1. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 1 THE ATLAS SEMICONDUCTOR TRACKER (SCT) A PRESENTATION ON BEHALF OF THE ATLAS SCT COLLABORATION Overview of the ATLAS SCT Module production Engineering assembly and services Macro-assembly Current Status Summary

2. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 2 Overview of the SCT The SCT forms part of the ATLAS Inner Detector. It is constructed using 4088 silicon micro-strip modules arranged as 4 barrels in the central region and 2 x 9 annular wheels in the forward region Inner Detector (ID)

3. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 3 The modules are arranged to provide 4 space points per track -2.5<  < 2.5 Each module measures two coordinates –Detector pitch is 80  m and +-20 mrad stereo

4. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 4 Modules consist of 4 (2) detectors mounted on a baseboard (barrel) or spine (forward) consisting of Thermal Pyrolytic Graphite + AlN and /or Be0 –Ensures good thermal performance The kapton hybrids are mounted on carbon-carbon substrates Modules have 1526 binary readout channels per module Spatial resolutions  r  = 16  m,  z (  R ) = 580  m Barrel ModuleForward Module

5. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 5 Support structures All support structures, cylinders and discs, are produced using a sandwich material constructed with carbon fibre skins and a Korex core in industry Cu/Ni cooling pipes, precision mounts for modules, power tapes, opto-fibre harnesses + DCS and alignment components are added

6. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 6 MODULE PRODUCTION Production of the 4088 modules occurs at several sites worldwide –Barrel modules in Japan, Scandinavia, UK and USA –Forward modules in Australia, Germany, Netherlands, Spain, Switzerland and the UK Modules must satisfy many criteria and tolerances – e.g. –A range of mechanical tolerances, some < 5  m –Module leakage current < 80  A at 350V –Noise per channel < 1500 ENC –Average noise occupancy at 1 fC threshold < 5 x 10 -4 –< 1% bad channels

7. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 7 A forward module assembly station Vertical scale is deviation from nominal in units of tolerance. Horizontal scale is module number.

8. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 8 Bonding and testing Module bondingModule in testing Module metrology

9. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 9 Threshold ScansNoise Occupancy

10. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 10 MODULE YIELDS BARREL MODULES ‘Good’ modules satisfy all specifications ‘Pass’ modules allow for a small % of modules that just fail a metrology specification –e.g. A deviation in the MIDYF parameter up to 8  m is allowed (the tolerance is 5  m) Current yield of Good + Pass modules is 87% –Pass modules comprise 7.5% of the total The main failure categories are –Abnormal leakage current (54%) –Damaged sensors (16%) –Gross mechanical error (metrology out of specification (14%)

11. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 11 FORWARD MODULES ‘Good’ modules satisfy all specifications Current yield of Good modules is 84.3% ~50% of the ‘failures’ are just outside metrology specifications A ‘Pass’ category may be defined as for the barrel –Should improve Yield > 90%

12. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 12 Lessons learned The progression from prototyping components to full production can introduce some problems and cause delays –e.g. Forward hybrid de-lamination problem Do not underestimate the time required to optimise techniques and commission equipment –e.g. Module assembly techniques Take care in defining specifications –Achieving the same quality in multiple sites is not straight forward Expect unexpected production problems and allow for the time required to solve them –Start with a proper contingency to allow for unexpected problems –Rigorous prototyping and QA will minimise unexpected problems

13. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 13 Engineering assembly and services Preparation of barrels Mounting pads and brackets are added to the cylinder Grounding foils are added Services are added –Cu/Ni cooling pipes –low mass tapes, –Fibre harnesses –alignment components –DCS The ‘dog leg’ tapes have the optical ASICs mounted –These are mounted on the hybrids for forward modules

14. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 14 Mounting services on barrels

15. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 15 Preparation of discs Mounting pads and closeouts are glued onto the disc The pads are machined plane Patch panels and grounding foils are added Services are added –Low mass tapes –C-C mounting blocks soldered onto Cu/Ni pipes are mounted with high precision –Optical fibre harnesses, alignment components and DCS

16. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 16 Metrology results for mounting pin positions for disc 9A The measurements are repeatable (to ± 5  m) after thermal cycling The disc is within specifications

17. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 17 Lessons learned Developing new solutions is time consuming –e.g. bending and soldering Cu/Ni pipes and developing C-C cooling blocks Take care with design of kapton components –Design of tracks, attachment of connectors and stiffening where required The end-cap support cylinders when delivered were not up to specification and needed modifications involving delays

18. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 18 Macro-assembly General infrastructure The macro-assembly is performed in clean conditions (typically class 10000) Evaporative cooling plants based on C 3 F 8 and C 4 F 10 are required to cool large numbers of modules Special tooling is required to mount modules –A robot for the barrel –A manual mounting jig for the end-cap Special tooling is required to mount discs into the support Testing must be done at –7C –Requires final power supplies, DCS and DAQ

19. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 19 Mounting modules onto a barrel The barrel modules are mounted from one side and tilted at an angle of 10 o which allows an overlap between adjacent rows –The clearance between adjacent rows is 1 mm –The cooling block is coated with thermal grease –The mounting procedure requires the module to slide into position –A robot is programmed to perform this delicate manoeuvre The ‘dog-leg’ is connected to the module

20. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 20 Which button do I press??

21. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 21 Mounting modules onto discs Thermal grease is applied to the cooling blocks The module is extracted from its frame The frame is removed and the module is lined up with the mounting blocks –Using the x/y/  stages monitored with cameras The module is positioned and attached Lower modules are added first and then tested electronically and thermally at –7C. Upper modules next.

22. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 22 Mounting discs into the support cylinder The disc is extracted from the test frame frame and attached to the tooling to insert it into the cylinder After insertion the services are added to the end-cap which is then moved to the cold room for testing. The cooling pipes, fibres, low mass tapes and DCS are connected and the disc is readout at –7C. It will be possible to readout two discs simultaneously to check for cross talk

23. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 23 CURRENT STATUS MODULE PRODUCTION Barrel ModulesForward Modules

24. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 24 Structures Barrels –All 4 cylinders are delivered –B3 and B6 are having services attached Discs – All Discs have been delivered to NIKHEF –Preparatory work is 59% complete –Disc 9C is ready for module mounting –Discs 8C, 7C and 9A are having services added –Disc 6C has arrived at RAL and 5C and 4C arrive soon End-cap support cylinders and ‘wings’ –One has been received with ‘wings’ but needed modification –The second is completed but awaiting modification

25. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 25 Macro - assembly Barrels –Oxford is awaiting the arrival of barrel 3 to commence module mounting –Assembly of last barrel is due to be completed in Spring 2005 Discs – Module mounting on Disc 9C is now due to start End-cap support cylinders and ‘wings’ –Expect to mount Disc 9C in end-cap C in July –End-cap C to be ready to ship to CERN in mid-Summer 2005 –End-cap A to be ready to ship to CERN in late 2005

26. Neil Jackson University of Liverpool Hiroshima Symposium 14-17 June 2004 26 SUMMARY The ATLAS SCT is in full production –Module production is well advanced (13% forward and ~75% barrel completed) –Most of the support structures have been delivered –Population with services is underway –The macro-assembly of completed barrels and discs is beginning Several problems have been solved –No show stoppers The schedule for completion is very tight but the collaboration is making every effort to achieve it.