The 11th Symposium on Accelerator Science and Technology, Harima Science Garden City, 1997

Magnet Alignent Results of the SPring-S Storage Ring
Sakuo MATSUI, Chao ZHANG, Koji TSUMAKI, Jun-ichi OHNISHI, Kiyomitsu HASEGAWA,Yasushi SASAKI, Xin OUY ANG, Yutaka CHIDA and Yasuyuki OKADA
SPring-8, Kamigori, Akoh, Hyogo, 678-12 JAPAN

Abstract
The magnets alignment of the SPring-8 storage ring wascompleted at May 1996. After one year relative values
between the girders was 0.05 mm in horizontaHy and0.06mm in vertically. The deviation of multipole magnets
from the straightness was about 20jlm in a girder.

shifted values of girder were larger than expected. Transverse
relative deviation (1 cr) between girders changed as follows:
1996.3
1996.10
1996.111997.2

1. Introduction
The storage ring has 1436m circumference whichsurrounds the 50m-high hill. Each cell has 10 quadrupoleand 7 sextupole magnets on 3 girders, and 2 bendingmagnets.
Twenty-one monuments in whole ring were surveyed
before tunnel construction with a distance meter (KernME5000) and two ceodlites (Wild T3000). Thesemonuments were used as reference points. After tunnel
construction these monuments and other 67 ones weresurveyed by laser tracker (Leica SMART 310) and theceodlites by making network. The marks for baseplates weremade by the laser tracker. After this the girder was set on
the baseplates and multipole magnets were put on thegirder.
Two target stages have been fixed after fine adjust at the500.00mm above the magnetic axis at magnetic fieldmeasurement on both end magnets as shown in Fig. I.

40 jlm just after alignment
56
40 After 27 out of 144 girders adjust
45 (Fig.2) (1997.3 ring commissioning)Fig.2 is obtained by a distance and angle combined
survey. Vertical lines represent error bars of the absolutedisplacements. Angular measurement between girders isnecessary to reduce transverse displacement as a whole, but
it does not affect relative positions between girders in ourcase. One can see that displacement in radial direction is 1.4mm maximum for the ring and 0.37 mm on average.

e~s;:;
..,
8..,
1!0.

1.00.0l5

Fiducial Points for alignments between girders and on a girder

Fixed stage'j_ Refere!!~-f~'!'~- a girde!

\ Fixed stage"'
800Point

Fig.2 Horizontal transverse displacements of girders.

2.2 Circumference measurement
The laser tracker was used to measure the circumference.
The result was 1.9mm(1.3ppm) longer than designed value,
and the one calculated from RF frequency was 2.2mm.

Fig. I. Alignment reference line and magnetic pole axis.
After pre-alignment both the end magnets were surveyed
by the laser tracker, and then girders were smoothed.
Bending magnets were aligned using these alignedpoints.
Five or seven multipole magnets on the girder werealigned precisely using a laser and CCD camera system andtiltmeters (Taylor Hobson Talyvel4).

2. Alignment between girders

2.1 Horizontal plane
Since the girder number is 144, survey points are 288.
After first alignment, the multipole magnets were halfdivided and restored to install vacuum chambers. Vacuumchambers were baked, which supports are mounted on thesame girder as magnets. Temperature was not uniform in
the period of magnet installation, maximum 15 degreechange. The girder is fixed to the baseplates at 6 legs. Since
the length is 4 or 5 m, thermal expansion is large. Thus the2.3 Vertical
Magnet levels were surveyed four times. Fig. 3 shows thechanges between the two surveys and the last level. Thelevel difference between far apart two points is not reliable.
The elevation at the 10 m long underpath for vehicle rose
up to a maximum of 0.4 mm during the summer anddecreased by 0.4 mm during the winter because of ambient
temperature changes. The floor levels over undergrounddrain pipes of 0.9m diameter at five locations changed from±0.1 to ±0.2 mm in the same way. Since both ends of thispipe were opened in the air, the floor over the pipe section
was warmed and cooled. There are two points which change
reason is unknown.
The floor over the RF wave guide room settled and is now
deforming depending on the temperature in that room.
The length of the section over the transport line fromsynchrotron to the storage ring (SSBT) is about 7 m. The
concrete thickness of this floor is 1.4 m. The floor levelchange of this area was within 0.2mm.

-44-The 11th Symposium on Accelerator Science and Technology, Harima Science Garden City, 1997

O=Drain Pipe

0.4'E
5 0.2

~=under floor wave guide

0.40.2"Es0.0~~-0.2-0.40SSBT

I0Fig.3. Level changes and the last level of the girders.

3. Alignment of bending magnet
25

Bending magnet were aligned with the laser tracker andtiltmeters(Leica Nivel 20) put on two fiducial planes. Thesebending magnets are pulled to down-stream direction
remarkably by the vacuum force (800kg) which comes fromthe asymmetric cross sections of the bellows. Thus theaverage value of s-directional displacements was 0.26mm
shown in Fig.4. Eight magnets were re-adjusted. Since thestress point is edge of the magnet, the magnet rotates(Fig.5) and slightly twists. (Fig.6)
The fiducial plane inclined for 140 J.lfad by magnetic
force. Thus it was better to take account of this whenaligning.
25

Displacement (S direction)'":"'~ci-.a:t/1

Displacement(mm)Ring outslde o~

Fig.5. Transverse displacements of bending magnet.

Bending Magnet

20
Average=0.26mm
u=0.18mm~W~~MN-9 9 9 9 9 9 90-NMddd•d~d~d~dlilt (mrad)

av=-0.07 u •0.05"""" av=+O.Ol u =0.06
o.,., av-·0.04 u =0.05
Upper av•~0.01 a =0.05

Displacement(mm)Fig.4. S-directional displacements of bending magnet.

-45-Fig.6. Tilts of fiducial planes of bending magnets.

The 11th Symposium on Accelerator Science and Technology, Harima Science Garden City, 1997

100.0

80.0
60.0
40.0
20.0~

0.0.3 -20.0~ --40.0-60.0,.

I..• II llh n.ttUd IIJ

IW111i'l\fMblI'~"'lrFI

I'IfIllJLAl!ll j li 1 11HtUUI lii1
1"1 1\tltlm
I l¥1IIIllUII~'IIIll II\IW\111f"'ll300

IIII!

i,I~ IW!

flJ11a' IIIII!
I II

Tilt of fiducial plane

zso
~ zoo

average-0.8 urad
u•31 urad~ 150~ 100
500r~ ~-80.0000~ ~ ~ ~ ~2 ~ ~·~ g 0 g ~0Tilt( urad)·100.0

Fig.7. Tilts of all multipole magnets.
140

4. Alignment in a girder

Displacement(S direction)

120

Quadrupole and Sextupole magnet

Average=-O.OSmFig. 7 shows the whole ring tilt of fiducial planes of E 100
a=0.29mm
f! 80
multipole magnets in July 1996. The reproducibility of Cl0
fiducial plane tilt was not good for the two types of .... 60~
quadrupole magnets after divide and restore. Thus the40
fiducial plane tilt which exceeds 80 j.l.rad does not agree20with the magnet tilt. Fig. 7 also suggests that the floor tilt
0changed after alignment. Fig.8 shows the tilts histogram ofco<D0Nv<Dco":!
c::i c::i c::i c::i9 9fiducial planes.
·Displacement(mm)The standard deviation of alignment error in a girder were .
about 6 J.l.m in horizontal and vertical directions just afterFig.ll. S-directional displacements of multipole magnets.
the alignment. However after divide and baking etc., thedisplacements also got worse.(Fig.9,10).
4.1 Thermal Deformation
The distribution of s-directional displacement was notgood because a tape measure was used when aligning theThe girder and magnets expand as temperature, There aremagnets.(Fig.ll)
many cables under the girder. Fig.12 shows the changes ofthe vertical displacements by current flow. The reference
points are both end magnets in a girder. This figure shows80
the middle magnets rise up about 10-30 J.l.m at 1.7m level.
Horizontal Displacement
~

07060
~ 50
g 4oso. .-----~~----------~-------------­
Vertical Change

average=71Lm
a=171Lm(during electric current flow- no current)40.

e-.3 30.

~ 3020§ 20. ~----------+-~--~---------+~--~~

1 ~ ~--~~~~~uu-.~-.~~.uLR~~~~ ~~~~~~~,~~;~;~~o~~~2~~~~~~~g~R

10.

~~~~~~~~~~~. .~-,~~r-t--t

0.~_.~--~~----4~._~~~~~-.~--~

Displacement( IL m)-10. L __________________________________ _Fig.9. Horizontal displacements of multipole magnets.

8~~&~8dd~~8~~&~Sdd8~&~S,.... ,.... c1 co co oo co co co co co co cJ en cn en cn cn en en o~o

88~888888888~8888888uuuu(}

80

Fig.12. Thermal deformation in a girder.

Vertical Displacement

70s. Concluding Remark

60~ 50g 40

average=-71Lm
a=161Lm~ 30
20
100 ~~~LR.U~ad~a.~-.~~.w~~~~~
Displacement( IL m)

Fig.lO. Vertical displacements of multipole magnets.

It is not desirable that there is some space under the floor.
The obvious floor level changes in the improved
foundation area (about 30%) cannot be detected now.
It is most important to survey and adjust the girder under
the same temperature, if possible operating temperature.
It is not good that the vacuum force pulls the magnet.
The thermal effect especially by current flow is important
for the alignment in a girder.

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