PF-2.5GeV PF-AR Ｎ KEK layout k. ito 1 JASS2002 Oct 21, 2002.

PF-2.5GeV

PF-AR

ＮKEK layoutKEK layout

k. ito 1JASS2002Oct 21, 2002

Layout of the Photon FactoryLayout of the Photon Factoryk. ito 2JASS2002Oct 21, 2002

Synchrotron radiation beamlines Synchrotron radiation beamlines in the vacuum ultraviolet and in the vacuum ultraviolet and

soft X-ray region soft X-ray region

k. ito 3JASS2002Oct 21, 2002

Kenji ITO e-mail: [email protected] ITO e-mail: [email protected] Factory, IMSS, KEK, Tsukuba, Ibaraki 305-0801, JapanPhoton Factory, IMSS, KEK, Tsukuba, Ibaraki 305-0801, Japan

IntroductionOptical elements

mirrors geometrical shape reflectivity

grating basic understanding geometrical optics ray tracing varied-line spacing grating

Monochromators normal incidence type grazing incidence typeSummary

What is the role of beamlines for SR usage?What is the role of beamlines for SR usage?

1)1) conducting SR from the storage ring to the conducting SR from the storage ring to the 　　 experimental stationsexperimental stations

2) shaping SR beam, 2) shaping SR beam, spatiallyspatially and and energeticallyenergetically, , to meet the experimental requirementsto meet the experimental requirements

k. ito 4JASS2002Oct 21, 2002

k. ito 5JASS2002Oct 21, 2002

VUV: vacuum ultraviolet

EUV: extreme ultraviolet

SX: soft X-ray

Definition of VUV and SXDefinition of VUV and SX

D. Attwood, “Soft X-rays and extreme ultraviolet radiation” (1999)

VUV-SX photons cannot propagate in the atmosphere!!!

IR

UV

VUV Soft X-rays

Extreme Ultraviolet Hard X-rays

1 eV 100 eV10 eV 1 keV 10 keV

1 m 100 nm 10 nm 1 nm 0.1 nm

2a0

SiLCK OK SiK CuK

BeSiO2

NK

VUV-SX beamlines must be kept atVUV-SX beamlines must be kept at

k. ito 6JASS2002Oct 21, 2002

2) Not to disturb the storage ring no mechanically-rigid window is available!!!

1) To facilitate the propagation of the VUV-SX photons

3) To protect the optical elements from contamination, oil-free primary pumps are recommended!!!

ultra-high vacuum (UHV)ultra-high vacuum (UHV)

Interlock System

X-ray Beamline

VUV Beamline

SR

Hutch

Layout of a typical beamline Layout of a typical beamline

pre-focusing mirror monochromator post-focusing mirror

main beam-shutters

k. ito 7JASS2002Oct 21, 2002

shielding wall branch-beam shutters

Construction of a VUV-SX Construction of a VUV-SX beamlinebeamline

What kinds of measurements are required?

Photon energy rangePhoton fluxBeam sizePhoton band width PolarizationPurityCoherence

Beamline optics pre-focusing mirrors monochromator post-focusing mirrors

Light source bending magnet undulator multipole wiggler

This procedure does not work for a multipurpose beamline.

k. ito 7JASS2002Oct 21, 2002

2) diffraction gratings, zone plates, multi- layered mirrors, filters and crystals as dispersion tools

Optical elements Optical elements used in the VUV-SX beamlinesused in the VUV-SX beamlines

k. ito 9JASS2002Oct 21, 2002

monochromators as a beamline system

1) reflection mirrors as a focussing tool

1) focusing of VUV-SX light by various shapes of mirror: sphere, cylinder, parabola, paraboloid, ellipse, ellipsoid, toroid, et

c

Mirrors for SR useMirrors for SR use

k. ito 10JASS2002Oct 21, 2002

with modern technology: 1-m long mirrors available surface roughness < 0.5 nm in rms slope error < 1 rad beamspot size

2) for better reflectivity in the VUV-SX region: substrate: SiC, Si, SiO2, metal, other glass coating materials: Au, Pt, Os,…

Focusing mirrors of spherical shape Focusing mirrors of spherical shape

Aberration of spherical mirror

focussing plane

Rrr

Rrr

rOCrOBrAO

s

t

st

cos211

cos

211

A

O

BC

Rowland circle

Astigmatism of spherical mirror

k. ito 11JASS2002Oct 21, 2002

To avoid astigmatism: To avoid astigmatism: Focusing mirrors of toroidal shapeFocusing mirrors of toroidal shape

sagittal

tangential

cos2

'

11

cos

2

'

11

rr

RrrR

r

r´

source

focus

k. Ito 12JASS2002Oct 21, 2002

Parabolic mirrors to avoid aberration Parabolic mirrors to avoid aberration

Y2=4aX

a=f cos2

In 2D focusing: paraboloidal

k. Ito 13JASS2002Oct 21, 2002

Elliptical mirrors to reduce aberrationElliptical mirrors to reduce aberration

(X/a)2+(Y/b) 2 =1

F1

F2

For 2D focusing: ellipsoidal shape mirrors

k. Ito 14JASS2002Oct 21, 2002

Reflectivity of mirrorsReflectivity of mirrors

2222

1

2222222

2222

1

2222222

2222

2222

222

222

sin4sin2

sin4sin2

tansintansin2

tansintansin2coscos2

coscos2

knknknb

knknkna

aba

abaRR

sba

sbaR

sp

s

Complex refractive index Ñ = n - ik

complex dielectric constant

complex atomic scattering factor

k. Ito 15JASS2002Oct 21, 2002

Rs=Rp2 for 45°

Reflectivity of gold at 21.2 eVReflectivity of gold at 21.2 eV

0 10 20 30 40 50 60 70 80 900.0

0.2

0.4

0.6

0.8

1.0

Rp

Rs

Refl

ecti

vity

Incidence angle

k. Ito 16JASS2002Oct 21, 2002

Brewster angle

Rp=0 for dielectric material

Atomic scattering factor for AuAtomic scattering factor for Au

Henke, Gullikson and Davis, Atomic Data and Neclear Data Tables, 54, 181 (1993)

)()2/(

)(

~

2

022

2

1

21

a

a

CEfE

dCZf

iffF

2

1

1

DfDf

iK

KN

iknN~~

~

2

k. Ito 17JASS2002Oct 21, 2002

Reflectivity of goldReflectivity of goldfor s-polarizationfor s-polarization

Mirrors can play the role of low pass filters.

M5L3N

k. Ito 18JASS2002Oct 21, 2002

Henke et al., Atomic and Nuclea Data Tables, 54, 181 (1993)

1°=17.45 mrad

Surface roughness reduces the reflectivitySurface roughness reduces the reflectivity

k. Ito 19JASS2002Oct 21, 2002

0 10 20 30 40 500.0

0.2

0.4

0.6

0.8

1.0

30 deg5 deg

glancing angle =1 deg

normal incidence

Ref

lect

ivit

y

wavelength (nm)

0 2 4 6 8 100.0

0.2

0.4

0.6

0.8

1.0

30 deg

5 deg

glancing angle =1 deg

normal incidence

Ref

lect

ivit

y

wavelength (nm)

R=R0 exp[-(4sin/)2]

: micro surface roughness in rms <0.5 n

m: glancing angle

Gratings as Gratings as dispersion elementsdispersion elements

Diffraction gratingZone plateMulti-layered mirrorFiltersCrystals

1) Introduction2) Efficiency3) Geometrical optics ray tracing4) Varied-line spacing grating

k. ito 20JASS2002Oct 21, 2002

Equation for diffraction gratingEquation for diffraction grating

a: amplitude of incident light

I has maximal values for =2m.

2/sin

2/sin

sinsin/

sinsin/sin2

2

22

22

N

b

baI

)sin(sin2

d

d

m sinsin

- 4 -3 -2 -1 0 1 2 3 40

10

20

30

40

N=10

d=5b

I

m - 1 0 10

10

k. ito 21JASS2002Oct 21, 2002

Dispersion of diffraction gratingDispersion of diffraction grating

Angular dispersion:

Reciprocal linear dispersion:

m

d

cos

mmnmmmmr

mmd

q/

]['

coscos][106

d

m sinsin

r´

q

grating

Focal plane

k. ito 22JASS2002Oct 21, 2002

Diffraction efficiencyDiffraction efficiency

Diffraction efficiency can be calculated by the scalar theory for /d<<1. Rigorous numerical calculations based on Maxwellequations gives solutions with much better precision.Note that the efficiency strongly depends on the polarization ofincident radiation.

d

m sinsin

m=0

m=-1

m=-2

m=1m=2

incident light

k. ito 23JASS2002Oct 21, 2002

m>0 positive order inside orderm<0 negative order outside order

Blazed gratingBlazed grating

b

d

b

Maximal efficiency can be achieved at

-b=b-

mbK=2dsinbcosKwhere blazed wavelength is bK and deviation angle is 2K= -

k. ito 24JASS2002Oct 21, 2002

Calculated by M. Neviere

Laminar grating(1)Laminar grating(1)

0 2 4 6 8 10 120

20

40

60

80

100

m=1

m=0

Effi

cien

cy(%

)

103/ d

Grating equation

sin+sin=m/d

Efficiency

E0=100 cos2(/2)

Em=(400/m22) sin2(/2)

=(2/)h(sini+sin)

Primary maximum

/d=[2mcosi+(sin)/p]

×(p2/4+m2)

where P=h/d

i h

d

k. Ito 26JASS2002Oct 21, 2002

Laminar grating(2)Laminar grating(2)

When the path difference between 1 and 2 is equal to /2, destructive interference occurs.

h(sini+sin)= /2

normal incidence: =4h

grazing incidence: =2h(i+)h

1

2

i

Suppression of 2nd order!!!

k. ito 26JASS2002Oct 21, 2002

Geometrical optics of Geometrical optics of diffraction gratings(1)diffraction gratings(1)

k. ito 27JASS2002Oct 21, 2002

Light path functionF=AP+PB+nm 222

222

)'()'()'(

)()()(

lzwyxPB

zlywxAP

F=0, where F is the pathlengthfrom A to B. F: light path function

The red ray meets the grating at a pointP(,w,l) on the nth groove, the zerothgroove being assumed to pass through O.Two rays diffracted from the zeroth and nth grooves are reinforced when their path difference is equal to nm.

Fermat’s principle: the pathlength of anactual ray traveling from a point A to apoint B takes an extremal or stationary value.

.....8

1

4

1

8

12

1

2

1

2

1

2

1

404

2222

440

212

330

202

2201000

lFlwFwF

wlFwFlFwFwFFF

Expansion of F for z=0 and n=1/d

k. ito 28JASS2002Oct 21, 2002Geometrical optics of Geometrical optics of

diffraction gratings(2)diffraction gratings(2)

RrrRrrF

RrRrF

RrRrF

d

mF

rrF

0

0

02

0

02

30

0

002

0

0

022

20

010

000

cos

'

cos

'

sincoscossin

cos

'

1cos1

cos

'

coscoscos

sinsin

'

grating equation

defocus in y-direction

defocus in z-direction

comma

spherical aberration astigmatism


Roland mount r = R cosr0’ = R cos0

k. ito 29JASS2002Oct 21, 2002

0,00,00

l

F

w

F

l

F

w

Fl

l

Fw

w

FF ijij

Apply Fermat’s principle to F

A

BC

Rowland circle

r

r0´O

RrrRrrF

RrRrF

0

0

02

0

02

30

0

0

022

20

cos

'

cos

'

sincoscossin

cos

'

coscoscos

F20=F30=0

Geometrical optics Geometrical optics of of

diffraction diffraction gratings(4)gratings(4)

222

22

2

)(2

1

1

l

n

w

nm

l

nN

w

nMmq

ll

nmN

ww

nmMLp

lwe

eqppe

T

k. ito 30JASS2002Oct 21, 2002

0)'()'(

0)'()'(

l

nmNN

lLL

l

Fw

nmMM

wLL

w

F

nmPBAPF

lT

l

nmNN

wT

w

nmMM

TLL

'

'

'

Ray-tracing

(L, M, N):direction cosine

(L´, M´, N´)


34

0033

0122

0212

0303

2012

2102

1011100100010

34102

2111120

2300

3002

2

0110202

2002

10000

000

/

lglglg'

/

secsec'

'

)sec()sin''(

RwOfzflzzglgl

zgwwwzgwzgrY

RwOfwzwlzffwlfwfz

lzfflfwwfrY

zZ

ryY

YZ-coordinate on -plane

k. ito 31JASS2002Oct 21, 2002

Equation of image plane:

)sin(')cos('

)sin()cos(cos'

''''''

cos')sin(')cos('

00

000

000

ML

wrd

dNlzdMwydLx

ryx

where


By ray-tracing, it is possible to see 1) how the beam is focused on the slits and at F,2) how it spreads on the grating,3) the geometrical through-put.

- 0.8 -0.4 0.0 0.4 0.8-0.10

-0.05

0.00

0.05

0.10

Z(mm)

Y(mm)

Spot diagram at exit slit

k. ito 32JASS2002Oct 21, 2002

SOURCE

M M

GS

SF


3

4

0033

0122

0212

0303

2012

2102

1011100100010

3

4

1022

1111202

3003

0022

0110202

2002

10000

lglglg'

secsec'

R

wOfzflzzglgl

zgwwwzgwzgrZ

R

wOfwzwlzffwlfwfz

lzfflfwwfrY Analytical expression for spot diagrams

k. ito 33JASS2002Oct 21, 2002

i

ii

dwdldzZWLH

dwdldzYYWLH

QQ

22)(1

Analytical merit function: Q

Optimization of design parameters so as to minimize Q,where is a weight function. Triple integrals have to be doneover the grating surface. Note that Y and Z are dependent

on i (i=1, 2, …N).

Masui and Namioka, JOSA, 16, 2253 (1999)


Hybrid design method : Koike and Namioka, JESRP, 80, 303 (1996)

k. ito 34JASS2002Oct 21, 2002

kn

n

jn

inijknnnn

kn

n

jn

inijknnnn

zlwgzlwZ

zlwfzlwY

),,(

),,(

Ray-tracing of 18 rays determines fijk’s and gijk’s by solving simultaneous equations.Optimization process using the merit function in the same manner as before.

Ray-tracing program is available at http://www.xraylith.wisc.edu/shadow/shadow.html

...28

12

1,

404

2222

440

212

330

202

220

lnlwnwn

wlnwnlnwnwlwn

0

1

lww

l,wn/

=1 for mechanically ruled

grating

=/0 for holographic grating

Groove function

Effective grating constant

Varied line spacing gratings (1)Varied line spacing gratings (1)

k. ito 35JASS2002Oct 21, 2002

sin+sin=/

Varied line spacing gratings (2)Varied line spacing gratings (2)k. ito 36JASS2002Oct 21, 2002

HG´70

HG´90

RrS

RrS

RrT

RrT

R

SS

r

T

r

T

r

T

r

Tn

r

S

r

Sn

r

T

r

Tn

SSnTTn

DD

CC

DD

CC

DC

D

D

C

C

D

D

C

C

D

D

C

C

D

D

C

C

DCDC

cos1,

cos1

coscos,

coscos

.....

sin4sin4

sinsin,

sinsin

,

22

2

22

2

2

2

2

40

1230

0220

Namioka and Koike, Appl. Opt., 34, 2180 (1995)

Monochromators Monochromators in the VUV-SX region for SR use (1)in the VUV-SX region for SR use (1)

Normal incidence monochromators

k. ito 37JASS2002Oct 21, 2002

M. Koike, “Normal incidence monochromators and spectrometers” in J.A.R. Samson and D.L. Ederer Eds., “Vacuum Ultraviolet Spectroscopy II in Experimental Methods in Physical Sciences” Vol. 32, (Academic Press, New York,

1998, Chapter 1, pp. 1-20 review

(A) Seya-Namioka type monochromator(B) Pseudo Rowland mount monochromatorK. Ito, Y. Morioka, M. Ukai, N. Kouchi, Y. Hatano and T. Hayaishi, RSI, 66, 2119 (1995)

(C) Eagle type monochromator1) 6.65-m Eagle at BL-12B of the Photon FactoryK. Ito, T. Namioka, Y. Morioka, T. Sasaki, H. Noda, K. Goto, T. Katayama and M. Koike, Appl. Opt., 25, 837-847 (1986) K. Ito and T. Namioka, Rev. Sci. Instr., 60, 1573-1578 (1989)K. Ito, K. Maeda, Y. Morioka and T. Namioka, Appl. Opt., 28, 1813-1817 (1989)2) undulator based 6.65-m Eagle at BL9.02 of ALSM. Koike, P. Heimann, A. Kung, T. Namioka, R. DiGennaro, B. Gee and N. Yu, NIM, A347, 282 (1994)A.G. Suits, P. Heimann, X. Yang, M. Evans, C.W. Hsu, K. Lu, Y.T. Lee and A.H. Kung, RSI, 66, 4841 (1995)D.A. Mossessian, P. Heimann, E. Gullikson, R.K. Kaza, J. Chin and J. Arke, NIM, A347, 244 (1994)

3) 6.65-m Eagle with varibale polarization undulator at SU5 of LUREL. Nahon, B. Lagarde, F. Polack, C. Alcaraz, O. Dutuit, M. Vervloet and K. Ito, NIM, A404, 418-429 (1998)K. Ito, B. Lagarde, F. Polack, C. Alcaraz and L. Nahon, J. Synchrotron Rad., 5, 839-841 (1998)L. Nahon, C. Alcaraz, J-J. Marlats, B. Lagarde, F. Polack, R. Thissen, D. Lepere and K. Ito, RSI, 72, 1320 (2001)

Seya-Namioka monochromator (1)Seya-Namioka monochromator (1)

0,0'

,0 200200200

2200200

2

1

K

I

r

I

r

I

dFI

R/r=1.220527

R/r’=1.2169312K=69.44°

k. ito 38JASS2002Oct 21, 2002

Seya-Namioka monochromator (2)Seya-Namioka monochromator (2)1000 rays, generated from the entrance slit 10mm long, hitting the 1800-grooves/mm grating with 100(W)60(H) mm2 : from Koike’s review

k. Ito 39JASS2002Oct 21, 2002

conventional grating

holographic grating recordedwith a spherical wave front

holographic grating recordedwith an aspherical wave front

VLS grating with straight grooves

E/E3600

E/E3104

Through put: 23%

Pseudo Rowland mount monochromatorPseudo Rowland mount monochromator

Robin-Romand mount

spherical gratingof R=3m

k. ito 40JASS2002Oct 21, 2002

K. Ito, Y. Morioka, M. Ukai, N. Kouchi, Y. Hatano and T. Hayaishi, RSI, 66, 2119 (1995)

toroidal mirror

toroidal mirror

plane mirror

plane mirror

Pseudo Rowland mount monochromatorPseudo Rowland mount monochromator

nm

nmthrr

RrRrF

200

30

2

22

20cos

'

coscoscos

th is calculated by F20=0.

2 and are chosen so that

is minimized.

With a 2400-l/mm grating,E/E3104 can be attained.

k. ito 41JASS2002Oct 21, 2002

K. Ito, Y. Morioka, M. Ukai, N. Kouchi, Y. Hatano and T. Hayaishi, RSI, 66, 2119 (1995)

Off-plane Eagle (1)Off-plane Eagle (1)

6.65-m off-plane Eagle spectrograph installed at the PF in 1983

k. ito 42JASS2002Oct 21, 2002


0.1nm

0.1nm

Photographic

Photoelectric

k. ito 43JASS2002Oct 21, 2002


M1: sphericalM2: toroidalM4: cylindricalM5: cylindricalM6: toroidal

Absorbed power density

of M1 and M2 are 10.4

and 7.6 W/cm2.

Koike, Heimann, Kung, Namioka, DiGennaro, Gee and Yu, NIM, A347, 282 (1994)

k. ito 44JASS2002Oct 21, 2002

ALS


With a 4300-l/mm grating,E/E1.2105 can be attained.

VUV high-resolution beamline with variable polarization at SU5 of SACO (LURE)

20x103

15

10

5

0

Ne+

Io

n Y

ield

(c

ounts

/sec)

21.6621.6421.6221.6021.5821.56

Photon energy (eV)

Slits 20 m : FWHM (raw) = 0.22 meV R ~ 9700012d'

14s'

13d'

39s'

Autoionization spectrum of neon (4300 l/mm grating)

140

120

100

80

60

40

20

0

ion y

ield

(c

ounts

/sec)

21.612021.611821.6116photon energy (eV)

Slits : 10 mFWHM (raw) = 0.184 meVR ~ 117000

18s'

2P3/2

k. ito 45JASS2002Oct 21, 2002

Nahon, Alcaraz, Marlats, Lagarde, Polack, Thissen, Lepere and K. Ito, RSI, 72, 1320 (2001)

Monochromators Monochromators in the VUV-SX region for SR use (2)in the VUV-SX region for SR use (2)

Grazing incidence monochromators

k. ito 46JASS2002Oct 21, 2002

(E) Grasshopper monochromator: Rowland mountF.C. Brown et al., NIM, 152, 73 (1978); F. Senf et al., RSI, 63, 1326 (1992).

(A) Spherical grating monochromator (SGM) or DragonC.T. Chen, NIM, A256, 595 (1987); C.T. Chen and F. Sette, RSI, 60, 1616 (1989).

(B) SX700 (PGM, elliptical mirror) and modified SX700H. Petersen, Opt. Com., 40, 402 (1982); H.A. Padmore, RSI, 60, 1608 (1989);H. Petersen et al., RSI, 66, 1777 (1995).

(D) Harada type monochromator (PGM)T. Harada, M. Itou and T. Kita, Proc. SPIE, 503, 114 (1984); M. Itou, T. Harada andT. Kita, Appl. Opt., 28, 146 (1989).

(C) Monk-Gillieson type monochromatorM. Hettrick et al., Appl. Opt., 27, 200 (1988); M. Koike and T. Namioka, RSI, 66,2114 (1995).

SGM at the BL-16B of the PF (1)SGM at the BL-16B of the PF (1)

Change the exit-slit position to satisfy the condition of F20=0

k. ito 47JASS2002Oct 21, 2002

Shigemasa et al., JSR, 5, 772 (1998)

SGM at the BL-16B of the PF (2)SGM at the BL-16B of the PF (2)

Theoretical estimation forresolving power

N2

Ar

k. ito 48JASS2002Oct 21, 2002

Shigemasa et al., JSR, 5, 772 (1998)

SX-700SX-700

Crrr

RrRrF

'cos

cos'

cos

'

coscoscos

2

2

22

20

F20=0 with R=

C=2.25 high grating efficiency

tilting or rotation+translation

rotation

k. ito 49JASS2002Oct 21, 2002

H. Petersen, Opt. Com., 40, 402 (1982)

Modified SX-700Modified SX-700on-blaze type monochromatoron-blaze type monochromator

M. Fijuisawa, private communication

k. ito 50JASS2002Oct 21, 2002

Padmore, RSI, 60, 1608 (1989); Petersen et al., RSI, 66, 1777 (1995).

Monk-Gillieson type monochromatorMonk-Gillieson type monochromator

F20=0 at two wavelengths 1 and 2

2022

20cos

'

coscoscos mn

RrRrF

2022

20 '

coscos n

rrF

Defocus term :

R=, =1 and m=+1

F30 and F40 can be taken into account, however, it is difficult to control.

r´

rVLS plane grating

Source

Spherical mirror

Virtual image point

Spectral image point

k. ito 51JASS2002Oct 21, 2002

Hettrick et al., Appl. Opt., 27, 200 (1988); Koike and Namioka, RSI, 66, 2114 (1995).

BL-11A (1)BL-11A (1)

r=-r´ F20=0 at zeroth order and 500 eV

facilitate the optical adjustment

Kirkpatrick Baez optics

k. ito 52JASS2002Oct 21, 2002

Amemiya, Kitajima, Ohota and Ito, JSR, 3, 282 (1996); Kitajima, Amemiya, Yonamoto, Ohta, Kikuchi, Kosuge, Toyoshima and Ito, JSR, 5, 729 (1998); Kitajima, Yonamoto, Amemiya, Tsukabayashi, Ohta and Ito, JESRP, 101-103, 927 (1999).

BL-11A (2)BL-11A (2)transmissiontransmission

k. ito 53JASS2002Oct 21, 2002

BL-11A (3)BL-11A (3)NN22

absorptionabsorption

k. ito 54JASS2002Oct 21, 2002

slit widths vs. resolution/flux

Other important points in the Other important points in the construction of VUV-SX beamlines (1)construction of VUV-SX beamlines (1)

k. ito 55JASS2002Oct 21, 2002

Hardware design

Isolation of optical elements

Optical elements or optical benches are well isolated from mechanical vibrations caused by ventilators, mechanical pumps, and so on. An ideal beamline is installed on a massive concrete base.

Wavelength-scanning mechanism in monochromator: the precision of grating rotation is in the order of 1/100 sec.In-situ adjustment of optical elements, such as rotations and translation.Enclosing the important parts in a temperature controlled booth.


k. ito 56JASS2002Oct 21, 2002

Optical alignment

VUV-SX photons are not visible!!! Beam position monitors such as fluorescent screens, photodiodes, and wire monitors are needed.

Installing beamlines

Anticipate how to align beamlines in its design stage.Convenient tools for beamline alignment: theodolites and auto-levels with a telescope and a laser


Cooling systemFor VUV-SX beamlines, direct cooling is difficult! In-Ga alloy is used for better thermal contact between mirrors/gratings and their water cooled holders. Entrance slits are often required to be cooled.

k. ito 57JASS2002Oct 21, 2002

Heat load on optical elements

Thermal distortion Selecting materials with small value for as substrate of mirrors and gratings. SiC and Si are favored.

Simulation by ANSYS


Consult the makers about the micro roughness, slope error, and groove density, of optical elements, for which the beamline performance is strongly dependent.

k. ito 58JASS2002Oct 21, 2002

Specification of mirrors and gratings

Vacuum technology

Vacuum technology is well established to obtain 10-8 Pa (10-10 Torr). Clean vacuum is obtained by oil-free primary pumps.Contamination of optical elements.

cleaning with O2 discharge and UV-lamp.


k. ito 59JASS2002Oct 21, 2002

Characterization of beamlines

Photon flux, resolving power, purity of light,Reproducibility of the wavelength scanningFluctuation of the beam position on the entrance slit

Control systems of beamline PC-base control system for the monochromator including the interface boards for stepping motors and encodersBeam channel?Beamline interlock system to protect the experimentalists from radiation hazards and to avoid vacuum problems


k. ito 60JASS2002Oct 21, 2002

Safety

Radiation safety Gamma-ray stopper downstream of the first mirror, which might be installed inside a cage

Flammable and toxic gasesGas duct with a gas detection systemExhaust steam from rotary pumps

PF-2.5GeV PF-AR Ｎ KEK layout k. ito 1 JASS2002 Oct 21, 2002.

Documents

Transcript of PF-2.5GeV PF-AR Ｎ KEK layout k. ito 1 JASS2002 Oct 21, 2002.