TKR Tower Assembly PRR

1
GLAST LAT Tracker Tower-B Pre-Ship Review
Luca Latronico INFN-Pisa luca.latronico_at_pi.infn.i
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2
Tower B Assembly and test highlights

• 1/3-1/11 2005 (INFN-Pisa)
• assembly (tray stack, cables, sidewalls,
  alignment, turn-over)
• test (CPT)
• 1/17-2/5 2005 (Alenia-Roma)
• VIB test (1/17-18)
• New TVAC chamber setup (see NCR/FM/INFN/PI-379)
• TVAC test (1/29-2/5)
• 2/8 2005 (INFN-Pisa)
• Alignment verification
• 2/10 2005
• Through customs in Roma airport
• Full EIDP details at
• http//glast.pi.infn.it
• Quality Assurance page
• EIDP links

3
Tower Alignment data

• All measurements within stay-clear and in spec
  before and after ENV tests

4
TOWER CG MASS

• Conclusions
• Tower well aligned and inside stayclear
• Stable after Env. Test
• Mass and CG near estimated values (when used real
  masses)

5
Assembly and components details

• Relevant issues and related NCRs
• INFN/PI-220 (tray Bottom 006)
• M4X6 instead of M4x8
• Proposed disposition is use as is and close
• INFN/PI-362 (Tower B)
• Critical insulation of termination resistor on
  cable 7
• SLAC will provide all cables with Kapton to
  protect resistors
• Proposed disposition is use as is and close
• INFN/PI-371 (Tower B)
• Critical insulation between tower cables and
  fixing clips
• Kapton tape was used
• Proposed dispositions are
• SLAC will provide all cables with kapton on all
  termination resistors
• use as is and close
• INFN/PI-349 (tray heavy 037)
• GTFE21 back side instabilities
• Found to be due to bad termination resistor
  (100Ohm) on test cable
• Proposed disposition is use as is and close
• INFN/PI-383 (Tower B)

6
Environmental tests highlights

• VIB test
• No new channel loss
• No change in alignment

• TVAC test
• New chamber setup
• Vacuum level slightly below spec (NCR-379-closed)
• Charge to Alenia to investigate chamber
  capabilities

7

• total disconnected channels lt 0.25
• 50 of disconnected channels in 2 layers (Y12,
  X7)
• X7 with large oscillations vs temperature
• Y12 responsible for overall channel loss
• all other layers were very stable

8
Semi-disconnected channels (broken ladder
wire-bonds)

• 1 layer only (X5 tray H037-Front)
• 60 bad channels which stabilized during tray
  thermal cycle and tower assembly
• no further degradation during tower ENV tests
• see NCR-368

9
Open NCRs related to disconnected/bad channels

• Bad channels NCRs - proposed disposition is use
  as is and close
• INFN/PI-368 (tray Heavy 037)
• Last disposition (MRB 1/12/2005) is use as is for
  tower B build ladders with no encapsulation and
  test on tower 1
• Disconnected channels NCRs proposed disposition
  is use as is and close
• INFN/PI-350 (tray MID 051)
• 2 more channels lost in TVAC
• INFN/PI-346 (tray MID 043)
• 24 more channels lost in tray thermal cycle and
  tower TVAC
• INFN/PI-384 (tray MID 023)
• Large fluctuation in number of disconnect vs
  temperature
• INFN/PI-389 (tray Heavy 018)
• 13 disconnected and 4 noisy found during TVAC test

10
Conclusions

• Tower B was assembled, tested and shipped to SLAC
  in 2 weeks (2 more weeks were lost for the setup
  of the new Alenia TVAC chamber)
• No major issue were found in assembly,
  environmental tests, performance verification a
  number of minor issues must be addressed before
  tower1 activities
• The overall number of bad channels is very low
• New MCMs with no PA disconnection will reduce
  even more this number and its stability with
  time/temperature
• New heavy and bottom ladders with no wire-bond
  encapsulation will show their reliability soon
  (tower1 trays data available next Monday right
  before assembly)