1. MICE Superconducting Solenoids: Status and Update RAL: T W Bradshaw M Courthold J Rochford M Hills D Baynham Oxford: J Cobb W Lau S Yang 2010-06-08 MICE Superconducting Solenoids TWB.pptx Berkeley: M Green S Virostek M Zisman Harbin: H Pan X K Liu L Wang X L Guo H Wu A B Chen

2. Introduction Brief overview of the magnet system Status of the coils Coil#Sponsor Decay Solenoid1PSI (Switzerland) UK integration installation and commissioning of helium plant Absorber and Focus Coil 3UK – Oxford University and Rutherford Appleton Laboratory – built in UK Spectrometer Solenoids 2US LBNL – built in US Coupling coils (flip coils) 2US LBNL – built in China Harbin Institute of Cryogenics and Super Conductivity Technology Upstream on Beam Line (not part of cooling channel)

3. Magnet Positions Position of the Magnets in the MICE Hall

4. Decay Solenoid Component of the beam line so not part of the MICE lattice Installed in wall of MICE hall Unusual in that is cooled with supercritical helium at 4.5K Field 5T at 870A 1.1MJ Area 1.8x3.2mm 2 Cu:Sc 3.5 Icritical 1000 A Bcrit (from model) 5.9T So Jcrit of superconductor 781A/mm 2 @ 5.9T and ~4.2K Solenoid in hall at PSI This was used on a muon channel at PSI and was operated from December 1974 until 2004

5. Decay Solenoid –5T Superconducting Solenoid –115mm bore, 5000mm length, constructed from 10 spools –Designed and built at the Paul Scherrer Institut (PSI) in the 1970s –Cooled by supercritical helium gas to approx. 4.8K –Critical current at 4.8K = 1000A, require 870A for 5T –Requires approx. 23W of cooling power

6. Decay Solenoid –Transfer Line comprises 4 vacuum jacketed process lines (4K feed and return + 70K feed and return) –Many metres of ancillary pipework between cold box, decay solenoid and the gas panels –Buffer Tank stores the make-up gas required as liquid is formed in the magnet –Magnet Current provided by 4 large cables between the power supply on the north mezzanine and the magnet turret

7. Decay Solenoid Part of the solenoid radioactive when supplied from PSI Replaced “hot” outer nose Work on plumbing, power supplies, quench detection.... Refrigerator supplied from Linde System worked well until we had the refrigerator serviced – leaks, gas purity etc..........but now back in operation

8. MICE Lattice Spectrometer Absorber Focus Coil Coupling Coil Note – all magnets in lattice use closed cycle coolers for refrigeration

9. MICE Lattice SS AFC CC AFC CC AFC SS

10. Spectrometer Solenoid This is the most complicated of the MICE coils Comprises 1 x centre coil 2 x end coils 2 x matching coils

11. Spectrometer Solenoid Magnet has been run at Wang NMR with training as follows 165, 219, 238, 253, 257 A (required current is 275A) M2 coil open circuit between feed-through on the internal cryostat and the coil. Magnet is now being disassembled and review board convened to assess the problems The other spectrometer solenoid (#1!) is awaiting final assembly This will cause a delay while the problems are being understood

12. Absorber and Focus Coil The Absorber and Focus Coil Solenoid consists of two coils on a bobbin Has to accommodate the hydrogen absorber and safety windows Closed cycle coolers used on both the magnet system and the hydrogen condensing system

13. Absorber and Focus Coil Status Completed reviews prior to manufacture Thermal model Mechanical issues around bobbin material and strength Quench protection etc.... Just entering the manufacturing phase with the first coil to be wound in the next few weeks. First delivery Jan 2011 Second delivery April/May 2011 Third ??? (required 2013)

14. Coupling Coils In the process of manufacture by Harbin Institute of Cryogenics and Super Conductivity Technology under contract from Lawrence Berkeley These will be integrated with 201MHz RF cavities to form the RFCC – RF coupling coil modules. Length 285mm Inner rad750mm Layers96 Inductance593 H Current210/198A (flip/non flip) Status: Design complete In manufacture Because of large stray field position and orientation of HTS leads important – need to keep field // to the flat face of the conductor

15. Summary The components of the MICE lattice and beam line are in various stages of manufacture and production MICE – unusual for a particle physics experiment in that all the magnets are cooled by cryocoolers Decay solenoid – in position and operational Spectrometer solenoids – due early 2011 – on critical path Absorber and focus coils – first one Jan 2011 (required Q3 for Step IV) Coupling coils – required 2012 for Step V (with one rf module)

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