Introduction“X‐ray beamline looks complicated ?”Cheiron school 2013 , 28th Sep. 2013, SPring‐8
X‐ray beamline design Ⅱ

Storagering

Optics Engineeringfor x‐ray beamline design

inside shielding tunnel (front end )Haruhiko Ohashi
JASRI / SPring‐8
outside shielding tunnel (optics hutch )What function of each component ?

Light source(IDs/BM)

Key issues for the beamline design

X‐raybeamline

Front end (FE)Radiation
shield hutch

Light source

Key issues

Design components

Applications at the BL ( scientific strategy, concept )• End station( pressure, temperature,• Sample environment
magnetic field…)• Detector, data processing … ( automation )– Photon beam properties at sample
•
•
•
•
•
•

( Power )Human safety
EngineInterlocksystemBrake
Air‐bags

Machine protection
Radiator
Body• Protection from radiation hazard to health• Protection from radiation damage to instruments

Tailoring x‐rays（ Power control ）Mirrors– Utilities––––

User Interface

A vehicle

Steering wheel
Dashboard
Gear leverApplication( drive)

End station• Light source (ID, BM)
Photon energy, energy resolution• Monochromator,
higher order
You have to describe
beam parameters
forsuppression…
experiments.
Flux, flux density• Focusing devices… Optics (ex. mirror)
Sometimes these requests are competing.
Beam size
Stability• Polarizer…
↓ Beam position monitor( long , short term )Polarization• Window…
You have to assign
priorities
to the beam performance.
Spatial coherence• RFtiming, chopper…
Priority ?
Time resolution• Radiation shielding hutch …

– Human Safety & Machine protection

Monochromator

Transmission
Gear

2

3

Time schedule
Human resources
Available budget, space, technical level
Maintenance & lifetime of BL( hardware, applications )• Interlock system• Beam shutter…
•
•
•
•
•
•

Front end

Absorber, FE slit
Cooling method, cooling system
Selection of light sources ( power, angular dist.)
Electronics in hutch ( detector, controller … )Embrittlement (cable, tube )Contamination on optics• Electricity, water, air, network, control• Environments ( temperature, vibration… )Management of the beamline construction

4

Light source(IDs/BM)

Front end (FE)X‐raybeamline

XBPM

Radiation
shield hutch

Heat managementforhuman safety & machine protection↓
Front end
( FE )

Light source
Human safety
Heat management

InterlocksystemMachine protection

Beam position monitor

Monochromator
Tailoring x‐rays

Optical design

Mirrors( for example, mirrors )User Interface

DesignMetrology

Alignment

Today’s contents

Utilities
Application

Experimental station

6

5

Beamline components for safety

Beamline components for safety

Front end

78

SPring‐8 Tunnel

Schematic Layout inside the SPring‐8 Tunnel

Front end (15～18m)

Tunnel of the storage ring (1/16)

Front end (FE)(15～18m)

Why so long FE?

9

Key functions & components of FE(a) Shielding for human safety
Beam shutter (BS), collimator ( radiation shield )(b) Handling high heat load for safety Absorber, masks (to prevent BS from melting)(b’) Handling high heat load for optics
XY slit, filters ( to prevent optics from distorting )(c) Monitoring the x‐ray beam position
XBPM (x‐ray BPM ), SCM (screen monitor )(d) Protection of the ring vacuum
FCS (fast closing shutter ), Vacuum system

Standard
in‐vacuum undulator
Power density :500 kW/mrad2
Total power : 13 kW

10When we operate a main beam shutter (MBS), what happens ?
X‐ray

Absorber ( Abs )Beam shutter ( BS )to protect BS from heat load
A block of
33 kg
Move
is moved

to shield you against radiation

Move

Glidcop®
(copper that is dispersion‐strengthened
with ultra‐fine particles of aluminum oxide)

MBS ( = ABS + BS )Shielding wall

is opened,
beam reaches optics hutchthrough shield wall.
11

A block of
30～46 kg
is moved

the thermal conductivity
Heavy metal
not so high(alloy of tungsten)

After BS is fully opened, Abs is opened.
After Abs is fully closed, BS is closed.
The sequences are essential to keeping safety.

ABS and BS work on ways together
to protect us from radiation when we enter the hutch.

12

FE: “For users to take lion’s share”

Other key function is to handle high heat load for optics(a) Shielding for human safety(b) Handling high heat load for safety(b’) Handling high heat load for optics(c) Monitoring the x‐ray beam position(d) Protection of the ring vacuum

Beam shutter (BS), collimator ( radiation shield )Absorber, masks (to prevent BS from melting)
XY slit, filters ( to prevent optics from distorting )XBPM (x‐ray BPM ), SCM (screen monitor )FCS (fast closing shutter ), Vacuum system•••

Adding a spatial limitation to photon beam,
supplying only a good quality part around the central axis of ID
to transport optical system safely and stably.①Fixed Mask Aperture ②Pre Slit Aperture
322rad x 322rad

The size of XY slit is set to 1.05mm□．
XY slit is installed ～30m away from ID.

152rad③XY Slit Aperture
35rad x 35rad⓪②➀

Higherorder
These components cut off
the power to prevent
optics from distorting byheat load.

③

Someone may enlarge opening of XY slit to get more flux → You can NOT get it!

13

Slit : “Too much is as bad as too little”

1st harmonic
Flux Density

Power Density
Helical Mode Operation
at BL15XU 14

Handling Technology of high heat load

1st harmonic flux

How to manage
high heat load
by FE XY slit ?

SPring‐8 Standard In‐Vacuum Undulator : 13.7kW, 550kW/mrad2

at SPring‐8

Spatial distribution of power

29 kg

Y: 15urad = 0.5mm/30m
X: 40urad = 1.5mm/30m

29 kg

Incident angle
0.08 deg(1.5 /100 )to accept the power

15

16

Simulation: “better safe than sorry”

For instance, the distributions of temperature and stress of Be window at FE can be calculated
by FEA (finite element analysis ).

Key issues of FE design
1. There exists a category of the beamline front ends.
They have their proper functions, proper missions based on the principles
of human radiation safety, vacuum protection, heat‐load and radiation
damage protection of themselves.
They have to deal with every mode of ring operation and every mode ofbeamline activities.

2. Any troubles in one beamline should not make any
negative effect to the other beamlines.
3. Strongly required to be a reliable and stable system.
We have to adopt key technologies which are reliable, stable and fully
established as far as possible.

Higher the initial cost, the lower the running cost from thelong‐range cost‐conscious point of view.
18

17

Where is XBPM installed ?
XBPM is installed before any spatial limitation. You hardly find it.
It is quietly monitoring beam position at any time.

Monitoringstability of photon source↓
X‐ray beam position monitor( XBPM )Another monitor is installed
after spatial limitation.
It is useful to check the centerof XY slit. Usually it is retracted.

1920Structure of XBPM’s detector head

( Photo‐emission type )Fixed‐blade style XBPM‐ Four blades are placed in parallel to the beam axis to reduce heat load.
‐ CVD diamond is used because of excellent heat property
Electrons from each blade of Ti/Pt/Au on diamond emitted by outer side of photon beam
The horizontal or vertical positions computed by each current

X-ray

for SPring‐8 in‐vacuum undulator,etc.
(19 beamlines)

XBPM
XBPM
Surfacediamondis metalized.
for insertion
deviceof(ID)beamlinefor bending magnet (BM) beamline

XBPM is installed on stable stand and stages
22

21High stability of XBPMLong term stability of XBPM at BL47XU

As the stability is compared with other monitors outside wall,
the stability of XBPM for 3 hours and 23 hours are measured.

After 3 hours
V: 1.7 m H: 3.5 m (RMS)

Gaps is set at reference points (Minimum gaps).

After 23 hours
V: 4.7 m H: 3.2 m (RMS)All Gaps are set at reference points (Minimum gaps).

Stability of the XBPM is a few microns for a day

under the same conditions ( ID‐gap, filling patter & ring current).

23

24

ID‐Gap dependence of XBPM

Orbit correction using XBPM

Measured at BL47XU
with fixed‐blade style

Photo‐emission type
Reference point (Minimum gap )The beam
recoveredusing XBPM.
The beam lostat optics hutch.
Electron beam monitored
same orbit before.

Gap dependence:

A fixed point observation of XBPM is
helpful for a regular axis from ID.

～ 100m for Gap : 9.6 ~ 25 mm , ～300m for Gap : 9.6 ~ 50 mm
The position of the beam at optics hutch was fixed for changing ID gap.
25

26

Key issues of XBPM design

What does the XBPM tell us ?
ID‐Gap minimum

What does the XBPM tell us ?

for high power undulator radiation in SPring‐8

ID‐Gap fully opened

1. Dependence of ID gap, ring current, filling pattern
XBPM (photo‐emission type ) depends on these parameters.
2. High stability
XBPM has stability of microns for a day.
3. Resolution of x‐ray beam position‐ The resolution of micron order can be monitored.
Beam divergences are ~ 20 / 5 μrad ( hor. / ver. ), which correspond to
beam sizes of ~ 400 / 100 μm ( hor. / ver. ) at XBPM position (20 m from ID).

Origin of ID‐gap dependence of XBPM:

4. Withstand high heat Load
‐ Blade of diamondMax. power density is ~ 500 kW/mrad2. Metal will melt immediately.

‐XBPM of photo‐emission type has energy dependence.
Radiation from ID changes drastically, but not from BMs (backgrounds)‐ Backgrounds are asymmetric and usually offset.
1st harmonic:
6 ~ 18 keV,
Background: < several keV near beam axis of ID

5. Fast Response‐ Response time of < 1 msec needs for high frequency diagnostic.
‐ Simultaneous diagnostic over beamlines is important.

XBPM depends on ID‐gap, filling pattern & ring current.
The results of XBPM can be compared with the same condition.

27

Ref. of XBPM : for example, H. Aoyagi et al., “High‐speed and simultaneous photon beamdiagnostic system using optical cables at SPring‐8”, AIP Conf.Proc.705‐593 (2004).

28

Intensity (a.u.)

300

The functions of x‐ray mirrors

200

25nm
100

0
0.0

0.2

0.4

Tailoring x‐rays
to application↓
X‐ray mirrors
design, errors, metrology& alignment

0.6

0.8

Position (m)
No errors• Deflecting• Low pass filter• Focusing• Collimating• Separation from γ‐ray• Branch / switch beamline• Higher order suppression• Micro‐ / nano‐ probe• Imaging• Energy resolution
w. multilayer or crystal mono.

30

29

Intensity (a.u.)

300

Design parameters of x‐ray mirror

200

25nm

Requirement

100

0
0.0

0.2

0.4

the beam properties both of incident and reflected x‐rays

Tailoring x‐rays
to application↓
X‐ray mirrors
design, errors, metrology& alignment

0.6( size, angular divergence / convergence, direction, energy region, power… )0.8

Position (m)
No errors

We have to know well what kinds beam irradiate on the mirror.

31

Design parameters• Coating material : Rh, Pt, Ni … ( w/o binder , Cr ), thickness: multilayers ( ML ), laterally graded ML• Incident angle: grazing angle ( mrad )How to select• Surface shape: flat, sphere, cylinder, elliptic …
: adaptive (mechanically bent, bimorph )• Substrate shape : rectangular, trapezoidal…
• Substrate size
: length, thickness, width• w/o cooling: indirect or direct, water or LN2…
• Substrate material : Si, SiO2, SiC, Glidcop…
In addition,some errors such as figure error, roughness…

32

How to select coating material and incident angle ?

The complex atomic scattering factor for the forward scattering

Reflectivity for grazing incident mirrors

k1 

2



cos  , k 2 

k1  k 2
k1  k 22

f  f1  if 22n  1    iThe complex index of refraction

r0 
33

Coating material ( 2 )“total reflection”
2

1

2

0.744

Quartz

0.555

2.33

Pt

3.26

20.7

Au

2.96

19.5


4

μ: linear absorption coefficient34

Ec  20  i
E c ( eV ) , ρ ( g / cm3 ), θ c ( mrad )

1.0
0.8
0.6

L-edge0.4

K-edge0.2

Rhi (mrad)
3
4
5
6
7
8
9
10

0.0

1   2   c

5

1.0

10

15

20

Energy (keV)25 c  2  1.6 102    20  E

Reflecticity

cos( c )  n  1   , cos( c )  1   c 2

0.6

M-edge0.4
0.2
0.0( rad ), ρ ( g / cm3 ) , λ ( nm ) , E ( eV )Absorption
0

5

10

15

30

Pt
i (mrad)
3
4
5
6
7
8
9
10

L-edge0.8

Pt ( 21.4 g / cm3 )2θc
For example,3
Rh ( ρ = 12.4 g /cm ) λ=0.1nm, θc =5.68 mrad

0.488

N: Number of atoms per volume

Rh ( 12.4 g / cm3 )1   c

Si



0

1   cβ(×10 ‐7)

The cut off energy of total reflection Ec

Incident angle smaller than critical angle,
Total reflection occurs

1e2
 2.82  1015 m
4mc 2

δ (×10 ‐5)

Coating material ( 3 ) : “cut off, absorption”

n1 n2  cos(1 ) cos( 2 ) ←Snell’s law

1

E  e  i (t kr )

Nr02

f1 ( )
2Nr02
f 2 ( )2n 2  cos 2 



Small
for x‐ray region

The complex index of refraction

Reflecticity

R ( ,  , n ) Coating material (1)“the complex index of refraction”

20

25

30

Energy (keV)35

Cut off energy, absorption → incident angle→ Opening of the mirror, length, width of mirror, power density 36

Surface shape (1)Atomic scattering factors, Reflectivity

Purpose of the mirror

for example,• deflecting• low pass filter• focusing• collimate

You can easily find optical property in “X‐Ray Data Booklet”
by Center for X‐ray Optics and Advanced Light Source,
Lawrence Berkeley National Lab.
In the site the reflectivity of x‐ray mirrors can be calculated.

http://xdb.lbl.gov/

Easy to make or cost

• flat• spherical• cylindrical• toroidal• elliptical• parabolic…
adaptive• meridional• sagittal

◎
◎
○
○
△
△
△

Take care ofaberration

Many thanks to the authors !
37

38

Surface shape (2) radius and depth2Rm 1 p  1 q sin  i 
2 sin  i 
Rs  Rm sin 2  i 
1 p  1 q 

For parallel beam

By Fermat’s principle

Basic geometry

ESRF

The optical path length :spherical or cylindrical shape → not constantelliptical shape → constantq  ,1 / q  0

Depth at the center D  R  R   L   L
22

 2R 

2

8R

For example,
p=15～50m, q=5～20m θi=1～10mrad
Rm=0.1～10 km, Rs= 30～100 mm
R=1 km, L=1m → D = 125 μm

S

R

F
p

D

L

39

by courtesy of Ch. MoraweqSurface shape (3) elliptical

Mirror optics

ESRF

x2 y2

1
a2 b2

Elliptical shape is suitable for point‐to‐point focusing.

z

For example,

q2

Depth(m)

15

q1

p2

( x0, y0 )pq2b  sin( ) pq
x0 

10

p2  q2
2 p 2  2 pq cos( 2 )  q 2
2y0   b 1 

5

u
0

s

a

p  975 m , q  50 mm ,   3 mrad
p1

q

p

0

10

20

30

Position(mm)

40

50

x0
a2

b
 x0
a
2
2
a  x02

 s  cos( u )  x 0 z ( s )   cos( u )  b 1    s  cos( u ) sin(  u )aPrecise fabrication is difficult.

( Ref * )* M.R Howells et al., “Theory and practice of elliptically bent X‐ray mirrors”, Optical Eng. 39,
422748 (2000).

Constant optical path = p1+q1 = p2+q2 =・・・
by courtesy of Ch. Morawe

Elliptical mirror mechanically bent
using trapezoidal substrate
Trapezoidal mirror (L170mm)

Trapezoidal mirror (L540mm)

Dynamically bent KB mirror
at ESRFLong bent focusing mirror
at SPring‐8

These system works fine to focus micro beam.

ESRF

Mirror optics

Elliptical shape is suitable for point‐to‐point focusing.

Opening of a mirror restricts focusing size.
→ see #77
43

by courtesy of Ch. Morawe

Multilayer coating mirror

Multilayer optics

ESRF

To enlarge opening of a mirror, multilayer is useful.

advantages
enlarge opening of a mirror
higher critical angle
moderate energy resolution

q

q

A
B

L
L*sinqdisadvantages
chromatic
damage ?
cost ?
“Juni Hito‐e”
a 12‐layered ceremonial kimono
46

by courtesy of Ch. Morawe

X‐ray multilayer reflectivity

ESRF→ see #35

 c  20  E  0.25 deg W : ρ=19.25g/cm3

Numerical calculations
Main features• Bragg peaks and fringes due to interference• Positions depend on E and Λ• Intensities depend on Δρ, N, σ…
Bragg Eq .&Snell’s law

Corrected Bragg equation

ESRF

X‐ray multilayer characterization

Transmission electron microscopy (TEM)• Fabrication errors• Roughness evolution• Crystallinity• Interface diffusionm    2    n2  n1 cos 2 
2For θ >> θC →

n1
L

2

m    2    sin qComplementary to x‐ray measurements !

q

A
B

n2

R. Scholz, MPI Halle, Germany

L*sinq

Two materials of high and low atomic number are alternately deposited to maximize the difference in electron density.
→ The multilayer coating allows larger incident angle for x‐rays depending on the periodicity (Λ).
by courtesy of Ch. Morawe

by courtesy of Ch. Morawe[W/B4C]50

X‐ray reflectivity

ESRF

ESRF

Energy resolution of multilayers

Reflectivity and phase[Ni/B4C]20/Si

Ni/Si

by courtesy of Ch. Morawe

ESRF

by courtesy of Ch. Morawe

X‐ray multilayer design

Period number N: can control reflectivity and energy resolution.
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 !

by courtesy of Ch. Morawe

Design parameters of x‐ray mirror
Requirement

the beam properties both of incident and reflected x‐rays( size, angular divergence / convergence, direction, energy region, power… )Design parameters• Coating material : Rh, Pt, Ni … ( w/o binder , Cr ), thickness: multilayers ( ML ), laterally graded ML• Incident angle: grazing angle ( mrad )• Surface shape: flat, sphere, cylinder, elliptic …
: adaptive (mechanically bent, bimorph )• Substrate shape : rectangular, trapezoidal…
• Substrate size
: length, thickness, width• w/o cooling: indirect or direct, water or LN2…
• Substrate material: Si, SiO2, SiC, Glidcop…
In addition,some errors such as figure error, roughness…

52

“An actual mirror has some errors.”

200

25nm
100

The tolerance should be specified to order the mirror

0
0.0

0.2

0.4

Tailoring x‐rays
to application↓
X‐ray mirrors
design, errors, metrology& alignment

0.6• Reflectivity• Beam size
• Distortion• Deformation …

• Roughness• Density of coating material• Radius error• Figure error

0.8

Position (m)
No errors

The cost ( price and lead time) depends entirely on tolerance.
We must consider or discuss how to measure it.

• Deformation by self‐weight, coating and support …
• Figure error of adaptive mechanism• Misalignment of mirror• Stability of mirror’s position ( angle )• Environment• Deposition of contamination by use• Stages• Decomposition of substrate by use• Cooling system …
54

53

Errors ( 1 )“Density ρ and surface roughness σ ”

Contamination and removal
beforeE c  20   i

R  R0eRhi: 4 mrad
Density ρ
100 %
90 %
80 %

0.6
0.4

0.6
0.4
0.2

0.2

0.0

0.0
0

5

10

15

20

Energy (keV)

UV / ozone cleaning2Rhi: 4mradrms roughness σ
0 nm
1 nm
2 nm

0.8

Reflecticity

0.8

After cleaning

 4 sin  i  






1.0

1.0

Reflecticity

Intensity (a.u.)

300

25

30

0

5

10

15

20

25

30

Energy (keV)

Coating on sample wafer at the same time is helpful to evaluate the density and roughness.

It takes from 10 min to a few hours.

55

56

Errors ( 2 )“the self‐weight deformation”
FEA (finite element analysis )Errors (3a)“figure error estimated by Rayleigh’s rule ”

Material
SiO2
Density
2.2 g / cm3
Poisson's ratio 0.22
Young’s modulus E = 70 Gpa

DSupported by 2 lines

This value is larger than figure error by Rayleigh’s rule.

  hk sin( )   2h / 4  

0.06nm (20keV) 3mrad
0.08nm (15keV) 3mrad
1 nm ( 1keV) 10mrad

2nm
3nm
12nm

4

L
E  t3h( →See next page )Improvement for nano‐focusinga) Substrate → Si ( E ～ 190 GPa )b) Optimization of supporting points and methodc) Figuring the surface in consideration of the deformation

58

57

Errors (3b)Errors (3c)“ estimation by wavefront simulation ”“ estimation by wavefront simulation ”

0

0

10

20

30

40

1
0
-1
0

10

50

Position(mm)

20

30

40

50

Position (mm)Position(mm)

0

0

10

20

30

40

1
0
-1
0

10

Position(mm)2030Position (mm)Position(mm)

50

40

50

Errors of long range order

Designed surface

Intensity profiles of focusing beam by wavefront simulation

Intensity profiles of focusing beam by wavefront simulation

300

300

Intensity (a.u.)

Intensity (a.u.)

5Errors of short range order

Designed surface

200

25nm
100

0
0.0

p=975m, q=50mm,
θ=3mrad, L=50mm

10Figure error
Height error
(nm)
(nm)

5

15

Height(m)p=975m, q=50mm,
θ=3mrad, L=50mm

Figure error
Height error
(nm)
(nm)

Height(m)

15
10

8

0.2

0.4

0.6

Position (m)
No errors

0.8

0.2

0.4

0.6

0.8

Position (m)
3nmPV (0.85nmRMS)

0.2

0.4

0.6

0.8

Position (m)
9nmPV (2.5nmRMS)

0.2

0.4

0.6

0.8

1.0

Position (m)
30nmPV (8.5nmRMS)

Errors of short range order decreases intensity. → Roughness
59

200

25nm
100

0
0.0

0.2

0.4

0.6

Position (m)
No errors

0.8

0.2

0.4

0.6

0.8

Position (m)
3nmPV (1.1nmRMS)

0.2

0.4

0.6

0.8

Position (m)
9nmPV (3.2nmRMS)

0.2

0.4

0.6

0.8

1.0

Position (m)
30nmPV (11nmRMS)

Errors of long range order loses shape. → Figure

60

300

Middle range
1.5

0.5
0.0
-0.5
-1.0
-1.5
0

20

30

40

50

0.5
0.0
-0.5
-1.0
-1.5
0

300

Position (mm)

250

10

20

30

40

200
150
100
50
0
0.0

0.2

0.4

0.6

0.8

1.0

150
100
50
0
0.0

0.2

0.4

0.6

0.8

Position (nm)Position (nm)

誤差なし
3nmPV (0.85nmRMS)
9nmPV (2.5nmRMS)
30nmPV (8.5nmRMS)

誤差なし
3nmPV (0.9nmRMS)
9nmPV (2.8nmRMS)
30nmPV (9.4nmRMS)

Intensity reduced

0.5
0.0
-0.5
-1.0
-1.5
300

200

0

10

20

30

40

50

Position (mm)250

Designed shape10

d DL  25 nm

200

25nm
100

0
0.0

0.2

0

0

10

20

30

40

50

Position(mm)

150
100
50
0.2

0.4

0.6

0.8

1.0

Position (nm)Performed 25nm

誤差なし
3nmPV (1.1nmRMS)
9nmPV (3.2nmRMS)
30nmPV (11nmRMS)

Shape loses

25nm

If the figure error < 3nmPV for all spatial range,
the estimated focusing size performs 25 nm.
The value corresponds to the result of Rayleigh’s rule.

0.4

Tailoring x‐rays
to application↓
X‐ray mirrors
design, errors, metrology& alignment

0.6

0.8

Position (m)
No errors

5

200

0
0.0

1.0

15

1.0

50

Position (mm)250

Intensity (a.u.)

Intensity
Intensity (a.u.)

10

1.0

Depth(m)

1.0

1.5

Height error (nm)Height error (nm)Height error (nm)

1.5

300

Long range

Intensity (a.u.)

Figure error

Short range

Intensity (a.u.)“ estimation by wavefront simulation ”

The focusing beam of 25 nm was realizedusing high precision mirror with figure error of 3 nm PV*H. Mimura, H. Yumoto, K. Yamauchi et.al, Appl. Phys. Lett. 90, 051903 (2007).61

How to evaluate the errors ?

Metrology instruments for x‐ray optics

Designed surface

Field of view, lateral resolution
Long /
Short /Long /
middlemiddlemiddle～1m,
Short～10 mm, ～ 0.1 m,
1 mm Slope～10 μm,1 μm
0.1 mmFigureRoughness, figure
0.1 nmDepth(m)

15
10
5
0

0

10

20

30

40

50

Position(mm)Figure error(nm)

Figure error
(nm)

1
0
-1
10

20

30

Position (mm)40

Roughness

Errors ( long range )Errors ( short range )

0

62

50

1

Long Trace Profiler( LTP )

0
-1
0

10

20

30

40

50

Scanning probe
microscope

Position (mm)63

z (0.1nm)

Scanning white lightinterferometer

Fizeau interferometerz (0.1nm) z (0.1nm)
Vertical resolution (rms)slope(0.1urad)64

Fizeau interferometer

Scanning white light interferometer

Interference pattern → Height

Commercially available

Interference fringe → Height

Monochromatic
point light source

Commercially available

Zygo Corp. VeriFire®,
4DS technologies,
FujiFILM ……

Fringes on CCD
Beamsplitter
Beam
splitter

-1
0

10

20

Direction of laser reflected on the surface → Slope

Scanning penta prism

UnderMirror
the test

0-1

00.5µrad

0.0

REF for monitoring stability of system

Easy to measure slope of sub‐μrad on large mirror by NO reference
Many kinds of LTPs are developing among SR facilities.
67

50

0.1

1

0.2µrad

0.0

-0.2

1

3nm

0
-1
10

20

30

40

50

Position (mm)or line sensor

40

Errors ( long range )-0.1

0fθ lens Positionxd on CCD

30

0.2

-0.5

Detector

20

Figure error and slope error
0.5Light source( Laser )10

Position (mm)Errors ( middle range )LaserLong / middle range orderNot easy to measure large mirror 66

65

Homemade

For example, S. Qian, G. Sostero and P. Z. Takacs, Opt. Eng. 39, 304‐310 (2000).

1

Under the test

50

FOV (=stage)～2 m
Lateral resolution mm～
Vertical resolution 0.1 μradFZ’ : slope
Z : height

40

Slope error(urad)

d
Z '
2F

d μm
F 1m
Z’ < sub-μrad30

Position (mm)Long trace profiler ( LTP )Slope

CavityShort / middle range order

Slope error(urad)

0

Figure error(nm)

Reference

1

Figure error(nm)

Zygo Corp. NewVeiw®,
Bruker AXS (Veeco) Contour GT® .......

Collimator

3nm

0
-1
0

10

20

30

Position (mm)Errors ( short range )40

50～Δθrms×L

10

Slope error(urad)

Under the test

Height

Δθ

5

L

0
-5

Lateral resolution×-10

Figure error(nm)

Beam splitter

FOV (=lens) 50um～10 mm
Lateral resolution 1 μm～
Vertical resolution 0.1 nm
Figure error(nm)

Mirau orMichelson
objectivelensscannedReference

Fizeau fringes on CCD
FOV (=reference) ～0.1 m
Lateral resolution ～0.1 mm
Vertical resolution 0.1 nm

Figure error
(nm)

White
light source( Lamp or LED )

1

3nm

0
-1
0

10

20

30

Position (mm)

40

50

LTP :
Lateral resolution mm～
Vertical resolution 0.1 μrad

68

LTP
of ESRF, APS, SPring‐8

Detector

LTP
of ESRF, APS, SPring‐8

Detector
Optics
Laser

Optics (moving)
Laser

Part of optics (moving)
MirrorPart of optics

Laser

Detector

MirrorLaser

Mirror

Detector

Optics (fixed)

Mirror

Detector
Optics

Laser
Penta prism

MirrorPenta prism

Detector

MirrorMirror69

70

Nanometer Optical Component Measuring
Machine (NOM) @HZB

Round robin measurement of
1m‐long toroidal mirror

Autocollimator → Slope

Homemade

Scanning

Light source( LED or laser )Under the test

Slope error profile

Figure error profile
F. Siewert et al.: „The Nanometer Optic Component Measuring Machine: a new Sub-nm Topography“ SRI 2003, AIP Conf. Proc.

L. Assoufid, A. Rommeveaux, H. Ohashi, K. Yamauchi, H. Mimura, J. Qian, O. Hignette, T. Ishikawa,
C. Morawe, A. T. Macrander and S. Goto, SPIE Proc. 5921-21, 2005, pp.129-140.

71

72

Intensity (a.u.)

300

Stitching interferometer for large mirror
Homemade

200

25nm
100

0
0.0

MSI

RADSI

( micro‐stitching interferometer )( relative angle determinable stitching interferometer )

0.2

0.4

Microscopic
interferometer head
Test mirror

FizeauElevation
Pitch
Pitch

Roll

0.5m
Test mirror

Horizontal scan

Collaboration with Osaka Univ., JTEC and SPring‐8
H. Ohashi et al., Proc. Of SPIE 6704, 670405‐1 (2007).

Height error of wide range order for a long and aspherical mirror
with 1μm of lateral and 0.1 nm of vertical resolution.

Necessity is the mother of invention.

Elliptical mirrors
In 1948, P. Kirkpatrick and A. V.
Baez proposed the focusing opticalsystem.

74

Overview of
x‐ray focusing devices
Diffraction

Kirkpatrick‐Baez (K‐B) mirrors

Disadvantages
Difficulty in mirror alignments
Difficulty in mirror fabrications
Large system

Suitable forx‐raynano‐probefocus size,
focal length[energy]aberration-coma-chromatic-figure error

Fresnel Zone Plate

-coma
small
soft x-ray -chromatic
hard x-ray exist-figure error
small

Sputter sliced FZP

0.3 µm,f = 22 cm[12.4 keV],
0.5 µm,f = 90 cm[100 keV]

-coma
small
-chromatic
exist-figure error
large→small

2.4 µm,f = 70 cm[13.3 keV]
Bragg FZP

Multilayer Laue Lens

75

energyrange

12 nm,
f = 0.16 mm[0.7 keV],
30 nm,
f = 8 cm
[8 keV]P. Kirkpatrick and A. V. Baez, “Formation of Optical Imagesby X‐Rays”, J. Opt. Soc. Am. 38, 766 (1948).

Large acceptable aperture and High efficiency
No chromatic aberration
Long working distance

0.8

73

Introduction of KB mirrors

Advantages

Tailoring x‐rays
to application↓
X‐ray mirrors
design, errors, metrology& alignment

0.6

Position (m)
No errors

8-100
keV

-coma
small
mainly -chromatic
hard x-ray exist-figure error
small

16 nm(1D),-coma
f = 2.6 mm
large[19.5 keV],
mainly -chromatic
25nm×40nm, hard x-ray exist
f=2.6mm,4.7mm-figure error[19.5 keV]
small

Refraction

Pressed Lens

focus size,
focal length[energy]
1.5 µm,f = 80 cm[18.4 keV],
1.6 µm,f = 1.3 m[15 keV]
47nm×55nm,
f = 1cm, 2cm[21 keV]

Etching Lens

energyrange

aberration-coma-chromatic-figure error

-coma
small
mainly-chromatic
hard x-ray
exist-figure error
large
-coma
small
mainly-chromatic
hard x-ray
exist-figure error
small

Reflection

Kirkpatrick-Baez Mirror

36nm×48nm,
f=15cm,25cm[15 keV],
7 nm(1D),
f=7.5cm[20 keV]

-coma
small
-chromatic
not exist-figure error
large

0.7 µm,f = 35 cm[9 keV]<10 keV

95 nm,[10 keV]

-coma
large
soft x-ray -chromatic
hard x-ray
not exist-figure error
large

Wolter Mirror

X-ray Waveguide

-coma
large
soft x-ray -chromatic
hard x-ray
not exist-figure error
smallHow small is x‐ray focused ?

Nano‐focusing by KB mirror
History since the century

For example, by elliptical mirror

p

q



10
200

150

0

l

0

10

20

30

40

50

Position(mm)Geometrical size

0.88q
d DL   
l sin( )40nm
30nm 25nm
15nm

0
2001

2002

2003

2004
Year

2005

d G  5 nm  d DL  25 nm

Multilayer mirror

7nm
2009

World Record of spot size is 7 nm (by Osaka Univ., in 2009 *).

Ref * : H. Mimura et al., “Breaking the 10 nm barrier in hard‐X‐ray focusing”, Nature Physics 6, 122 (2010).78

KB optics installed in BL29XU‐L

Difficulty in mirror alignments

1st Mirror

Incident slit
Focal length f

ψ

2007

Routinely obtained spot size is up to 30 nm.

The opening of the mirror restricts the focused size even if magnification is large. 77

φ

2006

World Record of Spot Size
Focused by KB optics

p  975 m , q  50 mm ,   3mrad , l  50 mm ,    nm , S 0  100 m
Mag. = 1 / 19500 !

90nm

100

50

Diffraction limited size(FWHM)qd G   S0
p

180nm

5
Spot size (nm)S0

Depth(m)15

2nd Mirror(Vertical focusing) (Horizontal focusing)
100mm

Undulator
Focal length f

Focal point

100mm

θ

ψ

DCM

X-ray

45m
98m

st

1 Mirror
Front View

Positioning two mirrors is difficult
because there are at least 7 degree of freedom.

It is difficult to use KB mirrors.
79

150mm

Side View

Glancing angle (mrad)
Mirror length (mm)Mirror aperture (m)
Focal length (mm)Demagnification
Numerical aperture

1st Mirror
3.80
100
382
252
189
0.75x10-3

2nd Mirror
3.60
100
365
150
318
1.20x10-3

Coefficient a of elliptic function (mm)23.876 x 103

23.825 x 103

Coefficient b of elliptic function (mm)13.147

9.609

Diffraction limited focal size
(nm, FWHM)

48

29

2nd Mirror
Side View

102mm

Ref :H. Mimura, H. Yumoto, K. Yamauchi et.al, Appl. Phys. Lett. 90, 051903 (2007).

80

Tolerance limits of mirror alignmentsψ

1st Mirror

2nd Mirror
250

Ho rizo nta l focusing
Vertical fo cu sin g

200～0.1 μrad
Beam size (nm)Be am size ( nm)

X-raySide View

Front View

200

Severe positioning of
two mirrors is required.
The manipulator should bedesigned for these freedom of axis
with the resolution & the range.


ψ

θ



250

150
Diffractio n l imit invertical fo cu sin g
100

50

250

Horizontal focusing
Vertical focusing～1000 μrad150
Diffraction limit invertical focusing
1000Diffraction limit invertical focusing
100

1

2

0
-200

3

0
-100

0

100

-50

200

Perpendicularity errors (rad)
Perpendicularity
 rad)errors 

Glan cin g a ngle er rors (rad)

Errors of L  2  xx

2LDiffraction limit inhorizontal focusing

Diffraction limit inhorizontal focusing

0
-1

150

50

50

-2

Horizontal focusing
Vertical focusing

200～10 μradDiffracti on limit inh orizontal fo cu sin g-3

Image on X‐ray CCD cameraφBeam size (nm)



-30

-10

10

30

50

In-plane rotation errors (mrad)
In-planerotation mrad)errors 

Freedom of axis, Resolution, range

Ref: S. Matsuyama, H. Mimura, H. Yumoto et al., “Development of mirror manipulator for hard‐x‐ray nanofocusing
at sub‐50‐nm level”, Rev. Sci. Instrum. 77, 093107 (2006).

1m from focal point( CCD )

81

82

Alignment of in‐plane rotation(Horizontal focusing mirror)

Image of reflected x‐ray
Upper
8.28mm(1.150 m×3.6 mrad × 2)

x‐z planez

1508μm(380×(1/0.252))
2400μm(360×(1/0.150))

Side View
Reflected light(twice)Reflection in a verticaldirectiony‐z planez

Horizontal focusing
mirror

y

x

φH
2θ
X‐ray

9.52mm(1.252m×3.8 mrad×2)

Focal plane

θ

Rail

Focal point
Vertical focusing
mirror

1.92mm(0.252 m×3.8 mrad×2)(X‐ray)Max 360μm
Max
380μm

Ring

Reflection in ahorizontal direction

θ: 3.8mrad→ 2θ: 7.6mrad
Direct x‐ray

Reflected angle of vertical‐focusing mirror needs to be considered,in the alignment of in‐plane rotation of horizontal‐focusing mirror.

(Mirror aperture)
1.08mm(0.150 m×3.6 mrad×2)
83

84

Alignment of incident angle

Alignment of incident angle

・ Foucault test
Rough assessment of focusing beam profile.
This method is used for seeking focal point.

X‐ray

X‐ray
CCD
cameraX‐ray Mirror

・Wire (Knife‐edge) scan method
Final assessment of focusing beam profile.
X‐ray

Precise adjustment of the glancing angle andfocal distance is performed until the best focusing
is achieved, while monitoring the intensity profile.

X‐ray
CCD
cameraX‐ray Mirror

85

Foucault test

86

Foucault test 1

Image on CCD Projection image

Wire is at downstream of focal point.
Image on CCD become dark from lower side.

Downstream

Focal plane

X‐ray

Knife edge

Upstream
Whole bright‐area
gradually becomes dark.

X‐ray CCD
cameraEdge shadow
Focal point↓

Knife edge

Knife edge shadow
87

88

Foucault test 2

Foucault test 3

Wire is at upstream of focal point.
Image on CCD become dark from upper side.

Wire is at the focal point.
Whole bright‐area gradually becomes dark.

X‐ray CCD
camera

Focal point
↓

X‐ray

Focal point
↓

X‐ray

Knife edge

X‐ray CCD
cameraKnife edge

89

Relationshipbetween incident angle and focal position

90

Wire (Knife‐edge) scan method for measuring beam profiles
The sharp knife edge is scanned across the beam axis, and the total intensity of the transmitting beamis recorded along the edge position.

Focal point

Tolerance of the incident angle→ only a few micro‐rad

Intensity
Detector
(PIN)

X‐ray

Wire

X‐ray
The line‐spread function of the focused
beam was derived from the numericaldifferential of the measured knife‐edge
scan profiles.

Incident angle→Large ⇒ Focal point → downstream
Incident angle→Small ⇒ Focal point → upstream

Intensity (arb. unit)

1.2
Wire scan profile

1.0
0.8

Differential
profile

0.6
0.4
0.2
0.0

-0.2
-200 -150 -100

91

-50
0
50
Position (nm)

100

150

200

92

Relationship between Beam size and Source size

Relationship between Beam size and Source size

Beam size changes depending on source size (or virtual source size).
Undulator

Focal point

100mm

DCM
45m
98m

Beam size = Source size / M
ANDBeam size ≥ Diffraction limit

102mm

10m (Experimental)
50m (Experimental)
100m (Experimental)
10m (Calculated)
50m (Calculated)
100m (Calculated)

1.2

2nd Mirror(Vertical focusing) (Horizontal focusing)
100mm

Intensity (arb. units)

1st Mirror

Incident slit

1.4

150mm

Side View(M: demagnification)

1.0
0.8
0.6
0.4
0.2

10000

0.0
-1000

Vertical focusing
Horizontal focusing

Horizontal focusing-500

0Position (nm)

1.4
500

Intensity (arb. units)

FWHM (nm)Beam size is selectablefor each application.

100

10m (Experimental)
50m (Experimental)
100m (Experimental)
10m (Calculated)
50m (Calculated)
100m (Calculated)

1.2

Vertical focusing
1000

1000

1.0
0.8
0.6
0.4
0.2

10
1

10
100
TC1source
slit size
(m)
Light
size
(m)

1000

0.0
-1000

93

Scanning X‐ray Fluorescence Microscope: SXFM
3000

Scanning samples
Focused X‐ray

Intensity (Counts)

Cl

Ag

FeKα

2500

Si

2000

On a細胞中央
Cell
細胞なし
Out of Cells

1.

To select the functions of x‐ray mirror

2.

To specify the incident and reflected beam properties

FeKβ
Cu

ElasticZn00

X‐ray fluorescence2

4
6Energy (keV)

8

94

1000

Energy range , flux
→ absorption, cut off energy → coating material → incident angle
The beam size and the power of incident beam
→ opening of the mirror, incident angle→ absorbed power density on the mirror → w/o cooling, substrate
Angular divergence / convergence, the reflected beam size
→ incident angle, position of the mirror ( source, image to mirror )Direction of the beam
→ effect of polarization, self‐weight deformation

1000

Ca

500

Key issues of x‐ray mirror design

S

500

0
Position (nm)Deflecting, low pass filtering, focusing and collimating → Shape of the mirror

S
i

1500

-500

10

X-ray Fluorescence spectrum

4.

To specify the tolerance of designed parameters
Roughness, density of coating material, radius error, figure error
The cost ( price and lead time) depends entirely on the tolerance.

X‐ray spectrometer
Measurement principle

5.
S

Zn

Scanning pitch: 1000nm Scan
area: 60×50m

Ref: M. Shimura et al., “Element array by scanning X‐ray fluorescence microscopy after cis‐diamminedichloro‐platinum(II)95
treatment”, Cancer research 65, 4998 (2005).

To consider the alignment
The freedom, resolution and range of the manipulator
96

Key issues for the beamline design
Key issues

Design components

Which application is the most important at the BL?

• End station( pressure, temperature,• Sample environment
magnetic field…)• Detector, data processing … ( automation )Can you specify who uses the property at the BL ?
•
•
•
•
•
•

–
–
–
–
–

Photon energy, energy resolution
Flux, flux density
The higher, the better ?
The smaller, the better ?
Beam size
More is NOT always better !
Polarization
Spatial coherence Simplify the property.
Time resolution Get your priorities right.

Time schedule
Human resources
Available budget, space, technical level
Maintenance for keeping performance
Lifetime of the BL ( hardware and application )What to include or not ?
What to develop or not ?

•
•
•
•
•
•

Ongoing x‐ray beamline
X‐ray beamline looks complicated, but the function of each component is simple.
To specify the beam properties is to design the beamline.
New x‐ray beamline for next generation light source such as XFEL is newly constructed.
The components for heat management, x‐ray beam monitors and x‐ray optics
including metrology are newly developed to perform the beam properties.

Light source (ID, BM)
Monochromator, higher order suppression…
Focusing devices…
Polarizer…
Stability enoughWindow…
to measure
RF timing, chopper…

Challenges at XFEL beamline :• Radiation shielding hutch …
• Interlock system• Beam shutter…
•
•
•
•
•
•

Safety first !

Absorber, FE slit
Cooling method, cooling system
Selection of light sources ( power, angular dist.)
Electronics in hutch ( detector, controller … )Embrittlement (cable, tube )Contamination on optics• Electricity, water, air, network, control• Environments ( temperature, vibration… )Simple and clear design to accelerate your research97

Acknowledgment

coherence preservation
wavefront disturbance or control
at wavelength techniqueultra‐short & high intense pulse
high stability
shot‐by‐shot diagnosis of x‐raystiming control of x‐ray pulse
synchronization with other source …

98

Thank you for your kind attention.

S. Takahashi ( front end ), H. Aoyagi (XBPM),
T. Matsushita ( interlock ),H. Takano, Y. Kohmura, T. Koyama, ( focusing devices )T. Uruga, Y. Senba ( mirrors ),S. Matsuyama, H. Yumoto, H. Mimura, K. Yamauchi( ultimate focusing mirror, alignment ),C. Morawe ( multilayer ) ESRF
S. Goto and T. Ishikawa

Enjoy Cheiron school
Enjoy SPring‐8
andEnjoy Japan!
99100