Tracker Subsystem1 GLAST LAT Project FM6 PSR, July 21, 2005 GLAST LAT Tracker Tower6 Pre-Ship Review INFN-Pisa

Tracker Subsystem2 GLAST LAT Project FM6 PSR, July 21, 2005 Tower 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: –

Tracker Subsystem3 GLAST LAT Project FM6 PSR, July 21, 2005 Tower 6 - Assembly and components details Tower PN: LAT-DS (rev3) Tower SN: 6

Tracker Subsystem4 GLAST LAT Project FM6 PSR, July 21, 2005 Tower 6 - Configuration Configuration: Kapton tape and foam applied on the flex cables as per LAT-DS layers of Poron foam 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 ( /-0 Nm) EMI taping TBD at SLAC

Tracker Subsystem5 GLAST LAT Project FM6 PSR, July 21, 2005 Tower 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 Subsystem6 GLAST LAT Project FM6 PSR, July 21, 2005 Tower 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 reference – the 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 NCR can be closed and converted into a SLAC one for reference –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 be 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 Subsystem7 GLAST LAT Project FM6 PSR, July 21, 2005 ~ 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 2 nd 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 Subsystem8 GLAST LAT Project FM6 PSR, July 21, 2005 Tower 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%)

Tracker Subsystem9 GLAST LAT Project FM6 PSR, July 21, 2005 Tower 6 TVAC – vacuum out of spec Same behaviour as previous tests – proposal is to accept the test: Vacuum slightly higher than spec (~> vs 5x10 -5 Torr) during hot soaks Vacuum level improving with time same pressure behaviour in dry run with MGSE