glast lat tracker tower-4/5 pre-ship review

Tracker Subsystem 1

GLAST LAT Project FM4/5 PSR, May 31, 2005

GLAST LAT TrackerGLAST LAT Tracker

Tower-4/5 Pre-Ship ReviewTower-4/5 Pre-Ship Review

[email protected]

INFN-Pisa

Tracker Subsystem 2


Tower 4 - Assembly and test highlightsTower 4 - Assembly and test highlights

• Apr. 13-14, 2005 (INFN-Pisa) : – assembly of complete tray stack– incomplete cable set (C0,C1,C3,C5,C7) due to late

arrival of complete set– CPT could not be performed w/o cables C2, C4,

C6 due to a known issue with GTFE reset (see NCR/INFN/PI-417)

• Apr. 18-21, 2005 (INFN-Pisa) : – Installation of late cables– Tray01 (L020) damaged during cable assembly -

L023 installed in place of L020 (NCR/INFN/PI-470)– CPT– Sidewalls and alignment– Final CPT and ship to Roma

• Apr. 27, 2005 (Alenia-Roma) : – VIB test

• May. 23-27, 2005 (Alenia-Roma) : – TVAC test with tower 5

• May 30, 2005 (Roma)– Through customs in Roma airport

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

Tracker Subsystem 3


Tower 4 - Assembly and components detailsTower 4 - Assembly and components details

Tower PN: LAT-DS-00722 (rev3)Tower SN: 4

Tracker Subsystem 4


Tower 4 & 5 - ConfigurationTower 4 & 5 - 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 5.1 Nm on TWR 4

•Torque of nuts 5.3 Nm on TWR 5, spec is (5.08 +0.56/-0 Nm) higher resonance frequency detected at VIBE test

Tracker Subsystem 5


Tower 4 & 5 – Alignment, CG & MASSTower 4 & 5 – Alignment, CG & MASS

Tower 4 and 5 well aligned and inside stayclear

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

Data available on INFN-PISA web site

Tracker Subsystem 6


Tower 4 – Open NCRsTower 4 – Open NCRs

• INFN/PI-494: Bad channels out of spec– with reference to tray NCRs 460,465,464, 463 (all closed as per MRB) layers X6, Y5, Y3,

Y13 fail test TE301 as expected and due to known problems

– Status of channels was monitored through TVAC test and show no significant loss of channels (see next slide), the NCR can be closed and converted into a SLAC one for the NCR can be closed and converted into a SLAC one for referencereference.

• INFN/PI-496: Vacuum level out of specification.– Common to Tower 5, see following slides.

• INFN/PI-503: CPT reduction after TVAC– Common to Tower 5, see following slides

Tracker Subsystem 7


TKR Tower 4 Disconnected channels vs time

010

2030

4050

60

X6 Y3 Y5

~ 130 disconnected channels overall (less than 0.25%).

Layer X6 is stable as bad channels are due to broken PA traces

Fluctuations in layers Y3 (H17-back-MCM 1117) and Y5 (H16-back-MCM 1049) are due to delaminations in the MCM encapsulant – such MCMs were out of spec (>20 bad chans) already at SLAC and their use was authorized by an MRB for schedule reasons

Tracker Subsystem 8


Tower 4 - EfficiencyTower 4 - Efficiency

• 3 layers with efficiency < 99% as a consequence of missing channels (see previous slide) • overall efficiency (pre-ship) at the tower level is 99.7% (required 98%)

Tracker Subsystem 9


Tower 5 - Assembly and test highlightsTower 5 - Assembly and test highlights

• May 5-9, 2005 (INFN-Pisa) : – assembly (tray stack, cables,

sidewalls, alignment, turn-over)

– test (CPT)

• May. 23-27, 2005 (Alenia-Roma) : – TVAC test with tower 4

– VIB test

• May 30, 2005 (Roma) :– Through customs in Roma airport

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

Tracker Subsystem 10


Tower 5 - Assembly and components detailsTower 5 - Assembly and components details

Tower PN: LAT-DS-00722 (rev3)Tower SN: 5



Tower 5 – Open NCRsTower 5 – Open NCRs

• INFN/PI-492: Bad channels out of spec– 18 bad channels found in Pisa on X2 (9 dead, 9 disconnected)

• 7 dead were known from ladders• nb of dead channels was stably 7 during TVAC; a fluctuation in the Pisa measurement determined the

9 dead channels initially recorded

– Status of channels was monitored through TVAC test and show no loss of channels (see next slide), the NCR can be closedthe NCR can be closed.

• INFN/PI-496: Vacuum level out of specification.– Common to Tower 4, see following slides.

• INFN/PI-504: CPT reduction after TVAC– Common to Tower 5, see following slides



TKR Tower 5 Disconnected channels vs time

0

2

4

6

8

10

12

14

16

18

20N

um

ber

of

Dis

co

nn

ecte

d c

han

nels

X17 X16 X15 Y13 X10 X9 Y7 Y5 X4 X2 Level Y0 X12

• ~ 45 disconnected channels overall (~0.08%).• All layers within specs, i.e. nb of bad chans <16, and stable

• new MCM encapsulant deposition, new MCM-PA gluing fixture, new shipping box are working!



Tower 5 - EfficiencyTower 5 - Efficiency

• worst layer is 99.4%

• overall efficiency (pre-ship) is 99.7%



EGSE/TVAC – Communication problems with 2 towersEGSE/TVAC – Communication problems with 2 towers

• Relevant NCR:– INFN/PI-474

• Problem:– Some instabilities in the EGSE systems for TVAC made it impossible to operate towers 1 and 3

during TVAC test, and the EGSE systems had to be operated independently

• Action taken (as per dispositions):

– TVAC chamber setup was improved by using separate feed-through for EGSE-power lines and chamber temperature control

– GASU cables connecting to the TEMs were shielded

• Findings

– TVAC test of towers 4 and 5 was run with 2 systems in parallel, the NCR can be closedthe NCR can be closed



Tower 4 and 5 – Vacuum level out of specTower 4 and 5 – Vacuum level out of spec

• Relevant NCR:– INFN/PI-458, INFN/PI-459

• Description:– The vacuum level was mostly

outspec during the test (specs call for 5E-5 torr)

• Observations (see annex for details):

– P ~ 3.15E-5 torr at room T after 90 hours of pumping

– correlation between T-P– no improvement after hot soak

as observed with towers 1 and 3– new material (MLI) that did not

undergo bake-out was introduced for thermal blanket of tower 4 and EGSE RF shield

– The proposed disposition is use as is.

-70

-60

-50

-40

-30

-20

-10

0

10

20

30

40

50

60

70

80

90

20/0

5/20

05 0

0.00

.00

20/0

5/20

05 1

2.00

.00

21/0

5/20

05 0

0.00

.00

21/0

5/20

05 1

2.00

.00

22/0

5/20

05 0

0.00

.00

22/0

5/20

05 1

2.00

.00

23/0

5/20

05 0

0.00

.00

23/0

5/20

05 1

2.00

.00

24/0

5/20

05 0

0.00

.00

24/0

5/20

05 1

2.00

.00

25/0

5/20

05 0

0.00

.00

25/0

5/20

05 1

2.00

.00

26/0

5/20

05 0

0.00

.00

26/0

5/20

05 1

2.00

.00

Date

Tem

per

atu

re (

°C)

1

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

Pre

ssu

re (

To

rr)

1

101 Cold Plate 102 Cold Plate +X 103 Cold Plate +Y 104 Cold Plate -X 105 Cold Plate -Y 01 TWR5 center top 02 TWR5 top C-O -X 04 TWR5 swall -X n.110 TWR5 center bot 12 TWR5 bot C-O +X 32 TWR4 center top Tray 33 TWR4 top c-o -X 35 TWR4 swall -X n.1 40 TWR4 swall +X n.9 43 TWR4 bot c-o +X Pressure



CPT reduction for TVACCPT reduction for TVAC

• Reference NCR– 503 and 504

• Description– TE101 (leakage current and power consumption test) not performed after towers 4

and 5 TVAC test

• Proposed dispositions– only perform test TE101 after TVAC is anomalies are detected in the tower CPT

suite • Rationale: correct behaviour of tower during and after TVAC is assessed by

observations of layers noise, channels status, CR detection efficiency

– reduce CR data taking time to 100k events for CPT and 50K for LPT• Rationale: such statistics are enough for efficiency measurements and the test time

reduction allow compressing TVAC in 3 days

– Submit a document change request with the above changes



Tower 4 and 5 - ConclusionsTower 4 and 5 - Conclusions

– Both towers well aligned and within stayclear

– The overall number of disconnected channels is very low

– All the silicon layers (but the bottom tray of tower 3) close to 100% efficiency

– Communication issue during TVAC solved

– Vacuum level still outspec during TVAC

glast lat tracker tower-4/5 pre-ship review

Documents