Tracker Subsystem 1

GLAST LAT Project FM6 PSR, July 21, 2005

GLAST LAT TrackerGLAST LAT Tracker

Tower6 Pre-Ship ReviewTower6 Pre-Ship Review

Luca.latronico@pi.infn.it

INFN-Pisa

Tracker Subsystem 2

GLAST LAT Project FM6 PSR, July 21, 2005

Tower 6 - Assembly and test highlightsTower 6 - Assembly and test highlights

• May 26 - June 1, 2005 (INFN-Pisa) : – assembly of complete tray stack

– incomplete cable set (C0,C1,C2,C3,C4) due to late arrival of complete set

– Sidewalls, alignment

• July 1-4, 2005 (INFN-Pisa) : – Completion of flight cable installation

(after sidewalls removal)

– Final CPT and ship to Roma

• July 5, 2005 (Alenia-Roma) : – VIB test

• July 8-15, 2005 (Alenia-Roma) : – TVAC test with tower 7

• July 20, 2005 (Roma)– Through customs in Roma airport

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

Tracker Subsystem 3

GLAST LAT Project FM6 PSR, July 21, 2005

Tower 6 - Assembly and components detailsTower 6 - Assembly and components details

Tower PN: LAT-DS-00722 (rev3)Tower SN: 6

Tracker Subsystem 4

GLAST LAT Project FM6 PSR, July 21, 2005

Tower 6 - ConfigurationTower 6 - Configuration

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 5.3 Nm on TWR 6, spec is (5.08 +0.56/-0 Nm)

• EMI taping TBD at SLAC

Tracker Subsystem 5

GLAST LAT Project FM6 PSR, July 21, 2005

Tower 6 – Alignment, CG & MASSTower 6 – Alignment, CG & MASS

Tower 6 well aligned and inside stayclear

Mass and CG near estimated values (when used real masses)

Full data available from EIDP and INFN-PISA web site

Tracker Subsystem 6

GLAST LAT Project FM6 PSR, July 21, 2005

Tower 6 – Open NCRsTower 6 – Open NCRs

• INFN/PI-507: – 2 holes in the base plate were not threaded (the 5th hole from corner -X +Y on the -X side

and the 3rd hole from the +X-Y corner on the +x side) and therefore the corresponding screws are missing

– TVAC results show no impact on the tower

– the NCR can be closed and converted into a SLAC one for referencethe NCR can be closed and converted into a SLAC one for reference

• INFN/PI-533: Bad channels out of spec– with reference to tray NCRs 528, 529 layers X3, Y3, fail test TE301 as expected and due to

known problems

– The overall number of bad channels is small, and the status of channels was monitored through TVAC test and show no significant loss of channels (see next slide), the NCR can the NCR can be closed and converted into a SLAC one for referencebe closed and converted into a SLAC one for reference.

• INFN/PI-546: Vacuum level out of specification– The situation is similar to earlier TVAC tests and the proposal is to accept the test as for

previous MRBs

Tracker Subsystem 7

GLAST LAT Project FM6 PSR, July 21, 2005TKR Tower 6 Total Bad channels vs time

0

5

10

15

20

25

Nu

mb

er o

f D

isco

nn

ecte

d c

han

nel

s

Y16 Y17 Y15 Y9 X4 Y4 Y3 X3 Level

• ~ 180 bad channels overall (less than 0.35%): ~60% are dead, ~20% disconnected, ~20% noisy• half dead channels are located on layers X3 and Y3 and were known to slightly exceed specification already at

tray level (max 16 bad chans - NCRs 528, 529): trays were accepted to maintain tower assembly schedule• Most dead channels are due to broken coupling capacitors on ladder strips that inject high currents into the

corresponding GTFE amplifiers: the first ladders w/o encapsulation of the 2nd production lot were within specs but had somewhat larger number of broken AC coupling due to non perfect bonding settings, which were corrected immediately afterward. Integration of such ladders exceeded tray specification

Tracker Subsystem 8

GLAST LAT Project FM6 PSR, July 21, 2005

Tower 6 - EfficiencyTower 6 - Efficiency

• all layers with efficiency > 99.3%, X3 with 98.9% due to bad channels • average layer efficiency (pre-ship) at the tower level is 99.7% (required 98%)

0

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40

Layer

Ba

d c

ha

nn

els

97

98

99

100

101

102

Eff

icie

nc

y

DisconnectedMasked (hot/disc)

Hot (not masked)Efficiency (%)100% efficiency

98% requirement

Tower 6 - run 309000994

Tracker Subsystem 9

GLAST LAT Project FM6 PSR, July 21, 2005

Tower 6 TVAC – vacuum out of specTower 6 TVAC – vacuum out of spec

-70

-60

-50

-40

-30

-20

-10

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90

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Date

Tem

per

atu

re (

°C)

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

101 Cold Plate 102 Cold Plate +X

103 Cold Plate +Y 105 Cold Plate -Y

01 TWR7 center top 02 TWR7 top C-O -X

04 TWR7 swall -X n.1 10 TWR7 center bot

12 TWR7 bot C-O +X 32 TWR6 center top Tray

33 TWR6 top c-o -X 37 TWR6 swall -X n.1

40 TWR6 swall +X n.9 43 TWR6 bot c-o +X

Pressurre

Same behaviour as previous tests – proposal is to accept the test:

•Vacuum slightly higher than spec (~> 10-4 vs 5x10-5 Torr) during hot soaks•Vacuum level improving with time•same pressure behaviour in dry run with MGSE