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. Vorostek Lawrence Berkeley Laboratory, Berkeley USA

Outline 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

Focusing and Coupling Magnet Reports M. 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

The MICE Cooling Channel Coupling Coil Focusing Coil RF Cavity Coupling Magnet Cryostat Focusing Magnet Cryostat AFC Module

Half Section View of the MICE Cooling Channel Coupling Coil RF Cavities Absorber AFC Module RF Coupling Module Coupling Magnet Cryostat Focusing Coil

MICE Focusing Magnet

MICE: Absorber Focusing Coil (AFC) module Cooler Magnet Vacuum Absorber Vacuum Door Coil Mandrel Hydrogen duct Absorber Body Safety Window S/C Coil 1 LH2 window S/C Coil 2 Absorber vacuum Module vacuum vessel AFC 2D Cross-section AFC 3D View

MICE Focusing Solenoid Cross-section

AFC Magnet Cross-section Focusing Magnet Cold Mass Support Magnet Coil and Absorber Cross-section

The Basic Parameters of the Focusing Magnet in the Non-flip and the Flip Mode Coil Separation (mm) 200 Coil Length (mm) 210 Coil Inner Radius (mm) 263 Coil Thickness (mm) 84 Number of Layers 76 No. Turns per Layer 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.

The Focusing Magnet Load Lines and Conductor Current Versus the Magnetic Induction at Various Conductor T TM = 0.5 K TM = 2.0 K

Focusing Magnet DT, Cooling along One Line Local region applied 4.3K DT = 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 DT = 1.08 K

Focusing Magnet DT, 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 maximum DT = 0.125 K

Magnet connection to the Cooler with a Liquid Helium Cold Pipe T2 - T1 < 0.1 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

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.

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.

MICE Coupling Magnet

MICE: RF and Coupling 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 Three quarter section 3D View of RF module

MICE Coupling Solenoid Cross-section

Relationship of the Coupling Coil to the Cavity Be Window Cavity Coupler 201 MHz RF Cavity Vacuum Pump The coupling coil length is determined by the position of the RF couplers.

The Basic Parameters of the Coupling Magnet in the Non-flip and the Flip Mode Coil Length (mm) 250 Coil Inner Radius (mm) 725 Coil Thickness (mm) 116 Number of Layers 104 No. Turns per Layer 151 Magnet J (A mm-2)* 104.9 115.5 Magnet Current (A)* 193.6 213.2 Magnet Self Inductance (H) 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.

The Coupling Magnet Load Lines and Conductor Current Versus the Magnetic Induction at Various Conductor T TM = 0.6 K TM = 0.9 K

entire outside surface a) Cooling at one point on Temperature Distribution on the Coupling Coil as a Function of Cooling Location Cooling on the entire outside surface QR = 1.0 W m-2 4.3 K 4.568 K DT = 4.085 K a) Cooling at one point on the outside surface QR = 1.0 W m-2 4.3 K DT = 0.268 K

Cooler Circuit for the Coupling Magnet The heat pipe reduces T2-T1 to < 0.1 K. See page 23 for reduction T3-T2 within the coil. T3-T0 is ~ 0.2 K There is no copper strap between the cooler and the magnet.

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.

Tasks Completed and Tasks to Do Focusing Coupling Basic Coil Design based on a Conductor Yes Temperature Distribution in Magnet Stress and Deflection in Magnet Cold Mass Support System Design Cooler Selection and Hook Up Design Quench Protection System Design Dec 2004 Engineering Completed for a RFP* April 2005 June 2005 Specifications for the RFP* Safety Documentation for RFP* Sept. 2005 Power Supply Specification* * Based on developing a performance specification (not build to print)

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

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.