Status ATLAS SCT 2002 n NIKHEF Contributions to

Status ATLAS SCT 2002 n NIKHEF Contributions to ATLAS: n n n Magnets – discussed by Frank Trigger DCS Muon MDT and alignment – Covered by next talk SCT Talk Outline: n n n SCT Progress Past Year NIKHEF SCT Work Past Year Future NIKHEF Work SCT Week 2 Oct 2002 N. P. Hessey NIKHEF 1

ATLAS Detector SCT Week 2 Oct 2002 N. P. Hessey NIKHEF 2

SCT Progress – Barrel n 1 st Carbon Fibre Cylinder Delivered n n Modules n n n 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 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 n n Many modules run simultaneously With good grounding and shielding, no extra noise and good rejection of external noise SCT Week 2 Oct 2002 N. P. Hessey NIKHEF 3

Barrel System Test SCT Week 2 Oct 2002 N. P. Hessey NIKHEF 4

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

Feedback Model (S. Peeters simulation) SCT Week 2 Oct 2002 N. P. Hessey NIKHEF 6

Feedback Reduction with Filter Glued on Chip S-curves Before Filter: After Filter: Filter Circuit glued to ABCD Chip Joop Roverkamp/Henk Peek SCT Week 2 Oct 2002 N. P. Hessey NIKHEF 7

Radiation Hardness of Endcap Modules n June 2002: n Two Endcap Modules Irradiated n n n 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: n n Some chips out of spec on irradiation; most OK/on the edge Are Endcap modules worse than Barrel? (I. e. , is K 5 bad? ) n n Fix: We can raise threshold from 1 f. C to 1. 2 f. C n n Don’t know any mechanism why they should be Hybrid power supply lines all OK after irradiation Could be statistics? Barrel were lucky? Fixes noise rate; little effect on efficiency or tracking Raise bias to 450 or 500 V: n Regains full charge collectione efficiency; Modules hold this HV SCT Week 2 Oct 2002 N. P. Hessey NIKHEF 8

NIKHEF SCT Progress Module Noise Model – Simon Peeters n n 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: n n Modules are 10 -20 % noisier than predicted Best quality chips are closer to prediction Chip-0 Output Noise: Conclusion: we have a good hybrid, close to ideal But…still some things not understood, e. g. anti-noise at low signals SCT Week 2 Oct 2002 N. P. Hessey NIKHEF 9

Module Manufacture – 5 Inner K 5 Modules Made n n n Aim was to test K 5 and develop assembly techniques and QA All are in specs; most important parameter within ~1 micron Sent to test centres n n n 3 to system test 1 for thermal tests 1 for irradiation SCT Week 2 Oct 2002 N. P. Hessey NIKHEF 10

Discs n n Order placed with PCI in July 2002 n First 2 Discs Delivered Last Week n DU 01: In Spec n DU 02: Not flat enough n Needs work with PCI to see what can be done Cylinder and Wings contract imminent n n NIKHEF Cylinder due July 2003 Cheap-O Prototype n n Torlon Inserts Succesful n ~300 per disc; low X 0 Now glued to disc Next: machine flat Send to UK for Services tests SCT Week 2 Oct 2002 Flatness of DU 01, side 1: ~0. 4 mm N. P. Hessey NIKHEF 11

Cheap-O – with inserts, ready for measurement SCT Week 2 Oct 2002 N. P. Hessey NIKHEF 12

Tooling to machine discs flat n Discs ~0. 5 mm flat; Modules need better: n n For placement; For Services Clearances We machine inserts to 0. 1 mm flatness SCT Week 2 Oct 2002 n n n Stiff-back rohacell sandwich made Most fittings made Ready Feb 2003 N. P. Hessey NIKHEF 13

Future NIKHEF Work n NIKHEF Site Qualification n n Endcap Module Production n 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 Officially starts April Hybrid delayed though…looks optimistic Discs n n Sort out flatness Finalise disc layout details Test services, inserts etc. ; incorporate minor improvements Start machining discs SCT Week 2 Oct 2002 N. P. Hessey NIKHEF 14

Disc Assmbly n H 026: n Glue inserts n add services SCT Week 2 Oct 2002 N. P. Hessey NIKHEF 15

H 023/24/25 Assembly n n n Module assembly Modules-to-disc Disc-to-Cylinder Testing C 3 F 8 Evaporative Cooling Whole disc readout SCT Week 2 Oct 2002 N. P. Hessey NIKHEF 16

The End – 2005 Ship One Endcap to CERN SCT Week 2 Oct 2002 N. P. Hessey NIKHEF 17