ALICE TPC, Schleching 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

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

ALICE TPC, Schleching The ALICE Detector at LHC

ALICE TPC, Schleching 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 = kHz inelastic collision rate rapidity interval 17 units 25 ns bunch spacing

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

ALICE TPC, Schleching 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 channels, bit time samples (5.7 MHz) event size 60 MB occupancy 40 to dN/dy = 8000 position resolution 800 to 1250  m in r  and z material budget 3.5 to 5% X 0

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

ALICE TPC, Schleching Field Cage parts Drift volume Isolation volume End wheel

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

ALICE TPC, Schleching Inner Field Cage Vessel: Assembly

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

ALICE TPC, Schleching Field Cage Assembly

ALICE TPC, Schleching Checking the End Wheel

ALICE TPC, Schleching Leak test of inner vessel

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

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

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

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

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

ALICE TPC, Schleching Readout Chambers 18 sectors each side, 2 chambers/sector MWPC’s, 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)

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

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

ALICE TPC, Schleching IROC Module Tests HV 1260 … 1310 gas gain 20,000

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

ALICE TPC, Schleching Leak Test

ALICE TPC, Schleching Adjusting Wires vs Pads

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

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

ALICE TPC, Schleching OROC Wiring

ALICE TPC, Schleching 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

ALICE TPC, Schleching 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

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

ALICE TPC, Schleching Laser Rod with Mirrors

ALICE TPC, Schleching 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

ALICE TPC, Schleching 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

ALICE TPC, Schleching 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)

ALICE TPC, Schleching TPC Cooling Scheme

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

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

ALICE TPC, Schleching 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) CHANNELS (CLOSE TO THE READOUT PLANE) FEC (Front End Card) CHANNELS (CLOSE TO THE READOUT PLANE) 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

ALICE TPC, Schleching 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

ALICE TPC, Schleching 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 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

ALICE TPC, Schleching Differential PASA Circuit

ALICE TPC, Schleching Differential Output Signal

ALICE TPC, Schleching Noise performance of PASA

ALICE TPC, Schleching Differential PASA Test Results

ALICE TPC, Schleching 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

ALICE TPC, Schleching cards 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 SSOP mm ALTRO – Summary of Prototyping

ALICE TPC, Schleching 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 mm ALTRO Layout and Package 2.5  m (ST)

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

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

ALICE TPC, Schleching 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

ALICE TPC, Schleching 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

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

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

ALICE TPC, Schleching LV and HV Grounding Scheme

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

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

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

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