X-ray monochromators
T. Matsushita
Photon FactoryHigh Energy Accelerator Research Organization

outline
1.

Controlling X-ray beam properties and the roll of
crystal monochromators
2. Bragg diffraction by crystals
3. Dynamical diffraction
4. Double crystal monochromator
5. Heat load and cooling
6. Higher harmonics rejection
7. High resolution monochromators
8. Phase retarder and polarization conversion
9. Curved crystals
10. Other issues and future problems

Synchrotron Radiation - Basic Properties

Winick: Presentation at JASS02 Seminar
http://conference.kek.jp/JASS02/PDF_PPT/3_2_winick.
ppt

High flux and brightness
Pulsed time structure

Broad spectral range
Polarized (linear,
elliptical, circular)
Small source size
Partial coherenceHigh stability
HIGH VACUUMENVIRONMENT

Flux = # of photons in given Δλ/λsec, mrad θ
Brightness (Brilliance)=# of photons in given Δλ/λsec, mrad θ, mrad ϕ, mm2(a measure of concentration of the radiation)

Designing your experiment- X-ray optical consideration -UTProtein crystallography

EXAFS(Extended X-ray Absorption Fine Structure)CU2A03

1.5

CU7B03

1.9

μt

1.125

0.75

UT

1.5

1.1

0.7

0.375
8500

0.3
8940

8960

8980

9000

9020

E/eV

9000

9500

9040

E: ~4 keV - ~20 keV (~10 keV - ~50 keV)
Beam size: 1 mm x 10 mm – 1 μm2

4

1 10

E/eV

ΔE/E: ~10-4

λ : 0.7 Å ~ 3 Å (E : 18 keV ~4 keV)

9060

Δλ/λdegree(ΔE/E) : oscillation
10-3 ~10-4
180Angular divergence : 2 ~ 0.2 mrad
Beam spot size : 5 ~ 200 μm

Designing your experiment- X-ray optical consideration Small angle scattering

PF 15A (bending magnet)

Powder diffraction

Spring-8 BL02B (bending magnet)

E: 6keV- 20 keV

E: 10 keV – 35 keV

ΔE/E: 10-3

ΔE/E: ~10-4

Angular convergence:
0.1- 0.2 mrad (V)1- 2 mrad (H)Angular divergence:

Focal spot size:
0.3 mm (V) - 1.0 mm (H)

0.5 – 1 mrad
Beam size:
V: 0.1 ~ 0.5 mm
H: 1 ~ 3 mm

Controlling the X-ray beam properties by X-ray crystal monochromators
Energy, energy resolution

Spatial spread

Time structure

Angular divergenceintensity

polarization

Example of beamline structure@SPring-8
Optics hutch

Light source

Storage ringExperimental
hutch
Concrete shield

Front-end Optics and transport channel
Experimental hall

Double-crystal
monochromator

Undulator

Bending magnet &front-end

Crystal monochromators
Bragg’s law of difraction
2d (Å) sin(θ ) = nλ (Å) = n

12.4
E ( keV )d: Latiice (d)-spacing,θ: glancing angle,
λ: X-ray wavelength
10 keV : 1.24 Å,1Å
: 12.4 keV
Energy (wavelength) resolution

θ

θ
d

dsinθ

dsinθ

ΔE Δλ
=
= Δθ cot θ
λEHigher harmonics
E1 = 10 keV (n = 1)E2 = 20 keV (n = 2)E3 = 30 keV (n = 3)

E1,E2,E3, ・・・・

Lattice planes of silicona0 = 5.43095 Å

Top view[001]
d-spacing(400) : 1.3578 Ǻ
(111) : 3.1356 Ǻ(311) : 1.6375 Ǻ

[010]

a

(511) : 1.0452 ǺSide view
a

(400)
(111)

[100]

[011]

(311)

(511)

Energy range of SPring-8
standard monochromatore.g. For SPring-8 standard monochromator

2d sin(θ ) = nλPhoton energy (keV)Æ Reflection
Si 111 : d = 3.1356 Å
Si 311 : d = 1.6375 Å
Si 511 : d = 1.0452 Å…..
Æ Bragg angle
3～27°
Æ Energy range
4.4～110 keV

120

E = 12.4/(2d sinθ)100

Si 511 refl.

80

Si 311 refl.

60
40
20

Si 111 refl.
0

0

5

10
15
20
Bragg angle (deg)25

Photon energy (wavelength) can be selectedby crystal, net planes, and Bragg angle.

30

Preparation of crystal monochromator
No or less imperfections
dislocations
stacking faults
point defects (non-uniformly
distributed, striations, aggregations)

Courtesy of Sharan Instruments Co. Ltd.

X-ray diffraction by a single crystal
Kinematical diffraction

Dynamical diffraction(imperfect crystal,(nearly perfect crystal)Multiplescattering

small crystal)

Single scattering
X-rays are scatteredonly once in the
crystal.

Siliconstationary wave
field

Germanium
QuartzDiamondgallium arsenide

angle

angle

X-Ray Dynamical Diffraction
•
•
•

•
•

P. Ewald (1912, 1917):
dipoles in the crystal which are excited by the incident X-ray wave and radiate X-rays.
C. Darwin (1914): multiple reflection by lattice planes.
M. von Laue (1931) :continuous medium consisting of periodic dielectric constant.
Experimental proof: in 1960’s and 1970’s, big perfect crystals (silicon, germanium,etc) became available
Since late 1970’s, perfect crystals have been used as monochromators on
synchrotron beamlines.

Textbooks and reviews
B. W. Batterman and H. Cole, Rev. Mod. Phys. 36, 681 - 717 (1964)
Dynamical Diffraction of X Rays by Perfect Crystals
A. Authier, Dynamical Theory of X-Ray Diffraction, International Union of Crystallography
Monographs on Crystallography No. 11. Oxford: Oxford University Press, 2001
R. W. James: The Dynamical Theory of X-Ray Diffraction, in Solid State Physics (Seitz andTurnbull) vol.15 (1963), Academic Press
M. von Laue: Roentgenstrahlen Interferenzen , 1941

Laue case and Bragg case

K0

Kh

K0

Kh

n
n

Laue case

Bragg case

Reflectivity
reflectivity for Bragg case, no absorption, and thick crystal:

)

(

2

2
γ h Eh2R== W + W −1
γ 0 E0R =1(−1 ≤ W ≤ 1)(

R = W − W −1
2)

2

(W < −1)

Å Total reflection

χ 0r =

πmc2V

e 2λ2
2

πmc V

F0r

For symmetric Bragg case, sigma polarization:

W = {Δθ sin 2θ BK + χ 0 r }

1
0.8

1

χ hr

Darwin width Æ ΔW= 2

0.6

ω=

0.4
0.2

2 χ hrsin 2θ BK∝ Fh

Shift of Bragg angle due to refraction:

0
-5

-4

-3

-2

-1

0
W

1

Fhre−M(W > 1)

1.2

Reflectivity

χhr =

e2λ2

2

3

4

5

Δθ refraction = −χ 0r
sin 2θ BK

Silicon single crystal, E = 10 keV
Braqg angle(degree)hkl

ω(arc sec)ω(μrad)

111

11.403

5.476

26.55

220

18.836

3.984

19.32

311

22.246

2.273

11.02

400

27.167

2.495

12.10

422

34.001

1.886

9.142

333

36.379

1.228

5.952

440

40.22

1.543

7.479

χ0h on the web!!!
http://sergey.gmca.aps.anl.gov/x0h.html

For thick absorbing crystal in the Bragg-case (reflection geometry), thereflectivity is given by
R = L−
2

L2 − (1 + 4 κ 2 )
22

2

2

L − (W −1−g ) +4( gW − κ ) +W +g

κ =

2

χ hi
χhr

g=

χ 0i
χ hr

For thin absorbing crystal of the Laue-case (transmission geometry), thereflectivity is given by⎡exp( − μ t / γ ) ⎢ 2
RT =sin ( A 1 + W 2 ) + sinh 2(1 + W 2 ) ⎢⎣A = π k χ hr

⎤
⎥
2 ⎥
1+W ⎦

κA

t / γ

Intrinsic rocking curve for silicon
Based on the dynamical theory for perfect crystal
for thick crystal and absorption considered:
1

Reflectivity

0.8

333 refl.
30 keV

111 refl.
10 keVω =回折幅

2 χ hrsin 2θ BK

0.6

χhr =

0.4

πmc2V

Fhr e− M

χ0r
Δθrefraction= −sin2θBK

0.2
0
-100

e2λ2

-50

0
Δθ (μrad)50

Features:・Diffraction width (Darwin width) of 0.1～100 µrad
・Peak reflectivity of ~1 for low absorption case

100

χ0r =

e2λ2
2

πmc V

F0r

Angular divergence of sources anddiffraction width
3

10

2

FWHM (μrad)

SPring-8 bending
magnet1
σ r ≈ ≈ 60 μrad

Bending magnet

10

Undulator 1st
1

10

γ

Si 111 refl.
Si 311 refl.

0

Undulator (N= 140)

10

Si 511 refl.

σr ≈

-1

10

0

20

40
60
Photon energy (keV)80

1≈ 5 μradγ N

100Divergence of undulator radiation is the same order as
diffraction width of low order reflection.

Energy resolution
ΔE= cot θ B ω 2 + Δθ 2
E
(1) ω

Δλ

ΔE/E=10-5～10-3

ω: intrinsic angular width of diffraction

Δθ: angular divergence of X-ray beam
λ-1

λ0

2d sin(θ0) = λ0

λ12d sin(θ-1) = λ-1
2d sin(θ1) = λ1

For Si 111, ω = 2.66 x 10-5 rad at 10 keV
ΔE/E = ω cotθ = 2.66 x 10-5 x cot(11.4°) = 1.32 x 10-4(2) Δθ

source-to-slit distance = 30 m
slit width = 1 mm

Δθ = 3.3 x 10-5
Si 111, 10 keV: θ = 11.4°

ΔE/E = Δθ cotθ = 1.6 x 10-4

Energy resolution
ΔE= cot θ B Ω 2 + ω 2
E

Ω: divergence of source
ω: diffraction width-2

10

Bending magnet + Si 111 refl.
Bending magnet + Si 311 refl.

-3

10

ΔE/E

Bending magnet + Si 511 refl.

-4

10

Undulator 1st + Si 111 refl.

-5

10

0

20

40
60
80
Photon energy (keV)

100

Using slit, collimator mirror,.. we can reduce Ωeff,

ΔE/E=10-5～10-3

SPring-8 standard DCM

3º < θB < 27ºOffset h= 30 mm

Adjustment stages
for undulator beamline DCM
Sub-micron, sub-μrad control

Goniometer and angle accuracy
Energy scan (Si 111 d = 3.119478Å)
E0: 10.000 keV θ = 11.46246°
E1: 10.001 keV θ = 11.46130°

Δθ = 0.001162°= 4.18 arc s = 20.3 μrad

0.2 arc s / step (1 μrad / step)
Courtesy of Kohzu Seiki Co. Ltd.

Double crystal monochromator• Constant beam direction• beam height changes
slightly when E is
h = 2 g cos(θ )changed.
• Two crystals should beparallel to each otherwithin sub-arc-seconds.
• Tail intensity falls off
rapidly.

hgAlignment of a double crystal monochromator(1) Parallelity in the scattering plane: sub-μrad(2) Parallelity normal to the scattering plane: ~10-3 - 10-4 radΔθ = −(3) Parallelity to the rotating axis :

δ

δ

φ2
2

tanθ

ψ: 10-3 – 10-4

δ = 2ψ sin θCourtesy of Kohzu Seiki Co. Ltd.

Stability and disturbances
Variation at the sample•••

Energy :0.1 eV for XAFS,
sub-meV for high resolution inelastic scattering
Intensity : less than 1 %.
Beam position: typically several tens ~ 1 μm

Source instability
Source size change, source position change, charge distribution change

Room temperature variation
Heat load by the radiation itself
Vibration
floor, cooling water, vacuum pumpFixed-exit DCM(1) θ 1+ translation + θ 2 link(2) θ + two translation link

2nd crystal

θ -stage

1st crystal

θ -stageh

1st crystal

2nd crystal
O
Exit beam
θB
θB B

A

y

y=

h
tan 2θ B

Translation stagezyz = OB =h2 cosθ B

OffsethθB

y = AB =h
2 sin θ B

( y 2 − h 2 / 4)( z 2 − h 2 / 4) = h 4 / 16

A number of different schemes have beendeveloped to realize a fixed-exit beam.

Boomerang link type

Kirkland, NIM-A291 (1990)

h= 50 mm, θB= 5～85°

UVSOR BL 1A, BL 7A
Hiraya et al., RSI 66 (1995)

θB= 18.5～71.5°

Æ Difficulties for crystal cooling and multi-stage adjustment
Æ Low rigidityθ + two translation (KEK-PF)

PF BL-4C..

h= 25 mm, θB= 5～70°

Matsushita et al., NIM A246 (1986)

Two cams for two translation-stages
Rotation center at 2nd crystal

Heat load on 1st Crystal
Heat load on the mochromator 1st crystal:Æ For SPring-8 bending magnet source
100 W & 1 W/mm2
Æ For SPring-8 standard undulator source~500 W & ~ 500 W/mm2
cf.

Hot plateCPU: ~ 0.02 W/mm2: ~ 0.3 W/mm2

Crystal cooling
Why crystal cooling？
Qin (Heat load by SR) = Qout (Cooling + Radiation,..)Æ with temperature rise ΔT
Æ αΔT = Δd (d-spacing change)
α: thermal expansion coefficientor Æ Δθ (bump of lattice due to heat load)
Miss-matching between 1st and 2nd crystals occurs:Æ Thermal drift, Loss of intensity, Broadening of beam, loss of brightness
Æ Melting or limit of thermal strain Æ Broken !
Qin

Radiation & convection
T1
Heat conduction in crystal

CrystalT0

熱伝達

Coolant/holder

Heat transfer
to coolant/holder

Solution for crystal cooling
We must consider:
Thermal expansion of crystal: α,Thermal conductivity in crystal: κ,
Heat transfer to coolant and crystal holder.
Solutions:(S-1) κ/α Æ Larger(S-2) Large contact area between crystal and coolant/holderÆ larger(S-3) Irradiation area Æ Larger, and power density Æ smaller

Figure of merit
SiliconSiliconDiamond

300 K

80 K

300 K

300 K

κ (W/m/K) 150

1000

2000

401

α (1/K)-5x10-7

1x10-616.5x10-6

2000

2000

24

2.5x10-6

κ / α x106 60

Figure of merit of cooling:
Good for silicon (80 k) and diamond (300 K)

CopperFor SPring-8 case
Bending magnet beamline
Power and density : ～ 100 W, ～1 W/mm2 @40 m
Method:Æ Direct cooling with fin crystal

Å S-2

Undulator beamline(Linear undulator, N= 140, λu= 32 mm)
Power and density : ～500 W , ～500 W/mm2 @40 m
Methods:
Æ Direct cooling of silicon pin-post crystal
Å S-2+ Rotated inclined geometry (Æ10 W/mm2) Å S-3
Æ or Cryogenic cooling using LN2 circulation
Å S-1
Æ or Indirect cooling of IIa diamond crystal
Å S-1

Direct cooling with fin crystal

Fins with
Inserted metal

Applied to bending magnet beamline

Performance of fin crystal (1)Si 111 refl.
Si 333 refl.

Intensity (arb. units)

1.2
1

Uniformity
0.3%

0.8
0.6

hν= 25 keV
Si 111 refl.

0.4
0.2

Ring current= 1 mA

0
-40

-30

-20

-10

0

10

20

30

40

Horizontal position (mm)Mechanical deformation removed

Direct cooling with fin crystal
Improvement of fin-cooling crystal
Reduce radiation damage of rubber O-ring

Au-Si eutectic
bondingDirect cooling with fin crystal
Reduce radiation damage of rubber O-ringSRPerformance of fin crystal (2)X-ray image for Si 311 refl.

θB= 5°, E = 43.4 keV
θB= 10°, E = 21.8 keV
θB= 20°, E = 11.1 keV
Slit: 3 mmV×40 mmH

Current status
・Practical use both (311) and (111) crystals
・2～4 sec. twist due to fabrication process must be reduced.
・No heat strain for (111) crystal at 12 keV photon
・Radiation damage of O-ring is improved by side-inlet．
・Durability test is under way.

Rocking curve width FWHM (µrad)

Performance of fin crystal (3)70E= 7 keV

60
50

E= 12.4 keV

4030

E= 18.9 keV

20
10
0
0

10

20

30

Slit width (mm)Si 111 refl.
Ring current= 100 mA

40

Direct cooling of silicon pin-post crystal+ Rotated inclined geometry
150 mmIrradiation area

Inclination angle β= 80°
Grazing angle down to 1° using φ-rotation
Irradiation area enlarged to x50, power density reduced to 1/50

Applied to undulator beamline

Structure of pin-post crystal
Top plate with pin-post is bonded to base plate (manifold)using Au-Si eutectic bonding.

Pin-post structure
0.2 mm 0.6 mm
0.2 mm

0.6 mm
0.5 mm0.35 mm

Water flow

Fine pins are fabricated to increase cooling efficiency.
Limitation of sandblast

DCM with pin-post crystal

DCM view from upstream

Inside DCM: Stages + pin-post crystal

Performance of pin-post crystal
80
Calculation

FWHM (µrad)

Meas. @BL41XU (2003)

60

40

20

0
0

5

10

15

20

25

30

Photon energy (keV)

Rocking curve widths agree well.
A rocking curve is obtained by rocking (rotating) the second crystal of the
double crystal arrangement and recording the diffracted intensity.

Cryogenic cooling
LN2 circulator with He refrigerator

Indirect side cooling

Applied to undulator beamline

Silicon, Liquid Nitrogen Cooling
465W, θ=6.9°25 W/mm2
Spring-8 undulator beamline
Temperature distribution

Deformation distribution

Coutecy of Dr. T. Mochizuki, Spring-8

Performance of pin-post coolingand cryogenic cooling
Heat load test (June 2000) up to 500 W, 500 W/mm2

Pin post Î

LN2 Î
Í LN2

Í Pin post

IIa diamond indirect cooling
Merit:- Good thermal properties Æ Capability of indirect cooling- Higher resolution (ÅÆ Less throughput (30～40% of Si))

Issues:- Perfection of crystal Æ HPHT IIa diamond (Sumitomo)…
Successive upgrade is crucial !
- Holding of crystal Æ X-ray topograph, Zygo
- Optimization of thermal contact Æ New process with In insert- Small crystal (< 10 mm□)
- Alignment: using CCD camera, PIN photodiode, thermocouple

IIa diamond crystal
Nearly perfect crystal using High Pressure High Temperature (HPHT)
synthesis is available in <001> growth direction.
To maximize the photon flux, 111 refl. in Bragg case is used.
Effective size of Diamond (111) is, however, small !
<001>

<001>

(111)

<111>

Seed

(100)

5 mm

Seed

Crystal handling is crucial:Æ Mounting without strain
Æ Alignment

5 mm

Crystal mounting
Thermal mounting method
Mechanical mounting with
SS plates and screws

Release the screws

Temperature increase to ~ 130 °C
Keep 30 min
Decrease to room temperature

Intensity (a.u.)

Topograph and rocking curve

Measured
Calculated

1

0.5

0
-10

0

Rotation angle (arcsec)

10

Diamond monochromator(SPring-8 BL39XU)SRCharacterization of
diamond monochromator
Photon flux (photons/s)

Photon flux
Diamond measured
Diamond calc.
Si measured

1014

Beam image

1013

1 mm
0

10
20
30
Photon energy (keV)40

ε = 3 nm. rad, Ib = 100 mA

Front-end slit aperture = 0.7 (v) x 1.0 (h) mm2
Low energy: 50~60% of Si DCM
High energy: Infinite size effect ?

Improvement of crystal growthand surface finish is needed.

Higher harmonics rejection- total reflection mirror  Substrate material
Si for white radiation
SiO2 for monochromatic beam

 Coating material
Pt, Rh, Ni,...
Depending on energy, reflectivity, absorption edges,..

 Glancing angle
2～10 mrad (For SPring-8 X-ray beamline)
Depending on energy, reflectivity, absorption edges,..

 Mirror length
400 mm～1 m (For SPring-8 X-ray beamline)
Depending on the beam size and glancing angle
e.g. 100 µrad×50 m/5 mrad= 1 m

Example of mirror reflectivity
1

Reflectivity

0.8
Rh, 2 mradPt, 2 mrad

0.6

0.4
Rh, 5 mrad

0.2

Pt, 5 mrad

0
0

10

20

30

40

Photon energy (keV)

Film thickness: 50 nm
Surface roughness: 1 nm

50

60

Higher harmonics rejection- Detuning of DCM -no detuningwith detuninge.g. Δθ = 12 μrad
Æ 70% of peak intensity for fundamental (111 refl. @ 10 keV)Æ 0.3% of peak for 3rd harmonics (333 refl. @30 keV)e.g. Δθ 2= 10 μrad Æ Angle change of exit beam = 2Δθ 2= 20 μrad
Beam position change of 0.2 mm @10 m from DCM.
We should recognize the beam position change by DCM detuning!

High resolution monochromator
double crystal arrangements and the DuMond diagramAsymmetric diffraction forhigh resolution monochromator

Extremely High-Resolution X-Ray
Monochromators

Channel-Cut

Asymmetric Channel-Cut

Original “Nested-Channel-Cut”, ~6meV@14.4 keV
Ishikawa et al., RSI (1992)

120µeV @ 14.4 keV
Yabashi et al., PRL (2001)

0.52meV@25.65keV
Alfred Q. R. Baron,a*
Yoshikazu Tanaka,b Daisuke
Baron
et al., JSR(2001)
Ishikawa,b Daigo
Miwa,bMakinaYabashia and Tetsuya
Ishikawaa,b J. Synchrotron Rad. (2001). 8, 1127-1130

Spherical Diced Crystal Energy Analyzer- meV resolution-ΔE= ω 2 + Δθ 2 cot θEWhen θ = 89.97°
cotθ ∼ 5.2 x 10-4
If

ω 2 + Δθ 2 ~ 10-3 -10-4

ΔE/E ~ 10-7 – 10-8
R=9.8 m Spherical Diced Crystal
AnalyzerPower Load Effects on Backscattering
Monochromator
Flat Crystal
Analyzer

Detector
VerticalTranslation~130 mW
Incident Beam
From Si (111) monoBackscattering Mono
At the (11 11 11)

Grazing
Incidence

1

NormalIncidence

0.8

0.6

0.4

0.2

0

-4

-2

0

Energy Offset (meV)24phase retarder, polarization conversion- transmission through a thin crystal -Concept of dispersion surfaces should be utilized to understand.

M. Suzuki and T. Hirono,Hoshako（放射光） Nov. 2006, Vo.19 No6, pp.444-453

Sagittal focusing
Bending mechanism
for SPring-8 sagittal focusing

Principle of sagittal
focusing

e.g. Sagittal
focusing images

Focal point

2nd crystal

1st crystal

r=

2 pq
sin θ
p+q

r: radius of 2nd crystal

50 mm
Si 311 refl.
40 keV
Source～Crystal=
36.5 mθ: Bragg angle
p: source ~ crystal distanceq: crystal ~ focal point distance

Applied for bending magnet beamline

Crystal～focal
point= 16.5 m

Dispersive X-ray Absorption Spectroscopy
T. Matsushita & R. P. Phizackerley:Jpn. J. Appl. Phys. 20, 2223-2228 (1981)
1980
R = 100~300 cm
EH-EL = ~ 1 keV

n = 1000
n = 100

n = 10n=1
Ni K-edget = 100 ps x n

稲田、丹羽、野村：放射光、20,242 (2007)

Multiwavelength Dispersive X-Ray Reflectometry

Q=4π sin(α)/λ~ E sin(α)
Q: 0.08~0.8 Å-1
Qmax/Qmin=10
Emax/Emin =10
Q(large)Q(small)λ(long)

R = 10~30 cm
EH - EL = 30 ~ 50 keV

λ(short)T. Matsushita et. al., Appl. Phys. Lett. 92, 024103(2008)

Other issues
•

•
•
•
•
•

Phase space analysis
position-angle (position-momentum) space
Extended Phase spaceposition-angle-wavelength spaceposition-angle-energy space
Ray tracing
Feedback control of the DCM
Compton scattering (heating of the 2nd crystal)Stress due to crystal mounting
Surface finish and residual stress layer••

Wide band-pass monochromators
Quick-scan monochromators•

Dispersion surface•

Future subjects• Smaller slope error, smaller roughness, smaller residual
stress• optics for handling more coherent X-rays• More higher resolution• Wide bandpass crystal monochromator• optics for handling more bright( intense) beam
• optics for handling extremely short pulses

Acknowledgements
Dr. S. Goto, Spring-8
Dr. T. Ishikawa, RIKEN/Spring-8
Dr. K. Hirano, Photon FactoryProf. H. Winick, SSRL
Mr. H. Kohzu, Kohzu Seiki Co. Ltd
Mr. Koizumi , Sharan Instruments Co. ltd
Dr. T. Mochizuki, Spring-8
Dr. M. Takata, RIKEN/Spring-8
Prof. Y. Amemiya, Univ. of Tokyo
Dr. M. Suzuki, Spring-8
Dr. T. Hirono, Spring-8