Tracker Subsystem1 GLAST LAT Project FM-B PSR, 10 Feb, 2005 GLAST LAT Tracker Tower-B Pre-Ship Review Luca Latronico INFN-Pisa

Tracker Subsystem2 GLAST LAT Project FM-B PSR, 10 Feb, 2005 Tower B Assembly and test highlights 1/3-1/ (INFN-Pisa) : –assembly (tray stack, cables, sidewalls, alignment, turn-over) –test (CPT) 1/17-2/ (Alenia-Roma) : –VIB test (1/17-18) –New TVAC chamber setup (see NCR/FM/INFN/PI-379) –TVAC test (1/29-2/5) 2/ (INFN-Pisa) : –Alignment verification 2/ : –Through customs in Roma airport Full EIDP details at: – –Quality Assurance page –EIDP links

Tracker Subsystem3 GLAST LAT Project FM-B PSR, 10 Feb, 2005 Tower Alignment data Before Vibe Test After Vibe Test All measurements within stay-clear and in spec before and after ENV tests

Tracker Subsystem4 GLAST LAT Project FM-B PSR, 10 Feb, 2005 TOWER CG & MASS Conclusions Tower well aligned and inside stayclear Stable after Env. Test Mass and CG near estimated values (when used real masses)

Tracker Subsystem5 GLAST LAT Project FM-B PSR, 10 Feb, 2005 Assembly and components details Relevant issues and related NCRs: –INFN/PI-220 (tray Bottom 006) M4X6 instead of M4x8 Proposed disposition is use as is and close –INFN/PI-362 (Tower B) Critical insulation of termination resistor on cable 7 SLAC will provide all cables with Kapton to protect resistors Proposed disposition is use as is and close –INFN/PI-371 (Tower B) Critical insulation between tower cables and fixing clips Kapton tape was used Proposed dispositions are –SLAC will provide all cables with kapton on all termination resistors –use as is and close –INFN/PI-349 (tray heavy 037) GTFE21 back side instabilities Found to be due to bad termination resistor (100Ohm) on test cable Proposed disposition is use as is and close –INFN/PI-383 (Tower B) Complete CPT not performed Proposed dispositions are – use as is and close –Consider removing test from flow-chart and rely on final test after TVAC

Tracker Subsystem6 GLAST LAT Project FM-B PSR, 10 Feb, 2005 Environmental tests highlights VIB test –No new channel loss –No change in alignment TVAC test –New chamber setup –Vacuum level slightly below spec (NCR-379-closed) –Charge to Alenia to investigate chamber capabilities

Tracker Subsystem7 GLAST LAT Project FM-B PSR, 10 Feb, 2005 total disconnected channels < 0.25% ~50% of disconnected channels in 2 layers (Y12, X7): – X7 with large oscillations vs temperature – Y12 responsible for overall channel loss – all other layers were very stable

Tracker Subsystem8 GLAST LAT Project FM-B PSR, 10 Feb, 2005 Semi-disconnected channels (broken ladder wire-bonds) 1 layer only (X5 – tray H037-Front) ~60 bad channels which stabilized during tray thermal cycle and tower assembly no further degradation during tower ENV tests see NCR-368

Tracker Subsystem9 GLAST LAT Project FM-B PSR, 10 Feb, 2005 Open NCRs related to disconnected/bad channels Bad channels NCRs - proposed disposition is use as is and close : –INFN/PI-368 (tray Heavy 037) Last disposition (MRB 1/12/2005) is use as is for tower B; build ladders with no encapsulation and test on tower 1 Disconnected channels NCRs – proposed disposition is use as is and close: –INFN/PI-350 (tray MID 051) 2 more channels lost in TVAC –INFN/PI-346 (tray MID 043) 24 more channels lost in tray thermal cycle and tower TVAC –INFN/PI-384 (tray MID 023) Large fluctuation in number of disconnect vs temperature –INFN/PI-389 (tray Heavy 018) 13 disconnected and 4 noisy found during TVAC test

Tracker Subsystem10 GLAST LAT Project FM-B PSR, 10 Feb, 2005 Conclusions Tower B was assembled, tested and shipped to SLAC in 2 weeks (2 more weeks were lost for the setup of the new Alenia TVAC chamber) No major issue were found in assembly, environmental tests, performance verification – a number of minor issues must be addressed before tower1 activities The overall number of bad channels is very low –New MCMs with no PA disconnection will reduce even more this number and its stability with time/temperature –New heavy and bottom ladders with no wire-bond encapsulation will show their reliability soon (tower1 trays data available next Monday right before assembly)