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LHeC Tracking

LHeC Tracking. A forward look – LHCb Themis Bowcock. 14/6/12. 10 – 300 mrad. p. p. Forward spectrometer. PLB 694 209] → ~ 100,000 bb pairs produced/second (10 4  B factories) Charm production factor ~20 higher!. [PYTHIA]. [CONF-2010-013]. Themis Bowcock 2.

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LHeC Tracking

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  1. LHeC Tracking A forward look – LHCb Themis Bowcock 14/6/12

  2. 10 – 300 mrad p p Forward spectrometer • PLB 694 209] →~ 100,000 bb pairs produced/second (104B factories) Charm production factor ~20 higher! [PYTHIA] [CONF-2010-013] Themis Bowcock 2

  3. Tracking performance • Dipole magnet, polarity regularly switched to cancel systematic effects • New this year: beam optics changed to decouple crossing angles from LHC (V) and spectrometer magnet (H) • Dp/p = 0.4 – 0.6 % (5–100 GeV/c) Beam optics at interaction point Real data! Bs J/y f [CONF-2012-002] • s(mB) = 8 MeV/c2 • ~ 16 MeV/c2[CMS DPS-2010-040] • 22 MeV/c2 Themis Bowcock 3

  4. Vertex detection • VELO (Vertex Locator)21 modules of r-f silicon sensor disksRetracted for safety during beam injection • Reconstructed beam-gas vertices (used for luminosity measurement) • Impact parameter resolution ~ 20 mmProper-time resolution: st = 45 fscf CDF: st = 87 fs[PRL 97 242003] r z Beam Prompt J/y Bs J/y f VELO sensors 7 mm [CONF-2012-002] • [PLB 693 69] Beam 2 Beam 1 Themis Bowcock 4

  5. VELO: Complete half O(300m foil) Using ripples same as cylinder Resolution about 4microns at 6° Themis Bowcock 5

  6. LHeC TRACKER Themis Bowcock 6

  7. Requirements • Tracking requirements (from CDR) • Accurate measurements in pT and θ • Secondary vertexing in maximum polar angle • Resolution of complex, multiparticle, highly energetic states in the fwd direction • Charge identification of scattered electron • Measurement if vector mesons of μ pairs (J/ψ,ϒ) Themis Bowcock 7

  8. Resolution (solenoid) • Resolution approx. • 10 times better than H1 • Similar to ATLAS in central region ~ Themis Bowcock 8

  9. Magnetic Field Themis Bowcock 9

  10. Baseline (A) Themis Bowcock 10

  11. Baseline (A) Themis Bowcock 11

  12. Beam Pipe • Power/cooling? Be(not Al) Very Non-Trivial Very expensive Themis Bowcock 12

  13. Themis Bowcock 13

  14. Layout O(5M strips) + Pixels (~ 25kW) Themis Bowcock 14

  15. Dimensions Themis Bowcock 15

  16. Central Barrel “sat on” shape is non-trivial Themis Bowcock 16

  17. Estimated Performance Themis Bowcock 17

  18. VELO: Material Budget Average is 18.91% X0 Particle exiting the VELO Material Budget (% Xo) Themis Bowcock 18

  19. Impact Parameter LHCb Data Themis Bowcock 19

  20. Polar Angle LHCb Data Themis Bowcock 20

  21. Momentum Resolution LHCb Data Themis Bowcock 21

  22. Heavy Flavour Themis Bowcock 22

  23. Radiation • For the LHCb radiation is a key issue • We chose n+n technology • Pioneered production of n+p (cheaper and does not invert) • Have a spare VELO in case of disaster... Themis Bowcock 23

  24. Radiation Tolerance ISSUE Themis Bowcock 24

  25. Radiation • LHCb pp • At LHCb first hit ~ 10cm from IP on average although we go down to 0.8mm from beam • LHCbdesigned for ~ 5x1014p/cm2 • Upgrade 5x1015p/cm2 • Numbers indicate O(109 p/cm2/yr) LHeC @ 5cm • 5cm sphere -> 300cm2 -> 1013 p/cm2/yr into acceptance • Assuming 107s/yr at 40MHz • Every 25ns < 0.01 particles (Cosmic rate!!) • Beam gas etc accounted for? • Ever take pp collisions? VELO sensors 7 mm • [PLB 693 69] Beam 2 Beam 1 Themis Bowcock 25

  26. Synchrotron Radiation • Important difference with LHCb • Potentially severe problem • Remember Belle destroyed in a few weeks • Also heat into beam pipe .... Themis Bowcock 26

  27. Cooling • For LHCb we used (first time) bi-phase CO2 now adopted by ATLAS/CMS • LHCb in vacuum (makes problem worse) • Each module around 25W • Need to maintain about -7C for sensors • Main power from electronics • Little heat load from foil Themis Bowcock 27

  28. LHeC Cooling • Proposed using same CO2 system • Note though • Small pipes difficult • LHCb cooling has needed “unblocking” twice (Filters) • It is low mass • Complicated (and non-trivial) thermal interface • Lots of ATLAS R&D now • As with GPDs routing cooling & power is a major problem • Geometry not the same so routing is not! Themis Bowcock 28

  29. Requirements • Modular Design • Detector Technologies re-used rather than innovated • HERA, LHC & Upgrades and ILC Themis Bowcock 29

  30. From CDR: Practical Issues • Cost • This IS a big expensive detector • Huge undertaking (At least 4 separate systems) each one of which is complex. • Sensor Type • CDR Suggested p+n technology • MAPS/Planar Si • Radiation Tolerance • MIP and Synchrotron. A CRITICAL ISSUE • FLUKA, BG, (pp?) • Trigger & R/O Electronics • Not addressed here. Re-use CMS/ATLAS? • VELO used full Analog R/O 10bit ADCs • Power and Cooling • A serious undertaking (compact space with 20kW+ just from electronics ) • Mechanical Support & Beampipe • Complex Themis Bowcock 30

  31. Summary • Beautiful (aka challenging) detector to build(!) • High level of performance specified • e, jets • Also with serious flavour tagging capability • Very tight schedule for completion even re-using GPD technology • Will be large undertaking by the community • Do not underestimate the mechanical/electrical engineering required • Small changes are never such Themis Bowcock 31

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