Optimization of a Dipole with Partially Keystoned Cable for the SIS 300

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Optimization of a Dipole with Partially Keystoned
Cable for the SIS 300

• L. Tkachenko, IHEP, Protvino

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Requirements to the SIS 300 dipole
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Conditions of optimization
2D

• Minimization of heat losses

• Suppression of b3, b5, b7, b9, b11

3D
Suppression of

•  

• Minimization of field enhancement in end parts

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Characteristics of superconducting wire
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Cable
Like the existing LHC dipole outer layer cable
36 strands, 25-µm stainless steel core
The cable is insulated by 3 layers of polyimide
film, with an effective cured insulation
thickness of 125 µm in the radial direction and
95 µm in the azimuth direction
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Material for iron yoke

• HC, A/m
• 70
• M250-50 30

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Cross section
b3 0 b5 0 b7 0 b9 0 b11 0
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b3 0 b5 0 b7 0 b9 0 b11 0
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Comparison of two geometries
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Production tolerances, µm
?B lt 510-4, ?bn lt 210-4, dl Rm df
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?C 30 mm
dx dy lt 50 µm
Cross-section of dipole 1 coil, 2 - wedges, 3
key, 4 collars, 5 slot, 6 iron yoke, 7
stainless steel shell, 8 - hole for II-phase
helium.
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Optimum parameters for suppressing
RHe 35 mm
?Fe 143.5 mm, 2212
?Fe 144.5 mm, M250-50
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Field quality
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Values of integrals , 10-4
Maximum variations of the transfer function and
multipoles b3 and b5 (peak-to-peak)
n 2212 M250-50
3 -0.02 0.06
5 -0.11 -0.20
7 -0.26 -0.32
9 0.36 0.36
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Heat losses/cycle
Field cycle 1.6 T 6.0 T 1.6 T Time cycle
4.4 c 11 c 4.4 c
Coil
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Iron yoke
Specific losses
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Temperature margin
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3D geometry
n1
Additional spacers
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Dependences of two lower non-zero multipoles of
integral field versus turn number n1 in the first
block of the inner layer.
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Geometric length of dipole versus shifted number
of turns for magnetic length Lm 2600 mm (µ ?)
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Maximum field in the end parts versus iron
shortening for different n1. Horizontal line
shows maximum field in the coil in the 2D cross-
section.
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Geometric length of the coil at Lm 2600 mm
versus n1 for two steels.
Steel 2212 n1 7, ?LFe 178.5 mm, Lg 2774.3
mm
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Conclusion
This work presents optimized 2D and 3D geometries
for the SIS300 dipole. With such data, a magnet
technical design could begin. The advantages in
magnetic properties of 2212 steel, in comparison
with M250-50 steel, are also shown. Additionally,
in spite of lower losses in the magnet yoke with
M250-50 steel, 2212 steel provides a higher
temperature margin, thus ensuring better
stability of the magnet.