Superconducting Magnet Support for the Tevatron in Run II

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Superconducting Magnet Supportfor the Tevatron
in Run II

• David Harding
• 25 April 2002

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Fermilab Operates the Highest Energy Particle
Accelerator in the World
1267 Superconducting magnets
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Superconducting Magnet WorkSupporting the
Tevatron

• Upgrades
• Improve performance
• Improve reliability
• Maintenance
• Manage inventory of spare magnets
• Execute repairs as needed
• Measurements
• Adjust rebuilt magnets in production
• Certify new, repaired magnets
• Characterize performance

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Superconducting Magnet Program Resources Needed
to Support Run II (1)

• Good records
• Inventory
• What devices do we have?
• Status, grade
• Engineering documents
• Device drawings
• Documented procedures (travelers)
• Historical records (old travelers)
• Measurement data
• Quench performance
• Field strength and quality
• Special measurements

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Superconducting Magnet Program Resources Needed
to Support Run II (2)

• Components
• Stock of commonly used and long lead time parts
• Reserve of major subassemblies

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Superconducting Magnet Program Resources Needed
to Support Run II (3)

• Facilities
• Production facilities
• Measurement Facilities
• Cryogenic systems
• Power systems
• Instrumentation
• Data storage

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Superconducting Magnet Program Resources Needed
to Support Run II (4)

• Trained, talented people!
• Engineers familiar Tevatron devices
• Technicians familiar with Tevatron devices
• Procurement staff able to respond promptly
• Inspectors available as needed
• Measurement and cryogenic personnel with
  experience
• Clerical and computer support
• Committed physicists
• Steady state need for personnel is modest
• Reserve to draw upon in emergency is essential

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Recent Upgrade Projects

• Retrofit selected spools with Recoolers
• Lower temperature of 1-phase helium in ring with
  heat exchangers to enhance performance of
  accelerator
• Retrofit power feed spools with high temperature
  superconducting leads
• Improve helium management
• Develop experience with high temperature
  superconductor
• Replace spool corrector lead feed-throughs
• Reduce helium leaks
• Improve reliability

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Heat Exchanger Being Added to Spool

• Engineering
• Prototype built and studied
• Initial 14 spools complete
• Spools installed and work as advertised

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High Temperature Superconducting Power Leads

• Engineering
• Two spools retrofitted and studied as RD project
• Two vendors
• One spool installed
• More spools being retrofit as Accelerator
  Improvement Project
• Two done (second in testing)
• Will continue as spools become available

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Retrofitting Corrector Leads

• Engineering prototypes
• Install on spools in tunnel
• 10 of 24 houses retrofitted
• Intense effort in limited access periods
• Further work dependent on access
• Two technical issues being addressed

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Approach to Maintenance

• Manage a pool of spares
• Good magnets
• Awaiting repair
• When the pool falls below the specified threshold
• Repair enough magnets to restore the level agreed
  upon
• Start with the easiest work, best performing
  devices
• This requires
• Good records
• An inventory of parts
• Production and test facilities
• Trained technicians, engineers, physicists,
  support staff
• Need depth to respond to crisis

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Dipoles

• Dipoles come and dipoles go from the tunnel for
  several reasons
• Shuffling to match performance to temperature
• Leaks of various kinds
• Leads incorrectly connected
• Problems are at the ends and most can be repaired
• Long term history
• Permanently lose one magnet/year.
• If trend continues, we should be OK through Run
  II
• Extra stresses due to higher energy running
• No evidence of problems to date
• Old age???

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Tevatron Dipole in Need of Attention
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Tevatron Dipole Inventory
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Arc Quadrupoles

• Little movement of quadrupoles
• Long term history
• Have permanently lost only one magnet in last
  decade
• If trend continues, we should be OK through Run
  II
• Extra stresses due to higher energy running
• No evidence of problems to date
• Old age???

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Tevatron Quadrupole Inventory
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Low Beta Quadrupoles

• At least one spare for each device
• At least one spare cold mass for all but one
  device
• But Q2 and Q4 share a spare cold mass
• Magnets have suffered relatively minor insults
  and been repaired in varying amounts of time
• If trend continues, we should be OK through Run
  II
• Not as much history as with arc magnets
• Small numbers imply vulnerability to multiple
  failures
• Fear of degradation

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Typical Low Beta Q3 Repair
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Tevatron Low Beta Inventory
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Spools

• Many varieties
• Various combinations of corrector packages
• Safety leads
• Power leads
• Special locations
• Vacuum breaks
• Thermometry
• Few spare correctors (cold masses) left
• Some flexibility in use of spools

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Spool Safety Lead Failure
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Tevatron Spool Inventory
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Measurements at MTF

• Purposes of Measurements
• Final production trimming
• Qualify
• Characterize
• Types of Measurements
• Quench performance
• Harmonic composition of field
• Time dependence of field
• Magnetic center
• Heat leak

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Summary

• Support for Run II Is Essential
• Magnet upgrades are useful
• Failures happen and must be repaired
• Measurements are needed
• Technical Division and Beams Division are
  studying Tevatron vulnerabilities
• The Fermilab superconducting magnet program is
  ready to implement any recommendations
• More spares
• New magnets
• A healthy program is necessary to support Run II