IPAC2012 - List of Keywords (undulator)

Paper	Title	Other Keywords	Page
MOEPPB013	Simulation and Measurement of Beam Loss in the Narrow-Gap Undulator Straight Section of the Advanced Photon Source Storage Ring	simulation, vacuum, radiation, neutron	106
	J.C. Dooling, M. Borland ANL, Argonne, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02-06CH11357. Simulations indicate the removal of a scraper/collimator in the Sector 37 straight section (SS) of the Advanced Photon Source storage ring (SR) results in increased beam loss in the remaining narrow-gap, insertion device SS, ID4. Modeling with elegant provides loss distributions in the 5-mm aperture vacuum chamber of ID4 and includes the effects of rf system muting and quantum excitation in the bunch. The loss distributions are then used as input to a MARS model of the SS that includes undulator geometry. ID4 has been instrumented with additional monitoring to capture beam loss events, particularly beam dumps. Cerenkov detectors and fiber-optic cable bundles are used to capture temporal profiles of beam loss events. Beam dumps deliver 2600 J to the vacuum chamber and surrounding hardware including undulators. Data indicate a variety of temporal profiles occur during the beam dumps, with the shortest lasting 6 microseconds, FWHM (<2 turns). Such high power and power densities can lead to physical damage of vacuum components if not handled correctly. Touschek scattering loss is also a concern for undulator demagnetization. Comparison of modeling and measurements will be presented.

MOPPD038	Simulation Study of Electron Response Amplification in Coherent Electron Cooling	electron, ion, bunching, FEL	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.

MOPPP016	Feasibility Study of an ERL-based GeV-scale Multi-turn Light Source	linac, brilliance, cryomodule, optics	604
	Y. Petenev, T. Atkinson, A.V. Bondarenko, A.N. Matveenko HZB, Berlin, Germany
	A new generation of particle accelerators based on an Energy Recovery Linac (ERL) is a promising tool for a number of new applications. These include high brilliance light sources in a wide range of photon energies, electron cooling of ion beam and ERL-based electron-hadron colliders. Helmholtz-Zentrum Berlin started a feasibility study of GeV-scale multi-turn ERL-based light source (LS). This LS will work in diffraction limited regime in X-rays and with a short length of a light pulse in femtosecond region. The average and peak brightness will be at least an order of magnitude higher than synchrotron-based LS. In this work an overview of the future multi-turn light source is given. Modeling of the Beam Break Up instability is presented.

MOPPP040	Resistive Wall Heating of the Undulator in High Repetition Rate FELs	electron, wakefield, impedance, FEL	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.

MOPPP064	Challenges of Quasiperiodic APPLE Undulators	lattice, polarization, synchrotron, synchrotron-radiation	705
	J. Bahrdt HZB, Berlin, Germany S. Sasaki HSRC, Higashi-Hiroshima, Japan
	APPLE undulators have become workhorses in many synchrotron radiation facilities for the production of variably polarized light. In helical mode higher harmonics are not produced. In linear mode (horizontal, vertical, inclined) higher harmonics may contaminate the first harmonic and spoil the quality of experimental data. Planar undulators employing a quasiperiodic magnetic structure have been built and they are successfully operated at several places. The implementation of a quasiperiodic lattice in an APPLE undulator is more complicated since the device is operated in various modes of operation. The proposed APS-upgrade includes a quasiperiodic APPLE undulator which is intended to be operated in the range 2.4-27 keV. A detailed analysis of the magnetic and spectral performance of this device is presented.

MOPPP065	Effects of Geometrical Errors on the Field Quality in a Planar Superconducting Undulator	simulation, photon, status, electron	708
	J. Bahrdt HZB, Berlin, Germany J. Bahrdt, Y. Ivanyushenkov ANL, Argonne, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Short-period superconducting undulators are being developed at the Advanced Photon Source (APS). The first test device is being fabricated. It is using a relatively short magnetic structure that will be replaced with a longer magnet in the second device. High quality magnetic field with the phase errors at a level of 2 degrees rms were achieved in the prototype magnets due to very accurate winding of the superconducting coils on the formers machined to about 10-μm precision. Manufacturing meters-long undulator structures to such tolerances would be very difficult or even impossible. It is therefore important to understand the effects of the mechanical tolerances in the coil manufacture process on the quality of the magnetic field. The effects of geometrical errors in the position of a superconducting winding in a planar structure are simulated with the RADIA software package. A field profile of a long non-ideal undulator magnet is then built and analyzed in terms of the first and second field integrals as well as phase errors. The results of the systematic study of the geometrical errors on the field quality are presented in this paper.

MOPPP066	Calculated Spectra from Magnetic Field Measurements of 1.5 m Superconducting Undulator Coils	emittance, permanent-magnet, vacuum, storage-ring	711
	S. Casalbuoni, T. Baumbach, S. Gerstl, A.W. Grau, M. Hagelstein, T. Holubek, D. Saez de Jauregui Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany C. Boffo, W. Walter BNG, Würzburg, Germany
	In this contribution we report on the spectra calculated from the field measurements performed in a liquid helium bath of 1.5 m superconducting undulator coils. The coils are foreseen for a superconducting undulator demonstrator with a period length of 15 mm planned to be installed in ANKA middle 2012 and tested at the new beamline NANO for high resolution X-ray diffraction. The spectral performance at ANKA and at low emittance sources is compared with the competing cryogenic permanent magnet technology.

MOPPP067	In-vacuum, Cryogen-free Field Measurement System for Superconducting Undulator Coils	synchrotron, vacuum, insertion, insertion-device	714
	A.W. Grau, T. Baumbach, S. Casalbuoni, S. Gerstl, M. Hagelstein, T. Holubek, D. Saez de Jauregui Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
	The performance of superconducting insertion devices (IDs) depends strongly on the magnetic field quality. Before installing IDs in synchrotron light sources the characterization and precise measurements of their magnetic properties are of fundamental importance. Improvements in magnetic field measurement technology of conventional, i.e. permanent magnet based IDs, made significant progress during the last years and push the capabilities of synchrotron light sources. For superconducting IDs similar major developments are necessary. As a part of our R&D program for superconducting insertion devices we perform quality assessment of their magnetic field properties. This contribution describes details and challenges of the cryostat and measurement setup assembly to perform magnetic measurements of the local field and of the field integrals of superconducting undulator coils in a cold in-vacuum (cryogen free) environment. The focus will be on the outcome of the final acceptance test together with results of first tests performed with mock-up coils.

MOPPP068	Beam Heat Load and Pressure in the Superconducting Undulator Installed at ANKA	electron, vacuum, storage-ring, simulation	717
	S. Casalbuoni, S. Gerstl, A.W. Grau, T. Holubek, D. Saez de Jauregui Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
	A superconducting undulator has been installed in the ANKA (ANgstrom source KArlsruhe) storage ring since March 2005. The beam heat load and pressure on the cold bore were analyzed in the first two years of operation, during which the undulator was operated mainly with open gap. We report here on a larger statistic of beam heat load and pressure data collected in the last years with the undulator operated at different gap positions. The effects of vacuum leaks in the storage ring on the superconducting undulator operation are also described.

MOPPP070	Characterization of Vacuum Chamber Samples for Superconducting Insertion Devices	vacuum, storage-ring, insertion, insertion-device	723
	D. Saez de Jauregui, T. Baumbach, S. Casalbuoni, S. Gerstl, A.W. Grau, M. Hagelstein, C. Heske, T. Holubek, B. Krause, A. Seiler, S. Stankov, L. Weinhardt Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany C.Z. Antoine, Y. Boudigou CEA/IRFU, Gif-sur-Yvette, France C. Boffo BNG, Würzburg, Germany
	One of the key components of a superconducting insertion device is the ultra-high vacuum (UHV) chamber. In order to reach the accelerator UHV specifications, it is very important to control the surface chemical content and find proper cleaning procedures. To keep the geometric and resistive wall losses small, it is essential that the top few μm of the surface exhibits low roughness and good electrical conductivity at low temperatures. A 300-μm-thick 316L stainless steel foil, galvanized with a 30-μm copper layer, is used for the next superconducting undulator developed in a collaboration between KIT and BNG. We report here on different spectroscopic analyses as well as on residual resistivity ratio RRR measurements of the copper surface after cleaning procedures and annealing at various temperatures for different periods of time.

MOPPP072	Performance of APPLE-II Type Quasi-Periodic Undulator at HiSOR	radiation, polarization, electron, photon	729
	S. Sasaki, M. Arita, K. Goto, A. Miyamoto, T. Okuda HSRC, Higashi-Hiroshima, Japan
	A 1.8-m-long 78-mm-period quasi-periodic APLPE-II undulator was installed in the 700-MeV HiSOR storage ring of Hiroshima Synchrotron Radiation Center. At 23-mm nominal minimum gap, the fundamental photon energies are 3.1 eV, 6.5 eV, and 4.8 eV for horizontal linear, vertical linear, and circular polarization, respectively. The photon energies of observed fundamental and higher harmonic radiations are in good agreement with those of model calculations using measured undulator field and the HiSOR beam parameters. Also, observed flux thorough a slit and a grating monochromator was more than twice larger than that from previously installed 100-mm-period helical undulator for the whole range of radiation spectra. The feedforward COD correction was done to avoid the intensity fluctuation of photon beam in other BM beamlines due to the gap and phase motion of undulator. No fatal effect on the stored electron beam by installing the undulator was observed though a slight beam size change was observed at the minimum gap.

MOPPP074	Magnetic Field Measurement for a THz Undulator Using the Vibrating Wire Method	electron, radiation, laser, resonance	732
	S. Kashiwagi, H. Hama, F. Hinode, M. Kawai, X. Li, T. Muto, K. Nanbu, Y. Tanaka Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	Funding: This work is supported by the Ministry of Education, Science, Sports and Culture, Grant-in-Aid for Scientific Research (S), Contract #20226003. We constructed the undulator that is a basically a Halbach planer type for a generation of intense coherent terahertz radiation from the very short electron bunch. The period length of the undulator and the number of periods are 100 mm and 25, respectively. Its maximum magnetic field is 0.41 T and the K-value is 3.82 with 54 mm gap. The vibrating wire method is studied to measure the periodic magnetic field of the undulator. By measuring amplitudes and phases of standing waves excited on the wire by the Lorentz force between AC current and magnetic field, we can reconstruct the magnetic field distribution along the wire. The theoretical analysis has been performed for the THz undulator and derived a relation between a reproducibility of undulator field and the number of the harmonic mode to use for the reconstruction. A model experiment was demonstrated using 20cm wire and one pair of permanent magnet block. The theoretical study and the results of model experiment using the vibrating wire method will be shown in this conference.

MOPPP075	The Research on Magnetic Properties of Magnet for SSRF Cryogenic Permanent Magnet Undulator	cryogenics, permanent-magnet, radiation, synchrotron	735
	Y.Z. He, L. Wang, Q.G. Zhou SINAP, Shanghai, People's Republic of China
	The temperature coefficient of Br and Hci of Nd2Fe14B and Pr2Fe14B permanent magnet are about -0.1 K-1 and -0.6 K-1 respectively, the higher Br and Hci can be obtained at low temperature. By this theory, a cryogenic permanent magnet undulator(CPMU) may be designed, the maximum magnetic field and the Hci of permanent magnet increased 10-50% and 300-500% respectively, compared with the conventional undulators, the higher brightness X-rays and the more resistance to radiation of undulators can be obtained. The Pr2Fe14B permanent magnet has better potential magnetic properties than the Nd2Fe14B permanent magnet at low temperature for having no spin reorientation phenomenon. The permanent magnets are key “heart” magnetic components for cryogenic permanent magnet undulator, since January 2012, the research plan on magnetic properties of domestic permanent magnet for SSRF cryogenic permanent magnet undulator at low temperature by the support of Shanghai and Nation Nature science funds be started, the paper introduced research status of the item.

MOPPP076	Design Considerations for a Hybrid Undulator Applied in a Terahertz FEL Oscillator	FEL, 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.

MOPPP077	Heat Load Budget on TPS Undulator in Vacuum	synchrotron, radiation, synchrotron-radiation, vacuum	741
	J.C. Huang, J. Chen, C.-S. Hwang, F.-Y. Lin, Y.T. Yu NSRRC, Hsinchu, Taiwan
	The performance of an insertion device is limited by the magnet gap because a small gap affects the dynamic aperture and results in a short life time of the beam. An in-vacuum undulator is designed to have no vacuum chamber between the magnet arrays so to allow the entire magnet gap to be fully used for the dynamic aperture. An in-vacuum undulator can optimally minimize the gap to achieve continuous energy spectra. One problem of an undulator with a small gap is resistive wall heating by the image current. The heat load depends strongly on the injected mode in the storage ring; injection of multiple bunches might deteriorate the thermal performance for the magnet array. In this paper, we present a calculation of the heat load budget for a magnet array of an in-vacuum undulator of Taiwan Photon Source (TPS).

MOPPP078	Status of the First Planar Superconducting Undulator for the Advanced Photon Source	photon, controls, status, radiation	744
	Y. Ivanyushenkov, M. Abliz, K.D. Boerste, T.W. Buffington, C.L. Doose, J.D. Fuerst, Q.B. Hasse, M. Kasa, S.H. Kim, R. Kustom, E.R. Moog, D. Skiadopoulos, E. Trakhtenberg, I. Vasserman ANL, Argonne, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Superconducting technology offers the possibility of building short-period undulators for synchrotron light sources. Such undulators will deliver higher fluxes at higher photon energies to the light source user community. The Advanced Photon Source (APS) team is building the first superconducting planar undulator to be installed in the APS storage ring. The current status of the project is presented in this paper.

MOPPP080	New Concepts for Revolver Undulator Designs	insertion, insertion-device, vacuum, controls	750
	B.K. Stillwell, J.H. Grimmer, D.P. Pasholk, E. Trakhtenberg ANL, Argonne, USA M.B. Patil Impact Engineering Solutions, Brookfield, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Dynamic support of revolver undulator magnet structures presents a challenging mechanical problem. Some designs to date employ a support span connected at its ends to the undulator gap separation mechanism. However, this arrangement is problematic for long undulators operating at small gaps since the gap-dependent distortion of the magnet support span scales approximately with the cube of its length and exponentially with reduction in gap. Other designs have been demonstrated that utilize intermediate connections to a central magnet support span, but require additional stiffening members between that span and the magnet arrays. This arrangement is difficult to implement at the APS because of space constraints imposed by existing beam vacuum chambers. We have developed three revolver undulator concepts that provide an extremely rigid magnet support structure, precise rotational positioning, and wide gap tapering ability. Each of the concepts has advantages and disadvantages. All of the concepts are fully compatible with the existing APS-designed gap separation mechanism, which will greatly simplify testing and implementation.

MOPPP085	Single Electron Dynamic of Microwave Undulator	electron, FEL, 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.

MOPPP086	Praseodymium Iron-Boron Undulator With Textured Dysprosium Poles for Compact X-Ray FEL Applications	simulation, cryogenics, insertion, insertion-device	756
	R.B. Agustsson, Y.C. Chen, T.J. Grandsaert, A.Y. Murokh RadiaBeam, Santa Monica, USA F.H. O'Shea UCLA, Los Angeles, California, USA V. Solovyov BNL, Upton, Long Island, New York, USA
	Funding: DOE SBIR #97134S11-I Radiabeam Technologies is developing a novel ultra-high field short period undulator using two unconventional materials: praseodymium permanent magnets (PrFeB) and textured dysprosium (Tx Dy) ferromagnetic field concentrators. Both materials exhibit extraordinary magnetic properties at cryogenic temperatures, such as very large energy product and record high induction saturation, respectively. The proposed device combines PrFeB and Tx Dy in 3-D hybrid undulator geometry with sub-cm period and up to 3 Tesla pole tip field. Practical realization of these features will significantly surpass state-of-the-art and offer an ideal solution for the next generation of compact X-ray light sources. Initial simulations along with preliminary cryogenic measurements will be presented.

MOPPP088	Control of Nonlinear Dynamics by Active and Passive Methods for the NSLS-II Insertion Devices	polarization, insertion, insertion-device, electron	759
	J. Bengtsson, O.V. Chubar, C.A. Kitegi, T. Tanabe BNL, Upton, Long Island, New York, USA
	Funding: US DOE, Contract No. DE-AC02-98CH10886. Nonlinear dynamics effects from insertion devices (IDs) are known to affect the electron beam quality of third generation synchrotron light sources. In particular, beam lifetime, dynamical aperture and injection efficiency. Methods to model the IDs' non-linear effects are known, e.g. by second-order (in the inverse electron energy) kick maps. Methods to compensate these effects are known as well, e.g. by first-order thin or thick magnetic kicks introduced by "magic fingers," "L-shims," or "current strips." However, due to physical or technological constraints, these corrections are typically only partial. Therefore, a precise model is required for a correct minimization of the residual nonlinear dynamics effects for the combined magnetic fields of the ID and compensating magnets. We outline a systematic approach for such predictions, based on 3D magnetic field and local trajectory calculation in the ID by the Radia code, and particle tracking by Tracy-3. The optimal geometry for the compensating magnets is determined from these simulations using a combination of linear algebra and genetic optimization.

MOPPP089	Development of a PrFeB Cryogenic Undulator at NSLS-II	cryogenics, vacuum, synchrotron, permanent-magnet	762
	C.A. Kitegi, P. Cappadoro, O.V. Chubar, T.M. Corwin, H.C. Fernandes, D.A. Harder, P. He, G. Rakowsky, J. Rank, C. Rhein, T. Tanabe BNL, Upton, Long Island, New York, USA
	Recent cryogenic undulators use Praseodymium-Iron-Boron (PrFeB) magnets cooled down to 80K. The main drawn drawback of the PrFeB magnet grades developed so far are their relative low coercive field at ambient temperature, below 2 T which prevents PrFeB based cryogenic undulator from baking. Some precautions are required during the undulator assembling and shimming to ensure ultra high vacuum compatibility. However Hitachi Metal Industry (HMI) recently developed two different grades of PrFeB magnet with large coercive field but at the expense of the remanent field. The magnetization curves have been measured from 40 K up to 400 K to determine the field increase and to investigate the magnet withstanding to baking. An IVU prototype has also been baked. Magnetic measurements before and after baking are also presented.

MOPPP090	Spectral Performance of Segmented Adaptive-Gap In-Vacuum Undulators for Storage Rings	electron, vacuum, photon, radiation	765
	O.V. Chubar, J. Bengtsson, A. Blednykh, C.A. Kitegi, G. Rakowsky, T. Tanabe BNL, Upton, Long Island, New York, USA J.A. Clarke STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: US DOE, Contract No. DE-AC02-98CH10886. We propose an approach to the optimization of segmented in-vacuum undulators, in which different segments along an undulator may have different gaps and periods. This enables close matching between the gaps and the vertical "envelope" of electron beam motion in a storage ring straight section (carefully satisfying the associated vertical "stay clear" constraint) and, at the same time, precise tuning of all the segments to the same fundamental photon energy. Thanks to this, the vertical gaps in segments located closer to straight section center can be smaller than at extremities, and so the entire undulator structure can offer better magnetic performance, compared to the case of a standard undulator with constant gap (and period) over its length. We will present magnetic field, radiation flux, brightness and intensity calculation results for such segmented adaptive-gap in-vacuum undulators and demonstrate their gain in spectral performance over standard in-vacuum undulators, both for room-temperature and cryo-cooled realizations.

MOPPP091	Recent Developments at the DELTA THz Beamline	laser, electron, radiation, storage-ring	768
	P. Ungelenk, M. Bakr, H. Huck, M. Höner, S. Khan, R. Molo, A. Nowaczyk, A. Schick, M. Zeinalzadeh DELTA, Dortmund, Germany
	Funding: Work supported by DFG, BMBF, and by the Federal State NRW. During 2011, a new dedicated THz beamline has been constructed and commissioned at DELTA, a 1.5 GeV synchrotron light source operated by the TU Dortmund University. This beamline enables extracting and detecting coherent THz pulses caused by a laser-induced density modulation of the electron bunches. Ongoing experiments aim at characterizing the THz radiation as well as investigating the evolution of the density modulation over subsequent revolutions following the initial laser-electron interaction in an undulator.

MOPPR050	Design and Analysis of EPU XBPM in TPS	photon, synchrotron, synchrotron-radiation, radiation	894
	A. Sheng, C.M. Cheng, C.K. Kuan NSRRC, Hsinchu, Taiwan D. Shu ANL, Argonne, USA
	Several planer and elliptical polarized undulators (EPU) beam lines have been proposed and are to be built for Taiwan Photon Source (TPS) in National Synchrotron Research Center (NSRRC). Due to its complexity, with changing of vertical as well as horizontal deflection parameters (Kx and Ky), one finds that regular diamond bladed photon beam position monitor (XBPM) would not be sufficient to detect the center location of the undulator. A new conceptual design of EPU XBPM has been analyzed both in thermal as well as photon aspects. A prototype by taking advantage of fluorescent some of the diamond detectors has been designed and implemented in Taiwan Light Source (TLS) for testing. Some analysis and design scenarios are presented in this paper.

TUEPPB013	Development of an Advanced Computational Tool for Start-to-End Modeling of Next Generation Light Sources	electron, radiation, simulation, wakefield	1143
	J. Qiang, J.N. Corlett, C.E. Mitchell, C. F. Papadopoulos, G. Penn, R.D. Ryne, M. Venturini LBNL, Berkeley, California, USA
	Funding: Work supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Start-to-end simulation plays an important role in designing next generation light sources. In this paper, we present recent progress in further development and application of the parallel beam dynamics code, IMPACT, towards the fully start-to-end, multi-physics simulation of a next generation X-ray FEL light source. We will discuss numerical methods and physical models used in the simulation. We will also present some preliminary simulation results of a beam transporting through photoinjector, beam delivery system, and FEL beamlines.

TUEPPB015	Generation of Narrow-Band Coherent Tunable Terahertz Radiation using a Laser-Modulated Electron Beam	laser, electron, radiation, bunching	1146
	M.P. Dunning, C. Hast, E. Hemsing, R.K. Jobe, D.J. McCormick, J. Nelson, T.O. Raubenheimer, K. Soong, Z.M. Szalata, D.R. Walz, S.P. Weathersby, D. Xiang SLAC, Menlo Park, California, USA
	Funding: Work supported by US DOE contract DE-AC02-76SF00515. The technical layout and initial results of an experiment to generate narrow-band, coherent, tunable terahertz (THz) radiation through the down-conversion of the frequency of optical lasers using a laser-modulated electron beam are described. In this experiment a 120 MeV electron beam is first energy modulated by two lasers with different wavelengths. After passing through a dispersive section, the energy modulation is converted into a density modulation at THz frequencies. This density-modulated beam will be used to generate narrow-band THz radiation using a coherent transition radiator inserted into the beam path. The central frequency of the THz radiation can be tuned by varying the wavelength of one of the two lasers or the energy chirp of the electron beam. The experiment is being performed at the NLCTA at SLAC, and will utilize the existing Echo-7 beamline, where echo-enabled harmonic generation (EEHG) was recently demonstrated.

TUPPC025	Solaris Storage Ring Lattice Optimization with Strong Insertion Devices	lattice, optics, insertion, storage-ring	1218
	A.I. Wawrzyniak, C.J. Bocchetta Solaris, Kraków, Poland M. Eriksson, S.C. Leemann MAX-lab, Lund, Sweden
	Funding: Work supported by the European Regional Development Fund within the frame of the Innovative Economy Operational Program: POIG.02.01.00-12-213/09 The Solaris synchrotron light facility under construction in Kraków will be a replica of the 1.5 GeV storage ring of MAX IV. This compact 3rd generation light source has been designed to have an emittance of 6 nmrad and operate with 500 mA stored current for VUV and soft X-Rays production. The lattice design consists of 12 Double Bend Achromats (DBA) with each DBA cell integrated into one solid iron block. Twelve 3.5 m long straight sections are available of which 10 will be equipped in various insertion devices. These devices will differ from those adopted by MAX IV. For X-ray production one or more superconducting wigglers will be used, while APPLE II type undulators will be used for variable polarised light production. The linear and nonlinear lattice dynamics have been studied with these perturbing insertion devices included in the ring and results are presented in this paper.

TUPPC075	Study of Nonlinear Beam Dynamics Effects for DEPU at SSRF	polarization, electron, photon, focusing	1347
	M. Zhang, Q.G. Zhou SINAP, Shanghai, People's Republic of China
	A pair of EPUs (DEPU) with the period 58mm and 148mm, covering the energy ranges from 20 to 200eV and 200 to 2000eV of arbitrary polarized light, will be developed for the SSRF soft X-ray beam line for ARPES and PEEM. The effects of DEPU to tune-shift produced by the nonlinear beam dynamics are studied and the results are presented in this paper. The corresponding magnet field shimming technology to reduce these effects is also investigated.

TUPPD036	Novel Designs for Undulator Based Positron Sources	positron, target, photon, damping	1485
	M. Jenkins Cockcroft Institute, Warrington, Cheshire, United Kingdom I.R. Bailey, M. Jenkins Lancaster University, Lancaster, United Kingdom
	At least three proposed future colliders(ILC, CLiC and LHeC) require a positron source with a yield greater than 10¹⁴ e+/s. An undulator based positron source has the potential to provide the required yield. This design generates gamma rays by using a high energy electron beam traveling through a superconducting helical undulator. The gamma rays then pair produce in a titanium alloy target to produce positrons. This is the ILC baseline positron source. Two drawbacks to the undulator-based positron source are that it couples the positron source to the electron beam operation and that it exhibits a low conversion efficiency of photons to positrons. A self-seeding undulator-based positron source has been proposed. This starts with a low intensity positron beam which travels through the undulator to produce more positrons which are recirculated through the source to increase the intensity until the design yield is achieved. Multiple targets have been added to increase the conversion efficiency of the positron source. In this study I present simulation results for such a design and consider the feasibility of this design at the ILC, CLiC or LHeC.

TUPPP005	LUNEX5: A French FEL Test Facility Light Source Proposal	FEL, laser, emittance, electron	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.

TUPPP007	Modifications to the Machine Optics of BESSY II Necessitated by the EMIL Project	optics, cryogenics, dipole, storage-ring	1614
	P.O. Schmid, J. Bahrdt, T. Birke, R. Follath, P. Kuske, D. Simmering, G. Wüstefeld HZB, Berlin, Germany
	The Helmholtz Zentrum Berlin and the Max Planck Society are going to build a new dedicated X-ray beam line at the synchrotron source light source BESSY II which will be used for analyzing materials for renewable energy generation. The new large scale project has been dubbed EMIL. In this document we present the modifications to the machine optics and to what extent these changes affect the performance of BESSY II.

TUPPP008	Recent Results From the Short-Pulse Facility at the DELTA Storage Ring	laser, radiation, electron, synchrotron	1617
	A. Schick, M. Bakr, H. Huck, M. Höner, S. Khan, R. Molo, A. Nowaczyk, P. Ungelenk, M. Zeinalzadeh DELTA, Dortmund, Germany
	Funding: Work supported by DFG, BMBF and by the Federal State NRW. At the 1.5 GeV synchrotron light source DELTA, operated by the TU Dortmund University, a new facility for ultrashort pulses in the VUV and THz regime is currently under commissioning. Here, the interaction of an intense, ultrashort laser pulse, co-propagating with the electrons in an optical klystron, leads to coherent synchrotron radiation at harmonics of the incident laser wavelength. The aim of the present commissioning steps is to extend the emitted wavelength down to about 50 nm, enabling femtosecond-resolved pump-probe experiments in the VUV regime. Other issues include increasing the photon flux by optimizing the laser-electron interaction and improving the stability and ease of operation of the source.

TUPPP009	Status of the PETRA III Upgrade	shielding, radiation, vacuum, site	1620
	M. Bieler, K. Balewski, W. Drube, J. Keil, A. Kling DESY, Hamburg, Germany
	Since 2010 PETRA III, a third generation light source at DESY, has been running as a user facility, with all 14 undulator beam lines operational since autumn 2011. In order to fulfill the request for more beam time after the shut down of DORIS at the end of 2012, it was decided to add two additional halls at PETRA III, each housing 5 additional beam lines. Next to these two new halls about 100 m of the accelerator will be completely remodeled to install additional undulators. The upgrade should be accomplished during a 6 month shut down in 2013. In order to minimize this down time, it was decided to keep the existing accelerator tunnel in place. This has impact both on the mechanical connection between the accelerator and the experimental floor and on the design of the optical beam lines in the tunnel. In this paper the layout of the upgraded accelerator will be shown. The design status of the major components for the upgrade will be presented.

TUPPP016	Recent Development of PF Ring and PF-AR	injection, polarization, linac, vacuum	1641
	Y. Tanimoto, T. Aoto, S. Asaoka, K. Endo, K. Haga, K. Harada, T. Honda, Y. Honda, M. Izawa, Y. Kobayashi, A. Mishina, T. Miyajima, H. Miyauchi, S. Nagahashi, N. Nakamura, T. Nogami, T. Obina, T. Ozaki, C.O. Pak, H. Sakai, S. Sakanaka, H. Sasaki, Y. Sato, K. Satoh, M. Shimada, K. Shinoe, T. Shioya, M. Tadano, T. Tahara, T. Takahashi, R. Takai, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, M. Yamamoto KEK, Ibaraki, Japan H. Takaki ISSP/SRL, Chiba, Japan
	After the earthquake of March 11, two light sources of KEK, PF ring and PF-AR, have recovered the regular operation from October, 2011. We installed tandem variably-polarized undulators at PF ring in 2009. Recently, the orbit switching system has been completed with sufficient feed-forward orbit compensation at 10-Hz. PF ring is usually operated at 450 mA with a top-up injection using the pulsed sextupole magnet instead of the conventional kicker magnets. The transverse and longitudinal instabilities are suppressed by a digital feedback system using the iGp signal processor. In the longitudinal direction, we observed unstable quadrupole mode oscillation which could not be controlled by the feedback system. We had applied the phase modulation of the main RF cavity to stabilize the quadrupole oscillation before. Old-type RF-shielded gate valves damaged by the earthquake were removed from the ring during the summer maintenance. In the operation after autumn, the quadrupole oscillation can be cured by dividing the bunch train of partial-filling. Without the phase modulation, the effective brightness of SR beam has been improved especially at beam lines of finite dispersion function.

TUPPP021	Orbit Stability at ALBA	insertion, insertion-device, wiggler, booster	1653
	M. Muñoz, G. Benedetti, D. Einfeld, J. Marcos, Z. Martí CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain
	The synchrotron light source ALBA is in the final stage of the Storage Ring commissioning, with the beamline commissioning well under way. In the month of beam line commissioning, the storage ring has provided an stable beam, with horizontal and vertical stabilities better than the micrometer in both planes in DC and a good reproducibility of the beam position day by day. In this paper we review the performance of the Slow Orbit Feedback, the changes in orbit due to insertion devices, as well as the first measurement using the 10 kHz sampling mode of the Libera BPMs, together with the status of the implementation of the Fast Orbit Feedback system.

TUPPP032	Use of Multi-objective Methods for Choosing Undulators for Storage Rings	brightness, photon, target, storage-ring	1680
	M. Borland ANL, Argonne, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Users of storage ring light sources generally rely on undulators to provide the highest brightness. Choice of the optimal undulator period is complicated by the fact that users do not operate at a single photon energy or place equal weight on operation at all photon energies of interest. In addition, some users may be best served by a double- or triple-period revolver device. In this paper, we present a method of narrowing the choice of undulator periods based on multi-objective techniques. Applications are shown in the context of the Advanced Photon Source Upgrade.

TUPPP038	Electron Beam Collimation for the Next Generation Light Source	collimation, gun, linac, impedance	1695
	C. Steier, P. Emma, H. Nishimura, C. F. Papadopoulos, F. Sannibale LBNL, Berkeley, California, USA
	Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The Next Generation Light Source will deliver high (MHz) repetition rate electron beams to an array of free electron lasers. Because of the significant average current in such a facility, effective beam collimation is extremely important to minimize radiation damage to undulators, prevent quenches of superconducting cavities, limit dose rates outside of the accelerator tunnel and prevent equipment damage. This paper describes the conceptual design of the collimator system, as well as the results of simulations to test its effectiveness.

TUPPP045	Creation of FELWI using Large Amplification Regime	electron, FEL, 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	vacuum, FEL, 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	FEL, laser, electron, bunching	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	FEL, electron, photon, laser	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.

TUPPP056	Study of the Energy Chirp Effects on Seeded FEL Schemes at SDUV-FEL	FEL, electron, radiation, laser	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	FEL, laser, radiation, simulation	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	FEL, cavity, radiation, 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	linac, gun, electron, FEL	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.

TUPPP066	CLARA - A Proposed New FEL Test Facility for the UK	FEL, electron, laser, 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.

TUPPP067	Collimation System Design and Performance for the SwissFEL	collimation, linac, wakefield, electron	1753
	F. Jackson, J.-L. Fernández-Hernando STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom D. Angal-Kalinin Cockcroft Institute, Warrington, Cheshire, United Kingdom H.-H. Braun, S. Reiche Paul Scherrer Institut, Villigen, Switzerland
	Electron beam collimation in the SwissFEL is required for protection of the undulators against radiation damage and demagnetization. The design for the SwissFEL collimation for the hard X-ray undulator (Aramis) includes transverse collimation in the final accelerating linac sections, plus an energy collimator in a post-linac chicane. The collimation system must provide efficient protection of the undulator for various machine modes providing varied final beam energy to the undulator. The performance of the transverse and energy collimation design is studied in simulations including evaluation of the transverse collimation for various beam energies and the effect of grazing particles on the energy collimator. Collimator wakefields are also considered.

TUPPP069	A Compact, Modular Electron Beam Delay Line for Use in Novel Free-Electron Laser Schemes	quadrupole, FEL, 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).

TUPPP073	Machine Parameter Studies for an FEL Facility Using STAFF	FEL, photon, 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.

TUPPP079	Design Alternatives for a Free Electron Laser Facility	FEL, linac, 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	FEL, 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	radiation, FEL, 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, FEL, 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.

TUPPP087	Commissioning of the Fritz Haber Institute Mid-IR FEL	FEL, wiggler, electron, linac	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.

TUPPR002	Simulations of Positron Polarization in the Undulator-Based Source	positron, polarization, electron, photon	1810
	A. Ushakov, O.S. Adeyemi, V.S. Kovalenko, L.I. Malysheva, G.A. Moortgat-Pick University of Hamburg, Hamburg, Germany A.F. Hartin DESY, Hamburg, Germany S. Riemann, F. Staufenbiel DESY Zeuthen, Zeuthen, Germany
	Funding: This work is supported by the German Federal Ministry of Education and Research, Joint Research Project R&D Accelerator "Spin Management", contract number 05H10GUE The generation of an intense and highly polarized positron beam is a challenge. The design for the International Linear Collider proposes a positron source based on a helical undulator located at the end of the electron linac. This design allows us to utilize a high energy linear accelerator with both electron and positron beams polarized. The polarization of the positron beam can be enhanced using a photon collimator. The optimization of positron yield and polarization for a wide energy range has been studied for different undulator parameters and collimator designs, taking into account realistic parameters for the capture section. In particular, the effects of misalignment and tolerances are considered.

TUPPR040	Update on ILC Positron Source Study at ANL	positron, polarization, photon, electron	1906
	W. Liu, W. Gai ANL, Argonne, USA
	As the new ILC baseline has moved the positron production to the end of electron main linac, both the drive beam energy and beamline layouts have also been changed for the positron source. Now the drive beam energy will be varying from 150GeV to 250GeV and 500GeV (for TeV upgrade) as the colliding center of mass (CM) energy changes. Systematic studies on the performance of positron source under different running scenarios have been done at ANL and the results are presented in this paper.

TUPPR041	Update on ILC Positron Source Start-to-End Simulation	positron, electron, lattice, linac	1909
	W. Liu, W. Gai ANL, Argonne, USA
	As a result of the changes in the new ILC base line, there are many changes in the positron source beamline layouts and thus a new lattice design is required. According to the changes in the ILC baseline, a new lattice design for the ILC positron source has been developed at ANL. In this paper, both the new ILC positron source beamline lattice and the corresponding start to end simulation results are presented.

TUPPR042	On the Polarization Upgrade of ILC Undulator-based Positron Source	polarization, positron, photon, electron	1912
	W. Liu, W. Gai ANL, Argonne, USA S. Riemann DESY, Hamburg, Germany A. Ushakov University of Hamburg, Hamburg, Germany
	The current nominal polarization for ILC undulator based positron source is 30% without photon collimators. In order to improve the effective luminosity, an upgrade of positron source with higher polarization is required. Some studies on the upgrade options have been done at both DESY and ANL, and the results are presented in this paper.

WEYB01	The SPring-8 Angstrom Compact Free Electron Laser (SACLA)	laser, electron, emittance, FEL	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]

WEOBB03	Computation of the Wigner Distribution for Undulator Radiation	radiation, electron, synchrotron, brightness	2149
	I.V. Bazarov, A.D. Gasbarro CLASSE, Ithaca, New York, USA
	In the effort to optimize brightness in synchrotron radiation sources, questions arise as to the most desirable electron beam parameters given a particular insertion device. With a detailed understanding of the distribution of emitted photons, the electron beam profile can be effectively matched. We have developed tools which, by way of the Wigner distribution, compute the phase space of photons radiated by an electron bunch. An explanation is provided of the workings of the code itself with mention of important algorithms that have been implemented. We demonstrate via numerical examples the Wigner distributions of the undulator radiation. In particular, it is shown that the phase space of light differs appreciably from the Gaussian distribution assumed in many analytical expressions and, therefore, the more thorough approaches should be used for computation of related quantities.
	Slides WEOBB03 [2.555 MB]

WEEPPB006	LCLS Femto-second Timing and Synchronization System Update	laser, controls, LLRF, EPICS	2176
	G. Huang, J.M. Byrd, R.B. Wilcox LBNL, Berkeley, California, USA A.R. Fry, B.L. Hill SLAC, Menlo Park, California, USA
	Femto second timing and synchronization system has been installed on LCLS operation for 2 years. The requirement of more receiver at different location of the experimental hall urge us to develop a new version of receiver chassis and sync-head. Two sets of the new receiver chassis has been installed to the SXR and CXI end station. To help end user the diagnose the system, a intermediate GUI is developed to show some diagnostic information.

WEPPC005	Parts Management during Fabrication at the European XFEL	controls, cavity, cryomodule, niobium	2212
	L. Hagge, J.A. Dammann, S. Eucker, A. Herz, J. Kreutzkamp, D. Käfer, D. Szepielak, N. Welle DESY, Hamburg, Germany
	This presentation describes policies and methods for parts management during fabrication at the European XFEL. The objective is to provide procedures for reliably gathering, recording, processing and archiving the complete mandatory fabrication information. The solution is a foundation for conducting Quality Assurance and Quality Control (QA/QC), as it ensures that acceptance tests are recorded, signed-off and followed-up in a reliable and orderly way. It achieves compliance with legal regulations in certain areas. One example is the pressurized equipment directive (PED), which for certain (parts of) equipment requires that the complete fabrication and usage history is tracked throughout the entire lifespan of the XFEL facility. In addition, the solution provides a basis for building the necessary documentation for later installation, operation and maintenance activities. The solution is established in the series production of several accelerator components. It uses DESY’s Engineering Data Management System as central collaboration and documentation platform.

WEPPD008	Recondenser Performance: Impact on the Superconducting Undulator Magnet at Argonne National Laboratory	ion, cryogenics, background, factory	2513
	J.M. Pfotenhauer, D.M. Schick UW-Madison/EP, Madison, Wisconsin, USA
	Funding: This work is supported by Argonne National Laboratory, subcontract number 9F-31982. The current sharing temperature of 6.5 K for the superconducting undulator magnet being developed at Argonne National Laboratory drives the thermal design of the magnet’s cooling system. In order to remain below the current sharing temperature, a thermo-siphon cooling loop is being developed to sweep the anticipated heat load away from the magnet windings and deposit it in the associated liquid helium reservoir located above the magnet. Performance of the magnet’s cooling system is crucially dependent on the ability of the re-condenser to maintain the reservoir’s saturation temperature near 4 K, despite thermal stratification and slowly varying thermal profiles within the vapor region above the liquid in the reservoir. Here we report the results of an experimental investigation of the impact of various geometric configurations for the re-condenser and the thermal resistance associated with the film layer at the re-condensing surface, on the time-varying saturation temperature within the helium reservoir. The resulting temporal thermal variations in the superconducting winding are highlighted as well as the impact they have on the magnet’s stability.

WEPPD032	Heat Load Studies in Target and Collimator Materials for the ILC Positron Source	photon, positron, polarization, target	2576
	F. Staufenbiel, S. Riemann DESY Zeuthen, Zeuthen, Germany O.S. Adeyemi, V.S. Kovalenko, L.I. Malysheva, G.A. Moortgat-Pick, A. Ushakov University of Hamburg, Hamburg, Germany
	An intense polarized positron beam for future linear colliders can be produced using a high power beam of circularly polarized photons which penetrates a thin titanium-alloy target. The degree of polarization can be increased by cutting the outer part of the photon beam generated in a helical undulator using a collimator in front of the target. However, the photon beam induces substantial heat load and stress inside the target and collimator materials. In order to avoid failure of these components the stress evolution has been simulated. The results as well as the corresponding material arrangements for the photon collimator design are presented.

WEPPD052	Compression and Synchronization of MeV Scale Subpicosecond Electron Beams in a THz IFEL Interaction	electron, laser, simulation, space-charge	2636
	J.T. Moody, R.K. Li, P. Musumeci, C.M. Scoby, H.L. To UCLA, Los Angeles, California, USA
	Recent development of MW peak power THz sources from efficient optical rectification of broadband IR pulses by pulse front tilting has made available laser locked single cycle THz pulses suitable for compression and laser-synchronization of photoinjector generated subpicosecond electron beams. Three dimensional simulations have shown that a waveguided 8 pulse THz train can be used to interact with a sub picoseconds electron beam in an undulator to achieve compression and laser synchronization. We present a THz pulse train source currently under development at UCLA PBPL as well as detailed 3 dimensional simulations including the effect of the interaction on transverse beam quality. DOE-BES No. DE-FG02-92ER40693 and DOE-BES No. DE-FG02-07ER46272

WEPPD053	The LLNL/UCLA High Gradient Inverse Free Electron Laser Accelerator	electron, laser, acceleration, simulation	2639
	J.T. Moody, P. Musumeci UCLA, Los Angeles, California, USA G.G. Anderson, S.G. Anderson, M. Betts, S.E. Fisher, D.J. Gibson, A.M. Tremaine, S.S.Q. Wu LLNL, Livermore, California, USA
	Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. We describe the Inverse Free Electron Accelerator currently under construction at Lawrence Livermore National Lab. Upon completion of this accelerator, high brightness electrons generated in the photoinjector blowout regime and accelerated to 50 MeV by S-band accelerating sections will interact with > 4 TW peak power Ti:Sapphire laser in a highly tapered 50 cm undulator and experience an acceleration gradient of >200 MeV/m. We present the final design of the accelerator as well as the results of start to end simulations investigating preservation of beam quality and tolerances involved with this accelerator.

WEPPP032	Inverse Free Electron Laser Acceleration Using Ultra-fast Solid State Laser Technology	laser, simulation, acceleration, electron	2795
	S.G. Anderson, G.G. Anderson, S.M. Betts, S.E. Fisher, D.J. Gibson, A.M. Tremaine, S.S.Q. Wu LLNL, Livermore, California, USA J.T. Moody, P. Musumeci UCLA, Los Angeles, California, USA
	Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. We present a theoretical and computational study of the application of Ti:Sapphire laser technology to Inverse Free Electron Laser (IFEL) accelerators. Specifically, the regime in which the number of undulator periods is comparable to the number of cycles in the laser pulse is investigated and modifications to the IFEL accelerator equations and laser requirements are given. 1-D and 3-D simulations are used to study the IFEL interaction in this regime. In addition, the effects of non-Gaussian laser pulses, and astigmatic aberrations in the laser focus are analyzed. Finally, the tools developed for this study are applied to the LLNL/UCLA IFEL experiment, and potential future IFEL designs.

WEPPP036	Undulator Commissioning for a High-Energy-Gain Inverse Free Electron Laser Experiment	laser, electron, simulation, acceleration	2804
	J.P. Duris, R.K. Li, P. Musumeci, E.W. Threlkeld UCLA, Los Angeles, California, USA
	Funding: This work was supported by DOE grant DE-FG02-92ER40693 and Defense of Threat Reduction Agency award HDTRA1-10^-1-0073. We present the construction and measurement details of a strongly tapered helical undulator for the Rubicon Inverse Free Electron Laser (IFEL) experiment. Results of the magnetic field measurements are presented, and these are used to produce simulations of the expected performance of the experiment. Finally, a study of the tolerances on the input parameters of the experiment is presented.

WEPPR082	The Collective Effects of Long Straight Sections (LSSs) in the Advanced Photon Source Upgrade	impedance, storage-ring, collective-effects, injection	3120
	Y.-C. Chae, L.H. Morrison ANL, Argonne, USA
	Funding: Work supported by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06CH11357. The Advanced Photon Source is a 7-GeV hard x-ray synchrotron light source. The APS Upgrade specifies additional beamlines delivering higher brightness and flux as well as for the short-pulse x-ray (SPX). In order to fulfill these demands we plan to provide long straight sections (LSS), for which the total length of the insertion devices is increased to 7.7m. The long straight section also helps in implementing the SPX scheme without removing insertion devices. However, the impedance of the LSS may reduce the single-bunch current of 16 mA per bunch delivered to the users during hybrid fill. We estimate the effect of LSS impedance on the bunched beam current and propose an impedance optimization of the undulator chamber with a small gap.

WEPPR086	Computed Wake Field Effects from Measured Surface Roughness in the Walls of the Cornell ERL	wakefield, vacuum, scattering, impedance	3132
	M.G. Billing, G.H. Hoffstaetter, C.E. Mayes, K.W. Smolenski, H.A. Williams CLASSE, Ithaca, New York, USA
	Funding: Work supported by the NSF ERL Phase 1B Cooperative Agreement (DMR-0807731) Wake fields arise from the discontinuities in a smooth vacuum chamber and will cause energy spread in the passing bunch. In an energy recovery linac (ERL), the spent bunches are decelerated before they are dumped to reuse the beam’s energy for the acceleration of new bunches. While the energy spread accumulated from wakes before deceleration is small compared to the beam’s energy after full acceleration, it becomes more important relatively as the beam’s energy decreases.* Thus, in an ERL wake fields can produce very significant energy spread in the beam as it is decelerated to the energy of the beam dump. We report on calculations of wake fields due to the roughness of the surface of the vacuum chamber walls as it affects the Cornell ERL design. These calculations include the effects from the measured roughness for real vacuum chamber wall surfaces. * M. Billing, “Effect of Wake Fields in an Energy Recovery Linac”, PAC’09, Vancouver, BC, Canada, 4-8 May 2009.

WEPPR098	Two Dimensional Impedance Analysis of Segmented IVU	impedance, vacuum, simulation, storage-ring	3168
	A. Blednykh, G. Bassi, J. Bengtsson, O.V. Chubar, C.A. Kitegi, T. Tanabe BNL, Upton, Long Island, New York, USA
	Funding: Work supported by DOE contract No: DE-AC02-98CH10886 Segmented Adaptive-Gap In-Vacuum Undulator (IVU) with variable magnetic gap along z-axis is considered as an alternative to the Constant Gap IVU (7mm gap) for the NSLS-II storage ring. The length of the Constant Gap IVU for a given minimum gap is limited by the beam stay clear aperture. With the new conceptual design of IVU the magnetic gap can be varied along z-axis and its minimum gap can be reduced down to 5.25mm in the center of the structure for the same stay clear aperture. Beam impedance becomes an important issue since the new design consists of several magnet gaps. Wakepotentials and impedances have been analyzed for a new type of IVU and the results compared with data for the reference geometry which is the Constant Gap IVU.

THPPD008	Status of the PAL-XFEL Undulator System	controls, FEL, 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.

THPPR002	The Undulator Control System for the European XFEL	controls, photon, quadrupole, electron	3966
	S. Karabekyan, A. Beckmann, J. Pflüger European XFEL GmbH, Hamburg, Germany N. Burandt, J. Kuhn Beckhoff Automation GmbH, Verl, Germany A. Schöps DESY, Hamburg, Germany
	The European XFEL project is a 4th generation light source. The first beam will be delivered in the beginning of 2015 and will produce spatially coherent ≤80fs short photon pulses with a peak brilliance of 10³²–10³⁴ photons/s/mm²/mrad²/0.1% BW in the energy range from 0.26 to 29 keV at electron beam energies of 10.5 GeV, 14 GeV, or 17.5 GeV . The Undulator systems are used to produce photon beams for SASE 1, SASE 2 and SASE 3. Each undulator system consists of an array of undulator cells installed in a row along the electron beam. A single undulator cell itself consists of a planar undulator, a phase shifter, magnetic field correction coils and a quadrupole mover. This paper describes the design of the entire undulator control system including local and global control. It presents a concept of integration of the undulator control into the accelerator control system as well as into the experiment control.

THPPR033	Tests and Measurements with the Embedded Radiation-monitor-system Prototype for Dosimetry at the European XFEL	radiation, linac, electron, neutron	4041
	F. Schmidt-Föhre, D. Nölle, R. Susen, K. Wittenburg DESY, Hamburg, Germany
	A new Embedded Radiation-Monitor-System is currently under development for use in the upcoming European XFEL, that is being built at a length of approx. 3.4 km between the campus of the Deutsches Elektronen-Synchrotron DESY at Hamburg and Schenefeld at Schleswig-Holstein. Most of the electronic systems cabinets for machine control, diagnostics and safety of the XFEL will be located inside the accelerator tunnel. To prevent significant radiation damage at electronic systems in certain sections of the XFEL, all electronic cabinets inside the tunnel will be sufficiently shielded according to pre-estimated radiation levels. In addition, accumulated dose inside these electronic cabinets and in undulator regions will be monitored for the impact of Gamma- and Neutron-radiation by a new radiation monitor system. Life cycle estimations for these electronics and the undulators will provide safety limits for correct function and in time part exchange due to radiation, before significant radiation damage occurs. A prototype of the Gamma radiation-monitor system section has been successfully designed and tested at the DESY Linac II. Prototype tests and according measurements will be presented.

FRXAB01	Symplectic Tracking and Compensation of Dynamic Field Integrals in Complex Undulator Structures	permanent-magnet, simulation, polarization, dipole	4165
	J. Bahrdt, G. Wüstefeld HZB, Berlin, Germany
	This presentation covers analytical models that describe the interaction of an electron beam with the magnetic field of undulators. Analytic approximations to the Hamilton-Jacobi equation yield generating functions useful for particle tracking and therefore efficient simulation. Analytic expressions for kick maps of APPLE II undulators are presented as well. Passive and active shimming schemes including magic fingers and current sheets are also modeled. Applications at BESSY II are discussed which ensure efficient injection during top-up to satisfy machine protection and radiation safety requirements.
	Slides FRXAB01 [1.922 MB]

FRYAP01	The Future of X-ray FELs	FEL, 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

Simulation and Measurement of Beam Loss in the Narrow-Gap Undulator Straight Section of the Advanced Photon Source Storage Ring

simulation, vacuum, radiation, neutron

106

J.C. Dooling, M. Borland
ANL, Argonne, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02-06CH11357.
Simulations indicate the removal of a scraper/collimator in the Sector 37 straight section (SS) of the Advanced Photon Source storage ring (SR) results in increased beam loss in the remaining narrow-gap, insertion device SS, ID4. Modeling with elegant provides loss distributions in the 5-mm aperture vacuum chamber of ID4 and includes the effects of rf system muting and quantum excitation in the bunch. The loss distributions are then used as input to a MARS model of the SS that includes undulator geometry. ID4 has been instrumented with additional monitoring to capture beam loss events, particularly beam dumps. Cerenkov detectors and fiber-optic cable bundles are used to capture temporal profiles of beam loss events. Beam dumps deliver 2600 J to the vacuum chamber and surrounding hardware including undulators. Data indicate a variety of temporal profiles occur during the beam dumps, with the shortest lasting 6 microseconds, FWHM (<2 turns). Such high power and power densities can lead to physical damage of vacuum components if not handled correctly. Touschek scattering loss is also a concern for undulator demagnetization. Comparison of modeling and measurements will be presented.

MOPPD038

Simulation Study of Electron Response Amplification in Coherent Electron Cooling

electron, ion, bunching, FEL

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.

MOPPP016

Feasibility Study of an ERL-based GeV-scale Multi-turn Light Source

linac, brilliance, cryomodule, optics

604

Y. Petenev, T. Atkinson, A.V. Bondarenko, A.N. Matveenko
HZB, Berlin, Germany

A new generation of particle accelerators based on an Energy Recovery Linac (ERL) is a promising tool for a number of new applications. These include high brilliance light sources in a wide range of photon energies, electron cooling of ion beam and ERL-based electron-hadron colliders. Helmholtz-Zentrum Berlin started a feasibility study of GeV-scale multi-turn ERL-based light source (LS). This LS will work in diffraction limited regime in X-rays and with a short length of a light pulse in femtosecond region. The average and peak brightness will be at least an order of magnitude higher than synchrotron-based LS. In this work an overview of the future multi-turn light source is given. Modeling of the Beam Break Up instability is presented.

MOPPP040

Resistive Wall Heating of the Undulator in High Repetition Rate FELs

electron, wakefield, impedance, FEL

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.

MOPPP064

Challenges of Quasiperiodic APPLE Undulators

lattice, polarization, synchrotron, synchrotron-radiation

705

J. Bahrdt
HZB, Berlin, Germany
S. Sasaki
HSRC, Higashi-Hiroshima, Japan

APPLE undulators have become workhorses in many synchrotron radiation facilities for the production of variably polarized light. In helical mode higher harmonics are not produced. In linear mode (horizontal, vertical, inclined) higher harmonics may contaminate the first harmonic and spoil the quality of experimental data. Planar undulators employing a quasiperiodic magnetic structure have been built and they are successfully operated at several places. The implementation of a quasiperiodic lattice in an APPLE undulator is more complicated since the device is operated in various modes of operation. The proposed APS-upgrade includes a quasiperiodic APPLE undulator which is intended to be operated in the range 2.4-27 keV. A detailed analysis of the magnetic and spectral performance of this device is presented.

MOPPP065

Effects of Geometrical Errors on the Field Quality in a Planar Superconducting Undulator

simulation, photon, status, electron

708

J. Bahrdt
HZB, Berlin, Germany
J. Bahrdt, Y. Ivanyushenkov
ANL, Argonne, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Short-period superconducting undulators are being developed at the Advanced Photon Source (APS). The first test device is being fabricated. It is using a relatively short magnetic structure that will be replaced with a longer magnet in the second device. High quality magnetic field with the phase errors at a level of 2 degrees rms were achieved in the prototype magnets due to very accurate winding of the superconducting coils on the formers machined to about 10-μm precision. Manufacturing meters-long undulator structures to such tolerances would be very difficult or even impossible. It is therefore important to understand the effects of the mechanical tolerances in the coil manufacture process on the quality of the magnetic field. The effects of geometrical errors in the position of a superconducting winding in a planar structure are simulated with the RADIA software package. A field profile of a long non-ideal undulator magnet is then built and analyzed in terms of the first and second field integrals as well as phase errors. The results of the systematic study of the geometrical errors on the field quality are presented in this paper.

MOPPP066

Calculated Spectra from Magnetic Field Measurements of 1.5 m Superconducting Undulator Coils

emittance, permanent-magnet, vacuum, storage-ring

711

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

In this contribution we report on the spectra calculated from the field measurements performed in a liquid helium bath of 1.5 m superconducting undulator coils. The coils are foreseen for a superconducting undulator demonstrator with a period length of 15 mm planned to be installed in ANKA middle 2012 and tested at the new beamline NANO for high resolution X-ray diffraction. The spectral performance at ANKA and at low emittance sources is compared with the competing cryogenic permanent magnet technology.

MOPPP067

In-vacuum, Cryogen-free Field Measurement System for Superconducting Undulator Coils

synchrotron, vacuum, insertion, insertion-device

714

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

The performance of superconducting insertion devices (IDs) depends strongly on the magnetic field quality. Before installing IDs in synchrotron light sources the characterization and precise measurements of their magnetic properties are of fundamental importance. Improvements in magnetic field measurement technology of conventional, i.e. permanent magnet based IDs, made significant progress during the last years and push the capabilities of synchrotron light sources. For superconducting IDs similar major developments are necessary. As a part of our R&D program for superconducting insertion devices we perform quality assessment of their magnetic field properties. This contribution describes details and challenges of the cryostat and measurement setup assembly to perform magnetic measurements of the local field and of the field integrals of superconducting undulator coils in a cold in-vacuum (cryogen free) environment. The focus will be on the outcome of the final acceptance test together with results of first tests performed with mock-up coils.

MOPPP068

Beam Heat Load and Pressure in the Superconducting Undulator Installed at ANKA

electron, vacuum, storage-ring, simulation

717

S. Casalbuoni, S. Gerstl, A.W. Grau, T. Holubek, D. Saez de Jauregui
Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany

A superconducting undulator has been installed in the ANKA (ANgstrom source KArlsruhe) storage ring since March 2005. The beam heat load and pressure on the cold bore were analyzed in the first two years of operation, during which the undulator was operated mainly with open gap. We report here on a larger statistic of beam heat load and pressure data collected in the last years with the undulator operated at different gap positions. The effects of vacuum leaks in the storage ring on the superconducting undulator operation are also described.

MOPPP070

Characterization of Vacuum Chamber Samples for Superconducting Insertion Devices

vacuum, storage-ring, insertion, insertion-device

723

D. Saez de Jauregui, T. Baumbach, S. Casalbuoni, S. Gerstl, A.W. Grau, M. Hagelstein, C. Heske, T. Holubek, B. Krause, A. Seiler, S. Stankov, L. Weinhardt
Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
C.Z. Antoine, Y. Boudigou
CEA/IRFU, Gif-sur-Yvette, France
C. Boffo
BNG, Würzburg, Germany

One of the key components of a superconducting insertion device is the ultra-high vacuum (UHV) chamber. In order to reach the accelerator UHV specifications, it is very important to control the surface chemical content and find proper cleaning procedures. To keep the geometric and resistive wall losses small, it is essential that the top few μm of the surface exhibits low roughness and good electrical conductivity at low temperatures. A 300-μm-thick 316L stainless steel foil, galvanized with a 30-μm copper layer, is used for the next superconducting undulator developed in a collaboration between KIT and BNG. We report here on different spectroscopic analyses as well as on residual resistivity ratio RRR measurements of the copper surface after cleaning procedures and annealing at various temperatures for different periods of time.

MOPPP072

Performance of APPLE-II Type Quasi-Periodic Undulator at HiSOR

radiation, polarization, electron, photon

729

S. Sasaki, M. Arita, K. Goto, A. Miyamoto, T. Okuda
HSRC, Higashi-Hiroshima, Japan

A 1.8-m-long 78-mm-period quasi-periodic APLPE-II undulator was installed in the 700-MeV HiSOR storage ring of Hiroshima Synchrotron Radiation Center. At 23-mm nominal minimum gap, the fundamental photon energies are 3.1 eV, 6.5 eV, and 4.8 eV for horizontal linear, vertical linear, and circular polarization, respectively. The photon energies of observed fundamental and higher harmonic radiations are in good agreement with those of model calculations using measured undulator field and the HiSOR beam parameters. Also, observed flux thorough a slit and a grating monochromator was more than twice larger than that from previously installed 100-mm-period helical undulator for the whole range of radiation spectra. The feedforward COD correction was done to avoid the intensity fluctuation of photon beam in other BM beamlines due to the gap and phase motion of undulator. No fatal effect on the stored electron beam by installing the undulator was observed though a slight beam size change was observed at the minimum gap.

MOPPP074

Magnetic Field Measurement for a THz Undulator Using the Vibrating Wire Method

electron, radiation, laser, resonance

732

S. Kashiwagi, H. Hama, F. Hinode, M. Kawai, X. Li, T. Muto, K. Nanbu, Y. Tanaka
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

Funding: This work is supported by the Ministry of Education, Science, Sports and Culture, Grant-in-Aid for Scientific Research (S), Contract #20226003.
We constructed the undulator that is a basically a Halbach planer type for a generation of intense coherent terahertz radiation from the very short electron bunch. The period length of the undulator and the number of periods are 100 mm and 25, respectively. Its maximum magnetic field is 0.41 T and the K-value is 3.82 with 54 mm gap. The vibrating wire method is studied to measure the periodic magnetic field of the undulator. By measuring amplitudes and phases of standing waves excited on the wire by the Lorentz force between AC current and magnetic field, we can reconstruct the magnetic field distribution along the wire. The theoretical analysis has been performed for the THz undulator and derived a relation between a reproducibility of undulator field and the number of the harmonic mode to use for the reconstruction. A model experiment was demonstrated using 20cm wire and one pair of permanent magnet block. The theoretical study and the results of model experiment using the vibrating wire method will be shown in this conference.

MOPPP075

The Research on Magnetic Properties of Magnet for SSRF Cryogenic Permanent Magnet Undulator

cryogenics, permanent-magnet, radiation, synchrotron

735

Y.Z. He, L. Wang, Q.G. Zhou
SINAP, Shanghai, People's Republic of China

The temperature coefficient of Br and Hci of Nd2Fe14B and Pr2Fe14B permanent magnet are about -0.1 K-1 and -0.6 K-1 respectively, the higher Br and Hci can be obtained at low temperature. By this theory, a cryogenic permanent magnet undulator(CPMU) may be designed, the maximum magnetic field and the Hci of permanent magnet increased 10-50% and 300-500% respectively, compared with the conventional undulators, the higher brightness X-rays and the more resistance to radiation of undulators can be obtained. The Pr2Fe14B permanent magnet has better potential magnetic properties than the Nd2Fe14B permanent magnet at low temperature for having no spin reorientation phenomenon. The permanent magnets are key “heart” magnetic components for cryogenic permanent magnet undulator, since January 2012, the research plan on magnetic properties of domestic permanent magnet for SSRF cryogenic permanent magnet undulator at low temperature by the support of Shanghai and Nation Nature science funds be started, the paper introduced research status of the item.

MOPPP076

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

FEL, 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.

MOPPP077

Heat Load Budget on TPS Undulator in Vacuum

synchrotron, radiation, synchrotron-radiation, vacuum

741

J.C. Huang, J. Chen, C.-S. Hwang, F.-Y. Lin, Y.T. Yu
NSRRC, Hsinchu, Taiwan

The performance of an insertion device is limited by the magnet gap because a small gap affects the dynamic aperture and results in a short life time of the beam. An in-vacuum undulator is designed to have no vacuum chamber between the magnet arrays so to allow the entire magnet gap to be fully used for the dynamic aperture. An in-vacuum undulator can optimally minimize the gap to achieve continuous energy spectra. One problem of an undulator with a small gap is resistive wall heating by the image current. The heat load depends strongly on the injected mode in the storage ring; injection of multiple bunches might deteriorate the thermal performance for the magnet array. In this paper, we present a calculation of the heat load budget for a magnet array of an in-vacuum undulator of Taiwan Photon Source (TPS).

MOPPP078

Status of the First Planar Superconducting Undulator for the Advanced Photon Source

photon, controls, status, radiation

744

Y. Ivanyushenkov, M. Abliz, K.D. Boerste, T.W. Buffington, C.L. Doose, J.D. Fuerst, Q.B. Hasse, M. Kasa, S.H. Kim, R. Kustom, E.R. Moog, D. Skiadopoulos, E. Trakhtenberg, I. Vasserman
ANL, Argonne, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Superconducting technology offers the possibility of building short-period undulators for synchrotron light sources. Such undulators will deliver higher fluxes at higher photon energies to the light source user community. The Advanced Photon Source (APS) team is building the first superconducting planar undulator to be installed in the APS storage ring. The current status of the project is presented in this paper.

MOPPP080

New Concepts for Revolver Undulator Designs

insertion, insertion-device, vacuum, controls

750

B.K. Stillwell, J.H. Grimmer, D.P. Pasholk, E. Trakhtenberg
ANL, Argonne, USA
M.B. Patil
Impact Engineering Solutions, Brookfield, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Dynamic support of revolver undulator magnet structures presents a challenging mechanical problem. Some designs to date employ a support span connected at its ends to the undulator gap separation mechanism. However, this arrangement is problematic for long undulators operating at small gaps since the gap-dependent distortion of the magnet support span scales approximately with the cube of its length and exponentially with reduction in gap. Other designs have been demonstrated that utilize intermediate connections to a central magnet support span, but require additional stiffening members between that span and the magnet arrays. This arrangement is difficult to implement at the APS because of space constraints imposed by existing beam vacuum chambers. We have developed three revolver undulator concepts that provide an extremely rigid magnet support structure, precise rotational positioning, and wide gap tapering ability. Each of the concepts has advantages and disadvantages. All of the concepts are fully compatible with the existing APS-designed gap separation mechanism, which will greatly simplify testing and implementation.

MOPPP085

Single Electron Dynamic of Microwave Undulator

electron, FEL, 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.

MOPPP086

Praseodymium Iron-Boron Undulator With Textured Dysprosium Poles for Compact X-Ray FEL Applications

simulation, cryogenics, insertion, insertion-device

756

R.B. Agustsson, Y.C. Chen, T.J. Grandsaert, A.Y. Murokh
RadiaBeam, Santa Monica, USA
F.H. O'Shea
UCLA, Los Angeles, California, USA
V. Solovyov
BNL, Upton, Long Island, New York, USA

Funding: DOE SBIR #97134S11-I
Radiabeam Technologies is developing a novel ultra-high field short period undulator using two unconventional materials: praseodymium permanent magnets (PrFeB) and textured dysprosium (Tx Dy) ferromagnetic field concentrators. Both materials exhibit extraordinary magnetic properties at cryogenic temperatures, such as very large energy product and record high induction saturation, respectively. The proposed device combines PrFeB and Tx Dy in 3-D hybrid undulator geometry with sub-cm period and up to 3 Tesla pole tip field. Practical realization of these features will significantly surpass state-of-the-art and offer an ideal solution for the next generation of compact X-ray light sources. Initial simulations along with preliminary cryogenic measurements will be presented.

MOPPP088

Control of Nonlinear Dynamics by Active and Passive Methods for the NSLS-II Insertion Devices

polarization, insertion, insertion-device, electron

759

J. Bengtsson, O.V. Chubar, C.A. Kitegi, T. Tanabe
BNL, Upton, Long Island, New York, USA

Funding: US DOE, Contract No. DE-AC02-98CH10886.
Nonlinear dynamics effects from insertion devices (IDs) are known to affect the electron beam quality of third generation synchrotron light sources. In particular, beam lifetime, dynamical aperture and injection efficiency. Methods to model the IDs' non-linear effects are known, e.g. by second-order (in the inverse electron energy) kick maps. Methods to compensate these effects are known as well, e.g. by first-order thin or thick magnetic kicks introduced by "magic fingers," "L-shims," or "current strips." However, due to physical or technological constraints, these corrections are typically only partial. Therefore, a precise model is required for a correct minimization of the residual nonlinear dynamics effects for the combined magnetic fields of the ID and compensating magnets. We outline a systematic approach for such predictions, based on 3D magnetic field and local trajectory calculation in the ID by the Radia code, and particle tracking by Tracy-3. The optimal geometry for the compensating magnets is determined from these simulations using a combination of linear algebra and genetic optimization.

MOPPP089

Development of a PrFeB Cryogenic Undulator at NSLS-II

cryogenics, vacuum, synchrotron, permanent-magnet

762

C.A. Kitegi, P. Cappadoro, O.V. Chubar, T.M. Corwin, H.C. Fernandes, D.A. Harder, P. He, G. Rakowsky, J. Rank, C. Rhein, T. Tanabe
BNL, Upton, Long Island, New York, USA

Recent cryogenic undulators use Praseodymium-Iron-Boron (PrFeB) magnets cooled down to 80K. The main drawn drawback of the PrFeB magnet grades developed so far are their relative low coercive field at ambient temperature, below 2 T which prevents PrFeB based cryogenic undulator from baking. Some precautions are required during the undulator assembling and shimming to ensure ultra high vacuum compatibility. However Hitachi Metal Industry (HMI) recently developed two different grades of PrFeB magnet with large coercive field but at the expense of the remanent field. The magnetization curves have been measured from 40 K up to 400 K to determine the field increase and to investigate the magnet withstanding to baking. An IVU prototype has also been baked. Magnetic measurements before and after baking are also presented.

MOPPP090

Spectral Performance of Segmented Adaptive-Gap In-Vacuum Undulators for Storage Rings

electron, vacuum, photon, radiation

765

O.V. Chubar, J. Bengtsson, A. Blednykh, C.A. Kitegi, G. Rakowsky, T. Tanabe
BNL, Upton, Long Island, New York, USA
J.A. Clarke
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: US DOE, Contract No. DE-AC02-98CH10886.
We propose an approach to the optimization of segmented in-vacuum undulators, in which different segments along an undulator may have different gaps and periods. This enables close matching between the gaps and the vertical "envelope" of electron beam motion in a storage ring straight section (carefully satisfying the associated vertical "stay clear" constraint) and, at the same time, precise tuning of all the segments to the same fundamental photon energy. Thanks to this, the vertical gaps in segments located closer to straight section center can be smaller than at extremities, and so the entire undulator structure can offer better magnetic performance, compared to the case of a standard undulator with constant gap (and period) over its length. We will present magnetic field, radiation flux, brightness and intensity calculation results for such segmented adaptive-gap in-vacuum undulators and demonstrate their gain in spectral performance over standard in-vacuum undulators, both for room-temperature and cryo-cooled realizations.

MOPPP091

Recent Developments at the DELTA THz Beamline

laser, electron, radiation, storage-ring

768

P. Ungelenk, M. Bakr, H. Huck, M. Höner, S. Khan, R. Molo, A. Nowaczyk, A. Schick, M. Zeinalzadeh
DELTA, Dortmund, Germany

Funding: Work supported by DFG, BMBF, and by the Federal State NRW.
During 2011, a new dedicated THz beamline has been constructed and commissioned at DELTA, a 1.5 GeV synchrotron light source operated by the TU Dortmund University. This beamline enables extracting and detecting coherent THz pulses caused by a laser-induced density modulation of the electron bunches. Ongoing experiments aim at characterizing the THz radiation as well as investigating the evolution of the density modulation over subsequent revolutions following the initial laser-electron interaction in an undulator.

MOPPR050

Design and Analysis of EPU XBPM in TPS

photon, synchrotron, synchrotron-radiation, radiation

894

A. Sheng, C.M. Cheng, C.K. Kuan
NSRRC, Hsinchu, Taiwan
D. Shu
ANL, Argonne, USA

Several planer and elliptical polarized undulators (EPU) beam lines have been proposed and are to be built for Taiwan Photon Source (TPS) in National Synchrotron Research Center (NSRRC). Due to its complexity, with changing of vertical as well as horizontal deflection parameters (Kx and Ky), one finds that regular diamond bladed photon beam position monitor (XBPM) would not be sufficient to detect the center location of the undulator. A new conceptual design of EPU XBPM has been analyzed both in thermal as well as photon aspects. A prototype by taking advantage of fluorescent some of the diamond detectors has been designed and implemented in Taiwan Light Source (TLS) for testing. Some analysis and design scenarios are presented in this paper.

TUEPPB013

Development of an Advanced Computational Tool for Start-to-End Modeling of Next Generation Light Sources

electron, radiation, simulation, wakefield

1143

J. Qiang, J.N. Corlett, C.E. Mitchell, C. F. Papadopoulos, G. Penn, R.D. Ryne, M. Venturini
LBNL, Berkeley, California, USA

Funding: Work supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Start-to-end simulation plays an important role in designing next generation light sources. In this paper, we present recent progress in further development and application of the parallel beam dynamics code, IMPACT, towards the fully start-to-end, multi-physics simulation of a next generation X-ray FEL light source. We will discuss numerical methods and physical models used in the simulation. We will also present some preliminary simulation results of a beam transporting through photoinjector, beam delivery system, and FEL beamlines.

TUEPPB015

Generation of Narrow-Band Coherent Tunable Terahertz Radiation using a Laser-Modulated Electron Beam

laser, electron, radiation, bunching

1146

M.P. Dunning, C. Hast, E. Hemsing, R.K. Jobe, D.J. McCormick, J. Nelson, T.O. Raubenheimer, K. Soong, Z.M. Szalata, D.R. Walz, S.P. Weathersby, D. Xiang
SLAC, Menlo Park, California, USA

Funding: Work supported by US DOE contract DE-AC02-76SF00515.
The technical layout and initial results of an experiment to generate narrow-band, coherent, tunable terahertz (THz) radiation through the down-conversion of the frequency of optical lasers using a laser-modulated electron beam are described. In this experiment a 120 MeV electron beam is first energy modulated by two lasers with different wavelengths. After passing through a dispersive section, the energy modulation is converted into a density modulation at THz frequencies. This density-modulated beam will be used to generate narrow-band THz radiation using a coherent transition radiator inserted into the beam path. The central frequency of the THz radiation can be tuned by varying the wavelength of one of the two lasers or the energy chirp of the electron beam. The experiment is being performed at the NLCTA at SLAC, and will utilize the existing Echo-7 beamline, where echo-enabled harmonic generation (EEHG) was recently demonstrated.

TUPPC025

Solaris Storage Ring Lattice Optimization with Strong Insertion Devices

lattice, optics, insertion, storage-ring

1218

A.I. Wawrzyniak, C.J. Bocchetta
Solaris, Kraków, Poland
M. Eriksson, S.C. Leemann
MAX-lab, Lund, Sweden

Funding: Work supported by the European Regional Development Fund within the frame of the Innovative Economy Operational Program: POIG.02.01.00-12-213/09
The Solaris synchrotron light facility under construction in Kraków will be a replica of the 1.5 GeV storage ring of MAX IV. This compact 3rd generation light source has been designed to have an emittance of 6 nmrad and operate with 500 mA stored current for VUV and soft X-Rays production. The lattice design consists of 12 Double Bend Achromats (DBA) with each DBA cell integrated into one solid iron block. Twelve 3.5 m long straight sections are available of which 10 will be equipped in various insertion devices. These devices will differ from those adopted by MAX IV. For X-ray production one or more superconducting wigglers will be used, while APPLE II type undulators will be used for variable polarised light production. The linear and nonlinear lattice dynamics have been studied with these perturbing insertion devices included in the ring and results are presented in this paper.

TUPPC075

Study of Nonlinear Beam Dynamics Effects for DEPU at SSRF

polarization, electron, photon, focusing

1347

M. Zhang, Q.G. Zhou
SINAP, Shanghai, People's Republic of China

A pair of EPUs (DEPU) with the period 58mm and 148mm, covering the energy ranges from 20 to 200eV and 200 to 2000eV of arbitrary polarized light, will be developed for the SSRF soft X-ray beam line for ARPES and PEEM. The effects of DEPU to tune-shift produced by the nonlinear beam dynamics are studied and the results are presented in this paper. The corresponding magnet field shimming technology to reduce these effects is also investigated.

TUPPD036

Novel Designs for Undulator Based Positron Sources

positron, target, photon, damping

1485

M. Jenkins
Cockcroft Institute, Warrington, Cheshire, United Kingdom
I.R. Bailey, M. Jenkins
Lancaster University, Lancaster, United Kingdom

At least three proposed future colliders(ILC, CLiC and LHeC) require a positron source with a yield greater than 10¹⁴ e+/s. An undulator based positron source has the potential to provide the required yield. This design generates gamma rays by using a high energy electron beam traveling through a superconducting helical undulator. The gamma rays then pair produce in a titanium alloy target to produce positrons. This is the ILC baseline positron source. Two drawbacks to the undulator-based positron source are that it couples the positron source to the electron beam operation and that it exhibits a low conversion efficiency of photons to positrons. A self-seeding undulator-based positron source has been proposed. This starts with a low intensity positron beam which travels through the undulator to produce more positrons which are recirculated through the source to increase the intensity until the design yield is achieved. Multiple targets have been added to increase the conversion efficiency of the positron source. In this study I present simulation results for such a design and consider the feasibility of this design at the ILC, CLiC or LHeC.

TUPPP005

LUNEX5: A French FEL Test Facility Light Source Proposal

FEL, laser, emittance, electron

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.

TUPPP007

Modifications to the Machine Optics of BESSY II Necessitated by the EMIL Project

optics, cryogenics, dipole, storage-ring

1614

P.O. Schmid, J. Bahrdt, T. Birke, R. Follath, P. Kuske, D. Simmering, G. Wüstefeld
HZB, Berlin, Germany

The Helmholtz Zentrum Berlin and the Max Planck Society are going to build a new dedicated X-ray beam line at the synchrotron source light source BESSY II which will be used for analyzing materials for renewable energy generation. The new large scale project has been dubbed EMIL. In this document we present the modifications to the machine optics and to what extent these changes affect the performance of BESSY II.

TUPPP008

Recent Results From the Short-Pulse Facility at the DELTA Storage Ring

laser, radiation, electron, synchrotron

1617

A. Schick, M. Bakr, H. Huck, M. Höner, S. Khan, R. Molo, A. Nowaczyk, P. Ungelenk, M. Zeinalzadeh
DELTA, Dortmund, Germany

Funding: Work supported by DFG, BMBF and by the Federal State NRW.
At the 1.5 GeV synchrotron light source DELTA, operated by the TU Dortmund University, a new facility for ultrashort pulses in the VUV and THz regime is currently under commissioning. Here, the interaction of an intense, ultrashort laser pulse, co-propagating with the electrons in an optical klystron, leads to coherent synchrotron radiation at harmonics of the incident laser wavelength. The aim of the present commissioning steps is to extend the emitted wavelength down to about 50 nm, enabling femtosecond-resolved pump-probe experiments in the VUV regime. Other issues include increasing the photon flux by optimizing the laser-electron interaction and improving the stability and ease of operation of the source.

TUPPP009

Status of the PETRA III Upgrade

shielding, radiation, vacuum, site

1620

M. Bieler, K. Balewski, W. Drube, J. Keil, A. Kling
DESY, Hamburg, Germany

Since 2010 PETRA III, a third generation light source at DESY, has been running as a user facility, with all 14 undulator beam lines operational since autumn 2011. In order to fulfill the request for more beam time after the shut down of DORIS at the end of 2012, it was decided to add two additional halls at PETRA III, each housing 5 additional beam lines. Next to these two new halls about 100 m of the accelerator will be completely remodeled to install additional undulators. The upgrade should be accomplished during a 6 month shut down in 2013. In order to minimize this down time, it was decided to keep the existing accelerator tunnel in place. This has impact both on the mechanical connection between the accelerator and the experimental floor and on the design of the optical beam lines in the tunnel. In this paper the layout of the upgraded accelerator will be shown. The design status of the major components for the upgrade will be presented.

TUPPP016

Recent Development of PF Ring and PF-AR

injection, polarization, linac, vacuum

1641

Y. Tanimoto, T. Aoto, S. Asaoka, K. Endo, K. Haga, K. Harada, T. Honda, Y. Honda, M. Izawa, Y. Kobayashi, A. Mishina, T. Miyajima, H. Miyauchi, S. Nagahashi, N. Nakamura, T. Nogami, T. Obina, T. Ozaki, C.O. Pak, H. Sakai, S. Sakanaka, H. Sasaki, Y. Sato, K. Satoh, M. Shimada, K. Shinoe, T. Shioya, M. Tadano, T. Tahara, T. Takahashi, R. Takai, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, M. Yamamoto
KEK, Ibaraki, Japan
H. Takaki
ISSP/SRL, Chiba, Japan

After the earthquake of March 11, two light sources of KEK, PF ring and PF-AR, have recovered the regular operation from October, 2011. We installed tandem variably-polarized undulators at PF ring in 2009. Recently, the orbit switching system has been completed with sufficient feed-forward orbit compensation at 10-Hz. PF ring is usually operated at 450 mA with a top-up injection using the pulsed sextupole magnet instead of the conventional kicker magnets. The transverse and longitudinal instabilities are suppressed by a digital feedback system using the iGp signal processor. In the longitudinal direction, we observed unstable quadrupole mode oscillation which could not be controlled by the feedback system. We had applied the phase modulation of the main RF cavity to stabilize the quadrupole oscillation before. Old-type RF-shielded gate valves damaged by the earthquake were removed from the ring during the summer maintenance. In the operation after autumn, the quadrupole oscillation can be cured by dividing the bunch train of partial-filling. Without the phase modulation, the effective brightness of SR beam has been improved especially at beam lines of finite dispersion function.

TUPPP021

Orbit Stability at ALBA

insertion, insertion-device, wiggler, booster

1653

M. Muñoz, G. Benedetti, D. Einfeld, J. Marcos, Z. Martí
CELLS-ALBA Synchrotron, Cerdanyola del Vallès, Spain

The synchrotron light source ALBA is in the final stage of the Storage Ring commissioning, with the beamline commissioning well under way. In the month of beam line commissioning, the storage ring has provided an stable beam, with horizontal and vertical stabilities better than the micrometer in both planes in DC and a good reproducibility of the beam position day by day. In this paper we review the performance of the Slow Orbit Feedback, the changes in orbit due to insertion devices, as well as the first measurement using the 10 kHz sampling mode of the Libera BPMs, together with the status of the implementation of the Fast Orbit Feedback system.

TUPPP032

Use of Multi-objective Methods for Choosing Undulators for Storage Rings

brightness, photon, target, storage-ring

1680

M. Borland
ANL, Argonne, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Users of storage ring light sources generally rely on undulators to provide the highest brightness. Choice of the optimal undulator period is complicated by the fact that users do not operate at a single photon energy or place equal weight on operation at all photon energies of interest. In addition, some users may be best served by a double- or triple-period revolver device. In this paper, we present a method of narrowing the choice of undulator periods based on multi-objective techniques. Applications are shown in the context of the Advanced Photon Source Upgrade.

TUPPP038

Electron Beam Collimation for the Next Generation Light Source

collimation, gun, linac, impedance

1695

C. Steier, P. Emma, H. Nishimura, C. F. Papadopoulos, F. Sannibale
LBNL, Berkeley, California, USA

Funding: Work supported by the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Next Generation Light Source will deliver high (MHz) repetition rate electron beams to an array of free electron lasers. Because of the significant average current in such a facility, effective beam collimation is extremely important to minimize radiation damage to undulators, prevent quenches of superconducting cavities, limit dose rates outside of the accelerator tunnel and prevent equipment damage. This paper describes the conceptual design of the collimator system, as well as the results of simulations to test its effectiveness.

TUPPP045

Creation of FELWI using Large Amplification Regime

electron, FEL, 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

vacuum, FEL, 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

FEL, laser, electron, bunching

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

FEL, electron, photon, laser

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.

TUPPP056

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

FEL, electron, radiation, laser

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

FEL, laser, radiation, simulation

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

FEL, cavity, radiation, 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

linac, gun, electron, FEL

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.

TUPPP066

CLARA - A Proposed New FEL Test Facility for the UK

FEL, electron, laser, 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.

TUPPP067

Collimation System Design and Performance for the SwissFEL

collimation, linac, wakefield, electron

1753

F. Jackson, J.-L. Fernández-Hernando
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
D. Angal-Kalinin
Cockcroft Institute, Warrington, Cheshire, United Kingdom
H.-H. Braun, S. Reiche
Paul Scherrer Institut, Villigen, Switzerland

Electron beam collimation in the SwissFEL is required for protection of the undulators against radiation damage and demagnetization. The design for the SwissFEL collimation for the hard X-ray undulator (Aramis) includes transverse collimation in the final accelerating linac sections, plus an energy collimator in a post-linac chicane. The collimation system must provide efficient protection of the undulator for various machine modes providing varied final beam energy to the undulator. The performance of the transverse and energy collimation design is studied in simulations including evaluation of the transverse collimation for various beam energies and the effect of grazing particles on the energy collimator. Collimator wakefields are also considered.

TUPPP069

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

quadrupole, FEL, 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).

TUPPP073

Machine Parameter Studies for an FEL Facility Using STAFF

FEL, photon, 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.

TUPPP079

Design Alternatives for a Free Electron Laser Facility

FEL, linac, 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

FEL, 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

radiation, FEL, 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, FEL, 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.

TUPPP087

Commissioning of the Fritz Haber Institute Mid-IR FEL

FEL, wiggler, electron, linac

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.

TUPPR002

Simulations of Positron Polarization in the Undulator-Based Source

positron, polarization, electron, photon

1810

A. Ushakov, O.S. Adeyemi, V.S. Kovalenko, L.I. Malysheva, G.A. Moortgat-Pick
University of Hamburg, Hamburg, Germany
A.F. Hartin
DESY, Hamburg, Germany
S. Riemann, F. Staufenbiel
DESY Zeuthen, Zeuthen, Germany

Funding: This work is supported by the German Federal Ministry of Education and Research, Joint Research Project R&D Accelerator "Spin Management", contract number 05H10GUE
The generation of an intense and highly polarized positron beam is a challenge. The design for the International Linear Collider proposes a positron source based on a helical undulator located at the end of the electron linac. This design allows us to utilize a high energy linear accelerator with both electron and positron beams polarized. The polarization of the positron beam can be enhanced using a photon collimator. The optimization of positron yield and polarization for a wide energy range has been studied for different undulator parameters and collimator designs, taking into account realistic parameters for the capture section. In particular, the effects of misalignment and tolerances are considered.

TUPPR040

Update on ILC Positron Source Study at ANL

positron, polarization, photon, electron

1906

W. Liu, W. Gai
ANL, Argonne, USA

As the new ILC baseline has moved the positron production to the end of electron main linac, both the drive beam energy and beamline layouts have also been changed for the positron source. Now the drive beam energy will be varying from 150GeV to 250GeV and 500GeV (for TeV upgrade) as the colliding center of mass (CM) energy changes. Systematic studies on the performance of positron source under different running scenarios have been done at ANL and the results are presented in this paper.

TUPPR041

Update on ILC Positron Source Start-to-End Simulation

positron, electron, lattice, linac

1909

W. Liu, W. Gai
ANL, Argonne, USA

As a result of the changes in the new ILC base line, there are many changes in the positron source beamline layouts and thus a new lattice design is required. According to the changes in the ILC baseline, a new lattice design for the ILC positron source has been developed at ANL. In this paper, both the new ILC positron source beamline lattice and the corresponding start to end simulation results are presented.

TUPPR042

On the Polarization Upgrade of ILC Undulator-based Positron Source

polarization, positron, photon, electron

1912

W. Liu, W. Gai
ANL, Argonne, USA
S. Riemann
DESY, Hamburg, Germany
A. Ushakov
University of Hamburg, Hamburg, Germany

The current nominal polarization for ILC undulator based positron source is 30% without photon collimators. In order to improve the effective luminosity, an upgrade of positron source with higher polarization is required. Some studies on the upgrade options have been done at both DESY and ANL, and the results are presented in this paper.

WEYB01

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

laser, electron, emittance, FEL

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]

WEOBB03

Computation of the Wigner Distribution for Undulator Radiation

radiation, electron, synchrotron, brightness

2149

I.V. Bazarov, A.D. Gasbarro
CLASSE, Ithaca, New York, USA

In the effort to optimize brightness in synchrotron radiation sources, questions arise as to the most desirable electron beam parameters given a particular insertion device. With a detailed understanding of the distribution of emitted photons, the electron beam profile can be effectively matched. We have developed tools which, by way of the Wigner distribution, compute the phase space of photons radiated by an electron bunch. An explanation is provided of the workings of the code itself with mention of important algorithms that have been implemented. We demonstrate via numerical examples the Wigner distributions of the undulator radiation. In particular, it is shown that the phase space of light differs appreciably from the Gaussian distribution assumed in many analytical expressions and, therefore, the more thorough approaches should be used for computation of related quantities.

Slides WEOBB03 [2.555 MB]

WEEPPB006

LCLS Femto-second Timing and Synchronization System Update

laser, controls, LLRF, EPICS

2176

G. Huang, J.M. Byrd, R.B. Wilcox
LBNL, Berkeley, California, USA
A.R. Fry, B.L. Hill
SLAC, Menlo Park, California, USA

Femto second timing and synchronization system has been installed on LCLS operation for 2 years. The requirement of more receiver at different location of the experimental hall urge us to develop a new version of receiver chassis and sync-head. Two sets of the new receiver chassis has been installed to the SXR and CXI end station. To help end user the diagnose the system, a intermediate GUI is developed to show some diagnostic information.

WEPPC005

Parts Management during Fabrication at the European XFEL

controls, cavity, cryomodule, niobium

2212

L. Hagge, J.A. Dammann, S. Eucker, A. Herz, J. Kreutzkamp, D. Käfer, D. Szepielak, N. Welle
DESY, Hamburg, Germany

This presentation describes policies and methods for parts management during fabrication at the European XFEL. The objective is to provide procedures for reliably gathering, recording, processing and archiving the complete mandatory fabrication information. The solution is a foundation for conducting Quality Assurance and Quality Control (QA/QC), as it ensures that acceptance tests are recorded, signed-off and followed-up in a reliable and orderly way. It achieves compliance with legal regulations in certain areas. One example is the pressurized equipment directive (PED), which for certain (parts of) equipment requires that the complete fabrication and usage history is tracked throughout the entire lifespan of the XFEL facility. In addition, the solution provides a basis for building the necessary documentation for later installation, operation and maintenance activities. The solution is established in the series production of several accelerator components. It uses DESY’s Engineering Data Management System as central collaboration and documentation platform.

WEPPD008

Recondenser Performance: Impact on the Superconducting Undulator Magnet at Argonne National Laboratory

ion, cryogenics, background, factory

2513

J.M. Pfotenhauer, D.M. Schick
UW-Madison/EP, Madison, Wisconsin, USA

Funding: This work is supported by Argonne National Laboratory, subcontract number 9F-31982.
The current sharing temperature of 6.5 K for the superconducting undulator magnet being developed at Argonne National Laboratory drives the thermal design of the magnet’s cooling system. In order to remain below the current sharing temperature, a thermo-siphon cooling loop is being developed to sweep the anticipated heat load away from the magnet windings and deposit it in the associated liquid helium reservoir located above the magnet. Performance of the magnet’s cooling system is crucially dependent on the ability of the re-condenser to maintain the reservoir’s saturation temperature near 4 K, despite thermal stratification and slowly varying thermal profiles within the vapor region above the liquid in the reservoir. Here we report the results of an experimental investigation of the impact of various geometric configurations for the re-condenser and the thermal resistance associated with the film layer at the re-condensing surface, on the time-varying saturation temperature within the helium reservoir. The resulting temporal thermal variations in the superconducting winding are highlighted as well as the impact they have on the magnet’s stability.

WEPPD032

Heat Load Studies in Target and Collimator Materials for the ILC Positron Source

photon, positron, polarization, target

2576

F. Staufenbiel, S. Riemann
DESY Zeuthen, Zeuthen, Germany
O.S. Adeyemi, V.S. Kovalenko, L.I. Malysheva, G.A. Moortgat-Pick, A. Ushakov
University of Hamburg, Hamburg, Germany

An intense polarized positron beam for future linear colliders can be produced using a high power beam of circularly polarized photons which penetrates a thin titanium-alloy target. The degree of polarization can be increased by cutting the outer part of the photon beam generated in a helical undulator using a collimator in front of the target. However, the photon beam induces substantial heat load and stress inside the target and collimator materials. In order to avoid failure of these components the stress evolution has been simulated. The results as well as the corresponding material arrangements for the photon collimator design are presented.

WEPPD052

Compression and Synchronization of MeV Scale Subpicosecond Electron Beams in a THz IFEL Interaction

electron, laser, simulation, space-charge

2636

J.T. Moody, R.K. Li, P. Musumeci, C.M. Scoby, H.L. To
UCLA, Los Angeles, California, USA

Recent development of MW peak power THz sources from efficient optical rectification of broadband IR pulses by pulse front tilting has made available laser locked single cycle THz pulses suitable for compression and laser-synchronization of photoinjector generated subpicosecond electron beams. Three dimensional simulations have shown that a waveguided 8 pulse THz train can be used to interact with a sub picoseconds electron beam in an undulator to achieve compression and laser synchronization. We present a THz pulse train source currently under development at UCLA PBPL as well as detailed 3 dimensional simulations including the effect of the interaction on transverse beam quality.
DOE-BES No. DE-FG02-92ER40693 and DOE-BES No. DE-FG02-07ER46272

WEPPD053

The LLNL/UCLA High Gradient Inverse Free Electron Laser Accelerator

electron, laser, acceleration, simulation

2639

J.T. Moody, P. Musumeci
UCLA, Los Angeles, California, USA
G.G. Anderson, S.G. Anderson, M. Betts, S.E. Fisher, D.J. Gibson, A.M. Tremaine, S.S.Q. Wu
LLNL, Livermore, California, USA

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
We describe the Inverse Free Electron Accelerator currently under construction at Lawrence Livermore National Lab. Upon completion of this accelerator, high brightness electrons generated in the photoinjector blowout regime and accelerated to 50 MeV by S-band accelerating sections will interact with > 4 TW peak power Ti:Sapphire laser in a highly tapered 50 cm undulator and experience an acceleration gradient of >200 MeV/m. We present the final design of the accelerator as well as the results of start to end simulations investigating preservation of beam quality and tolerances involved with this accelerator.

WEPPP032

Inverse Free Electron Laser Acceleration Using Ultra-fast Solid State Laser Technology

laser, simulation, acceleration, electron

2795

S.G. Anderson, G.G. Anderson, S.M. Betts, S.E. Fisher, D.J. Gibson, A.M. Tremaine, S.S.Q. Wu
LLNL, Livermore, California, USA
J.T. Moody, P. Musumeci
UCLA, Los Angeles, California, USA

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
We present a theoretical and computational study of the application of Ti:Sapphire laser technology to Inverse Free Electron Laser (IFEL) accelerators. Specifically, the regime in which the number of undulator periods is comparable to the number of cycles in the laser pulse is investigated and modifications to the IFEL accelerator equations and laser requirements are given. 1-D and 3-D simulations are used to study the IFEL interaction in this regime. In addition, the effects of non-Gaussian laser pulses, and astigmatic aberrations in the laser focus are analyzed. Finally, the tools developed for this study are applied to the LLNL/UCLA IFEL experiment, and potential future IFEL designs.

WEPPP036

Undulator Commissioning for a High-Energy-Gain Inverse Free Electron Laser Experiment

laser, electron, simulation, acceleration

2804

J.P. Duris, R.K. Li, P. Musumeci, E.W. Threlkeld
UCLA, Los Angeles, California, USA

Funding: This work was supported by DOE grant DE-FG02-92ER40693 and Defense of Threat Reduction Agency award HDTRA1-10^-1-0073.
We present the construction and measurement details of a strongly tapered helical undulator for the Rubicon Inverse Free Electron Laser (IFEL) experiment. Results of the magnetic field measurements are presented, and these are used to produce simulations of the expected performance of the experiment. Finally, a study of the tolerances on the input parameters of the experiment is presented.

WEPPR082

The Collective Effects of Long Straight Sections (LSSs) in the Advanced Photon Source Upgrade

impedance, storage-ring, collective-effects, injection

3120

Y.-C. Chae, L.H. Morrison
ANL, Argonne, USA

Funding: Work supported by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06CH11357.
The Advanced Photon Source is a 7-GeV hard x-ray synchrotron light source. The APS Upgrade specifies additional beamlines delivering higher brightness and flux as well as for the short-pulse x-ray (SPX). In order to fulfill these demands we plan to provide long straight sections (LSS), for which the total length of the insertion devices is increased to 7.7m. The long straight section also helps in implementing the SPX scheme without removing insertion devices. However, the impedance of the LSS may reduce the single-bunch current of 16 mA per bunch delivered to the users during hybrid fill. We estimate the effect of LSS impedance on the bunched beam current and propose an impedance optimization of the undulator chamber with a small gap.

WEPPR086

Computed Wake Field Effects from Measured Surface Roughness in the Walls of the Cornell ERL

wakefield, vacuum, scattering, impedance

3132

M.G. Billing, G.H. Hoffstaetter, C.E. Mayes, K.W. Smolenski, H.A. Williams
CLASSE, Ithaca, New York, USA

Funding: Work supported by the NSF ERL Phase 1B Cooperative Agreement (DMR-0807731)
Wake fields arise from the discontinuities in a smooth vacuum chamber and will cause energy spread in the passing bunch. In an energy recovery linac (ERL), the spent bunches are decelerated before they are dumped to reuse the beam’s energy for the acceleration of new bunches. While the energy spread accumulated from wakes before deceleration is small compared to the beam’s energy after full acceleration, it becomes more important relatively as the beam’s energy decreases.* Thus, in an ERL wake fields can produce very significant energy spread in the beam as it is decelerated to the energy of the beam dump. We report on calculations of wake fields due to the roughness of the surface of the vacuum chamber walls as it affects the Cornell ERL design. These calculations include the effects from the measured roughness for real vacuum chamber wall surfaces.
* M. Billing, “Effect of Wake Fields in an Energy Recovery Linac”, PAC’09, Vancouver, BC, Canada, 4-8 May 2009.

WEPPR098

Two Dimensional Impedance Analysis of Segmented IVU

impedance, vacuum, simulation, storage-ring

3168

A. Blednykh, G. Bassi, J. Bengtsson, O.V. Chubar, C.A. Kitegi, T. Tanabe
BNL, Upton, Long Island, New York, USA

Funding: Work supported by DOE contract No: DE-AC02-98CH10886
Segmented Adaptive-Gap In-Vacuum Undulator (IVU) with variable magnetic gap along z-axis is considered as an alternative to the Constant Gap IVU (7mm gap) for the NSLS-II storage ring. The length of the Constant Gap IVU for a given minimum gap is limited by the beam stay clear aperture. With the new conceptual design of IVU the magnetic gap can be varied along z-axis and its minimum gap can be reduced down to 5.25mm in the center of the structure for the same stay clear aperture. Beam impedance becomes an important issue since the new design consists of several magnet gaps. Wakepotentials and impedances have been analyzed for a new type of IVU and the results compared with data for the reference geometry which is the Constant Gap IVU.

THPPD008

Status of the PAL-XFEL Undulator System

controls, FEL, 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.

THPPR002

The Undulator Control System for the European XFEL

controls, photon, quadrupole, electron

3966

S. Karabekyan, A. Beckmann, J. Pflüger
European XFEL GmbH, Hamburg, Germany
N. Burandt, J. Kuhn
Beckhoff Automation GmbH, Verl, Germany
A. Schöps
DESY, Hamburg, Germany

The European XFEL project is a 4th generation light source. The first beam will be delivered in the beginning of 2015 and will produce spatially coherent ≤80fs short photon pulses with a peak brilliance of 10³²–10³⁴ photons/s/mm²/mrad²/0.1% BW in the energy range from 0.26 to 29 keV at electron beam energies of 10.5 GeV, 14 GeV, or 17.5 GeV . The Undulator systems are used to produce photon beams for SASE 1, SASE 2 and SASE 3. Each undulator system consists of an array of undulator cells installed in a row along the electron beam. A single undulator cell itself consists of a planar undulator, a phase shifter, magnetic field correction coils and a quadrupole mover. This paper describes the design of the entire undulator control system including local and global control. It presents a concept of integration of the undulator control into the accelerator control system as well as into the experiment control.

THPPR033

Tests and Measurements with the Embedded Radiation-monitor-system Prototype for Dosimetry at the European XFEL

radiation, linac, electron, neutron

4041

F. Schmidt-Föhre, D. Nölle, R. Susen, K. Wittenburg
DESY, Hamburg, Germany

A new Embedded Radiation-Monitor-System is currently under development for use in the upcoming European XFEL, that is being built at a length of approx. 3.4 km between the campus of the Deutsches Elektronen-Synchrotron DESY at Hamburg and Schenefeld at Schleswig-Holstein. Most of the electronic systems cabinets for machine control, diagnostics and safety of the XFEL will be located inside the accelerator tunnel. To prevent significant radiation damage at electronic systems in certain sections of the XFEL, all electronic cabinets inside the tunnel will be sufficiently shielded according to pre-estimated radiation levels. In addition, accumulated dose inside these electronic cabinets and in undulator regions will be monitored for the impact of Gamma- and Neutron-radiation by a new radiation monitor system. Life cycle estimations for these electronics and the undulators will provide safety limits for correct function and in time part exchange due to radiation, before significant radiation damage occurs. A prototype of the Gamma radiation-monitor system section has been successfully designed and tested at the DESY Linac II. Prototype tests and according measurements will be presented.

FRXAB01

Symplectic Tracking and Compensation of Dynamic Field Integrals in Complex Undulator Structures

permanent-magnet, simulation, polarization, dipole

4165

J. Bahrdt, G. Wüstefeld
HZB, Berlin, Germany

This presentation covers analytical models that describe the interaction of an electron beam with the magnetic field of undulators. Analytic approximations to the Hamilton-Jacobi equation yield generating functions useful for particle tracking and therefore efficient simulation. Analytic expressions for kick maps of APPLE II undulators are presented as well. Passive and active shimming schemes including magic fingers and current sheets are also modeled. Applications at BESSY II are discussed which ensure efficient injection during top-up to satisfy machine protection and radiation safety requirements.

Slides FRXAB01 [1.922 MB]

FRYAP01

The Future of X-ray FELs

FEL, 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]