Super-KEKB QCS R&D Magnet
KEKNorihito Ohuchi
1.
2.
3.
4.
2007/3/20

Super-KEKB QCS Magnets
Cold Tests of QCS R&D Magnet
Construction of Corrector and Solenoid R&D Magnets
Summary and Schedule
KEKB Review 2007

1Super-KEKB QCS Magnets
Schematic view of SuperKEKB-IR

Parameters

2007/3/20

Super-KEKB

Present KEKB

Unit

Distance from IP to QCSL

0.969

1.6

m

Distance from IP to QCSR

1.163

1.92

m

Effective length of QCSL

0.357

0.483

m

Effective length of QCSR

0.299

0.385

m

Field gradient of QCSL

43.11

21.66

T/m

Field gradient of QCSR

43.11

21.73

T/m

KEKB Review 20072

Super-KEKB QCS Magnets
Cross Section of Magnet Cryostat and Parameters
Design parameters of final focus
quadrupole in the right side
(QCS-R:R&D Magnet)

Magnet cryostat cross sectionin the right side
2007/3/20••••

6 layer coils (3-double pane cake coils)
Inner coil radius : 90.0 mm
Outer coil radius : 116.8 mm
Cable size : 1.1 mm  4.1 mm•

Number of turns : 271 in one pole
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

 1.1 mm  7.0 mm (KEKB)KEKB Review 20073

Super-KEKB QCS Magnets
12 Cured Coils and Completed Collared Magnet

2007/3/20

KEKB Review 20074

Cold Tests of QCS R&D Magnet
Excitation Test at 4.2 K
Quench.his.070306.kdat

2000

Quench Current, A

1500

1801A

1437A
warming up
to room temp.

1000

500
Quench Cur, A (1st cooldown)
Quench Cur, A (2nd cooldown)

0051015202530

Quench #History of the quench training
The 1st quench training started at 1437 A.
2007/3/20

KEKB Review 20075

Cold Tests of QCS R&D Magnet
Load line of QCS R&D magnet
Quench.his.070306.kdat 20_54_04 2007_03_13

4.9T (Bmax)

Critical line at 4.2 K(actual cable performance)

8

Critical current on the load line
1879.4 A

Max. field in the magnet, T@I=1275A,r=94.2mm

2nd layer coil

1801 A
95.8 % of critical current

6

Critical line at 4.2 K(specification)
424.9T(Bmax )0050010001500

2000

2500

3000

QCS current, A

QCS load line vs. S.C. cable performance
1st layer coil
2007/3/20

KEKB Review 20076L1-14L

L1-12L

L1-11L

L1-10L

L1-9L

L1-8L

L1-7L

L1-6L

L1-5L

L1-12R

L1-11R

L1-10R

L1-9R-1

4Q-(5_6 layers)

4Q-(3_4 layers)

4Q-(1_2 layers)

3Q-(5_6 layers)

3Q-(3_4 layers)

3Q-(1_2 layers)

2Q-(5_6 layers)

2Q-(3_4 layers)

2Q-(1_2 layers)

1Q-(5_6 layers)

1Q-(3_4 layers)

1Q-(1_2 layers)#2-Quad(L2)#3-Quad(L2)#4-Quad(L2)#1-Quad(L2)

10.5
0-0.5

L2-14LL2-12LL2-11L

L2-10L

L2-9L

L2-8L

L2-7L

L2-6L

L2-5L

L2-12R

L2-11R

L2-10R

L2-9R

L2-8R

L2-7R

-1

L2-6R

2

QCS-R&D-L2coil.for.KEKB-MAC

1.5

L2-5R

4Construction Error of Coil End Position, mm# of quench-0.5

The 1st Layer-Coil-Position

600

L1-8R

80.5

L1-7R

# of quench#2-Quad(L1)#3-Quad(L1)#4-Quad(L1)#1-Quad(L1)

1

L1-6R

quench_pos&number 22:20:48 2007/03/14

10

QCS-R&D-L1coil.for.KEKB-MAC

1.5

L1-5R

Quench Location

Construction Error of Coil End Position, mm

Cold Tests of QCS R&D Magnet

The 2nd Layer Coil Position

Construction error of 1st and 2nd layer coils

1st layer coil

Coil #L1-10R

The location of the transition from the superconducting
to the normal condition is mainly in the 2 nd quadrant.

L1-6R
L1-5R

L1-8R

2007/3/20

KEKB Review 2007

L1-12R

L1-6L
L1-5L

L1-10L

L1-8L
L1-12L

7Cold Tests of QCS R&D Magnet
Quench Energy (Protection Circuit System)

Vtrigger=0.5 V
t=27 msec

QCS-training-#065
1002500

Quench02000-100

1500-200

1000

Current, A-300

500

Current, A

Total Coil Voltage (P1-P2), VP1-P2•••-366.39 V-400

00.5

1

1.5

2time, s•

QCS V-I curves after quench
2007/3/20

KEKB Review 2007

LQCSR=69.98 mH (calculation)
QQCSR=113.5 kJ at 1801A
Qdump=91.0 kJ (from V-I curves)
Qcoil=22.5 kJ
From the liquid helium consumption:
Evaporated LHe=13.96 L (measured)
QLHe=36.4 kJ
In the previous analysis, the temperaturerise of the magnet was less than 60 K forthe stored energy of 49 kJ at 1186.7 A.
8Cold Tests of QCS R&D Magnet
Field Measurement by harmonic coil (rough measurement)
QCS-mfm-#077

1@ magnet current = 1578A
The generated field gradient = 53.2 T/m
The magnetic length = 0.299 m (design)

H.C. signal, V

0.5@ design current (operation current) = 1186.7 A
The estimated field gradient = 40.03 T/m
The calculated field gradient = 40.12 T/m

0The error of the quadrupole component = 0.23%-0.5

The value of 0.23% corresponds to the geometryerror of 0.7mm in coil length, or 0.2 mm in coilradius.

-1
00.2

0.4

0.6

0.8

1time, sVoltage signal of the harmonic coil (one rotation) .
The harmonic coil is a quadrupole tangential winding.
The coil radius is 48 mm, and the length is 800 mm.
2007/3/20

KEKB Review 2007

9Construction of corrector and solenoid
R&D magnets
Magnetic field on SQR, Tesla

Design of the corrector R&D coils
The corrector system was reported at H.L. BFactory 2002.
1. The system consists of a skew quadruple
and two dipole coils as same as theKEKB-QCS.
2. The corrector coils are placed outside of
the stainless steel collars of QCS.
• Coil radius=141.5~146.5mm• Magnetic field from QCS andES=2.5T• Parameters of the skew quadrupole(SQR)
 Corrective angle 10mrad(0.83T/m)
 Coil radius=142.5mm
 Turns in one pole=122
 S.C. wire diameter=0.3mm
 Operation current=102A
2007/3/20

SQR-load-line.kdat

3.5

3Magnetic field in SQR withQCSR, ESR and Belle

2.5
4.2 K21.5
critical line at 4.7 K

10.5

0050

100

150200250

SQR current, AThe SQR current of 102 A corresponds to70 % of the critical current at 4.7 K.

KEKB Review 2007

10Construction of corrector and solenoid
R&D magnets
Construction of the corrector R&D coils
The corrector coils will be set on the outer surface of
the QCS helium vessel in the improved design inside
the cryostat.
1. The corrector coils are cooled by thermal
conduction via the helium vessel at 4.5 K.
2. The R&D coils are directly wound on thehelium vessel.
••••

The outer diameter of the helium vessel=216.3 mm (smaller than the originalcorrector design).
S.C. cable dia.=0.78mm
Turns of one pole=114
Dipole field=0.069 T @100A

Available correction of misalignment = 1.7mm

3. The HTS current leads will be used fortransporting the current to the coils.
•2007/3/20

The refrigerator will have the additionalcooling power of 15 W at 4.5K.

KEKB Review 2007

Automatic winding of the skew and thenormal dipole correctors by Toshiba. 11

Construction of corrector and solenoidR&D magnets
Construction of the solenoid R&D magnet
The compensation solenoids are designed tolocate in front of the QCS and on the peripheryof the QCS.
1. The solenoid R&D magnet are being
built by Toshiba in order to be
combined with the QCS R&D magnet.
2. Parameters of R&D solenoid (ESR-2).
•••

Coil length = 1000 mm.
Coil inner diameter = 330 mm
Turns of solenoid = 4000
500 turns ×8 layers••

Operation current = 619A
Designed central field = 2.98 T

3. Parameters of ESR-1•••

Coil length = 150 mmCoil inner diameter = 154 mm
Designed central field = 2.11 T

The solenoid R&D magnet is being constructedby Toshiba, and it will be completed in March.
2007/3/20

KEKB Review 2007

Solenoid winding @ Toshiba12Summary and Schedule• The QCS-R R&D was built and successfully tested at 4.2 K.
– The magnet quench started from the magnet current of 1437 A, which is higher than thedesign operating current.
– After 21 times of quenches, the magnet current reached 95% of the S.C. cable limitation.
– The quench location concentrated on the first built coils (2nd quadrant). It is considered thatthe cause came from the immature control of the coil size.
– The integral field gradient of the quadrupole was roughly measured, and the measured value
is 0.23 % different from the design.
– The precise field measurement will be performed with the harmonic coil system and thesignal integrators until this summer.

• The corrector and the compensation solenoid R&D magnets are being built
now, and they will be completed in March.
– The corrector R&D coils will be cooled by thermal conduction from the helium vessel, andfor transporting the current, the HTS current leads will be used in the system in order toreduce heat load. The system will be tested until this summer.
– The solenoid R&D magnet will be tested separately at first. After this test, the QCS R&D
magnet will be assembled in the solenoid bore, and the excitation test of both magnets will beperformed in this year.

2007/3/20

KEKB Review 200713

Corrector magnet test cryostat and solenoid R&D
magnet combined with QCS R&D magnet

2007/3/20

KEKB Review 200714