1. Origami Chip-on-Sensor Design: Progress and New Developments 19th September 2012 TWEPP 2012, C. Irmler (HEPHY Vienna) TWEPP 2012, Oxford University

2. Outline Introduction Status 2-DSSD Module Cooling Summary 2TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012

3. Motivation Belle II SVD (  M. Friedl) Super KEKB –7 GeV e - on 4 GeV e + –Center of mass energy: Y(4S) (10.58 GeV) 3TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 ~1 km in diameter Super KEKB Belle II Linac About 60km northeast of Tokyo SVD Requirements: –Twice as large –Low material budget –Low occupancy –Fast readout (APV25) –High SNR –Chips closest to sensor strips Origami Chip-on-Sensor Concept

4. The Origami Chip-on-Sensor Concept 4TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 CF reinforced ribs 6” DSSD 1mm Airex sheet 3-layer polyimide PCB Thinned APV25 Connection to Strips: –PA on top side –wrapped PA for bottom Single cooling pipe Trade-off between material budget & SNR 0.55 X 0 (averaged) n-side p-side

5. Belle II SVD 5TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 APV25 chips Cooling pipe Origami ladder Sensor underneath flex circuit Pitch adapter bent around sensor edge End ring (support)

6. Belle II SVD 4 layers of 6” DSSDs Radii: 38/80/105/135 mm 2/3/4/5 sensors per ladder Origami PCBs in L4-6 L3 & edge sensors read out by conventional hybrids 3 different PCB designs 6TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012

7. Outline Introduction Status 2-DSSD Module Cooling Summary 7TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012

8. Origami PCBs 3 types of 3-layer Origami PCBs: –backward (-z), short tail –center (ce), for central sensor, long tail –forward (+z), routed along slanted sensor, complex shape 8TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 -z ce +z

9. Pitch Adapters All available in single- and double-layer designs PA0: short, n-side, glued onto Origami PCB PA1: first half of p-side strips PA2: second half of p- side strips 9TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 Bond pads of single-layer PAs

10. The Evolution of Origami Modules 2008: Introduction of concept 2009: Feasibility shown with 4” DSSD module 2010: First full-size module with 6” DSSD 2011: Re-design to fit mechanical requirements of Belle II SVD ladders, beam test with CO 2 cooling, … 10TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012

11. 2012 How to assemble ladder with two or more Origami PCBs? Not possible sensor by sensor Combined procedure required 2-DSSD Origami module –2 HPK DSSDs –Two types of Origami PCBs (-z and ce) –Single-layer PA0/PA1/PA2 11TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012

12. Outline Introduction Status 2-DSSD Module Cooling Summary 12TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012

13. Assembly Location Kavli IPMU Institute for the Physics and Mathematics of the Universe Belongs to Tokyo University Kashiwanoha Campus New clean room and lab for L6 ladder assembly 13TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 ~30km north of Tokyo

14. Team K. Kamesh (TIFR), C. Irmler (HEPHY), Y. Onuki (Tokyo U.), K. Negishi (Tohoku U.) 14TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 E. Kato (Tohoku U.) N. Shimizu (Tokyo U.)

15. Attaching of PA1 & PA2 15TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 Almost unchanged procedure PAs were aligned to sensor and then picked up with a vacuum jig New: mask to apply glue Ensures uniform thickness Future: cutting plotter mask samples Graphtec CE5000-60

16. Attaching Origami PCBs Wire bonding p-side Placing sensors onto an assembly bench Optical alignment (not done this time) Attaching Airex sheets (in future: 1 per ladder) Glue Origami PCBs –pre-assembled APV chips –first CE –then –z Wire bonding n-side 16TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 -z CE

17. Bend and Glue PA1, PA2 17TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 Already established procedure Micro positioner with vacuum head Masks to dispense glue Pre-bend PA and align vacuum head Align PA to APV and lower down Glue curing Followed by ~2500 wire bonds

18. Final Module in Frame 18TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 Top and bottom views (w/o cooling pipe)

19. Outline Introduction Status 2-DSSD Module Cooling Summary 19TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012

20. Cooling Pipe 20TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 Cooling pipe Single cooling pipe for several ladders –Little space for connections –Outer  1.6 mm Custom fixture to hold the pipe

21. Cooling Contact – Pipe on APV25 Chips Requirements: Re-mountable cooling coil (no glue …) Easy and safe mounting (bond wires …) Electrically isolating Radiation hard material Avoid stress at sensor Efficient heat transfer –large contact area –adjust height differences of APVs –thermally conductive gap pads 2119th September 2012TWEPP 2012, C. Irmler (HEPHY Vienna)

22. Thermal simulations Thermally conductive Gap Pads Heatload/APV: 0.35W Coolant temperature: -20°C Tube: stainless steel AISI 316L, wall 50μm Gap pad: 86/125 Keratherm λ [W/mK]: 1.5W/mK Very soft, 1mm thick Radiation hardness?  Will be tested in October 19th September 2012TWEPP 2012, C. Irmler (HEPHY Vienna)22

23. Pipe Fixture – First Concepts Prototype 'big' screw clamp One part clamp Screws Too bulky Structure is fragile and the contact surface is small Large force necessary to snap tube into the clamp 19th September 2012TWEPP 2012, C. Irmler (HEPHY Vienna)23

24. Pipe Fixture – Improved Design Hinge clamp: PEEK G450 micro water jet cutting –fabrication tolerance: 0.01mm –Max. wall thickness:20mm –Min. inner radius:0.1mm Disadvantage: 2 parts First prototypes delivered Used on 2-DSSD module 19th September 2012TWEPP 2012, C. Irmler (HEPHY Vienna)24

25. Cooling Pipe Mounting Clamp bases glued onto Origami PCB Keratherm strips placed onto APV chips Pipe put into camp bases Clamps closed 25TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012

26. Final Module with Cooling Pipe 26TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012

27. Performance of CO 2 Cooling Three 6” Origami modules were tested in a 120 GeV beam (October 2011) Stable operation of CO2 cooling system for 3 days The sum of bias currents of sensors decreases from >70µA to ~20µA 27TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 Bias current of all 3 modules vs. time CO 2 system off CO 2 system on 24h 4h Pressure reduction for lower temperature

28. 2-DSSD Origami Module Performance A week ago: first source test of new module with CO 2 cooling So far the module works well Ready for beam test in October 28TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 preliminary

29. Outline Introduction Status 2-DSSD Module Cooling Summary 29TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012

30. Summary Origami chip-on-sensor concept adapted to fit requirements of Belle II SVD ladders –6” sensor, three flex designs Assembly procedure extension to full ladder –in progress Design and first prototypes of pipe fixture Recently assembled a 2-DSSD Origami module Beam test and irradiation in October 2012 Start of ladder production scheduled for summer 2013! 30TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012

31. Thank You 31TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012

32. Spare Slides 32TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012

33. Improved Version of One Part Clamp 33TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012

34. Attaching Airex We used one piece per sensor Later we will use a single sheet per ladder 34TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012

35. Attaching Origami hybrids 1.Aligned CE to sensor 2.Lifted it with Origami jig 3.Applied glue 4.Put back onto assembly bench 5.Waited until glue has been cured 6.Removed Origami jig 7.Aligned –z to sensor 8.Repeated from step 2. 35TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012

36. Attaching Origami hybrids 36TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 1 2 3 4 & 5

37. Attaching Origami CE 37TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 12 3 4 5

38. Attaching Origami -z 38TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012

39. Bend and Glue PA1, PA2 – Apply Mask 39TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 4: flatten glue 2 3: dispense glue 1: apply mask 5: remove mask

40. Pre-bend and attach stopper 40TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 Stopper for PAs pre-bended PA 6 align vacuum head to assembly bench and PA design concept of PA stopper

41. Align PA to APV chips 41TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 7: PA to APVs 8: lower down 9: cure glue Bond pads visible

42. Thermally conductive Gap Pad Responsible for Origami cooling: Annekatrin Frankenberger Selection of thermally conductive materials with different properties. 42TWEPP 2012, C. Irmler (HEPHY Vienna)19th September 2012 86/125 Keratherm 2000S40 Bergquist 575-NS Parker Chomerics Sil Pad 800 Bergquist λ [W/m K] 1.52.01.21.6 Hardness [Shore 00] 103070Shore A 91 Thickness [mm] 0.5 - 50.5 – 3.10.5 – 2.50.1 Silicone xx--x Radiation hardness ???x  Gamma irradiation tests (@ Mol in October)

43. Thermal simulations Thermally conductive Gap Pads Heatload/APV: 0.35W Coolant temperature: -20°C Tube: stainless steel AISI 316L, wall 50μm Gap pad: Sil Pad 800 Bergquist λ [W/mK]: 1.6W/mK Hardness Shore A: 91 Thickness: 0.1mm  good contact? Adjusting unevennes? 19th September 2012TWEPP 2012, C. Irmler (HEPHY Vienna)43

44. Tube fixture Displacement simulation Necessary displacement UX = -0.4mm Acting force 1.4N 19th September 2012TWEPP 2012, C. Irmler (HEPHY Vienna)44