1. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 TRD geometry in CBMroot and conclusions for detector module design David Emschermann Institut für Kernphysik Universität Münster

2. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Outline the TRD layout in CBMroot Dec09 the TRD layout in CBMroot Dec09 signal extraction from the TRD modules signal extraction from the TRD modules quadratic chambers and their rotations quadratic chambers and their rotations pad structure inside the modules pad structure inside the modules pad hit rates pad hit rates arrangement of FEBs on the modules arrangement of FEBs on the modules dual sided MWPC prototypes dual sided MWPC prototypes layout of TRD modules in TRD1 layer 1 layout of TRD modules in TRD1 layer 1 summary and outlook summary and outlook

3. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 The TRD in CBMroot 3 stations a 4 layers, 12 layers total 3 stations a 4 layers, 12 layers total 1110 m² surface 1110 m² surface 1,2million channels 1,2million channels positions in z: positions in z: station 1 - 5,1m station 2 – 7,4m station 3 – 9,6m TRD

4. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Signal extraction and rates 2D readout dual MWPC, central PP 3D readout single MWPC, with 50% drift 3D readout single MWPC, with 33% drift AADADA 3333336444 thickness (12 mm) 1 time unit 3 time units 2,6 time units timing 100 kHz/cm² 30 kHz/cm² ? 40 kHz/cm² ? rate At fixed gas thickness, can we build detectors with a thin drift volume for hit rates below ~30 kHz/cm²? AAAA Dataflow

5. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Choice of detector technology In CBMroot we assume the following: the TRD surface is divided into the TRD surface is divided into quadratic modules quadratic modules the modules allow for signal readout the modules allow for signal readout perpendicular to the pad plane perpendicular to the pad plane

6. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 A module with 1 cm² pad size 50 cm 92 x 23 pads (5 x 20 mm) S size

7. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Station 1 – CBMroot Dec09 8x S + 12x M + 36x L sized chambers in each layer Approximate size of pads in cm² Approximate border of 30 kHz/cm² particle rate

8. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Station 2 – CBMroot Dec09 8x S + 12x M + 80x L sized chambers in each layer

9. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Station 3 – CBMroot Dec09 144x L sized chambers in each layer

10. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Quadratic detector modules We build quadratic detectors in 3 different sizes: 1. 50 cm x 50 cm – Small size chambers 2. 75 cm x 75 cm – Medium size chambers 3. 100 cm x 100 cm – Large size chambers Use rectangular pads with fixed width of 5 mmUse rectangular pads with fixed width of 5 mm allowing a fixed chip-chip spacing on the FEBs allowing a fixed chip-chip spacing on the FEBs Scale the pad size by variing the pad lengthScale the pad size by variing the pad length Rotate the chambers by 90° between layersRotate the chambers by 90° between layers to obtain 2D position information to obtain 2D position information Odd layers (1,3) with vertical padsOdd layers (1,3) with vertical pads Even layers (2,4) with horizontal padsEven layers (2,4) with horizontal pads

11. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Rotating the modules – pad view odd layers (1,3) even layers (2,4) vertical pads horizontal pads 5mm x 20mm pads

12. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Detail of modules (S size) A chamber can contain pads of different sizes, here 5mm x 15mm (green) and 5mm x 20mm (yellow). layer 1 layer 2

13. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Station 1 - hits per pad Based on interpolated data from the TSR. Scale the pad size to yield 100 kHz hits per pad maximum. CyranoBermann

14. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Station 2 - hits per pad CyranoBermann

15. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Station 3 - hits per pad size66%scaled CyranoBermann

16. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Chip count for Dec09 geometry for the full CBM TRD in Dec09 layout for the full CBM TRD in Dec09 layout 81984x 16 channel ASICs or 81984x 16 channel ASICs or 41552x 32 channel ASICs 41552x 32 channel ASICs 16 channels / chip 24 channels / chip 32 channels / chip 92 pads some channels are lost at the two ends of each row some channels are lost at the two ends of each row => need to optimise channels/chip for all detectors => need to optimise channels/chip for all detectors 2 2 2 2 2 2 S size

17. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Channels per chip with upcoming 5 mm pad width layout the with upcoming 5 mm pad width layout the chambers have 92, 142 or 192 pads per row chambers have 92, 142 or 192 pads per row pad number not always even multiple of 16 or 32 pad number not always even multiple of 16 or 32 192 pads 32 channels / chip – 16 cm chip spacing 24 channels / chip – 12 cm chip spacing 16 channels / chip – 8 cm chip spacing L size

18. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Positioning front-end boards the neighbor hit trigger requires data exchange the neighbor hit trigger requires data exchange between ajacent pads (ASICs) between ajacent pads (ASICs) it therefore makes sense to place chips reading it therefore makes sense to place chips reading pads of the same row on the same FEB pads of the same row on the same FEB due to fixed pad width (5 mm) there is a common due to fixed pad width (5 mm) there is a common chip-to-chip spacing for all TRD chambers chip-to-chip spacing for all TRD chambers there is too little space on chambers with small there is too little space on chambers with small pads to place the FEBs parallel to the pad plane pads to place the FEBs parallel to the pad plane

19. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 FEB size and arrangement what will be the size of what will be the size of the chip carriers? the chip carriers? what will be the width what will be the width of the FEBs? of the FEBs? vertical orientation of vertical orientation of the FEBs allows for the FEBs allows for higher density of chips higher density of chips data collection from and data collection from and distribution to FEBs is distribution to FEBs is possible on dedicated possible on dedicated buses: buses: slow control bus (blue) slow control bus (blue) optical readout bus (red) optical readout bus (red)

20. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Detector back-panel the bus bar length scales with the pad length of the different detector chamber types the bus bar length scales with the pad length of the different detector chamber types interface board design interface board design with standard layout decoupled from the decoupled from the chamber geometry station 1 layer 1 chamber with 1cm² pads

21. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 FEB communication optical readout board (ORB, red) optical readout board (ORB, red) detector control board (DCB, blue) detector control board (DCB, blue) can act as interface to the outside can act as interface to the outside

22. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 ORB and DCB Zoom on FEB spacing for chambers with 40 mm pad length

23. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Dual sided MWPCs - pictures MuBu:Münster-Bucharest

24. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 MuBu prototype chambers can stand high rates, tested at 100k hits/cm²/s can stand high rates, tested at 100k hits/cm²/s central pad plane with double-sided MWPC central pad plane with double-sided MWPCBut: signal extraction possible only in plane (2D) signal extraction possible only in plane (2D) at maximum 2 pad rows in one module at maximum 2 pad rows in one module resulting in modules with large aspect ratio resulting in modules with large aspect ratio geometrical acceptance only 66% with 1cm² pads geometrical acceptance only 66% with 1cm² pads

25. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 The “real size” TRD prototype TRD station 1 pads too large: (4cm²) beam hole is too small: only 12cm x 5cm need a realistic TRD geometry

26. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 MuBu module modifications Following modifications are required to fit the MuBu chambers into the CBMroot geometry: assume two rows of pads in one detector module assume two rows of pads in one detector module use 5mm wide rectangular pads use 5mm wide rectangular pads scale pad size 1 cm², 2 cm², 4 cm², 8 cm² … scale pad size 1 cm², 2 cm², 4 cm², 8 cm² … resulting in different width of modules resulting in different width of modules extend the module length from 36 cm to 50 cm extend the module length from 36 cm to 50 cm group the modules into quadratic segments group the modules into quadratic segments rotate segments between even and odd layers rotate segments between even and odd layers for good position resolution on both dimensions for good position resolution on both dimensions

27. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Dual MWPCs in TRD1 – layer 1 Layer 1 – vertical pads 48x/24x chambers - 1cm²/2cm² pads 1cm² 2cm² pad size 50 cm

28. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Dual MWPCs in TRD1 – layer 2 Layer 2 – horizontal pads 48x/24x chambers - 1cm²/2cm² pads quadratic segments rotated

29. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Staggered arrangement Staggered arrangement of dual sided MWPCs Staggered arrangement of dual sided MWPCs 8 quadratic => 72 rectangular modules 8 quadratic => 72 rectangular modules 576 MuBu modules in TRD1 and TRD2 576 MuBu modules in TRD1 and TRD2 thickness of each layer increases by a factor 2 thickness of each layer increases by a factor 2 electronics on front- and back-side of layers electronics on front- and back-side of layers

30. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Detailed view of detectors full coverage of the active area - many extra frames full coverage of the active area - many extra frames same number of pads as with quadratical chambers same number of pads as with quadratical chambers MWPCs with 2 rows of 1cm² pads MWPCs with 2 rows of 2cm² pads

31. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Summary & Outlook Dual sided MWPCs could cover 2% of the total Dual sided MWPCs could cover 2% of the total TRD surface (in the inner part of TRD1 and TRD2) TRD surface (in the inner part of TRD1 and TRD2) For the remaining 98% of the TRD, we need For the remaining 98% of the TRD, we need to find a solution and build large area prototypes to find a solution and build large area prototypes We need to settle the chamber technology We need to settle the chamber technology (rate capability vs signal extraction, drift region?) (rate capability vs signal extraction, drift region?) Tests of chambers with realistic dimensions and Tests of chambers with realistic dimensions and pad size are needed. Limiting factors are the pad size are needed. Limiting factors are the anode wire length, pad plane PCB size. anode wire length, pad plane PCB size.

32. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Thank you

33. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Backup

34. Pad sizes & pad capacity With a pad width of the order of 5 mm a particle track will induce signals on 3 adjacent pads. The pad sizes vary in the range of : 5mm x 20mm = 100 mm² ~ 5 pF 5mm x 200mm = 1000 mm² ~ 25 pF Comparable ALICE TRD pads: 6,35mm x 90mm = 571,5 mm² ~ 15-20 pF Giving rise to the above estimated pad capacities for ideal wiretraces (+50% variation is easily possible). Is this input capacitance variation worth noting during the ASIC design?

35. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Dual MWPCs in the center – L1 Layer 1 – vertical pads 48x/24x chambers - 1cm²/2cm² pads

36. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Dual MWPCs in the center – L2 Layer 2 – horizontal pads 48x/24x chambers - 1cm²/2cm² pads

37. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Staggered detectors

38. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Rectangular prototype

39. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Simulations and data rates As input to the data rate estimation MC was provided by Elena for different collision energies, up to 35 GeV. The data rate estimations agree very well between the different input MC sets. We assume 3 firing pads per particle track @ 5mm pad width. 132 Bits raw data are generated by a 1 channel hit. (Timm) Then 100 kHz hit rate per pad are equal to 40 MBit/s data rate.

40. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Station 1 Layer 1 Bits/pad MBit 1

41. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Station 1 Layer 2 Bits/pad MBit 1

42. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Station 1 Layer 3 Bits/pad MBit 1

43. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Station 1 Layer 4 Bits/pad MBit 1

44. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Station 2 Layer 1 Bits/pad MBit 1

45. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Station 2 Layer 2 Bits/pad MBit 1

46. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Station 2 Layer 3 Bits/pad MBit 1

47. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Station 2 Layer 4 Bits/pad MBit 1

48. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Station 3 Layer 1 Bits/pad MBit 1

49. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Station 3 Layer 2 Bits/pad MBit 1

50. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Station 3 Layer 3 Bits/pad MBit 1

51. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Station 3 Layer 4 Bits/pad MBit 1

52. David Emschermann CBM Collaboration Meeting - GSI – 12/04/2010 Data rates for 35 GeV data rate in station 1 data rate in station 1 data rate in station 2 data rate in station 2 data rate in station 3 data rate in station 3 all 3 stations combined all 3 stations combined 2622 GBit/s 2622 GBit/s 3396 GBit/s 3396 GBit/s 3776 GBit/s 3776 GBit/s-------------- 9794 GBit/s 9794 GBit/s = 1,22 TByte/s ============== This saturates the bandwidth of CBM to the FLES. So we need to either reduce the TRD rate or build al larger FLES.