MUTAC Review, 9 April 2008 1 MuCOOL and MICE Coupling Magnet Status Michael A. Green Lawrence Berkeley Laboratory Berkeley CA 94720

MUTAC Review, 9 April 2008 1

MuCOOL and MICE Coupling Magnet Status

Michael A. Green

Lawrence Berkeley Laboratory

Berkeley CA 94720


The ICST Coupling Solenoid Design

Coupling Magnet Cryostat Coupling Magnet Cold Mass


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.


ICST Coil Winding Facility

De-spooling and Tensioning Apparatus Coil Winding Apparatus

Winding a Copper Test Coil


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.


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.


Coil Small Prototype Coupling96 layer24 layer 12 layer 96 layer 80 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

Parameters for the Test Coils and the Coupling Coil

The small test coil will have 24 layers. The large prototype test coil will have 96 layers.


Magnet Load Lines


Magnetic Field in the Small Test Coil at a Current of 512 A


After cooling to 4.2 K After charging to 512 A

Von Mises Stress of the Small Test Coil after Cool Down and Charging at 512 A


Magnetic Field in the Large Test Coil at a Current of 401 A


Von Mises Stress in the Large Test Coil

After Coil Winding After Coil Banding

After Cool Down to 4 K After Charge to 401 A


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.


Winding banding Cooling ChargingWinding coil

Von Mises Stress in the Coupling Coil

The stress and deflection calculations include the winding pre-stress in the coiland banding, which keeps the coil from lifting off the mandrel when it is fullycharged to a current of 210 A. The boundary conditions are different for thecoupling 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.


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.

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.

T = 0.074 K


Parameter 0 m 60 m

2-SectionHot Spot Temperature (K) 136 136

Max Internal Voltage (V) 6043 6006





Parameter 0 5



Results for Test Coil 2

Results for Coupling Coil

A Summary of Quench Protection Simulations for the 2nd Test Coil and the Coupling Coil


The ICST set up allows the coupling magnet to be trained rapidly to its full current.

Refrigerator

1500 mm ID Magnet Coil


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


• 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.

ICST MICE Magnet Milestones


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 doesn’t consider unforeseen problems that may be encountered when the MuCool magnet is run with the 1.5 W coolers for the first time.

Documents

MUTAC Review, 9 April 2008 1 MuCOOL and MICE Coupling Magnet Status Michael A. Green Lawrence Berkeley Laboratory Berkeley CA 94720