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Progress on the MICE Cooling Channel and Tracker Magnets

Progress on the MICE Cooling Channel and Tracker Magnets. Michael A. Green Lawrence Berkeley Laboratory. AFC Module 2. RFCC Module 1. Tracker Module 2. AFC Module 3. AFC Module 1. RFCC Module 1. Tracker Module 1. MICE Channel with the Trackers. Drawing by S. Q. Yang, Oxford University.

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Progress on the MICE Cooling Channel and Tracker Magnets

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  1. Progress on the MICECooling Channel and Tracker Magnets Michael A. Green Lawrence Berkeley Laboratory NFMCC Meeting, IIT, Chicago

  2. AFC Module 2 RFCC Module 1 Tracker Module 2 AFC Module 3 AFC Module 1 RFCC Module 1 Tracker Module 1 MICE Channel with the Trackers Drawing by S. Q. Yang, Oxford University NFMCC Meeting, IIT, Chicago

  3. Summary of the MICE Magnet Changessince the last NFMCC Meeting • The baseline magnet lattice has been changed slightly. There may be other small changes in the tracker magnet system. • Since the NFMCC meeting, there have been no changes in the AFC magnet and the coupling magnet, but discussions with vendors suggest that changes may be needed. • The tracker solenoid has been designed and a specification has been written. The RFP will go out soon. • As a result of discussions with magnet vendors, the magnet design may move toward indirect cooling with LHe in pipes. • Further work has been done on the worst case longitudinal magnetic forces in MICE. • The field at the cooler determines what type of cooler to use. NFMCC Meeting, IIT, Chicago

  4. The MICE AFC Module Courtesy of S. Q. Yang, Oxford University NFMCC Meeting, IIT, Chicago

  5. Gas He Pipe Coil Cover Plate S/C Coil #1 S/C Coil #2 LH2 Absorber Hydrogen Window LH2 Pipes Safety Window Magnet Mandrel Liquid Helium Feed Pipe The Center of the MICE AFC Module Courtesy of S. Q. Yang, Oxford University NFMCC Meeting, IIT, Chicago

  6. The Focusing Magnet Aspects of the AFC Magnet The cooling of the AFC magnet will probably change from liquid on the outside of the coils to liquid in tubes attached to the coils. This changes some of the pressure vessel code design issues. The HTS leads will be located in the cryostat vacuum space. The copper lead design current is 250 A. The AFC magnet cold mass support system is designed for 50 tons in the longitudinal direction. AFC Magnet October 27, 2005 Drawing by S. Q. Yang, Oxford University NFMCC Meeting, IIT, Chicago

  7. Cavity RF Coupler Coupling Magnet Dished Be Window RF Cavity Module Vacuum Vessel Magnet Vacuum Vessel Vacuum Pump The MICE RFCC Module Courtesy of S. Q. Yang, Oxford University NFMCC Meeting, IIT, Chicago

  8. The Coupling Magnet Aspects of the Coupling Magnet The cooling of the coupling magnet May change from liquid helium on the outside of the coils to liquid helium in tubes attached to the coils. This changes some of the pressure vessel code design issues. The HTS leads will be located in the cryostat vacuum space. The copper lead design current is 230 A. The magnet cold mass support system is designed for a longitudinal force of 50 tons. Quarter Section of RFCC Module Drawing by S. Q. Yang, Oxford University NFMCC Meeting, IIT, Chicago

  9. End Coil 2 Coil Cover End Coil 1 Match Coil 1 690 mm 2544 mm Center Coil 490 mm Liquid Helium Space Match Coil 2 Coil Spacer Courtesy of S. Q. Yang, Oxford University Tracker Solenoid Cold Mass NFMCC Meeting, IIT, Chicago

  10. 300 K Support End Cold Mass Assembly 60 K Support Intercept Support Band 4 K Support End Tracker Solenoid 50 Ton Longitudinal Force Cold Mass Support System Courtesy of S. Q. Yang, Oxford University NFMCC Meeting, IIT, Chicago

  11. Magnet Cooler Magnet Leads Condenser Box Cold Mass Support Cold Mass Assembly Liquid Helium Pipe Helium Gas Pipe Tracker Magnet Cold Mass, Coolers Cryogenic Distribution System Courtesy of S. Q. Yang, Oxford University NFMCC Meeting, IIT, Chicago

  12. Changes in the Cryogenic System • The high temperature superconductor (HTS) leads may have to operate in a vacuum (depends the on type of lead). The lead vacuum-tight feed through problem is not trivial. • A number of the vendors suggest that the MICE coils should be cooled indirectly (using liquid helium in tubes). This is OK as long as the tube area is large enough. • Changing from having a liquid reservoir in the cold mass assembly to liquid helium in tubes will change the pressure vessel code design of the magnet cold mass. The only part of the helium system that comes under the pressure vessel code is the condenser box at the bottom of the magnet coolers. NFMCC Meeting, IIT, Chicago

  13. Power Supply Specification • The power supply design current is +300 A at ±10 V. This is a two quadrant power supply with current regulation of better than ±0.01 percent over a current range from 50 A to 275 A. The highest currents are in tracker coils. There will be be at least six of these power supplies. • The small power supply design current is ±50 A at ±5 V. This is a four quadrant power supply with current regulation of better than ±0.03 percent over a range of currents from 5 to 45 A. There will be at least four of these power supplies. NFMCC Meeting, IIT, Chicago

  14. Focusing and Coupling magnet Hookup NFMCC Meeting, IIT, Chicago

  15. Tracker Magnet Hookup E2 M1 E2 C E1 M2 M1 M2 E1 C NFMCC Meeting, IIT, Chicago

  16. Coupling Coefficients between Coils Magnet Circuit Self Inductance and the Mutual Inductances in the Flip Mode Magnet Circuit Self Inductance and the Mutual Inductance in the Non-flip Mode NFMCC Meeting, IIT, Chicago Courtesy of H. Witte, Oxford University

  17. Forces with MICE Magnet Quenches Both Tracking magnets quench together. Only one coupling magnet will quench. The three focusing magnets will quench together. See MICE Note 107 with the magnet lattice of August 2004. NFMCC Meeting, IIT, Chicago

  18. “Hey dummy, you reversed the leads 1.” Baseline MICE Lattice as of March 2006, when p = 200 MeV/c and b = 420 mm. The highest forces are in the focusing coils when the coupling coil leads are reversed. NFMCC Meeting, IIT, Chicago

  19. “Hey dummy, you reversed the leads 2.” Baseline MICE Lattice as of March 2006, when p = 200 MeV/c and b = 420 mm. The highest forces are in the end focusing coils when the M1 leads are reversed. NFMCC Meeting, IIT, Chicago

  20. Peak Longitudinal Forces • The peak longitudinal forces on the focus coils will occur when p = 240 MeV and b = 420 mm in the flip mode, with the leads reversed. The peak force is about 68 tons on the end focusing magnets, when one or both coupling magnets are reversed. When the M1 coils are reversed, the peak force on the end focus coils is about 54 tons in the flip mode. The MICE magnet polarity must be checked before going to high momenta (currents in the coils). • In the non-flip mode the peak force on the focusing magnet is about 46 tons with the leads reversed. Similar forces may be found in the tracker magnets. More work is needed to show what the peak forces are in all of the magnets. NFMCC Meeting, IIT, Chicago

  21. Axial Field outside around the Tracker VLPC Cooler Location B = 0.02 to 0.045 T Cooler Location B = 0.085 to 0.145 T From Holger Witte at Oxford University NFMCC Meeting, IIT, Chicago

  22. Radial Field outside around the Tracker VLPC Cooler Location B = 0.02 to 0.045 T Cooler Location B = 0.085 to 0.145 T From Holger Witte at Oxford University NFMCC Meeting, IIT, Chicago

  23. Radial Field outside the AFC Module Magnet & Absorber Cooler Location B = 0.35 to 0.5 T From Holger Witte at Oxford University NFMCC Meeting, IIT, Chicago

  24. Axial Field outside the RFCC Module Rotary Valve Location B = ~0 to 0.2 T Cooler Location B = 1.0 to 2.0 T From Holger Witte at Oxford University NFMCC Meeting, IIT, Chicago

  25. Comments on Cooler Location and theType of Cooler to be used • The field at the coolers for the tracker magnet is about ~0.1 T. If the coolers are moved out about 0.1 meters, GM coolers can be used for this magnet. • The field at the coolers for the AFC module is about 0.3 to 0.5 T. This is too high for using a GM cooler without a large iron shield. Use pulse tube coolers with shielded rotary slide valves. • The field at the cooler for the RFCC module is ~1.5 T. This is too high for a GM cooler. Use a pulse tube cooler with a remote shielded rotary slide valve. • The VLPC coolers can be GM coolers, because the field is less than 0.05 T NFMCC Meeting, IIT, Chicago

  26. Concluding Comments • It appears that indirect cooling (liquid helium in tubes) will be used for all of the MICE magnets. • The performance of the match coils for the MICE tracker magnet is not understood. The actual vendor magnet design will be determine the final match coil operating currents. • The peak longitudinal forces occur at 240 MeV/c in the flip mode. These forces occur in the focusing magnets when the coupling coil leads are reversed. The coil lead polarity must be checked before going to high currents. • Two types of power supplies will be used on MICE. The large supply is 300 A at ±10 V. The small supply is ±50 A at ±5 V. • Pulse tube coolers will be used on all of the MICE magnets. NFMCC Meeting, IIT, Chicago

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