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Status Report of Central Tracker R&D

Status Report of Central Tracker R&D. (in Japan). The 6th ACFA Workshop on Physics and Detector at Linear Collider 15-17 December 2003, TIFR, Mumbai, India. Takashi Watanabe Kogakuin University. Contents. Physics Requirements Current CDC Design (ten years ago) R&D item

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Status Report of Central Tracker R&D

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  1. Status Report of Central Tracker R&D (in Japan) The 6th ACFA Workshop on Physics and Detector at Linear Collider 15-17 December 2003, TIFR, Mumbai, India Takashi Watanabe Kogakuin University

  2. Contents • Physics Requirements • Current CDC Design (ten years ago) • R&D item • What we have achieved • What is left out ? • Summary and Conclusions The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  3. JLC-CDC group • Hiroshima University • KEK • Kinki University • Kogakuin University • Mindanao State University • Nagoya University • Saga University • Tokyo University of Agriculture and Technology • University of Tsukuba 9 Univ. and Lab. The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  4. Recoil Mass Resolution The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  5. Jet Invariant Mass Resolution • Good track-cluster matching • 2-track separation better than 2mm < 10% hit loss at inner most layer for 250GeV W’s The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  6. Time Stamping Capability The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  7. 2T CDC Design The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  8. 2T CDC Design Slow gas mixture Small Lorentz angle 1.2k cells The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  9. Cell Structure (unit: mm) The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  10. 4.6m-long test chamber The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  11. Cell Structure (test chamber) The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  12. Wire Position • Sense wires: W • (30mm diameter) • Field wires: Al • (125mm diameter) (unit: mm) The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  13. Baby Chamber The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  14. R&D Items (Proof of Principle Phase) • Can we control gravitational and electrostatic wire sags for a 4.6m-long wires? • Can we achieve a spatial resolution of 85microns everywhere in this big chamber? • Can we achieve 2-track separation better than 2mm? • Can we stably operate 4.6m-long stereo cells? • Is Lorentz angle small enough to allow straight cells? • Is gas gain saturation observed for cools gas mixtures no problem? • Is tension drop controllable for Al wires? • How well can we time-stamp bunches? • Is neutron BG no problem? (about 3khits/train for B=2T) The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  15. Gravitational Sag The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  16. Electrostatic Sag The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  17. Wire Sag Sense Wires Field Wires uncontrollable discrepancies errors in the coordinate measurement < 80microns/wire The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  18. Tension Measurement • Sense wires No tension drop • Field wires Used Al wires are not appropriate for CDC 10% drop/year 5% drop/year still keeps dropping The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  19. Mechanical Stability • Gravitational and electrostatic wire sag: Predictable with reasonable accuracy • Wire tension drop for Al Field wires: unacceptable • Need better wire material • Fallback solution = e.g. Cu/Be but with a thicker endplates The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  20. R&D Items (Proof of Principle Phase) • Can we control gravitational and electrostatic wire sags for a 4.6m-long wires? • Can we achieve a spatial resolution of 85microns everywhere in this big chamber? • Can we achieve 2-track separation better than 2mm? • Can we stably operate 4.6m-long stereo cells? • Is Lorentz angle small enough to allow straight cells? • Is gas gain saturation observed for cools gas mixtures no problem? • Is tension drop controllable for Al wires? • How well can we time-stamp bunches? • Is neutron BG no problem? (about 3khits/train for B=2T) The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  21. Spatial Resolution • 4.6m-long chamber CO2(90%)/isobutane(10%) Degradation Oxygen Effect? (60ppm) The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  22. Signal charge vs. Drift distance • Signal charge vs. Drift distance (Baby Chamber) The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  23. Oxygen Contamination vs. Resolution • Oxygen Contamination vs. Resolution The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  24. Spatial Resolution • Rapid resolution degradation with drift distance observed for the 4.6m chamber can be attributed to Oxygen contamination • Average spatial resolution of 90microns is possible • This requires, however, sufficiently low Oxygen contamination The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  25. R&D Items (Proof of Principle Phase) • Can we control gravitational and electrostatic wire sags for a 4.6m-long wires? • Can we achieve a spatial resolution of 85microns everywhere in this big chamber? • Can we achieve 2-track separation better than 2mm? • Can we stably operate 4.6m-long stereo cells? • Is Lorentz angle small enough to allow straight cells? • Is gas gain saturation observed for cools gas mixtures no problem? • Is tension drop controllable for Al wires? • How well can we time-stamp bunches? • Is neutron BG no problem? (about 3khits/train for B=2T) The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  26. 2-track event • 2-track event (Baby Chamber) Up stream Down stream The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  27. Efficiency • Efficiency The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  28. 2-track separation • 2-track separation of 2mm of better seems possible for normal incidence • Slight degradation of spatial resolution observed for the 2nd hit whose effect may be estimated by MC simulation The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  29. R&D Items (Proof of Principle Phase) • Can we control gravitational and electrostatic wire sags for a 4.6m-long wires? • Can we achieve a spatial resolution of 85microns everywhere in this big chamber? • Can we achieve 2-track separation better than 2mm? • Can we stably operate 4.6m-long stereo cells? • Is Lorentz angle small enough to allow straight cells? • Is gas gain saturation observed for cools gas mixtures no problem? • Is tension drop controllable for Al wires? • How well can we time-stamp bunches? • Is neutron BG no problem? (about 3khits/train for B=2T) The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  30. Shrink Factor E0 (kV/cm) 304.2 303.8 303.4 303.0 Z (cm) How dose this affect gas gain and operational stability? The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  31. Gain Stability 10 1 Q (pC) 0.1 Operation Region 0.01 Gain variation < 25% (4.6m) 200 250 300 350 E (kV/cm) The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  32. Stereo Wire Geometry • Design procedure (how to decide stereo angles and layer-to-layer spacing, etc.) for stereo wire geometry has been worked out • Gain variation along stereo wires due to cell shrinking is at worst 25% for 2T(4.6m) design and is tolerable The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  33. R&D Items (Proof of Principle Phase) • Can we control gravitational and electrostatic wire sags for a 4.6m-long wires? • Can we achieve a spatial resolution of 85microns everywhere in this big chamber? • Can we achieve 2-track separation better than 2mm? • Can we stably operate 4.6m-long stereo cells? • Is Lorentz angle small enough to allow straight cells? • Is gas gain saturation observed for cools gas mixtures no problem? • Is tension drop controllable for Al wires? • How well can we time-stamp bunches? • Is neutron BG no problem? (about 3khits/train for B=2T) The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  34. Lorentz Angle • Measurement Principle The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  35. E dependence tan a 0.6 0.8 1.0 1.2 1.4 1.8 E (kV/cm) The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  36. B dependence tana = 0.159+0.002 tan a B (T) The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  37. Lorentz Angle • Measured Lorentz angles are well reproduced by Garfield/MagBoltz calculations • Measured Magnetic deflection coefficient is consistent with unity, justifying extrapolation to higher magnetic field • The current cell design is OK for 2T operation The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  38. R&D Items (Proof of Principle Phase) • Can we control gravitational and electrostatic wire sags for a 4.6m-long wires? • Can we achieve a spatial resolution of 85microns everywhere in this big chamber? • Can we achieve 2-track separation better than 2mm? • Can we stably operate 4.6m-long stereo cells? • Is Lorentz angle small enough to allow straight cells? • Is gas gain saturation observed for cools gas mixtures no problem? • Is tension drop controllable for Al wires? • How well can we time-stamp bunches? • Is neutron BG no problem? (about 3khits/train for B=2T) The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  39. Gas Gain Measurement • Pulse-height spectra for 55Fe X-ray CO2(90)/isobutane(10) 3rd peak Al Fe The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  40. Gas Gain Measurement • CO2/isobutane is very special in the sense that its gas gain starts saturating at relatively low HV • Good news for neutron BG • Bad news for dE/dx measurements? The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  41. R&D Items (Proof of Principle Phase) • Can we control gravitational and electrostatic wire sags for a 4.6m-long wires? • Can we achieve a spatial resolution of 85microns everywhere in this big chamber? • Can we achieve 2-track separation better than 2mm? • Can we stably operate 4.6m-long stereo cells? • Is Lorentz angle small enough to allow straight cells? • Is gas gain saturation observed for cools gas mixtures no problem? • Is tension drop controllable for Al wires? • How well can we time-stamp bunches? • Is neutron BG no problem? (about 3khits/train for B=2T) The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  42. Time Stamping (Fujii-san’s talk in this morning session) • We can determine T0 on a track by track basis with a time resolution of about 2ns for axial + stereo geometry (3T case) This means we can clearly separate BG tracks that are about 6bunches away The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  43. R&D Items (Proof of Principle Phase) • Can we control gravitational and electrostatic wire sags for a 4.6m-long wires? • Can we achieve a spatial resolution of 85microns everywhere in this big chamber? • Can we achieve 2-track separation better than 2mm? • Can we stably operate 4.6m-long stereo cells? • Is Lorentz angle small enough to allow straight cells? • Is gas gain saturation observed for cools gas mixtures no problem? • Is tension drop controllable for Al wires? • How well can we time-stamp bunches? • Is neutron BG no problem? (about 3khits/train for B=2T) YES YES YES YES YES YES OK for 3T YES ??? The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  44. Remaining R&D Itmes • Proof of principle phase • BG studies with Full Detector Simulation • Tension drop problem (OK for 3T option) • Engineering Design Phase • Charge division • Prototype chamber with stereo layers • Readout electronics • DAQ The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

  45. Conclusions • Most of R&D questions in Proof of Principle phase have been answered affirmatively. This means that original R&D goals are basically achieved. • Next phase is engineering design, which requires a full scale prototype test. or • We will seek for other possibilities . (e.g. TPC) The 6th ACFA Workshop on Physics and Detector at Linear Collider Takashi Watanabe (Kogakuin University)

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