1. 12 March 2006NFMCC Meeting, IIT, Chicago1 Progress on the MICE Cooling Channel and Tracker Magnets Michael A. Green Lawrence Berkeley Laboratory

2. 12 March 2006NFMCC Meeting, IIT, Chicago2 MICE Channel with the Trackers Drawing by S. Q. Yang, Oxford University Tracker Module 1 Tracker Module 2 AFC Module 1 AFC Module 3 AFC Module 2 RFCC Module 1

3. 12 March 2006NFMCC Meeting, IIT, Chicago3 Summary of the MICE Magnet Changes since 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.

4. 12 March 2006NFMCC Meeting, IIT, Chicago4 Courtesy of S. Q. Yang, Oxford University The MICE AFC Module

5. 12 March 2006NFMCC Meeting, IIT, Chicago5 Magnet Mandrel Safety Window LH 2 Pipes Liquid Helium Feed Pipe Gas He Pipe Hydrogen Window S/C Coil #1 LH 2 Absorber S/C Coil #2 Coil Cover Plate The Center of the MICE AFC Module Courtesy of S. Q. Yang, Oxford University

6. 12 March 2006NFMCC Meeting, IIT, Chicago6 The Focusing Magnet AFC Magnet October 27, 2005 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. Drawing by S. Q. Yang, Oxford University

7. 12 March 2006NFMCC Meeting, IIT, Chicago7 Coupling Magnet Cavity RF Coupler Dished Be Window RF Cavity Module Vacuum Vessel Vacuum Pump Magnet Vacuum Vessel The MICE RFCC Module Courtesy of S. Q. Yang, Oxford University

8. 12 March 2006NFMCC Meeting, IIT, Chicago8 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. Aspects of the Coupling Magnet Quarter Section of RFCC Module Drawing by S. Q. Yang, Oxford University

9. 12 March 2006NFMCC Meeting, IIT, Chicago9 End Coil 2 Center Coil Match Coil 1 End Coil 1 Match Coil 2 Coil Cover Liquid Helium Space 490 mm 690 mm 2544 mm Coil Spacer Tracker Solenoid Cold Mass Courtesy of S. Q. Yang, Oxford University

10. 12 March 2006NFMCC Meeting, IIT, Chicago10 Tracker Solenoid 50 Ton Longitudinal Force Cold Mass Support System 300 K Support End 60 K Support Intercept Support Band 4 K Support End Cold Mass Assembly Courtesy of S. Q. Yang, Oxford University

11. 12 March 2006NFMCC Meeting, IIT, Chicago11 Tracker Magnet Cold Mass, Coolers Cryogenic Distribution System Magnet Cooler Condenser Box Cold Mass Support Helium Gas Pipe Liquid Helium Pipe Cold Mass Assembly Magnet Leads Courtesy of S. Q. Yang, Oxford University

12. 12 March 2006NFMCC Meeting, IIT, Chicago12 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.

13. 12 March 2006NFMCC Meeting, IIT, Chicago13 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.

14. 12 March 2006NFMCC Meeting, IIT, Chicago14 Focusing and Coupling magnet Hookup

15. 12 March 2006NFMCC Meeting, IIT, Chicago15 Tracker Magnet Hookup M1 M2 E1 E2 CC

16. 12 March 2006NFMCC Meeting, IIT, Chicago16 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 Courtesy of H. Witte, Oxford University

17. 12 March 2006NFMCC Meeting, IIT, Chicago17 Forces with MICE Magnet Quenches See MICE Note 107 with the magnet lattice of August 2004. The three focusing magnets will quench together. Both Tracking magnets quench together. Only one coupling magnet will quench.

18. 12 March 2006NFMCC Meeting, IIT, Chicago18 “Hey dummy, you reversed the leads 1.” Baseline MICE Lattice as of March 2006, when p = 200 MeV/c and  = 420 mm. The highest forces are in the focusing coils when the coupling coil leads are reversed.

19. 12 March 2006NFMCC Meeting, IIT, Chicago19 “Hey dummy, you reversed the leads 2.” Baseline MICE Lattice as of March 2006, when p = 200 MeV/c and  = 420 mm. The highest forces are in the end focusing coils when the M1 leads are reversed.

20. 12 March 2006NFMCC Meeting, IIT, Chicago20 Peak Longitudinal Forces The peak longitudinal forces on the focus coils will occur when p = 240 MeV and  = 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.

21. 12 March 2006NFMCC Meeting, IIT, Chicago21 Axial Field outside around the Tracker Cooler Location B = 0.085 to 0.145 T From Holger Witte at Oxford University VLPC Cooler Location B = 0.02 to 0.045 T

22. 12 March 2006NFMCC Meeting, IIT, Chicago22 Radial Field outside around the Tracker Cooler Location B = 0.085 to 0.145 T From Holger Witte at Oxford University VLPC Cooler Location B = 0.02 to 0.045 T

23. 12 March 2006NFMCC Meeting, IIT, Chicago23 Radial Field outside the AFC Module Magnet & Absorber Cooler Location B = 0.35 to 0.5 T From Holger Witte at Oxford University

24. 12 March 2006NFMCC Meeting, IIT, Chicago24 Axial Field outside the RFCC Module Cooler Location B = 1.0 to 2.0 T From Holger Witte at Oxford University Rotary Valve Location B = ~0 to 0.2 T

25. 12 March 2006NFMCC Meeting, IIT, Chicago25 Comments on Cooler Location and the Type 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

26. 12 March 2006NFMCC Meeting, IIT, Chicago26 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.