The ATLAS SCT

1. The ATLAS SCT Ulrich Parzefall Universität Freiburg

2. SCT-Outline • Introduction • Sensors • Modules • Performance • Testbeam • Lab & macro-assembly Other SCT-related talks at STD6: Mike Tyndel “Development of the ATLAS SCT” Allan Clark “Comissioning of the ATLAS SCT” Ulrich Parzefall, University of Freiburg

3. The ATLAS Experiment Ulrich Parzefall, University of Freiburg

4. The Inner Detector Ulrich Parzefall, University of Freiburg

5. The SemiConductor Tracker • SCT made from Silicon Strip Detectors • Key tracking device in ATLAS • Providing four 3-D space points • Radial distance 27 to 56 cm 5.6m 1.2m 2x9 endcap disks in forward region 1976 modules in total with 4 types of modules 4 concentric Si-barrels 2112 modules (one type) Ulrich Parzefall, University of Freiburg

6. Barrel Rectangular sensors with 80μm pitch One sensor type only 64 x 64 mm Parallel strips Manufactured by Hamamatsu Endcaps Fan-shaped sensors with pitch 55 to 95 μm, increasing with radius 5 sensor types Width 46 to 72 mm, length 58 to 65 mm Strips run radially away from beam axis Manufactured by Hamamatsu and CiS Si Detectors in the SCT • Si: p-in-n type FZ in <111> • 285 μm thick • Resistivity 4-8kΩcm • 768 strips • AC-coupling Ulrich Parzefall, University of Freiburg

7. Read-Out EC hybrid • Read-out is binary, using ABCD3T ASIC • Rad-hard (DMILL) • 128 channels, each with preamp & shaper • 132 clock cycles deep pipeline • Common mode can be a show-stopper for binary – to be studied in Lab, testbeam, macro-assembly and full SCT • Hybrid with 12 ASICs • Double-sided flexible Cu/polyimide circuit, laminated on carbon-carbon structure • Optical data transmission and control & trigger • Redundancy against single-point failures Ulrich Parzefall, University of Freiburg

8. Binary & the S-Curve • “Binary” means signal and noise measurements require a threshold scan -> “S-curve” • S-curve is error function (integral of Gaussian) • Signal measurement: 50%-point defines mean charge • Noise measurement: given by “steepness” of drop • SCT module specs: • Efficiency > 99% • Noise Occupancy < 5∙10-4 • Translates into min & max operating threshold • Max Vbias 500V • Less than 15 bad channels (1%) Ulrich Parzefall, University of Freiburg

9. Modules - Forward 12 ABCD3T Readout Chips 128 channels each. Function:Gain, shaping, discrimination, digitization, pipeline memory Silicon detectors 4 6x6 cm2 wafers Glued back to back in pairs either side of spine 768 x 80 mm strips per wafer 40mRad stereo angle TPG Spine with AlN Wings The "backbone" of the module. Provides mechanical support and cooling to detectors Hybrid Cu-kapton circuit wrapped around a C-C substrate Power distribution to chips and optical readout Glass Fan-in with Al Tracks Connecting the detector channels to the hybrid. Ulrich Parzefall, University of Freiburg

10. Modules: Forward • 4 Types of modules • Outer (936) • Middle (640, incl 80 ‘short’) • Inner (400) Outer Inner Middle (Short middle has no end detectors) Ulrich Parzefall, University of Freiburg

11. Modules: Barrel • Sensors • 280 microns thick • Hamamatsu • Max V = 500 5. Hybrid Flex circuit technology Cu / polyimide 280μm thick 12 x ABCD chips. DMILL technology Centrally placed to minimize space conflicts. Bridges sensors (no contact) 2. Stereo angle Upper or lower detector pairs rotated by 40 mRad This gives intrinsic Z resolution of ~ 580mm 3. Location Holes (fix to brackets, one hole & one slot) 30 micron precision • 4. Interfaces • Cooling interface (8x60mm) • ~ 100 m thick grease layer • to aluminium cooling block • Electrical Connector Ulrich Parzefall, University of Freiburg

12. Performance - Testbeam Barrel unirradiated irradiated to max SCT dose • Noise & efficiency specs easily met before irradiation • With increasing radiation dose • Eff. requires threshold increase • N.O. requires threshold reduction • operating window is continuously shrinking Ulrich Parzefall, University of Freiburg

13. Performance - Lab Outers: 1576 Middles: 1529 Inners: 1070 Short Middles: 907 • SCT community built ~4500 modules with yield > 90% • Production spread over large number of assembly sites • Module noise is important parameter • Noise of single EC modules measured in test-box • noise level reflects effective strip lengths of different EC module flavours Ulrich Parzefall, University of Freiburg

14. Performance – Macro-Assembly • Macro-assembly sites mount and test modules on barrels or disks • First time large numbers of modules on SCT structures run together • Noise comparison for barrel modules shows no significant difference Plot of ENC noise for all chips on Barrel 3 at Oxford Ulrich Parzefall, University of Freiburg

15. Performance – Macro-Assembly • EC noise data from C-side disk testing at Liverpool • Strip length determines noise • Noise level on disks in agreement with single-module noise Ulrich Parzefall, University of Freiburg

16. Performance – ATLAS Surface (SR1) • Results from B3 (innermost barrel) • Noise on barrel agrees well with initial noise measurements • Barrel ready to take data… Ulrich Parzefall, University of Freiburg

17. …and it works • First real track in SCT! • Taken May 8 during timing runs • With barrel SCT on surface • Only barrel top sector acvtive Ulrich Parzefall, University of Freiburg

18. SCT Cosmic • One of the first SCT & TRT track seen by reconstruction software • Barrel top sector only Ulrich Parzefall, University of Freiburg

19. Another SCT Cosmic • Later SCT & TRT track seen by reconstruction software • Barrel has now top & bottom sectors working • Meanwhile barrel SCT is installed underground in ATLAS pit Ulrich Parzefall, University of Freiburg

20. Summary • 16k Si-strip detectors • 4k modules • 4 barrels and 18 disks • 1 SCT barrel and 2 SCT end-caps • Barrel tested with cosmics & installed in pit • End-caps in ATLAS surface building & working • SCT getting ready for physics • Thanks to Paul Bell, Allan Clark, Tim Jones, Carlos Lacasta, Heinz Pernegger, Heidi Sandaker, Mike Tyndel, etc Ulrich Parzefall, University of Freiburg

21. Ulrich Parzefall, University of Freiburg

22. THE END • From now on back-up slides and spare plots Ulrich Parzefall, University of Freiburg

23. EC Noise for all C-side modules Ulrich Parzefall, University of Freiburg

24. B3 Noise Occupancy Ulrich Parzefall, University of Freiburg

25. Performance - Macro-Assembly Ulrich Parzefall, University of Freiburg

26. Modules - Forward • The real thing: EC outer module Ulrich Parzefall, University of Freiburg

27. Endcap Assembly: Disk 9C • 9C assembled at Liverpool Ulrich Parzefall, University of Freiburg

28. Thermal Flow in EC Module • Separate cooling paths for ASICs and sensor Ulrich Parzefall, University of Freiburg

29. Channel Defects • 4118 Total Channel Defects • 0.27% of all channels • Average of 4.1 channel defects per module Ulrich Parzefall, University of Freiburg

30. Barrel Modules on B3 with cooling Ulrich Parzefall, University of Freiburg

31. End-cap Outer Module Ulrich Parzefall, University of Freiburg

32. B6 at Oxford Ulrich Parzefall, University of Freiburg