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Large/Huge Detector Concept

Large/Huge Detector Concept. 9. Nov. 2004 @7 th ACFA LCWS in Taipei Y. Sugimoto KEK. Background. History of ACFA detector study. 1992 Dec. “JLC-I” report (JLC Detector) 2T solenoid, R=4.5m Compensating EM- and H-CAL, 2.5<R<4.0m Small-cell Jet chamber, 0.45<R<2.3m, L=4.6m

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Large/Huge Detector Concept

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  1. Large/Huge Detector Concept 9. Nov. 2004 @7th ACFA LCWS in Taipei Y. Sugimoto KEK

  2. Background

  3. History of ACFA detector study • 1992 Dec. “JLC-I” report (JLC Detector) • 2T solenoid, R=4.5m • Compensating EM- and H-CAL, 2.5<R<4.0m • Small-cell Jet chamber, 0.45<R<2.3m, L=4.6m • 2001 Nov. “ACFA report” • 2003 Sep. “GLC report” (GLC Detector) • 3T solenoid, R=4m: Pair B.G. suppression • Compensating EM- and H-CAL, 1.6<R<3.4m • Small cell Jet chamber, 0.45<R<1.55m, L=3.1m ( Keep ptmin same as before) Degraded pt res. • 2004 Aug. ITRP technology choice • Good chance to re-start a new detector optimization study • Regional study  Inter-regional (world-wide) study • Milestone: Detector cost estimation at the end of 2005

  4. Large/Huge detector study so far • Actually, discussion on Large/Huge detector study has started before the ITRP decision • Started discussionafter LCWS2004 • Brief presentation at Victoria US WS (Jul.2004) • Presentation at Durham ECFA WS (Sep.2004) • Detector full simulator (JUPITER) construction on going • Discussion on the key components has started still earlier • TPC R&D for GLC detector started in 2003 • R&D for the calorimeter of GLC detector optimized for PFA (digital calorimeter) has proposed in Aug. 2003

  5. Design Concept

  6. Basic design concept • Performance goal (common to all det. concepts) • Vertex Detector: • Tracking: • Jet energy res.:  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

  7. 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

  8. Optimization for PFA • Figure of merit (ECAL): • Barrel: B Rin2/ Rmeffective • Endcap: B Z2/ Rmeffective Rin : Inner radius of Barrel ECAL Z : Z of EC ECAL front face (Actually, it is not so simple. Even with B=0, photon energy inside a certain distance from a charged track scales as ~Rin2) • Different approaches • B Rin2 : SiD • B Rin2 : TESLA • BRin2 : Large/Huge Detector

  9. Effective Moliere Length xg xa Effective Moliere Length = Rm(1+xg/xa) Gap : Sensor + R.O. elec + etc. Absorber W : Rm ~ 9mm Pb : Rm ~ 16mm

  10. Central Tracker • Figure of merit: n is proportional to L if sampling pitch is constant 

  11. A possible modification from GLC detector model • Larger Rmax (2.0m) of the tracker and Rin (2.1m) of ECAL • TPC would be a natural solution for such a large tracker • Keep solenoid radius same:  Somewhat thinner CAL (but still 6l), but does it matter? • Use W instead of Pb for ECAL absorber • Effective Rm: 25.5mm  16.2mm (2.5mm W / 2.0mm Gap) • Small segmentation by Si pad layers or scintillator-strip layers • Put EC CAL at larger Z (2.05m2.8m)  Longer Solenoid • Preferable for B-field uniformity if TPC is used • It is preferable Zpole-tip < l* (4.3m?) both for neutron b.g. and QC support (l* :distance between IP and QC1)

  12. Comparison of parameters [1] GLD is a tentative name of the Large/Huge detector model. All parameters are tentative.

  13. Comparison of parameters

  14. Detector size • EM Calorimeter • Area of EM CAL (Barrel + Endcap) • SiD: ~40 m2 / layer • TESLA: ~80 m2 / layer • GLD: ~ 100 m2 / layer • (JLC: ~130 m2 / layer)

  15. Global geometry (All parameters are tentative)

  16. Global geometry

  17. Global geometry GLD is smaller than CMS “Large” is smaller than “Compact” 

  18. 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

  19. Detector Components

  20. Detector components • EM Calorimeter • Small Rmeff  • W radiator • Make gaps as small as possible • Small segmentation : sseg < Rmeff • Hadron Calorimeter • Options • Absorber: Pb or Fe ? • Sensor: Scintillator or GEM ? • Digital or not digital ? • Tail catcher behind solenoid needed? • Choice of calorimeter options depends on the results of future detector R&D and detector simulation

  21. Detector components • Main tracker • TPC is a natural solution for the Large tracker • Positive ion feedback (2-g background) ? • Study of gas with small diffusion • Small-cell jet chamber as an option (End plate would be much thicker than TPC) • Solenoid magnet • Field uniformity in a large tracking volume (TESLA TDR)

  22. Detector components • Muon system • No serious study for GLD so far • Design of muon system is indispensable for the solenoid/iron-yoke design, which takes large fraction of the total cost • Si inner/outer(?) tracker • Time stamping capability (separation of bunches) • High resolution Si strip det. improves momentum resolution • Si endcap tracker • Improves momentum resolution in the end-cap region where main tracker coverage is limited SIT: s=7mm, 3 layers VTX: s=3mm, 5 layers

  23. 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)

  24. Vertex Detector Relatively low B-field of Large/Huge detector requires larger radius of the innermost layer Rmin (pair background) Detailed simulation of background (pair b.g. and synchrotron b.g. ) is necessary to determine Rmin and beam pipe radius R&D for thin wafer is very important to compensate for the degradation of I.P. resolution atlow momentum due to large Rmin TOF (?) K-p separation by dE/dx of TPC has a gap in 0.9–2 GeV/c TOF system with s=100ps can fill up the gap 1st layer of ECAL or additional detector ? What is the physics case? Detector components

  25. Detector components • TOF (Cont.) Assumptions: d(TOF)=100ps L=2.1m d(dE/dx)=4.5% K-p Separation (s) Momentum (GeV/c)

  26. Status of the study

  27. Full Simulator • Installation of a new geometry into a full simulator “JUPITER” is under way

  28. Charged – g separation • Simulation by A. Miyamoto • Events are generated by Pythia6.2, simulated by Quick Simulator • Particle positions at the entrance of EM-CAL • Advantage of Large/Huge detector is confirmed • Inconsistent with J.C.B’s result  need more investigation F dcut

  29. Charged – g separation • Simulation by J.C. Brient (LCWS2004) e+e-  ZH  jets at Ecm=500GeV SD (6T) TESLA (4T)

  30. Magnet • ANSYS calculation by H.Yamaoka • Field uniformity in tracking region is OK • Geometry of muon detector is tentative. More realistic input is necessary

  31. Other studies • See presentations in parallel sessions and http://ilcphys.kek.jp/

  32. Summary • Optimization study of Large/Huge detector concept has just started • GLC detector is the starting point of the Large/Huge detector, but its geometry and sub-detector technologies will be largely modified • A key concept of Large/Huge detector is optimization for PFA • A milestone of this study is the detector cost estimation scheduled at the end of 2005. A firm report backed up with simulation studies and detector R&D should be written • A lot of jobs including clarification of physics requirements, detector full/quick simulation, and detector R&D are awaiting us • Please join the Kick-off meeting: Date: Nov. 10 Time: 17:30 - 19:30 Place: Room 204

  33. Backup slides

  34. Pair background track density • Beam Calorimeter is placed in the high background region Same sign Opposite sign GLC Parameter, B=4T by T.Aso

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