Proposal for New Configuration of supporting SC Cavities on HGR pipe

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Proposal for New Configuration of supporting SC
Cavities on HGR pipe

• Prashant Khare
• R.K.Khare
• Vikas Jain

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Concept HGR Pipe Design for Manufacturing

• At present HGR pipe supports all cavities in a
  cryomodule.
• HGR pipe is manufactured with great precision as
  cavity alignment depends on it.
• Required straightness 3 mm in 12 m.length
• Hence expensive
• Approach
• A new design of cavity hanger to accept
  commercially available pipe.

Existing Scheme
Alternate being worked
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Objective for this new proposal

• While at FNAL I had proposed to explore the
  possibility of redesigning alignment block.
• But this idea of splitting Y shaped hanger is
  something new.(Maybe too far fetched.)The
  Objective is
• To be able to use available Extruded seamless SS
  pipes.Saves money and time both.
• Save money by eliminating the machining operation
  of entire welded structure (pipe plus the Y
  shaped hanger of cavities).

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Proposal for a different Supporting scheme

• It is proposed to split the Y shaped hanger in
  two parts.
• The top part can be laser welded to the pipe.
• The bottom part will be put on surface plates
  which are coplanar.
• The bottom parts of hangers will be aligned . and
  clamped on it.

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HANGER,CAVITY LUG
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Split hanger
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Proposal (contd.)

• In the next step the pipe along with upper part
  of Y shaped hanger will be placed above the
  aligned supports.
• The T and C shaped supports will be placed at
  whatever position they get placed, by virtue of
  the irregularities in the pipes shape.
• These T and C shaped parts will be welded with a
  laser in pulse mode so that there is no
  distortion.

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T C Shaped parts
With This step irregular shape of pipe does not
disturb cavity supporting part (i.e. lower part
of hanger).
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Laser welding
Laser welding with Nd-Yag in pulse mode ensures
that no welding distortion takes place at bottom
part of hanger.
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What we want to Achieve

• So what we may achieve is that the cavity axis
  which depends on lower part of hanger is
  unaffected by irregular shape of pipe.
• It further prevents machining of a 12meter long
  structure. Which surely is an arduous task.

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Problems anticipated

• Some changes in the top support plate.
• During contraction the pipe may induce a shift of
  about 100 microns in Y-Y direction,if we assume a
  camber of 20mm.
• This could be offset by giving an initial pre
  defined,calculated offset.

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Case 1 - F. E. analysis (Camber of 20mm in
vertical plane)
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Results
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Case 2 - F. E. analysis (Camber of 20mm in
Horizontal Plane)
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Results
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Please let us know what are the problems in this
concept.
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Update on End Group Machining from single block

• The first Prototype made in copper was presented
  in the last meeting

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Update on End Group (contd.)
The second Prototype made in copper is also
ready. This is made to dimension with all
tolerances. Inspection pending. Contrary to the
quantity projection last time ,it is requested
that at least four solid cylindrical blocks of
Dia.155mm and length 125mm will be needed.
Next Step We are now at a stage where we will
need Niobium material very soon.
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• THANKS