Status ATLAS SCT 2002

1. Status ATLAS SCT 2002 • NIKHEF Contributions to ATLAS: • Magnets – discussed by Frank • Trigger • DCS • Muon MDT and alignment – Covered by next talk • SCT • Talk Outline: • SCT Progress Past Year • NIKHEF SCT Work Past Year • Future NIKHEF Work N.P. Hessey NIKHEF

2. ATLAS Detector N.P. Hessey NIKHEF

3. SCT Progress – Barrel • 1st Carbon Fibre Cylinder Delivered • Mostly in spec, some difficulties achieving the very high precision machining requirements they had • Ready to start mounting brackets • Some delay because of last minute change in layout for clearances • Modules • UK and Japan sites qualified for production • Nordic Group and USA have made modules but still not perfect • Japan in routine production since summer 2002 and now speeding up • UK started routine production • System Test • Many modules run simultaneously • With good grounding and shielding, no extra noise and good rejection of external noise N.P. Hessey NIKHEF

4. Barrel System Test N.P. Hessey NIKHEF

5. SCT Progress - Endcap • Modules • Hybrids: K4/K5/KB/Filters story • Mid 2001 realised K4 had serious problems • Started program to be sure of solving it • 1. Investigate/understand the problem: difficult with binary (hit-or-miss) readout • At NIKHEF we realised it is a feedback from Digital Power Supply to Analogue side • 2. Fix K4 (NIKHEF) • Filters in digital power supply • Worked well on NIKHEF modules, but could not rescue a Liverpool module • 3. New version: K5 (Freiburg) • 4 layer  6 layer + better AGND plane • Now working well • 4. Fit Barrel Hybrid on Endcap Module: KB (Geneva) • Worked as well as Barrel Modules (still some feedback) • Cooling finally worked well, but more material and ?cost? • Would have been a lot of extra engineering work • Decided early 2002 to go ahead with K5 N.P. Hessey NIKHEF

6. Feedback Model (S. Peeters simulation) N.P. Hessey NIKHEF

7. Feedback Reduction with Filter Glued on Chip S-curves Before Filter: After Filter: Filter Circuit glued to ABCD Chip Joop Roverkamp/Henk Peek N.P. Hessey NIKHEF

8. Radiation Hardness of Endcap Modules • June 2002: • Two Endcap Modules Irradiated • Very noisy, out of spec • Optimists: Maybe they got overcooked? • August 2002: Two more irradiated…behaviour much better, well inside spec • Pessimists: Maybe the August ones were undercooked • The Pessimists were right • Status now: • Some chips out of spec on irradiation; most OK/on the edge • Are Endcap modules worse than Barrel? (I.e., is K5 bad?) • Don’t know any mechanism why they should be • Hybrid power supply lines all OK after irradiation • Could be statistics? Barrel were lucky? • Fix: We can raise threshold from 1 fC to 1.2 fC • Fixes noise rate; little effect on efficiency or tracking • Raise bias to 450 or 500 V: • Regains full charge collectione efficiency; Modules hold this HV N.P. Hessey NIKHEF

9. NIKHEF SCT Progress • In addition to feedback also has calculated the fundamental noise limit • Many significant contributions • Many input parameters, some were unknown and had to be measured • End result: • Modules are 10-20 % noisier than predicted • Best quality chips are closer to prediction • Conclusion: we have a good hybrid, close to ideal • But…still some things not understood, e.g. anti-noise at low signals Module Noise Model – Simon Peeters Chip-0 Output Noise: N.P. Hessey NIKHEF

10. Module Manufacture – 5 Inner K5 Modules Made • Aim was to test K5 and develop assembly techniques and QA • All are in specs; most important parameter within ~1 micron • Sent to test centres • 3 to system test • 1 for thermal tests • 1 for irradiation N.P. Hessey NIKHEF

11. Discs • Order placed with PCI in July 2002 • First 2 Discs Delivered Last Week • DU01: In Spec • DU02: Not flat enough • Needs work with PCI to see what can be done • Cylinder and Wings contract imminent • NIKHEF Cylinder due July 2003 • Cheap-O Prototype • Torlon Inserts Succesful • ~300 per disc; low X0 • Now glued to disc • Next: machine flat • Send to UK for Services tests Flatness of DU01, side 1: ~0.4 mm N.P. Hessey NIKHEF

12. Cheap-O – with inserts, ready for measurement N.P. Hessey NIKHEF

13. Tooling to machine discs flat • Discs ~0.5 mm flat; Modules need better: • For placement; For Services Clearances • We machine inserts to 0.1 mm flatness • Stiff-back rohacell sandwich made • Most fittings made • Ready Feb 2003 N.P. Hessey NIKHEF

14. Future NIKHEF Work • NIKHEF Site Qualification • We make five more modules in Jan/Feb • If all OK, we are ready to receive components and start manufacture • These 5 modules can go into ATLAS • Endcap Module Production • Officially starts April • Hybrid delayed though…looks optimistic • Discs • Sort out flatness • Finalise disc layout details • Test services, inserts etc.; incorporate minor improvements • Start machining discs N.P. Hessey NIKHEF

15. Disc Assmbly • H026: • Glue inserts • add services N.P. Hessey NIKHEF

16. H023/24/25 Assembly • Module assembly • Modules-to-disc • Disc-to-Cylinder • Testing • C3F8 Evaporative Cooling • Whole disc readout N.P. Hessey NIKHEF

17. The End – 2005 Ship One Endcap to CERN N.P. Hessey NIKHEF