Tracker Subsystem 1

GLAST LAT Project GLAST Collaboration Workshop, Castelfalfi, 9/23/2005

GLAST LAT TrackerGLAST LAT Tracker

Tower 11, 12, 13 Pre-Ship Tower 11, 12, 13 Pre-Ship ReviewReview

Luca.latronico@pi.infn.it

INFN-Pisa

Tracker Subsystem 2

GLAST LAT Project GLAST Collaboration Workshop, Castelfalfi, 9/23/2005

Towers Assembly and test flowchart highlightsTowers Assembly and test flowchart highlights

• July 29 - August 16, 2005 (INFN-Pisa) : – assembly of complete tray stack

– incomplete cable set• tower 11: non-flight C1,C2• tower 12: missing C5• tower 13: missing C2, C5

– Functional and performance tests

– Sidewalls, alignment

• September 1-14, 2005 (Alenia-Roma)– X-Y-Z vibrations

– Thermal-Vacuum cycles

• September 16-21, 2005 (INFN-Pisa) : – Missing cables installation and

replacements

– Solithane, EMI taping

– Alignment verification, final CPT

• Full EIDP details (soon) at: – http://glast.pi.infn.it

Tower 11, 12, 13 finalization + tower 15 assembly made the clean room VERY

crowded this week!

Tracker Subsystem 3

GLAST LAT Project GLAST Collaboration Workshop, Castelfalfi, 9/23/2005

Towers – Delivery configurationsTowers – Delivery configurations

Tracker Subsystem 4

GLAST LAT Project GLAST Collaboration Workshop, Castelfalfi, 9/23/2005

Towers – Delivery configurationsTowers – 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-004C2-008 non-flight installed in place of C2-018

Tower 12: C5 missing

Tower 13: C2 missingC5 missing

Note: 16 cables over 24 came from Pioneer

Tracker Subsystem 5

GLAST LAT Project GLAST Collaboration Workshop, Castelfalfi, 9/23/2005

Towers configuration and mechanical verificationsTowers configuration and mechanical verifications

Alignment, Mass, COG:

• All towers well aligned and inside stayclear

• Masses and CG near estimated values (when used real masses)

• Full data available from EIDP and INFN-PISA web site

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)

Tracker Subsystem 6

GLAST LAT Project GLAST Collaboration Workshop, Castelfalfi, 9/23/2005

Towers 11, 12, 13 – Open NCRsTowers 11, 12, 13 – Open NCRs

• Environmental test in non-flight configuration– 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 closedthe NCR can be closed

• Hot/cold power off/on not performed– 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 closedthe NCR can be closed

• Vacuum level out of specification– 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 closedthe NCR can be closed

• INFN/PI-573(twr11): some screws out of torque on sidewall +X– ~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 closedthe NCR can be closed

Tracker Subsystem 7

GLAST LAT Project GLAST Collaboration Workshop, Castelfalfi, 9/23/2005

TVAC – vacuum level out of specTVAC – 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 8

GLAST LAT Project GLAST Collaboration Workshop, Castelfalfi, 9/23/2005

Towers EfficiencyTowers Efficiency

Tower 11, 12, 13 layers efficiency

0

10

20

30

40

50

60

98 98.2 98.4 98.6 98.8 99 99.2 99.4 99.6 99.8 100

efficiency (%)

specEfficiency – bad channels correlation

ConclusionsConclusions

The clean room is sadly empty and people The clean room is sadly empty and people are looking for things to do (maybe)are looking for things to do (maybe)

butbut

3 excellent towers are on their way to the 3 excellent towers are on their way to the LAT GRID at SLACLAT GRID at SLAC