1. BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu
Concept Design of BESIII Superconducting Magnet
Zian Zhu
Basic parameters
Coil design
Magnetic field analysis
Cryostat design
Coil support structure
Cryogenics
Yoke configuration
Cost and milestone
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

2. BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu
Concept Design of BESIII Superconducting Magnet
Basic Parameters
Physics requirement
Central field B = 1.0 T
Dimension of magnet(RT volume): L = 3.9 m, D = 2.65 m
Uniformity B/B < 5% in the tracking volume
Cool-down time t < 10 days
Configuration
Single layer solenoid coil, steady field
In-direct cooling by two phase flow liquid helium
Pure aluminum based stabilizer
NbTi/Cu superconductor
Ramp rate: reached to operating current in 0.5hours
Recovery time: <1 day
Field stability: 5×10-4
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

3. BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu
Concept Design of BESIII Superconducting Magnet
Basic Parameters
Cryostat
Inner radius
1.325m
Outer radius
1.7m
Length
3.9m
Coil
Effective radius
1.45m
3.5m
Cable dimension
3.7mm*20mm
Electrical parameters
Central field
1.0T
Nominal current
3000A
Inductance
2.0H
Stored energy
9.2MJ
Cold mass
3.5ton
Total Weight
14.6ton
Radiation thickness
1.86X0
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

4. BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu
Concept Design of BESIII Superconducting Magnet
Coil Design
3.2mm2
,I=3000A
921 turns for a 3.5m long coil
,w=3.7mm
= 9.2MJ
= 2H
Cross section of the superconducting cable
70K
4N Purity
aluminum-stabi1izer
RRR=~300
20mm
Working
NbTi NbTi/Cu ratio 1.09:1
Cross Section Area of NbTi/Cu: 3.2mm2
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

5. Coil Design Concept Design of BESIII Superconducting Magnet
Stress in the Coil
Radial Magnetic Pressure
Hoop stress
t is thickness of coil plus support cylinder
When thickness of support cylinder is15mm, t=35mm
Maximum hoop stress is 19 Mpa
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

6. BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu
Concept Design of BESIII Superconducting Magnet
Coil Design
Other analysis
Estimation of coil Ohmic heats by th joints: mW
Voltage versus length of quench area in the coil
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

7. BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu
Concept Design of BESIII Superconducting Magnet
Coil Design
Coil Cross Section
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

8. Magnetic field analysis
Concept Design of BESIII Superconducting Magnet
Magnetic field analysis
Flux line
Contour plot
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

9. Magnetic field analysis
Concept Design of BESIII Superconducting Magnet
Magnetic field analysis
field uniformity
inside the Drift chamber
B along beam axis
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

10. Magnetic field analysis
Concept Design of BESIII Superconducting Magnet
Magnetic field analysis
End Yoke L1~L9 30,30,30,30,30,40, 80, 80, 300mm
Barrel Yoke L1~L9 20,20,20,40,40,80,80,100, 400mm
End Yoke L1~L9 30,30,30,30,30,40,80,80,80mm
Barrel Yoke L1~L9 30,30,30,40,40,80,80,80,80mm
When anti-solenoid excited
End Yoke L1~L9 30,30,30,30,30,40,80, 80,300mm
Barrel Yoke L1~L9 30,30,30,40,40,80,80,80,400mm
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

11. BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu
Concept Design of BESIII Superconducting Magnet
Cryostat Design
Outer cylinder,Inner cylinder,End plates
Material: SUS316L
Buckling check
Mechanical strength check
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

12. BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu
Concept Design of BESIII Superconducting Magnet
Cryostat Design
Thickness:
Outer vessel =16 mm
Inner vessel = 5 mm
End vessel = 32 mm
Max. Stress: MPa
Max. Deformation: 0.18mm
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

13. Coil Support Structure
Concept Design of BESIII Superconducting Magnet
Coil Support Structure
Rods material: GFRP
12 axial support rods
at chimney side
12 radial support rods
6 at each end
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

14. Coil Support Structure
Concept Design of BESIII Superconducting Magnet
Coil Support Structure
Axial decentering force
N/5cm
Radial decentering force
34695 N/5cm
Diameter of the rods for the nitrogen shield is 15mm,
6mm for radial and axial support.
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

15. Weight and Radiation thickness
Concept Design of BESIII Superconducting Magnet
Weight and Radiation thickness
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

16. BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu
Concept Design of BESIII Superconducting Magnet
Cryogenics
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

17. BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu
Concept Design of BESIII Superconducting Magnet
Cryogenics
Cooling Type Normal: Forced 2-Phase Helium Cooling
Trouble: Thermo-syphon Cooling
Volume of Working Fluid Coil: 50 L
Service Port: 200 L
Shield: 16 L
Coil Pipe Outer Diameter: 31 mm
Inner Diameter: 25 mm
Total Length: 102 m
Number of Line: One
Shield Pipe Outer Diameter: 18 mm
Inner Diameter: 14 mm
Total Length: 70 m
Number of Line: Two (One for each side)
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

18. BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu
Concept Design of BESIII Superconducting Magnet
Cryogenics
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

19. BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu
Concept Design of BESIII Superconducting Magnet
Yoke Configuration
End Yoke L1~L9
30,30,30,30,30,40,80, 80,300mm
Barrel Yoke L1~L9
30,30,30,40,40,80,80,80,400mm
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

20. BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu
Concept Design of BESIII Superconducting Magnet
Magnet
support structure
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

21. BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu
Concept Design of BESIII Superconducting Magnet
Cost Estimation
Item
Cost(Million RMB,exclude Tax)
Superconducting Cable
9.8
Magnet Fabrication
31.0
Field Mapping
0.9
Vacuum Device
0.4
Control System
0.6
Power Supply/Quench Device
2.4
Sporadic Machining
0.2
Business trip
0.3
Total
45.6
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

22. BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu
Concept Design of BESIII Superconducting Magnet
Milestone
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu

23. BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu
Concept Design of BESIII Superconducting Magnet
Acknowledgement
KEK experts group:
Prof. H.Tsuchiya, Y.Makida, H.Yamaoka.
Design group members:
S. Han, L.Liu
Leaders:
S. Kurokawa, Weiguo Li
BESIII Collaboration Meeting, June 5~6, 2002, Zian Zhu