MAC-2005Feb22-N. Ohuchi

Final Focus Quadrupole Magnet(QCS) for SuperKEKB
Norihito Ohuchi

1. QCS R&D Magnet
2. QCS Magnet-Cryostat

QCS R&D Magnet (QCS-R)

MAC-2005Feb22-N. Ohuchi

Requirement from beam optics• Integral field strength (∫G dl)
QCS-R = 11.988 (T/m)×m, QCS-L = 14.328 (T/m)×m• Location of magnet center from IP
QCS-R = 1163.3 mm, QCS-L = -969.4 mm
The compensation solenoids, ESR and ESL, overlay the QCS magnets.

• Magnet position in the perpendicular plain to the Belle axis
R 239(x, y)QCSR=(9.2, -0.3), (x, y)QCSL=(21.2, 0.2)

R 219

ESR

The axes of the compensation solenoids
are coincident with the Belle axis.

QCSR
R 116.1

R 90
R 69
R 77
R 80

R 50
R 85
R 72e+

R 90
9.2eR 136
R 137

R 147
R 164

R 85
R 209

R 194

R 186
R 194
R 176

QCS R&D Magnet (QCS-R)

MAC-2005Feb22-N. Ohuchi

Magnet parameters•••••

6 layer coils (3-double panecake coils)
Inner coil radius : 90.0 mm
Outer coil radius : 116.8 mm
Cable size : 1.1mm × 4.1mm
Number of turns : 271 in onepole
1st layer = 38, 2nd layer = 39
3rd layer = 46, 4th layer = 47
5th layer = 50, 6th layer = 51

••
•
•
•

Field gradient : 40.124 T/mMagnet current : 1186.7 A
Magnetic length : 0.299 m
Inductance : 69.98 mH
Stored energy : 49.3 kJ

S.C. coil temperature rise< 60 K

Normal transition(Quench)

Rin=90 mm

QCS R&D Magnet (QCS-R)

MAC-2005Feb22-N. Ohuchi

Magnetic field calculation (field quality)
170 mmQCS R&D Magnet (QCS-R)••

6th layer

Multipole components in 2-D calculation (magnetcross section) @ Rref = 50 mm
b2=10000, b6=0.12, b10=-0.04, b14=0.12

5th layer

Integral multipole components(including magnet ends) @ Rref = 50 mm∫b2dl=10000, ∫b6dl=-0.04, ∫b10dl=0.46, ∫b14dl=0.02

4th layer
3rd layer

QCS-L•

Integral multipole components(Length of the magnet straight section=228.3mm)@ Rref = 50 mm∫b2dl=10000, ∫b6dl=-0.02, ∫b10dl=0.38, ∫b14dl=0.04

2nd layer
1st layer

450 mmQCS R&D Magnet (QCS-R)

MAC-2005Feb22-N. Ohuchi

bn@lp=(Bn @lp /B2@mag-center)×10000

Field profile along beam line

QCS-R&D-C8v3.4fft

1.2 104
1 104

b2

8000

Calculated integral b6, b10, b14b2

•

6000

b2 @lp4000

MagnetStraight
Section2000∫b6dl = -0.04, ∫b10dl=0.46, ∫b14dl=0.02

Physical Magnet Length

0-2000

50
b6

Max.

b6 @lpb6

Peak of b6 @lp, b10 @lp, b14 @lpMin.

0-25-50

b6 @lp41.8-41.6

43b102b14 @lp

3.48
0.126-3.23

1b10 @lp

b10b10 @lp-0.252

0-1-2-3-40.2
b140.1b14 @lpb14•

250-0.1-0.2-0.3-40-30-20-100

10Position, cm

203040QCS R&D Magnet (QCS-R)•Field Profile along the magnet length
at r= 90 mm, θ= 46 degree

QCSR, operated independently

6–

Max. field in the coil = 4.56 T @1186.7A–

Iop / Ic =72.6%

QCSR, operated with ESR–

Max. field in the coil = 5.97 T @1186.7A–

Iop / Ic =83.6%

QCSR, operated with ESR and Belle–

Max. field in the coil = 4.99 T @1186.7A–

Iop / Ic =75.1%

QCSR-field-profile

QCSR, T
QCSR-B with ESR1, ESR2, T
QCSR-B with ESR1, ESR2, Belle, T

5432

10-30-20-100102030z, cm
QCSR-SC-dat.MAC 9:16:44 PM 05.2.17

8ESR

S.C. cablecritical line
at T=4.7 K

7046.

QCSR

0°
r=90.0(9.2,-0.3)

r=94.2

QCS magnetic field, T•

Max. field in the coil
Magnetic field strengthT•

MAC-2005Feb22-N. Ohuchi

654QCS, T
QCS+S, T
QCS+S+Belle, T
4.7K

32I=1186.7 A

1005001000

1500

QCS magnet current, A

2000

2500

MAC-2005Feb22-N. Ohuchi

QCS R&D Magnet (QCS-R)
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QCS R&D Magnet (QCS-R)

MAC-2005Feb22-N. Ohuchi

MAC-2005Feb22-N. Ohuchi

QCS Magnet CryostatIPRequirement from the Bellegroup
pointed by M. Sallivan in 6th HLWS, 2004
reported by O. Tajima in this meeting

969.4

ESL-2
30.00°

ESL-1

QCSL

21.2– Redesigning cryostat configuration
to reduce the Rad. Bhabha BG

QCSL-CENTER(z-direction)

500•

QCSL-CENTER(H)Introducing the heavy metal (Tungsten alloy) as
one of the magnet structural materials.

97W-4Ni-1Cu
Necessary to modify the support system of theliquid helium vessel
130

ESR and ESL solenoids were calculated again,
and the fronts of the cryostats were re-designed.
The created space in radial direction :25 mm for ESR
38 mm for ESL

QCS-CENTER

1163.3

ESR-2
17.00°– Increasing the space between thedetector and the cryostat for wiring
the cables

85

ESR-1

QCSR

MAC-2005Feb22-N. Ohuchi

QCS Magnet-Cryostat•

Tungsten alloy (97W-4Ni-1Cu)– Density = 18.5 g/cm3, Non-magnetic material.

••

Weight of the components in the magnet-cryostat
Right, kg

Left, kg

Helium Vessel

234

202

QCS

135

157

ES

90

48

Correctors

33

44

B.G. shield (97W-4Ni-1Cu)

116

145

Total

608

596

EMF induced by the interaction with the Belle detector and the ES-magnets– EMFESR = 2.2×104 N , EMFESL = 4.8×104 N

MAC-2005Feb22-N. Ohuchi

QCS Magnet-Cryostat
Design of the support system•

The liquid helium vessel is supported with eight rods.
– The material of the rod is a titanium alloy (Ti-6Al-4V, ELI).
The titanium alloy has half thermal conductivity of the stainless steel from 77 K to 300 K.
The yield strength of the titanium alloy is 1.5 times larger than that of the SUS316LN at 300 K.

•••

The rods are designed to stand EMF and G.
They are designed not to change the center of QCS against the thermal
contraction by cool-down.
The heat load via these support rods must be within the refrigerator capacity.
300 K

4.7 KEMF

W

Liquid Heliumvessel
4.7 K
Vacuum vesselroom temp.

MAC-2005Feb22-N. Ohuchi

QCS Magnet-Cryostat
Modified support system
Left

Right

Rod diameter, mm76Rod length, mm

6565

Distance between rods, mm

650

800

Max. force through one rod, N

1.16×1048.19 × 103

Stress, N/mm2306

290

Allowable tensile stress at R.T., N/mm2400400

Heat load via one rod, W

0.24

0.18

Total heat load (eight rods), W

1.92

1.44

44.
810

°

300 K300 K

80 K65029.3

24°80 K

4.7 K

4.7 K800

ESR-2

ESL-1

QCSL

ESR-1

QCSR

MAC-2005Feb22-N. Ohuchi

QCS Magnet-Cryostat
ESR-1 and ESL-1 parameters

ESR-1

ESL-1

Previous design

Present design

Inner radius, mm

82.3

82.3

Outer radius, mm

91.1

95.5

Coil length, mm

150

100Winding, turns × layer

75 × 850 × 12Max. field without Belle, T

3.27

4.26 ( 75.3% @ 4.7K)

Max. field with Belle, T

2.14

2.76 ( 62.8% @ 4.7K)

Magnet current, A

619

647.2

Previous design

Present design

Inner radius, mm

77

77

Outer radius, mm

92.4

94.6

Coil length, mm

166

166

Winding, turns × layer

83 × 1483 × 16

Max. field without Belle, T

4.98

5.83 ( 92.4% @ 4.7K)

Max. field with Belle, T

3.49

4.33 ( 80.0% @ 4.7K)

Magnet current, A

619

656.2

MAC-2005Feb22-N. Ohuchi

Summary The 3-D field calculation of the QCS R&D magnet has been completed.
– Integral multipole components (including magnet ends) @ Rref = 50 mm∫b2dl=10000, ∫b6dl=-0.04, ∫b10dl=0.46, ∫b14dl=0.02

 The designs of the magnet components and the tools for construction are almostcompleted. They will have been machined until the end of this March.
 For shielding the Rad. Bhabha BG, application of the heavy metal was studied as thematerial of the magnet components in the cryostat. The heavy metal does not have alarge effect on the cryostat design at LHe temperature.
 In order to make space for wiring the cables from the detector, the fronts of thecryostats and the compensation solenoids, ESR-1 and ESL-1, were re-designed.

3-D calculation results with the Belle field
QCSR

QCSL

ESR-1

ESR-2

ESL-1

ESL-2

Iop, A

1186.71186.7

647.2

647.2

656.2

656.2

Max. field, T

4.99

4.77

2.76

2.61

4.33

2.93

Iop / Ic, %

75

74

6360

8056