C. Masciovecchio. Introduction EIS (TIMER & TIMEX) DIPROI

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1 based scattering experiments C. Masciovecchio Introduction EIS (TIMER & TIMEX) DIPROI

2 The Inelastic ScatteringTeam A. Battistoni, F. Bencivenga, R. Cucini, F. D Amico, S. Di Fonzo, A. Gessini, E.Giangrisostomi, E. Principi Available Spectroscopies Inelastic Scattering: Synchrotron and CW table-top laser Raman and Resonant Raman: Synchrotron and CW table-top laser Transient Grating: Free Electron Laser (FEL) and femtosecond table-top laser Ultrafast Pump&Probe: Free Electron Laser (FEL) and femtosecond table-top laser

3 Why Free Electron Lasers? Time-scales of dynamic processes occurring in matter Intermolecular energy transport Chemical transformations Electron-spin dynamics Domain dynamics Diffusion e-ph/ph-ph scat Imaging with high Spatial Resolution (~ l): fixed target imaging, particle injection imaging,... Dynamics: four wave mixing (time profile), warm dense matter (uniform heating), extreme conditions, Resonant Experiments: XANES (tunability), XMCD (polarization), chemical mapping,

4 Free Electron Lasers SASE (Self Amplified Spontaneous Emission) LCLS (Stanford - USA) XFEL (Hamburg - Germany) SCSS(Jaery Riken - Japan) FLASH (Hamburg - Germany) In a world of big dinosaurs a small one has to be smart to survive. L. H. Yu et al., 91, PRL (2003)

5 Intensity (a.u.) Energy Distribution Dec 2010 March Tunability: (fast) 5 20% at a given Energy Polarization: Circular V and H Beam Profile: ~ Transform Limited ( fs) Relative Photon Energy (mev)

6 Temperature (ev) Elastic and Inelastic Scattering (EIS) beamline C. Masciovecchio A. Di Cicco, R. Gunnella, E. Principi (University of Camerino); A. Filipponi (University of L Aquila); R. Torre (LENS); G. Ruocco, T. Scopigno (University of Rome); F. Sette (ESRF); F. Bencivenga, D. Cocco, F. D Amico, R. Cucini, M. Zangrando, A. Gessini, F. Parmigiani (Sincrotrone Trieste) Short pulses with very high peak power What happens to the Sample? The Sample Side Dt ~ 100 fs ; Peak Power ~ 5 GW ; E ~ 100 ev Non-equilibrium distribution of electrons Converge (electron-electron & electron-phonon collisions) to equilibrium (Fermi-like) During this complex dynamics atoms go through a relaxation process due to the dramatic changes of the potential energy surface The intensity of the FEL pulses will determine the process to which the sample will undergo: simple heating, structural changes, ultrafast melting or ultrafast ablation 1.0 T E MAX Lattice T MAX L Electrons Time (ps) T E MAX T L MAX TIMER Dt, Peak Power, E, Sample, Fluence,.. TIMEX

7 EIS beamline - TIMER BL10.2 BL30/21 TIMER TIME-Resolved spectroscopy of mesoscopic dynamics in condensed matter Challenge: Study Collective Excitations in Disordered Systems in the Unexplored w-q region Determination of the Dynamic Structure Factor: S(Q,w) Q (q) q 10 2 BLS 10 1 IXS w = c s Q 10 0 IUVS w (mev) INS macro-scale nano-scale atomic-scale Q ( nm -1 )

8 Why Disordered Systems? Unsolved problems in physics Condensed matter physics Amorphous solids What is the nature of the transition between a fluid or regular solid and a glassy phase? What are the physical processes giving rise to the general properties of glasses? High-temperature superconductors What is the responsible mechanism that causes certain materials to exhibit superconductivity at temperatures much higher than around 50 Kelvin? Sonoluminescence What causes the emission of short bursts of light from imploding bubbles in a liquid when excited by sound? Turbulence Is it possible to make a theoretical model to describe the statistics of a turbulent flow (in particular, its internal structures)? Also, under what conditions do smooth solution to the Navier-Stokes equations exist? Plateau in the Thermal Conductivity, Excess in the V-DoS (Boson Peak), Specific Heat

9 S(Q,w) (arb. units) EIS beamline - TIMER The understanding of collective dynamics nature in glasses at the nanoscale is still unclear P. Benassi et al., PRL 77, 3835 (1996) Existence of propagating excitations at high frequency M. Foret et al., PRL 77, 3831 (1996) They are localized above SiO ~ 1 nm -1 2 F. Sette et al., Science 280, 1550 (1998) They are acoustic-like T = 1075 K G. Ruocco et al., PRL 83, 5583 (1999) Change of sound Q = attenuation 1.6 nm -1 mechanism at nm -1 B. Ruffle et al., PRL 90, (2003) Change is at 1 nm -1 C. Masciovecchio et al., PRL 97, (2006) Change is at 0.2 nm -1 W. Schirmacher et al., PRL 98, (2007) Model agrees with Masciovecchio et al. B. Ruffle et al., PRL 100, (2008) Shirmacher model is not correct G. Baldi et al., PRL 104, (2010) -10 Change 0 is at 1 nm 10-1 w (mev) European Research Council ERC Starting Grant Research proposal Funded Grant: 1.8 M

10 w (mev) 10 2 BLS IUVS EIS beamline - TIMER IXS Solution: Free Electron Laser based Transient Grating Spectroscopy E signal F(Q,t) INS E pump Q(l,q) q Q ( nm -1 ) S(t) ( cost F(Q,t)) E probe E pump Sound waves region region Thermal region Glycerol T=205 K

11 S(Q,w) (a.u.) F(Q,t) (a.u.) w (mev) 10 2 BLS IUVS EIS beamline - TIMER IXS Solution: Free Electron Laser based Transient Grating Spectroscopy E signal F(Q,t) INS E pump Q(l,q) q Q ( nm -1 ) E probe E pump H 2 O 2 nm w (mev) -0.8 Gaussian-like time profile t (ps)

12 Typical Infrared/Visible Set-Up M Delay Line l 1 Probe laser beam DM l 2 =2l 1 Excitation laser beam Phase Control (Heterodyne) Beam stop (Homodyne) Neutral Filter (Heterodyne) E ex1 E L APD M DOE: Phase Mask E pr Sample AL1 E ex2 AL2 E s (Homodyne) E L +E s (Heterodyne) Challenge: Extend and modify the set-up for UV Transient Grating Experiments

13 TIMER Layout Delay line: 4 ML mirrors (abs 1 st, reflect 3 rd harm), time delays up to ~ 3 ns 3 rd harmonic (probe) 2θ θ B Beam waist Original beam Vertical Pump1 Pump2 FEL pulse:1 st and 3 rd harmonic (λ 3 = λ 1 /3) Focusing mirror Plane Mirrors beam splitters 1 st harmonic (pump) Horizontal sample position Vertical Horizontal R. Cucini et al et al., NIMA (2011)

14 Expected TG formation Δρ/ρ 8x10-4 SiO 2 sample Relative density variation (@ z=0, considering only the optical absorption of pump radiation) sample position (@ z=0, λ=60 nm, θ=9.2 periodicity demagnified by a factor 100 for clarity) 2c σ t 2σ A(x,y,z)cos(Qy) Intensity (arb. (arb. units) units) x y 840 J kg -1 K -1 0 Δρ/ρ(x,y,z) ~ αδe(x,y,x)/(δvc v ρ) 2L abs 2σ K kg m -3 Adiabatic heating of the sample in the illuminated region < 3 C Expected count rate: counts per pulse

15 EIS laser lab Ti:sapphire laser + regenerative amplifier Amplifier output: 100fs/800nm/3mJ 1 khz repetition rate

16 TG signal EIS laser lab Liquid sample (dimethylsolfossil) Electronic peak energy ~ 1 10 nj Pump energy ~ 25 μj/pulse Probe energy ~ 5 μj/pulse Beam dimensions ~ μm θ = 26, Δt=150 fs, λ=800 nm Signal ~ pj I signal /I probe ~ t (ps) Signal ~ [A sin(ωt)e -Γ 1 t + B(1-cos(ωt))e -Γ 2 t ] 2 Sound velocity = /- 2 m/s (OK) R. Cucini et al et al., Opt. Lett. (2011)

17 HHG-TG in a Gas Jet The harmonic signal encodes structural information on the orbital full reconstruction...high harmonic transient grating spectroscopy can be extended to all forms of molecular excitation and to weak resonant excitation...

18 HHG-TG to observe Chemical Reactions in Real Time

19 Diffusion Experiments Heat Transport, Diffusion Phenomena, Flow Studies, Concentration Grating, Electronic Energy Transfer, Photochemical Reactions, Optical Damage H. J. Eichler et al., J. Appl. Phys. 44, 5455 (1973)

20 Spin Dynamics TG can excite Spin Waves using orthogonal polarization Spin Diffusion and Relaxation in a 2-dim. Electron Gas

21 EIS beamline - TIMEX TIMEX TIme-resolved studies of Matter under EXtreme and metastable conditions Temperature (ev) Generation of warm dense matter (WDM) in simple metals (Al,Au, etc ): looking for EoS studying the FEL-induced isochoric heating followed by isoentropic expansion Melting of carbon (diamonds/graphite) Generation of metastable liquids in a no man's land through ultrafast heating of amorphous states (Si, Ge...) Al phase diagram FEL pulses allow uniform heating: 500 Å Al uniformly heated at 1 ev (10000 K) Dt = 200 fs, l = 6 nm, d = 150 mm, ph/pulse A. Di Cicco et al., SPIE (2011)

22 The Pyrometer The heat transport after WDM excitation in a sample foil can be reliably described by heat equations with an additional term (radiation loss at sample surfaces) T(r,t) displays a peak (fast rise and slow decay in an accessible timescale: ~1 10 μs) which contains information on the initial temperature profile E. Principi et al., NIMA (2010), E. Principi et al., submitted to APL

23 Absorption TIMEX: instrumental layout Transmission Microscope (~3 μm resolution) Transmission detector (avalanche photodiode) FEL focusing chamber (elliptic mirror, f=1200 mm) FEL pump Optical laser as alternative pump Pyrometer FEL probe Sample 3 rd harm. probe Detector 1 st harm. pump 0,8 Silicon Probe (FEL) 0,4 Wavelength 0, Energy (ev)

24 Scattering Imaging DIPROI beamline M. Kiskinova H. Chapman, S. Bajt, L. Gumprecht (DESY); A. Barty, B. Woods, M. Bogan, E. Spiller, M. Pivovaroff, A. Nelson (LLNL); U. Vogt, H. Hertz (KTH Stockholm); G. Morrison (King s College); D. Cojoc (TASC); F. Capotondi, D. Cocco, E. Pedersoli, M. Zangrando, F. Parmigiani (Sincrotrone Trieste) Limitations of available techniques: Scanning microscopes are limited to surfaces Transmission electron microscopes are limited in penetration (samples thinner than ~ 30 nm) Stepping into nano-world X-ray crystallography reveals the 3D atomic structures, but requires crystals X-ray microscopes are limited in resolution by the optical elements, and coherence The optic-imposed resolution limitations can be overcome by image reconstruction from the measured coherent X-ray diffraction pattern of a sample

25 Stereo coherent diffraction imaging Example: J. Nelson et al, PNAS The relationship of cell s internal structures can only be determined accurately by full 3-D imaging FEL: 3D CDI-for random orientation delivery: via classification (Hajdu, Chapman) 2θ

26 DIPROI beamline Specific element-sensitive Abrupt changes in the X-ray scattering cross section near electronic resonances: the difference in CDIs can be used for make a chemical map of a specific element Song et al., PRL 100, 25504, 2008 Buried Bi structures inside a Si crystal with a pixel resolution of ~ 15 nm DPC Fe Co CoFe 2 O 4 in mouse 3T3 fibroblast cells...this imaging technique is also sensitive to chemical states via near-edge resonances and can be extended to exploit other contrast mechanisms depending on resonant transitions such as x-ray magnetic circular dichroism...electronic orbital as well as chemical state specific imaging of magnetic materials, semiconductors, organic materials, biominerals, and biological specimens... Fe M II 3p 1/2 is at ~ 53 ev

27 DIPROI beamline Gaps in our current understanding of effect of Nano-Objects (NOs) introduced in biological systems and vice-versa (cell targeting, drug delivery, etc) N. Lewinski et al., Small 4, 26, (2008) Today NOs production is ~ 2000 tons in 2020 will be ~ tons!! Oxidative damage due to catalysed generation of reactive oxygen species, ROS, (OH, O 2-, H 2 O 2 ) impact on the NOs? Bond breaking and release of free radicals or molecules impact on the NOs? UV -Photochemistry (NOB) H 2 O OH - h + e - O - 2 e - O 2 FEL Me ++ H 2 O 2 OH - - CCD Sample(s) Imaging to study the alteration of cell s morphology due to the presence of NOs and determine their spatial distribution

28 Conclusions has unique capabilities due to the electron acceleration scheme FEL based Transient Grating Spectroscopy is a very useful technique for the study of collective excitations in disordered systems like liquids and glasses. It will be extremely useful also to measure correlations, electronic excitation lifetimes, transport properties, intramolecular dynamics and non-linear material responses. HHG-TG allows fully coherent spectroscopy - amplitude and phase. TIMEX will provide first results in Dec DIPROI is currently under construction and will exploit the unique features of FERMI@elettra to carry out CDI experiments