GLAST LAT Project
GLAST Collaboration Workshop, Castelfalfi, 9/23/2005
GLAST LAT Tracker
Tower 11, 12, 13 Pre-Ship
Review
Luca.latronico@pi.infn.it
INFN-Pisa
Tracker Subsystem
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GLAST LAT Project
GLAST Collaboration Workshop, Castelfalfi, 9/23/2005
Towers Assembly and test flowchart highlights
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July 29 - August 16, 2005 (INFN-Pisa) :
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assembly of complete tray stack
incomplete cable set
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X-Y-Z vibrations
Thermal-Vacuum cycles
September 16-21, 2005 (INFN-Pisa) :
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Functional and performance tests
Sidewalls, alignment
September 1-14, 2005 (Alenia-Roma)
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tower 11: non-flight C1,C2
tower 12: missing C5
tower 13: missing C2, C5
Missing cables installation and
replacements
Solithane, EMI taping
Alignment verification, final CPT
Full EIDP details (soon) at:
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http://glast.pi.infn.it
Tracker Subsystem
Tower 11, 12, 13 finalization + tower 15
assembly made the clean room VERY
crowded this week!
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GLAST LAT Project
GLAST Collaboration Workshop, Castelfalfi, 9/23/2005
Towers – Delivery configurations
Tracker Subsystem
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GLAST LAT Project
GLAST Collaboration Workshop, Castelfalfi, 9/23/2005
Towers – Delivery configurations
Tower PN: LAT-DS-00722 (rev3)
Tower SN: 11, 12, 13
Environmental test performed with following
configuration variations:
Tower 11:
C1-001 non-flight installed in place of C1-P-004
C2-008 non-flight installed in place of C2-018
Tower 12:
C5 missing
Tower 13:
C2 missing
C5 missing
Note: 16 cables over 24 came from Pioneer
Tracker Subsystem
4
GLAST LAT Project
GLAST Collaboration Workshop, Castelfalfi, 9/23/2005
Towers configuration and mechanical verifications
Configuration:
• Kapton tape and foam applied on the flex
cables as per LAT-DS-00722
• 4 layers of Poron foam 0.037 THK used on
Bottom and Top Tray (–X) side (in place of 5
layers)
• Base Plate assembly:
•Torque of nuts 5.4 Nm, spec is (5.08 +0.56/-0
Nm)
Alignment, Mass, COG:
Tracker Subsystem
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All towers well aligned and inside stayclear
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Masses and CG near estimated values (when
used real masses)
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Full data available from EIDP and INFN-PISA
web site
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GLAST LAT Project
GLAST Collaboration Workshop, Castelfalfi, 9/23/2005
Towers 11, 12, 13 – Open NCRs
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Environmental test in non-flight configuration
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Hot/cold power off/on not performed
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INFN/PI-NCRs: 578 (twr12), 574 (twr13)
The problem is due to a known and documented issue with resetting MCM (NCR 417) with
missing cables
To avoid the many and unknown number of power cycle needed to re-establish a good
configuration with as many readable layers as possible, hot/cold switch on and off were not
performed
SLAC has requested waiver LAT-XR-07340 on this issue relative to towers 7,9,10,12,13
the NCR can be closed
Vacuum level out of specification
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INFN/PI-NCRs: 568 (twr11), 575 (twr12), 569(twr13)
environmental test runs were performed with missing or non-flight cables, as agreed by an MRB
the NCR can be closed
INFN/PI-NCRs: 581 (twr11), 583 (twr12), 582 (twr13)
The situation is similar to earlier TVAC tests and the proposal is to accept the test as for previous
MRBs
the NCR can be closed
INFN/PI-573(twr11): some screws out of torque on sidewall +X
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~20% of the +X sidewall screws found out of torque after Z-axis vibration
All screws were re-torqued to spec, X-Y axis vibrations were performed, all screws torque were
checked and no change was found
the NCR can be closed
Tracker Subsystem
6
GLAST LAT Project
GLAST Collaboration Workshop, Castelfalfi, 9/23/2005
TVAC – vacuum level out of spec
Same behaviour as previous tests – the
proposal is to accept the test:
•Vacuum slightly higher than spec (~>
10-4 vs 5x10-5 Torr) only during hot
soaks
•Vacuum level improving with time
Tracker Subsystem
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GLAST LAT Project
GLAST Collaboration Workshop, Castelfalfi, 9/23/2005
Towers Efficiency
60
T o w e r 1 1 , 1 2 , 1 3 la ye rs e ffic ie n c y
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40
30
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Efficiency – bad channels correlation
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spec
0
98
9 8 .2
Tracker Subsystem
9 8 .4
9 8 .6
9 8 .8
99
9 9 .2
e ffic ie n c y (% )
9 9 .4
9 9 .6
9 9 .8
100
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Conclusions
The clean room is sadly empty and people
are looking for things to do (maybe)
but
3 excellent towers are on their way to the
LAT GRID at SLAC