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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)
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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
Beam swinger For the angular dependence measurements, the incoming beam direction is changed instead of the outgoing particle direction. configuration: DQQD bending: -45 and +135 deg designed by H. Shimizu pre-assembling at manufacturer’s factory
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. effect of rotator S(q ) invert-rotator T(q )
Graphical understanding of the invert-rotator T(q ) before inversion after inversion is easy to obtain and is not inferior to as a rotator.
How to make a vertical inverter Q-triplet is an incomplete inverter because we cannot specify *’s. Q-septet is a complete inverter. A Q-septet rotated by q /2 can rotate the beam image by q after vertical inversion. reference: S. Kato, Nucl. Instr. & Meth.A254(1987)487
Asymmetric quadrupole magnets between horizontal and vertical directions Q3 Q1 left halves: field line curves right halves: field strength contours (convenient for Q-magnets) Q2 Bottom yokes of Q1 and Q2 are open for the beam dump.
Quadrupole magnets before installation Q3 (left) and Q2 (right) Q1 magnet being painted
Performances reference: T. Ichihara et al, Nucl. Phys. A569(1994)287c
Farewell to SMART 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 I would like to express my thanks to the collaborators