BCM Overview

1
BCM Overview

• Placement such that system is sensitive to all
  types of beam accidents. gt 2 independent
  subsystems
• Halo losses inside the Pixel volume
• ie interactions with the Be beampipe section
• Showering from outside the TK volume
• Concerns for interference
• Subsystem 1 One as close as possible to BP
• Target same radius as the inner layer of the
  pixel barrel
• Target 8mm from beampipe at final position
• With no FPix squeeze dist 14 mm
• With FPix squeeze dist 23mm
• Subsystem 2 At larger radius
• Not at risk of interfence with BP or FPix
• Support services
• Placement of frontend electronics and services
  must be adjusted once rail system agreed upon (
  BCM treats this issue as secondary, although
  limited space between BCM rail and FPix service
  tube feet)
• Beam Pipe support wires
• Must respect envelop around wires. At present the
  BP group is requesting an envelop of R 15mm

2
Concerns

• Lateral movement of FPix service cylinder toward
  beampipe cuts off space for BCM insertion
• Cabling FPix should done with FPix in final
  position and before beampipe hook up
• BCM and FPix should be independent system
• There should not be any holes in coverage of the
  FPix

3
The problem BCM and FPix envelopes overlap at
rear (z2.6m) of FPix service tube
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Possible solution Very difficult
Kinked BCM rail, straight rail after kink
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(No Transcript)
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D 166mm
d2.5mm
Question of gaps in coverage
Rotating hinged on the front foot outer edge
move 2.5 mm
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Full Squeeze
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10mm Squeeze 1st Layer
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10mm Squeeze 2nd layer
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10mm Squeeze 3rd Layer
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Notes from Kurt

• The reason for the final rotation of the disk
  structure was of course to get the disk plane
  perpendicular to the beam.
• The advantage was also that from the rear face of
  the barrel service tube to the rear face of the
  disk cylinder there was some lateral room which
  facilitates the sorting of cables/pipes going to
  the patch panel PP0.
• No (or only partial) final rotation would on the
  other hand facilitate the mounting of the
  horizontal beam pipe suspension.
• No (or only partial) final rotation will of
  course complicate a lot the software describing
  the geometry (track reconstruction from hits,
  alignment....). Also one should check whether
  there is still overlap of the two half-disks of
  the most remote disk.
• My first guess is that it should be possible to
  omit the final rotation.
• It would imply a correction of the lengths of
  cables/pipes from the disk structure's end flange
  to PP0 which have been determined so far
  assuming full rotation.
• For a more educated guess, I should have a layout
  of the rear face of the disk cylinders as it is
  foreseen now, in particular the arrangement of
  cables/pipes exiting the rear end flange of the
  disk structure.

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From Bruno
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Comments on the FWD pixel track

1. transversal movement in the rail slot of 35 mm,
   hinged on front foot with a lever arm of 2209mm