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
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