1. A Low Mass On-chip Readout Scheme for Double-sided Silicon Strip Detectors 13th February 2013 C. Irmler, T. Bergauer, A. Frankenberger, M. Friedl, I. Gfall, A. Ishikawa, C. Joo, D.H. Kah, R. Kameswara, K.H. Kang, E. Kato, G. Mohanty, K. Negishi, Y. Onuki, N. Shimizu, T. Tsuboyama, S. Schmid, M. Valentan VCI 2013, 13 th Vienna Conference on Instrumentation

2. Outline Introduction Assembly Cooling Summary 2VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013

3. Motivation 3VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013 ~1 km in diameter Super KEKB Belle II Linac About 60km northeast of Tokyo Super KEKB –Electron-positron collider –7 GeV e - on 4 GeV e + –Center of mass energy: Y(4S) (10.58 GeV) –Target luminosity: ~8  10 35 cm -2 s -1 Belle II detector –Refurbishment of all sub- detectors –40 times higher luminosity –Faster readout

4. Silicon vertex detector 4VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013 Belle II SVD: 4 layers of 6 inch DSSDs Radii 38 to 135 mm Readout: APV25 –40 MHz / Tp= 50 ns –192 cells analog pipeline –ENC = 250 e + 36 e/pF Minimize capacitive load! Chips closest to sensors strips  chip-on-sensor Keep material budget low Belle (SVD2): 4 layers of 4 inch DSSDs Radii: 20 to 88 mm Readout: VA1TA –5 MHz / Tp = 800 ns –no pipeline –ENC = 180 e + 7.5 e/pF Read out from edge of ladders –long pitch adapters –up to 3 ganged sensors

5. The Origami chip-on-sensor concept 5VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013 CF reinforced ribs 6” DSSD 1mm Airex sheet 3-layer flex circuit Thinned APV25 (100µm) 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

6. Belle II SVD Origami ladder Exploded drawing of a L6 ladder 3 different Origami flex designs –backward (-z), short tail –center (ce), for central sensor, long tail –forward (+z), routed along slanted sensor, complex shape 6VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013

7. Outline Introduction Assembly Cooling Summary 7VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013

8. 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 8VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013

9. How to assemble ladder with two or more Origami flexes? Not possible sensor by sensor Combined procedure required 2-DSSD Origami module –2 HPK DSSDs –Two types of Origami flexes (-z and ce) –Single-layer PA0/PA1/PA2 Assembly of a 2-DSSD Origami module 9VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013

10. Attaching of pitch adapters (PA1 & PA2) 10VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013 Align PAs to p-side of sensor Picked up with a vacuum jig Apply mask and glue –Ensures uniform thickness –Future: cutting plotter Place back onto sensor Curing of glue

11. Attaching Origami flexes 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 11VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013 -z CE

12. Bend and glue PA1, PA2 12VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013 PA1 & PA2 have to be bent toward top side Micro positioner with vacuum head Apply glue using masks Pre-bend PA and align vacuum head Align PA to APV and lower down Glue curing Followed by ~2500 wire bonds Custom vacuum nozzle

13. Attaching CF ribs Mount ribs on jig Place rib jig onto assembly bench Dispense glue Place sensors onto ribs Distance given by precise spacers Cure glue Remove spacers and lower down assembly bench 13VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013

14. Outline Introduction Assembly Cooling Summary 14VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013

15. Cooling of Origami APV chips 15VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013 Cooling pipe ~10 W per ladder Efficient CO 2 cooling Single cooling pipe for several ladders –Little space for connections –Outer  1.6 mm Custom fixture to hold the pipe

16. Cooling contact requirements 1613th February 2013VCI 2013, C. Irmler (HEPHY Vienna) Re-mountable cooling pipe (no glue …) Easy and safe mounting (bond wires …) Avoid stress at sensor (thermal expansion) Efficient heat transfer –large contact area –compensate height differences of APVs –thermally conductive gap pads Electrically isolating Radiation hard material

17. Thermally conductive gap pad Heatload/APV: 0.35W Coolant temperature: -20°C Tube: –stainless steel AISI 316L –wall thickness 100μm Gap pad: 86/125 Keratherm –λ [W/mK]: 1.5W/mK –Very soft, 1mm thick –Radiation hardness was tested in October 2012 13th February 2013VCI 2013, C. Irmler (HEPHY Vienna)17

18. Pipe clamp Hinge clamp: PEEK G450 micro water jet cutting –fabrication tolerance: 0.01 mm –Max. wall thickness:20 mm –Min. inner radius:0.1 mm Disadvantage: 2 parts Prototypes tested on 2-DSSD module 13th February 2013VCI 2013, C. Irmler (HEPHY Vienna)18

19. Cooling pipe mounting Clamp bases glued onto Origami PCB Keratherm strips placed onto APV chips Pipe put into camp bases Clamps closed 19VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013

20. Final Module with cooling pipe 20VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013

21. Improved version of clamp 21VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013 Material: PEEK Improved shape Single part Clamp force: ~3 N Prototypes tested on dummy Works well Easy to assemble

22. Performance of CO 2 cooling 22VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013 Temperature measured at 4 locations of the 2-DSSD module Stable operation for ~18 hours Nominal temperature: -20°C All temperatures within precision of probes  no warming of coolant Efficient heat transfer between chips and pipe (coolant) Temperatur [°C] Time Module Inlet Module Outlet Origami –z Origami ce

23. Beam test performance Beam test performed @ CERN SPS in October 2012 120 GeV/c (mainly pions) Module operated with CO2 cooling at -20 °C Signal-to-noise ratio: 23VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013 Many noisy channels due to wire bonding problems (new wire bonder) Origami –z performed well (compared to single-sensor modules) Origami ce suffered from noisy channels

24. Outline Introduction Assembly Cooling Summary 24VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013

25. Summary Origami chip-on-sensor concept –A low mass on-chip readout for 6” DSSD (0.55 X 0 avg.) –Feasibility proven by several prototypes –Will be utilized for the Belle II SVD –Assembly procedure shown for a 2-DSSD module Two-phase CO 2 Cooling: –Single tube for several ladders –Design and prototypes of tube clamp available Beam test @ CERN in October 2012 Ladder production scheduled for autumn 2013! 25VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013

26. Thank You 26VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013

27. Backup Slides 27VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013

28. Belle II SVD 28VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013 APV25 chips Cooling pipe Origami ladder Sensor underneath flex circuit Pitch adapter bent around sensor edge End ring (support)

29. Team K. Kamesh (TIFR), C. Irmler (HEPHY), Y. Onuki (Tokyo U.), K. Negishi (Tohoku U.) 29VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013 E. Kato (Tohoku U.) N. Shimizu (Tokyo U.)

30. 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 30VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013 -z ce +z

31. 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 31VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013 Bond pads of single-layer PAs

32. Attaching Airex We used one piece per sensor Later we will use a single sheet per ladder 32VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013

33. 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. 33VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013

34. Attaching Origami CE 34VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013 12 3 4 5

35. Attaching Origami -z 35VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013

36. Bend and Glue PA1, PA2 – Apply Mask 36VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013 4: flatten glue 2 3: dispense glue 1: apply mask 5: remove mask

37. Final Module in Frame 37VCI 2013, C. Irmler (HEPHY Vienna)13th February 2013 Top and bottom views (w/o cooling pipe)