32 T All-Superconducting Magnet

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32 T All-Superconducting Magnet
W. Denis Markiewicz
User Committee Meeting National High Magnetic
Field Laboratory October 1-3, 2009
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Contents
Overview Magnet Parameters Schedule Installation T
echnology Development
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Overview
A proposal was submitted to the Major Research
Instrumentation program for a 32 T
all-superconducting magnet using YBCO coated
conductor inner coils. The proposal was funded
with an effective start date of Oct. 1, 2009, for
a duration of three years. The scope of supply
includes the full magnet system inner and outer
magnets, cryostat, power supply, and protection
electronics. The installation of the magnet is
presently planned for the milli-Kelvin facility.
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32 T Magnet Parameters
Total field 32 T Field inner YBCO coils 17
T Field outer LTS coils 15 T Cold inner bore 32
mm Uniformity 5x10-4 1cm
DSV Current 186 A Inductance 436 H Stored
Energy 7.54 MJ
YBCO
Nb3Sn
NbTi
YBCO coil 1 2 3 Inner radius (mm) 20 47 77 Outer
radius (mm) 42 71 101 Coil length
(mm) 144 240 340 Field increment
(T) 5.7 5.7 5.6 Conductor length (km) 0.75 2.4 5.2
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32 T Magnet System Components
System component Source YBCO coils NHMFL
YBCO conductor industry Outer magnet industry C
ryostat industry Power supply industry Protect
ion electronics NHMFL Facility NHMFL
Both the YBCO conductor and the outer magnet are
major components that will require collaboration
with industry to establish the design and
specification.
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32 T Project Schedule
We are here.
The funded project starts Q4 2009 and is planned
for three years. The program has three phases
(1) development, (2) prototype coils, and (3)
detailed design, fabrication and
procurement. Major procurements include the YBCO
conductor and the outer magnet.
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milli-Kelvin Facility
The low noise of the milli-Kelvin facility will
offer best advantage for the inherently quiet 32
T superconducting magnet. The long term goal is
the combine the 32 T magnet with a new dilution
refrigerator. Along with the other
superconducting magnets, the milli-Kelvin
facility has the infrastructure and staff to
support the 32 T magnet within the user facility.
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milli-Kelvin Facility
The 10 G and 100 G fringe field lines of the 32 T
magnet are shown for potential locations in the
milli-Kelvin facility.
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Technology Development Topics
Ic(B) critical current versus field Ic(?) critical
current versus field orientation Ic(e) critical
current versus strain s(e) stress strain
curve Es(e) secant modulus versus strain Joint
Ic(e) Joint resistance Joint strength Joint bend
characteristics Insulation conductor Pancake
winding Layer winding Quench protection
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YBCO Critical Current Characterization
Ic(B), Ic(?), Ic(e) Conductor is becoming well
characterized. Sufficient data for 32 T design.
Ic(?)
Ic(B perp)
Ic(e)
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YBCO Mechanical Characterization
s(e) stress-strain, Es(e) secant modulus The
conductor is mechanically well characterized for
the 32 T design.
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YBCO Joint Characterization
There are a large number of joints in the 32 T
YBCO coils. Measure joint mechanical strength is
high with no shear delamination. The literature
suggests high strain tolerance for soldered
joints. Initial in-house measurements show
relatively low values, but have been attributed
to unconstrained bending in the tensile
test. Further test method refinement and
additional tests are underway.
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Conductor Insulation
Insulation processes under examination Varnish
dip coat facility in place at NHMFL demonstrated
ability to coat with 25 µm build debonding
observed at high conductor strain examine thinner
builds, multiple pass Varnish spray
coat equipment being assembled objective thin
uniform coat with edge coverage Oxide coat ZnO,
Al2O3 Very thin coat potential lt 1µm
build Issues adherence, rate of deposition,
cost Working with industrial sources
YBCO conductor is not supplied with a thin
insulation suitable for high field magnet
construction.
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YBCO Coil Technology Development
Process Make a series of model and test
coils. Focus on the detailed, systematic
evaluation of components and processes. Establish
a reliable technology prior to fabrication of
major prototype coils. Options Pancake wound
coils. Positives ease of winding and
reinforcement, short conductor lengths. Negatives
large number of solder connections and
components, vulnerability of external
joints. Layer wound coils. Positives unified
winding pack, fewer connections Negatives wide
direction bend of conductor, joints within
windings.
Through a series of small coils, the technology
will be established before fabrication of major
prototype coils.
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YBCO Test Coils
SuperPower I. Bmax 26.8 T ?B 7.8 T
SuperPower II. Bmax 27 T ?B 7 T
NHMFL I. Bmax 33.8 T ?B 2.8 T
NHMFL II. Bmax 20.4 T ?B 0.4 T
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YBCO Test Coils and 32 T YBCO Coils
SuperPower I.
NHMFL I.
SuperPower II.
NHMFL II.
32 T YBCO Coils
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Quench Protection at Low Normal Zone Propagation
Velocity
Quench protection will be accomplished with
densely distributed heaters. Heater response time
and effective normal volume will be measured in
series of layer and pancake wound coils. Quench
protection study determines the required amount
of copper in the conductor.
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Project Staffing
Scott Bole (design) Andy Gavrilin (analysis) Ke
Han (materials) Jan Jaroszynski (conductor) David
Larbalestier (co-PI) Jun Lu (materials
characterization) Denis Markiewicz (PI) Lee Marks
(technician) Patrick Noyes (test)
Ken Pickard (technician) Andy Powell
(electronics) Bill Sheppard (technician) Kevin
Smith (administration) Ulf Trociewitz (magnet
design) Youri Viouchkov (design) Huub Weijers
(test) Vaughn Williams (machine shop) Aixia Xu
(conductor)
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The End Thank You