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Progress on the MICE Cooling Channel Solenoid Magnet System

 M.A. Green, S. Q. Yang, G. Barr, U. Bravar, J. Cobb   W. W. Lau, R.S. Senenayake, 

H. Witte, A. E. White Physics Department, Oxford University, UK

D. Li and S. P. VorostekLawrence Berkeley Laboratory, Berkeley USA

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• Introduction of MICE Cooling Channel• MICE Absorber Focusing Coil module• The Focusing Magnet Design• FEA Models of the Focusing magnet • MICE RF and Coupling Coil module• The Coupling Magnet design• FEA Models of the Coupling Magnet• Tasks Completed and Tasks to Do • Conclusion

Outline

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Focusing and Coupling Magnet ReportsM. A. Green and S. Q. Yang, “Heat Transfer into and within the 4.4 K Region and the 40 K Shields of the MICE Focusing and Coupling Magnets” Oxford University Physics Report, 28 April 2004

M. A. Green and R. S. Senanayake, “The Cold Mass Support System for the MICE Focusing and Coupling Magnets,” Oxford University Physics Report, 23 August 2004

M. A. Green and S. Q. Yang, “The Coil and Support Structure Stress and Strain the MICE Focusing and Coupling Magnets,” Oxford University Physics Report, 30 August 2004

M. A. Green, “Cooling the MICE Magnets using Small Cryogenic Coolers,” Oxford University Physics Report, 10 September 2004

S. Q Yang, M. A. Green, G. Barr, et al, “The Mechanical and Thermal Design for the MICE Focusing Solenoid Magnet System,” submitted to IEEE Transactions on Applied Superconductivity 15, (2005), submitted 5 Oct. 05

M. A. Green, S. Q. Yang, U. Bravar, et al, ““The Mechanical and Thermal Design for the MICE Coupling Solenoid Magnet,” submitted to IEEE Transactions on Applied Superconductivity 15 (2005), submitted 5 Oct. 05

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The MICE Cooling Channel

AFC Module

RF Cavity

Focusing Coil

Coupling Magnet Cryostat

Coupling Coil

Focusing Magnet Cryostat

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Half Section View of the MICECooling Channel

AFC Module

RF CavitiesAbsorber

Focusing Coil

Coupling Coil

Coupling Magnet CryostatRF Coupling Module

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MICE Focusing Magnet

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MICE: Absorber Focusing Coil (AFC) module

AFC 3D View

S/C Coil 2

Safety Window

Absorber Body

Coil Mandrel

Magnet Vacuum

Absorber Vacuum Door

Hydrogen duct

S/C Coil 1

LH2 window

Absorber vacuum

Module vacuum vessel

Cooler

AFC 2D Cross-section

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210 mm

84 mm

670 mm725 mm

235 mm

249 mm

263 mm

~450 mm

Machined 6061-T6Aluminum Forging6061 Al Cover Plate 13 mm

6.4 mm 304 St St Vessel

1 mm Cu Shield

10 mm ID He Tube

5 mm 304 St St 1 mm G-10 Insulation

~697 mm

844 mm

200 mm

12.7 mm 304 St St Module Vessel

MICE Focusing Solenoid Cross-section

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AFC Magnet Cross-section

Focusing Magnet

Cold Mass SupportMagnet Coil and Absorber Cross-section

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The Basic Parameters of the Focusing Magnet in the Non-flip and the Flip Mode

Parameter Non-flip Flip

Coil Separation (mm) 200 200

Coil Length (mm) 210 210

Coil Inner Radius (mm) 263 263

Coil Thickness (mm) 84 84

Number of Layers 76 76

No. Turns per Layer 127 127

Magnet J (A mm-2)* 71.96 138.2

Magnet Current (A)* 130.5 250.7

Magnet Self Inductance (H) 137.4 98.6

Peak Induction in Coil (T)* 5.04 7.67

Magnet Stored Energy (MJ)* 1.17 3.10

4.2 K Temp. Margin (K)* ~2.0 ~0.5

Inter-coil Z Force (MN)* -0.56 3.40

* Design based on p = 240 MeV/c and beta = 420 mm.

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10864200

100

200

300

400

T = 3.4 K

T = 4.2 K

T = 5.0 K

Focusing flip

Focusing no-flip

Induction at the Conductor (T)

Conductor Current (A)

The Focusing Magnet Load Lines and Conductor Current Versus the Magnetic Induction at Various Conductor T

TM = 2.0 K

TM = 0.5 K

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Local region applied 4.3K

T = 1.08 K

The focus magnet is attached to the cooler along a 100 mm wide strip that is at 4.3 K.

The radiation heat load on all other surfaces QR = 1.0 W m-2.

The maximum T = 1.08 K

T1T0Cooler 2nd Stage Cold HeadFlexible Copper StrapT3Vacuum VesselFocusing MagnetT2

Focusing Magnet T, Cooling along One Line

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Focusing Magnet T, Outside Cooling

The heat flux on the inner cylindrical surface and the ends is 1 W m-2; the outer cylindrical surface is at 4.3 K.

The maximumT = 0.125 K

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Magnet connection to the Cooler with a Liquid Helium Cold Pipe

PT3T2T1T0Cooler 2nd Stage Cold HeadCondensation PlateVacuum VesselLiquid Tube (any length)Gas Tube (any length)Liquid HeliumFocusing MagnetRelief ValveCryostat Neck

The superconducting coils for the MICE focus magnets will be cooled by conduction from liquid helium in a space on the outside of the magnet coils. A simple gravity feed heat pipe supplies cold liquid from the helium condenser to the bottom of the magnet. The boil off gas is re-liquefied on a condenser surface and the condense liquid helium is sent back to the bottom of the magnet helium tank

T2 - T1 < 0.1

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Focusing magnet Stress and Deflection due to the Cool Down

The results show the Von Mises Stress, Radial Deflection (negative y direction) and Longitudinal Deflection (z direction) due to cooling the Focusing Magnet Module from Room Temperature to 4.2 K.

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Focusing magnet Stress and Deflection due to the Cool Down and Magnetic Forces

The results show the von mises stress, the radial (the Y direction) and longitudinal (the Z direction) deflections, for the focusing magnet module that has been cooled from room temperature to 4.2 K, and the coils are powered for as in the baseline full-flip case with a muon beam with an average momentum of 240 MeV/c.

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MICE Coupling Magnet

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MICE: RF and Coupling module

Three quarter section 3D View of RF module

Coupling Magnet

Cavity RF Coupler

Dished Be Window

RF Cavity Cell

Module Vacuum Vessel

Vacuum Pump

Magnet Vacuum Vessel

2D view of the RF and Coupling Module

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MICE Coupling Solenoid Cross-section

30 to 40 K Shield

Cooling Tube

S/C Coil

~697 mm

Cryostat Vacuum Vessel

>1080 mm

725 mm

250 mm

386 mm

201 MHz RF Cavity

Vacuum Space

116 mm

Helium Space

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Relationship of the Coupling Coil to the Cavity

Coupling Coil

Cavity Coupler

Vacuum Pump201 MHz RF Cavity

Be Window

The coupling coil length is determined by the position of the RF couplers.

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The Basic Parameters of the Coupling Magnet in the Non-flip and the Flip Mode

Parameter Non-flip Flip

Coil Length (mm) 250 250

Coil Inner Radius (mm) 725 725

Coil Thickness (mm) 116 116

Number of Layers 104 104

No. Turns per Layer 151 151

Magnet J (A mm-2)* 104.9 115.5

Magnet Current (A)* 193.6 213.2

Magnet Self Inductance (H) 563 563

Peak Induction in Coil (T)* 7.09 7.81

Magnet Stored Energy (MJ)* 10.6 12.8

4.2 K Temp. Margin (K)* ~0.9 ~0.6

* Design based on p = 240 MeV/c and beta = 420 mm.

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The Coupling Magnet Load Lines and Conductor Current Versus the Magnetic Induction at Various Conductor T

1098765432100

100

200

300

400T = 3.4 KT = 4.2 KT = 5.0 KCoupling flipCoupling no-flip

Magnetic Induction in the Conductor (T)

Current in the Conductor (A)

TM = 0.6 K

TM = 0.9 K

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Temperature Distribution on the Coupling Coil as a Function of Cooling Location

T = 4.085 K

4.3 K

QR = 1.0 W m-2

a) Cooling at one point onthe outside surface 4.3 K

QR = 1.0 W m-2

4.568 K

T = 0.268 K

b) Cooling on the entire outside surface

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Cooler Circuit for the Coupling Magnet

The heat pipe reducesT2-T1 to < 0.1 K.

See page 23 for reductionT3-T2 within the coil.T3-T0 is ~ 0.2 K

There is no copper strapbetween the cooler and the magnet.

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Coupling Magnet Stress and Deflection due to the Cool Down and Magnetic Forces

The results show the von Mises stress, the radial (the Y direction) deflection, for the coupling magnet cooled from 300 K to 4.2 K, and the coils are powered for the full-flip case with a muon beam with a momentum of 200 MeV/c.

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Tasks Completed and Tasks to Do

Focusing Coupling

Basic Coil Design based on a Conductor Yes Yes

Temperature Distribution in Magnet Yes Yes

Stress and Deflection in Magnet Yes Yes

Cold Mass Support System Design Yes Yes

Cooler Selection and Hook Up Design Yes Yes

Quench Protection System Design Yes Dec 2004

Engineering Completed for a RFP* April 2005 June 2005

Specifications for the RFP* April 2005 June 2005

Safety Documentation for RFP* Sept. 2005 Sept. 2005

Power Supply Specification* Sept. 2005 Sept. 2005

* Based on developing a performance specification (not build to print)

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Other Magnet Related Tasks to Do

• Complete and check the cold mass support force calculations for all relevant cases. Partly Done

• Check the worst cases forces to be encountered during a magnet quench. Partly Done

• Determine if a quench of one magnet in MICE can will cause other magnets to quench inductively.

• Design the copper current leads from 300 K to 50 K for currents of 300 A and 60 A. Partly Done

• Select the 300 A and 50 A HTS leads. Partly Done

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Conclusions

• Most of the relevant design calculations have been done for the focusing and coupling magnets.

• Most of the relevant calculations have been done to allow the magnets to be cooled by small coolers.

• The 2D and 3D Drawings of the entire channel are beginning to come together.

• More work must be done a quench calculations.

• The RFP specifications for the magnets and magnet subcomponents need to be written.

• The magnets must be looked at for safety hazards.