GLAST LAT Tracker Tower-1/3 Pre-Ship Review

1. GLAST LAT Tracker Tower-1/3 Pre-Ship Review INFN-Pisa

2. Tower 1 - Assembly and test highlights • Feb 14-21, 2005 (INFN-Pisa) : • assembly (tray stack, cables, sidewalls, alignment, turn-over) • test (CPT) • Feb 28 - Mar 14, 2005 (Alenia-Roma) : • VIB test • TVAC test: noise anomaly on layer X16 (see NCR INFN/PI-430) • Mar 17-19, 2005 (INFN-Pisa) : • Replacement of tray 17 (M063) • Apr 5-15, 2005 (Alenia-Roma) : • New VIB test • New TVAC test • Apr 19, 2005 (Roma) • Through customs in Roma airport • Full EIDP details at: • http://glast.pi.infn.it (soon available) • Quality Assurance page • EIDP links

3. Tower 1 - Assembly and components details Tower PN: LAT-DS-00722 (rev3) Tower SN: 1

4. Tower 1 - Configuration Configuration: • Kapton tape applied on the flex cables only on termination resistors • Poron foam 0.047 THK used on bottom tray sides +Y and –Y (1 foam layer on cables) • 3 layers of Poron foam 0.047 THK used on Bottom Tray X sides and Top Tray -X (in place of 5 layers of 0.037) • Substitution of tray 063 according procedure in Annex 2 NCR/FM/INFN-PI-430 • See NCR/FM/INFN-PI-430 & NCR/FM/INFN-PI-435 for more details

5. Tower 1 - Alignment data • All measurements within stay-clear and within specification.

6. Tower 1 - Alignment data Bay to Tower Assembly <50 microns offset Center BCS to TCS ≈0 deg rotational offset from BCS to TCS Sidewalls Profile SCS Same shape and dimension Same stayclear margins Difference worst case <50 microns

7. Tower 1 - CG & MASS Conclusions • Tower 1 well aligned and inside stayclear • Test after environmental tests skipped as per MRB 3/24/2005 • Mass and CG near estimated values (when used real masses)

8. Tower 1 – Open NCRs • INFN/PI-424: Noise anomaly on layer Y0, ladder 3. • Appeared once at first TVAC cycle and never showed again. • As per MRB held on March 21, 2005, the NCR can be closed. • INFN/PI-430: Malfunction of layer X16, ladder 0. • Consistently observed in vacuum. • The tray has been replaced and it’s now under investigation. • New VIB and TVAC tests passed successfully. • As per MRB the NCR can be closed. • INFN/PI-459: Vacuum level out of specification. • Common to Tower 3, see following slides. • INFN/PI-461: Communication problem when reading the two towers together. • Common to Tower 3, see following slides.

9. Tower 1 - disconnected channels • ~ 250 disconnected channels overall (less than 0.5%). • Number of disconnected channels basically stable throughout the environmental tests. • The small variation is almost completely due to three layers (related NCRs at the tray level closed): • X17 – some cracks on the pitch adapter, no change at all through TV cycles • Y0, Y3 – most likely it’s a delamination issue

10. Tower 1 - Efficiency Overall efficiency (as measured during the post-TV CPT) at the tower level is 99.6%.

11. Tower 3 - Assembly and test highlights • Mar 15-29, 2005 (INFN-Pisa) : • assembly (tray stack, cables, sidewalls, alignment, turn-over) • test (CPT) • Apr 4-15, 2005 (Alenia-Roma) : • VIB test • TVAC test: • Apr 19, 2005 (Roma) : • Through customs in Roma airport • Full EIDP details at: • http://glast.pi.infn.it (soon available) • Quality Assurance page • EIDP links

12. Tower 3 - Assembly and components details Tower PN: LAT-DS-00722 (rev3) Tower SN: 3

13. Tower 3 - Configuration Configuration: • Kapton tape applied on the flex cables as per Annex to NCR/FM/INFN-PI-435) • Poron foam 0.037 THK used also for bottom tray sides +Y and –Y ( 3 Kapton tape layers + 1 foam 0.037 layer) • 4 layers of Poron foam 0.037 THK used on Bottom Tray –X side (in place of 5 layers)

14. Tower 3 – Open NCRs • INFN/PI-439: Disconnected channels on the bottom tray. • 38 disconnected channels found after the tray assembly • Increased up to 70 after the thermal cycles at the tray level (delamination issue) • Some further fluctuation during the tower environmental test • As per MRB the NCR can be closed. • INFN/PI-452 minor: Little scratch on one of the wafers of LGT 014. • Occurred while connecting cable 6 – J2 connector. • The layer has been continuously monitored during the tower environmental tests • The NCR can be closed. • INFN/PI-473 minor: Wrong positioning of the shock recorder on the ISC. • The shock recorder is rotated by 180 degrees on the x-y plane with respect to its nominal position. • The proposed disposition is close the NCR and use as is. • INFN/PI-459: Vacuum level out of specification. • Common to Tower 1, see following slides. • INFN/PI-461: Communication problem when reading the two towers together. • Common to Tower 1, see following slides.

15. Tower 3 - Alignment data • All measurements within stay-clear and in spec

16. Tower 3 - CG & MASS Conclusions • Tower well aligned and inside stayclear • Test after environmental test skipped as per MRB 3/24/2005 • Mass and CG near estimated values (when used real masses)

17. Tower 3 – Disconnected channels ~ 200 disconnected channels overall (less than 0.5%). Number of disconnected channels basically stable throughout the environmental tests. The overall variation is basically due to the fluctuations in the bottom tray.

18. Tower 3 - Efficiency Overall efficiency (as measured during the post-TV CPT) at the tower level is 99.6%. The only layer out of spec is the bottom tray (see NCR INFN/PI-439)

19. Tower 1 and 3 – Communication problems • Relevant NCR: • INFN/PI-461 • Symptoms: • Impossible to operate the two towers at the same time – except for the simple register tests • Both towers consistently 100% functional when tested one at a time • All the electrical tests foreseen by the procedure performed for the two towers in series • Root cause: • The problem is still under investigation • It is clearly an issue with the EGSE/test setup and NOT an issue with the towers. • Proposed disposition: • Continue the investigation, close the NCR INFN/PI-461 (on Tower 1 and 3) and open a different NCR on the EGSE setup.

20. Tower 1 and 3 – Vacuum level out of spec • Relevant NCR: • INFN/PI-458, INFN/PI-459 • Non conformance: • The vacuum level at the first hot soak was 1.04E-4 torr (specs call for 5E-5), getting better in the following cycles. • Considerations and proposed disposition: • The annex to the two NCRs contains a details analysis of the data collected during the environmental tests (explaining why INFN thinks that the goal of the test has been achieved), as well as suggestions for possible improvements of the test facility. • See http://glast.pi.infn.it/database/scripts/newsrv/NCRAnnex/Annex1_to_NCR_FM_INFN_PI_459.doc • The proposed disposition is use as is.

21. Tower 1 and 3 - Conclusions • Assembly and test highlights: • 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 • First environmental test of a tower (tower 1) after the EMI taping successfully completed • A few NCRs needed the completion of the environmental tests to be closed • Issues: Tower 1 - layer X16 • Noise anomaly detected during the environmental tests. • The tray has been taken apart and replaced • Environmental tests at the tower level have been repeated. Investigation on the problematic tray goes on in parallel • Issues: Communication problems • Clearly due to the test setup, investigation is in progress • All functional tests performed with one tower at a time powered