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Vasiliki A. Mitsou CERN HEP 2003, 17-20 April, Athens, Greece

Construction and quality control of the end-cap Transition Radiation Tracker for the ATLAS experiment. Vasiliki A. Mitsou CERN HEP 2003, 17-20 April, Athens, Greece. Introduction : ATLAS detector Transition Radiation Tracker Barrel modules production End-cap wheels production.

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Vasiliki A. Mitsou CERN HEP 2003, 17-20 April, Athens, Greece

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  1. Construction and quality control of the end-cap Transition Radiation Tracker for the ATLAS experiment Vasiliki A. Mitsou CERN HEP 2003, 17-20 April, Athens, Greece

  2. Introduction: ATLAS detector Transition Radiation Tracker Barrel modules production End-cap wheels production Acceptance tests at CERN Gas tightness Wire tension High voltage Straw straightness (WTS) Status of electronics Concluding remarks Outline V. A. Mitsou / CERN

  3. ATLAS Inner Detector concept General requirements: • Combination of central tracker and TRD features • Robust pattern recognition • Bunch crossing rate – 40 MHz (25 ns between interactions) • Interactions per year - 1016 • Selection level (Higgs) ~ 1:1013 V. A. Mitsou / CERN

  4. Length: Total 6802 cm Barrel 148 cm End-cap 257 cm Outer diameter 206 cm Inner diameter 96-128 cm # straws: Total 372 832 Barrel 52 544 End-cap 319 488 # electronic channels 424 576 Weight ~ 1500 kg Transition Radiation Tracker(TRT) Barrel End-caps V. A. Mitsou / CERN

  5. TRT test-beam performance • Threshold: 200 eV • Drift-time measurement efficiency within ±2.5 σ: 87% Two thresholds: 0.2 keV and 5.5 keV For90%electron efficiency,10-2pion rejection V. A. Mitsou / CERN

  6. Barrel modules construction • Production of most of the parts (straws, radiator packs, wire supports, etc) is completed • 60 modules are completed so far (~60%) • Barrel modules construction is expected to end by July 2003 Module testing is expected to end by August 2004 Module gain mapper now operational V. A. Mitsou / CERN

  7. Module gain mapping 25 pulse-height spectra are taken along each wire On-line fits, first scan V. A. Mitsou / CERN

  8. End-cap wheels production status • 2 type-A, 4-plane wheels completed at PNPI (St. Petersburg) • 2 type-B, 4-plane wheels completed at JINR Dubna • All four wheels shipped to CERN – currently under testing • 13 (11) wheels partially assembled at PNPI (JINR) – absence of web circuits • Type-C wheels (staged detector) not in production yet V. A. Mitsou / CERN

  9. Acceptance tests at CERN Reception Dimensional checks Check of electrical connections Gas tightness Wire tension HV (CO2) Gas gain uniformity (WTS) HV (Triple mixture) 8- or 16-plane wheel assembly Fluid tightness Final dimensional checks Repairs Building 154 at CERN: Reception Acceptance Tests Assembly Short Term storage Also at assembly sites V. A. Mitsou / CERN

  10. P-gauge (room) Exhaust Bubbler (26 cm Isopropyl alcohol) 20 mbar max. P-gauge (table) EXHAUST Valve P-display INLET Valve RS-232 RS-232 Ar cylinder 4-plane wheel PCI MIO16 Table #2 T-sensor Interface box PC LABVIEW MainVI.vi Gas tightness setup P-regulator • Test: measurement of pressure loss inside the straws filled with Ar at 20 mbar overpressure • Specification: < 1 mbar/min/bar • Time: 1 day V. A. Mitsou / CERN

  11. Gas tightness results Spec: <1 mbar/min/bar 20ITPNP000002 V. A. Mitsou / CERN

  12. Wire tension: method • Method: mechanical resonance induced by a loudspeaker • Frequency scanning: [240,320] Hz • 32 channels are scanned simultaneously • Spec: 55 < T < 80 g Slippage < 3 g V. A. Mitsou / CERN

  13. Wire tension: results • No systematic wire slippage is observed • Discrepancies between tension measured at CERN and assembly sites under investigation • Wire tension setup is modified to obtain maximum reliability and efficiency V. A. Mitsou / CERN

  14. HV Test (I) 1 Flap in a WEB Test: 1800 V in CO2 Spec: current < 50 nA • The following circuits are checked, at different assembly and acceptance stages: • Ground of WEB- high voltage socket • Ground of ring - high voltage socket • Neighboring high voltage sockets Ground HV socket V. A. Mitsou / CERN

  15. HV Test (II) Current (nA) distribution Wheel 20ITPNPA00001 I > 50 nA V. A. Mitsou / CERN

  16. Wheel Test Station (WTS) Measurement of gas gain (1% accuracy) to derive eccentricity value per straw Gain variation: Specification: 100% straws with DG/G < 10% (400mm) 95% straws with DG/G < 5% (300mm) • 6 points of measurements along each straw • Slow control ( T, P, HV, humidity, gas flow) • Monitoring straws • Electronics calibration • Online/Offline analysis • 4-plane wheel characterization takes ~20 h at CERN V. A. Mitsou / CERN

  17. PNPI Wheel #1 20ITPNPA000001, straw 2/285 DG/G > 12 % WTS: gain variation of one straw PNPI Wheel #2 20ITPNPA000002 R1 R2 R3 R4 R5 R6 Straw 3407 Reference Straw V. A. Mitsou / CERN

  18. WTS: gain variation in one wheel (I) 100% straws DG/G = 10% 400 mm 95% straws DG/G = 5%  300 mm Readout problems PNPI Wheel #1 20ITPNPA000001 V. A. Mitsou / CERN

  19. WTS: gain variation in one wheel (II) Wire deviation > 400 μm: Wire disconnection (400 μm) V. A. Mitsou / CERN

  20. WTS results reproducibility Gain variation (DG/G): Max. error ~ ± 1% RMS < 0.5% V. A. Mitsou / CERN

  21. ASDBLR boards DTMROC board Electronics status • ASDBLR and DTMROC chips ready to start mass production • End-cap FE boards design almost finalized • Barrel FE boards: new, more compact design with fewer connections adopted V. A. Mitsou / CERN

  22. Concluding remarks • Production of TRT barrel models is well under way - 60% of the modules have been constructed so far • End-cap wheels of type A & B are being constructed and delivered to CERN since June 2002 • Acceptance of first 4-plane wheels assembled at PNPI and JINR is successfully ongoing at CERN • No difference between characteristics of wheels (A &B) after assembly and after reception at CERN V. A. Mitsou / CERN

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