Download Super-conducting magnet

Superconducting Solenoid Magnet
Zian Zhu
BESIII Workshop
Zian Zhu
Beijing, Oct.13,2001
Superconducting Solenoid Magnet
BESIII Workshop
Zian Zhu
Beijing, Oct.13,2001
Superconducting Solenoid Magnet
• The solenoid magnet provides an axial magnetic field of
about 1.2 Tesla over the tracking volume of BESIII,field
uniformaty <5%.
• The magnetic field produced by the coil is returned by
the steel plates of the surrounding Muon detector. (~12
layers in barrel,space for endcap,proper aperture of end
yoke for SC quadruple)
• Compositive field with SC quadruple
BESIII Workshop
Zian Zhu
Beijing, Oct.13,2001
Superconducting Solenoid Magnet
Detector Magnet System
Cryostat
Cryogenics Chimney
Coil
Power Supply
Quench Protection
Control
Dewar
BESIII Workshop
Yoke
(Barrel/End)
Zian Zhu
Field Mapping
Beijing, Oct.13,2001
Superconducting Solenoid Magnet
Magnet Characteristics
Cryostat Inner Radius
1.0 m
Outer Radius
1.3 m
Total Length
3.4 m
Nominal Magnetic Field 1.2 T
Cool Down Time
< 7 days
Quench Recovery Time
< 1 day
BESIII Workshop
Zian Zhu
Beijing, Oct.13,2001
Superconducting Solenoid Magnet
Magnetic Field Design
The field
uniformity and
forces on the coil
are strongly
influenced by the
proximity of the
iron yoke.
We will calculate
the field and
forces using the
ANSYS program.
BESIII Workshop
B along Z axis (B0=1T, Poisson method)
Zian Zhu
Beijing, Oct.13,2001
Superconducting Solenoid Magnet
Flux line display
(Poisson method)
BESIII Workshop
Zian Zhu
Beijing, Oct.13,2001
Superconducting Solenoid Magnet
Coil Design
Super Conductor
Support cylinder
Cooling Tube
Cryostat
Chimney
BESIII Workshop
Zian Zhu
Beijing, Oct.13,2001
Superconducting Solenoid Magnet
Parameters of the Solenoid Coil
Cryostat Inner Radius
1.0 m
Outer Radius
1.3 m
Length
3.4 m
Coil Effective Radius
1.15 m
Length
3.0 m
Conductor Dimension
3 x 33 mm2
Outer cylinder Thickness
15 mm
Center Field
1.2 T
Nominal Current
3000 A
Inductance
6.12 H
Stored energy
9 MJ
Stored energy/cold mass(E/M)
6 kJ/kg
Charging time
0.5 hour
Effective cold mass
4.3 tons
BESIII Workshop
Zian Zhu
Beijing, Oct.13,2001
Superconducting Solenoid Magnet
* We can benefit from other successfully solenoid
magnets, particular the BELLE coil.
* The primary issue regarding conductor fabrication is
the cross sectional aspect ratio of the conductor.
Co-extruded cable: the superconducting cable is at the
center of the aluminum stabilizer. We will compare in
several conductor options. Here is a conductor BELLE
using: 3x33 mm2.
* Stability against a quench: Even if the total
magnetic energy were dumped entirely into the
conductor, the material of the 33 mm thick coil should
be sufficient to keep the coil temperature below 80 K
after a quench at the operating current.
* The coil consists of a single layer aluminum
stabilized superconductor coil wound around and glued
on the inner surface of an aluminum support cylinder.
Superconductor
Cross section
BESIII Workshop
* The electric ground insulation between the coil and
the support cylinder must have breakdown voltage
larger than 2kV.
Zian Zhu
Beijing, Oct.13,2001
Superconducting Solenoid Magnet
Coil
Cross
View
BESIII Workshop
Zian Zhu
Beijing, Oct.13,2001
Superconducting Solenoid Magnet
Cryostat
Radiation shield
Vacuum vessel
inner/outer vessel
connected by flat annular
bulkheads at each end,
made by non magnetic
metal
Cooling:
2 phase force flow
Lhe circulating through the
tube welded on the outer
surface of the support
cylinder.
2mm thick pure aluminum strips
are wound on the inner surface of
the coil to increase the
propagation velocity of the quench
BESIII Workshop
Zian Zhu
Beijing, Oct.13,2001
Superconducting Solenoid Magnet
Coil Support
Sketch map,
Detail study is under
investigation
BESIII Workshop
Zian Zhu
Beijing, Oct.13,2001
Superconducting Solenoid Magnet
Chimney
The cryogenic lines and the superconducting leads from the coil go through the chimney
to the outside of the iron structure. The lines and leads are surrounded by multi layer
thermal shields and the vacuum jacket.
The chimney protrudes vertically up ward from one end of the coil. The annular space
between the thermal shield and the vacuum jacket is occupied by the flow channels for
the pressure relief and vacuum exhaust lines. Pressure relief is needed to protect the
vacuum vessel from overpressure in the event of an accidental leak of cryogens from the
cooling line. The relief device and vacuum pump are located on the top of the detector.
A hole of dimension 50x50 cm2 in the iron yoke accommodates the chimney.
BESIII Workshop
Zian Zhu
Beijing, Oct.13,2001
Superconducting Solenoid Magnet
Cryogenics
•Common cryogenics with mini beta
magnet
•150W+80W
BESIII Workshop
Zian Zhu
Beijing, Oct.13,2001
Superconducting Solenoid Magnet
Power Supply
•3000 A and 10 V
•Dump resistor needed
•Protection circuit
•Three modes of switching and discharging for the extraction of the electromagnetic
stored energy from the magnet.
Fast discharge system: quickly switch off the circuit and extract the energy to
the dump resistor. This mechanism must work during power failures.
Quench protection: It is required to have sufficient redundancy in the fast
discharge system and quench detectors for safe quench protection.
Slow discharge system: discharge the coil sufficiently slowly so that the eddy
current in the coil will not initiate a quench.
BESIII Workshop
Zian Zhu
Beijing, Oct.13,2001
Superconducting Solenoid Magnet
Mechanical Design
Force Calculations
•The radial magnetic pressure
•The Hoop stress
• The compressive force
•The axial stress
•The combined stress
BESIII Workshop
Zian Zhu
Beijing, Oct.13,2001
Superconducting Solenoid Magnet
Schedule
2001.10~2002.09: Concept design/Engineering design
2002.07:
order conductor
2002.10~2005.02: Coil fabrication, test
cryogenics,mapping machine,power supply
2005.03:
shipping
(2004.06~2004.09): Disa. BESII
(2004.10~2005.03):Assembly iron yoke,cryogenics commission
(2005.04~2005.06):SC solenoid and quadruple magnet commission
(2005.07~2005.08):Field mapping
BESIII Workshop
Zian Zhu
Beijing, Oct.13,2001
Superconducting Solenoid Magnet
Need Support
from Domestic and Overseas
Concept design
Coil/Cryostat fabricate
Chimney
Power
Cryogenics
Filed mapping
BESIII Workshop
Zian Zhu
Beijing, Oct.13,2001