IR Magnets
SuperKEKB
N. Ohuchi
KEK(on behalf of KEK SC magnet group, IR group and BNL SC magnet group)

2012/02/20

SuperKEKB MAC 20121

Contents
1. Progress from the last MAC
2. IR Magnets Overview
3. Design of S.C. magnets
4. R&D status
5. Construction schedule

2012/02/20

SuperKEKB MAC 20122

Progress from the last MAC
1. IR magnet design–––––

Introducing iron Yoke for QC1Es and QC2PR
Reducing the number of coils for cancelling the leak field
The coil 3D designs of QC1 and 2 and evaluation in the beam optics
Redesigning compensation solenoid and iteration of the design against
opticsResearch collaboration work for correctors and cancel coils with BNL

2. R&D–––

Completing QC1P R&D magnet and cold test
Vibration study and measurement
Harmonic coil for field measurement

3. Cryogenics–

Building the LHe‐sub‐cooler, overhaul of He compressors

2012/02/20

SuperKEKB MAC 20123

IR Magnets Overview

QC2LE+ correctors

QC1RP + QC1RE + QC2RP QC2RE+ correctors
Correctors + cancel coils Two solenoids
Solenoid

QC1LP + QC1LE + QC2LPCorrectors + cancel coils
Solenoid

LERIPHER
Magnet‐cryostat in the left

2012/02/20

Magnet‐cryostat in the rightSuperKEKB MAC 2012

4S.C. Magnets in SuperKEKB IR
Design changes in the magnets: introducing iron yokes to the quadrupoles and magnetic
shields on the beam pipes
QC2RE
QC2LP

QC1RE

QC1LP

QC1RP
QC2LE

IRON IRON

QC2RP

QC1LE

IRON

Integral field gradient, (T/m)・m
Solenoid field, T

Position fromIP, mm

Magnet type

Corrector

QC2RE

12.91 [34.9 T/m × 0.370m]

2925

S.C. + Iron Yokea1, b1, a2, b4

QC2RP

10.92 [27.17 × 0.4135]

1925

S.C. + Iron Yokea1, b1, a2, b4

b3, b4, b5, b6

QC1RE

24.99 [66.22×0.3774]

1410

S.C. + Iron Yokea1, b1, a2, b4

b3, b4, b5, b6

QC1RP

22.43 [66.52×0.3372]

935

S.C.

a1, b1, a2, b4

b3, b4, b5, b6

QC1LP

22.91 [67.94×0.3372]

‐935

S.C.

a1, b1, a2, b4

b3, b4, b5, b6

QC1LE

26.67 [70.68×0.3774]‐1410

S.C. + Iron Yokea1, b1, a2, b4

b3, b4, b5, b6

QC2LP

10.96 [27.15 × 0.4135]‐1925

S.C. + Iron Yokea1, b1, a2, b4

QC2LE

14.13 [20.2×0.700]‐2700

S.C. + Iron Yokea1, b1, a2, b4

ESR

4.3 T (max. field)

ESR‐add

0.3 TESL
2012/02/20

4.7 T (max. field)

Leak field cancel
coil

S.C. Solenoid
Each beam

S.C. Solenoid + Iron Yoke

S.C. Solenoid
SuperKEKB MAC 2012

5

QC1P (No iron yoke)
Original design
Need to be modified

QC1Pe+e‐

SC correctors
a2, b1, a1, b4

QC1P magnet design (QC1RP, QC1LP)•••

Same design for QC1RP and QC1LP
2 layer coils [double pancake]
SC correctors [design changed by thediscussion with BNL]––••SC cancel correctors
b3, b4, b5, b6

SC cancel coils against the leak field from QC1P
• b5, b6, b4 , b3 from the inside• Cryostat inner bore radius=18.0 mm• Beam pipe(warm tube)–

inner radius=10.5 mm, outer radius=14.5 mm

a2, b1 and a1 inside of the magnet bore
b4 outside of the magnet collar

Cryostat inner bore radius=18.0 mm
Beam pipe (warm tube)– inner radius=10.5 mm, outer radius=14.5 mm
2012/02/20
SuperKEKB MAC 2012

6QC1R/LP Magnet Parameters
QC1RP

QC1LP

Coil inner radius, mm

25.00

Coil outer radius, mm

30.485

Turns in one pole

QC1P operation point

12 (1st layer), 13 (2nd layer)

Spec. of integral field, T

22.43

22.91

Field gradient, T/m

66.52

67.94

Effective magnetic length, m0.3372

Magnet current, A

1575.58

1609.30

Current density of the cable (SC area), A/mm2

1685.01721.0Current density of the cable (overall), A/mm2802.4

819.6

Magnetic field by Belle and comp. sol., T

2.5

2.5

Max. field in the coil without solenoid field, T

2.29

2.34

Max. field in the coil with solenoid field, T

4.07

4.08

Operating point with respect to Bc at 4.7 K

81.8%

83.5%

Magnet physical length, mm

416

Error field at r=1 cm (2D calculation)b6 = 1.60 × 10‐5b10 = ‐2.28 × 10‐6
b14 = 6.20 × 10‐7Error field at r=1 cm (3D calculation)b6 = ‐1.13 × 10‐5b10 = ‐4.71 × 10‐6

2012/02/20

SuperKEKB MAC 20127

3D Magnet Design of QC1R/LP
QC1LP and QC1RP have the same design.
384

2nd layer

Mirror symmetry for
reducing the skew
quadrupole field in thelead end.

Lead end

1st layer

Return end

All magnet components, like end spacers and collars, have been designed.
2012/02/20

SuperKEKB MAC 20128Field profile of QC1R/LP
QC1LP and QC1RP have the same design.

Multipole field at R=10 mm
Integral b4 = 1.76 × 10‐5Int. b6 = 6.31 × 10‐5Int. b8 = 1.07 × 10‐6
Peaks of B4 = ± 6 Gauss at 1000 A(= ± 9.6 Gauss at 1600 A)
Peaks of B6 = + 2.8 Gauss at 1000 A(= + 4.5 Gauss at 1600 A)

Lead End
2012/02/20

Return End
SuperKEKB MAC 2012

9

QC1E with Iron YokeSC cancel correctors
b3, b4, b5, b6

QC1E withoutiron yoke
(OLD DESIGN)SC correctors
a2, b1, a1, b4

QC1E with ironyoke(NEW DESIGN)

Magnetic shield (iron)

SC correctors
a2, b1, a1, b4

IRON YOKE
2012/02/20

SuperKEKB MAC 201210

QC1E magnetic field calculation in 2D

QC1E magnet design (QC1RE, QC1LE)•••

2 layer coils [double pancake]
Magnet inner bore radius=33.0 mm
Beam pipe (warm tube)–•

Magnet current= 1655 A–•••

Inner radius=17.0 mm, outer radius=21.0 mm
Current density = 599.6 A/mm2 (in the coils), 1770 A/mm2 (in NbTi)

GR = 75.94T/m
Maximum field in the magnet=2.89 T
Ratio of field enhancement by iron is 1.338.
2012/02/20

SuperKEKB MAC 201211

QC1E Operation Point
QC1RE
G=66.22 T/m
Iop=1460.3 A
Jop=1561.8 A/mm2
Jop/Jc@4.7K=67.3 %QC1E load line

QC1LE

QC1LE
G=70.68 T/m
Iop=1558.5 A
Jop=1666.9 A/mm2
Jop/Jc@4.7K=71.8 %QC1RE(Leff= 0.3774 m)
In case that the operating pointof 85 % w.r.t. the critical point is
acceptable, the quadrupole field
can be increased by 18 %.

2012/02/20

SuperKEKB MAC 201212

3D Magnet Design of QC1R/LE
QC1LE and QC1RE have the same design.

430

2nd layer

Mirror symmetry for
reducing the skew
quadrupole field in thelead end.

1st layer

Lead end

Return end

All magnet components, like end spacers and collars, have been designed.
2012/02/20

SuperKEKB MAC 201213

Field profile of QC1R/LE

Multipole field at R=15 mm
Integral b4 = 2.48 × 10‐6Int. b6 = 7.22 × 10‐5Int. b8 = 4.33 × 10‐6Max. B4 = + 4.3 Gauss at 1000 A(= + 7.3 Gauss at 1700 A)
Max. B6 = + 8.3 Gauss at 1000 A(= + 14.1 Gauss at 1700 A)

Lead End
2012/02/20

Return End
SuperKEKB MAC 201214

QC1, 2 Magnet Parameters
Iron Yoke

Magnet current (A)Field gradient (T/m)

Effective length (m)Operating point(%)

QC1RP

No

1575.666.52

0.3372

82

QC1LP

No

1609.367.94

0.3372

84

QC2RP

Yes

817.9

27.17

0.4135

41

QC2LP

Yes

817.3

27.150.4135

41

QC1RE

Yes

1460.366.22

0.3774

67

QC1LE

Yes

1558.570.68

0.3774

72

QC2RE

Yes

1044.930.59

0.4221

55

QC2LE

Yes

724.1

22.07

0.640732

2012/02/20

SuperKEKB MAC 201215

Evaluation of magnetic field by optics cal.

Calculation by Oide‐sanCryostat in the right side
QC1RE
IP
QC1RP
Lead end
2012/02/20

return end

QC2RP
Lead end

SuperKEKB MAC 2012

return end
16

S.C. Correctors• All correctors and the leak field cancel coils will be manufactured
by BNL under the international research collaboration.
• QC1 and QC2 quadrupoles have SC correctors of a2, b1, a1 and b4.
SC wire is wound in coil with thedirect winding method.
QC1P b1コイル

31 turns/pole
B1=0.045 T at 50A
Iop/Ic= 68 % at 5.0 K

QC1P b4コイル

8 turns/pole
B4=3398 T/m3 at 50A
Iop/Ic= 68 % at 5.0 K

2012/02/20

SuperKEKB MAC 201217

SC corrector design status
G(T/m)

Corrector
Current
(A)

A1(T)

B1(T)

A2(T/m)B4(T/m3)dy(mm)

dx(mm)dθ(mrad)

QC1RP

66.52

50

0.045

0.046

2.28

33980.657

0.632

14.0

QC1LP

67.94

50

0.045

0.046

2.28

3398

0.644

0.618

13.7

QC2RP

27.17

50

0.07920.0785

1.253

442.4

2.91

2.89

23.1

QC2LP

27.15

50

0.07920.0785

1.253

442.4

2.92

2.89

23.1

QC1RE

66.22

50

0.067

0.130

1.770

1853.61.01

1.955(0.69:Optics
1.265:alignment)

13.4

QC1LE

70.68

50

0.067

0.130

1.770

1853.60.95

1.839(0.69:Optics
1.159:alignment)

12.5

QC2RE

34.90

50

0.07950.0783

1.137

327.6

2.28

2.24

16.3

QC2LE

20.20

500.0795

0.0783

1.137

327.6

3.94

3.88

28.1

2D calculations of SC correctors have been completed.
3D design of the corrector coils for QC1P has been completed, and the other coils
are evaluated under the condition that the coils have the same effective magnetic
length as the main quadrupole.
2012/02/20

SuperKEKB MAC 201218

Cancel Coils for QC1P Leak Field•••

QC1P for the e+ beam line is non‐iron magnet and the e‐ beam line is very close to QC1P. The leakfields along the e‐ beam line by QC1P are calculated.
B3, B4, B5 and B6 components of the leak fields are designed to be canceled with the SC cancel coils.
B1 and B2 components are not canceled, and they are included in the optics calculation.
–B2 component is used for focusing and defocusing the e‐ beam.

QC1RP leak field profile
along the e‐ beam line

2012/02/20

SuperKEKB MAC 201219

b3 Cancel Coil Configuration
2nd layer

1st layer

2012/02/20

SuperKEKB MAC 2012

Sextupole coil array

20

Canceling QC1P Leak Field
Leak field (T)Cancelling the leak fields by SC multipole coils

b4b3Distance from IP (m)b6b5

2012/02/20

SuperKEKB MAC 201221

Compensation Solenoids• Magnetic design of compensation solenoids with iron components– By introducing iron components on the beam lines, the solenoid profile was changed.

Without iron components(the model in the last meeting)With iron components

2012/02/20

SuperKEKB MAC 201222

Compensation Solenoids (cont.)• Initial magnet configuration–•Optics calculation–•In order to cancel the residual solenoid field between QC2RP and QC2RE, we placed 1.5 T additional solenoids
behind QC2RE on each beam line.
This configuration reduced the LER beam life time from 570 s to 400 s. By reducing the peak field of the solenoidfrom 1.5 T to 0.2 T, the life time recovered to over 540 s. The optics calculation showed that the solenoid field bump
between QC2RP and QC2RE had a small impact on the life time.

Improving the solenoid design–

Additional solenoid : Solenoid field = 0.3 T, length = 0.7 m inside of the QC2RE yoke.

Additional solenoids
2012/02/20

SuperKEKB MAC 201223

Compensation Solenoids (cont.)
Additional solenoid and iron yokeESLESR

Solenoid field profile

0.615T

0.301T
Length of solenoid= 0.7 m••

In order to force the integrated solenoid field to zero from IP, the additional SC solenoids are designed inside ofthe QC2RE iron yoke on both beam lines.
3D magnetic field model is now under construction, again.
2012/02/20

SuperKEKB MAC 201224

EMF on Solenoids and Iron－2.86E4 N•

ESL and ESR: ON– Right side••••

3.70E4 N

Superconducting solenoid：3.70× 104 NIron in the front helium vessel：1.41 × 103 NIron in the rear helium vessel ：－9.86 × 103 N
Vacuum vessel (room temp.)：－2.86 × 104 N•

1.41E3 N－4.79E4 N
1.27E4 N– Left side•••－9.86E3 N－5E2 N

Superconducting solenoid ：－4.79 × 104 N
Iron in the front helium vessel ：8.08 × 103 N
Vacuum vessel (room temp.) ： 1.27 × 104 N

8.08E3 N－2.71E4 N

ESL and ESR: OFF– Right side•••

Iron in the front helium vessel ：－9.60 × 103 N
Iron in the rear helium vessel ：－1.67 × 104 N
Vacuum vessel (room temp.) ：－4.29 × 104 N－6.92 × 104 N– Left side••

2012/02/20

Iron in the front helium vessel ：8.47 × 104 N
Vacuum vessel (room temp.) ：1.42 × 104 N

SuperKEKB MAC 20129.89 × 104 N
25

R&D magnet status
Construction of QC1P R&D magnet
Construction of QC1RP R&D magnet started at the end of August inside thelaboratory of KEK and KEK personnel.
1st pole‐inner layer coil

New winding machine

1st pole‐outer layer coil

2012/02/20

SuperKEKB MAC 201226

R&D magnet status (cont.)
Construction of QC1P R&D magnet (cont.)
Collaringfour coils

Four coils completed at 3rd October.

b4 corrector

4 correctors were constructed in 2010.
The corrector package has a function ofmagnet bobbin for the QC1P R&Dmagnet.
2012/02/20

SuperKEKB MAC 201227

QC1P R&D magnet

QC1P

Four types of SC correctors

2012/02/20

SuperKEKB MAC 201228

Magnet R&D schedule• The QC1P R&D magnet has been tested at 4 K with the verticalcryostat in January.
– Excitation results:• QC1P R&D magnet: no quench up to the nominal current (1510A and G=75.58 T/m).
• Correctors (b1, a1, a2, b4), cancel coils (b1, b2, b3): no quench to the nominal current of 50 A.

– Field measurements:• There was some troubles in the harmonic coil.
• Now the coil is repaired, and the cold test is scheduled from the 22th February.

• The proto‐type of QC1E will be constructed in March and April
2012 and tested in May 2012.
• The proto‐type of QC1P will be constructed in August 2012 withthe company personnel after bidding the IR magnet‐cryostat
construction.

2012/02/20

SuperKEKB MAC 201229

Field measurement• Harmonic coil
– The harmonic coils were constructed and calibrated in‐house.
– Tangential coil + analog bucking(dipole and quadrupole coils) + digital bucking(two dipole and two quadrupole coils)– Integral coil (L=600 mm) + Mapping coil (L= 40 mm)• Design coil radius = 9.5 mm• Tangential winding coil = 100 turns

2012/02/20

SuperKEKB MAC 201230

Field measurement (cont.)• 7 coils in the harmonic coil were calibrated by standard dipole,quadrupole and sextupole– Parameters of the integral harmonic coil are listed.
Length(design),
mm

Radius(design),
mm

Radius(measured),mmPhase(design),
degreePhase(measured),degreeOpeningangle(design),
degreeOpeningangle(measured),degreeTangential
coil

585.59

9.5

9.587

0.0

0.0

18.69518.789D0 coil

596.5219.55559.577

0.0‐0.190180.0－

D1 coil

596.5219.5555

9.574

‐35.0

‐35.371

180.0－

D2 coil

596.5219.55559.604+35.0+34.688

180.0－

Q0coil596.5219.55559.574

0.0‐0.49690.0－

Q1coil596.5219.5555

9.576

‐25.0

‐25.53890.0－

Q2coil596.5219.55559.567+25.0+24.56290.0－Analog bucking ratio
D0=395, Q0=108：
Resolution of 10‐5 with respect to the quadrupole field of QC1P for measuring
the multipole field components
2012/02/20

SuperKEKB MAC 201231

Vibration study and measurement• In the last review meeting, we reported the cryostat design ofSuperKEKB and the vibration study for the cryostats.

SuperKEKB QCSLeftKEKB QCS
Right

Right

> 1Hz

> 10Hz> 1Hz> 10Hz> 1Hz> 10HzHori. Transverse, nm

87

80

107

100119112

Hori. axial, nm

37937840

11Vertical, nm

872890331511202012/02/20

SuperKEKB MAC 201232

Vibration study and measurement• In order to reduce amplitude of vibration, we plan to apply highvibration damping material to the support component.
– Material : MnCuNiFe Alloy.

• The vibration studies with the material have been performed for
the KEKB cryostat.
– The calculation is confirmed with the measurement on the KEKB cryostat.

Vibration amplitude= 44 % reduction

Welding the pieces of dumping material on
the surface of the support structure
2012/02/20

Vibration amplitude= 17 % reduction

Inserting the plates of dumping material between thesupport and stages. Bolts are dumping material.
SuperKEKB MAC 201233

Vibration study and measurement• The vibration studies with the dumping material will be
performed in March with the KEKB QCS cryostat in the right side.

2012/02/20

SuperKEKB MAC 201234

Construction schedule of IR magnets

2012/02/20

SuperKEKB MAC 201235

IR magnet‐cryogenic system commissioning
Cold BoxThe SC magnets
and cryogenic
system in the left
side will becommissioned at
first in May to
September 2014.

Cold Box

Cryogenictransfer line

Cryogenictransfer line
Cryostat‐L

Cryostat‐RBelle2012/02/20

SuperKEKB MAC 201236

Summary• Magnet and IR design– Basic magnet designs of SC‐QCs and SC‐correctors have been completed.
– Calculation of 3D Solenoid field is on going.
• Now improving the calculation model after one calculation for beam optics.

• SC correctors and leak field cancel coils– All correctors and leak field cancel coils will be manufactured by BNL
under the international research collaboration.
– The construction schedule by BNL completely matches with SuperKEKB IR
construction.

• R&D magnets– Construction of the QC1P R&D magnet was completed and cold tested.
– The magnetic field measurements of the magnet will be carried out from22th February.
– The constructions of QC1P and QC1E prototypes are scheduled in this year.

• Completion of the IR superconducting magnet construction isscheduled in the early of 2015.
2012/02/20

SuperKEKB MAC 201237