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Overview of LC Detectors Mark Oreglia, University of Chicago

Overview of LC Detectors Mark Oreglia, University of Chicago. Outline: Physics drivers The TESLA- NA large design The Silicon Detector concept The Global Large Detector

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Overview of LC Detectors Mark Oreglia, University of Chicago

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  1. Overview of LC DetectorsMark Oreglia, University of Chicago Outline: Physics drivers The TESLA-NAlargedesign The Silicon Detector concept The Global Large Detector Thanks to: Bambade, Barklow, Behnke, Brau, Breidenbach, Damerell, Miller, Ronan, Schumacher, Sugimoto, Torrence, Woods, … Mark Oreglia, SLAC MDI Workshop

  2. 3 Archetype Physics Topics • Light Higgs -- tracker • Best recoil mass resolution in Z-> dileptons • Strong EWSB -- calorimeter • Important to look at WW scattering • W/Z jet separation crucial • Some SUSY scenarios -- hermeticity • Cosmology “benchmarks” summarized: • “bulk” -> cc annihilation -> smuon/selectron • “coannihilation” -> c-stau annihil. -> staus • Low angle backgrounds Mark Oreglia, SLAC MDI Workshop

  3. Momentum Resolution • e+e-gZHgllX • Golden physics channel! • d(1/p) = 7 x 10-5/GeV • 1/10 LEP !!! • goal: dMmm <0.1x GZ • dMHdominated by beamstrahlung Mark Oreglia, SLAC MDI Workshop

  4. Impact Parameter • dd= 5 mm Å 10/p(GeV) mm • 1/3 SLD !!! • excellent flavor tagging capabilities for charm and bottom quarks • Need exceptional tagging for reducing combinatorial background in multi-jets ... • Charge assignment • Asymmetry measurements • (measurement of Higgs BRs not so sensitive!) • The big question: inner VTX radius • No simple answer – physics reach gains with lever arm and background suppresion, esp low momentum particles • … thus, low MS, small radius is essential • Needs more validation, but we are talking 1.5 cm radius! • Instrument lifetime issue • Here we need you to tell us what is possible Mark Oreglia, SLAC MDI Workshop

  5. (Jet) Energy Resolution • dE/E = 0.3/ÖE(GeV) • <1/2 LEP !!! • DMDijet ~ GZ/W • separation between e+e-gnnWWgnnqqqq and e+e-gnnZZgnnqqqq Mark Oreglia, SLAC MDI Workshop

  6. Particle Flow • reconstruction of multijet final states • e+e- H+H-  tbtb  bqqb bqqb • Emphasis on combined systems now • System compataibility means fine granularity in calorimeters (1 cm2 !!!) • Digital mode possible, if backgrounds controllable Mark Oreglia, SLAC MDI Workshop

  7. Hermeticity • hermetic down to q = 5 mrad • Important physics with missing energy topologies (SUSY , extra-dim, Higgs, ...) • Background issues • Ability to veto low-pT particles • Crossing angle optimization • Excellent physics motivation: SUSY-stau • DeRoeck’s talk here • Bambade & Lohman in Forward Region session Mark Oreglia, SLAC MDI Workshop

  8. IR-Related Issues • Good measurements in the low-angle region • Need to make pT cuts for physics analyses • Need to mask and reduce occupancies in low angle region • Need convincing? See Bambade’s summary of X-angle mtg • Beam-beam interaction • broadening of energy distribution (beamstrahlung) • ~5% of power at 500 GeV • backgrounds • e+e- pairs • radiative Bhabhas • low energy tail of disrupted beam • neutron “back-shine” from dump • hadrons from gamma-gamma Mark Oreglia, SLAC MDI Workshop

  9. Time Structure: 5 Bunch Trains/s Dtbunch=337ns • Event rates: Luminosity: 3.4x1034 cm-2 s-1 (6000xLEP) • e+e-gqq,WW,tt,HX 0.1 / train e+e-ggggX:~200 /Train • Background from Beamstrahlung: 6x1010 g/BX 140000 e+e-/BX + secondary particles (n,m)  Large B field and shielding But still: 600 hits/BX in Vtx detector 6 tracks/BX in TPC E=12GeV/BX in calorimeters E 20TeV/BX in forward cals. High granularity of detectors and fast readout for stable pattern recognition and event reconstruction Mark Oreglia, SLAC MDI Workshop

  10. IR Issues pairs Hits/bunch train/mm2 in VXD, and photons/train in TPC Mark Oreglia, SLAC MDI Workshop

  11. Beam Energy • need to know <E>lumi-weighted • Some analyses require better than 0.1% • techniques for determining the lumi-weighted <ECM>: • energy spectrometers • Bhabha acolinearity • Other possibilities : • gZ, ZZ and WW events; use existing Z and W mass • utilize Bhabha energies in addition to Bhabha acol • m-pair events; use measured muon momentum • 200 ppm feasible; 50 ppm a difficult challenge Top-mass: need knowledge of E-spread FWHM to level of ~0.1% Mark Oreglia, SLAC MDI Workshop

  12. Crossing Angle Mark Oreglia, SLAC MDI Workshop

  13. Summary of MDI Issues • Detector designers need input from MDI experts: • Minimum VTX radius (smaller than you’d like!) • Masking optimization and best model (MC tool) for backgrounds • Feasibility of crossing angle options • Detector designers need MDI experts to appreciate: • Need for small on systematic <E>lumi • Need for reduction in low-angle background • Need for diagnostic instrumentation • This talk continues with a description of current designs • New tools are causing all to be rethought • I’ve completely neglected the special requirements of a detector optimized for g-g or e-g collisions • Even worse low-angle background problems Mark Oreglia, SLAC MDI Workshop

  14. There are currently 3 Detector Concepts • The WorldWide Study is working on a plan: • organization of effort • benchmarking performance • cdr/tdr’s • selection • 3 concepts are materializing: • The TESLA concept: TPC-tracker • Silicon tracker + calorimetry (SiD) • new large magnetic volume concept (Global Large Detector, GLD) • Rethinking as new information available Mark Oreglia, SLAC MDI Workshop

  15. Comparison of 3 Concepts(thanks to Y. Sugimoto) • Very large R • Jet chamber or TPC • Scintilator/W-Pb-Fe • Moderate R • TPC tracker • SiW ECAL • Si tracking and ECAL • Small R • Smallest granularity Mark Oreglia, SLAC MDI Workshop

  16. TESLA (and NA Large Det)(Thanks to Ties Behnke, Mike Ronan, Markus Schumacher) Mark Oreglia, SLAC MDI Workshop

  17. Basic TESLA Detector Concept Large gaseous central tracking device (TPC) High granularity calorimeters High precision microvertex detector All inside magnetic field of 4 Tesla No hardware trigger, dead time free continous readout for complete bunch train (1ms) Zero suppression, hit recognition and digitisation in FE electronics Mark Oreglia, SLAC MDI Workshop

  18. Overview of tracking system Central region: Pixel vertex detector (VTX) Silicon strip detector (SIT) Time projection chamber (TPC) Forward region:Silicon disks (FTD) Forward tracking chambers (FCH) (e.g. straw tubes, silicon strips) • B=4T, RTPC=1.7m: momentum resolutiond(1/p) < 7 x 10-5 /GeV • American version has larger TPC outer radius (2m), lower B (3T) • looking at various TPC pad designs and readout Mark Oreglia, SLAC MDI Workshop

  19. Vertex Detector: Conceptual Design Impact parameter: sd ~R1 spoint • 5 LayerSilicon pixel detector • Small R1: 15 mm(1/2 SLD) • Pixel Size:20x20mm2 sPoint =3 mm • Layer Thickness: <0.1%X0 suppression of g conversions – ID of decay electrons minimize multiple scattering 800 million readout cells Hit density: 0.03 /mm2 /BX at R=15mm a pixel sensors Read out at both ladder ends in layer 1: frequency 50 MHz, 2500 pixel rows acomplete readout in: 50ms ~ 150BX <1% occupancy no problem for track reconstruction expected Mark Oreglia, SLAC MDI Workshop

  20. M e.g. vertex mass l/sl Expected resolution in r,f and r,z s ~ 4.2 Å4.0/pT(GeV) mm • LEP-c Flavour Tagging • Powerful flavour tagging techniques (from SLD and LEP) • charm-ID: improvement • by factor 3 w.r.t SLD Mark Oreglia, SLAC MDI Workshop

  21. Gaseous or Silicon Central Tracking? gaseous silicon advantages of gaseous tracking: many points simple pattern recognition redundancy “but be careful with these comparisons!” This is something of an aesthetic argument Mark Oreglia, SLAC MDI Workshop

  22. Forward Tracking 250 GeV m FTD:7 Disks 3 layers of Si-pixels 50x300mm2 4 layers of Si-strips srf= 90mm FCH:4 Layers Strawtubes or Silicon strips (double sided) Mark Oreglia, SLAC MDI Workshop

  23. 60 % charged particles:30 % g:10 %KL,n KL,n p g Particle / Energy Flow The energy in a jet is: Reconstruct 4-vectors of individual particles avoiding double counting Charged particles in tracking chambers Photons in the ECAL Neutral hadrons in the HCAL (and possibly ECAL) • need to separate energy deposits from different particles • small X0 and RMoliere: compact showers • high lateral granularity D ~ O(RMoliere) • large inner radius L and strong magnetic field e • Discrimination between EM and hadronic showers • small X0/lhad • longitudinal segmentation Mark Oreglia, SLAC MDI Workshop granularity more important than energy resolution

  24. Calorimeter Conceptual Design • ECALandHCAL inside coil • large inner radius L= 170 cm good effective granularity Dx~BL2/(RM Å D) 1/p Dx distancebetween charged and neutral particle at ECAL entrance • ECAL: SiW, • 40 layers/24Xo/0.9lhad, 1cm2 lateral segmetation • sE/E = 0.11/ÖE(GeV) Å 0.01 • HCAL: many options • scintilator tiles, analog or digital • steel-scintillator sandwich Mark Oreglia, SLAC MDI Workshop

  25. Forward Calorimeters TDR version of mask L* = 3 m Tasks: Shielding against background Hermeticity / veto LAT: Luminosity measurement from Bhabhas (83 to 27 mrad) SiW Sampling Calorimeter aim for DL/L ~ 10-4 require Dq = 1.4 mrad LCAL:Beam diagnostics and fast luminosity (28 to 5 mrad) ~104 e+e— pairs/BX 20 TeV/BX 2MGy/yr Need radiation hard technology: SiW, Diamond/W Calorimeter or Scintillator Crystals Mark Oreglia, SLAC MDI Workshop

  26. SiD Design Starting Point(Thanks to Marty Breidenbach, John Jaros)B = 5T Recal = 1.25m Zecal = 1.74m Mark Oreglia, SLAC MDI Workshop

  27. The SiD Rationale Premises: particle flow calorimetry will deliver the best possible performanceSi/W is the right technology for the ECAL Excellent physics performance, constrained costs Si/W calorimetry for excellent jet resolution therefore… • Limit Si/W calorimeter radius and length, to constrain cost • Boost the B field to recover BR2 for particle flow, improve momentum resolution for tracker, reduce backgrounds for VXD • Use Si microstrips for precise tracking Mark Oreglia, SLAC MDI Workshop

  28. Cost (and physics) balance R and B High Field Solenoid and Si/W Ecal are major cost drivers. Magnet Costs  Stored Energy  (SiD ~1.1GJ  80-100 M$) Cost [M$] Fix BR2=7.8, tradeoff B and R  Stored Energy [GJ] Delta M$ vs B, BR2=7.8 [Tm2] Mark Oreglia, SLAC MDI Workshop

  29. ECAL Mark Oreglia, SLAC MDI Workshop

  30. Si Detector/ Readout Chip Readout ~1k pixels/detectorwith bump-bonded ASIC Power cycling – only passive cooling required Dynamic range OK(0.1 - 2500 mip) Pulse Height and Bunch Label buffered 4 deep to accommodate pulse train Mark Oreglia, SLAC MDI Workshop

  31. HCAL • Inside the coil • Rin= 1.42m; Rout= 2.44m • 4 Fe (or W, more compact)2cm Fe, 1cm gap • Highly segmented1x1 cm2 – 3x3 cm2~ 40 samples in depth • Technology?RPCScint TileGEM S. Magill (ANL)…many critical questions for the SiD Design Study: thickness? Segmentation? Material? Technology? Mark Oreglia, SLAC MDI Workshop

  32. Silicon Tracking Why silicon microstrips? SiD starting point Robust against beam halo Thin, even for forward tracks. Won’t degrade ECALStable alignment and calibration.Excellent momentum resolution p/p2~2 x 10-5 Mark Oreglia, SLAC MDI Workshop

  33. VXD Tesla SiD Shorten barrel, add endcaps. Shorten Barrel CCDs to 12.5cm (vs. 25.0cm)  add 300 m Si self-supporting disk endcaps (multiple CCDs per disk) This extends 5 layer tracking over max , improves forward pattern recognition. improve  Coverage, improve impact param 5 CCD layers .97 (vs. .90 TDR VXD) 4 CCD layers .98 (vs. .93 TDR VXD) Readout speed and EMI are big questions. Mark Oreglia, SLAC MDI Workshop

  34. SiD Subsystems So far, we’ve concentrated on calorimetry, tracking, and magnet, since they define SiD architecture. Other subsystems need development & integration. • Flux Return/Muons/Had Tail CatcherB field homogeneity for forward ecal?Longitudinal segmentation?Technology? • Very Forward TrackingPixels or strips? • Very Forward Cal (huge and active area!)Active masks and vetoesLumcalBeamcal (pair monitor) Mark Oreglia, SLAC MDI Workshop

  35. Global Large Detector(Thanks to Y. Sugimoto) Mark Oreglia, SLAC MDI Workshop

  36. Basic design concept •  Detector optimized for Particle Flow Algorithm (PFA) • Large/Huge detector concept • GLC detector as a starting point • Move inner surface of ECAL outwards to optimize for PFA • Larger tracker to improve dpt/pt2 • Re-consider the optimum sub-detector technologies based on the recent progresses • Different approaches • B Rin2 : SiD • B Rin2 : TESLA • B Rin2 : Large/Huge Detector Mark Oreglia, SLAC MDI Workshop

  37. Optimization for PFA • Jet energy resolution • sjet2 = sch2 + sg2 + snh2 + sconfusion2 + sthreashold2 • Perfectparticleseparation: • Charged-g/nh separation • Confusion of g/nh shower with charged particles is the source of sconfusion  Separation between charged particle and g/nh shower is important • Charged particles should be spread out by B field • Lateral size of EM shower of g should be as small as possible ( ~ Rmeffective: effective Moliere length) • Tracking capability for shower particles in HCAL is a very attractive option  Digital HCAL Mark Oreglia, SLAC MDI Workshop

  38. Merits and demerits of Large/Huge detector • Merits • Advantage for PFA • Better pt and dE/dx resolution for the main tracker • Higher efficiency for long lived neutral particles (Ks, L, and unknown new particles) • Demerits • Cost ? – but it can be recovered by • Lower B field of 3T (Less stored energy) • Inexpensive option for ECAL (e.g. scintillator) • Vertex resolution for low momentum particles • Lower B requires larger Rmin of VTX because of beam background • d(IP)~5  10/(pbsin3/2q) mm is still achievable using wafers of ~50mm thick Mark Oreglia, SLAC MDI Workshop

  39. Forward Detector components • Si forward disks / Forward Calorimeter • Tracking down to cosq=0.99 • Luminosity measurement • Beam calorimeter • Not considered in GLC detector • At ILC, background is 1/200. Need serious consideration • Careful design needed not to make back-splash to VTX • Minimum veto angle ~5mrad (?)  Physics • Si pair monitor • Measure beam profile from r-phi distribution of pair-background • Radiation-hard Si detector (Si 3D-pixel) Mark Oreglia, SLAC MDI Workshop

  40. Parameters compared Mark Oreglia, SLAC MDI Workshop

  41. Paramters (cont’d) Mark Oreglia, SLAC MDI Workshop

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