary results will be presented and compared to ordinary optical BTR imaging together with a discussion of future possibilities of the proposed diagnostic method. L.G. Sukhikh et al., Nucl. Instrum. Methods A623, 567 (2010). ** L.G. Sukhikh et al., Proc. of DIPAC-2011, Hamburg (Germany), 544 (2011).

MOPPR032	Electron Beam Diagnostics based on Transverse Feedback System at Duke Storage Ring	storage-ring, feedback, electron, monitoring	849
	W. Xu, D.H. He USTC/NSRL, Hefei, Anhui, People's Republic of China J.Y. Li, W. Wu, Y.K. Wu FEL/Duke University, Durham, North Carolina, USA
	Funding: This work is supported in part by the US DOE grant no. DE-FG02-97ER41033. To combat electron beam instabilities, a field programmable gate array (FPGA) based bunch-by-bunch transverse feedback (TFB) has been developed for the Duke storage ring. While it is capable of suppressing transverse beam instabilities for multi-bunch operation, the TFB system has not been needed for typical operation of the Duke storage ring FEL. To explore the great potential of this system, we have focused on the development of TFB based beam diagnostics. A TFB based tune measurement system has been developed using two methods: the tune scan method and tune monitoring method. With the tune monitoring method, a much faster method of the two, we have studied the tune stability of the electron beam in the Duke storage ring. This tune measurement system also allows us to conduct chromaticity measurements more quickly, compared with the existing chromaticity measurement system using a network analyzer. Finally, the TFB based tune system has been used to calibrate the tune knob and chromaticity knob for the Duke storage ring.

MOPPR035	Study of the Signal Processing System for a Cavity Beam Position MonitorS	cavity, electron, factory, simulation	855
	B.P. Wang, Y.B. Leng, L.Y. Yu, W.M. Zhou SINAP, Shanghai, People's Republic of China Z.C. Chen, R.X. Yuan, N. Zhang SSRF, Shanghai, People's Republic of China
	A cavity beam position monitor (CBPM), which can realize nanometer-level resolution as reported, is important and indispensable for a free electron laser (FEL) facility. A prototype of CBPM, with resonant frequency of 5712 MHz, has been installed in the Shanghai deep ultraviolet free-electron laser source (SDUV-FEL) facility. A plug & play CBPM signal processor based on a broadband oscilloscope embedded IOC and FFT technology has been developed to do quick evaluation of prototype. According to the evaluation results, a series of simulation using Monte Carlo simulation method, has been carried as a guideline for the design of dedicated CBPM signal processing system. The development progress of signal processing system will be introduced as well.

TUXB02	Review of ERL Projects at KEK and Around the World	linac, gun, electron, emittance	1040
	N. Nakamura KEK, Ibaraki, Japan
	Future synchrotron light sources based on energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. The Japanese collaboration team is making efforts for realizing an ERL-based VUV and X-ray source with R&D efforts on super-conducting cavities and the electron gun at KEK and elsewhere. This presentation will describe the developments of the compact ERL project and the outline of the 3-GeV ERL light source project at KEK and also review ERL projects around the world, including potential applications to colliders.
	Slides TUXB02 [25.328 MB]

TUOBB03	Status of the FERMI@Elettra Project	laser, electron, radiation, photon	1092
	M. Svandrlik, E. Allaria, L. Badano, S. Bassanese, F. Bencivenga, E. Busetto, C. Callegari, F. Capotondi, D. Castronovo, M. Coreno, P. Craievich, I. Cudin, G. D'Auria, M. Dal Forno, M.B. Danailov, R. De Monte, G. De Ninno, A.A. Demidovich, M. Di Fraia, S. Di Mitri, B. Diviacco, A. Fabris, R. Fabris, W.M. Fawley, M. Ferianis, E. Ferrari, L. Fröhlich, P. Furlan Radivo, G. Gaio, L. Giannessi, R. Gobessi, C. Grazioli, E. Karantzoulis, M. Kiskinova, M. Lonza, B. Mahieu, C. Masciovecchio, S. Noè, F. Parmigiani, G. Penco, E. Principi, F. Rossi, L. Rumiz, C. Scafuri, S. Spampinati, C. Spezzani, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, M. Zaccaria, D. Zangrando, M. Zangrando ELETTRA, Basovizza, Italy
	Funding: The work was supported in part by the Italian Ministry of University and Research under grants FIRB-RBAP045JF2 and FIRB-RBAP06AWK3. The FERMI@Elettra seeded Free Electron Laser has provided the first photons to the experimental stations during 2011. The first FEL line in operation is FEL-1, covering the wavelength range between 100 nm and 20 nm. The facility will be opened to users by the end of 2012. In the meantime the installation of the second FEL line, FEL-2 covering the higher energy range down to 4 nm, is progressing on schedule and first tests have started. A description of the status of the project is presented here.
	Slides TUOBB03 [5.316 MB]

TUEPPB010	Oscillator Seeding of a High Gain Harmonic Generation FEL in a Radiator-first Configuration	electron, radiation, laser, bunching	1137
	P.R. Gandhi, J.S. Wurtele UCB, Berkeley, California, USA G. Penn, M.W. Reinsch LBNL, Berkeley, California, USA
	A longitudinally coherent X-ray pulse from a high repetition rate free electron laser (FEL) is desired for a wide variety of experimental applications. However, generating such a pulse with a repetition rate greater than ~1 MHz is a significant challenge. The desired high rep rate sources, primarily high harmonic generation with intense lasers in gases or plasmas, do not exist now, and, for the multi-MHz bunch trains that superconducting accelerators can potentially produce, are likely not feasible with current technology. In this paper, we propose to place an oscillator downstream of a radiator. The oscillator generates radiation that is used as a seed for a high gain harmonic generation (HGHG) FEL which is upstream of the oscillator. For the first few pulses the oscillator builds up power and, until power is built up, the radiator has no HGHG seed. As power in the oscillator saturates, the HGHG is seeded and power is produced. The dynamics and stability of this radiator-first scheme is explored analytically and numerically. A single-pass map is derived using a semi-analytic model for FEL gain and saturation. Iteration of the map is shown to be in good agreement with simulations.

TUEPPB011	Echo Enabled High Mode Generation for X-ray FELs	laser, electron, bunching, free-electron-laser	1140
	E. Hemsing SLAC, Menlo Park, California, USA A. Marinelli UCLA, Los Angeles, California, USA
	Funding: Work supported by U.S. DOE under Contract Nos. DE-AC02-76SF00515 and DE-FG02-07ER46272. We describe a simple technique based on a modified echo-enabled harmonic generation (EEHG) scheme to manipulate the three-dimensional electron beam microbunching distribution in order to generate higher-order optical modes in an FEL. As with EEHG, the concept uses two modulators and two chicanes to produce microbunching. However, in one of the modulators, the resonant interaction with the laser has a well-defined transverse structure that becomes strongly correlated to the longitudinal microbunching distribution. Both high-harmonic frequencies and high transverse mode numbers can be generated through a transversely-dependent echo effect.

TUPPC047	New Storage Ring Lattice for the Duke FEL Wiggler Switchyard System	wiggler, lattice, storage-ring, quadrupole	1272
	H. Hao, J.Y. Li, Y.K. Wu FEL/Duke University, Durham, North Carolina, USA
	Funding: This work is supported in part by the US DOE grant no. DE-FG02-97ER41033. The Duke storage ring is a dedicated drive for the OK-4 FEL and OK-5 FEL, and for the state-of-the-art Compton gamma-ray source, High Intensity Gamma-Ray Source (HIGS). To produce FEL lasing below 190 nm and gamma-ray beams above 100 MeV, the FEL system needs to be upgraded by adding two helical OK-5 wigglers to increase the FEL gain with four OK5 wigglers for the VUV operation. To simultaneously preserve the linear polarization capability of the gamma-ray beam produced by the planar OK-4 FEL, a wiggler switchyard system is under development which will enable the switch between two planar OK-4 wigglers and two helical OK-5 wigglers in the middle of the FEL straight. In this work, we present the new magnetic lattice designed for the operation of the wiggler switchyard system. This new lattice is developed with great flexibility for the operation with different numbers of FEL wigglers, variable betatron tunes, and adjustable electron beam sizes at the collision point for the HIGS. In addition, the new lattice is developed for the operation in a wide range of energies, from 280 MeV to 1.2 GeV, with proper nonlinear dynamics compensations in order to realize a large dynamic aperture.

TUPPP005	LUNEX5: A French FEL Test Facility Light Source Proposal	laser, emittance, electron, undulator	1611
	A. Loulergue, C. Benabderrahmane, M. Bessière, P. Betinelli-Deck, F. Bouvet, A. Buteau, L. Cassinari, M.-E. Couprie, J. Daillant, J.-C. Denard, P. Eymard, B. Gagey, C. Herbeaux, M. Labat, A. Lestrade, P. Marchand, J.L. Marlats, C. Miron, P. Morin, A. Nadji, F. Polack, J.B. Pruvost, F. Ribeiro, J.P. Ricaud, P. Roy SOLEIL, Gif-sur-Yvette, France S. Bielawski, C. Evain, C. Szwaj PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France B. Carré CEA/DSM/DRECAM/SPAM, Gif-sur-Yvette, France G. Devanz, M. Luong CEA/DSM/IRFU, France L. Farvacque, G. Lebec ESRF, Grenoble, France G. Lambert, A. Lifschitz, V. Malka, A. Rousse LOA, Palaiseau, France M. Le Parquier CERLA, Villeneuve d'Ascq, France J. Lüning CCPMR, Paris, France R. Roux LAL, Orsay, France
	LUNEX5 is a new synchrotron FEL source project aiming at delivering short and coherent X-ray pulses to probe ultrafast phenomena at the femto-second scale, to investigate extremely low density samples as well as to image individual nm scale objects. The proposed machine layout is based on a 400 MeV super-conducting Conventional Linear Accelerator (CLA) mainly composed of 2 XFEL type cryo-modules together with a normal-conducting high brightness photo RF gun. This present mature and reliable technology is able to deliver high quality electron bunches up to few kHz suitable for user experiments. Further more, the last decade improvement in synchronization and stability offer a fertile land to explore the different and innovative seeded FEL operations aiming at producing higher coherence and energetic X-rays for the pilot user full benefits. In parallel of the CLA branch, the very promising and highly innovative Laser Wake-Field Accelerator (LWFA) able to produce very short electron bunches in the range of the femto-second and high peak current up to few GeV is foreseen as a FEL bench test using the same undulator lines.

TUPPP045	Creation of FELWI using Large Amplification Regime	electron, undulator, resonance, microtron	1707
	K.B. Oganesyan ANSL, Yerevan, Armenia A.I. Artemyev, D.N. Klochkov GPI, Moscow, Russia Y. Rostovtsev University of North Texas, Denton, Texas, USA
	Funding: ISTC project A-1602 The interaction between noncollinear laser and relativistic electron beams in static magnetic undulator has been studied within the framework of dispersion equations. In the limit of small-signal gain the spatial growth rates are found for the collective (Raman) and single-electron (Thompson) regimes. For a free-electron laser without inversion (FELWI), estimates of the threshold laser power are found. The large-amplification regime should be used to bring an FELWI above the threshold laser power.

TUPPP048	Increasing the Spectral Range of the CLIO Infrared FEL User Facility by Reducing Diffraction Losses	undulator, vacuum, laser, simulation	1709
	J.-M. Ortega, G. Perilhous, R. Prazeres LCP/CLIO, Orsay, Cedex, France H.B. Abualrob, P. Berteaud, L. Chapuis, M.-E. Couprie, T.K. El Ajjouri, F. Marteau, J. Vétéran SOLEIL, Gif-sur-Yvette, France J.P. Berthet, F. Glotin CLIO/ELISE/LCP, Orsay, France
	Funding: CNRS/RTRA The infrared free-electron laser offers a large tunability since the FEL gain remains high throughout the infrared spectral range, and the reflectivity of metal mirrors remains also close to 1. The main limitation comes from the diffraction of the optical beam due to the finite size of the vacuum chamber of the undulator. At CLIO, we have obtained previously* an FEL tunable from 3 to 150 μm by operating the accelerator between 50 and 14 MeV. However, we found that a phenomenon of “power gaps“ is observed in far-infrared : the laser power falls down to zero at some particular wavelengths, whatever the beam adjustments are. We showed that this effect is related to to the waveguiding effect of the vacuum chamber leading to different losses and power outcoupling at different wavelengths*. To alleviate this effect we have designed a new undulator allowing to use a larger vacuum chamber without reducing the spectral tunability and agility of the FEL. From simulations, a large increase of available power is expected in far-infrared. The new undulator has been installed and its performances and first FEL measurement in far-infrared will be presented J.M. Ortega, F. Glotin, R. Prazeres Infrared Physics and Technology, 49, 133 (2006) ** R. Prazeres, F. Glotin, J.-M. Ortega Phys. Rev. STAB12, 010701 (2009)

TUPPP050	FEL Performances of the French LUNEX5 Project	laser, electron, bunching, undulator	1712
	C. Evain, S. Bielawski PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France C. Benabderrahmane, M.-E. Couprie, C. Evain, M. Labat, A. Loulergue SOLEIL, Gif-sur-Yvette, France G. Lambert, A. Lifschitz, V. Malka LOA, Palaiseau, France
	LUNEX5 is a french FEL test facility project based on two types of accelerators: a 400 MeV Conventional Linear Accelerator (CLA) and a Laser WakeField Accelerator (LWFA). The FEL performances will be presented at 20 nm and at 12 nm, wavelengths of interest for the pilot experiments. Results are obtained with GENESIS simulations in time-dependent mode. With the CLA, we compare different seeded schemes as EEHG scheme (Echo Enabled Harmonic Generation) or HGHG scheme (High Gain Harmonic Generation) using HHG source (High Harmonic in Gaz). In parallel, LWFA FEL performances will be presented as a function of the electron bunch characteristics, in particular the bunch length and the energy-spread. The transport of the LWFA output beams into undulators which is found to be a critical issue will be also discussed.

TUPPP052	Status of FLASH	electron, photon, laser, undulator	1715
	K. Honkavaara, B. Faatz, J. Feldhaus, S. Schreiber, R. Treusch, M. Vogt DESY, Hamburg, Germany
	FLASH at DESY (Hamburg, Germany) is a free-electron laser user facility driven by a superconducting 1.25 GeV linac based on TESLA technology. During the 3rd user period from September 2010 to September 2011, totally 3740 hours of FEL radiation has been delivered to FEL experiments at more than 30 different wavelengths between 4.7 nm and 45 nm. In addition, beam time has been dedicated to general accelerator physics studies and developments related to the future projects like the European XFEL and the International Linear Collider. After a 3.5 months shutdown in autumn 2011 due to civil construction for a second undulator beamline - FLASH2 - and a following commissioning and study period, 2012 is mainly dedicated to FEL user experiments. This paper summarizes the operation status of the FLASH facility and gives also a short review of the accelerator studies carried out in 2011 and early 2012. The mid-term plans including FLASH2 are presented as well.

TUPPP054	RF Activation and Preliminary Beam Tests of the X-band Linearizer at the FERMI@Elettra FEL Project	klystron, linac, emittance, LLRF	1721
	G. D'Auria, S. Di Mitri, G. Penco, C. Serpico ELETTRA, Basovizza, Italy
	FERMI@Elettra is a fourth generation light source facility presently in commissioning at the Elettra Laboratory in Trieste, Italy. It is based on an S-band (3 GHz), 1.5 GeV normal conducting (NC) linac, that provides ultra short e-bunches with high peak current, using two stages of magnetic compression. To linearize the beam longitudinal phase space and to improve the compression process, a forth harmonic RF structure (12 GHz) has been installed downstream the first magnetic chicane. This paper reports the RF activation of the structure and the preliminary tests performed on the beam.

TUPPP056	Study of the Energy Chirp Effects on Seeded FEL Schemes at SDUV-FEL	electron, radiation, laser, undulator	1724
	C. Feng, D. Wang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	Seeded free-electron laser (FEL) schemes hold great promise for generation of high brilliant radiation with a narrow bandwidth. Analysis with the idealized electron beam with constant current and energy indicate that both the high-gain harmonic generation (HGHG) and the echo-enabled harmonic generation (EEHG) can produce Fourier-transform limited radiation pulses. However, residual energy variations due to nonlinearity of the accelerator or energy modulations due to microbunching instability will be unavoidable and may broaden the bandwidth of the seeded FEL. In this paper, we study the energy chirp effects on both the HGHG and EEHG schemes. Analytic and simulation calculations are presented and compared with the experimental data. Results show that the coherence properties of the EEHG FEL may not be degraded by the energy chirp when properly choosing the parameters of the dispersion sections.

TUPPP057	Design of a Wavelength Continuously Tunable Ultraviolet Coherent Light Source	laser, radiation, simulation, undulator	1727
	T. Zhang, D. Wang, Z.T. Zhao SINAP, Shanghai, People's Republic of China X.M. Yang DICP, Dalian, People's Republic of China
	Funding: Work supported by National Natural Science Foundation of China (Grant No. 11075199) Dalian Coherent Light Source (DCL) is a proposed FEL-based novel light source user facility, will be located in Dalian city, China. DCL will mainly servers on the field of molecular reaction dynamics, ultra-fast physical chemistry experiments, etc. Running on the High-Gain-Harmonic-Generation (HGHG) FEL mode, DCL is expected to cover the FEL wavelength from 50 nm to 150 nm, with the help of continuously tuning Optical Parametric Amplification (OPA) seed laser system, which wavelength can be varied between 240 nm and 360 nm. Numerical simulation shows that the FEL pulse energy of DCL can surpass 100 μJ, at the whole full range wavelength with the undulator tapering technology, and the photon number can be up to 10¹³ per pulse, which is sufficient for user experiments.

TUPPP059	Effects of Metal Mirrors Reflectivity and Aberrations on THz FEL Radiation Performance	cavity, radiation, undulator, electron	1729
	P. Tan, T. Yu HUST, Wuhan, People's Republic of China M. Fan, Q. Fu, D. Li, B. Qin, Y.Q. Xiong, Y.B. Yibin Huazhong University of Science and Technology (HUST), Wuhan, People's Republic of China
	The primary design study of terahertz free-electron laser (FEL) is presented in this paper. The effects of optical cavity parameter, metal mirrors reflectivity and aberrations on the THz FEL radiation performance have been explored. The reflectivity characteristics of copper, silver and gold are tested in terahertz region. The effects of metal mirrors reflectivity and aberrations on the THz FEL radiation performance are studied by numerical simulation.

TUPPP061	Status of the PAL-XFEL Project	undulator, linac, gun, electron	1735
	J.H. Han, H.-S. Kang, I.S. Ko PAL, Pohang, Kyungbuk, Republic of Korea
	Funding: The Ministry of Education, Science and Technology of the Korean Government PAL-XFEL is designed to generate X-ray radiation in the range of 0.1 and 10 nm for users. The machine consists of a 10 GeV linear accelerator and five undulator beamlines. Electron beams are generated at a low emittance S-band photocathode RF gun and accelerated with an S-band normal conducting linac. Three hard X-ray beamlines will be located at the end of the linac. Electron beams for two soft X-ray beamlines will be switched at a medium energy. The project started in 2011 and the building construction is ongoing. Resent progress of the project and an update of the current progress are presented.

TUPPP062	Start to End Simulation of Three Bunch Compressor Lattice for PAL XFEL	lattice, emittance, linac, simulation	1738
	H.-S. Kang, M.-H. Cho, J.H. Han, T.-H. Kang, I.S. Ko PAL, Pohang, Kyungbuk, Republic of Korea C.H. Yi POSTECH, Pohang, Kyungbuk, Republic of Korea
	The PAL XFEL is a 0.1-nm hard X-ray FEL project starting from 2011 to finish in 2014, which aims at achieving higher photon flux than 10¹² photons/pulse at 0.1 nm using a 10 GeV electron linac. The PAL XFEL is designed to have a hard x-ray undulator line at the end of linac and a branch line at 2.65 GeV point for soft X-ray undulator line. The three bunch compressor lattice (3-BC) is chosen to minimize emitance growth due to CSR and minimize correlated energy spread. The 3-BC lattice makes it possible to operate soft X-ray FEL undulator line simultaneously and independently from hard X-ray FEL undulator line.

TUPPP064	Microbunching Instability Studies in SwissFEL	simulation, laser, booster, linac	1744
	S. Bettoni, B. Beutner Paul Scherrer Institut, Villigen, Switzerland V.A. Goryashko NASU/IRE, Kharkov, Ukraine
	Shot noise or an initial intensity modulation in the beam pulse may have a strong effect in the FEL linacs and also severely degrade the machine performances in terms of FEL performances. In this paper we present the simulations done to study this effect in SwissFEL, the future free electron laser under design at Paul Scherrer Institute. In particular we calculated the gain of the microbunching instability in the low and high energy part and we performed start-to-end simulations using as initial distribution something as close as possible to the laser profile measured at the SwissFEL injector test facility. We finally present the preliminary calculations to estimate the effect of the laser heater to mitigate this effect.

TUPPP066	CLARA - A Proposed New FEL Test Facility for the UK	electron, laser, undulator, diagnostics	1750
	J.A. Clarke, D. Angal-Kalinin, D.J. Dunning, S.P. Jamison, J.K. Jones, J.W. McKenzie, B.L. Militsyn, N. Thompson, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom R. Bartolini JAI, Oxford, United Kingdom I.P.S. Martin Diamond, Oxfordshire, United Kingdom
	A new single pass national FEL test facility, CLARA, is proposed to be constructed at Daresbury Laboratory in the UK. The aim of CLARA is to develop a normal conducting test accelerator able to generate longitudinally and transversely bright electron bunches and to use these bunches in the experimental production of stable, synchronized, ultra short photon pulses of coherent light from a single pass FEL with techniques directly applicable to the future generation of light source facilities. In addition the facility will be an ideal test bed for demonstrating innovative technologies such as high repetition rate normal conducting RF linacs and advanced undulator designs. This paper will describe the design of CLARA, pointing out the flexible features that will be incorporated to allow multiple novel FEL schemes to be proven.

TUPPP068	Comparison of Compression Schemes for CLARA	emittance, linac, sextupole, cavity	1756
	P.H. Williams, J.W. McKenzie STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom J.K. Jones, P.H. Williams Cockcroft Institute, Warrington, Cheshire, United Kingdom
	CLARA (Compact Linear Advanced Research Accelerator) at Daresbury Laboratory is proposed to be the UK’s national FEL test facility. The accelerator will be a ~250 MeV electron linac capable of producing short, high brightness electron bunches. The machine comprises a 2.5 cell RF photocathode gun, one 2 m and three 5 m normal conducting S-band (2998MHz) accelerating structures and a variable magnetic compression chicane. CLARA will be used as a test bed for novel FEL configurations. We present a comparison of acceleration and compression schemes for the candidate machine layout.

TUPPP069	A Compact, Modular Electron Beam Delay Line for Use in Novel Free-Electron Laser Schemes	undulator, quadrupole, electron, lattice	1759
	J.K. Jones, J.A. Clarke, N. Thompson STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Two Free-Electron Laser (FEL) schemes have been proposed, for the generation of attosecond pulse trains* and for the improvement of the longitudinal coherence of SASE FELs*, in which repeated electron delays are implemented within the undulator lattice. To obtain the maximum performance and flexibility from these schemes it is advantageous to use an electron delay line that satisfies the isochronicity conditions, as well as being compact, modular and, ideally, variable. In this paper we present initial designs for such a system, along with simulations of its performance. We investigate both in-undulator and out-of-undulator designs, and compare the applicability of each for various aspects of the FEL design, as well as commenting on the mechanical and magnetic implications of the schemes. N.R. Thompson and B.W.J. McNeil. Phys. Rev. Lett. 100, 203901 (2008). ** N.R. Thompson, D.J. Dunning and B.W.J. McNeil, IPAC2010, TUPE050, p. 2257 (2010).

TUPPP070	Next Generation Light Source R&D and Design Studies at LBNL	linac, electron, laser, gun	1762
	J.N. Corlett, B. Austin, K.M. Baptiste, D.L. Bowring, J.M. Byrd, S. De Santis, P. Denes, R.J. Donahue, L.R. Doolittle, P. Emma, D. Filippetto, G. Huang, T. Koettig, S. Kwiatkowski, D. Li, T.P. Lou, H. Nishimura, H.A. Padmore, C. F. Papadopoulos, G.C. Pappas, G. Penn, M. Placidi, S. Prestemon, D. Prosnitz, J. Qiang, A. Ratti, M.W. Reinsch, D. Robin, F. Sannibale, D. Schlueter, R.W. Schoenlein, J.W. Staples, C. Steier, C. Sun, T. Vecchione, M. Venturini, W. Wan, R.P. Wells, R.B. Wilcox, J.S. Wurtele LBNL, Berkeley, California, USA
	Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. LBNL is developing design concepts for a multi-beamline soft x-ray FEL array powered by a superconducting linear accelerator, operating with a high bunch repetition rate of approximately one MHz. The cw superconducting linear accelerator is supplied by an injector based on a high-brightness, high-repetition-rate photocathode electron gun. Electron bunches are distributed from the linac to the array of independently configurable FEL beamlines with nominal bunch rates up to 100 kHz in each FEL, and with even pulse spacing. Individual FELs may be configured for different modes of operation, and each may produce high peak and average brightness x-rays with a flexible pulse format, and with pulse durations ranging from sub-femtoseconds to hundreds of femtoseconds. In this paper we describe conceptual design studies and optimizations. We describe recent developments in the design and performance parameters, and progress in R&D activities.

TUPPP071	Design Concepts of a Beam Spreader for a Next Generation Free Electron Laser	electron, kicker, septum, linac	1765
	M. Placidi, P. Emma, J.-Y. Jung, G.C. Pappas, D. Robin, C. Sun, W. Wan LBNL, Berkeley, California, USA
	LBNL is developing design concepts for a multi-beamline soft x-ray FEL array powered by a superconducting linear accelerator, operating with a high bunch repetition rate of approximately one MHz. Electron bunches are distributed from the linac to the array (up to 10) independently configurable FEL beamlines with nominal bunch rates up to 100 kHz in each FEL, and with even pulse spacing. This distribution to the different FELs is made by the beam spreader for which the design has to relative compact while not significantly perturbing the quality of the electron beam and subsequent performance of the FELs. We report on our conceptual design for the spreader. The spreader lattice has two distinct parts, namely the beam take-off section and the FEL fan-out distributions section. Each section is achromatic and isochronous. The effect of coherent synchrotron radiation and micro-bunching has been studied when passing through the spreader and simulations show no significant deterioration in the beam quality.

TUPPP073	Machine Parameter Studies for an FEL Facility Using STAFF	photon, undulator, linac, emittance	1768
	M.W. Reinsch, B. Austin, J.N. Corlett, L.R. Doolittle, P. Emma, G. Penn, D. Prosnitz, J. Qiang, A. Sessler, M. Venturini LBNL, Berkeley, California, USA J.S. Wurtele UCB, Berkeley, California, USA
	Designing an FEL facility requires balancing multiple science needs, FEL and accelerator physics constraints, and engineering limitations. STAFF (System Trade Analysis for an FEL Facility) is a MATLAB program that enables the user to rapidly explore a large range of Linac and FEL design options to meet science requirements. The code uses analytical models such as the Ming Xie formulas when appropriate and look-up tables when necessary to maintain speed and flexibility. STAFF's modular design simplifies the inclusion of new physics models for FEL harmonics, wake fields, cavity higher-order modes and aspects of linac design such as the optimization of a laser heater, harmonic linearizer, and one or more bunch compressors. Code for the microbunching instability has been included as well. STAFF also supports multiple undulator technologies. STAFF permits the user to study error tolerances and multiple beamlines so as to explore the full capabilities of an entire user facility. This makes it possible to optimize the integrated system in terms of performance metrics such as photons/pulse, photons/sec and tunability range.

TUPPP074	Beam Dynamics Studies of a High-repetition Rate Linac Driver for a 4th-generation Light Source	emittance, simulation, linac, laser	1771
	M. Venturini, J.N. Corlett, P. Emma, C. F. Papadopoulos, G. Penn, M. Placidi, J. Qiang, M.W. Reinsch, F. Sannibale, C. Steier, R.P. Wells LBNL, Berkeley, California, USA
	We present progress toward the design of a super-conducting linac driver of a high repetition rate FEL-based soft x-ray light source. The machine is intended to accept beams generated by the APEX* photocathode gun, operating in the MHz range, and deliver them to an array of SASE and seeded FEL beamlines. After reviewing the beam-dynamics considerations that are informing specific lattice choices we discuss the expected performance of the proposed machine design and its ability to meet the desired FEL specifications. We consider the merit of possible alternate designs (e.g., a one-stage compressor vs. a two-stage compressor) and the trade-offs between competing demands on the beam attributes (e.g., high peak current vs. acceptable energy spread). * F. Sannibale et al., this conference.

TUPPP076	Soft Orbit Bumps for Duke Storage Ring VUV FEL Operation	radiation, wiggler, electron, dipole	1774
	S.F. Mikhailov, J.Y. Li, V. Popov, P.W. Wallace, Y.K. Wu FEL/Duke University, Durham, North Carolina, USA
	Funding: This work is supported in part by the US DoE grant # DE-FG02-97ER41033. The Duke FEL and High Intensity Gamma-ray Source (HIGS) facility is operated with an electron beam from 0.24 to 1.2 GeV and a photon beam from 190 to 1060 nm. The current range of the gamma-beam energy is from 1 MeV to about 100 MeV, with the maximum total gamma-flux of more then 10¹⁰ gammas per second around 10 MeV. Production of the high intensity, high energy gamma-beams of 60-100 MeV using UV-VUV mirrors of 240 - 190 nm requires and high energy, high current electron beams of 0.9-1.05 GeV. The radiation damage problem becomes more severe for VUV FEL operation below 190 nm. The radiation from the End-of-Arc (EOA) bending magnets, instead of the radiation from FEL wigglers, is the dominant cause of a rapid degradation of the downstream FEL mirror. In this work, we propose a number of measures to significantly reduce the radiation from these dipole magnets as well as other potential sources of synchrotron radiation toward the FEL mirror. In particular, we describe the development of an orbit bump using designated "soft" orbit correctors. The magnetic field of these correctors is limited to produce a radiation with a critical wavelength close or below the FEL wavelength.

TUPPP079	Design Alternatives for a Free Electron Laser Facility	linac, undulator, electron, photon	1777
	K. Jacobs, J. Bisognano, R.A. Bosch, D. Eisert, M.V. Fisher, M.A. Green, R.G. Keil, K.J. Kleman, J.G. Kulpin, G.C. Rogers, R. Wehlitz UW-Madison/SRC, Madison, Wisconsin, USA T. Chiang, T.J. Miller University of Illinois, Urbana, USA J.E. Lawler, D. Yavuz UW-Madison/PD, Madison, Wisconsin, USA R.A. Legg JLAB, Newport News, Virginia, USA R.C. York FRIB, East Lansing, Michigan, USA
	The University of Wisconsin-Madison is continuing design efforts for a vacuum ultraviolet/X-ray Free Electron Laser facility. The design incorporates seeding the FEL to provide fully coherent photon output at energies up to ~1 keV. The focus of the present work is to minimize the cost of the facility while preserving its performance. To achieve this we are exploring variations in the electron beam driver for the FEL, in undulator design, and in the seeding mechanism. Design optimizations and trade-offs between the various technologies and how they affect the FEL scientific program will be presented.

TUPPP082	Optimization of a Terawatt Free Electron Laser	undulator, electron, radiation, focusing	1780
	J. Wu, X. Huang, Y. Jiao, A.U. Mandlekar, T.O. Raubenheimer, S. Spampinati, G. Yu SLAC, Menlo Park, California, USA P. Chu FRIB, East Lansing, Michigan, USA J. Qiang LBNL, Berkeley, California, USA
	Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515. There is great interest in generating a terawatt (TW) hard X-ray free electron laser (FEL) that will enable coherent diffraction imaging of complex molecules like proteins and probe fundamental high-field physics. A feasibility study of producing such pulses was carried out em- ploying a configuration beginning with an SASE amplifier, followed by a "self-seeding" crystal monochromator, and finishing with a long tapered undulator. The undulator tapering profile, the phase advance in the undulator break sections, the quadrupole focusing strength, etc. are parameters to be optimized. A genetic algorithm (GA) is adopted for this multi-dimensional optimization. Concrete examples are given for LCLS/LCLS-II systems.

TUPPP083	Multi-Dimensional Optimization of a Tapered Free Electron Laser	undulator, radiation, electron, focusing	1783
	Y. Jiao, J. Wu SLAC, Menlo Park, California, USA Q. Qin IHEP, Beijing, People's Republic of China
	Energy extraction efficiency of a free electron laser (FEL) can be increased when the undulator is tapered. In this paper, we report a multi-dimensional optimizer to maximize the radiation power in a tapered FEL by searching for an optimal taper profile as well as a reasonable variation in electron beam radius. Applications of the proposed multi-dimensional optimization to the terawatt-level, tapered FELs with LCLS-like electron beam parameters are presented, and the proposed optimization scheme is compared with the GINGER’s self-design taper algorithm. At the end, the dependence of the available maximum radiation power on various parameters of the initial electron beam, the initial radiation field and the undulator system is summarized.

TUPPP084	Efficiency Enhancement in a Tapered Free Electron Laser by Varying the Electron Beam Radius	electron, radiation, undulator, simulation	1786
	Y. Jiao, J. Wu SLAC, Menlo Park, California, USA Q. Qin IHEP, Beijing, People's Republic of China
	Energy extraction efficiency of a free electron laser (FEL) can be increased when the undulator is tapered. An in-depth understanding of the tapering-related physics is required to explore the full potential of a tapered FEL, not only by tapering the undulator parameters in longitudinal dimension, but also optimizing the transverse effects. Based on the modified 1D FEL model and time-steady numerical simulations, we study the contribution of the variation in electron beam radius and the related transverse effects. Taking a terawatt-level, 120-m tapered FEL as example, we demonstrate that a reasonably varied, instead of a constant, electron beam radius along the undulator helps to improve the optical guiding and thus the radiation output.

TUPPP086	A Synchronized FIR/VUV Light Source at Jefferson Lab	laser, wiggler, electron, coupling	1789
	S.V. Benson, D. Douglas, G. Neil, M.D. Shinn, G.P. Williams JLAB, Newport News, Virginia, USA
	Funding: This work was supported by U.S. DOE Contract No. DE-AC05-84-ER40150, the Air Force Office of Scientific Research, DOE Basic Energy Sciences. We describe a dual FEL configuration on the UV Demo FEL at Jefferson Lab that would allow simultaneous lasing at THz and UV wavelengths. The THz source would be an FEL oscillator with a short wiggler providing diffraction-limited pulses with pulse energy exceeding 50 microJoules. The THz source would use the exhaust beam from a UVFEL. The coherent harmonics in the VUV from the UVFEL are outcoupled through a hole. The THz source uses a shorter resonator with either hole or edge coupling to provide very high power THz pulses. Simulations indicate excellent spectral brightness in the THz region with over 100 W/cm^-1 output.

TUPPP087	Commissioning of the Fritz Haber Institute Mid-IR FEL	wiggler, electron, linac, undulator	1792
	A.M.M. Todd, H. Bluem, D. Dowell, R. Lange, J.H. Park, J. Rathke, L.M. Young AES, Princeton, New Jersey, USA W. Erlebach, S. Gewinner, H. Junkes, A. Liedke, G. Meijer, W. Schöllkopf, W.Q. Zhang, G. von Helden FHI, Berlin, Germany S.C. Gottschalk STI, Washington, USA K. Jordan Kevin Jordan PE, Newport News, Virginia, USA U. Lehnert, P. Michel, W. Seidel HZDR, Dresden, Germany R. Wünsch FZD, Dresden, Germany
	The IR and THz FEL at the Fritz Haber Institute (FHI) in Berlin is designed to deliver radiation from 4 to 400 microns. A single-plane-focusing undulator combined with a 5.4-m-long cavity is used is the mid-IR (< 50 micron), while a two-plane-focusing undulator in combination with a 7.2-m-long cavity with a 1-D waveguide for the optical mode is planned for the far-IR. Beam was delivered to the IR beam dump in November 2011. We describe progress since that time in completing the commissioning of the mid-IR beamline and the status of the far-IR beamline design and fabrication.

TUPPP088	Bunch Compressor Design for Potential FEL Operation at eRHIC	emittance, electron, simulation, linac	1795
	Y.C. Jing, Y. Hao, V. Litvinenko BNL, Upton, Long Island, New York, USA
	Electron-Relativistic Heavy Ion Collider (eRHIC) is an upgrade project for the current operation of RHIC. It will provide a high quality electron beam with energy recovery scheme to collide with ion beams. One may think of taking advantage of using this electron beam for FEL operation. Bunch compressor is a crucial component to compress the beam to high peak current for undulators and CSR effect needs to be taken care of to preserve the beam quality. In this paper, authors present a novel bunch compressor design with CSR suppression scheme for the potential FEL operation at eRHIC.

TUPPP093	General Results on the Nature of FEL Amplification	electron, laser, free-electron-laser, wiggler	1804
	S.D. Webb Tech-X, Boulder, Colorado, USA V. Litvinenko, G. Wang BNL, Upton, Long Island, New York, USA
	Free-electron lasers are increasingly important tools for the material and biological sciences, and although numerical and analytical theory is extensive, a fundamental question about the nature of the FEL growing modes has remained unanswered. In this proceeding, we present results of a topological nature concerning the number of amplifying solutions to the 1-dimensional FEL equations as related to the energy distribution of the electron bunches.

WEXB01	Recent Advances and New Techniques in Visualization of Ultra-short Relativistic Electron Bunches	radiation, electron, laser, RF-structure	2091
	D. Xiang SLAC, Menlo Park, California, USA
	Funding: Work supported by U.S. DOE under Contract No. DE-AC02-76SF00515. This talk will address advances in the measurement of ultra-short relativistic bunches at femtosecond frontier in high-energy x-ray free-electron lasers (FELs). In general, this presentation will discuss several recently proposed novel techniques (i.e. mapping z exactly to delta * and x , optical oscilloscope , etc.) that are capable of breaking the femtosecond time barrier in measurements of ultrashort bunches. In particular, this presentation will report on the all-optical, time-resolved method to probe beam longitudinal phase space with femtosecond time scale and 10^-5 energy scale resolution *. The simultaneous measurement of temporal profile and beam slice energy spread after the FEL interaction is also shown to reveal the time-dependent x-ray radiation profile **. Z. Huang et al., PRSTAB 13, 092801. D. Xiang, Y. Ding, PRSTAB 13, 094001. * G. Andonian et al., PRSTAB 14, 072802. ** D. Xiang et al., PRSTAB 14, 112801. *** Y. Ding et al., FEL11.
	Slides WEXB01 [6.873 MB]

WEYB01	The SPring-8 Angstrom Compact Free Electron Laser (SACLA)	laser, electron, emittance, undulator	2106
	H. Tanaka RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan
	Commissioning of the world's first compact X-ray FEL facility named SPring-8 Angstrom Compact free electron LAser (SACLA) began in the Spring of 2011 and soon demonstrated lasing at a wavelength of 0.12nm. In the autumn of 2011 laser intensity reached sub mJ/pulse in the wavelengths ranging from 0.1 to 0.3 nm. The laser power saturation was also achieved at around or longer than 0.1 nm. The official user operation will start from March 2012. This presentation will cover innovative design aspects of the SACLA construction project, events leading to key milestones in the commissioning process, a review of the present status and perspectives on future upgrades.
	Slides WEYB01 [13.170 MB]

WEYB03	High Average Power UV Free Electron Laser Experiments at JLAB	wiggler, cavity, linac, electron	2111
	D. Douglas, S.V. Benson, P. Evtushenko, J.G. Gubeli, C. Hernandez-Garcia, R.A. Legg, G. Neil, T. Powers, M.D. Shinn, C. Tennant, G.P. Williams JLAB, Newport News, Virginia, USA
	Funding: Authored by JSA LLC under US DOE Contract #DE-AC05-06OR23177. The U.S. Gov. retains non-exclusive, paid-up, irrevocable, world-wide license to publish/reproduce this manuscript for U.S. Gov. purposes. Having produced 14 kW of average power at ~2 microns, JLAB has shifted its focus to the ultraviolet portion of the spectrum. This presentation will describe the JLab UV Demo FEL, present specifics of its driver ERL, and discuss the latest experimental results from FEL experiments and machine operations.
	Slides WEYB03 [2.863 MB]

WEOBB01	Measurement of the Local Energy Spread of Electron Beam at SDUV-FEL	laser, electron, bunching, radiation	2143
	C. Feng, J.H. Chen, H.X. Deng, T. Lan, B. Liu, D. Wang, X. Wang, M. Zhang, T. Zhang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	The slice energy spread of electron beam is a very important parameter for high gain free electron lasers (FELs) especially the seeded FELs. Because of its extremely small value, highly accurate measurement of the slice energy spread is rather challenging. In this paper, we propose a novel method to accurately measure the slice energy spread based on the coherent harmonic generation (CHG) scheme. This method has been demonstrated on the Shanghai deep ultraviolent FEL (SDUV-FEL), and the results show that the slice energy spread is about only 1.2keV at the exit of the 136MeV linac when the bunch compressor is off, and this value change to about 2.6keV when the bunch compressor is on. * Chao Feng, et al, Phys. Rev. ST Accel. Beams 14, 090701 (2011)
	Slides WEOBB01 [3.309 MB]

WEIC04	Functional Materials Development using Accelerator-based Light Sources: Current Capabilities and Future Prospects	controls, synchrotron, electron, radiation	2156
	W.R. Flavell UMAN, Manchester, United Kingdom
	Funding: UK Engineering and Physical Sciences Research Council (EPSRC), UK Science and Technology Facilities Council (STFC) The development of accelerator-based light sources has allowed access to photons of very high brightness and wide tunability. These properties of synchrotron radiation (SR) mean that it can be used to resolve questions that can be answered in no other way, enabling unique contributions to the development of functional materials. Increasingly, these benefits have become essential to material evaluation in manufacturing – ranging from intelligent catalysts for automotive emissions control* to next generation photovoltaics. Bright, tunable X-rays have been a boon to nanotechnology* in particular, with its requirement for atom-by-atom understanding – and this benefit is enhanced by the microfabrication capabilities of X-ray lithography in LIGA-based techniques. The result is unique potential for nanoscale device manufacture. The application of bright tunable X-rays to the development of nanostructures for a range of industrial applications is illustrated, and the prospects for exploitation of the ultra-high brightness and femtosecond time structure of FEL radiation are discussed. * H Tanaka et al., Ang. Chemie Int. Ed. 45, 5998 (2006) S J O Hardman et al., Phys Chem Chem Phys 13, 20275 (2011) * S Biswas et al., Small (2012) DOI: 10.10⁰²/smll201102100
	Slides WEIC04 [11.723 MB]

WEPPD049	Characterization of the Engineered Photodiode-based Fiber Link Stabilization Scheme for Optical Synchronization Systems	laser, LLRF, optics, controls	2627
	T. Lamb, M.K. Bock, M. Felber, F. Ludwig, H. Schlarb, S. Schulz DESY, Hamburg, Germany S. Jabłoński Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
	Pulsed optical synchronization systems are used in modern FELs like FLASH and will be used in the upcoming European XFEL. Their purpose is to distribute synchronization signals with femtosecond stability throughout the machine. Optical fibers are used to transport the pulses carrying the timing information to their end-stations. These fibers have to be continuously delay stabilized in order to achieve the desired precision. In this paper, a photodiode-based detector to measure the drifts of the fiber delay and allows their active correction is presented. Promising results from a first prototype setup of a photodiode-stabilized optical fiber link were the starting point for an engineering of this concept. An enclosure with free-space optics, fiber optics and integrated electronics for the detector, operating at 9.75 GHz, was designed. This unit includes all required parts to stabilize four fiber links. It allows to investigate the temperature sensitivity of the detector. Furthermore, results from drift measurements carried out with a two channel engineered detector are presented in this paper.

WEPPD076	A Fast Kicker for a Staged Dielectric Two-beam Wakefield Accelerator	kicker, wakefield, cavity, klystron	2702
	J.G. Power, M.E. Conde, W. Gai ANL, Argonne, USA C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA
	Funding: Work supported by DoE, Office of HEP. An experimental program to demonstrate staging in a dielectric two-beam wakefield accelerator (dielectric TBA) is being planned at the Argonne Wakefield Accelerator (AWA) facility. We are planning an experiment that both fits in the AWA tunnel and mimics conditions similar to the recently presented conceptual design of a linear collider based on the dielectric TBA. This conceptual design is based on a new parameter space of the TBA scheme utilizing an ultra-short (~20ns) rf pulse in a dielectric TBA. The decelerating structures are driven by a series of drive microbunch trains that are 20 ns in duration and separated by 100 ns. This means that the fast kicker must have an extremely quick risetime as well as become stable within about 50 ns. In this paper, we consider designs for a fast kicker based on RF deflecting cavities and stripline kickers.

WEPPP040	Progress Report on Development of Novel Ultrafast Mid-IR Laser System	laser, acceleration, wakefield, background	2810
	R. Tikhoplav, A.Y. Murokh RadiaBeam, Santa Monica, USA I. Jovanovic Penn State University, University Park, Pennsylvania, USA
	Finding alternate acceleration mechanisms that can provide very high gradients is of particular interest to the accelerator community. Those mechanisms are often based on either dielectric laser acceleration or laser wakefield acceleration techniques, which would greatly benefit from mid-IR ultrafast high peak power laser systems. The approach of this proposed work is to design a novel ultrafast mid-IR laser system based on optical parametric chirped-pulse amplification (OPCPA). OPCPA is a technique ideally suited for production of ultrashort laser pulses at the center wavelength of 2μm-5μm. Some of the key features of OPCPA are the wavelength agility, broad spectral bandwidth and negligible thermal load. This paper reports on the progress of the development of the ultrafast mid-IR laser system.

WEPPP073	Dynamic Feedback Model for High Repetition Rate Linac-driven FELs	linac, feedback, cavity, beam-loading	2879
	J.M. Byrd, L.R. Doolittle, P. Emma, G. Huang, A. Ratti, C. Serrano LBNL, Berkeley, California, USA
	Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. One of the concepts for the next generation of linac-driven FELs is a cw superconducting linac driving an electron beam with MHz repetition rates. One of the challenges for next generation FELs is improve the shot-to-shot stability of the energy, charge, peak current, and timing jitter of the electron beam. The use of a cw RF system with MHz beam repetition rates presents an opportunity to use broadband feedback to stabilize the beam parameters. To understand the performance of such a feedback system, we are are developing a dynamic feedback model of the machine with a focus on the longitudinal beam properties. The model is being developed as an extension of the LITrack code and will include the dynamics of the beam-cavity interaction, RF feedback, beam-based feedback, and multibunch effects. In this paper, we will present the status of this model along with results.

WEPPR064	Very Short Range Wake in Strongly Tapered Disk Loaded Waveguide Structures	simulation, wakefield, linac, impedance	3072
	A. Grudiev CERN, Geneva, Switzerland
	Electron bunches are very short, both in linear collider and in X-FEL projects. Furthermore, typical disk-loaded waveguide structures used for particle acceleration are tapered. For example in CLIC, in order to achieve high accelerating gradient, the structure is only 26 cells long, which results in strong tapering. In this paper, very short range wake is investigated in the regime where the number of cells needed to arrive at steady state is much larger than the number of cells in a single tapered structure. In this case the very short range wake is dominated by the wake from the smallest aperture. The results of an analytical model and numeric solutions are compared.

THYB02	Influence of Electron Beam Parameters on Coherent Electron Cooling	electron, ion, acceleration, radiation	3213
	G. Wang, Y. Hao BNL, Upton, Long Island, New York, USA V. Litvinenko Stony Brook University, Stony Brook, USA S.D. Webb Tech-X, Boulder, Colorado, USA
	Coherent electron cooling (CeC) is promising to revolutionize the cooling of high energy hadron beams. The intricate dynamics of the CeC depends both on the local density and energy distribution of the beam. This talk should present a rigorous analytical model of the 3D processes (including diffraction) in the modulator and the FEL and describe how the theory is applied to electron beams with inhomogeneous longitudinal density- and energy distributions in the process of CeC. The SPC would like you to describe the influence of electron beam energy and current variations along the bunch length.
	Slides THYB02 [0.878 MB]

THPPC054	Installation and Tests of the X-Band Power Plant for the FERMI@Elettra Project	klystron, vacuum, LLRF, power-supply	3410
	G. D'Auria, P. Delgiusto, F. Gelmetti, M.M. Milloch, A. Milocco, F. Pribaz, C. Serpico, N. Sodomaco, M. Svandrlik, R. Umer, L. Veljak ELETTRA, Basovizza, Italy
	FERMI@Elettra, the fourth generation light source facility at the Elettra Laboratory in Trieste, Italy, foresees an X-band accelerating section downstream the first bunch compressor to linearize the beam longitudinal phase space. The RF power for the structure is produced by the SLAC XL5 klystron, a scaled version of the XL4 tube, operating at the European frequency of 11.992 GHz. The 50 Hz klystron modulator is based on a standard pulse forming network (PFN) design, with thyratron and pulse transformer, for which there is already an extensive experience at the Elettra laboratory. We report about the installation and tests of the first high power RF station.

THPPC058	S-band Low-level RF System for 10 GeV PAL-XFEL	LLRF, klystron, controls, linac	3422
	W.H. Hwang, J.Y. Huang, H.-S. Kang, H.-S. Lee, W.W. Lee PAL, Pohang, Kyungbuk, Republic of Korea
	In PAL, We are constructing a 10GeV PxFEL project. The output power of the klystron is 80 MW at the pulse width of 4 ㎲ and the repetition rate of 120 Hz. And the specifications of the rf phase and amplitude stability are 0.05 degrees(rms) and 0.01%(rms) respectively. We achieved the stability of 0.03 degrees(p-p) at low power rf output using a phase amplitude detection system(PAD) and phase amplitude control(PAC) system. This paper describes the microwave system and the PAD and PAC system for the PxFEL.

THPPD008	Status of the PAL-XFEL Undulator System	undulator, controls, status, dipole	3509
	D.E. Kim, H.S. Han, Y.-G. Jung, H.-G. Lee, W.W. Lee, K.-H. Park, H.S. Suh PAL, Pohang, Kyungbuk, Republic of Korea J. Pflüger European XFEL GmbH, Hamburg, Germany
	Funding: Work supported by POSCO and MEST of Korea. Pohang Accelerator Laboratory (PAL) is developing 10 GeV, 0.1 nm SASE based FEL for high power, short pulse X-ray coherent photon sources named PAL-XFEL. At the first stage PAL-XFEL needs two undulator lines for photon source. PAL is developing undulator magnetic structure based on EU-XFEL design. The hard Xray undulator features 7.2 mm min magnetic gap, and 5.0 m magnetic length with maximum effective magnetic field larger than 0.908 T to achieve 0.1nm radiation at 10 GeV electron energy. In this report, we discuss the status of the hard X-ray undulator and soft X-ray undulator designs.

THPPD044	Fabrication and Testing of Curved Test Coil for FRIB Fragment Separator Dipole	dipole, radiation, quadrupole, proton	3611
	S.A. Kahn Muons, Inc, Batavia, USA J. Escallier, R.C. Gupta, G. Jochen, Y. Shiroyanagi BNL, Upton, Long Island, New York, USA
	Funding: Supported in part by SBIR Grant 4746 · 11SC06273 A critical element of the fragment separator region of the Facility for Rare Isotope Beams (FRIB) is the 30° dipole bend magnet. Because this magnet will be subjected to extremely high radiation and heat loads, operation at 4.5 K would not be possible. High temperature superconductors which have been shown to be radiation resistant and can operated in the 30-50 K temperature range which is more effective for heat removal. An efficient design for this magnet would make use of coils that follow the curvature of the magnet. Winding curved coils with negative curvature are difficult as the coil tends to unwind during the process. As part of an R&D effort for this magnet we are winding a ¼ scale test coil for this magnet with YBCO conductor and are testing it at 77 K. This paper will discuss the winding process and the test results of this study.

THPPP020	Project X with Superconducting Rapid Cycling Synchrotron	synchrotron, extraction, proton, beam-losses	3773
	H. Piekarz Fermilab, Batavia, USA
	A synchrotron-based upgrade of Fermilab accelerator complex for high intensity physics with Project X is described. It consists of: 1 GeV pulse linac, 1-8 GeV superconducting rapid cycling synchrotron (SRCS), dual 8 GeV storage ring (SR1,2), and 60 GeV Main Injector(MI). Pulse linac and SRCS operate at 10 Hz while SR1, SR2, and MI operate at 1.33 Hz. SR1 stores 3 and SR2 4 SRCS pulses making physics cycle 0.7 s. SR1 batch is extracted in 0.5 s at 3 locations of its ring providing beams to kaon and 2 muon experiments. SR2 batch is transferred to MI, accelerated to 60 GeV, and extracted to 3 neutrino production targets for Minos, Nova, and LBNE experiments. Main synchrotron parameters are listed and magnet systems described. Projected beam power is compared to expectations with linac-only based upgrade as well as with current and planned similar accelerator facilities elsewhere.

THPPR044	A New Electron Beam Test Facility (EBTF) at Daresbury Laboratory for Industrial Accelerator System Development	electron, gun, laser, vacuum	4074
	P.A. McIntosh, D. Angal-Kalinin, S.R. Buckley, J.A. Clarke, A.R. Goulden, C. Hill, S.P. Jamison, J.K. Jones, A. Kalinin, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, T.T. Ng, B.J.A. Shepherd, R.J. Smith, S.L. Smith, N. Thompson, A.E. Wheelhouse STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom N. Bliss, G.P. Diakun, A. Gleeson, T.J. Jones, B.G. Martlew, A.J. Moss, L. Nicholson, M.D. Roper, C.J. White STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	Recent UK government funding has facilitated the implementation of a unique accelerator test facility which can provide enabling infrastructures targeted for the development and testing of novel and compact accelerator technologies, specifically through partnership with industry and aimed at addressing applications for medicine, health, security, energy and industrial processing. The infrastructure provision on the Daresbury Science and Innovation Campus (DSIC) will permit research into areas of accelerator technologies which have the potential to revolutionise the cost, compactness and efficiency of such systems. The main element of the infrastructure will be a high performance and flexible electron beam injector facility, feeding customised state-of-the-art testing enclosures and associated support infrastructure. The facility operating parameters and implementation status will be described, along with primary areas of commercialised technology development opportunities.

FRYAP01	The Future of X-ray FELs	undulator, electron, laser, linac	4180
	H.-H. Braun Paul Scherrer Institut, Villigen, Switzerland
	Recent years have brought enormous progress with X-ray FELs. With LCLS and SACLA two facilities with quite different technological approaches have shown the feasibility of SASE FELs in the hard X-ray regime while the SASE FEL FLASH and the recently commissioned laser seeded FEL FERMI@ELETTRA provide coherent light beams of unprecedented brightness at EUV and soft X-ray wavelength. First user experiments at these facilities demonstrate the vast scientific potential of this new type of instrument and have accelerated and triggered R&D and planning for other facilities of its kind worldwide. Projects under construction or in advanced stage of planning are European XFEL, LCLS II, SwissFEL, PAL XFEL, Shanghai XFEL and NGLS. Worldwide R&D efforts for XFELs try to improve performance and reduce size and cost. Focuses are on injector, linac and undulator technologies as well as on FEL seeding methods.
	Slides FRYAP01 [24.324 MB]

Paper

Title

Other Keywords

Page

MOOAA02

Instrumentation and Diagnostics for High Repetition Rate Linac-driven FELs

linac, emittance, diagnostics, laser

23

J.M. Byrd, S. De Santis, L.R. Doolittle, D. Filippetto, G. Huang, M. Placidi, A. Ratti
LBNL, Berkeley, California, USA

Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
One of the concepts for the next generation of linac-driven FELs is a cw superconducting linac driving an electron beam with MHz repetition rates. The beam is then switched into an array of independently configurable FELs. The demand for high brightness beams and the high rep-rate presents a number of challenges for the instrumentation and diagnostics. The high rep-rate also presents opportunities for increased beam stability because of the ability for much higher sampling rates for beam-based feedbacks. In this paper, we present our plans for instrumentation and diagnostics for such a machine.

Slides MOOAA02 [1.710 MB]

MOOBC03

A Multi Purpose X Band Accelerating Structure

wakefield, linac, resonance, alignment

70

M.M. Dehler, A. Citterio, R. Zennaro
Paul Scherrer Institut, Villigen, Switzerland
G. D'Auria, C. Serpico
ELETTRA, Basovizza, Italy
D. Gudkov, A. Samoshkin
JINR, Dubna, Moscow Region, Russia
S. Lebet, G. Riddone, J. Shi
CERN, Geneva, Switzerland

In a collaboration between CERN, PSI and Sincrotrone Trieste (ST), a series of four multipurpose X-band accelerating structures has been designed and fabricated. The structures have 72 cells with a phase advance of 5 pi/6 and include upstream and downstream wakefield monitors to measure the beam alignment. We give an overview of the electrical and mechanical design and describe the fabrication of the first units. We also present the results of the low level RF tests. Using measurements of the internal cell to cell misalignment, the residual transverse wake and the noise floor of the wake field monitors are computed. Furthermore, we present the first experiences running the structures under high power.

Slides MOOBC03 [15.521 MB]

MOEPPB014

Time Jitter Measurements in Presence of a Magnetic Chicane in the FERMI@elettra Linac

electron, linac, laser, dipole

109

G. Penco, P. Craievich, S. Di Mitri, M.M. Milloch, F. Rossi
ELETTRA, Basovizza, Italy

Accurate and highly stable temporal synchronization between an electron bunch and a pulse from an external seed laser is one of the key requirements for successful operation of a seeded FEL in the XUV and soft x-ray regime. These requirements become more stringent when the electron bunch is longitudinally compressed to sub-ps durations in order to increase the current for more efficient FEL action. In this paper we present experimental measurements of the electron bunch arrival time jitter after the first magnetic compressor of FERMI@Elettra seeded FEL as a function of the compression factor. The experimental behavior of the pulse-to-pulse time jitter agrees both with results from tracking code simulations and with predictions from an analytical approach that takes into account the different sources of time jitter in FERMI, namely the photoinjector drive laser, the RF accelerating cavity phases and voltages, and fluctuations in the chicane bending magnet currents. We also present predictions for the expected arrival time jitter in the final configuration of FERMI that includes two bunch compressors and for which the synchronization requirement is of order 100 fs or better.

MOPPC090

Coupling Modulator Simulations into an FEL Amplifier for Coherent Electron Cooling

electron, simulation, radiation, positron

346

I.V. Pogorelov, G.I. Bell, D.L. Bruhwiler, B.T. Schwartz, S.D. Webb
Tech-X, Boulder, Colorado, USA
Y. Hao, V. Litvinenko, G. Wang
BNL, Upton, Long Island, New York, USA

Funding: Work supported by the US DOE Office of Science, Office of Nuclear Physics under grant numbers DE-FG02-08ER85182 and DE-SC0000835.
Next-generation ion colliders will require effective cooling of high-energy hadron beams. Coherent electron cooling (CeC) can in principle cool relativistic hadron beams on orders-of-magnitude shorter time scales than other techniques*. Particle-in-cell (PIC) simulations of a CeC modulator with the parallel VORPAL framework generate macro-particle distributions with subtle but important phase space correlations. To couple these macro-particles into a 3D simulation code for the free-electron laser (FEL) amplifier, while retaining all details of the 6D phase space coordinates, we implemented an alternative approach based on particle-clone pairs**. Our approach allows for self-consistent treatment of shot noise and spontaneous radiation, with no need for quiet-start initialization of the FEL macro-particles' ponderomotive phase. We present results of comparing fully 3D amplifier modeling based on the particle-clone approach vs GENESIS simulations where distribution of bunching parameter was used as input. We also discuss enabling direct coupling of the VORPAL delta-f simulation output into 3D distributions of particle-clone pairs.
* V.N. Litvinenko and Y.S. Derbenev, Phys. Rev. Lett. 102, 114801 (2009).
** V.N. Litvinenko, "Macro-particle FEL model with self-consistent spontaneous radiation," unpublished (2002).

MOPPD016

Status of Proof-of-principle Experiment for Coherent Electron Cooling

electron, gun, ion, wiggler

400

I. Pinayev, S.A. Belomestnykh, I. Ben-Zvi, J. Bengtsson, A. Elizarov, A.V. Fedotov, D.M. Gassner, Y. Hao, D. Kayran, V. Litvinenko, G.J. Mahler, W. Meng, T. Roser, B. Sheehy, R. Than, J.E. Tuozzolo, G. Wang, S.D. Webb, V. Yakimenko
BNL, Upton, Long Island, New York, USA
G.I. Bell, D.L. Bruhwiler, V.H. Ranjbar, B.T. Schwartz
Tech-X, Boulder, Colorado, USA
A. Hutton, G.A. Krafft, M. Poelker, R.A. Rimmer
JLAB, Newport News, Virginia, USA
M.A. Kholopov, P. Vobly
BINP SB RAS, Novosibirsk, Russia

Funding: US DOE Office of Science, DE-FC02-07ER41499, DE-FG02-08ER85182; NERSC DOE contract No. DE-AC02-05CH11231.
Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron colliders. To verify the concept we conduct proof-of-the-principle experiment at RHIC. In this paper, we describe the current experimental setup to be installed into 2 o’clock RHIC interaction regions. We present current design, status of equipment acquisition and estimates for the expected beam parameters.

MOPPD038

Simulation Study of Electron Response Amplification in Coherent Electron Cooling

electron, ion, bunching, undulator

448

Y. Hao, V. Litvinenko
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In Coherent Electron Cooling (CEC), it is essential to study the amplification of electron response to a single ion in the FEL process, in order to proper align the electron beam and the ion beam in the kicker to maximize the cooling effect. In this paper, we use Genesis to simulate the amplified electron beam response of single ion in FEL amplification process, which acts as 'Green function' of the FEL amplifier.

MOPPP012

Experimental Observation of Energy Modulation in Electron Beams Passing through Terahertz Dielectric Wakefield Structures

wakefield, bunching, radiation, acceleration

595

S.P. Antipov, C.-J. Jing, A. Kanareykin, P. Schoessow
Euclid TechLabs, LLC, Solon, Ohio, USA
M.G. Fedurin, K. Kusche, V. Yakimenko
BNL, Upton, Long Island, New York, USA
W. Gai, A. Zholents
ANL, Argonne, USA
B.C. Jiang
SINAP, Shanghai, People's Republic of China

Funding: DOE SBIR.
We report observation of a strong wakefield induced energy modulation in an energy-chirped electron bunch passing through a terahertz dielectric-lined waveguide. This modulation can be effectively converted into a spatial modulation by means of a chicane, forming micro-bunches (density modulation) with a periodicity of 0.5 - 1 picosecond, hence capable of driving coherent THz radiation. The experimental results agree well with theoretical predictions.

MOPPP013

Passive Momentum Spread Compensation by a “Wakefield Silencer”

wakefield, electron, dipole, simulation

598

S.P. Antipov, C.-J. Jing, A. Kanareykin, P. Schoessow
Euclid TechLabs, LLC, Solon, Ohio, USA
M.G. Fedurin, K. Kusche, V. Yakimenko
BNL, Upton, Long Island, New York, USA
W. Gai, A. Zholents
ANL, Argonne, USA

Funding: DOE SBIR.
We report an observation of de-chirping of a linearly chirped (in energy) electron bunch by its passage through a 5 cm long dielectric loaded waveguide structure. The experiment was conducted at the ATF facility at BNL according to a concept dubbed a wakefield silencer originally developed at the ANL AATF*, which involves defining the electron bunch peak current distribution and selecting the optimal waveguide structure suitable for chirp cancellation using self-induced wakefields of the electron bunch. Our experiment has been carried out with a 247 micron triangular beam with a 200 keV energy spread, which was reduced by a factor of three to approximately 70 keV by passing it through a 0.95 THz dielectric-lined structure. Theoretical analysis supports the experimental results. Further exploration and applications of this technique will be discussed as well.
* M. Rosing, J. Simpson, Argonne Wakefield Accelerator Note, WF -144 (1990).

MOPPP021

Longitudinal Beam Dynamics at the ALICE Acclerator R&D Facility

booster, linac, simulation, gun

610

F. Jackson, D. Angal-Kalinin, S.P. Jamison, J.W. McKenzie, T.T. Ng, Y.M. Saveliev, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The ALICE facility is an energy recovery test accelerator whose applications include an IR-FEL and THz generation. Of primary importance to the performance of the main ALICE applications is the understanding and control of the longitudinal dynamics, which are less amenable to measurement than the transverse. The longitudinal dynamics of the beam evolve are studied in simulation and experiment in several areas of the machine. Simulations of the low energy injector where space charge and velocity bunching may occur are presented. Path length measurement using time-of-arrival monitors are carried out.

MOPPP022

ALICE: Status, Developments and Scientific Programme

gun, radiation, acceleration, cryomodule

613

Y.M. Saveliev
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

ALICE (Accelerators and Lasers In Combined Experiments) is a multifunctional ERL based R&D facility that operates in various regimes, both energy recovery and non energy recovery, depending on the project undertaken (beam energy 10-28MeV, bunch charge 20-100pC, train length from a single bunch to 100us). In early 2012, the DC HV photoinjector gun is expected to begin operation at nominal 350kV and a new cryomodule, a result of a wide international collaboration, will be installed and commissioned on ALICE. The improvements in beam dynamics and the overall beam quality will be discussed in this paper. The overview of the ALICE scientific programme including IR-FEL lasing and its application for scanning near field optical microscopy, generation and applications of coherent broadband THz radiation for life sciences and solid state physics, studies of the first non-scaling FFAG EMMA for which ALICE serves as an injector and accelerator physics research will also be presented.

MOPPP028

SRF Photoinjector for Proof-of-principle Experiment of Coherent Electron Cooling at RHIC

electron, SRF, gun, emittance

622

D. Kayran, S.A. Belomestnykh, I. Ben-Zvi, J.C. Brutus, X. Liang, G.T. McIntyre, I. Pinayev, B. Sheehy, J. Skaritka, T. Srinivasan-Rao, R. Than, J.E. Tuozzolo, Q. Wu, T. Xin
BNL, Upton, Long Island, New York, USA
V. Litvinenko, M. Ruiz-Osés
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy and by Stony Brook DOE grant DE-SC0005713.
Coherent Electron Cooling (CEC) based on FEL amplifier promises to be a very good way to cool protons and ions at high energies. A proof of principle experiment to demonstrate cooling at 40 GeV/u is under construction at BNL. One of possible sources to provide sufficient quality electron beam for this experiment is a SRF photoinjector. In this paper we discuss design and simulated performance of the photoinjector based on existing 112 MHz SRF gun and newly designed single-cavity SRF linac operating at 704 MHz.

MOPPP032

Longitudinal Phase Space Studies at the PITZ Facility

electron, laser, radiation, gun

631

M. Mahgoub, J.W. Bähr, H.-J. Grabosch, M. Groß, L. Hakobyan, G. Klemz, G. Kourkafas, M. Krasilnikov, D. Malyutin, A. Oppelt, M. Otevřel, B. Petrosyan, K. Rosbach, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
I.I. Isaev
MEPhI, Moscow, Russia
Ye. Ivanisenko
IERT, Kharkov, Ukraine
M. Khojoyan
ANSL, Yerevan, Armenia
J. Li
USTC/NSRL, Hefei, Anhui, People's Republic of China
B. Marchetti
INFN-Roma II, Roma, Italy
D. Richter
HZB, Berlin, Germany
J. Rönsch-Schulenburg
Uni HH, Hamburg, Germany

Photoinjectors are a cornerstone for short-wavelength Free Electron Lasers (FELs) like FLASH and the European XFEL in Hamburg, Germany. The Photo Injector Test facility at DESY, location Zeuthen (PITZ), was built to develop and optimize such photoinjectors. The PITZ facility is capable of generating long trains of electron bunches, which can be accelerated up to ~25 MeV/c. Studying and optimizing the longitudinal properties of the electron bunch is an important topic at PITZ. A streak system consisting of Silica Aerogel radiators, optical transition radiation (OTR) screens, optical transmission line, and a streak camera is used to study the longitudinal properties with an accuracy of some ps. Due to the high radiation level in the facility, many of the lenses in the optical transmission line have turned brown, reducing the efficiency of the system. Some of the lenses were recovered by baking them up to 180°C. In contrast, few sensitive objective lenses can not be baked, rather they were recovered via exposure to infrared radiation with the proper wave length. An overview of the system, the difficulties, and the modifications needed to overcome the radiation effects are presented.

MOPPP033

Diagnostics at PITZ 2.0 Beamline: Status and New Developments

emittance, electron, diagnostics, dipole

634

M. Otevřel, A. Donat, H.-J. Grabosch, M. Groß, L. Hakobyan, H.M. Henschel, L. Jachmann, M. Khojoyan, G. Klemz, W. Köhler, G. Koss, G. Kourkafas, M. Krasilnikov, K. Kusoljariyakul, H. Leich, J. Li, M. Mahgoub, D. Malyutin, B. Marchetti, J. Meissner, A. Oppelt, M. Penno, B. Petrosyan, M. Pohl, S. Riemann, M. Sachwitz, B. Schöneich, J. Schultze, A. Shapovalov, F. Stephan, F. Tonisch, G. Vashchenko, L.V. Vu, T. Walter, S. Weisse, R.W. Wenndorff, M. Winde
DESY Zeuthen, Zeuthen, Germany
G. Asova
INRNE, Sofia, Bulgaria
N.I. Brusova, L.V. Kravchuk, V.V. Paramonov
RAS/INR, Moscow, Russia
A. Gonnin, M. Joré, B. Mercier, C. Prevost, A. Variola
LAL, Orsay, France
I.I. Isaev
MEPhI, Moscow, Russia
Ye. Ivanisenko
IERT, Kharkov, Ukraine
D. Richter
HZB, Berlin, Germany
S. Rimjaem
Chiang Mai University, Chiang Mai, Thailand
A.A. Zavadtsev, D.A. Zavadtsev
Nano, Moscow, Russia

The main aim of the Photo Injector Test Facility at DESY, Zeuthen (PITZ) site is to develop and test an FEL photo injector system capable of producing high charge short electron bunches of lowest possible transverse emittance to allow optimum FEL performance. The last major beamline upgrade realized in the second half of the year 2011 completed the evolution of the PITZ setup ongoing since 2005. The most recent upgrades include the installation of a new RF deflecting cavity - a prerequisite for longitudinal emittance and high resolution slice emittance measurements and installation of a new dispersive section for longitudinal phase space diagnostics of the high energy electron bunches. The paper will give an overview on electron beam diagnostics at PITZ, including the above mentioned upgrades.

MOPPP040

Resistive Wall Heating of the Undulator in High Repetition Rate FELs

undulator, electron, wakefield, impedance

652

J. Qiang, J.N. Corlett, P. Emma
LBNL, Berkeley, California, USA
J. Wu
SLAC, Menlo Park, California, USA

Funding: Work supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
In next generation high repetition rate FELs, beam energy loss due to resistive wall wakefields will produce significant amount of heat. The heat load for a superconducting undulator (operating at low temperature), must be removed and will be expensive to remove. In this paper, we study this effect in an undulator proposed for a Next Generation Light Source (NGLS) at LBNL. We benchmark our calculations with measurements at the LCLS and carry out detailed parameter studies using beam from a start-to-end simulation. Our preliminary results suggest that the heat load in the undulator is about 2 W/m with an aperture size of 6 mm for nominal NGLS design parameters.

MOPPP071

In Vacuum Conduction Cooled Superconducting Switch for Insertion Devices with Variable Period Length

vacuum, power-supply, insertion, insertion-device

726

T. Holubek, T. Baumbach, S. Casalbuoni, S. Gerstl, A.W. Grau, M. Hagelstein, D. Saez de Jauregui
Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
C. Boffo, W. Walter
BNG, Würzburg, Germany

Switching the period length allows to increase the tunability of an insertion device. This can be realized in superconducting insertion devices (IDs) by reversing the current in a separately powered subsets of the superconducting windings. In order to use only one power supply instead of two for the two circuits, reducing the thermal input to the device, work is ongoing at ANKA to develop a superconducting switch. In this work we present the results of the test of an in-vacuum housed, conduction-cooled superconducting switch.

MOPPP076

Design Considerations for a Hybrid Undulator Applied in a Terahertz FEL Oscillator

undulator, electron, radiation, cavity

738

B. Qin, M. Fan, Y.Q. Xiong
Huazhong University of Science and Technology (HUST), Wuhan, People's Republic of China
Y.J. Pei
USTC/NSRL, Hefei, Anhui, People's Republic of China
P. Tan
HUST, Wuhan, People's Republic of China

A planer undulator using hybrid permanent magnet scheme was designed for a FEL based 1THz~3THz radiation source. The influence of the undulator magnetic field errors, including peak field shift and field integrals errors, on the coherent radiation performance such as the gain per pass is investigated. And finally specifications of the undulator are determined.

MOPPP085

Single Electron Dynamic of Microwave Undulator

electron, undulator, radiation, free-electron-laser

753

C. Chang, J. Neilson, C. Pellegrini, M. Shumail, S.G. Tantawi
SLAC, Menlo Park, California, USA

The analytical and numerical calculations for the dynamic of single electron and beam in RF undulator have been conducted and compared. The transverse and longitudinal velocity, trajectory, energy variation, and the spontaneous radiation are studied. It is found that the forward and backward wave (FW/BW) components have different contribution on electron motion and radiation, most of the energy spread comes from FW component, in other words, the effect of FW on modulating the electron energy is much stronger than that of BW for the same undulating-amplitude value, which mechanism has been analyzed.

MOPPR017

Preliminary Measurement Results of the Upgraded Energy BPM at FLASH

pick-up, LLRF, electron, controls

813

U. Mavrič, M. Felber, C. Gerth, H. Schlarb
DESY, Hamburg, Germany
W. Jałmużna, A. Piotrowski
TUL-DMCS, Łódź, Poland

The energy beam position monitor in the dispersive section of the two bunch compressors is a valuable instrument for regular operation of FLASH. Recently, an upgrade of the existing instrument to a uTCA form factor has been started. The basic principle of the time-of-flight measurement will remain the same, however the detection of the phases and amplitudes of two pulses has been moved to the programmable gate array. Other changes include different RF frequencies of detection, optimization of the front-end section and integration into the control system. A preliminary version of the system has been tested at FLASH and the results are presented in the paper.

MOPPR019

Beam Profile Imaging Based on Backward Transition Radiation in the Extreme Ultraviolet Region

radiation, electron, target, diagnostics

819

L.G. Sukhikh, S. Bajt, G. Kube
DESY, Hamburg, Germany
W. Lauth
IKP, Mainz, Germany
Yu.A. Popov, A. Potylitsyn
Tomsk Polytechnic University, Tomsk, Russia

Backward transition radiation (BTR) in the optical spectral region is widely used for beam profile diagnostics in modern electron linacs. However, the experience from linac based light sources shows that BTR diagnostics might fail because of coherence effects in the emission process. To overcome this problem of coherent emission it was proposed to use BTR in the extreme ultraviolet (EUV) region*, and measurements of the angular EUV BTR distribution were presented in Ref. **. This contribution summarizes the results of a beam profile imaging experiment using EUV BTR. The experiment was carried out using the 855 MeV electron beam of the Mainz Microtron MAMI. EUV BTR was generated at a molybdenum target deposited onto a silicon substrate, and imaging was realized using a spherical multilayer mirror which was optimized for a wavelength of 19 nm. Preliminary results will be presented and compared to ordinary optical BTR imaging together with a discussion of future possibilities of the proposed diagnostic method.
* L.G. Sukhikh et al., Nucl. Instrum. Methods A623, 567 (2010).
** L.G. Sukhikh et al., Proc. of DIPAC-2011, Hamburg (Germany), 544 (2011).

MOPPR032

Electron Beam Diagnostics based on Transverse Feedback System at Duke Storage Ring

storage-ring, feedback, electron, monitoring

849

W. Xu, D.H. He
USTC/NSRL, Hefei, Anhui, People's Republic of China
J.Y. Li, W. Wu, Y.K. Wu
FEL/Duke University, Durham, North Carolina, USA

Funding: This work is supported in part by the US DOE grant no. DE-FG02-97ER41033.
To combat electron beam instabilities, a field programmable gate array (FPGA) based bunch-by-bunch transverse feedback (TFB) has been developed for the Duke storage ring. While it is capable of suppressing transverse beam instabilities for multi-bunch operation, the TFB system has not been needed for typical operation of the Duke storage ring FEL. To explore the great potential of this system, we have focused on the development of TFB based beam diagnostics. A TFB based tune measurement system has been developed using two methods: the tune scan method and tune monitoring method. With the tune monitoring method, a much faster method of the two, we have studied the tune stability of the electron beam in the Duke storage ring. This tune measurement system also allows us to conduct chromaticity measurements more quickly, compared with the existing chromaticity measurement system using a network analyzer. Finally, the TFB based tune system has been used to calibrate the tune knob and chromaticity knob for the Duke storage ring.

MOPPR035

Study of the Signal Processing System for a Cavity Beam Position MonitorS

cavity, electron, factory, simulation

855

B.P. Wang, Y.B. Leng, L.Y. Yu, W.M. Zhou
SINAP, Shanghai, People's Republic of China
Z.C. Chen, R.X. Yuan, N. Zhang
SSRF, Shanghai, People's Republic of China

A cavity beam position monitor (CBPM), which can realize nanometer-level resolution as reported, is important and indispensable for a free electron laser (FEL) facility. A prototype of CBPM, with resonant frequency of 5712 MHz, has been installed in the Shanghai deep ultraviolet free-electron laser source (SDUV-FEL) facility. A plug & play CBPM signal processor based on a broadband oscilloscope embedded IOC and FFT technology has been developed to do quick evaluation of prototype. According to the evaluation results, a series of simulation using Monte Carlo simulation method, has been carried as a guideline for the design of dedicated CBPM signal processing system. The development progress of signal processing system will be introduced as well.

TUXB02

Review of ERL Projects at KEK and Around the World

linac, gun, electron, emittance

1040

N. Nakamura
KEK, Ibaraki, Japan

Future synchrotron light sources based on energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. The Japanese collaboration team is making efforts for realizing an ERL-based VUV and X-ray source with R&D efforts on super-conducting cavities and the electron gun at KEK and elsewhere. This presentation will describe the developments of the compact ERL project and the outline of the 3-GeV ERL light source project at KEK and also review ERL projects around the world, including potential applications to colliders.

Slides TUXB02 [25.328 MB]

TUOBB03

Status of the FERMI@Elettra Project

laser, electron, radiation, photon

1092

M. Svandrlik, E. Allaria, L. Badano, S. Bassanese, F. Bencivenga, E. Busetto, C. Callegari, F. Capotondi, D. Castronovo, M. Coreno, P. Craievich, I. Cudin, G. D'Auria, M. Dal Forno, M.B. Danailov, R. De Monte, G. De Ninno, A.A. Demidovich, M. Di Fraia, S. Di Mitri, B. Diviacco, A. Fabris, R. Fabris, W.M. Fawley, M. Ferianis, E. Ferrari, L. Fröhlich, P. Furlan Radivo, G. Gaio, L. Giannessi, R. Gobessi, C. Grazioli, E. Karantzoulis, M. Kiskinova, M. Lonza, B. Mahieu, C. Masciovecchio, S. Noè, F. Parmigiani, G. Penco, E. Principi, F. Rossi, L. Rumiz, C. Scafuri, S. Spampinati, C. Spezzani, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, M. Zaccaria, D. Zangrando, M. Zangrando
ELETTRA, Basovizza, Italy

Funding: The work was supported in part by the Italian Ministry of University and Research under grants FIRB-RBAP045JF2 and FIRB-RBAP06AWK3.
The FERMI@Elettra seeded Free Electron Laser has provided the first photons to the experimental stations during 2011. The first FEL line in operation is FEL-1, covering the wavelength range between 100 nm and 20 nm. The facility will be opened to users by the end of 2012. In the meantime the installation of the second FEL line, FEL-2 covering the higher energy range down to 4 nm, is progressing on schedule and first tests have started. A description of the status of the project is presented here.

Slides TUOBB03 [5.316 MB]

TUEPPB010

Oscillator Seeding of a High Gain Harmonic Generation FEL in a Radiator-first Configuration

electron, radiation, laser, bunching

1137

P.R. Gandhi, J.S. Wurtele
UCB, Berkeley, California, USA
G. Penn, M.W. Reinsch
LBNL, Berkeley, California, USA

A longitudinally coherent X-ray pulse from a high repetition rate free electron laser (FEL) is desired for a wide variety of experimental applications. However, generating such a pulse with a repetition rate greater than ~1 MHz is a significant challenge. The desired high rep rate sources, primarily high harmonic generation with intense lasers in gases or plasmas, do not exist now, and, for the multi-MHz bunch trains that superconducting accelerators can potentially produce, are likely not feasible with current technology. In this paper, we propose to place an oscillator downstream of a radiator. The oscillator generates radiation that is used as a seed for a high gain harmonic generation (HGHG) FEL which is upstream of the oscillator. For the first few pulses the oscillator builds up power and, until power is built up, the radiator has no HGHG seed. As power in the oscillator saturates, the HGHG is seeded and power is produced. The dynamics and stability of this radiator-first scheme is explored analytically and numerically. A single-pass map is derived using a semi-analytic model for FEL gain and saturation. Iteration of the map is shown to be in good agreement with simulations.

TUEPPB011

Echo Enabled High Mode Generation for X-ray FELs

laser, electron, bunching, free-electron-laser

1140

E. Hemsing
SLAC, Menlo Park, California, USA
A. Marinelli
UCLA, Los Angeles, California, USA

Funding: Work supported by U.S. DOE under Contract Nos. DE-AC02-76SF00515 and DE-FG02-07ER46272.
We describe a simple technique based on a modified echo-enabled harmonic generation (EEHG) scheme to manipulate the three-dimensional electron beam microbunching distribution in order to generate higher-order optical modes in an FEL. As with EEHG, the concept uses two modulators and two chicanes to produce microbunching. However, in one of the modulators, the resonant interaction with the laser has a well-defined transverse structure that becomes strongly correlated to the longitudinal microbunching distribution. Both high-harmonic frequencies and high transverse mode numbers can be generated through a transversely-dependent echo effect.

TUPPC047

New Storage Ring Lattice for the Duke FEL Wiggler Switchyard System

wiggler, lattice, storage-ring, quadrupole

1272

H. Hao, J.Y. Li, Y.K. Wu
FEL/Duke University, Durham, North Carolina, USA

Funding: This work is supported in part by the US DOE grant no. DE-FG02-97ER41033.
The Duke storage ring is a dedicated drive for the OK-4 FEL and OK-5 FEL, and for the state-of-the-art Compton gamma-ray source, High Intensity Gamma-Ray Source (HIGS). To produce FEL lasing below 190 nm and gamma-ray beams above 100 MeV, the FEL system needs to be upgraded by adding two helical OK-5 wigglers to increase the FEL gain with four OK5 wigglers for the VUV operation. To simultaneously preserve the linear polarization capability of the gamma-ray beam produced by the planar OK-4 FEL, a wiggler switchyard system is under development which will enable the switch between two planar OK-4 wigglers and two helical OK-5 wigglers in the middle of the FEL straight. In this work, we present the new magnetic lattice designed for the operation of the wiggler switchyard system. This new lattice is developed with great flexibility for the operation with different numbers of FEL wigglers, variable betatron tunes, and adjustable electron beam sizes at the collision point for the HIGS. In addition, the new lattice is developed for the operation in a wide range of energies, from 280 MeV to 1.2 GeV, with proper nonlinear dynamics compensations in order to realize a large dynamic aperture.

TUPPP005

LUNEX5: A French FEL Test Facility Light Source Proposal

laser, emittance, electron, undulator

1611

A. Loulergue, C. Benabderrahmane, M. Bessière, P. Betinelli-Deck, F. Bouvet, A. Buteau, L. Cassinari, M.-E. Couprie, J. Daillant, J.-C. Denard, P. Eymard, B. Gagey, C. Herbeaux, M. Labat, A. Lestrade, P. Marchand, J.L. Marlats, C. Miron, P. Morin, A. Nadji, F. Polack, J.B. Pruvost, F. Ribeiro, J.P. Ricaud, P. Roy
SOLEIL, Gif-sur-Yvette, France
S. Bielawski, C. Evain, C. Szwaj
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
B. Carré
CEA/DSM/DRECAM/SPAM, Gif-sur-Yvette, France
G. Devanz, M. Luong
CEA/DSM/IRFU, France
L. Farvacque, G. Lebec
ESRF, Grenoble, France
G. Lambert, A. Lifschitz, V. Malka, A. Rousse
LOA, Palaiseau, France
M. Le Parquier
CERLA, Villeneuve d'Ascq, France
J. Lüning
CCPMR, Paris, France
R. Roux
LAL, Orsay, France

LUNEX5 is a new synchrotron FEL source project aiming at delivering short and coherent X-ray pulses to probe ultrafast phenomena at the femto-second scale, to investigate extremely low density samples as well as to image individual nm scale objects. The proposed machine layout is based on a 400 MeV super-conducting Conventional Linear Accelerator (CLA) mainly composed of 2 XFEL type cryo-modules together with a normal-conducting high brightness photo RF gun. This present mature and reliable technology is able to deliver high quality electron bunches up to few kHz suitable for user experiments. Further more, the last decade improvement in synchronization and stability offer a fertile land to explore the different and innovative seeded FEL operations aiming at producing higher coherence and energetic X-rays for the pilot user full benefits. In parallel of the CLA branch, the very promising and highly innovative Laser Wake-Field Accelerator (LWFA) able to produce very short electron bunches in the range of the femto-second and high peak current up to few GeV is foreseen as a FEL bench test using the same undulator lines.

TUPPP045

Creation of FELWI using Large Amplification Regime

electron, undulator, resonance, microtron

1707

K.B. Oganesyan
ANSL, Yerevan, Armenia
A.I. Artemyev, D.N. Klochkov
GPI, Moscow, Russia
Y. Rostovtsev
University of North Texas, Denton, Texas, USA

Funding: ISTC project A-1602
The interaction between noncollinear laser and relativistic electron beams in static magnetic undulator has been studied within the framework of dispersion equations. In the limit of small-signal gain the spatial growth rates are found for the collective (Raman) and single-electron (Thompson) regimes. For a free-electron laser without inversion (FELWI), estimates of the threshold laser power are found. The large-amplification regime should be used to bring an FELWI above the threshold laser power.

TUPPP048

Increasing the Spectral Range of the CLIO Infrared FEL User Facility by Reducing Diffraction Losses

undulator, vacuum, laser, simulation

1709

J.-M. Ortega, G. Perilhous, R. Prazeres
LCP/CLIO, Orsay, Cedex, France
H.B. Abualrob, P. Berteaud, L. Chapuis, M.-E. Couprie, T.K. El Ajjouri, F. Marteau, J. Vétéran
SOLEIL, Gif-sur-Yvette, France
J.P. Berthet, F. Glotin
CLIO/ELISE/LCP, Orsay, France

Funding: CNRS/RTRA
The infrared free-electron laser offers a large tunability since the FEL gain remains high throughout the infrared spectral range, and the reflectivity of metal mirrors remains also close to 1. The main limitation comes from the diffraction of the optical beam due to the finite size of the vacuum chamber of the undulator. At CLIO, we have obtained previously* an FEL tunable from 3 to 150 μm by operating the accelerator between 50 and 14 MeV. However, we found that a phenomenon of “power gaps“ is observed in far-infrared : the laser power falls down to zero at some particular wavelengths, whatever the beam adjustments are. We showed that this effect is related to to the waveguiding effect of the vacuum chamber leading to different losses and power outcoupling at different wavelengths**. To alleviate this effect we have designed a new undulator allowing to use a larger vacuum chamber without reducing the spectral tunability and agility of the FEL. From simulations, a large increase of available power is expected in far-infrared. The new undulator has been installed and its performances and first FEL measurement in far-infrared will be presented
* J.M. Ortega, F. Glotin, R. Prazeres
Infrared Physics and Technology, 49, 133 (2006)
** R. Prazeres, F. Glotin, J.-M. Ortega
Phys. Rev. STAB12, 010701 (2009)

TUPPP050

FEL Performances of the French LUNEX5 Project

laser, electron, bunching, undulator

1712

C. Evain, S. Bielawski
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
C. Benabderrahmane, M.-E. Couprie, C. Evain, M. Labat, A. Loulergue
SOLEIL, Gif-sur-Yvette, France
G. Lambert, A. Lifschitz, V. Malka
LOA, Palaiseau, France

LUNEX5 is a french FEL test facility project based on two types of accelerators: a 400 MeV Conventional Linear Accelerator (CLA) and a Laser WakeField Accelerator (LWFA). The FEL performances will be presented at 20 nm and at 12 nm, wavelengths of interest for the pilot experiments. Results are obtained with GENESIS simulations in time-dependent mode. With the CLA, we compare different seeded schemes as EEHG scheme (Echo Enabled Harmonic Generation) or HGHG scheme (High Gain Harmonic Generation) using HHG source (High Harmonic in Gaz). In parallel, LWFA FEL performances will be presented as a function of the electron bunch characteristics, in particular the bunch length and the energy-spread. The transport of the LWFA output beams into undulators which is found to be a critical issue will be also discussed.

TUPPP052

Status of FLASH

electron, photon, laser, undulator

1715

K. Honkavaara, B. Faatz, J. Feldhaus, S. Schreiber, R. Treusch, M. Vogt
DESY, Hamburg, Germany

FLASH at DESY (Hamburg, Germany) is a free-electron laser user facility driven by a superconducting 1.25 GeV linac based on TESLA technology. During the 3rd user period from September 2010 to September 2011, totally 3740 hours of FEL radiation has been delivered to FEL experiments at more than 30 different wavelengths between 4.7 nm and 45 nm. In addition, beam time has been dedicated to general accelerator physics studies and developments related to the future projects like the European XFEL and the International Linear Collider. After a 3.5 months shutdown in autumn 2011 due to civil construction for a second undulator beamline - FLASH2 - and a following commissioning and study period, 2012 is mainly dedicated to FEL user experiments. This paper summarizes the operation status of the FLASH facility and gives also a short review of the accelerator studies carried out in 2011 and early 2012. The mid-term plans including FLASH2 are presented as well.

TUPPP054

RF Activation and Preliminary Beam Tests of the X-band Linearizer at the FERMI@Elettra FEL Project

klystron, linac, emittance, LLRF

1721

G. D'Auria, S. Di Mitri, G. Penco, C. Serpico
ELETTRA, Basovizza, Italy

FERMI@Elettra is a fourth generation light source facility presently in commissioning at the Elettra Laboratory in Trieste, Italy. It is based on an S-band (3 GHz), 1.5 GeV normal conducting (NC) linac, that provides ultra short e-bunches with high peak current, using two stages of magnetic compression. To linearize the beam longitudinal phase space and to improve the compression process, a forth harmonic RF structure (12 GHz) has been installed downstream the first magnetic chicane. This paper reports the RF activation of the structure and the preliminary tests performed on the beam.

TUPPP056

Study of the Energy Chirp Effects on Seeded FEL Schemes at SDUV-FEL

electron, radiation, laser, undulator

1724

C. Feng, D. Wang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

Seeded free-electron laser (FEL) schemes hold great promise for generation of high brilliant radiation with a narrow bandwidth. Analysis with the idealized electron beam with constant current and energy indicate that both the high-gain harmonic generation (HGHG) and the echo-enabled harmonic generation (EEHG) can produce Fourier-transform limited radiation pulses. However, residual energy variations due to nonlinearity of the accelerator or energy modulations due to microbunching instability will be unavoidable and may broaden the bandwidth of the seeded FEL. In this paper, we study the energy chirp effects on both the HGHG and EEHG schemes. Analytic and simulation calculations are presented and compared with the experimental data. Results show that the coherence properties of the EEHG FEL may not be degraded by the energy chirp when properly choosing the parameters of the dispersion sections.

TUPPP057

Design of a Wavelength Continuously Tunable Ultraviolet Coherent Light Source

laser, radiation, simulation, undulator

1727

T. Zhang, D. Wang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China
X.M. Yang
DICP, Dalian, People's Republic of China

Funding: Work supported by National Natural Science Foundation of China (Grant No. 11075199)
Dalian Coherent Light Source (DCL) is a proposed FEL-based novel light source user facility, will be located in Dalian city, China. DCL will mainly servers on the field of molecular reaction dynamics, ultra-fast physical chemistry experiments, etc. Running on the High-Gain-Harmonic-Generation (HGHG) FEL mode, DCL is expected to cover the FEL wavelength from 50 nm to 150 nm, with the help of continuously tuning Optical Parametric Amplification (OPA) seed laser system, which wavelength can be varied between 240 nm and 360 nm. Numerical simulation shows that the FEL pulse energy of DCL can surpass 100 μJ, at the whole full range wavelength with the undulator tapering technology, and the photon number can be up to 10¹³ per pulse, which is sufficient for user experiments.

TUPPP059

Effects of Metal Mirrors Reflectivity and Aberrations on THz FEL Radiation Performance

cavity, radiation, undulator, electron

1729

P. Tan, T. Yu
HUST, Wuhan, People's Republic of China
M. Fan, Q. Fu, D. Li, B. Qin, Y.Q. Xiong, Y.B. Yibin
Huazhong University of Science and Technology (HUST), Wuhan, People's Republic of China

The primary design study of terahertz free-electron laser (FEL) is presented in this paper. The effects of optical cavity parameter, metal mirrors reflectivity and aberrations on the THz FEL radiation performance have been explored. The reflectivity characteristics of copper, silver and gold are tested in terahertz region. The effects of metal mirrors reflectivity and aberrations on the THz FEL radiation performance are studied by numerical simulation.

TUPPP061

Status of the PAL-XFEL Project

undulator, linac, gun, electron

1735

J.H. Han, H.-S. Kang, I.S. Ko
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: The Ministry of Education, Science and Technology of the Korean Government
PAL-XFEL is designed to generate X-ray radiation in the range of 0.1 and 10 nm for users. The machine consists of a 10 GeV linear accelerator and five undulator beamlines. Electron beams are generated at a low emittance S-band photocathode RF gun and accelerated with an S-band normal conducting linac. Three hard X-ray beamlines will be located at the end of the linac. Electron beams for two soft X-ray beamlines will be switched at a medium energy. The project started in 2011 and the building construction is ongoing. Resent progress of the project and an update of the current progress are presented.

TUPPP062

Start to End Simulation of Three Bunch Compressor Lattice for PAL XFEL

lattice, emittance, linac, simulation

1738

H.-S. Kang, M.-H. Cho, J.H. Han, T.-H. Kang, I.S. Ko
PAL, Pohang, Kyungbuk, Republic of Korea
C.H. Yi
POSTECH, Pohang, Kyungbuk, Republic of Korea

The PAL XFEL is a 0.1-nm hard X-ray FEL project starting from 2011 to finish in 2014, which aims at achieving higher photon flux than 10¹² photons/pulse at 0.1 nm using a 10 GeV electron linac. The PAL XFEL is designed to have a hard x-ray undulator line at the end of linac and a branch line at 2.65 GeV point for soft X-ray undulator line. The three bunch compressor lattice (3-BC) is chosen to minimize emitance growth due to CSR and minimize correlated energy spread. The 3-BC lattice makes it possible to operate soft X-ray FEL undulator line simultaneously and independently from hard X-ray FEL undulator line.

TUPPP064

Microbunching Instability Studies in SwissFEL

simulation, laser, booster, linac

1744

S. Bettoni, B. Beutner
Paul Scherrer Institut, Villigen, Switzerland
V.A. Goryashko
NASU/IRE, Kharkov, Ukraine

Shot noise or an initial intensity modulation in the beam pulse may have a strong effect in the FEL linacs and also severely degrade the machine performances in terms of FEL performances. In this paper we present the simulations done to study this effect in SwissFEL, the future free electron laser under design at Paul Scherrer Institute. In particular we calculated the gain of the microbunching instability in the low and high energy part and we performed start-to-end simulations using as initial distribution something as close as possible to the laser profile measured at the SwissFEL injector test facility. We finally present the preliminary calculations to estimate the effect of the laser heater to mitigate this effect.

TUPPP066

CLARA - A Proposed New FEL Test Facility for the UK

electron, laser, undulator, diagnostics

1750

J.A. Clarke, D. Angal-Kalinin, D.J. Dunning, S.P. Jamison, J.K. Jones, J.W. McKenzie, B.L. Militsyn, N. Thompson, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom
I.P.S. Martin
Diamond, Oxfordshire, United Kingdom

A new single pass national FEL test facility, CLARA, is proposed to be constructed at Daresbury Laboratory in the UK. The aim of CLARA is to develop a normal conducting test accelerator able to generate longitudinally and transversely bright electron bunches and to use these bunches in the experimental production of stable, synchronized, ultra short photon pulses of coherent light from a single pass FEL with techniques directly applicable to the future generation of light source facilities. In addition the facility will be an ideal test bed for demonstrating innovative technologies such as high repetition rate normal conducting RF linacs and advanced undulator designs. This paper will describe the design of CLARA, pointing out the flexible features that will be incorporated to allow multiple novel FEL schemes to be proven.

TUPPP068

Comparison of Compression Schemes for CLARA

emittance, linac, sextupole, cavity

1756

P.H. Williams, J.W. McKenzie
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
J.K. Jones, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom

CLARA (Compact Linear Advanced Research Accelerator) at Daresbury Laboratory is proposed to be the UK’s national FEL test facility. The accelerator will be a ~250 MeV electron linac capable of producing short, high brightness electron bunches. The machine comprises a 2.5 cell RF photocathode gun, one 2 m and three 5 m normal conducting S-band (2998MHz) accelerating structures and a variable magnetic compression chicane. CLARA will be used as a test bed for novel FEL configurations. We present a comparison of acceleration and compression schemes for the candidate machine layout.

TUPPP069

A Compact, Modular Electron Beam Delay Line for Use in Novel Free-Electron Laser Schemes

undulator, quadrupole, electron, lattice

1759

J.K. Jones, J.A. Clarke, N. Thompson
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Two Free-Electron Laser (FEL) schemes have been proposed, for the generation of attosecond pulse trains* and for the improvement of the longitudinal coherence of SASE FELs**, in which repeated electron delays are implemented within the undulator lattice. To obtain the maximum performance and flexibility from these schemes it is advantageous to use an electron delay line that satisfies the isochronicity conditions, as well as being compact, modular and, ideally, variable. In this paper we present initial designs for such a system, along with simulations of its performance. We investigate both in-undulator and out-of-undulator designs, and compare the applicability of each for various aspects of the FEL design, as well as commenting on the mechanical and magnetic implications of the schemes.
* N.R. Thompson and B.W.J. McNeil. Phys. Rev. Lett. 100, 203901 (2008).
** N.R. Thompson, D.J. Dunning and B.W.J. McNeil, IPAC2010, TUPE050, p. 2257 (2010).

TUPPP070

Next Generation Light Source R&D and Design Studies at LBNL

linac, electron, laser, gun

1762

J.N. Corlett, B. Austin, K.M. Baptiste, D.L. Bowring, J.M. Byrd, S. De Santis, P. Denes, R.J. Donahue, L.R. Doolittle, P. Emma, D. Filippetto, G. Huang, T. Koettig, S. Kwiatkowski, D. Li, T.P. Lou, H. Nishimura, H.A. Padmore, C. F. Papadopoulos, G.C. Pappas, G. Penn, M. Placidi, S. Prestemon, D. Prosnitz, J. Qiang, A. Ratti, M.W. Reinsch, D. Robin, F. Sannibale, D. Schlueter, R.W. Schoenlein, J.W. Staples, C. Steier, C. Sun, T. Vecchione, M. Venturini, W. Wan, R.P. Wells, R.B. Wilcox, J.S. Wurtele
LBNL, Berkeley, California, USA

Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
LBNL is developing design concepts for a multi-beamline soft x-ray FEL array powered by a superconducting linear accelerator, operating with a high bunch repetition rate of approximately one MHz. The cw superconducting linear accelerator is supplied by an injector based on a high-brightness, high-repetition-rate photocathode electron gun. Electron bunches are distributed from the linac to the array of independently configurable FEL beamlines with nominal bunch rates up to 100 kHz in each FEL, and with even pulse spacing. Individual FELs may be configured for different modes of operation, and each may produce high peak and average brightness x-rays with a flexible pulse format, and with pulse durations ranging from sub-femtoseconds to hundreds of femtoseconds. In this paper we describe conceptual design studies and optimizations. We describe recent developments in the design and performance parameters, and progress in R&D activities.

TUPPP071

Design Concepts of a Beam Spreader for a Next Generation Free Electron Laser

electron, kicker, septum, linac

1765

M. Placidi, P. Emma, J.-Y. Jung, G.C. Pappas, D. Robin, C. Sun, W. Wan
LBNL, Berkeley, California, USA

LBNL is developing design concepts for a multi-beamline soft x-ray FEL array powered by a superconducting linear accelerator, operating with a high bunch repetition rate of approximately one MHz. Electron bunches are distributed from the linac to the array (up to 10) independently configurable FEL beamlines with nominal bunch rates up to 100 kHz in each FEL, and with even pulse spacing. This distribution to the different FELs is made by the beam spreader for which the design has to relative compact while not significantly perturbing the quality of the electron beam and subsequent performance of the FELs. We report on our conceptual design for the spreader. The spreader lattice has two distinct parts, namely the beam take-off section and the FEL fan-out distributions section. Each section is achromatic and isochronous. The effect of coherent synchrotron radiation and micro-bunching has been studied when passing through the spreader and simulations show no significant deterioration in the beam quality.

TUPPP073

Machine Parameter Studies for an FEL Facility Using STAFF

photon, undulator, linac, emittance

1768

M.W. Reinsch, B. Austin, J.N. Corlett, L.R. Doolittle, P. Emma, G. Penn, D. Prosnitz, J. Qiang, A. Sessler, M. Venturini
LBNL, Berkeley, California, USA
J.S. Wurtele
UCB, Berkeley, California, USA

Designing an FEL facility requires balancing multiple science needs, FEL and accelerator physics constraints, and engineering limitations. STAFF (System Trade Analysis for an FEL Facility) is a MATLAB program that enables the user to rapidly explore a large range of Linac and FEL design options to meet science requirements. The code uses analytical models such as the Ming Xie formulas when appropriate and look-up tables when necessary to maintain speed and flexibility. STAFF's modular design simplifies the inclusion of new physics models for FEL harmonics, wake fields, cavity higher-order modes and aspects of linac design such as the optimization of a laser heater, harmonic linearizer, and one or more bunch compressors. Code for the microbunching instability has been included as well. STAFF also supports multiple undulator technologies. STAFF permits the user to study error tolerances and multiple beamlines so as to explore the full capabilities of an entire user facility. This makes it possible to optimize the integrated system in terms of performance metrics such as photons/pulse, photons/sec and tunability range.

TUPPP074

Beam Dynamics Studies of a High-repetition Rate Linac Driver for a 4th-generation Light Source

emittance, simulation, linac, laser

1771

M. Venturini, J.N. Corlett, P. Emma, C. F. Papadopoulos, G. Penn, M. Placidi, J. Qiang, M.W. Reinsch, F. Sannibale, C. Steier, R.P. Wells
LBNL, Berkeley, California, USA

We present progress toward the design of a super-conducting linac driver of a high repetition rate FEL-based soft x-ray light source. The machine is intended to accept beams generated by the APEX* photocathode gun, operating in the MHz range, and deliver them to an array of SASE and seeded FEL beamlines. After reviewing the beam-dynamics considerations that are informing specific lattice choices we discuss the expected performance of the proposed machine design and its ability to meet the desired FEL specifications. We consider the merit of possible alternate designs (e.g., a one-stage compressor vs. a two-stage compressor) and the trade-offs between competing demands on the beam attributes (e.g., high peak current vs. acceptable energy spread).
* F. Sannibale et al., this conference.

TUPPP076

Soft Orbit Bumps for Duke Storage Ring VUV FEL Operation

radiation, wiggler, electron, dipole

1774

S.F. Mikhailov, J.Y. Li, V. Popov, P.W. Wallace, Y.K. Wu
FEL/Duke University, Durham, North Carolina, USA

Funding: This work is supported in part by the US DoE grant # DE-FG02-97ER41033.
The Duke FEL and High Intensity Gamma-ray Source (HIGS) facility is operated with an electron beam from 0.24 to 1.2 GeV and a photon beam from 190 to 1060 nm. The current range of the gamma-beam energy is from 1 MeV to about 100 MeV, with the maximum total gamma-flux of more then 10¹⁰ gammas per second around 10 MeV. Production of the high intensity, high energy gamma-beams of 60-100 MeV using UV-VUV mirrors of 240 - 190 nm requires and high energy, high current electron beams of 0.9-1.05 GeV. The radiation damage problem becomes more severe for VUV FEL operation below 190 nm. The radiation from the End-of-Arc (EOA) bending magnets, instead of the radiation from FEL wigglers, is the dominant cause of a rapid degradation of the downstream FEL mirror. In this work, we propose a number of measures to significantly reduce the radiation from these dipole magnets as well as other potential sources of synchrotron radiation toward the FEL mirror. In particular, we describe the development of an orbit bump using designated "soft" orbit correctors. The magnetic field of these correctors is limited to produce a radiation with a critical wavelength close or below the FEL wavelength.

TUPPP079

Design Alternatives for a Free Electron Laser Facility

linac, undulator, electron, photon

1777

K. Jacobs, J. Bisognano, R.A. Bosch, D. Eisert, M.V. Fisher, M.A. Green, R.G. Keil, K.J. Kleman, J.G. Kulpin, G.C. Rogers, R. Wehlitz
UW-Madison/SRC, Madison, Wisconsin, USA
T. Chiang, T.J. Miller
University of Illinois, Urbana, USA
J.E. Lawler, D. Yavuz
UW-Madison/PD, Madison, Wisconsin, USA
R.A. Legg
JLAB, Newport News, Virginia, USA
R.C. York
FRIB, East Lansing, Michigan, USA

The University of Wisconsin-Madison is continuing design efforts for a vacuum ultraviolet/X-ray Free Electron Laser facility. The design incorporates seeding the FEL to provide fully coherent photon output at energies up to ~1 keV. The focus of the present work is to minimize the cost of the facility while preserving its performance. To achieve this we are exploring variations in the electron beam driver for the FEL, in undulator design, and in the seeding mechanism. Design optimizations and trade-offs between the various technologies and how they affect the FEL scientific program will be presented.

TUPPP082

Optimization of a Terawatt Free Electron Laser

undulator, electron, radiation, focusing

1780

J. Wu, X. Huang, Y. Jiao, A.U. Mandlekar, T.O. Raubenheimer, S. Spampinati, G. Yu
SLAC, Menlo Park, California, USA
P. Chu
FRIB, East Lansing, Michigan, USA
J. Qiang
LBNL, Berkeley, California, USA

Funding: Work supported by U.S. Department of Energy, Office of Basic Energy Sciences, under Contract DE-AC02-76SF00515.
There is great interest in generating a terawatt (TW) hard X-ray free electron laser (FEL) that will enable coherent diffraction imaging of complex molecules like proteins and probe fundamental high-field physics. A feasibility study of producing such pulses was carried out em- ploying a configuration beginning with an SASE amplifier, followed by a "self-seeding" crystal monochromator, and finishing with a long tapered undulator. The undulator tapering profile, the phase advance in the undulator break sections, the quadrupole focusing strength, etc. are parameters to be optimized. A genetic algorithm (GA) is adopted for this multi-dimensional optimization. Concrete examples are given for LCLS/LCLS-II systems.

TUPPP083

Multi-Dimensional Optimization of a Tapered Free Electron Laser

undulator, radiation, electron, focusing

1783

Y. Jiao, J. Wu
SLAC, Menlo Park, California, USA
Q. Qin
IHEP, Beijing, People's Republic of China

Energy extraction efficiency of a free electron laser (FEL) can be increased when the undulator is tapered. In this paper, we report a multi-dimensional optimizer to maximize the radiation power in a tapered FEL by searching for an optimal taper profile as well as a reasonable variation in electron beam radius. Applications of the proposed multi-dimensional optimization to the terawatt-level, tapered FELs with LCLS-like electron beam parameters are presented, and the proposed optimization scheme is compared with the GINGER’s self-design taper algorithm. At the end, the dependence of the available maximum radiation power on various parameters of the initial electron beam, the initial radiation field and the undulator system is summarized.

TUPPP084

Efficiency Enhancement in a Tapered Free Electron Laser by Varying the Electron Beam Radius

electron, radiation, undulator, simulation

1786

Y. Jiao, J. Wu
SLAC, Menlo Park, California, USA
Q. Qin
IHEP, Beijing, People's Republic of China

Energy extraction efficiency of a free electron laser (FEL) can be increased when the undulator is tapered. An in-depth understanding of the tapering-related physics is required to explore the full potential of a tapered FEL, not only by tapering the undulator parameters in longitudinal dimension, but also optimizing the transverse effects. Based on the modified 1D FEL model and time-steady numerical simulations, we study the contribution of the variation in electron beam radius and the related transverse effects. Taking a terawatt-level, 120-m tapered FEL as example, we demonstrate that a reasonably varied, instead of a constant, electron beam radius along the undulator helps to improve the optical guiding and thus the radiation output.

TUPPP086

A Synchronized FIR/VUV Light Source at Jefferson Lab

laser, wiggler, electron, coupling

1789

S.V. Benson, D. Douglas, G. Neil, M.D. Shinn, G.P. Williams
JLAB, Newport News, Virginia, USA

Funding: This work was supported by U.S. DOE Contract No. DE-AC05-84-ER40150, the Air Force Office of Scientific Research, DOE Basic Energy Sciences.
We describe a dual FEL configuration on the UV Demo FEL at Jefferson Lab that would allow simultaneous lasing at THz and UV wavelengths. The THz source would be an FEL oscillator with a short wiggler providing diffraction-limited pulses with pulse energy exceeding 50 microJoules. The THz source would use the exhaust beam from a UVFEL. The coherent harmonics in the VUV from the UVFEL are outcoupled through a hole. The THz source uses a shorter resonator with either hole or edge coupling to provide very high power THz pulses. Simulations indicate excellent spectral brightness in the THz region with over 100 W/cm^-1 output.

TUPPP087

Commissioning of the Fritz Haber Institute Mid-IR FEL

wiggler, electron, linac, undulator

1792

A.M.M. Todd, H. Bluem, D. Dowell, R. Lange, J.H. Park, J. Rathke, L.M. Young
AES, Princeton, New Jersey, USA
W. Erlebach, S. Gewinner, H. Junkes, A. Liedke, G. Meijer, W. Schöllkopf, W.Q. Zhang, G. von Helden
FHI, Berlin, Germany
S.C. Gottschalk
STI, Washington, USA
K. Jordan
Kevin Jordan PE, Newport News, Virginia, USA
U. Lehnert, P. Michel, W. Seidel
HZDR, Dresden, Germany
R. Wünsch
FZD, Dresden, Germany

The IR and THz FEL at the Fritz Haber Institute (FHI) in Berlin is designed to deliver radiation from 4 to 400 microns. A single-plane-focusing undulator combined with a 5.4-m-long cavity is used is the mid-IR (< 50 micron), while a two-plane-focusing undulator in combination with a 7.2-m-long cavity with a 1-D waveguide for the optical mode is planned for the far-IR. Beam was delivered to the IR beam dump in November 2011. We describe progress since that time in completing the commissioning of the mid-IR beamline and the status of the far-IR beamline design and fabrication.

TUPPP088

Bunch Compressor Design for Potential FEL Operation at eRHIC

emittance, electron, simulation, linac

1795

Y.C. Jing, Y. Hao, V. Litvinenko
BNL, Upton, Long Island, New York, USA

Electron-Relativistic Heavy Ion Collider (eRHIC) is an upgrade project for the current operation of RHIC. It will provide a high quality electron beam with energy recovery scheme to collide with ion beams. One may think of taking advantage of using this electron beam for FEL operation. Bunch compressor is a crucial component to compress the beam to high peak current for undulators and CSR effect needs to be taken care of to preserve the beam quality. In this paper, authors present a novel bunch compressor design with CSR suppression scheme for the potential FEL operation at eRHIC.

TUPPP093

General Results on the Nature of FEL Amplification

electron, laser, free-electron-laser, wiggler

1804

S.D. Webb
Tech-X, Boulder, Colorado, USA
V. Litvinenko, G. Wang
BNL, Upton, Long Island, New York, USA

Free-electron lasers are increasingly important tools for the material and biological sciences, and although numerical and analytical theory is extensive, a fundamental question about the nature of the FEL growing modes has remained unanswered. In this proceeding, we present results of a topological nature concerning the number of amplifying solutions to the 1-dimensional FEL equations as related to the energy distribution of the electron bunches.

WEXB01

Recent Advances and New Techniques in Visualization of Ultra-short Relativistic Electron Bunches

radiation, electron, laser, RF-structure

2091

D. Xiang
SLAC, Menlo Park, California, USA

Funding: Work supported by U.S. DOE under Contract No. DE-AC02-76SF00515.
This talk will address advances in the measurement of ultra-short relativistic bunches at femtosecond frontier in high-energy x-ray free-electron lasers (FELs). In general, this presentation will discuss several recently proposed novel techniques (i.e. mapping z exactly to delta * and x **, optical oscilloscope ***, etc.) that are capable of breaking the femtosecond time barrier in measurements of ultrashort bunches. In particular, this presentation will report on the all-optical, time-resolved method to probe beam longitudinal phase space with femtosecond time scale and 10^-5 energy scale resolution ****. The simultaneous measurement of temporal profile and beam slice energy spread after the FEL interaction is also shown to reveal the time-dependent x-ray radiation profile *****.
* Z. Huang et al., PRSTAB 13, 092801.
** D. Xiang, Y. Ding, PRSTAB 13, 094001.
*** G. Andonian et al., PRSTAB 14, 072802.
**** D. Xiang et al., PRSTAB 14, 112801.
***** Y. Ding et al., FEL11.

Slides WEXB01 [6.873 MB]

WEYB01

The SPring-8 Angstrom Compact Free Electron Laser (SACLA)

laser, electron, emittance, undulator

2106

H. Tanaka
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan

Commissioning of the world's first compact X-ray FEL facility named SPring-8 Angstrom Compact free electron LAser (SACLA) began in the Spring of 2011 and soon demonstrated lasing at a wavelength of 0.12nm. In the autumn of 2011 laser intensity reached sub mJ/pulse in the wavelengths ranging from 0.1 to 0.3 nm. The laser power saturation was also achieved at around or longer than 0.1 nm. The official user operation will start from March 2012. This presentation will cover innovative design aspects of the SACLA construction project, events leading to key milestones in the commissioning process, a review of the present status and perspectives on future upgrades.

Slides WEYB01 [13.170 MB]

WEYB03

High Average Power UV Free Electron Laser Experiments at JLAB

wiggler, cavity, linac, electron

2111

D. Douglas, S.V. Benson, P. Evtushenko, J.G. Gubeli, C. Hernandez-Garcia, R.A. Legg, G. Neil, T. Powers, M.D. Shinn, C. Tennant, G.P. Williams
JLAB, Newport News, Virginia, USA

Funding: Authored by JSA LLC under US DOE Contract #DE-AC05-06OR23177. The U.S. Gov. retains non-exclusive, paid-up, irrevocable, world-wide license to publish/reproduce this manuscript for U.S. Gov. purposes.
Having produced 14 kW of average power at ~2 microns, JLAB has shifted its focus to the ultraviolet portion of the spectrum. This presentation will describe the JLab UV Demo FEL, present specifics of its driver ERL, and discuss the latest experimental results from FEL experiments and machine operations.

Slides WEYB03 [2.863 MB]

WEOBB01

Measurement of the Local Energy Spread of Electron Beam at SDUV-FEL

laser, electron, bunching, radiation

2143

C. Feng, J.H. Chen, H.X. Deng, T. Lan, B. Liu, D. Wang, X. Wang, M. Zhang, T. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

The slice energy spread of electron beam is a very important parameter for high gain free electron lasers (FELs) especially the seeded FELs. Because of its extremely small value, highly accurate measurement of the slice energy spread is rather challenging. In this paper, we propose a novel method to accurately measure the slice energy spread based on the coherent harmonic generation (CHG) scheme. This method has been demonstrated on the Shanghai deep ultraviolent FEL (SDUV-FEL), and the results show that the slice energy spread is about only 1.2keV at the exit of the 136MeV linac when the bunch compressor is off, and this value change to about 2.6keV when the bunch compressor is on.
* Chao Feng, et al, Phys. Rev. ST Accel. Beams 14, 090701 (2011)

Slides WEOBB01 [3.309 MB]

WEIC04

Functional Materials Development using Accelerator-based Light Sources: Current Capabilities and Future Prospects

controls, synchrotron, electron, radiation

2156

W.R. Flavell
UMAN, Manchester, United Kingdom

Funding: UK Engineering and Physical Sciences Research Council (EPSRC), UK Science and Technology Facilities Council (STFC)
The development of accelerator-based light sources has allowed access to photons of very high brightness and wide tunability. These properties of synchrotron radiation (SR) mean that it can be used to resolve questions that can be answered in no other way, enabling unique contributions to the development of functional materials. Increasingly, these benefits have become essential to material evaluation in manufacturing – ranging from intelligent catalysts for automotive emissions control* to next generation photovoltaics**. Bright, tunable X-rays have been a boon to nanotechnology*** in particular, with its requirement for atom-by-atom understanding – and this benefit is enhanced by the microfabrication capabilities of X-ray lithography in LIGA-based techniques. The result is unique potential for nanoscale device manufacture. The application of bright tunable X-rays to the development of nanostructures for a range of industrial applications is illustrated, and the prospects for exploitation of the ultra-high brightness and femtosecond time structure of FEL radiation are discussed.
* H Tanaka et al., Ang. Chemie Int. Ed. 45, 5998 (2006)
** S J O Hardman et al., Phys Chem Chem Phys 13, 20275 (2011)
*** S Biswas et al., Small (2012) DOI: 10.10⁰²/smll201102100

Slides WEIC04 [11.723 MB]

WEPPD049

Characterization of the Engineered Photodiode-based Fiber Link Stabilization Scheme for Optical Synchronization Systems

laser, LLRF, optics, controls

2627

T. Lamb, M.K. Bock, M. Felber, F. Ludwig, H. Schlarb, S. Schulz
DESY, Hamburg, Germany
S. Jabłoński
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland

Pulsed optical synchronization systems are used in modern FELs like FLASH and will be used in the upcoming European XFEL. Their purpose is to distribute synchronization signals with femtosecond stability throughout the machine. Optical fibers are used to transport the pulses carrying the timing information to their end-stations. These fibers have to be continuously delay stabilized in order to achieve the desired precision. In this paper, a photodiode-based detector to measure the drifts of the fiber delay and allows their active correction is presented. Promising results from a first prototype setup of a photodiode-stabilized optical fiber link were the starting point for an engineering of this concept. An enclosure with free-space optics, fiber optics and integrated electronics for the detector, operating at 9.75 GHz, was designed. This unit includes all required parts to stabilize four fiber links. It allows to investigate the temperature sensitivity of the detector. Furthermore, results from drift measurements carried out with a two channel engineered detector are presented in this paper.

WEPPD076

A Fast Kicker for a Staged Dielectric Two-beam Wakefield Accelerator

kicker, wakefield, cavity, klystron

2702

J.G. Power, M.E. Conde, W. Gai
ANL, Argonne, USA
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA

Funding: Work supported by DoE, Office of HEP.
An experimental program to demonstrate staging in a dielectric two-beam wakefield accelerator (dielectric TBA) is being planned at the Argonne Wakefield Accelerator (AWA) facility. We are planning an experiment that both fits in the AWA tunnel and mimics conditions similar to the recently presented conceptual design of a linear collider based on the dielectric TBA. This conceptual design is based on a new parameter space of the TBA scheme utilizing an ultra-short (~20ns) rf pulse in a dielectric TBA. The decelerating structures are driven by a series of drive microbunch trains that are 20 ns in duration and separated by 100 ns. This means that the fast kicker must have an extremely quick risetime as well as become stable within about 50 ns. In this paper, we consider designs for a fast kicker based on RF deflecting cavities and stripline kickers.

WEPPP040

Progress Report on Development of Novel Ultrafast Mid-IR Laser System

laser, acceleration, wakefield, background

2810

R. Tikhoplav, A.Y. Murokh
RadiaBeam, Santa Monica, USA
I. Jovanovic
Penn State University, University Park, Pennsylvania, USA

Finding alternate acceleration mechanisms that can provide very high gradients is of particular interest to the accelerator community. Those mechanisms are often based on either dielectric laser acceleration or laser wakefield acceleration techniques, which would greatly benefit from mid-IR ultrafast high peak power laser systems. The approach of this proposed work is to design a novel ultrafast mid-IR laser system based on optical parametric chirped-pulse amplification (OPCPA). OPCPA is a technique ideally suited for production of ultrashort laser pulses at the center wavelength of 2μm-5μm. Some of the key features of OPCPA are the wavelength agility, broad spectral bandwidth and negligible thermal load. This paper reports on the progress of the development of the ultrafast mid-IR laser system.

WEPPP073

Dynamic Feedback Model for High Repetition Rate Linac-driven FELs

linac, feedback, cavity, beam-loading

2879

J.M. Byrd, L.R. Doolittle, P. Emma, G. Huang, A. Ratti, C. Serrano
LBNL, Berkeley, California, USA

Funding: Work supported by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
One of the concepts for the next generation of linac-driven FELs is a cw superconducting linac driving an electron beam with MHz repetition rates. One of the challenges for next generation FELs is improve the shot-to-shot stability of the energy, charge, peak current, and timing jitter of the electron beam. The use of a cw RF system with MHz beam repetition rates presents an opportunity to use broadband feedback to stabilize the beam parameters. To understand the performance of such a feedback system, we are are developing a dynamic feedback model of the machine with a focus on the longitudinal beam properties. The model is being developed as an extension of the LITrack code and will include the dynamics of the beam-cavity interaction, RF feedback, beam-based feedback, and multibunch effects. In this paper, we will present the status of this model along with results.

WEPPR064

Very Short Range Wake in Strongly Tapered Disk Loaded Waveguide Structures

simulation, wakefield, linac, impedance

3072

A. Grudiev
CERN, Geneva, Switzerland

Electron bunches are very short, both in linear collider and in X-FEL projects. Furthermore, typical disk-loaded waveguide structures used for particle acceleration are tapered. For example in CLIC, in order to achieve high accelerating gradient, the structure is only 26 cells long, which results in strong tapering. In this paper, very short range wake is investigated in the regime where the number of cells needed to arrive at steady state is much larger than the number of cells in a single tapered structure. In this case the very short range wake is dominated by the wake from the smallest aperture. The results of an analytical model and numeric solutions are compared.

THYB02

Influence of Electron Beam Parameters on Coherent Electron Cooling

electron, ion, acceleration, radiation

3213

G. Wang, Y. Hao
BNL, Upton, Long Island, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA
S.D. Webb
Tech-X, Boulder, Colorado, USA

Coherent electron cooling (CeC) is promising to revolutionize the cooling of high energy hadron beams. The intricate dynamics of the CeC depends both on the local density and energy distribution of the beam. This talk should present a rigorous analytical model of the 3D processes (including diffraction) in the modulator and the FEL and describe how the theory is applied to electron beams with inhomogeneous longitudinal density- and energy distributions in the process of CeC. The SPC would like you to describe the influence of electron beam energy and current variations along the bunch length.

Slides THYB02 [0.878 MB]

THPPC054

Installation and Tests of the X-Band Power Plant for the FERMI@Elettra Project

klystron, vacuum, LLRF, power-supply

3410

G. D'Auria, P. Delgiusto, F. Gelmetti, M.M. Milloch, A. Milocco, F. Pribaz, C. Serpico, N. Sodomaco, M. Svandrlik, R. Umer, L. Veljak
ELETTRA, Basovizza, Italy

FERMI@Elettra, the fourth generation light source facility at the Elettra Laboratory in Trieste, Italy, foresees an X-band accelerating section downstream the first bunch compressor to linearize the beam longitudinal phase space. The RF power for the structure is produced by the SLAC XL5 klystron, a scaled version of the XL4 tube, operating at the European frequency of 11.992 GHz. The 50 Hz klystron modulator is based on a standard pulse forming network (PFN) design, with thyratron and pulse transformer, for which there is already an extensive experience at the Elettra laboratory. We report about the installation and tests of the first high power RF station.

THPPC058

S-band Low-level RF System for 10 GeV PAL-XFEL

LLRF, klystron, controls, linac

3422

W.H. Hwang, J.Y. Huang, H.-S. Kang, H.-S. Lee, W.W. Lee
PAL, Pohang, Kyungbuk, Republic of Korea

In PAL, We are constructing a 10GeV PxFEL project. The output power of the klystron is 80 MW at the pulse width of 4 ㎲ and the repetition rate of 120 Hz. And the specifications of the rf phase and amplitude stability are 0.05 degrees(rms) and 0.01%(rms) respectively. We achieved the stability of 0.03 degrees(p-p) at low power rf output using a phase amplitude detection system(PAD) and phase amplitude control(PAC) system. This paper describes the microwave system and the PAD and PAC system for the PxFEL.

THPPD008

Status of the PAL-XFEL Undulator System

undulator, controls, status, dipole

3509

D.E. Kim, H.S. Han, Y.-G. Jung, H.-G. Lee, W.W. Lee, K.-H. Park, H.S. Suh
PAL, Pohang, Kyungbuk, Republic of Korea
J. Pflüger
European XFEL GmbH, Hamburg, Germany

Funding: Work supported by POSCO and MEST of Korea.
Pohang Accelerator Laboratory (PAL) is developing 10 GeV, 0.1 nm SASE based FEL for high power, short pulse X-ray coherent photon sources named PAL-XFEL. At the first stage PAL-XFEL needs two undulator lines for photon source. PAL is developing undulator magnetic structure based on EU-XFEL design. The hard Xray undulator features 7.2 mm min magnetic gap, and 5.0 m magnetic length with maximum effective magnetic field larger than 0.908 T to achieve 0.1nm radiation at 10 GeV electron energy. In this report, we discuss the status of the hard X-ray undulator and soft X-ray undulator designs.

THPPD044

Fabrication and Testing of Curved Test Coil for FRIB Fragment Separator Dipole

dipole, radiation, quadrupole, proton

3611

S.A. Kahn
Muons, Inc, Batavia, USA
J. Escallier, R.C. Gupta, G. Jochen, Y. Shiroyanagi
BNL, Upton, Long Island, New York, USA

Funding: Supported in part by SBIR Grant 4746 · 11SC06273
A critical element of the fragment separator region of the Facility for Rare Isotope Beams (FRIB) is the 30° dipole bend magnet. Because this magnet will be subjected to extremely high radiation and heat loads, operation at 4.5 K would not be possible. High temperature superconductors which have been shown to be radiation resistant and can operated in the 30-50 K temperature range which is more effective for heat removal. An efficient design for this magnet would make use of coils that follow the curvature of the magnet. Winding curved coils with negative curvature are difficult as the coil tends to unwind during the process. As part of an R&D effort for this magnet we are winding a ¼ scale test coil for this magnet with YBCO conductor and are testing it at 77 K. This paper will discuss the winding process and the test results of this study.

THPPP020

Project X with Superconducting Rapid Cycling Synchrotron

synchrotron, extraction, proton, beam-losses

3773

H. Piekarz
Fermilab, Batavia, USA

A synchrotron-based upgrade of Fermilab accelerator complex for high intensity physics with Project X is described. It consists of: 1 GeV pulse linac, 1-8 GeV superconducting rapid cycling synchrotron (SRCS), dual 8 GeV storage ring (SR1,2), and 60 GeV Main Injector(MI). Pulse linac and SRCS operate at 10 Hz while SR1, SR2, and MI operate at 1.33 Hz. SR1 stores 3 and SR2 4 SRCS pulses making physics cycle 0.7 s. SR1 batch is extracted in 0.5 s at 3 locations of its ring providing beams to kaon and 2 muon experiments. SR2 batch is transferred to MI, accelerated to 60 GeV, and extracted to 3 neutrino production targets for Minos, Nova, and LBNE experiments. Main synchrotron parameters are listed and magnet systems described. Projected beam power is compared to expectations with linac-only based upgrade as well as with current and planned similar accelerator facilities elsewhere.

THPPR044

A New Electron Beam Test Facility (EBTF) at Daresbury Laboratory for Industrial Accelerator System Development

electron, gun, laser, vacuum

4074

P.A. McIntosh, D. Angal-Kalinin, S.R. Buckley, J.A. Clarke, A.R. Goulden, C. Hill, S.P. Jamison, J.K. Jones, A. Kalinin, J.W. McKenzie, K.J. Middleman, B.L. Militsyn, T.T. Ng, B.J.A. Shepherd, R.J. Smith, S.L. Smith, N. Thompson, A.E. Wheelhouse
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
N. Bliss, G.P. Diakun, A. Gleeson, T.J. Jones, B.G. Martlew, A.J. Moss, L. Nicholson, M.D. Roper, C.J. White
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

Recent UK government funding has facilitated the implementation of a unique accelerator test facility which can provide enabling infrastructures targeted for the development and testing of novel and compact accelerator technologies, specifically through partnership with industry and aimed at addressing applications for medicine, health, security, energy and industrial processing. The infrastructure provision on the Daresbury Science and Innovation Campus (DSIC) will permit research into areas of accelerator technologies which have the potential to revolutionise the cost, compactness and efficiency of such systems. The main element of the infrastructure will be a high performance and flexible electron beam injector facility, feeding customised state-of-the-art testing enclosures and associated support infrastructure. The facility operating parameters and implementation status will be described, along with primary areas of commercialised technology development opportunities.

FRYAP01

The Future of X-ray FELs

undulator, electron, laser, linac

4180

H.-H. Braun
Paul Scherrer Institut, Villigen, Switzerland

Recent years have brought enormous progress with X-ray FELs. With LCLS and SACLA two facilities with quite different technological approaches have shown the feasibility of SASE FELs in the hard X-ray regime while the SASE FEL FLASH and the recently commissioned laser seeded FEL FERMI@ELETTRA provide coherent light beams of unprecedented brightness at EUV and soft X-ray wavelength. First user experiments at these facilities demonstrate the vast scientific potential of this new type of instrument and have accelerated and triggered R&D and planning for other facilities of its kind worldwide. Projects under construction or in advanced stage of planning are European XFEL, LCLS II, SwissFEL, PAL XFEL, Shanghai XFEL and NGLS. Worldwide R&D efforts for XFELs try to improve performance and reduce size and cost. Focuses are on injector, linac and undulator technologies as well as on FEL seeding methods.

Slides FRYAP01 [24.324 MB]