1. ALICE TPC, Schleching 20031 The ALICE TPC Team Project leader: Peter Braun-Munzinger, GSI Darmstadt Deputy project leader: Johanna Stachel, Heidelberg Technical coordinator: Peter Glässel, Heidelberg Bergen D. Röhrich Data acquisition BratislavaB. Sitar 1/2 IROC series production CERN T. Meyer Field cage CERN L. Musa Electronics Copenhagen B.S. Nielsen Laser system KrakowM. Kowalski Simulations Darmstadt GSI H.R. Schmidt ROC engineering, prototyping, series production, simulations Darmstadt TU H. Oeschler Electronics testing Frankfurt R. Renfordt Electronics testing, installation Heidelberg KIP V. Lindenstruth Data acquisition, HLT Heidelberg PIJ. Stachel Electronics, engineering, IROC production, OROC production Lund H.A. Gustafsson Electronics

2. ALICE TPC, Schleching 20032 Outline Overview Field Cage Readout chambers Laser system Cooling system Gas system Readout electronics Performances Outlook

3. ALICE TPC, Schleching 20033 The ALICE Detector at LHC

4. ALICE TPC, Schleching 20034 General Conditions at LHC for Heavy Ion Collisions 5.5 TeV CM-energy (NN) Pb + Pb (and probably lighter ions) rapidity density worst case dN/dy = 8000 8 kHz inelastic collision rate rapidity interval 17 units 25 ns bunch spacing

5. ALICE TPC, Schleching 20035 Central event Pb-Pb dN/dy = 8000 only a 2 deg slice!

6. ALICE TPC, Schleching 20036 Summary of TPC Specs |  | < 0.9 (full length tracks) 845 < r < 2466 mm drift length 2 x 2.5 m, 100 kV, 88  s drift Ne/CO 2 (90/10) 18 x 2 sectors with 2 ROC’s 557 568 channels, 512 10 bit time samples (5.7 MHz) event size 60 MB occupancy 40 to 15% @ dN/dy = 8000 position resolution 800 to 1250  m in r  and z material budget 3.5 to 5% X 0

7. ALICE TPC, Schleching 20037 TPC Field Cage Overview Inner and outer Isolation vessels Aluminum End Plates housing ROC’s Field defining system: strips supported by rods

8. ALICE TPC, Schleching 20038 Field Cage parts 5560 5000 Drift volume Isolation volume End wheel

9. ALICE TPC, Schleching 20039 Inner Field Cage Production Cylinders are fabricated from segments glued together (lashing).

10. ALICE TPC, Schleching 200310 Inner Field Cage Vessel: Assembly

11. ALICE TPC, Schleching 200311 Inner Field Cage Vessel: Guard Rings Potential guard rings glued to inner and outer surface of Inner Field Cage Vessel 100 mm

12. ALICE TPC, Schleching 200312 Field Cage Assembly

13. ALICE TPC, Schleching 200313 Checking the End Wheel

14. ALICE TPC, Schleching 200314 Leak test of inner vessel

15. ALICE TPC, Schleching 200315 Flange of Outer Isolation Volume Forged and machined rings from André Constructions Mécaniques - Grenoble

16. ALICE TPC, Schleching 200316 Field Cage: Central Electrode Single mylar foil 3 sheets glued Carbon fiber frame proven technique (NA48)

17. ALICE TPC, Schleching 200317 Central Electrode: Prototype 25 µm aluminized Mylar on Al frame of 10 cm width, Ø approximately 3 m.

18. ALICE TPC, Schleching 200318 Service Support Wheel Carries front end electronics and services

19. ALICE TPC, Schleching 200319 Service Support Wheel Model 3 sectors SSW 1 sector end plate Train all operations

20. ALICE TPC, Schleching 200320 Readout Chambers 18 sectors each side, 2 chambers/sector MWPC’s, 557568 cathode pads gas gain 2x10 4 gated pad sizes 4x7.5, 6x10, 6x15 mm 2 pad occupancy 15 … 40% (dN/dy = 8000) 5.7 MHz 10 bit ADC sampling, 512 samples position resolution 800 … 1250  m (r , z)

21. ALICE TPC, Schleching 200321 Readout Chamber Wire Geometry gate wires cathodes anodes pads

22. ALICE TPC, Schleching 200322 Pad Plane optimized pad sizes 4 x 7.5 mm 6 x 10 mm 6 x 15 mm segmented: IROC and OROC total 557 568 pads

23. ALICE TPC, Schleching 200323 IROC Module Tests HV 1260 … 1310 V @ gas gain 20,000

24. ALICE TPC, Schleching 200324 IROC Gain Homogeneity (Drop at ends due to 55 Fe source geometry)

25. ALICE TPC, Schleching 200325 Leak Test

26. ALICE TPC, Schleching 200326 Adjusting Wires vs Pads

27. ALICE TPC, Schleching 200327 IROC Detail Photos FEE side with one cablePad side before adding anode wire plane

28. ALICE TPC, Schleching 200328 IROC Connected to Front End Card FEC in Cu sandwich 6 cables per FEC

29. ALICE TPC, Schleching 200329 OROC Wiring

30. ALICE TPC, Schleching 200330 IROC Laser Tracks Pad response function  = 2 mm as expected Double track resolution: Separated maxima down to two pad distance Two-gauss fit down to 1 pad

31. ALICE TPC, Schleching 200331 Laser System: Objectives Electronics testing Sector alignment Drift velocity monitoring Pressure, temperature Temperature gradients (stratification, i.e. up-down) ExB, space charge effects Two possible approaches: Relative measurements, rely only on time stability of laser ray position Absolute measurements, requires knowledge of absolute position of laser ray. More ambitious

32. ALICE TPC, Schleching 200332 Laser Rod Principle 4 micro mirrors along z, alignment check with CCD at other TPC end

33. ALICE TPC, Schleching 200333 Laser Rod with Mirrors

34. ALICE TPC, Schleching 200334 Rays perpendicular to beam axis Effective ray  ~1mm 2 x 4 z-planes Strategic boundary crossings Additional signal from central electrode (and pad plane) Laser Ray Pattern

35. ALICE TPC, Schleching 200335 Laser Spatial Accuracy Goals Assembly: angular accuracy ~1 deg. Relative angles of micro-mirror rays measured to 50  rad Final position of laser rays: Stable to better than TPC resolution Known to better than TPC resolution via internal calibration with respect to central electrode and ROC (signal from pad plane) Gives absolute measurement if E-field is near- perfect

36. ALICE TPC, Schleching 200336 Cooling: Temperature Stabilization and Homogeneity Clearly a challenging item: we aim at  T  0.1 K Double defense line strategy: Outer thermal screens toward TRD and ITS ROC al bodies and pad planes: water-cooled Direct water cooling of FEE boards (Cu sheet sandwich) Simulations and tests look promising An important concern: resistor rods (4 x 8 W)

37. ALICE TPC, Schleching 200337 TPC Cooling Scheme

38. ALICE TPC, Schleching 200338 Resistor Rod Cooling gas cooled water cooled High-resistivity water 10 G10 Separator Resistor Cu-heat bridges Ceramic pipeResistor insulation volume (gas) gnd100 kV

39. ALICE TPC, Schleching 200339 TPC Gas System  Ne/CO 2 (90/10), high purity: < 5 ppm O 2  expensive gas -> recirculation,  low purge, ‘breathing’ system

40. ALICE TPC, Schleching 200340 anode wire pad plane drift region 88  s L1: 5  s 200 Hz PASA ADC Digital Circuit RAM 8 CHIPS x 16 CH / CHIP 8 CHIPS x 16 CH / CHIP CUSTOM IC (CMOS 0.35  m) CUSTOM IC (CMOS 0.25  m ) DETECTOR FEC (Front End Card) - 128 CHANNELS (CLOSE TO THE READOUT PLANE) FEC (Front End Card) - 128 CHANNELS (CLOSE TO THE READOUT PLANE) 570132 PADS 1 MIP = 4.8 fC S/N = 30 : 1 DYNAMIC = 30 MIP CSA SEMI-GAUSS. SHAPER GAIN = 12 mV / fC FWHM = 190 ns 10 BIT < 10 MHz BASELINE CORR. TAIL CANCELL. ZERO SUPPR. MULTI-EVENT MEMORY L2: < 100  s 200 Hz DDL (4096 CH / DDL) Power consumption: < 40 mW / channel Power consumption: < 40 mW / channel gating grid FEE Architecture

41. ALICE TPC, Schleching 200341 36 sectorsFRONT VIEW IROC OROC FEC C1 : 18 FECs C6 : 20 FECs C4 : 20 FECs C3 : 18 FECs C2 : 25 FECs C5 : 20 FECs SIDE VIEW 128 channels Front End Card (FEC) FEE POWER:  CHANNEL: 40 mW  BOARD: 6.9 W  SECTOR: 832 W  TOTAL: 30.2 kW Capton Cable 140mm 190mm Mounting FEE

42. ALICE TPC, Schleching 200342 Local Controller DDL - INT Slow-Control Interface TTC-RX BOARD CTRL RCU Slow – Control (1 Mbit – serial link) Detector Link (100 MB / s) (#216) COUNTING ROOM 1 2 25 Each TPC Sector is served by 6 Readout Subsystems Front-end bus (160 MB / sec) Local Slow- Control Serial link ON DETECTOR Overall TPC: 4356 Front End Cards 216 Readout Control Units FEC 128 ch Data Compr. FEC 128 ch FEC 128 ch PASA – ADC – DIG. Global Architecture

43. ALICE TPC, Schleching 200343 Differential PASA Circuit

44. ALICE TPC, Schleching 200344 Differential Output Signal

45. ALICE TPC, Schleching 200345 Noise performance of PASA

46. ALICE TPC, Schleching 200346 Differential PASA Test Results

47. ALICE TPC, Schleching 200347 SAMPLING CLOCK 20 MHz READOUT CLOCK 40 MHz 10- bit 20 MSPS 11- bit CA2 arithmetic 18- bit CA2 arithmetic 11- bit arithmetic 40-bit format 40-bit format 10-bit arithmetic ALICE TPC READOUT CHIP – Principle

48. ALICE TPC, Schleching 200348 4cards 16 ch 135 mm 1998 channels per chip: 1 ADC: 1 external Digital Filter: no 1999 channels per chip: 4 ADC: 4 external Digital Filter: no 2001 channels per chip: 16 ADC: 16 internal Digital Filter: yes Integrated ADCs ALTRO 16 External ADCs (fallback solution) 20 mm 4 PQFP 100 8 SSOP 28 24 mm ALTRO – Summary of Prototyping

49. ALICE TPC, Schleching 200349 7.7 mm 8.3 mm Data Memory 1K x 40 Pedestal Memory 1K x 10 ADC Channel 0 ADC Channel 7 Processing Logic 3.8 mm 12 mm 14.1 mm TQFP 176 24mm ALTRO Layout and Package 2.5  m (ST)

50. ALICE TPC, Schleching 200350 ADC counts Time samples (170 ns) ALTRO Digital Tail Cancellation Performance

51. ALICE TPC, Schleching 200351 ALTRO OUTPUT FILTER DISABLED ALTRO OUTPUT FILTER ENABLED ZERO SUPPRESSION THRESHOLD: 5 ADC COUNTS Digital Tail Cancellation Performance ALTRO test result

52. ALICE TPC, Schleching 200352 The layout of the chip has been optimised to minimise the influence of the digital circuitry on the integrated ADCs. Supply (VCC / GND) for the digital core Supply (VCC / GND) for the ADC The supply voltages for the PASA are distributed on a different plane PCB Design near ALTRO chip

53. ALICE TPC, Schleching 200353 Kapton cables to TPC cooling pipe readout bus connectors control bus connector power supply connector voltage regulators current monitoring & supervision ALTROs Shaping Amplifiers GTL transceivers (back side) Final Front-end Card Prototype 4 chips ALTRO, PASA on other side PCB’s delivered Feb 02 one type of FEC only! 128 ch

54. ALICE TPC, Schleching 200354 PCI CARD (PLDA) FEC- INTERFACE (PMC CARD) PCI CARD PMC-PCI DDL-SIU CONNECTOR Readout Control Unit (RCU) Prototype PCI Card + Mezzanine Card

55. ALICE TPC, Schleching 200355 Electronics Testing Tasks defined and assigned to teams Frankfurt, Lund, TU Darmstadt, Bergen, CERN, Heidelberg A formidable task

56. ALICE TPC, Schleching 200356 LV and HV Grounding Scheme

57. ALICE TPC, Schleching 200357 Low Voltage: Connection to Power Supplies ~10 t Cu

58. ALICE TPC, Schleching 200358 Track efficiency and momentum resolution > 95 % efficiency @ dN/dy = 8000

59. ALICE TPC, Schleching 200359 PID using dE/dx of TPC dE/dx = 8.5%

60. ALICE TPC, Schleching 200360 ALICE Past and Future ALICE TP 1995 TPC Technical Design Report 2000 2003: complete Field Cage and ROC series production 2004/5 Installation at CERN (above ground) Start of LHC 2007