Safe Handling of SRF Cavities

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• Safe Handling of SRF Cavities

Allan Rowe TD/SRFDD
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Outline

• Introduction
• Training Requirements
• Must-Read Document List
• Improper Cavity Handling Incidents Findings
• Fermilab and the SRF Technology Program
• Basic SRF Cavity Information
• General SRF Cavity Handling Guidelines
• 1.3 GHz One-cell Cavity Procedure
• 1.3 GHz Nine-cell Cavity Procedure
• Summary
• Questions Answers

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Training Requirements

• ITNA Question Will the individual be involved in
  the transport and/or handling of SRF cavities
  between Fermilab buildings and/or between
  Fermilab and other laboratories? checked.
• Safe Handling of SRF Cavities
• Course FN000434/CR
• Facility specific training and procedures.
• ICB, IB1, IB3, IB4
• CAF, MDB, NML
• A0, ANL-SCSPF
• Other appropriate training (Forklift, crane,
  walk-behind powered fork truck, etc.)
• Training Review Period 3 years

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Must-Read Documents

• Procedure for Inter-facility Transport and
  Handling of One-cell SRF Cavities
• TD Doc. No. OP-333950
• Procedure for Inter-facility Transport and
  Handling of Nine-cell SRF Cavities
• TD Doc. No. OP-333952
• Radio-Frequency Cavity Handling Guidelines
• TD Doc. No. OP-333951
• These controlled documents can be found here
• http//tdserver1.fnal.gov/tdweb/qm/OperationProced
  uresPage.asp
• Paper copies available upon request.
• Facility Specific Procedures See area
  supervisor

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JLab Handling Incident

• SRF cavity damaged due to improper handling
• What happened?
• Several years ago, JLab employee dropped a cavity
  while carrying it down stairs on shoulder.
• Employee lost footing on stairs, pitched forward
  off balance and let go of cavity.
• Cavity tumbled down the stairs onto the floor.
• Cavity severely damaged and employee safety put
  in dire risk.
• Lessons learned
• Cavalier handling in this incident unacceptable.
• Experience doesnt justify complacency.
• Proper handling and transport requirements and
  enforcement lacking.

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Fermilab Handling/Storage Incident

• 1.3 GHz 9-cell SRF cavity severely damaged due to
  improper handling and storage.
• What happened?
• V-block supports removed and replaced with foam.
• Cavity fell to floor storage position on top of
  rolling tool box.
• Both end cells and vacuum manifold severely
  damaged.

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Fermilab Incident Report

• Findings Many contributing factors.
• Inexperience in handling valuable SRF cavities
  partially led to poor decision making.
• No Hazard Analysis performed, either written or
  mental.
• Complete lack of risk assessment of any kind.
• No cavity protection of any kind. Choice of
  padding beneath cavity may have enhanced
  likelihood of rolling.
• Improper storage location on rolling tool chest
  chosen.
• No designated and controlled cavity storage
  location in facility.
• Lack of ownership or guidance as to the next
  steps for the cavity.
• No formal cavity handling or storage training
  specific to facility.

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Fermilab Incident Report

• Findings cont
• No formal cavity handling or storage procedures.
• Inadequate handling tooling and storage
  capability within facility.
• Communication breakdown between employee and
  supervisor. Supervisor unaware of risks and
  inexperienced in SRF cavity handling.
• Communication breakdown between facility staff
  and subsequent owners of the cavity. No formal
  cavity coordination.
• No specific person responsible for cavity flow.
• Many Findings common with some practices at other
  facilities! Hence the need for formalization
  and training.

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Fermilab and SRF Technology

• Background
• SRF is a cornerstone technology for Fermilabs
  future.
• Nearly all planned accelerators have SRF at the
  core.
• Substantial investment in SRF infrastructure.
• Full commitment to developing core competence in
  SRF.
• Progress from technology adapter to technology
  Leader.
• Highly developed RD program SRF
  Industrialization.

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Fermilab and SRF Technology

• Fermilabs responsibilities.
• Sole remaining HEP laboratory in US.
• Curator of SRF technology and funding for future
  HEP programs based on SRF.
• Must lead by example.
• Limit mistakes to absolute minimum.
• Formalization of processes, procedures and
  training.
• Complete and widespread mastery of basic SRF
  skills.
• Inexperience in SRF technology is no longer a
  viable excuse for mistakes.

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Basic SRF Cavity Information

• What is an RF cavity?
• Device used to accelerate charged particle beams.
• Particles get pushed or accelerated by electric
  fields in the cavity like a surfer gets pushed by
  strong waves.
• Energy from a powerful amplifier gets put into
  cavity via device called an RF coupler.
• Cavities are very carefully shaped to obtain
  exact electrical resonance.
• Why Superconducting RF?
• A Superconducting cavity has more than 100,000
  times fewer dissipation losses than a normal
  conducting cavity at the same gradient.
• All RF power can be transmitted to particle beam.
• World-wide panel decision favored SRF for ILC.

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SRF Cavity Characteristics
One -cell Nine -cell Nine -cell
Function RD RD, Production RD, Production
Material Content Niobium / NbTi Niobium / NbTi Niobium / NbTi
Material Characteristics Soft and malleablelike copper Soft and malleablelike copper Soft and malleablelike copper
Weight 15 lbs Bare 65 lbs
Weight 15 lbs Dressed 150 lbs
Length Up to 30 inches Up to 68 inches Up to 68 inches
Value 10-50k Bare 80-100k
Value 10-50k Dressed 250k
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Cavity Value Perspective

Processed One-Cell

New Nine-Cell

Dressed Nine-Cell
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Cavity Handling Requirements

• General GuidelinesOne-cells and Nine-cells
• Personal Protective Equipment
• Clean Nitrile or Latex gloves when contacting
  cavities, cavity frames, or other attached
  hardware.
• Manual lifting may require under-glove
  (leather/cotton) to protect hands from sharp
  edges. Over-glove to be clean Nitrile or Latex.
• Steel toed shoes.
• Facility specific PPE also required.
• Handling
• Cavities shall be handled in a manner to prevent
  plastic deformation (bending/denting) of the
  structure.
• Engineered lifting devices shall be used whenever
  possible to ensure personnel and equipment
  safety.

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Cavity Handling Requirements

• Handling cont
• Cavity ports shall be closed with protective caps
  or flanges except when the cavity processing
  requires these ports to be open.
• Cavity flange sealing surfaces shall be protected
  at all times during all processing steps.
• The internal cavity integrity shall be maintained
  in accordance with the process step requirements
• Cavities are often equipped with delicate RF
  couplers and feedthroughs. These devices shall
  be protected during cavity handling. Protective
  covers shall be utilized where appropriate.

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Cavity Handling Requirements

• Storage
• Cavities shall be stored in approved crates in
  low traffic areas designated by facility
  supervisors unless effectively secured in
  measurement, inspection, or processing tooling.
• Cavities and their frames must be stored in areas
  where they are not unduly exposed to dust, dirt,
  debris, grease, oils, or other detrimental
  contaminants.
• Transport
• Cavities shall be transported in approved crates.
• Cavities shall be secured in the transport
  vehicle by appropriate strapping and rigging to
  prevent movement under normal driving conditions.
• Laboratory vehicles shall be used for all on-site
  cavity transport and laboratory or commercial
  carrier for off-site transport.

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Cavity Handling Requirements

• Crates shall be labeled with the following
• Cavity content label showing cavity serial number
• Internal cavity condition (open, vacuum, Purged
  with Inert Gas)
• Fragile Stickers
• Cavity Sign-off Instructions
• The person responsible for transporting and/or
  receiving a cavity crate must electronically sign
  the Cavity Tracking Database verifying the
  following items prior to loading the transport
  vehicle
• Cavity crate contents and internal status.
• Location to be delivered.
• Person receiving cavity.
• This signature indicates a transfer of
  responsibility for the cavity to the receiver.

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Tracking and Sign-off Forms
Separate training required.
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One-cell Specific Requirements

• Handling
• One-cell cavities may be carefully moved by hand.
• One-cell crates may be moved by hand.
• Approved Crates for Storage and Transport
• Musical Instrument Style Bare, Dressed, 4-bar
  frame
• Wood box Bare cavities only.

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One-cell Crate Details

• Approved packing material is closed-cell
  polyethylene foam in 1 and 2 thick sheets
• Packaging guidelines are shown.

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Nine-cell Specific Requirements

• Handling
• Nine-cell crates may not be moved by hand.
  Specific exceptions are listed in the procedure.
• Nine-cell cavities shall be handled with tooling,
  crane slings, and fixtures designed for
  particular handling steps. Manual lifts cannot
  occur unless specifically approved.
• Nine-cell cavities shall be contained in 4-bar
  frames during handling to the extent possible.

Cavity installed in 4-bar frame
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Nine-cell Handling Techniques
Cavity movement with crane slung to 4-bar frame.
Bare cavity movement with crane slung between 2-3
and 7-8.
Standard Techniques
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Nine-cell Handling Techniques
Cavity movement by hand with 4-bar frame
Bare Cavity movement by hand
Pre-approved Techniques Only!
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Nine-cell Crate Details

• One standard storage and transport crate.
• Substitute crates possible. See procedure.
• Inner packing must be a minimum of 2 closed-cell
  polyethylene foam to encapsulate cavity.
• Packaging guidelines are shown.

Cavity in 4-bar Frame
Bare Cavity
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Nine-cell Crate Movement
Cavity crate movement with forklift
Cavity crate secured in Fermilab van
Transport to-from Argonne shown.
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Variance Requests

• In the rare case where the procedures described
  are not suitable, exception requests shall be
  filed with the SRF Development Department Head.
• A justification statement as to why the
  procedures are not appropriate as well as an
  alternative handling procedure and hazard
  analysis must be provided to receive the
  exception.
• Variance requests will be handled on a
  case-by-case basis.

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Summary

• SRF technology is vital to Fermilabs future.
• SRF cavities are very valuable and highly fragile
  despite appearance.
• Mistakes causing cavity damage must be minimized
  to the fullest extent possible.
• Process formalization required with increasing
  number of cavities.
• Personnel training and feedback mechanisms very
  important.
• Cavity ownership and responsibility delineations
  critical.
• Culture of SRF begins with mastery of critical
  skills like cavity transport and handling.