Spectrometer Solenoid Spectrometer Solenoid Test Plan Workshop: Test Plan Workshop:
Spectrometer Solenoid Spectrometer Solenoid OverviewOverview
Steve Virostek - LBNLSteve Virostek - LBNL
February 17, 2012
LBNL
Spectrometer Solenoid Test Plan Workshop - 2/17/2012
- 2 -Magnet Overview Steve Virostek LBNL
TopicsTopics
• Overview of the Spectrometer SolenoidsOverview of the Spectrometer Solenoids• Key magnet requirementsKey magnet requirements• Recent magnet operationRecent magnet operation• Design modificationsDesign modifications
Heat reduction to 4.2KHeat reduction to 4.2K Radiation shield improvementsRadiation shield improvements Cryocooling powerCryocooling power Other improvementsOther improvements
LBNL
Spectrometer Solenoid Test Plan Workshop - 2/17/2012
- 3 -Magnet Overview Steve Virostek LBNL
MICE Cooling Channel LayoutMICE Cooling Channel Layout
Spectrometer Solenoid #1
Spectrometer Solenoid #2
LBNL
Spectrometer Solenoid Test Plan Workshop - 2/17/2012
- 4 -Magnet Overview Steve Virostek LBNL
Performance OverviewPerformance Overview
• Key magnet requirements:Key magnet requirements:All five coils must be trained to 275 ampsAll five coils must be trained to 275 ampsThe cryocoolers must maintain the LHe in the The cryocoolers must maintain the LHe in the
cold mass (no boil-off)cold mass (no boil-off)
Not yet achieved for either magnet
LBNL
Spectrometer Solenoid Test Plan Workshop - 2/17/2012
- 5 -Magnet Overview Steve Virostek LBNL
Magnet 2B OperationMagnet 2B Operation• A single-stage cooler had been added to increase A single-stage cooler had been added to increase
cooling at the HTS lead upper ends and to help reduce cooling at the HTS lead upper ends and to help reduce the shield temperaturethe shield temperature• Magnet 2B was trained in series to 258 amps when a Magnet 2B was trained in series to 258 amps when a
coil lead was found to contain an open circuitcoil lead was found to contain an open circuit• The failure was traced to the M2 coil close to the The failure was traced to the M2 coil close to the
He/vacuum feedthru He/vacuum feedthru • Training on the Center, E1 and E2 coils in series Training on the Center, E1 and E2 coils in series
continued, reaching 270 ampscontinued, reaching 270 amps• During operation, the 3+1 cooler configuration could During operation, the 3+1 cooler configuration could
not maintain a closed LHe systemnot maintain a closed LHe system
LBNL
Spectrometer Solenoid Test Plan Workshop - 2/17/2012
- 6 -Magnet Overview Steve Virostek LBNL
Magnet 2B Cross SectionMagnet 2B Cross Section
LBNL
Spectrometer Solenoid Test Plan Workshop - 2/17/2012
- 7 -Magnet Overview Steve Virostek LBNL
Added Single Stage CoolerAdded Single Stage Cooler
LBNL
Spectrometer Solenoid Test Plan Workshop - 2/17/2012
- 8 -Magnet Overview Steve Virostek LBNL
Magnet 2B DisassemblyMagnet 2B Disassembly
• After warm-up, the cold mass was removed from the After warm-up, the cold mass was removed from the vacuum vessel and openedvacuum vessel and opened
• The failed lead was located just inside the cold mass The failed lead was located just inside the cold mass feedthrough feedthrough
• Analysis indicated that the conductor adjacent to the Analysis indicated that the conductor adjacent to the feedthru needed stabilization against movement and feedthru needed stabilization against movement and for enhanced coolingfor enhanced cooling
• The internal quench resistors in Magnet 2B were found The internal quench resistors in Magnet 2B were found to be damaged due to overheatingto be damaged due to overheating
• Magnet 1 resistors were not damagedMagnet 1 resistors were not damaged
LBNL
Spectrometer Solenoid Test Plan Workshop - 2/17/2012
- 9 -Magnet Overview Steve Virostek LBNL
Subsequent AnalysesSubsequent Analyses
• The heat leaks from dominant static sources The heat leaks from dominant static sources were re-evaluated, focusing on heat leaks to were re-evaluated, focusing on heat leaks to 4.2K (LHe boil-off issue)4.2K (LHe boil-off issue)• Other operational aspects considered: heat Other operational aspects considered: heat
loads on the shield and vacuum insulationloads on the shield and vacuum insulation• The design of the passive magnet protection The design of the passive magnet protection
system design was also analyzed under various system design was also analyzed under various operational regimesoperational regimes
LBNL
Spectrometer Solenoid Test Plan Workshop - 2/17/2012
- 10 -Magnet Overview Steve Virostek LBNL
Design Modification ApproachDesign Modification Approach
• The design and assembly modification plan The design and assembly modification plan was developed based on the following:was developed based on the following:reduction of heat leaks to the cold massreduction of heat leaks to the cold massthe addition of more cryo cooling powerthe addition of more cryo cooling powermodification of the cold leads near the modification of the cold leads near the
feedthroughs to prevent burn-outfeedthroughs to prevent burn-outthermal heat sinking of the quench resistorsthermal heat sinking of the quench resistors
• Details provided on the following slidesDetails provided on the following slides
LBNL
Spectrometer Solenoid Test Plan Workshop - 2/17/2012
- 11 -Magnet Overview Steve Virostek LBNL
4.2K Heat Load Reduction4.2K Heat Load Reduction
• Improved vacuum pumping and instrumentationImproved vacuum pumping and instrumentation
• 4K areas covered with actively cooled shield where 4K areas covered with actively cooled shield where possiblepossible
• Baffles added to vent lines to prevent radiation shine Baffles added to vent lines to prevent radiation shine to 4.2Kto 4.2K
• Possible thermal acoustic oscillations in vent/fill lines Possible thermal acoustic oscillations in vent/fill lines to be monitored w/pressure gaugesto be monitored w/pressure gauges
• Improved application of MLI on cold massImproved application of MLI on cold mass
• Sensor wires optimized & w/proper heat sinkingSensor wires optimized & w/proper heat sinking
LBNL
Spectrometer Solenoid Test Plan Workshop - 2/17/2012
- 12 -Magnet Overview Steve Virostek LBNL
Radiation Shield ImprovementsRadiation Shield Improvements
• Radiation shield remade w/6.35 mm thick 1100 series Radiation shield remade w/6.35 mm thick 1100 series aluminum (except for the inner bore) – previously 6061aluminum (except for the inner bore) – previously 6061
• Improved thermal connection between cooler first Improved thermal connection between cooler first stage and radiation shield (copper sheets vs. aluminum stage and radiation shield (copper sheets vs. aluminum tubes)tubes)
• Application of MLI on shield improvedApplication of MLI on shield improved
• Heat loads decreased as possible: shield pass-through Heat loads decreased as possible: shield pass-through holes for the cold mass supports, intermediate cold holes for the cold mass supports, intermediate cold mass support heat intercepts, and shielding of the mass support heat intercepts, and shielding of the warm end of the supportswarm end of the supports
LBNL
Spectrometer Solenoid Test Plan Workshop - 2/17/2012
- 13 -Magnet Overview Steve Virostek LBNL
Quench Resistor Heat SinkingQuench Resistor Heat Sinking
LBNL
Spectrometer Solenoid Test Plan Workshop - 2/17/2012
- 14 -Magnet Overview Steve Virostek LBNL
Other Design ModificationsOther Design Modifications
• Other key improvements:Other key improvements: Total cooling power increased to five 2-stage pulsed tube Total cooling power increased to five 2-stage pulsed tube
coolers and one single-stage coolercoolers and one single-stage cooler Extra copper/superconductor added near cold mass Extra copper/superconductor added near cold mass
feedthroughs for increased cold lead stabilityfeedthroughs for increased cold lead stability
• Other improvements/additions:Other improvements/additions: LBNL/MICE personnel assisting with magnet reassemblyLBNL/MICE personnel assisting with magnet reassembly Detailed MLI inspection carried out during assemblyDetailed MLI inspection carried out during assembly Fast DAQ system will continuously monitor voltage tapsFast DAQ system will continuously monitor voltage taps Additional temperature sensors added to the logging systemAdditional temperature sensors added to the logging system
LBNL
Spectrometer Solenoid Test Plan Workshop - 2/17/2012
- 15 -Magnet Overview Steve Virostek LBNL
5 + 1 Cryocooler Layout5 + 1 Cryocooler Layout