Difficulties with current

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Difficulties with current mechanical design

• recent FEA results to obtain sufficient
  stiffness of center frame,
• a rather complex structure needs to be used
• ? reduced space and accessibility
• MAFIA WF suppressors on sides of the two
  detector boxes
• are needed
• ? not easy to find a solution with current
• design because center frame is in the way
• and because of the fact that the two boxes
• are mounted separately into the tank
• Dynamic vacuum we must have the option to
  insert a Titanium
• evaporator
• ? not easy with current design
• must enter from the front of tank and, again,
• center frame is in the way
• ? we propose a new design

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New tank frame design summary

• Plus points
• center frame much stiffer
• optimally positioned short legs,
• no more problems of bending
• not any longer in our way (more accessibility
  to critical
• items of VD, see below)
• all referencing is achieved with a much
  simpler design
• alignment and reproducibility
• VD easier to mount and position in the tank
• build in complete VD at once
• solves accessibility problem on one side of
  the beam pipe
• no more need of tilting mechanism during VD
  installation
• easier access to the critical WF suppressor
• more accessibility for connection to exit foil

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New tank frame design summary (continued)

• Minus points
• re-do FEA calculations
• two detector boxes are not interchangeable any
  longer
• (but individual stations can be)
• all feedthroughs on the same big flange
• all cables and repeater cards on same side
• present choice of feedthrough limits total
  number of pins
• to about 25000 !!

Conclusion We like the new design.
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NIKHEF VD responsibilities how do we currently
see it ? YES, ours NO, not ours (not
included here Pile-up and FEE)

• Cabling in vacuum
• provide FEE cabling from feedthroughs to some
  available
• connectors coming from the hybrids
• cabling for cooling system and control (see
  definition below)
• cabling for temperature control of stations
• we assume some group will take care of testing
  the complete
• electrical chain
• Alignment
• provide reference points for station alignment
  with respect to
• center frame
• provide reference points for external alignment
  of boxes
• guarantee internal alignment and reproducibility
  of boxes
• provide possibility to move the center frame via
  a remote-
• controllable XY-table
• interactive alignment with respect to beams
  using tracking,
• beam feedback control and XY-table
• internal alignment and reproducibility of
  detector stations
• we assume some group will take care of the
  complete LHCb

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NIKHEF VD responsibilities how do we currently
see it ? (continued) YES, ours NO, not
ours

• Cooling system and temperature control
• provide a complete cooling system heat
  exchanger (pipes)
• with sufficient cooling power at a fixed and
  stable temperature
• control and monitor of this cooling system
  (hardware and
• software)
• cooling, temperature control and monitor of the
  stations
• (though, we wish to be involved in this)
• VD vacuum (tank and detector boxes)
• provide important part of the vacuum system
  (chambers,
• flanges, feedthroughs), but
• we assume we do not have to provide the exit
  foil (CERN)
• we see the pumps, gauges, quadrupole mass
  analyzers, and
• LHC/VD interface valves as part of the
  infrastructure
• control and monitor of VD vacuum system
  (hardware and
• software).
• Note this has to be integrated with LHC
  control system!

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Timeline and Milestones (highlights)
strong impact on LEMIC (my
personal impression)
End April fix foil geometry and thickness

• manufacture and test self-
• opening valves
• design a Ti evaporator
• build and test cooling system

Early May formal approval by LHCb/VELO of VD
design

• manufacture prototype Al box,
• then leak pressure tests
• manufacture a WF suppressor
• model, perform RF studies

Mid May formal approval by LHCb of VD design

• build and test Ti evaporator
• complete testing (vacuum,
• RF, motion mechanics,
• cooling, etc.)

End June formal approval by LHC of VD design
(LEMIC?)

• start producing manufacturing
• drawings
• build control and monitoring
• systems
• etc.

End December draft TDR
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Some questions, en vrac
Partial bake out of Al box to clean surfaces on
the beam side could we consider baking the box
(e.g. at 80-100 ºC) while cooling the stations
? what are the sensitive components in the Si
stations ? Temperature cycling of Si
stations What will happen to the Si stations ?
Beneficial ? Deteriorating ? (we assume its no
problem) // commented out... // Water
condensation on (cooled) stations // No problems
? (Si, FEE, bonding, etc.) // Vapour pressure at
-30 ºC is 10-1 mbar ? only monolayer. Radiation
resistance of carbon-fiber support
structures how good ? Vacuum design In case
one detector half must be turned off, do we want
to have the possibility to operate the other
half ? Cabling How many wires in total ? What
kind ? cable properties impedance, attenuation,
etc. (what for ? signal, power, control,
digital/analog, etc.) How will the grouping be
done ?