Tracker Subsystem1 GLAST LAT Project FM8/14 PSR, Oct. 5, 2005 GLAST LAT Tracker Towers 8/14 Pre-Ship Review INFN-Pisa

Tracker Subsystem2 GLAST LAT Project FM8/14 PSR, Oct. 5, 2005 Tower 8 - Assembly and test highlights July 5-18, 2005 (INFN-Pisa) : –assembly of complete tray stack –incomplete cable set (C3,C5 missing, C6 NF) –Sidewalls, alignment July 24 – August 5, 2005 (Alenia-Roma) : –TVAC (7/25-7/28), VIB (8/3-8/4) test RUN I NCR 551 layerX6 noise anomaly August 10 – September 8 (INFN-Pisa) –Stored in shipping container September 9-10, 2005 (INFN-Pisa) : –Tray 7 replacement –C3, C5 installation –C6 NF replacement –Solithane –EMI shield only on top tray for schedule reasons  shield on edges must be done at SLAC –Alignment verification, final CPT September 15-29, 2005 (Alenia-Roma) –VIB (9/15) RUN II (Z axis only) –TVAC (9/26-29) RUN II Full EIDP details (soon) at: –

Tracker Subsystem3 GLAST LAT Project FM8/14 PSR, Oct. 5, 2005 Tower 8 – Environmental test and delivery configurations Tower PN: LAT-DS (rev3) - Tower SN: 8 - Details on NCR 540

Tracker Subsystem4 GLAST LAT Project FM8/14 PSR, Oct. 5, 2005 Tower 8 – Configuration and mechanical verifications Alignment, Mass, COG: Tower 8 well aligned and inside stayclear Mass (32.930Kg) and CG near estimated values (when used real masses) Full data available from EIDP and INFN-PISA web site 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, spec is ( /-0 Nm)

Tracker Subsystem5 GLAST LAT Project FM8/14 PSR, Oct. 5, 2005 Tower 8 – Open NCRs INFN/PI-540: environmental test in non-flight configuration –environmental test run I performed with missing cables C3, C5 and non-flight C6, as agreed by an MRB –Tower 8 sent back to Pisa for flight cable set installation and tray7 replacement (see NCR551) –the NCR can be closed INFN/PI-551: layer X6 noise anomaly (TVAC RUN I) –As per MRB decision, tray 7 (MID007) was replaced with a new tray (MID232), and tower8 retested successfully –the NCR can be closed INFN/PI-561: hot/cold power off/on not performed (TVAC RUN I) –This is an known issue related to testing a tower in a non-flight configuration. –A second TVAC run was performed with a full set of flight cables and such test were performed –the NCR can be closed INFN/PI-587: Vacuum level out of specification (TVAC RUN I) –The situation is similar to earlier TVAC tests and the proposal is to accept the test as for previous MRBs –the NCR can be closed INFN/PI-591: temporary isolated noise glitch on X3 –Referring to NCR 592

Tracker Subsystem6 GLAST LAT Project FM8/14 PSR, Oct. 5, 2005 NCR 551: X6 fixed after tray M007 replacement – now in spec NCR 592 – X3 - see following slide Tower 8 – Bad channels

Tracker Subsystem7 GLAST LAT Project FM8/14 PSR, Oct. 5, 2005 NCR 592 Tracker towers A, 1, 4, 7, 8, 11 showed temporary, isolated noise glitches located on one or few ladders during TVAC test. Figure 1 shows an example of such glitch measured during TE302 test (noise occupancy test on tower 8, layer X3). Such glitches are not systematic, they appeared rarely and immediately disappeared after they are detected; the glitches typically happen at hot soaks (45/50C) or during temperature ramp-down at ~30C, when the tower temperature is not uniform (typical maximum temperature difference across the tower is 20C). Such increase are therefore considered a glitch in the system noise or a pickup, and do not represent an anomaly in the behaviour of the tracker towers. The NCR is raised for documentation purposes.

Tracker Subsystem8 GLAST LAT Project FM8/14 PSR, Oct. 5, 2005 Tower 8 - Efficiency All layers well within spec (eff > 98%), with fluctuations correlated to bad channels no changes in bad channels during RUN II env test Bad channels on new tray7 are within spec, (10 on X7 [1 disconnected, 5 dead, 4 noisy], 9 on X6 [7 dead, 2 noisy]), so we don’t expect surprises - a new efficiency analysis including this new tray will be provided along with full EIDP taken in Alenia after 2 nd TVACTVAC RUN I data

Tracker Subsystem9 GLAST LAT Project FM8/14 PSR, Oct. 5, 2005 Tower 8 TVAC – vacuum out of spec RUN II 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

Tracker Subsystem10 GLAST LAT Project FM8/14 PSR, Oct. 5, 2005 Tower 14 - Assembly and test highlights August 19-26, 2005 (INFN-Pisa) : –assembly of complete tray stack –Complete flight cable set –Solithane, sidewalls, alignment September 1-15, 2005 (Alenia-Roma) : –VIB (9/1-5) –TVAC (9/12-15) NCR 572 for layer Y0 malfunction September 21-30, 2005 (INFN-Pisa) : –Bottom tray replacement –EMI shield only on top tray for schedule reasons  shield on edges must be done at SLAC –Alignment verification, final CPT October 3, 2005 (Alenia-Roma) : –Z-axis new VIB test (9/1-5) Full EIDP details (soon) at: –

Tracker Subsystem11 GLAST LAT Project FM8/14 PSR, Oct. 5, 2005 Tower 14 – Configuration and mechanical verifications Alignment, Mass, COG: Tower 9 well aligned and inside stayclear Mass (33.030Kg) and CG near estimated values (when used real masses) Full data available from EIDP and INFN-PISA web site 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 5.4 Nm, spec is ( /-0 Nm)

Tracker Subsystem12 GLAST LAT Project FM8/14 PSR, Oct. 5, 2005 Tower 14 – Open NCRs INFN/PI-572: layer Y0 malfunction –Failure is compatible with a HV short on ladder 3 produced by some si-strips wire bonds in contact with the wafer edge –As agreed on 9/27 MRB (see annex 4 for details), the following actions were taken: bottom tray B024 was qualified adding a vacuum test in Roma2 (room T, maximum achievable vacuum) and a thermal cycle test (standard range and duration) to standard tray tests – all such tests were run with tray readout always on and passed successfully without showing any anomaly bottom tray B018 was removed from tower 14; inspection of the tray shows a non-perfect adhesion of the MCM to the tray closeout on one edge that causes the short B018 was replaced with bottom tray B024 a Z-axis vibrational test on the reworked tower 14 was performed and passed successfully INFN/PI-588: Post-VIB CPT not performed –Due to unavailability of test equipment at Alenia, tower14 was not retested after the second vib test on z-axis –SLAC will have to perform the test upon arrival –NCR 572 and 588 can be closed when CPT results from SLAC are known –The proposal is to consider Tower 14 flight even if only a z-axis vib test was performed after bottom tray replacement. This is based on the additional test performed on tray B024that rule out any failure like the one detected on B010 the demonstrated capability of the tracker team to perform a successful tray replacement INFN/PI-584: 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. As usual the pressure is slightly out of spec during hot soaks and it gets better with time, being in spec at the 4 th and last soak –the NCR can be closed

Tracker Subsystem13 GLAST LAT Project FM8/14 PSR, Oct. 5, 2005 Tower 14 - Efficiency All layers well within spec (eff > 98%), with fluctuations correlated to bad channels no changes in bad channels during environmental test INFN/PI RUN priori to Env-test