Mirrors and Multilayers
T. Matsushita
Photon FactoryHigh Energy Accelerator Research Organization

outline
Mirrors(1) role of mirrors(2) refractive index andreflection of X-rays(3) mirror materials andmirror coatings(4) surface polishing andcharacterization(5) curved mirrors(6) transmission mirror(7) heat load and coolingMultilayers(1) structure and X-ray
reflectivity(2) fabrication(3) characterization(4) graded multilayers(5) applications

Refractive index
For X-rays, refractive index isslightly smaller than unity.

n = 1 − δ + iβ

for E ∝ exp( +i (ωt − kr ))( n = 1 − δ − iβforE ∝ exp( − i ( ω t − kr )) )f1

n a re λ 2
β =
f2
2π

n a re λ 2δ =2πna: atomic density
f1=f0+f’

re =

f2=f”

f0 : atomic scattering factor
f’ and f”: real and imaginaryparts of anomalous dispersion
terrm
For forward scattering, f0=Ze2
4 πε 0 mc

2

Refer to Chap. 3 of “soft X-rays and extreme
ultraviolet radiation” by D. Attwood,
Cambridge Univ. Press, 1999

: (classical electron radius)δ x 105

β x 107

Si

0.488

0.744

Ge

0.908

2.33

Quartz

0.555

0.467

Pt

3.26

20.7

Au

2.96

19.5

Interaction
Interaction ofof x-rays
x-rays with
with mattermatter

ESRF
Experimental data

Asymptotic behaviour for E > E(K):f1 ≈ const

f2 ≈ 1 E 2

δ ≈1 E2

β ≈1 E4
δ≈ E2
βHigh energy applications !

Ch. Morawe – SPring-8 11.09.07

Snell’s lawcos( θ 2 )n1=cos( θ 1 )n2n1cos(θ1 ) = 1
ifn2

cos(θ 2 ) = 1

n2 < n1θ2 = 0

total external reflection

n1 = 1 in vacuum

θc =cos( θ 1 ) = 1 −2δ ≈ 1 ~ 20 mrad

θ122

= n2 = 1 − δ

For 10 keV
δ x 105θc (degree)

Si

0.488

0.179

Ge

0.908

0.244

Quartz

0.555

0.191

Pt

3.26

0.463

Au

2.96

0.441
L. G. Parratt, Phys. Rev.95 359 (1954)

Reflection
Reflection andand refraction
refraction

ESRF

Fresnel formulae for reflection and transmission amplitudes
rσ =n1 sin θ1 − n2 sin θ 2
n1 sin θ1 + n2 sin θ 2rπ =n1 sin θ 2 − n2 sin θ1
n1 sin θ 2 + n2 sin θ1tσ =2n1 sin θ1
n1 sin θ1 + n2 sin θ 2tπ =2n1 sin θ 2
n1 sin θ 2 + n2 sin θ1n2 < n1

Reflectivity amplitude as a function of external angle of incidence θ (vacuum)n1 − cos 2 θ − n2 − cos 2 θ
2

rσ =

2

n1 − cos θ + n2 − cos θ
2

2

2

2

n1 n2 n2 − cos 2 θ − n2 n1 n1 − cos 2 θ2rπ =n1 n2 n2 − cos 2 θ + n2 n1 n1 − cos 2 θ2Including graded interfaces (Gaussian density gradient, phase shift)−

8π 2

r = rideal ⋅ e λ2n12 − cos 2 θ2

n2 2 − cos 2 θ σ 2

Ch. Morawe – SPring-8 11.09.07

2

Reflectivity formula
E = 10 keV(θ − A ) 2 + B 2
R =(θ + A ) 2 + B 2
A=( a 2 + b 2 )1 / 2 + a2

B=( a 2 + b 2 )1 / 2 − a2a = θ 2 − θc = θ 2 − 2δ2

q = 4π

Si

Pt
σ=0
σ=1nm

σ=0
σ=1nm

b = 2 βsin( θ )E = 10 keVλFor q>>qc

Si

R∝

1

q4

H. Compton and S. K. Allison, X-Rays in
Theory and Experiment (D. Van Nostrand
Company, Inc., New York, 1935),

CXRO_ALS“X-ray Ingteractions with Matter”
http://henke.lbl.gov/optical_constants/

Reflectivity
curve
A total reflection mirror
works as a low-pass energy
filter. The cut-off energy canbe controlled by selecting
the material and theglancing angle.

Influence of absorption
edges sometimes appear in
the reflectivity curve.

From Uruga & Nomura, Hoshako(放射光) 2006 vol.19
No.4 pp.248-257, Fig.3

Requisites for mirror materials(1) Can be polished to a smooth and accurate surface
figure.
(2) Large material available. (~1.4 m long mirror presently
used)(3) Mechanically hard, Radiation resistive(4) Good thermal conductivity, low thermal dilation constant(5) No (low) gas emission under X-ray irradiation(6) Can be bent.
(7) Reasonable cost (material itself and fabrication)

Important parameters• Surface figure
flat, cylindrical, elliptic, parabolic, spherical, toroidal,
ellipsoidal, paraboloidal,---• Roughness
root-mean-square roughness ~0.1 nm• Slope error
root-mean-square slope ~0.5 μrad
• Thermal property
thermal conductivity
dilation constant• Absorption edges X-ray absorption

Materials for mirrors
SiliconZerodurFused silica
GlidCop (alumina
dispersion strengthened
copper alloys )Cu with electroless Ni
layer
Silicon Carbide (CVD)

Materials for mirror coating
Desired critical energy with a given
glancing angle
Retain smooth surface
No absorption edges desirable in therequired energy range
Au, Pt, Rh, Ni, Pd, Ru
θ = 3.3 mrad
Si

Rh/Si

Pt/Si
100 nmcoatingCoating of mirrors(Rh coating on silicon )30 nm

100 nm

50 nm

300 nmFabrication of mirrors• Grinding• Diamond turning• Lapping• polishing

Advanced Polishimg Technique (Elastic Emission Machining)

15

Ultra-fine particles aresupplied to the work
surface by ultrapure
water flow.

In EEM, chemical
reaction between solid
surfaces is utilized.
Ultrafine powder
particles having
reactivity to the work
surface are employed.

Atom removal occurs
selectively at the
topmost site of thework surface.
K. Yamauchi, et al.
Rev. Sci. Instrum., 73, (2002), pp. 4028-4033

P-V 1.603 nm
RMS 0.183 nm

nm
4

P-V 0.769 nm
RMS
0.087
nm

P-V 0.910 nm
RMS 0.100 nm

nm

2
0
50
0 40
0 30
nm
0 20
0 100

0 0

nm
50
40 0
30 0
20 0
100 0

Pre-machined surface

4
2

0
50
0 40
0
nm 30
0 20
0 10
0

0

50
40 0
30 0 nm
20 0
10 0
0 0

EEM surface （Removal depth:2nm） EEM surface （Removal depth:8nm）

Typical figuring properties using EEM

16Residual figure error (nm)20Prefigured profile
After 1st. figuring
After 2nd. figuring
Finished profile

15

10

5

0

-5
0

20

40

60

80

100

Position (mm)H. Mimura et al.,Rev. Sci. Instrum., 76, 045102 (2005).
K. Yamauchi et al., Rev. Sci. Instrum., 74 (5), 2894-2898 (2003).

K. Yamauchi et al., Rev. Sci. Instrum., 74 (5), 2894-2898 (2003).

Characterization of mirrors(surface roughness and figure)
Fizeau interferometer

Michelson interferometer
Twyman-Green interferometer(mirror: rotatable, point source)

Stitching interferometry

Atomic Force Microscopy
Stylus measurement

Characterization of mirrors(slope errors)• Long Trace Profiler“Results o f x-ray mirror round robin metrology measurements
at the APS,
ESRF, and SPring-8 optical metrology laboratories”
L. Assoufid, A. Rommeveaux, H. Ohashi, K. Yamauchi, H.
Mimura, J. Qian,O. Hignette, T. Ishikawa, C. Morawe, A.
Macrander, A. Khounsary, S. Goto
SPIE Conference on Optics and Photonics, San Diego: SPIE
Proc. 5921-21,
129 (2005).

Characterization of mirrors (slope errors)
Surface Gradient Integrated ProfilerZ

The light vector to P1

The normal vector in themeasuring point P1(nｘ ,n ｙ ,n ｚ )P

１

Y. Higashi et. al. , Proc. SPIE,OPTICS&PHOTONICS,
Advances in Metrology for X-Ray
and EUV Optics, 5921-07, San
Diego, CA, USA, 31 July-4
August, (2005)

Mirror surface
Detector D0

P０φθ
The light vector to
the first measuring pointordetectaotointring pusaXemrom a L
f
e
c
n
Dista
Parameters of the mirror
Substrate material

Basic Principle

CZ(111)Si single crystal

Surface coating

Pt

Effective mirror size

100 mm

In longitudinal direction

The normal vectors at each points on the surface aredetermined by making the incident light beam on the mirror
surface and the reflected beam at that point coincide.

Length of ellipse

500.075 m

Breadth of ellipse

44.7 mm

Differential surface profile between RADSI and present instrument
6

Surface gradient at each point is calculated from thenormal vector and the surface profile is obtained byintegrating the gradients.

Residual (nm)

4

50 mm

2

4-lines(0.83mm pitch)

0-2

100 mm

-4
-6
0

20

40

60

Position (mm)

80

100

At-wavelength phase-retrieval interferometry

21

Yellow: known
Incident Slit

Red: unknown

Focal point(z),φ33(z)II33(x3 ),z
z

I1(z),φ1(z)I2(x),φ2(x)xxIntensity (arb. unit)

1.0

0.5

0.0
-100 -80 -60 -40 -20 0 20 40 60 80 100
Position (nm)A strategy to fabricate KB mirrors for 10 nm hard X-rays focusing,
K. Yamauchi, X-Ray Optics: A Roadmap for the Next 10 Years
A one-day (August 1, 2005) Workshop at SPIE’s Optics & Photonics 2005 San Diego, California USA

Phase retrieval properties
I f = I fexp

1.0
0.0

-1.0

Fresnel-Kirchhoff
Diffraction Integral

-2.0
0

20

40
60
Position (mm)80

Wavefront errors

1.2
1.0
0.8
0.6
0.4
0.2
0.0
-100

Measured
profileIteration:0
profile-50050Position (nm)100

Intensity profiles

Iteration 10

Mirror surface
Restraint
condition

φm = φ p

Inverse projection

Virtual arc

On focal plane

2.0
Phase error (rad)Fresnel-Kirchhoff
Diffraction Integral

100

Actual profile

Recovered profile

1.0
0.0

-1.0
-2.0

Intensity is changed to experimental value.

0

Phase is kept to be recovered value.

20

40
60
Position (mm)

80

-50

0
50
Position (nm)100

Intensity profiles

2.0

Actual profile

Recovered profile

1.0
0.0

-1.0
-2.0

H. Yumoto et al.,
Review of Scientific Instruments 77, 063712 (2006).

Measured
profileRecoveredprofileIteration 1000

Phase error (rad)Phase is kept to be recovered value.

100

1.2
1.0
0.8
0.6
0.4
0.2
0.0
-100

Wavefront errors

On mirror surface
Intensity is changed to theoretical value.

Intensity (arb. unit)

X-ray

Initial profile

0

20

40
60
Position (mm)Wavefront errors

80

100

Intensity (arb. unit)

Restraint
condition

Phase error (rad)Focal plane

Actual Profile

Intensity (arb. unit)

2.0

22

1.2
1.0
0.8
0.6
0.4
0.2
0.0
-100

Measured
profileRecoveredprofile-50050Position (nm)Intensity profiles

100curved mirrors (focusing, collimating)
Cylindrical mirror

1 1
2
+ =
p q Rsin(θ )P=30 m, θ = 0.3°, R=1,000 m, q = 2.87 m
R=100 m , q = 0.26 m
Elliptic mirror

x2
a

2

+

y2
b

2

=1

a = 15.5 m, b = 0.03 m, 60 cm long mirror at 30 m from the source,θ ~0.28°- 0.37°, q = 1m

Bending mechanisms

bent-cylinder, toroidal mirror
2 pq
R1 =
( p + q ) sin(θ )

R2 =

R1 2
sin 2 θbent conical mirror– approximation to paraboloidal mirror Nomura,M. and Koyama, A.,
J. Synchrotron Rad., 6, 182(1999).

Kirkpatric-Baez (KB) optics for nanometer focusing
P. Kirkpatrick, A.V. Baez, J. Opt. Soc. Am. 38, 766 (1948)

Spring-8/Osaka KB development

1

Intensity(arb.units)• Static and figured Si substrates• Plasma Chemical Vapour Machining (PCVM)• Elastic Emission Machining (EEM)• Pt coating + thickness correction• Focal spots below 30 nm• Aiming less than 10 nm using multilayers

1.2

1 km beamline
E = 15keV

0.8

25nm

0.6

0.4

0.2

[23] H. Mimura et al,Jpn. J. Appl. Phys. Part 2 44, 18539 (2005)

0
-200

-100

0
Position(nm)

100

200

Transmition mirror: a high-pass energy filter
Silicon nitride transmission X-ray
mirrors
Cornaby and D. H. Bilderback
J. Synchrotron Rad. 15, 371-373(2008).

RT
SiN 300 nm
thickHeat load on and cooling of a mirror
Heat load: 86 W, 0.13W/mm2
Glancing angle: 1.5°Twater=25℃
temperature

deformation

Multilayers

X-rayX-ray multilayer
multilayer reflectivity
reflectivity

ESRF

Recursive calculation of Fresnel coefficients and propagation• Parratt formalism (widely used in x-ray optics) [8]Principle• Start at semi-infinite substrate surface (no reflection from back side)• Recursive construction of amplitudes and phases from layer to layer
⎤
+f
4 ⎡r
rn −1,n = an −1 ⋅ ⎢ n ,n +1 n −1,n ⎥⎢⎣ rn ,n +1 f n −1,n + 1⎥⎦

fn-1,n: Fresnel coefficients
En: Electric field at centre of layer n
tn: Thickness of layer nR

rn ,n +1 = anan = e

2

En
En

π
λ

−i ⋅t n nn 2 − n0 2 cos 2 θ

R = r0,1

2

Ch. Morawe – SPring-8 11.09.07

SubstrateX-rayX-ray multilayer
multilayer reflectivity
reflectivity

ESRF
Numerical calculations
Main features• Bragg peaks and fringes due to interference• Positions depend on E and Λ• Intensities depend on Δρ, N, σ…
Corrected Bragg equationm ⋅ λ = 2 ⋅ Λ ⋅ n2 − n1 cos 2 θ
22

For θ >> θC →m ⋅ λ ≈ 2 ⋅ Λ ⋅ sin θ

q

q

A
B

L
L*sinq

Ch. Morawe – SPring-8 11.09.07

ESRF

X-ray
X-ray multilayer
multilayer design
designMaterials choice – Basic rules:
1.
2.
3.
4.

Select low-Z spacer material with lowest absorption (βspacer)
Select high-Z absorber material with highest reflectivity with spacer (δabs – δspacer)
In case of multiple choices select high-Z material with lowest absorption (βabs)
Make sure that both materials can form stable and sharp interfaces (lower d-spacing limit)

Computational search algorithms••

Soft X-rays: A.E. Rosenbluth (1988)
Hard X-rays: K. Vestli (1995)[9] K. Vestli, E. Ziegler, Rev. Sci. Instr. 67, 3356 (1996)

Ch. Morawe – SPring-8 11.09.07

SiC/CMo/Si

AtomicnumberDensity(g/cm3)

C

6

2.26

Si

14

2.33

SiC

-

3.2

Mo

42

10.22

W

74

19.35

W/C

ESRF

X-ray
X-ray multilayer
multilayer design
designPeriod number N:
Peak versus integrated reflectivity:• Rpeak increases with N up to extinction• ΔE/E decreases ~ 1/N in kinematical range• Rint is maximum before extinction
High and low resolution MLs
Optimize N according to needs !

Ch. Morawe – SPring-8 11.09.07

W/C multilayer Γ=tW/Λ
Γ=0.1

Γ=0.5

Γ=0.3

Γ=0.7

Γ=0.4

Γ=0.9

Effect of interlayer diffusion
C/W Λ=6.9 nm Γ=0.4
0 nm

0.3 nm

0.6 nm

ESRF

X-ray
X-ray multilayer
multilayer fabrication
fabrication

Deposition
techniques
Thermal evaporation

VacuumParticle energy

Deposition rate

Deposition area

HV (UHV)

Low

Low

Small

E-beam evaporation

UHV

Low

Low

Small

Magnetron sputtering

HV (+Gas)

High

High

Large

DECR sputtering

HV (+Gas)

High

Low

Medium

Ion beam sputtering

UHV (+Gas)

Very highHigh

MediumPulsed laser
deposition

HV

Very highHigh

Medium• Characteristics may vary depending on equipment and application• Magnetron sputtering most widely used for X-ray multilayer fabrication• Vacuum and purity important for EUV and soft X-rays• High particle energy favors very thin and uniform layers
Ch. Morawe – SPring-8 11.09.07

X-rayX-ray multilayer
multilayer fabrication
fabrication

ESRF
History
1923

KoeppeCd/Agelectrolysis

unstable

1930

Deubner

Au/Agelectrolysis

unstable1935

DumondAu/Cuthermal evaporation

1 week life time

1963

Dinklage Me/Mg

thermal evaporation

stable1972

Spiller

1976

Haelbich Me/C

thermal evaporation

XUV MLs

1978

BarbeeW/Cmagnetron sputtering

X-ray MLs

1983

Gaponov Me/C

pulsed laser deposition

X-ray/VUV MLs

Au/MgF2 thermal evaporation

Ch. Morawe – SPring-8 11.09.07

UV MLsX-rayX-ray multilayer
multilayer fabrication
fabrication

ESRF
Sputtering techniques

RF (insulators)

DC (conductors)

Ch. Morawe – SPring-8 11.09.07

ESRF

X-ray
X-ray multilayer
multilayer fabrication
fabrication

Large area coatings (uniform, gradient)• Relative motion source - substrate• Masking techniquesrrr r dr ′t (r ) = ∫ ϕ (r , r ′) rv(r ′)

Ch. Morawe – SPring-8 11.09.07

X-rayX-ray multilayer
multilayer fabrication
fabrication

ESRF

ESRF magnetron sputter deposition system
Loading bay
Escape area
Escape area
Load lock

Deposition zone

Mobile and modular assembly

Ch. Morawe – SPring-8 11.09.07

X-ray multilayer fabrication
Sputtering techniques (Ion beam sputtering at Tohoku Univ.)

targetshutter
substrate

TEM
Mo/Si
D = 6.9 nm
λ = 13.5 nm
φ = 5°TEM
Cr/Sc
D = 1.77 nm
λ = 3.1 nm
φ = 27.5°

X-rayX-ray multilayer
multilayer characterization
characterization

ESRF
X-ray reflectivity

Simulation of x-ray reflectivity
10

Vertical density profile

0

24

10

-1

10

-2

10

-3

10

[Ir/Al O ]

Í

-4

10

-5

10

-6

[Ir/Al O ]

20

3 10

3

2

Mass density [g/cm ]Reflectivity

ρ(Ir)
2

16

12

8

ρ(Al Ο )

4

0

0°

1°

2°

3°
Θ

4°

5°

3 10

6°

Ch. Morawe – SPring-8 11.09.07

0

2

3

5

10
15
20
Sample depth [nm]

ρ(Si)

25

ESRF

X-ray
X-ray multilayer
multilayer characterization
characterization

X-ray scattering• Access to atomic structure• Phase transitions• Coherence lengths• Superlattice formation[17] D.L Beke et al, Vacuum 50, 373 (1998)[16] S. Bajit et al, J. Appl. Phys. 90, 1017 (2001)

Ch. Morawe – SPring-8 11.09.07

ESRF

X-ray
X-ray multilayer
multilayer characterization
characterization

Transmission electron microscopy (TEM)[W/B4C]50• Fabrication errors• Roughness evolution• Crystallinity• Interface diffusion

Complementary to x-ray measurements !

R. Scholz, MPI Halle, Germany

Ch. Morawe – SPring-8 11.09.07

ESRF

X-ray
X-ray multilayer/mirror
multilayer/mirror characterization
characterization

Surface metrology• Atomic Force Microscopy (AFM)• Interferometry• Long Trace Profiler (LTP)• From nm to m scale• No depth information !
A. Rommeveaux, ESRF Optics Group

Ch. Morawe – SPring-8 11.09.07

ESRF

X-ray
X-ray multilayer
multilayer design
designAperiodic design:R

Goal: ML with particular reflectivity profile• R = R(θ) for E = const• R = R(E) for θ = const
E

Find vertical composition profileθ

Method:• Derive analytical expression for reflectivity• Do inversion to obtain 1st estimate for layer sequence• Apply fit algorithm to optimize the structure[12] I.V. Kozhevnikov et al, Nucl. Instr. And Meth. A 460, 424 (2001)

Ch. Morawe – SPring-8 11.09.07

ESRF

X-ray
X-ray multilayer
multilayer design
designExample:[13] Ch. Morawe et al, Nucl. Instr. And Meth. A 493, 189 (2002)• Ni/B4C structure• R(θ) = const over 20% bandwidth
Theoretical design

Ch. Morawe – SPring-8 11.09.07

Experimental result

ESRF

EnergyEnergy resolution
resolution ofof multilayers
multilayers

Ch. Morawe – SPring-8 11.09.07

Reflecting
Reflecting X-ray
X-ray optics
optics –– Overview
Overview

ESRF
0

10

E = 8 keV10

ESRF MLs

-1

-2

10

-3

10

-4

Traditional
ML's
Ge

111

Si

111

10

-5

Single Crystals
Be

10

Depth-graded ML'sR(peak) = 100%110

(Mirrors/Filters)

10

High-resolution ML's

Integrated reflectivity

forbidden area

-6

10

-6

10

-5

10

-4

-3

10

ΔΕ/Ε

Ch. Morawe – SPring-8 11.09.07

10

-2

-1

10

0

10

Laterally
Laterally gradedgraded multilayers
multilayers

ESRF

Surface curvature and beam divergence define lateral gradient dΛ /dx

Shape

ParabolicAngle θsin θ =

Ellipticp
2f

sin θ =

Flat

b
pq

sin θ =

s
f

p/2
q

p

f

Geometry

θ

Θ

f

b

d-spacing including refraction correction(modified Bragg equation)

Ch. Morawe – SPring-8 11.09.07

θ

Λ=

λ ⋅m
2 n 2 − cos 2 θsLaterally
Laterally gradedgraded multilayers
multilayers

ESRF• Divergent beam, focusing applications with curved substrates• Incidence angle variation → laterally graded multilayers• Additional depth gradient negligible (< 10-5)
Focus
q

Ideal

8

∇Z

p

7 Model6Λt [nm]

5∇X

SourceActive area

Exp

4
B4 C

3
2
1
0
-30

Elliptic case

W

-20

-10

0
x [cm]

10

Ch. Morawe – SPring-8 11.09.07

20

30

laterally graded multilayers••

Soft X-rays

Divergent beam, focusing applications with curved substrates
Angle of incidence variation → laterally graded multilayers

Thickness control by• Relative motion of source - substrate (in magnetron sputtering)• Moving shutter (for a large gradient)
Ion beam sputtering

small φ,small Dlarge φ,large D

DoubleDouble gradedgraded multilayers
multilayers

ESRF
Energy dispersion:
Bragg equation: E (θ ) =2 Λ n 2 ( E ) − cos 2 θb2
sin θ =p⋅q
2

Elliptic mirror:

E (q ) =h⋅cp + q = 2⋅ah⋅cb2
2Λ n ( E ) − 1 +(2a − q )q2

Dispersion “along ML mirror”

Ch. Morawe – SPring-8 11.09.07

ESRF

DoubleDouble gradedgraded multilayers
multilayers

Intensity profiles: (Kirkpatrick-Baez multilayer optics on ESRF BM05)
Experiment

Theory[14] Ch. Morawe, Ch. Borel, E. Ziegler, J-Ch. Peffen, Proc SPIE 5537, 115 (2004)

Ch. Morawe – SPring-8 11.09.07

ESRF

Applications
Applications

Synchrotron optics: Multilayer high flux monochromators• Two bounce optics• 100x larger bandwidth compared with Si(111)• Harmonics suppression due to refraction and filling factor• Radiation and heat load issues !

Ch. Morawe – SPring-8 11.09.07

Applications
Applications

ESRF
ESRF focusing experiment• Full undulator spectrum• Vertical line focus• Dynamical bender• Raw data 45 nm FWHM @ 100 μm aperture
Focus detection

Graded ML

Aperture slits

White beam

Dynamical bender[24] Ch. Morawe et al, Proc. SPIE 6317 (2006)

Ch. Morawe – SPring-8 11.09.07

Multilayer application –Telescope–
Rocket launched Cassegrain telescopeSun

Mo/Si multilayer coated
λ = 17.1 - 17.5 nm

David Attwood
Soft X-rays and extreme ultraviolet radiation – Principles and Applications –(Cambridge University Press 1999).

Multilayer application –Microscope–
Schwarzschild objective of a laboratory microscope
Mo/Si multilayer coated
λ = 13.5 nm

Transmission image of#1500 Cu mesh (50×)
Fragments of a
Zr membrane

Scale
214

CCD camera
EUV source
20

50 μm

SampleYamamoto and Yanagihara group, Tohoku Univ.

Multilayer phase plate

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

Application
Simultaneous measurement of X-ray reflectivity curve
Laterally d-graded multilayer on an elliptic surface
T. Matsushita et. al., 2008
0.42 °

focusing：

dispersion：laterally graded multilayer

elliptic substrate

X-ray energy (keV)

0.12

30

0.1

20

0.08

15

0.06

10

0.04

5

0.02

0

0

5

10

15

20

25

30

Beam position on detector (mm)

0
35

0

5

10

15

0

0.05

0.1

0.15

20

25

-1

10

Reflectivity

25

Resolution, ΔE/E

X-ray energy, E (keV)

1

-2

10

-3

10

-4

10

-5

10

-1

q (A )

0.2

0.25

30

Other issues• Brewster’s angle, p-polarization• Other advance surface polishing techniques• Influence of imperfections
lower reflectivity,
broader multilayer reflectivity curve,
diffuse scattering• Radiation damages• Standing waves

On-going developments• Mirror and multilayers for handling much
more coherent X-ray beamslope error < 0.1 μrad, roughness < 0.05 nm
fabrication and characterization• Nanometer focusing optics• Multilayers with shorter period• Stable mount, tables and support

Acknowledgements
Dr. C. Morawe, European Synchrotron Radiation Facility
Prof. Y. Yamauchi, Osaka Univ.
Dr. T. Mochizuki , SPring-8
Dr. T. Hatano, Tohoku Univ.
Prof. M. Nomura, Photon Factory
Dr. T. Uruga, SPring-8
Dr. Y. Higashi, KEK
Dr. M. Suzuki, SPring-8
Dr. Hirono, SPring-8
CXRO_ALS web site: “X-ray Ingteractions with Matter”
http://henke.lbl.gov/optical_constants