Overview of x-ray techniques

Transcription

1 Overview of x-ray techniques Makina YABASHI SPring-8/JASRI ICFA Future Light Sources Subpanel Miniworkshop on XFEL Short Bunch Measurement and Timing Stanford Linear Accelerator Center July,

2 XFEL X-beam Handling Short pulse Spatial Coherence Peak Brilliance X-beam Diagnostics 3rd gen. SR 2

3 XFEL X-beam Handling Short pulse Spatial Coherence Peak Brilliance X-beam Diagnostics 3rd gen. SR 3

4 X-ray handling Coherence preservation Temporal manipulation Polarization Thermal handling Nano-beam Monochromator Crystal Multilayer Mirror Window µ fabricated optics 4

5 Crystal: Diamond Diamond ESRF, May 24-25, 2004 Tamasaku et al: "Characterization of synthetic IIa diamonds at SPring-8" Bragg Geometry Si 220(b=20.9)-C kev 5 mm 0.5x0.5 mm 2 Whole surface g 111 Theory 1 mm (Sumitomo IIa) 5

6 Mirror Can we use under coherent illumination? 6

7 Mirror: SP8 - Osaka Univ. collaboration ICFA Future Light Sources Subpanel amera istance: Mirror: Silicon (001) / Incident angle 1.2 mrad / Mirror length 100 mm Premachined surface CVM surface CVM+EEM surface 66 mm 66 mm 66 mm Mori et al, Proc. SPIE (2001) 7

8 Mirror: Nanobeam Summer in 2003 E=15 kev( =0.8 Å) Beam profile imulated by using ideal shape Beam profile simulated by using measured shape Measured beam profile 2.0 Beam profile simulated by using ideal shape Beam profile simulated by using measured shape Measured beam profile Intensity (arb. unit) Intensity (arb. unit) nm nm Position [um] Position [um] July 2004: 40 nm focus was achieved! 8

9 Window: Be NGK, BR-3 Brush-Wellman, IF µm Purity: 98.5 % Roughness: > 1 µm Ra Thickness: 200 µm Purity: 99.8 % Roughness: 0.1 µm Ra Thickness: 250 µm t Phase contrast 1-km BL (0.5 µm res., L ~1.8 m, λ ~1 Å) S. Goto et al: Proc. SRI2003 9

10 XFEL X-beam Handling X-beam Diagnostics 3rd gen. SR 10

11 X-ray diagnostics Coherence Spatial profile Temporal profile Statistics Polarization Crystal Multilayer Mirror Window µ fabricated optics 11

12 Temporal profile Resolution Envelop Repeat Present ~ ps Simple Multi-shot (Gaussian) (average) Target ~ fs, as Complex Single-shot (arbitrary) 12

13 How to measure Temporal domain Laser & X-ray coincidence Fourier transform Frequency domain X-ray Spectral Interferometry 13

14 Spatial profile: Coherence Real-space domain e-beam size measurement Fourier transform Reciprocal-space domain X-ray Interferometry 14

15 Diagnostics Temporal domain Laser & X-ray coincidence Frequency domain X-ray Interferometry Fourier transform Real-space domain e-beam size measurement Reciprocal-space domain X-ray Interferometry 15

16 Interferometry Amplitude interferometry Intensity interferometry Thomas Young, 1807 Hanbury-Brown and Twiss, 1956 Photon Statistics 16

17 Photon statistics Aug. July ! Chaotic light Coherent light Intensity interferometry (2nd-order interferometry) 17

18 Contents Introduction Principle Experiment at 3rd. gen SR Proposal for SPPS Proposal for XFEL 18

19 Instantaneous wave field Point / Coherent source Point / Chaotic source 2π ir i t Ert (,) Ne exp e ω λ Planer /Chaotic source N e 2π ir i Ert (,) exp + iφi () t e ω λ i t N e 2π ir si i t Ert (,) exp + iφi () t e ω i λ Loudon, 1983 Goodman,

20 Wave packet temporal coherence length I = I + I +Γ +Γ Γ = * AB A B * A B AB A EE coherence cell spatial coherence length xt, ) = ( xt, ) 2 IAIB = IA IB + ΓAB 2 20

21 Variation Two pinholes d One pinhole + Beam splitter x 21

22 Mode number Spatial resolution M X ~ 3 M T ~ 2 Temporal resolution coherence cell Coincidence counter ode number M : Number of coherence cells n the resolution function (M = M X M Y M T ) I AIB = IA IB 1+ 1/ M IAIB 1 R 1 = I I M A B ( ) Small M Large R M X 1 10 R w X /σ X 22

23 Contents Introduction Principle Experiment at 3rd. gen SR Spatial domain Temporal domain Proposal for SPPS Proposal for XFEL 23

24 Difficulty in 3rd gen. SR M T s T = 1+ σ T 2 s T ~ ps (pulse width of SR) σ T ~ sub-fs (N U λ/c) for raw undulator radiation M T ~ R =1/ M T ~ σ T = λ 2 / λ = λe/ E 1/ E Use of high-resolution monochromator (HRM) Optimized condition: σ ~ s T T (~ 10 ps) E ~ sub mev Y. Kunimune et al. JSR (1998) E. Gluskin et al. JSR (2000) 24

25 High-Resolution Mono 10 E (mev) E/E = ω S cot θ B Year E/E = ω S b 1/2 cot θ B Energy Resolutions at E=14.4 kev G. Faigel et al. 1987; T. Ishikawa et al. 1992; T. Toellner et al. 1992, 1997; A.I. Chumakov et al. 1996, E/E 25

26 Design E = 14.4 kev Si Glancing angle = 2 b = b 1 = b 2 = 1/b 3 = 1/b 4 = 1/10.4 Crystal size: mm 3 Spatial acceptance = 100 µm E = 100 µev 26

27 Dual co-axial goniometer #2 Dual co-axial goniometer #1 (12.2 nrad/pls) 27

28 Result Resonant intensity Slit width: 100(v) x 22.5(h) µm 2 E= 114 µev Energy shift (µev) 28

29 Achieved Resolution 10 E (mev) Year M. Yabashi, K. Tamasaku, S. Kikuta, and T. Ishikawa, Rev. Sci. Instrum. 72, 4080 (2001) E/E 29

30 Setup 25 m/4.5 m Undulator DCM HRM Slit APD 1& Distance from the center of undulator (m) The rotation center of θ CCD camera APD 1 APD 2 Cage for the 2nd crystal exit beam α 1 30mm incident beam Y1 XX 1 φ 1 Z1 mechanical cam X1 Cage θ 1 θ itamura et al., NIM A, 2001 manual X manual Z Yabashi et al., SPIE 1999; Tamasaku et al., SPIE 2002, TM P BS APD 1 APD 2 30

31 σ y λz = 2π s y ε = 6 nm.rad Spatial domain ε = 3 nm.rad R Vertical slit width ( µm) σ y = ± 6.9 µm s y = 5.9 ± 0.3 µm ε y = 6.0 ± 0.7 pm.rad κ = 0.10 % R max. Yabashi, K. Tamasaku & T. Ishikawa, ys. Rev. Lett. 87, (2001); ys. Rev. A 69, (2004). R Vertical slit width ( µm) σ y = ± 5.0 µm s y = 4.6 ± 0.14 µm ε y = 3.6 ± 0.2 pm.rad, κ = 0.12 % 31

32 Pulse width R max 0.2 R Vertical slit width (µm) R max = 1/ M T = (1+ σ T 2 /s T2 ) -1/2 (M X = M Y = 1) σ T = 4hln2/ E Measure pulse width s t 32

33 Result R Vertical width = 30 µm E(keV) E(meV) Horizontal slit width ( µm) 33

34 Mode number vs. bandwidth M t 10 5 Measured Calculated (s=32.7 ps) t M t = 1/ R max 4 ln2 = 1+ E s t 2 s T = 32.7 ±1.6 ps E (mev) Streak camera: 32 ps M. Yabashi, K. Tamasaku, and T. Ishikawa, Phys. Rev. Lett. 88, (2002). 34

35 Contents Introduction Principle Experiment at 3rd. gen SR Proposal for SPPS Proposal for XFEL 35

36 SPPS Pulse Optimized width bandwidth 3rd gen. 30 ps 0.2 mev complicated SPPS 80 fs 70 mev simple 36

37 Pinhole Intensity monitor Proposed Setup Si hkl Ge detector MCA light det. t M 2 K = σ K 2 K 37

38 E (mev) Simulation M Mandel's formula Si Si Si E = 9.3 kev, s t = 80 fs average counting number = 2.5 Probability Photon counting number B-E Poisso 38

39 Key for success 1. Bose degeneracy S/N δ η (f T)1/2 SP8 25-m U SPPS Degeneracy δ : ~ 0.3 ~ 90 (B P ~ (B P ~ λ ~0.086 nm ) λ ~0.13 nm) Efficiency η: Repetition rate f : 36 MHz 10 Hz δ η f 1/2 : Time: ~ 10 min < 10 min?? 2. Normalization of intensity fluctuation unrelated to interference 39

40 Required time Estimated M c 10 5 Time (s) δ c =1 δ c = Total number of pulse, N δc # of pulses Time sec sec ~ 1 hour sec ~ 2 days 2 T δ c 40

41 Key for success 1. Bose degeneracy S/N δ η (f T)1/2 Degeneracy δ : ~ 0.3 ~ 90 (B P ~ (B P ~ λ ~0.086 nm ) λ ~0.13 nm) Efficiency η: Repetition rate f : 36 MHz 10 Hz δ η f 1/2 : Time: ~ 10 min < 10 min?? 2. Normalization of intensity fluctuation unrelated to interference 41

42 Average for repeated pulses I I I ω ω ω More intense beam 42

43 Single-shot Measurement ( E) 2 E 1 A ( t) 2 T 2 E 2 E FT ' Microstrucrure Envelop T 1 t T 1 h / E 1 J. Krzywinski, E. Saldin et al. NIM A (1997) 43

44 Simulation Time (fs) Photon energy (ev) T 1 : 100 fs E 1 : 10 mev Photon energy (mev) 44

45 XFEL Thin target/ Divergent optics Setup Crystal (Si, Ge, C...) Nearly backscattering E E χ g Array Detector I( E) = A( E) 2 Si 555: E = 16 E 9.9 kev Pulse width estimation (a priori knowledge of pulse shape) OK 45

46 Detailed information FT A E A t 2 ( ) ( ) 2 FT A E A t Require phase information ( ) ( ) 46

47 Phase retrieval Oversampling method 2D: OK Miao et al. PRL 89 (2002) FT 2 Iteration SEM image of Ni pattern on SiN Coherent Scattering Pattern 2D Reconstructed Image (<10 nm resolution) 1D: generally impossible for complex object 47

48 Example: FROG Frequency Resolved Optical Gating Measure energy spectrum with changing delay time Optical Delay Spectrometer Non-linear material 2D Phase Retrieval R. Trebino and D. J. Kane, JOSA A (1993). XFROG? 48

49 Summary We can apply intensity interferometry to measure spatial and temporal profile of 3rd gen. SR source. For shorter pulse, much easier. For single-shot detection, extension of conventional spectroscopy technique will be useful. For determination of pulse shape, we have to retrieve phase information. Further considerations & discussions are required. 49

50 Acknowledgement T. Ishikawa, K. Tamasaku, S. Goto, D. Miwa, T. Ueda, A. Baron H. Kitamura, T. Shintake, T. Hara, H. Tanaka (SPring-8) K. Yamauchi, K. Yamamura, H. Mimura, T. Matsuyama, H. Yumoto, Y. Mori (Osaka Univ.) J. Hastings, J. Arthur (SLAC) 50