1. 25 Oct 2011 The Silicon Vertex Detector of the Belle II Experiment IEEE NSS 2011 Thomas Bergauer (HEPHY Vienna) Valencia

2. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 Belle and Belle II SVD Double Sided Sensors Readout System Chip-on-Sensor-Concept Summary 2T. Bergauer (HEPHY Vienna)

3. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 Linac Belle KEKB KEKB and Belle @ KEK (1999-2010) Asymmetric machine: 8 GeV e - on 3.5 GeV e + Center of mass energy: Y(4S) (10.58 GeV) High intensity beams (1.6 A & 1.3 A) Integrated luminosity of 1 ab -1 recorded in total Belle mentioned explicitly in Physics Nobel Prize announcement to Kobayashi and Maskawa ~1 km in diameter KEKB Belle Linac About 60km northeast of Tokyo T. Bergauer (HEPHY Vienna)3

4. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 SuperKEKB and Belle II (2010–2014) Aim: super-high luminosity ~8  10 35 cm -2 s -1  1  10 10 BB / year –Refurbishment of accelerator and detector required Schedule: –LoI published in 2004 –TDR was written in 2010 –Construction 2010-2014 –Commissioning 2014-2015 –Operation 2015 onwards http://belle2.kek.jp T. Bergauer (HEPHY Vienna)4

5. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 Belle Silicon Vertex Detector (SVD) Present SVD limitations are –occupancy (currently ~10% in innermost layer)  need faster shaping –dead time (currently ~3%)  need faster readout and pipeline Belle II needs detector with –high background tolerance –pipelined readout –robust tracking –low material budget in active volume Current SVD is not suitable for Belle II T. Bergauer (HEPHY Vienna)5

6. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 Previous SVD Layout (until 2010) 4 straight layers of 4" double-sided silicon detectors (DSSDs) Outer radius of r~8.8 cm Up to three 4” sensors are daisy- chained and read out by one hybrid located outside of acceptance region T. Bergauer (HEPHY Vienna)6

7. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 New Layout for Belle II SVD (2014-) New double-layer pixel detector using DEPFET technology Strip layers extend to r~14 cm –6” sensors Every sensor is read out individually (no daisy-chaining) to maintain good S/N  chip-on-sensor concept Double-layer of DEPFET pixels 4 layers of double- sided strip sensors T. Bergauer (HEPHY Vienna)7

8. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 Belle and Belle II SVD Double Sided Sensors Readout System Chip-on-Sensor-Concept Summary 8T. Bergauer (HEPHY Vienna)

9. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 Vendors of 6” DSSD Double sided strip silicon detectors with AC-coupled readout and poly-silicon resistor biasing from 6 inch wafers 9 6” prototypes ordered and delivered from –Hamamatsu (rectangular) –Micron (trapezoidal) T. Bergauer (HEPHY Vienna)

10. The Silicon Vertex Detector of the Belle II Experiment Rectangular Sensors from Hamamatsu HPK re-started production of DSSDs on 6” wafers Old 4” production line was decommissioned We evaluated first three batches so far Quality is constantly improving Technical details (layers 4,5,6): Dimensions: 59.6 x 124.88 mm 2 p-side: 768 strips, pitch: 75 µm n-side: 512 strips, pitch: 240 µm 25 Oct 201110T. Bergauer (HEPHY Vienna)

11. The Silicon Vertex Detector of the Belle II Experiment 11T. Bergauer (HEPHY Vienna)25 Oct 2011 Trapezoidal Sensors from Micron Trapezoidal sensor for forward region Different p-stop layouts on test sensors Atoll p-stop Common p-stop Combined p-stop

12. The Silicon Vertex Detector of the Belle II Experiment Modules for Beam Test Read out by APV25 (CMS) Baby Module used to verify p-stop geometries 12T. Bergauer (HEPHY Vienna)25 Oct 2011 Baby Module Trapezoidal Module

13. The Silicon Vertex Detector of the Belle II Experiment 13T. Bergauer (HEPHY Vienna)25 Oct 2011 Signal-to-noise-ratios Dark colors: non-irradiated, Light colors: irradiated Atoll pattern (half-wide) performs best, both irradiated and non- irradiated Charge accumulation in non-implanted regions after irradiation Test sensors have been Gamma-irradiated with Co-60 (70 Mrad) Tested before and after at CERN beam test (120 GeV hadrons)

14. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 Belle and Belle II SVD Double Sided Sensors Readout System Chip-on-Sensor-Concept Summary 14T. Bergauer (HEPHY Vienna)

15. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 Readout System Concept Prototype readout system exists Verified in several beam tests Scheme shown below T. Bergauer (HEPHY Vienna)15

16. The Silicon Vertex Detector of the Belle II Experiment Readout Chip: APV25 Developed for CMS (LHC) by Imperial College London and Rutherford Appleton Lab –70.000 chips installed 0.25 µm CMOS process (>100 MRad tolerant) 128 channels 192 cell analog pipeline  no dead time 50 ns shaping time  low occupancy Noise: 250 e + 36 e/pF  must minimize capacitive load!!! Multi-peak mode (read out several samples along shaping curve) Thinning to 100µm successful 16T. Bergauer (HEPHY Vienna)25 Oct 2011

17. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 Prototypes Repeater Box Level translation, buffering FADC+PROC (9U VME) Digitization, zero-suppression, hit time reconstruction T. Bergauer (HEPHY Vienna)17

18. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 APV25 – Hit Time Reconstruction Possibility of recording multiple samples (x) along shaped waveform (feature of APV25) Reconstruction of peak time (and amplitude) by waveform fit –Offline now –Hardware later Is used to remove off-time background hits Measurement T. Bergauer (HEPHY Vienna)18

19. The Silicon Vertex Detector of the Belle II Experiment Occupancy Reduction 25 Oct 2011T. Bergauer (HEPHY Vienna)19

20. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 Belle and Belle II SVD Double Sided Sensors Readout System Chip-on-Sensor-Concept Summary 20T. Bergauer (HEPHY Vienna)

21. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 Chip-on-Sensor Concept Chip-on-sensor concept for double-sided readout Flex fan-out pieces wrapped to opposite side (hence “Origami“) All chips aligned on one side  single cooling pipe Side View (below) 21T. Bergauer (HEPHY Vienna)

22. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 Origami Module with 6” HPK DSSD 22T. Bergauer (HEPHY Vienna)

23. The Silicon Vertex Detector of the Belle II Experiment Origami Module Assembly Ingredients: DSSD sensors Kapton PCB and pitch-adapters APV Readout chips Followed by complicated assembly procedure currently verified by all groups interested in ladder assembly T. Bergauer (HEPHY Vienna)25 Oct 201123

24. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 Sketch of the Outermost Ladder (Layer 6) Composed of 5 x 6” double-sided sensors Center sensors have Origami structure Averaged material budget over the full module: 0.55% X 0 ca. 60cm 24T. Bergauer (HEPHY Vienna)

25. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 Ladder Mechanics Carried by ribs made of carbon fiber and Airex foam Very stiff, yet lightweight thanks to the sandwich construction 25 Cooling PipeSensor Support Ribs T. Bergauer (HEPHY Vienna)

26. The Silicon Vertex Detector of the Belle II Experiment CO 2 Cooling Closed CO 2 cooling plant under development Collaboration with CERN First step is to gain experience with open (blow) system 26T. Bergauer (HEPHY Vienna)25 Oct 2011 Control cabinet with touch screen Accumulator Liquid pumps 1.3 m 1.6 m 1.2 m

27. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 Belle and Belle II SVD Double Sided Sensors Readout System Chip-on-Sensor-Concept Summary 27T. Bergauer (HEPHY Vienna)

28. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 Summary KEKB is the highest luminosity machine in the world Upgrade of KEKB and Belle (2010-2014) –40-fold increase in luminosity –Needs upgrades of all sub-detectors New, enlarged Silicon Vertex Detector –DEPFET pixel double-layer –Four double-sided strip layers Strip Detector R&D –6 inch Double Sided Strip Detectors by HPK and Micron Optimal p-stop geometry identified by SNR measurements before and after irradiation –Readout with hit time reconstruction for improved background tolerance –Origami chip-on-sensor concept for low-mass DSSD readout T. Bergauer (HEPHY Vienna)28

29. The Silicon Vertex Detector of the Belle II Experiment Backup Slides follow 25 Oct 2011T. Bergauer (HEPHY Vienna)29 The End.

30. Beam Parameters KEKB Design KEKB Achieved : with crab SuperKEKB High-Current SuperKEKB Nano-Beam Energy (GeV) (LER/HER)3.5/8.0 4.0/7.0  y * (mm) 10/105.9/5.93/60.27/0.42  x (nm) 18/1818/2424/183.2/2.4  y (  m) 1.90.940.85/0.730.059 yy 0.0520.129/0.0900.3/0.510.09/0.09  z (mm) 4~ 65/36/5 I beam (A)2.6/1.11.64/1.199.4/4.13.6/2.6 N bunches 5000158450002503 Luminosity (10 34 cm -2 s -1 ) 12.115380 25 Oct 2011

31. The Silicon Vertex Detector of the Belle II Experiment KEKB accelerator upgrade T. Bergauer (HEPHY Vienna)25 Oct 2011 Crab cavity 3.5GeV e  8GeV e  New beam-pipes with ante-chamber Damping ring for e + New IR with crab crossing and smaller  y * More RF for higher beam current SR beam 31

32. The Silicon Vertex Detector of the Belle II Experiment New dead-time-free pipelined readout and high speed computing systems Faster calorimeter with waveform sampling and pure CsI (endcap) New particle identifier with precise Cherenkov device: (i)TOP or fDIRC. Endcap: Aerogel RICH Si vertex detector with high background tolerance (+2 layers, pixels) Background tolerant super small cell tracking detector KL/  detection with scintillator and next generation photon sensors Belle-II 25 Oct 2011T. Bergauer (HEPHY Vienna)32

33. The Silicon Vertex Detector of the Belle II Experiment T. Bergauer (HEPHY Vienna)25 Oct 2011 Sensor Types and Vendors Layer# of Ladders Rect. Sensors [narrow] Rect. Sensors [wide] Wedge Sensors APVs 61706817850 51404214560 41002010300 381600192 Sum:4916130411902 33

34. The Silicon Vertex Detector of the Belle II Experiment T. Bergauer (HEPHY Vienna) Micron Wafer Layout Teststructures for p-side Teststructures for n-side (no GCD) Baby sensor 1 p-side: 512 strips 50 µm pitch 1 interm. strip n-side: 512 strips 100 µm pitch 1 interm. strip atoll p-stop 3 different GCDs for the n-side Main sensor p-side: 768 strips 75-50 µm pitch 1 interm. strip n-side: 512 strips 240 µm pitch 1 interm. strip combined p-stop Quadratic baby sensors 2,3,4 p-side: 512 strips 50 µm pitch 1 interm. strip n-side: 256 strips 100 µm pitch 0 interm. strip different p-stop patterns 1) atoll p-stop varying distance from strip 2) conventional p-stop varying width 3) combined p-stop varying distance from strip 1) 2) 3) 25 Oct 201134

35. The Silicon Vertex Detector of the Belle II Experiment narrowhalf-narrowhalf-widewide Common Combined Atoll 35T. Bergauer (HEPHY Vienna)25 Oct 2011 p-stop layouts of the test sensors Three different p-stop patterns Per pattern, four zones with different geometry Green: strip implant (n), Red: p-stop

36. The Silicon Vertex Detector of the Belle II Experiment 36T. Bergauer (HEPHY Vienna)25 Oct 2011 eta distribution for atoll p-stop Charge accumulation in unimplanted region

37. The Silicon Vertex Detector of the Belle II Experiment Current Barrel Layout Slanted Sensors Origami Cooling Tubes Hybrid Boards Layer Sensors/ Ladder Origamis/ Ladder LaddersLength [mm]Radius [mm]Slant Angle [°] 32 0 7/8262380 43 1 103908011.9 54 2 1451511517.2 65 3 1764514021.1 25 Oct 2011T. Bergauer (HEPHY Vienna)37

38. The Silicon Vertex Detector of the Belle II Experiment Comparison VA1TA – APV25 VA1TA (SVD) Commercial product (IDEAS) Tp = 800ns (300 ns – 1000 ns) no pipeline <10 MHz readout 20 Mrad radiation tolerance noise: ENC = 180 e + 7.5 e/pF time over threshold: ~2000 ns single sample per trigger APV25 (Belle-II SVD) Developed for CMS by IC London and RAL Tp = 50 ns (30 ns – 200 ns) 192 cells analog pipeline 40 MHz readout >100 Mrad radiation tolerance noise: ENC = 250 e + 36 e/pF time over threshold: ~160 ns multiple samples per trigger possible (Multi-Peak-Mode) 25 Oct 2011T. Bergauer (HEPHY Vienna)38

39. The Silicon Vertex Detector of the Belle II Experiment 25 Oct 2011 Measured Hit Time Precision Results achieved in beam tests with several different types of Belle DSSD prototype modules (covering a broad range of SNR) 2...3 ns RMS accuracy at typical cluster SNR (15...25) Working on implementation in FPGA (using lookup tables) – simulation successful (TDC error subtracted) Origami Module T. Bergauer (HEPHY Vienna)39

40. The Silicon Vertex Detector of the Belle II Experiment Maximum Radiation Length Distribution Kapton CFRPRohacell Pipe APV Coolant Sensor 25 Oct 2011T. Bergauer (HEPHY Vienna)40

41. The Silicon Vertex Detector of the Belle II Experiment Cooling Boundary Conditions Power dissipation per APV: 0.35 W 1 Origami sensor features 10 APVs Total Origami power dissipation: 312 W 354 W dissipated at the hybrid boards Total SVD power dissipation: 666 W Origamis/ Ladder LaddersAPVs Origami APVs Hybrid Layer 6317510340 Layer 5214280 Layer 4110100200 Layer 3080192 25 Oct 201141T. Bergauer (HEPHY Vienna)