XAFS 6.5GeV PF-AR 2.5 GeV PF XAFS QXAFS DXAFS XAFS XAFS 1
XAFS X 2.342keV K SCe L Nb * 2
XAFS XAFS * 3
Cu XAFS 5 days * M. Nomura, A. kazusaka, Y. Ukisu and N. Kakuta, J. Chem. Soc., Faraday Trans., 83, 2635 (1987). 4
a. b. c. d. e. 5
* a. t = fm /(I 0 n) t f 1 I 0 m: XAFS n: XAFSS/N I 0 (x) d =0.245 T X=2.55 S/N=1 A / T =10 4 f=310 8 f A / T =10 3 f=310 6 N S 0. 556 A Rev. Mod. Phys., 53 (1981) 769. T 6
x) 0 = 0.245 X=2.55 S/N S/N = 0.556 A / (I IN ) 1/2 A XAFS I IN I IN = 810 8 ph x) 0 = 0.12 k 3 =1A -3 at k=16a -1 k=16a -1 S/N 16 3 =4096 =210 background 7
PFXAFS-BL 7C NW2A 9A 12C 310 10 ph/s NW10A 9C 12C * 8
t = fm /(I 0 n) t f I 0 m: XAFS n: XAFSS/N (x) d =0.556 [I 0 ] T X=2.55 []S/N=1 A / T =10 4 f=310 8 A / T =10 3 f=310 6 Rev. Mod. Phys., 53 (1981) 769. N S 0. 556 T A f I 0 =310 10 ph/sf=310 8 n=1m=1 t=10ms m=1000 t=10s ** 9
S/NX (1/n) X 10
X 9ABLIC BL-9AMnO 4 * 11
b. 36000 pulse/deg 8000 pulse/s 4.5s/deg * Si(111) 2021keV 0.25 1516keV 0.48 1011keV 1.05 56keV 4.05 34keV 11.60 sin 1 ( hc ) 2dE Bragg 12
c. ms 100msrise time (Keithley 427) rise time) 10 8 V/A 110 11 A (60s), 210 12 A (1ms) 10 10 V/A 210 12 A(400s), 210 14 A (100ms) 10 11 V/A 410 13 A(1.5ms), 310 15 A (330ms) SSD 1410 5 ph/s 10 10 13
EXAFS (m=1000) XANES (m=100) 10s 1s 1s(E) 0.1s5s 50s(E) 1s 0.1s PF Quick XAFS * 14
[] on the fly XAFS QXAFS DMM/ ADC DMM/ ADC QXAFS * E t XAFS R. Frahm, Nucl. Instrum. Methods, A270 (1988) 578. 15
QXAFS ( rise time VFC DMM(PF)ADC(SP8) Bragg (QXAFSBL VFC Voltage to Frequency Converter DMM: Digital Multi-Meter ADC: Analog to Digital Converter 16
QXAFS XAFS XANES 17
XAFS @ PF DXAFS (NW2A) QXAFS (NW10A, 12C, 9C) ms s min hr Time
XANES Ni 8s/spectrum
Fitting Results (Ni O) stageni-o stageni-o (5.8 4) XANES
QXAFS trade off channel-cut 23
channel-cut Bragg 2d sin = n n n E = hc = 12398.52 [ev A] detune * D const. h const. channel-cut mono. h 2Dcos 1keV Si(111)D=10mm 2021keV 1516keV 1011keV 56keV 34keV 0.009 mm 0.021 mm 0.069 mm 0.513 mm 2.344 mm channel-cut 24
XAFS XAFS SPring-8 BL40XU X X X (2714 mm) PC T. Uruga et al., AIP Conf. Proc., 882, 914 (2007) Pt L III 25
XAFS BL40XU @ SPring-8 X XAFS I0 X X Pt L 3 XANES Pt 26
QEXAFS (NH 4 ) 2 Cr 2 O 7 Cr 2 O 3 20ms H. Bornebusch et al. J. Synchrotron Rad., 6, 209 (1999) 27
Dispersive XAFS (DXAFS) []X ns T. Matsushita and P. Phizackerley, JJAP 20, 2223 (1981). A.M. Flank, A. Fontaine, A. Jucha, M. Lemonnier and C. Williams, J. Phys. (Paris), 43, L315 (1982). 28
XAFS @ PF DXAFS (NW2A) QXAFS (NW10A, 12C, 9C) ms s min hr Time
DXAFS l p p: q R Bragg 1 1 p q 2 Rsin w ** l E Ecot sin lecot 1 R p wlsin p=30m, l=0.1m, Si(111) Cu K Br K q=0.33m, E=1.3keV, w=2.2cm q=0.22m, E=2.9keV, w=1.5cm Multi-Pole Wiggler NW2A1cm 30
NW2A Tapered undulator u = 4cm, N = 90 periods high emittance S. Yamamoto et al., AIP Conf. Proc., 705, (2004). 31
beamline and DXAFS system: NW2A in situ reaction cell slit Water cooled Curved crystal (Bragg type) slit NW2 Sample Driver mirror Tapered undulator u 4cm *90 0.8T PF-AR ring 3 mirrors vertical focus, higher order red. Bremsstrahlung Stepping Motor Controller trigger Synchronize the gas inlet and data-taking Photodiode array or CCD detector ***** Detector Driver ADC PC 32
DXAFS equipment: NW2A sample cell polychromator PDA PDA In situ cell Curved crystal gas cells 33
DXAFS system Bragg Si(111), Si(311) etc. Laue E Si(311), Si(511) etc. E
Bragg case & Laue case Si(311) Rh 23.2keV a): DXAFS*, Laue, :PDA(S3901-512N,2.4 ev/ch) b): DXAFS*,Laue,:PDA(S3904-1024F/CsI, 1.1 ev/ch) c): DXAFS*,Bragg, PDA(S3904-1024F/CsI, 1.1 ev/ch) *:DXAFS,NW2, 2.0mrad, : 6x0.8 mm, Gap:25 : 30 m :Si(311), :260mm(Bragg), t Laue case Bragg case step scan 480mm(Laue) PDA 21500mm R:3000mm(Bragg), R:900(Laue) Rh-k edge (23.2 kev) E = 1844eV d): Conventional XAFS(BL-10B), Bragg, Rh k edge e): DXAFS(Spring-8),:CCD(1.6 ev/ch) :Si(422), : 48m :500mm PDA1140mm R:1000mm Pd-k edge (24.3 kev) E=1056 ev) f): Conventional XAFS (BL-10B), Bragg, Pd k edge t Energy / ev Energy / ev 2005/2/25 35
X X X PAD (XSTRIP / CCD (s) SPring-8ESRF Photo Diode Array 25/50m2.5mm1024/512ch) PDA PDA t=2ms 36
37
Energy resolution Pt LIIL II DXAFS Pt LIIIL III DXAFS Usual XAFS t Usual XAFS t Si(311) Si(111) E / ev E / ev DXAFS gives sufficient energy resolution 38
Dispersive and usual XAFS spectra A1: usual XAFS A2: DXAFS well prepared sample 60ms Pt/MCM-41 21 min 2100 times k 3 (k) B1: usual XAFS B2: DXAFS 21 min Non-uniform sample 60ms k/10 nm -1 DXAFS requires highly uniform sample. X-rays of different energies pass different sample position. 39
thickness effect like phenomenon knife-edge test cf.) M. Hagelstein, et al., J. Synchrotron Rad., 5,, 753 (1998) 40
DXAFS A(d) B(Pt-H) t Ratio of species A B t / s Energy / ev t / s E/ ev 900 ms 41 8
DXAFS 1.0 0.9 FT Pd(0)-O Pd(0)-Pd(0) Pd(II) Pd(II) Pd ln(i 0 /I) 0.8 0.7 0.6 0.5 24.30 24.35 24.4 20.6 kpa 673 K E / kev 24.45 t / s R / 10 2 pm PdO PdO Pd Pd(II)-O PdO10
43 probe probe pump probe probe pump pump SR SR SR SR SR SR XAFS (QXAFSDXAFS) SR mss XAFS NW2AXAFS SR SR pump( probe( SR pump( probe( SR pump( probe( SR pump( probe( SR 2ns 1.26s 1.26s
XSTRIP 44
DXAFSQXAFS DXAFS ns Quick XAFS XAFS XANES 20ms 45
DXAFSQXAFS DXAFS Quick XAFS E E k k E E QXAFS k 46
QXAFSDXAFS Fe(0)FeO1 DXAFS QXAFS 47
QXAFSDXAFSXAFS Quick XAFS step-scan DXAFS 48
15m/s 10m930m XAFS 15m250m S. Saigo et al., Biochim. Biophys. Acta, 1202 (1993) 99. D. J. Thiel et al., Nature, 362 (1993) 40. 49
(flow, batch) 50
BL-12C11 Ge K 30 20 GeBN k 3 /A 3 10 0 20 5 10 k/a -1 15 20 XAFS 51
hand press for powdery samples For solid-gas reactions, ex. catalytic reaction 1. keep enough gas diffusion into sample 2. high degree of sample homogeneity 3. high temperature, ex. 1000 K 4. support pellet with tube OD 10ID 7 52
gas diffusion into pellet Chemisorption measurements in a glass cell. H 2 adsorption isotherm at 298 K Torr blank powder Hand-pressed sample no difference between powder and hand-pressed samples. t / s 53
He, N 2, Ar etc 200 ml/min 200 ml/min 2 L/min 54
XAFSFlow Chromel-Almel thermocouple (C) heater catalyst [I] (E) Cu gasket ring ring cell volume dead volume < 1mL <400W)1000 gas(d) kapton window reference [I0] (F) gas pin (H) *** 10 mm 55
Pt in-situ CZ support Normalized Peak Height 1.9 1.7 1.5 1.3 1.1 Pt particle size: 7 nm 3% H 2 /He(60sec) 20% O 2 /He(60sec) 600ºC I I 0 500 1000 1500 2000 Time (sec) 30 sec 5 nm 1500 sec 3 nm ESRF ID-24 PF 56
Batch XAFS ( ) 200 ml 24 mm 60 mm V cut 124 76 water Vcut Heater 125.5 T = R.T.~800 * P= 10-5 ~ 900 Torr 24 57 12
XAFS ** 58
XAFS QXAFS QXAFS, DXAFS DXAFS, QXAFS ultrafast (t<ps) pump-probe 59
60
XAFS XAFS
a. (1) 62
Kr 20 kpakr K edge. 10 ms. t > 10 ms.
IR MSGC TR-XAFS 64
* 65
Sample temp./ Flow Power/w 300 250 200 150 100 50 1000 324W T.C. reading/ 200 400 600 800 T.C. reading/ 1000 : 0.3mA 660W(800) 300W (1000) * 66
DXAFS Pixel Array Detector XSTRIP Ge QXAFS 67
operand QXAFSDXAFS XAFS XAFS 68
PF KEK Proc., 2004-16 (2005). XAFSKEK Proc., 2008-5 (2008). 69