Design and construction

plantcitybusinessUrban and Civil

Nov 26, 2013 (4 years and 1 month ago)

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Design and construction
of SMART

Presented by Seigo Kato

Nov. 12, 2005

http://www.quark.kj.yamagata
-
u.ac.jp/~kato

Characteristics of a fixed
-
angle spectrometer

Advantages


cascade mode


selectable resolution


future extension (3
-
rd dipole)


zero
-
degree measurement (beam stop at first stage)


trace back to the target by double position detection


no need of rotation mechanism and space


heavy shield for detectors


neutron TOF


Disadvantages


need of beam swinger


need of arbitrary
-
angle twister


beam dump

to be discussed in this report

Layout of the experimental halls

The concrete is

not strong
here.

Selectable resolution



41 %
20 msr
1/4000

4 %
10 msr
1/13000

Possible extension:

a super
-
high
-
resolution mode

Ray
-
tracing

Beam swinger

For the angular dependence measurements, the incoming beam direction is
changed instead of the outgoing particle direction.

pre
-
assembling at manufacturer’s factory

configuration: DQQD

bending:
-

45 and +135 deg

designed by H. Shimizu

Arbitrary
-
angle beam twister

Because the direction of the dispersion in the beam swinger has to be
within the median plane, we need a beam image rotator for
arbitrary
angles.

























































)
sin(
)
sin(
)
cos(
)
cos(
sin
sin
cos
cos

cos
0
sin
0
0
cos
0
sin
sin
0
cos
0
0
sin
0
cos
'
'
)
(





















B
A
B
A
B
A
B
A
y
y
x
x
S
effect of rotator
S
(

)





























1
-
0
0
0
0
1
-
0
0
0
0
1
0
0
0
0
1

)
(
cos
0
sin
0
0
cos
0
sin
sin
0
cos
0
0
sin
0
cos
)
(










S
T
invert
-
rotator
T
(

)

before inversion

after inversion

Graphical understanding of the invert
-
rotator T(

)

is easy to obtain and is not inferior to

as a rotator.
















1
*
0
0
0
1
0
0
0
0
1
*
0
0
0
1

3
Q
Q
-
triplet is an incomplete inverter because we cannot specify
*
’s.

A Q
-
septet rotated by

⼲/捡渠牯瑡瑥瑨攠
扥b洠業m来⁢y


慦瑥爠r敲瑩捡氠楮v敲獩潮.

)
0
(
1
0
0
0
0
1
0
0
0
0
1
0
0
0
0
1

T
Q
7
















Q
-
septet is a complete inverter.

reference: S. Kato,
Nucl. Instr. & Meth.

A254
(1987)487

How to make a vertical inverter

Asymmetric quadrupole magnets between
horizontal and vertical directions

Bottom yokes of Q
1

and Q
2

are open for the
beam dump
.

Q
1

Q
2

Q
3

left halves:


field line curves

right halves:


field strength contours


(convenient for Q
-
magnets)

Quadrupole magnets before installation

Q
1

magnet being painted

Q
3

(left) and Q
2

(right)

Total system installed

reference: T. Ichihara et al, Nucl. Phys. A569(1994)287c

Performances

What was SMART for me from technical viewpoint?

A big challenge to overcome many problems


Hints to subsequent spectrometers


QQD spectrometers such as BBS, HKS, HES


fixed spectrometer proposed for GSI eA
-
collider

Farewell to SMART

I would like to express my thanks to the collaborators