Pixel/IBL status and plans A.Rozanov A.Rozanov ATLAS-France

Pixel-nSQP Origin of 5% dead modules: ~40% opto- boards(new accessible location), ~40% defects in SQP (mainly soldering) and only ~20% pixel modules (mainly HV). Very good news: Potentially we can bring down dead modules to 1% Bad news: origin of SQP soldering failures is slightly too small opening in solder mask. It is the same in nSQP, so we can expect some mortality from thermal cycles. My guess: 0.4%/year A.Rozanov ATLAS-France

Pixel-nSQP Desinstallation and transport to SR1 done without damages IST introduced into pixels without damages nSQP installation going well, last nSQP 7/8 installed week 7-11 october should be ready to install pixels into ATLAS in January 2014 A.Rozanov ATLAS-France

IBL progress All bare staves delivered All Bare modules produced at IZM: no more bump-bonding merging and disconnections Flex modules production finished 12 out of 14 production staves produced Beam pipe arrived to SR1 essentially ready Ti tube brazing validated in SR1. Stave 0A with 7m length ready for trial installation IBL stave mounting tool ready to start mounting staves: trial mounting will start soon A.Rozanov ATLAS-France

Recent problems AXON connectors break pins (bad design of key) and delays in cable production Accident with humid air penetration into test box in SR1 during CO2 cold tests: staves #7 and #8 destroyed by frost Corrosion on Al wire bonds on 11 staves: further production stopped for investigation A.Rozanov ATLAS-France

AXON connector problem Small serie production used machining instead of moulage. Design was done in a way not compatible with machining tolerances Big rotation freedom: pins are broken during installation Redesign and improve machining tolerances: rotation freedom reduced Cable production can be restarted. A.Rozanov ATLAS-France

Accident with staves 07 and 08 No automatic interlock on humid air Accidental penetration of humid air on cooled staves: frost destroy wire-bonds Repair work starts now, but very small chances to repair to the production level quality Will be probably used to practice work Procedures are tightened to avoid same accidents in future Need good humidity interlocks in ATLAS A.Rozanov ATLAS-France

Corrosion problem Cl contamination of the Al wire bonds and pads Probable origin of Cl: degasing from glue used in module production (strange…, should be proven…) or some contamination (soldering flux or similar) H2O contamination during thermal cycling in the climatic chamber (1.6 m3 rely on chamber drying system) A.Rozanov ATLAS-France

Corrosion reaction Al + 3Cl- -> Al(Cl)-4 + 3e- 2 Al(Cl)-4 + 6H2O -> 2 Al(OH)3 + 6H- + 8Cl- Only way to stop: eliminate Cl and H2O A.Rozanov ATLAS-France

Corrosion seen on-line at LBNL DI water produce bubbling on module pads Strong plasma cleaning prevents corrosion Confirmation: Bonn yes, Geneva no Geneva: flex no SMD Flex contamination??? Batch dependent ???? A.Rozanov ATLAS-France

Wire-bond pull test Corrosion on pad: fragile wire bond No corrosion: normal wire strength Rebond on clean region: good strength A.Rozanov ATLAS-France

Plan of action Understanding origins and restart production Repair staves Build more new stave Precaution measures A.Rozanov ATLAS-France

Understanding and restarting Find pollution origin Eliminate origin (change glue or appropriate cleaning) Strict dry air treatments in full chain UniGe restart loading in November A.Rozanov ATLAS-France

Thermal grease FEI4 Sensor Module flex Araldite/UHU Araldite Wing B Rework A stave 14 Stave section - ZoneA and B

Repair staves Remove wing wire bonds (A) and some FE wire bonds (B), remove corrosion traces Clean staves with plasma cleaning Wire bond again all wings, some FE Replace some bad modules Coating of wire bonds for corrosion protection??? Risks ??? Goal to repair >=6 staves out of 12 A.Rozanov ATLAS-France stave Thermal grease

New stave production Goal: >=8 new staves to be produced Cleaning (avoid contamination)+dry air Bare staves (2-ready, 4 increase specs, more need small repairs) DC modules for ~8-9 staves SC modules for ~4-5 staves (+more worse quality) Total: 8(new) + 6 (repaired) =14 staves to be installed April 2014 No time for extensive cold tests A.Rozanov ATLAS-France

Precaution measures So many unknowns and risks, that we should make all possible and reasonable precaution measures FE-I4-B available for two more IBLs CiS DC tiles: available for 8 more staves Start more CiS DC sensor productions ? Restart IZM bare module bonding ? Order more stave and module flexes ? Repair few (3-5) bare staves at IVW Produce ~14 new bare staves at IVW ? Provide more row material (foam, prepreg) ? A.Rozanov ATLAS-France

IN2P3 contributions Requalification of bare staves Urgent repairs of bare staves Design of repair at IVW of bare staves New bare staves qualification Purchasing of carbon foam and prepreg Modules and stave tests FE-I4-B GADC temperature use for module replacement qualification N2 flow and sonar return control interfaced with humidity safety and interlock More ideas to accelerate and secure IBL issues ? A.Rozanov ATLAS-France

Conclusions Unprecedented production problem All forces (manpower, technical, financial, know-how, administrative) of all institutes, ATLAS TC should be mobilized to install IBL in 2014 Repair maximum possible >= 6 staves out of 12 Produce new >=8 staves Take all precautions measures to face risks A.Rozanov ATLAS-France