MuCOOL and MICE Coupling Magnet Status

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MuCOOL and MICE Coupling Magnet Status

• Michael A. Green
• Lawrence Berkeley Laboratory
• Berkeley CA 94720

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The ICST Coupling Solenoid Design
Coupling Magnet Cryostat
Coupling Magnet Cold Mass
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Magnet Progress to Date

• A portion of the superconductor has been
  delivered. The rest of the conductor is being
  fabricated.
• Engineering design of the coupling magnet is over
  90 percent complete.
• The engineering design of the two ICST test coils
  is complete.
• The coil winding tooling is complete.
• The first dummy test coil is being wound at ICST.
• The first test coil joints have been fabricated.
  The joints will be tested in a magnetic field at
  Berkeley.

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ICST Coil Winding Facility
Coil Winding Apparatus
De-spooling and Tensioning Apparatus
Winding a Copper Test Coil
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Purpose of Test Coil 1

• This coil is the first superconducting solenoid
  wound with the coupling coil conductor.
• The joint design and the coil taps for the quench
  protection system is verified in this magnet.
• This coil will be part of the crew training
  process.
• Test coil 1 will produce enough field so that the
  magnet can be used for cold diode tests and other
  sorts of tests to be done in a magnetic field at
  300 K, 77 K and 4.2 K.
• Both of the superconducting test coils will be
  cooled using the ICST refrigerator.

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Purpose of Test Coil 2

• The winding parameters for the coupling coil will
  established by winding a full diameter test coil.
• The 2nd test coil will be cooled down using the
  ICST refrigerator in a cryostat suitable for the
  training the large test coil and the coupling
  magnets.
• Test coil 2 will be strained by the cool down and
  the magnetic field so that the worst case strain
  seen by the MICE coupling coils is seen in the
  test coil.
• There will be a full scale test of the coupling
  coil cold diode and resistor quench protection
  system with the test coil sub-divided into four
  circuits.

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Parameters for the Test Coils and the Coupling
Coil
Coil Small Small Prototype Prototype Coupling 96 layer
Coil 24 layer 12 layer 96 layer 80 layer Coupling 96 layer
Coil Length (mm) 285 285 72 72 285
Coil Inner Radius (mm) 175 175 750 750 750
Coil Thickness (mm) 25.5 12.8 102.5 85.4 102.5
Number of Layers 24 12 96 80 96
No. Turns per Layer 166 166 42 42 166
Magnet J (A mm-2) 114.6 114.6 114.6 114.6 114.6
Magnet Current (A) 210 210 210 210 210
Self Inductance (H) 4.529 1.11 50.059 35.88 592.5
Peak Induction in Coil (T) 2.79 1.43 3.91 3.56 7.44
Magnet Stored Energy (KJ) 99.867 24.4 1104 791.2 13069
4.2 K Temp. Margin (K) 3.3 3.9 2.5 2.9 0.8
Conductor Len/coil (km) 4.701 2.27 20.299 16.735 80.118
The small test coil will have 24 layers. The
large prototype test coil will have 96 layers.
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Magnet Load Lines
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Magnetic Field in the Small Test Coil at a
Current of 512 A
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Von Mises Stress of the Small Test Coil after
Cool Down and Charging at 512 A
After cooling to 4.2 K
After charging to 512 A
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Magnetic Field in the Large Test Coil at a
Current of 401 A
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Von Mises Stress in the Large Test Coil
After Coil Banding
After Coil Winding
After Charge to 401 A
After Cool Down to 4 K
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Stress and Deflection Simulations for the 2nd
Test Coil (the full diameter test coil)

• Stress and deflection simulations were done on
  the large test coil. Stress and deflection
  calculations were done after the magnet was
  cooled to 4.2 K and powered to 401 A.
• The hoop stress and Von Mises stress is almost
  the same for the large test coil at 401 A when
  compared to the coupling coil at 210 A. The
  radial deflection is also similar. If the large
  test coil can operate at 400 A, the coupling coil
  should operate to at least 200 A.

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Von Mises Stress in the Coupling Coil
Winding banding
Charging
Winding coil
Cooling
The stress and deflection calculations include
the winding pre-stress in the coil and banding,
which keeps the coil from lifting off the mandrel
when it is fully charged to a current of 210 A.
The boundary conditions are different for
the coupling coil than they were for the large
test coil. The minimum winding Pre-stress is 70
MPa. The aluminum banding pre-stress is 30 MPa.
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Modeling the Temperature Distribution in the
Coupling Coil during Normal Operation
The heat flow into the magnet as shown is 1.5 W
from radiation and conduction.
DT 0.074 K
The heat flow due to AC losses in the magnet coil
during to a rapid discharge from 210 A to no
current in 5400 seconds has also been modeled
using ANSYS. The coupling magnet can be
discharged in 5400 seconds without quenching.
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A Summary of Quench Protection Simulations for
the 2nd Test Coil and the Coupling Coil
Results for Test Coil 2
Parameter Parameter 0 mW 60 mW
2-Section Hot Spot Temperature (K) 136 136
2-Section Max Internal Voltage (V) 6043 6006
4-Section Hot Spot Temperature (K) 129 129
4-Section Max Internal Voltage (V) 3112 3074
6-Section Hot Spot Temperature (K) 127 126
6-Section Max Internal Voltage (V) 2077 2043
Results for Coupling Coil
Parameter Parameter 0 W 5 W
8-Section Hot Spot Temperature (K) 135 88
8-Section Max Internal Voltage (V) 2669 1391
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The ICST set up allows the coupling magnet to be
trained rapidly to its full current.
Refrigerator
1500 mm ID Magnet Coil
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ICST MuCOOL Milestones

• Complete the large coil test stand 6/15/08.
• Complete the two test coils 6/30/08.
• Finish winding the MuCool Coil 7/31/08.
• Complete the MuCool coil Cold Mass 9/20/08.
• Train MuCool coil cold mass assembly 9/30/08.
• Finish Mucool magnet assembly 12/02/08.
• Mucool magnet acceptance test finished 1/01/09.
• Ship Mucool magnet to Fermilab 1/10/09

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ICST MICE Magnet Milestones

• Finish winding 1st MICE coil 10/09/08.
• Finish and train 1st MICE coil assembly 11/30/08.
• Finish winding 2nd MICE coil 12/18/08.
• Finish 1st MICE magnet assembly 2/09/09.
• Finish and train 2nd MICE coil assembly 2/17/09.
• 1st MICE magnet acceptance test finished 3/02/09.
• Ship 1st MICE magnet to LBNL 3/15/09.
• Finish 2nd MICE magnet assembly 4/28/09.
• 2nd MICE magnet acceptance test finished 5/29/09
• Ship 2nd MICE magnet to LBNL 6/10/09.

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Concluding Comments

• The coupling magnet engineering is nearly done,
  but there may be a few changes in the final
  design based on what is learned from the two test
  coils.
• The schedule for the Mucool and MICE magnets is
  based on things going well. The schedule doesnt
  consider unforeseen problems that may be
  encountered when the MuCool magnet is run with
  the 1.5 W coolers for the first time.