Workshop On Ultrafast Electron Sources For Diffraction And .

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012H. Panuganti (Northern Illinois University)8. Development of Hybrid Gun for the High Brightness Beam GenerationA. Fukasawa, S. K. Mahapatra, H. To, B. Baumgartner, J. B. Rosenzweig, P. Musumeci, R.Li, UCLA, CA, USADavid Alesini, Luca Ficcadenti, Bruno Spataro, INFN/LNF, Frascati, ItalyA. Valloni, Luigi Palumbo, Rome University La Sapienza, Rome, Italy9. Dispersion Compensation for Attosecond Electron PulsesM. Centurion (University of Nebraska – Lincoln)10. High Brightness Sub-picosecond Electron Pulse GenerationJ. Li (East China Normal University, State Key Laboratory of Precision Spectroscopy)11. Multi-Objective Molecular Dynamics Simulations with the GPT CodeB. van der Geer (Pulsar Physics)12. Time Resolved Electron Diffraction on NanomaterialsP. Zhou (Faculty of Physics, University of Duisburg-Essen)13. Ultracold and Ultrafast Electrons Diffracted from GrapheneE. Vredenbregt (Eindhoven University of Technology)14. Ultrafast Time Resolved Surface Sensitive Electron Diffraction with Tilted Pump PulseFrontsC. Streubühr (Faculty of Physics, University of Duisburg-Essen)10

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012Scientific Opportunities with Ultrafast Electron Diffraction andMicroscopyPresenter: J. Cao (Florida State Univ.)In the past ten years, we have witnessed rapid advancement of ultrafast electrondiffraction and microscopy. In many cases, these techniques have demonstratedthe unprecedented capability of directly probing the dynamical processes at therelevant atomic time and length scales, thus providing new scientificopportunities in the fields of biology, chemistry, physics, and materials science.This talk will highlight some of these recent development and applications as wellas some future perspectives.11

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012State of Art of Electron Microscopy and Future challengesPresenter: L. Fitting Kourkoutis (Cornell University)L. Fitting Kourkoutis, J. A. Mundy, D. A. Muller*School of Applied and Engineering Physics, Cornell University, Ithaca, NY14853*Kavli Institute at Cornell for Nanoscale ScienceAtomic-resolution spectroscopic imaging in state-of-the-art electronmicroscopes is now capable of unraveling bonding details at buriedinterfaces and clusters, providing both physical and electronic structureinformation [1]. The thousand-fold increase in electron energy lossspectroscopy (EELS) mapping speeds over conventional microscopes allowsus to collect data from millions of spectra. In complex electronic materialsinterfaces and defects can dramatically change the macroscopic propertiesof the system. Using spectroscopic imaging microscopic inhomogeneities,atomic-scale interdiffusion and bonding changes can now readily becharacterized and correlated with the macroscopic properties of thestructure [2].[1] D. A. Muller, L. F. Kourkoutis, M. Murfitt, J. H. Song, H. Y. Hwang, J.Silcox, N. Dellby, O. L. Krivanek, Science 319, 1073 (2008).[2] L. F. Kourkoutis, J. H. Song, H. Y. Hwang, D. A. Muller, Proc. Natl. Acad.Sci. 107, 11682 (2010).12

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012Femtosecond Electron Diffraction: Heralding the Era ofAtomically-Resolved DynamicsPresenter: G. Sciaini (DESY and University of Hamburg)One of the great dream experiments in Science is to directly observe atomicmotions as they occur. Femtosecond electron diffraction provided the first ‘light’of sufficient intensity to achieve this goal by attaining atomic resolution tostructural changes on the relevant timescales. During my talk I will cover thetechnical progress that made this new level of acuity possible and give a survey ofthe new insights gained from an atomic level perspective of structural dynamics1.Thermally and purely electronically driven atomic displacements are going to bediscussed as well as phenomena involving strongly correlated charge densitywave systems. I will finalize my talk showing recent results obtained for anorganic crystal composed by light scattering centers. Here, we implemented arecently developed ultra-bright femtosecond electron source to obtain anatomically-resolved map of the relevant molecular motions driving the photoinduced insulator-to-metal phase transition in the organic charge-transfer salt(EDO-TTF)2PF6. This study is the first in its kind and illustrates the potential ofultra-bright femtosecond electron sources to provide new insights into complexdynamical phenomena relevant to chemistry and biology.13

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012MeV UED and Its Applications for Correlated Material StudiesPresenter: P. Zhu (BNL and Shanghai Jiaotong University)MeV electron diffraction with a 100-fs time resolution and 5-fC single-shotimaging sensitivity has been experimentally demonstrated. The MeV-UED hasbeen successfully employed to study ultrafast melting of charge-density-wave inTaSe2 and orbit-order dynamics in La.5Sr1.5MnO4.14

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012REGAE: RF Photoinjector Based UED at DESYPresenter: S. Manz (DESY)S. Manz1, D. Zhang1, A. Casandruc1, J. Hirscht1, S. Bayesteh3, S. Keskin1, M. Felber2,J. Nicholls4, F. Mayet3, M. Hachmann3, T. Gehrke3, S. Jangam1, A. Marx1, S. Hayes1,K. Pichugin1, H. Delsim-Hashemi2, H. Schlarb2, M. Hoffmann2, M. Huening2, G.Moriena4, G. Sciaini1, M. Hada1, K. Floettmann2, R. J. Dwayne Miller1, 41Max Planck Research Department for Structural Dynamics, University ofHamburg, CFEL, Luruper Chaussee 149, 22761 Hamburg, Germany2DESY Hamburg, Notkestrasse 85, 22607 Hamburg, Germany3Institute of Experimental Physics, CFEL, Luruper Chaussee 149, 22761 Hamburg,Germany4Departments of Chemistry and Physics, University of Toronto, Toronto, OntarioM5S 3H6, CanadaThe relativistic electron gun for atomic exploration (REGAE) has been designed tostudy structure and dynamics in a wide range of systems. Aiming for a timeresolution of far less than 100 fs, we plan to observe fast structural changes insolid, solution and gas phase with single-shot femtosecond electron diffraction inthe energy range from 2 – 5 MeV.The presentation will describe theexperimental setup and report on the current status of static electron diffraction.The feasibility of performing real space imaging with REGAE will be discussed aswell.15

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012Lattice Response to Femtosecond Laser Excitation of NickelStudied By Time Resolved Transmission Electron DiffractionPresenter: C. Streubühr (Univ. of Duisburg-Essen)Ferromagnetic Nickel is widely studied in ultrafast magnetism, and directinformation on the femtosecond lattice dynamics is required. Here will present anultrafast transmission electron diffraction study of the lattice response of thinfree-standing Nickel single-crystalline films. The time-dependent diffractionintensities were analyzed and are found to be inconsistent with simple latticeheating. This yet unaccounted disagreement between the experimental resultsand an explanation in terms of simple lattice heating will be shown.16

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012Snapshot imaging of Electron Pulse Dynamics for HighBrightness Ultrafast Diffraction and MicroscopyPresenter: Z. Tao (Michigan State Univ.)We present the methods and results employing the shadow projection imagingtechnique to directly interrogate the space charge effects of the ultrashort,intense photoelectron pulses shortly after photoemission and during the freespace expansion in a dc photo-gun geometry. Combined with analytical Gaussianmodel and ab initio three-step photoemission model with fast multipole method,we elucidate several essential space-charge-led features. The agreementsbetween theoretical models and experimental results enable us to understandthe non-linear effects in space charge dynamics and evaluate its impacts on theperformance of the next generation high-brightness ultrafast electron diffractionand imaging systems.17

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012Movie Mode Dynamic Transmission Electron MicroscopyPresenter: B. Reed (LLNL)The dynamic transmission electron microscope (DTEM) combines pulsed laserswith a modified TEM column to capture the details of fast, irreversible processesin materials. Specifically, the DTEM is designed to capture a complete real-spaceimage in a single nanosecond-scale exposure. This has revealed previouslyinvisible details of phase transformations, microstructural evolution, and solidstate chemical reactions. A recent upgrade the LLNL DTEM yielded a new "moviemode" capability, which captures 9 independent real-space images or diffractionpatterns in the space of a few microseconds, thus enabling an entirely new classof experiments including the quantification of individual nucleation and growthevents.18

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012Granularity effects in high-brightness electron beamsPresenter: B. van der Geer (TU/e/Pulsar Physics)Electron sources based on laser-cooling and trapping techniques are a relativelynew reality in the field of charge particle accelerators. The dynamics of thesesources are governed by stochastic effects, and not by the usually dominantspace-charge forces. As the high-brightness field moves towards increasinglyhigher brightness, these stochastic effects will play an increasingly important role.In this presentation I will discuss the physics of these granularity effects and showtheir effect using molecular dynamics simulations with the GPT code where wetrack each and every particle in realistic fields and including all pair-wiseinteractions.19

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012Four-dimensional electron tomographyPresenter: O.-H. Kwon (Caltech)Electron tomography provides three-dimensional (3D) imaging of equilibriumstructures of materials and biological specimens. Here, we present thedevelopment of 4D electron tomography by integrating the fourth dimension(time resolution) with the 3D spatial resolution obtained from a tilt-series of 2Dprojections of an object. The methodology utilizes the ultimate spatiotemporalresolution of ultrafast electron microscopy, in which femtosecond electron pulsesare chirped [1]. A series of time-framed tomograms constitute a movie, thus,enabling the studies of transient structures, as demonstrated with carbonnanotubes of various modes of vibration [2]. Also presented is stereographicimaging, in analogy to 4D electron tomography, for a nanostructure incomplicated motion [3]. References [1] S. T. Park, O.-H. Kwon, A. H. Zewail, New J.Phys. 14, 053046 (2012).[2] O.-H. Kwon, A. H. Zewail, Science 328, 1668 (2010).[3]O.-H. Kwon, H. S. Park, J. S. Baskin, A. H. Zewail, Nano Lett. 10, 3190 (2010).20

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012Proposed Addition of Ultra-fast Imaging Capabilities toSandia’s In-situ Ion Irradiation TEMPresenter: K. Hattar (Sandia National Laboratory)Understanding the nucleation and interactions of various radiation defectstructures is essential to predicting the performance of systems ranging fromsatellites to nuclear power plants. Sandia National Laboratories’ Ion beam Lab hasrecently developed an in situ ion irradiation transmission electron microscopethat permits real time observation of these interactions. In addition to thenanoscale resolution permitted by the TEM, a sub-microsecond temporalresolution is needed to capture the intermediate structures. These intermediatestructures are essential in identifying the active mechanisms present. Thefeasibility of such an addition to the current system is currently under research.21

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012MeV Electron Diffraction and Microscopy in Osaka UniversityPresenter: J. Yang (Osaka Univ.)The visualization of fundamental dynamic processes in matter occurring onfemtosecond time scales has attracted much attention in chemistry, materialscience and biology. Ultrafast electron diffraction and microscopy (UED and UEM)provide a real-time observation of structural dynamics in matter by recording thechange in the characteristics of electron diffractions or images in the pump stateand the unpump state. We have developed both a relativistic-energy UED and aprototype of relativistic-energy UEM using a femtosecond photocathode RF gun.In this paper, we will report the results of the femtosecond electron bunchgeneration in the RF gun, the ultrafast electron diffractions and the firstexperiments of relativistic-energy electron imaging.22

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012Ultrafast Electron Diffraction with Radio-FrequencyCompressed Electron PulsesPresenter: B. J. Siwick (McGill Univ.)In this talk I will give an overview of ultrafast electron diffraction (UED) usingradio-frequency (RF) compressed electron pulses in the 100keV energy range.The concepts involved in recompressing femtosecond laser produced electronbunches with RF cavities will be discussed along with their practicalimplementation at McGill University.Novel methods to characterize thetemporal impulse response function in pump-probe geometry using laser fieldsand streak cameras will also be described. At pC bunch charges time resolution inthis instrument is 350 fs FWHM, currently limited by RF/laser synchronizationjitter not the recompressed electron pulse duration which we estimate to be 150 /- 50 fs FWHM.The instrument performance in UED experiments will bedemonstrated through two examples involving photo-induced structuraldynamics in materials.23

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012UED Experiments at the X-Band Test AreaPresenter: C. Limborg-Deprey (SLAC)The XTA is a photoinjector equipped exclusively with X-Band RF acceleratorcomponents, a 5.5 cell gun, a linac and a transverse deflector. Early next year, theXTA will be modified with minor changes to run UED experiments.A firstexperiment will utilize ps long electron pulses streaked with the transversedeflector. The second experiment will utilize 10 fs electron pulses out of an RFcompressor. Simulations indicate that 3MeV, kA, 10fs rms, 0.2 mrad e-bunchescould be used. The first experiment will give a reference in view of solving thechallenging issue of synchronization/pulse identification met in single shotexperiments.24

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012Ultrafast Diffraction with Single ElectronsPresenter: F. Kirchner (LMU)We report on the generation of single-electron pulses for advancing ultrafastdiffraction to the time scale of electronic motion. Tailored excitation of metallicphotocathodes produces single-electron pulses with a minimized dispersion anddivergence. A microwave cavity can be used to further compress the wavepackets in time. ‘Isochronic’ magnetic lenses avoid the temporal distortionsintroduced by the imaging system. The transverse coherence of the pulsesexceeds 20 nm, sufficient to cover biomolecular systems. We discuss theperspectives and possibilities that these advancements may bring about.25

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012Sub-fs-precision, Ultrafast Laser-Based Optical and MicrowaveTiming and SynchronizationPresenter: J. Kim (KAIST)I will introduce the most recent progress in subfemtosecond-precision optical andmicrowave timing and synchronization based on ultrafast fiber lasers. The topicswill be (a) the optimization of timing jitter in ultrafast fiber lasers to the sub-fsregime, (b) the extraction of microwave signals from ultrafast fiber lasers withsub-fs jitter and stability, (c) long-distance synchronization of remote ultrafastlasers and microwave sources with sub-10-fs drift maintained more than a week.The combination of these techniques will culminate in a modular, flexible, sub-fsprecision timing system for various types of local and remote ultrafast pumpprobe experiments.26

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012Femtosecond Synchronization of Lasers and Electron BeamsPresenter: J. Byrd (LBNL)I will describe the development of femtosecond synchronization of electronbeams and ultrafast lasers at the fsec level and the its application to accelerators,particularly linac-driven free electron lasers. I will then describe how thesetechniques might be applied to smaller facilities for ultrafast electron diffraction.27

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012Radiofrequency Phase Space Manipulation of UltrashortElectron BeamsPresenter: J. Luiten (TU/e)The development of ultrafast time-dependent electron optics is required to fullyexploit the potential of ultrashort high-brightness electron beams. We areinvestigating various ways to manipulate the 6D phase space distribution ofpulsed electron beams with resonant radiofrequency cavities. Besides bunchcompression, TM-010 cavities may be employed to reduce energy spread and astime-dependent lenses, allowing correction of spherical aberrations. DeflectingTM-110 cavities are usually applied for bunch length diagnostics, but may alsoserve as fast beam choppers, enabling significant improvements of UEM instroboscopic mode. Time-of-flight femtosecond EELS may be realized by thecombination of TM-110 and TM-010 cavities.28

Workshop on Ultrafast Electron Sources for Diffraction and Microscopy ApplicationsDecember 12-14, 2012Innovative Low-Energy Ultra-Fast Electron Diffraction(UED) SystemPresenter: L. Faillace (RadiaBeam Technologies)RadiaBeam, in collaboration with UCLA, is developing an innovative, inexpensive,low-energy ultra-fast electron diffraction (UED) system which allows us toreconstruct a single ultrafast eve

Michelson and spatial interferometers for bunch length measurements Adjustable permanent magnet final focus systems Air- and water-cooled solenoids, spectrometers, quadrupoles and steerers RadiaBeam also has an active research program in collaboration with National Labs and universities. Current topics of interest include: