Spectrometer Solenoid Fabrication Status and Schedule Steve Virostek Lawrence Berkeley National Lab MICE RAL October 20, 2008

MICE Spectrometer Solenoid Fabrication Update and Schedule StatusPage 2 Steve Virostek -- Lawrence Berkeley National Laboratory -- October 20, 2008 MICE Cooling Channel Layout Spectrometer Solenoid #1 (complete but mods req’d) Spectrometer Solenoid #2 (ready for final assembly)

MICE Spectrometer Solenoid Fabrication Update and Schedule StatusPage 3 Steve Virostek -- Lawrence Berkeley National Laboratory -- October 20, 2008 First magnet completed; testing revealed several issues Frozen N 2 in cold mass helium lines prevented proper operation (mainly procedural, partially design issue) Inadequate thermal connection between 1st stage of cold heads and cold mass radiation shield No direct cooling of radiation shield (long cooldown) Venting of cold mass during quench is not sufficient due to crowding of vent line with instrumentation wires Mechanical issues: cold mass alignment, support stand height, iron shield support pads, support stand offset Second magnet ready for final assembly (w/improvements) Summary

MICE Spectrometer Solenoid Fabrication Update and Schedule StatusPage 4 Steve Virostek -- Lawrence Berkeley National Laboratory -- October 20, 2008 Magnet CMM Measurement Portable CMM used to make measurements of first magnet CMM to be used during reassembly to ensure proper alignment/height

MICE Spectrometer Solenoid Fabrication Update and Schedule StatusPage 5 Steve Virostek -- Lawrence Berkeley National Laboratory -- October 20, 2008 Magnet cool down accomplished using LN 2 & LHe Cool down is done slowly to control cold mass thermal stress (i.e. limited  T) Cold mass of first magnet reached LHe temperature with no observed problems Cold mass temperature could not be maintained with the cryocoolers (no re-condensing) Apparent blockage in LHe cooling line occurred due to freezing of LN 2 or air All five coils reached a maximum current of 196 amps during training Magnet Cool Down and Training

MICE Spectrometer Solenoid Fabrication Update and Schedule StatusPage 6 Steve Virostek -- Lawrence Berkeley National Laboratory -- October 20, 2008 Ice on magnet leads during cool down Magnet Cool Down Vent line Fill line

MICE Spectrometer Solenoid Fabrication Update and Schedule StatusPage 7 Steve Virostek -- Lawrence Berkeley National Laboratory -- October 20, 2008 Opening of Magnet #1 will be required to perform fixes Helium line blockage: increase LHe line  or connect directly to cryostat, eliminate traps, improve procedure Radiation shield connection: increase thermal conduction with thick 1100 Al flexible straps Cold mass vent: add additional vent line to the cold mass Radiation shield cooldown: incorporate LN reservoir to allow direct cooldown of shield Mechanical issues: realign Magnet #1 during reassembly (also corrects support stand height), modify end supports to clear iron shield mount pad (Magnets #1 and #2) Design Solutions

MICE Spectrometer Solenoid Fabrication Update and Schedule StatusPage 8 Steve Virostek -- Lawrence Berkeley National Laboratory -- October 20, 2008 Cryostat and Cooling System Mods Improved radiation shield connection Cold head 1 st stage Radiation shield Additional vent line Direct cryostat connection option

MICE Spectrometer Solenoid Fabrication Update and Schedule StatusPage 9 Steve Virostek -- Lawrence Berkeley National Laboratory -- October 20, 2008 Magnet Cooling Modifications Original Design Design Option 1 Cold head Condenser Cold mass shell Coils LHe line Trap Larger diameter No trap A written cooldown procedure will be generated to ensure that all N 2 is purged from the system prior to introducing liquid helium Design Option 2 Direct connection LHe

MICE Spectrometer Solenoid Fabrication Update and Schedule StatusPage 10 Steve Virostek -- Lawrence Berkeley National Laboratory -- October 20, 2008 Radiation Shield Thermal Connection Thicker 1100 series aluminum connection to thermal shield (previously thin copper)

MICE Spectrometer Solenoid Fabrication Update and Schedule StatusPage 11 Steve Virostek -- Lawrence Berkeley National Laboratory -- October 20, 2008 Liquid Nitrogen Reservoir LN reservoir Radiation shield Thermal plate connection 1 st stage cooler connection Vent/fill lines (3) Reservoir provides direct LN cooldown of shield Inproves thermal connection between 1 st stage of cryos and shield Frozen mass of nitrogen protects leads in event of power failure Reservoir may be empty during operation due to safety concerns

MICE Spectrometer Solenoid Fabrication Update and Schedule StatusPage 12 Steve Virostek -- Lawrence Berkeley National Laboratory -- October 20, 2008 Liquid Nitrogen Reservoir LN 2 reservoir to be thermally connected to radiation shield Plates welded to radiation shield for reservoir connection

MICE Spectrometer Solenoid Fabrication Update and Schedule StatusPage 13 Steve Virostek -- Lawrence Berkeley National Laboratory -- October 20, 2008 Cold mass and vacuum vessel are misaligned by ~10mm vertically CMM to be used to correct alignment during magnet reassembly Support stand beams interfere with lower iron shield saddle plate Supports will be modified at both ends of both magnets Support stands welded in place with a ~100 mm shift from nominal Interface drawing being prepared showing mount locations Diffuser mounting flange is in place but w/no mounting holes Tapped holes in flange to be added in field to match diffuser Support structure may not be adequate to support axial loads re-analysis is under way; some reinforcement may be needed Mechanical Issues and Planned Fixes

MICE Spectrometer Solenoid Fabrication Update and Schedule StatusPage 14 Steve Virostek -- Lawrence Berkeley National Laboratory -- October 20, 2008 Support stand cross beams interfere with the planned location of the lower iron shield saddle plate Spoort Stand Modification Area of interference

MICE Spectrometer Solenoid Fabrication Update and Schedule StatusPage 15 Steve Virostek -- Lawrence Berkeley National Laboratory -- October 20, 2008 Support Stand Modification Vacuum vessel Support braces Iron shield lower mount and pad Original Design Modified Design New braces Change order placed w/vendor to modify both ends of both magnets

MICE Spectrometer Solenoid Fabrication Update and Schedule StatusPage 16 Steve Virostek -- Lawrence Berkeley National Laboratory -- October 20, 2008 Second Magnet Assembly Second magnet nearly ready for final assembly Improved thermal shield connection incorporated Second cryostat vent tube added LN reservoir complete and ready to install Cooling circuit mod to be completed soon

MICE Spectrometer Solenoid Fabrication Update and Schedule StatusPage 17 Steve Virostek -- Lawrence Berkeley National Laboratory -- October 20, 2008 Magnet Discharge Circuit Rapid discharge circuit designed and fabricated by Wang NMR Each magnet will have a dedicated circuit The water cooled, aluminum body assemblies are rack mounted Water cooling is only needed during and after a discharge

MICE Spectrometer Solenoid Fabrication Update and Schedule StatusPage 18 Steve Virostek -- Lawrence Berkeley National Laboratory -- October 20, 2008 The plan to move forward involves completing Magnet #2 first with all proposed design changes Upon shipping of Magnet #2 (now first unit), Magnet #1 will be opened, and the cryostat removed for modification (reconfigure cooling, add vent line, LN reservoir, etc.) The current goal for completing the first unit (Magnet #2) including cooldown and test is the end of November The reassembly and completion of Magnet #1 should follow by approximately two months Two iron shield assemblies are being fabricated and are close to completion (to be delivered to FNAL) Schedule

MICE Spectrometer Solenoid Fabrication Update and Schedule StatusPage 19 Steve Virostek -- Lawrence Berkeley National Laboratory -- October 20, 2008 Testing of 1st magnet revealed several problems Blocked LHe line between coolers and cold mass Inadequate thermal connection to radiation shield No direct cooling of shield in original design Inadequate venting of cold mass during quench Several mechanical issues to be addressed Second magnet proceeding (w/improvements) Summary