Matter in Extreme Condition at X-ray Free-Electron Lasers

Transcription

1 Matter in Extreme Condition at X-ray Free-Electron Lasers Bob Nagler

2 Collaborators (amongst many others...) Orlando Ciricosta, Colin Brown, Andrew Higginbotham, Christopher Murphy, Justin Wark University of Oxford Byoung-ick Cho, Kyle Engelhorn, Roger Falcone, Phillip Heimann Lawrence Berkeley National Laboratory Bob Nagler, Hae Ja Lee, Eric Galtier, Jacek Krzywinski, Mark Messerschmidt, William Schlotter, Joshua Turner, Catherine Graves, Tianhan Wang, Benny Wu, Diling Zhu, Andreas Scherz, Jerry Hastings, Johannes Schrop SLAC National Accelerator Laboratory Hyun-Kyung Chung IAEA Yuan Ping, Damian Hirsch Lawrence Livermore National Laboratory Tomas Burian, Jaromir Chalupsky, Vera Hajkova, Ludek Vysin, Libor Juha IOP, Academy of Sciences of the Czech Republic Sven Toleikis, Marion Harmand, Thomas Tschencher DESY Ulf Zastrau 2

3 Outline Matter in extreme conditions and high energy density systems X-ray Free-Electron Lasers are ideal First experiments Summary 3

4 Matter in extreme conditions Courtesy of Richard W. Lee 4

5 Matter in extreme conditions occurs widely in nature A.M. Dziewonski and D. L. Anderson Physics of the Earth and Planetary Interiors 25, 297 (1981). S. K. Saxena & L. S. Dubrovinsky, American Mineralogist 85, 372 (2000). J. C. Boettger & D. C. Wallace, Physical Review B 55, 2840 (1997). C. S. Yoo et al., Physical Review Letters 70, 3931 (1993). 5

6 Matter in extreme conditions occurs widely in nature Jupiter Metallic H: 200GPa 1eV core H: ~5000GPa ~10eV 6

7 Matter in extreme conditions occurs widely in nature Hot Dense Matter (HDM) supernova, stellar interiors, accretion disks plasma devices, laser produced plasmas, Z- pinches directly and indirectly driven inertial fusion Warm Dense Matter (WDM) cores of large planets, gas giants transient state in X-ray driven inertial confinement fusion systems that start solid and end as a plasma 7

8 Matter in extreme conditions Matter in Extreme Conditions High Density High temperature High Pressure, shocks 8

9 Challenges : numerical code comparison Iron 16 <Z> average charge state Temperature (ev) Courtesy of Richard W. Lee 9

10 Challenges : EOS numerical code comparison Equation of State: relation between N, P, T Iron Copper Courtesy of Richard W. Lee 10

11 11

12 Theoretical Challenges: = V Coulomb E Kinetic 12

13 For Solid V_coulomb (quick estimate): F c = 1 q r 2 V c ' F c r 13

14 For Solid V_coulomb (quick estimate): q ~ 1e r~0.5nm V_c~5eV F c = 1 q r 2 V c ' F c r E_thermal ~ kb T ~ 25meV (room temperature) '

15 For Plasma V c ' 1 q r 15

16 For Plasma V c ' 1 q r V_c = 1-10eV E_thermal = 1000eV eV '

17 Theoretical challenges: Atomic Physics Debye (screening) Length: For solid density (~2 10^28 m^-3) and kbt~10ev, we get: D ' 1A 17

18 Challenges : EOS numerical code comparison Iron Copper 18

19 MEC studies with XUV and X-ray FEL radiation Optical laser excitation XUV and X-ray laser excitation < p > p < p is typically ev (UV) sam.vinko@physics.ox.ac.uk

20 Requirements 1. XUV or X-ray wavelength 2. Short pulses, sub-ps) 3. Lots of photons

21 Matter in extreme condition at 4th generation light sources MEC at LCLS: Matter in Extreme Condition instrument HEDS instrument at the European X-FEL Experiments at other Facilities: FLASH: WDM creating Thomson Scattering on Dense He Experiments at LCLS on existing end-station: SXR: solid density Al Plasma Plasma kinetics in Al Plasma XPP: Diffraction on Shocked Iron Fourier Domain Interferometry on X-ray heated matter CXI: Diffraction on Shocked Iron

22 Highlight 4 experiments Creating Transparent Aluminum in Flash Measuring highly ionized charge states in solid Al at SXR, LCLS Shock experiments and Equation of State 22

23 Gas monitor detector Gas attenuator Aperture Fast shutter 13.5 nm Multilayer coated off-axis parabola 3 mm Target samples: Al, Mg, Si3N4 Photodiode Target stage scans through focus 4 µm Al filter sam.vinko@physics.ox.ac.uk

24 Aluminium Magnesium Binned Binned Transmission Transmission x x x x10 16 Intensity (W/cm 2 ) 0 1x x x x x10 17 Intensity (W/cm 2 ) sam.vinko@physics.ox.ac.uk

25 Saturable absorption in the XUV Silicon nitride Transmission Binned 1x x x x10 16 Intensity (W/cm 2 ) sam.vinko@physics.ox.ac.uk

26 Saturable absorption in Aluminium L-edge Electron configuration in atomic aluminium: (µm -1 ) ω p 1s 2 2s 2 2p 6 3s 2 3p 1 K L M σ ff 3s 2 3p 1 2p 6 E phot 2s 2 2p 6 K-edge 1s 2 sam.vinko@physics.ox.ac.uk

27 L-edge shift ω fel =92eV E f 73eV 118eV 2s 2 2p 6 sam.vinko@physics.ox.ac.uk

28 L-edge shift ħω= 92 ev E f 73eV 118eV 2s 2 2p 6 sam.vinko@physics.ox.ac.uk

29 L-edge shift E f ω fel =92eV 93.5eV 2s 2 2p 5 sam.vinko@physics.ox.ac.uk

30 Saturable absorption in the XUV Aluminium Experimental Data, binned Theoretical transmission, 15fs pulse Theoretical transmission, 35fs pulse Magnesium Experimental Data, binned Theoretical transmission, 15fs pulse Theoretical transmission, 35fs pulse Transmission x x x x x x10 17 Intensity (W/cm2) Silicon Nitride Transmission x x x x x x10 17 Intensity (W/cm 2 ) Transmission Experimental Data, binned Cold transmission in the low intensity limit: - 52nm Al oxide: 16% - 52nm Mg + 20 nm Al + oxide: 10% - 83 nm SiN: 65% Effective measure of the core-hole fraction! Nagler et al. Nature Physics 5, 1341 (2009) 0 1x x x x x10 17 Intensity (W/cm2) sam.vinko@physics.ox.ac.uk

31 Temperature in Solid Aluminum Target

32 Temperature in Solid Aluminum Target

33 Multilayer coated off-axis parabola XUV spectrometer Gas monitor detector 5 mm 92 ev Target sample holder scans through focus sam.vinko@physics.ox.ac.uk

34 Probing Warm Dense Matter on FLASH: L-shell spectroscopy L-shell photo-excitation Radiative recombination Solid, crystalline aluminium ħω FEL photon excited a L-shel core state ħω= 92 ev Emitted photons map the occupancy of the valence band sam.vinko@physics.ox.ac.uk

35 Intensity / Energy W/cm W/cm W/cm W/cm W/cm W/cm W/cm 2 Al IV emission lines T=1.1 ev T=0.9 ev T=0.8 ev T=0.4 ev Energy (ev) Scanned 3 orders of magnitude in intensity Fluorescence overlaps with atomic emission lines from dilute plasma Valence band emission takes place ~40 fs after the first arrival of FEL pulse Measures the average temperature and density immediately after the pulse Vinko et al., PRL 104, (2010) Temperature (ev) classical plasma Γ = 1 dense plasma Γ = 10 Γ = 100 high density matter Density ( g/cm3) sam.vinko@physics.ox.ac.uk

36 LCLS:SXR experimental setup X-ray spectrometer: Al K-alpha emission ev ADP (101) crystal CCD LCLS pulse Photon energy: ev Pulse length < 80 fs Pulse Energy ~1.5 mj Bandwidth ~ 0.4% 1 micron thick Al sample Diode Peak Intensity ~10 17 W cm -2 S. Vinko, Nature 482 (2012)

37 Electronic structure of Aluminium Neutral Al Photo-excitation L-edge LCLS (µm -1 ) ω p L: 2s 2 2p 6 σ ff 3s 2 3p 1 2p 6 2s 2 2p 6 1s 2 K-edge E phot K: 1s 2 37

38 Electronic structure of Aluminium Neutral Al K-alpha emission L-edge LCLS (µm -1 ) ω p L: 2s 2 2p 6 σ ff 3s 2 3p 1 2p 6 2s 2 2p 6 1s 2 K-edge E phot K: 1s 1 38

39 Electronic structure of Aluminium Ionized Al Photo-excitation L-edge LCLS (µm -1 ) ω p L: 2s 2 2p 3 σ ff 3s 2 3p 1 2p 6 2s 2 2p 6 1s 2 K-edge E phot K: 1s 2 39

40 Electronic structure of Aluminium Ionized Al K-alpha emission L-edge LCLS (µm -1 ) ω p L: 2s 2 2p 3 σ ff 3s 2 3p 1 2p 6 2s 2 2p 6 1s 2 K-edge E phot K: 1s 1 40

41 K-shell spectroscopy of Hot Dense Aluminium single K holes double K holes IV K-alpha emission Physical recombination process V VI VII VIII Conduction band Continuum level Intensity (a.u.) IX X XI V VI VII VIII IX X L-shell K-alpha VII K-shell Photon Energy (ev) FEL photon energy: 1830 ev S. Vinko, Nature 482 (2012)

42 K-shell spectroscopy of Hot Dense Aluminium IV V VI VII VIII IX X XI V VI VII VIII IX X 1826 ev 1803 ev 1767 ev Intensity (log a.u.) 1753 ev 1727 ev 1702 ev 1679 ev 1653 ev 1628 ev 1602 ev 1578 ev Photon Energy (ev) 42

43 Experimental Data FEL jitter seen to be significant - strong dependence of emission spectra on the excitation wavelengths warrants binning the results in wavelength Pumping photon energies! Step size of histogram : 5eV! above edge pumping (run 54~72) FEL hv distribution xrayetable_above_edge_hist average hv for each run # of shots Run! FEL photon energy (hv) [ev] 54/56 57/58 59/60 61/ /69 70/

44 K-shell spectroscopy of Hot Dense Aluminium 1820 I-IV V VI VII VIII IX X XI II-V VI VII VIII IX X 3e+07 3! e+07 1! X-ray Energy FEL of x ray photon FEL excitation energy (ev) (ev) e+06 3!10 6 1e+06 1!10 6 Emitted photon number (sr -1 ev -1 ) ! Emitted photon energy (ev) Emitted photon energy (ev) !10 5 S. Vinko, Nature 482 (2012)

45 Charge state distribution - CSD 0.35 Fractional yield integrated over pulse ev 1630 ev 1680 ev 1730 ev 1780 ev 1830 ev Charge state S. Vinko, Nature 482 (2012)

46 K-shell spectroscopy of Hot Dense Aluminium 1820 IV V VI VII VIII IX X XI V VI VII VIII IX X 3e e K-edge X-ray Energy FEL of x ray photon FEL energy excitation (ev) (ev) Resonance transitions 3e e Emitted photon number (sr -1 ev -1 ) Emitted energy (ev) Emitted photon energy (ev) S. Vinko, Nature 482 (2012)

47 Electronic structure of Aluminium Photo-excitation K-alpha emission L: 2s 2 2p 3 L: 2s 2 2p 3 K: 1s 2 K: 1s 1 47

48 CSD and emission spectrum 1820 IV V VI VII VIII IX X XI V VI VII VIII IX X 3e X-ray Energy FEL of x ray photon FEL energy excitation (ev) (ev) K-edge Resonance transitions 1e e e Emitted photon number (sr -1 ev -1 ) Fractional yield integrated over pulse ev 1630 ev 1680 ev 1730 ev 1780 ev 1830 ev Charge state Emitted energy (ev) Emitted photon energy (ev) S. Vinko, Nature 482 (2012)

49 Plasma parameters: electron temperature 200 Temperature (ev) ev 1630 ev 1680 ev 1730 ev 1780 ev 1830 ev Time (fs) S. Vinko, Nature 482 (2012)

50 Plasma parameters: free-electron density 6x10 23 Density (electrons cm -3 ) 5x x x x ev 1630 ev 1680 ev 1730 ev 1780 ev 1830 ev 1x Time (fs) Ion density of solid-state Al (2.7 g cm -3 ) S. Vinko, Nature 482 (2012)

51 Conclusions First experimental results looking at high-intensity X-ray FEL interaction with solid density Al samples: dynamics are very different to single-atom case; Electron collisional processes dominate the CSD, even in the presence of the intense X-ray pulse; simulations indicate thermal CSD within a fraction of the pulse Temperatures in excess of ev achieved at solid densities; Absorption/heating determined by the ionized states, ground-state cross sections largely irrelevant! Emission spectrum generated by a quasi-monochromatic X-ray pulse is not necessarily representative of the CSD, but is sensitive to the K-edges of the excited system. 51

52 Shock physics and Equations of State N P T shock velocity Z 52

53 Shock physics and Equations of State Density shock velocity Z Continuity of Mass, Momentum, Energy over shock front 3 equations, 5 unknowns 53

54 VISAR diagnostic for High Pressure Physics F(r) Line-imaging velocimeter for shock diagnostics, P. Celliers et al., Rev. Sci. Instr., 4916, 75, (2004) Courtesy of Wark et al.

55 Conclusion X-ray FELs are a game changing tool in MEC science