Far-Forward Engineering Meeting

→ US/Eastern
Description

https://bnl.zoomgov.com/j/1658386942?pwd=jfdBW1OFxwIy2RZtW5c7jcQLg87afY.1

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Meeting topics:

*Roman pots design discussion
    --Impedance calculations (updates, if any)
    --vacuum system design
    --Discussion about integration of readout boards + staves
*Geometry updates
*AOB

 

 
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----> No slides presented today - just a discussion

Attendees: Guna, Charlie, Yulia, Chang, Alex, Karim

---> General note: Meeting will be moved to 10am (BNL time, one hour earlier) on Tuesdays, biweekly. This is to better accommodate participation from Europe.

 

Discussion about engineering workforce

  • Designer support from JLAB on these subsystems mostly gone now. Alex will discuss with Doug Holmes how to organize this going forward.
  • Agreed that we should have some separate support for the B0 and the RP/OMD due to the very different constraints on these detectors.

 

Roman pots/OMD engineering discussion

  • Alex posed the idea of putting the RBv1 (readout board) into the vacuum with the staves to (drastically) reduce the feedthrough requirements for the scattering chambers. It would basically limit the feedthroughs to power, and a bundle of fibers from the readout board.
    • Charlie commented that this is worth pursuing, so Alex will discuss with the electronics people working on the stave design, Tonko on RBv1, and also see about reaching out to HERMES people who worked on a silicon detector which operating in vacuum to see what steps they took to limit outgassing.
    • Some additional questions from Charlie and Alex:
      • What kind of cleaning can be done on the boards prior to installation (e.g. cleaning entire board with Isopropyl to remove impurities)?
      • Do we need special considerations for the bump bonding to ensure debris doesn't get between the sensor and ASIC during cleaning, and to limit outgassing.
      • Vacuum "gradient" between RP chimney and beam, area (actual scattering chamber) - how to maintain the vacuum near the beam if there is more outgassing from components in the chimney, needed pumps, etc.
  • We also need to get some better idea of the time it takes to pump down to required level, even before considering outgassing of materials.

 

Zero-Degree Calorimeter

  • EMCAL is still to large in transverse size - needs to be shrunk to reduce interference with vacuum system, while still preserving physics performance (area could be shrunk by 20-30% without likely impact to actual measurements - needs discussion with detector group).
  • Aim to remove scissor table for the ZDC - adds additional potential risk - looking at platform over the ZDC as an option to access PCBs for minor maintenance. 
    • Addition of gate valves on either side of pipe near ZDC would allow remove small pipe section for larger maintenance. 
  • Need to also accommodate the charge particle veto, which is currently missing from all design drawings --> discussion with ZDC detector folks.

 

B0 detectors

  • B0 meetings are on Thursdays at 8am BNL time (when a meeting is called) -- meeting this week will include discussion on workforce.
  • Need clarification on hadron beam pipe inside the B0 to ensure we have taper dimensions in our simulations.
    • Requires follow-up with Guna.
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