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Status of BESIII and upgrade of BESIII

This presentation outlines the current status and upgrade plans of the BESIII detector, including the commissioning of BEPCII/BESIII, performance details of the detector components, achievements in data collection, and goals for upgrades. Key milestones, specifications, and performance indicators are discussed, such as luminosity, beam energy, resolution of detectors, calibration techniques, and milestones in data collection. The text highlights the achievements in data accumulation, commissioning milestones, and the ongoing upgrade efforts to enhance the detector's capabilities. Exciting physics results are anticipated as the upgrade progresses.

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Status of BESIII and upgrade of BESIII

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  1. Status of BESIII and upgrade of BESIII Ming Shao / USTC for the BES Collaboration

  2. Outline • Commissioning of BEPCII/BESIII • Performance of the BESIII detector • Upgrade of BESIII • Summary

  3. BEPC II Storage ring: Large angle, double-ring RF SR RF Beam energy: 1.0-2.3GeV Luminosity: 1×1033 cm-2s-1 Optimum energy: 1.89 GeV Energy spread: 5.16 ×10-4 No. of bunches: 93 Bunch length: 1.5 cm Total current: 0.91 A SR mode: 0.25A @ 2.5 GeV IP

  4. Main parameters achieved in collision mode

  5. BESIII detector SC magnet,1T Magnet yoke RPC MUC TOF, (barrel) 90/ (endcap)110~120ps Be beam pipe MDC, 130 mm CsI(Tl) calorimeter, 2.5%@1GeV

  6. First collision event on July 19, 2008 14 M y’ events collected in 2008

  7. Drift chamber • To measure the momentum of charged particles by their curvature in the magnetic field • 7000 Signal wires: 25 mm gold-plated tungsten • 22000 Field wires: 110 mm Al • Gas: He + C3H8 (60/40) • Momentum resolution@1GeV: Babar: ~110mm BELLE: ~130mm CLEO: ~110mm BESIII: ~130mm

  8. ●Layer 7 ●Layer 22 MDC calibration Reso. 136 mm Eff.: ~ 98% Beam related backgrounds σP=13.7MeV/c Wire reso.

  9. dE/dx resolution dE/dxreso.: 5.80% p K 

  10. BESIII CsI(Tl) crystal calorimeter Babar: 2.67%@1GeV BELLE: 2.2% @1GeV CLEO: 2.2% @1GeV BESIII: 2.5%@1GeV • To measure the energy of electromagnetic particles • Barrel: 5280 crystals，Endcap: 960 crystals • Crystal: (5.2x 5.2 – 6.4 x 6.4) x 28cm3 • Readout: 13000 Photodiodes, 1cm2cm, • Energy range：20MeV – 2 GeV • position resolution: 6 mm @ 1GeV • Tilt angle: theta ~ 1-3o, phi ~ 1.5o

  11. EMC calibration Barrel energy resolution • energy deposit for e+e-gg Position resolution for Bhabha energy resolution for Bhabha events 4.4 mm

  12. PID: TOF system • Barrel: 2*88 BC 408, 2.4 m long, 5cm thick • Endcap：2*48 BC 404 • PMT: Hamamatzu R5924

  13. TOF calibration TOF Barrel:103ps Design：100~110ps (single layer) Endcap TOF：125ps Design：110~120ps

  14. m system : RPC • 9 layer, 2000 m2 • Special bakelite plate w/o lineseed oil • 4cm strips, 10000 channels • Noise less than 0.1 Hz/cm2

  15. MUON Chamber Efficiency Spatial resolution Single counting rate

  16. BESIII commissioning and data taking milestones Mar. 2008: first full cosmic-ray event April 30, 2008: Move the BESIII to IP July 20, 2008: First e+e- collision event in BESIII Nov. 2008: ~ 14M (2S) events collected April 14, 2009 ~100M (2S) events collected May 30, 2009 ~42 pb-1 at continuum collected (3.65 GeV) July 28, 2009 ~200M J/ events collected Peak Lumi. @ Nov. 2008: 1.21032cm-2s-1 Peak Lumi. @ May 2009: 3.21032cm-2s-1

  17. Data accumulated at BESIII Mar. 6 – April 14 May 24 – June 2 100 M (2S) data 42 pb-1 data at 3.65 GeV June 12 – Jul. 28 200 M J/ data

  18. Upgrade of BESIII TOF ! ΔT>3.38 σ separation rate >95.4%(2σ) ΔT>5.60 σ separation rate >99.7%(3σ) Current time resolution can separate kaon/pion of <0.95GeV/c in the middle of barrel We aim at 1.1-1.2GeV/c

  19. Time resolution in BESIII/TOF Non TOF ~60ps Target:Intrinsic time resolution < 45 ps, Total time resolution < 72 ps, corresponding to a K/pi separation capability up to >1.1 GeV (95%C.L.). Upgrade!

  20. TOF Technique - MRPC A 24 gaps Timing MRPC

  21. Beam Test at T10 Efficiency (%) Time resolution(ps) HV (kV) HV (kV) Signal width – TOT (ns) Time distribution (ps)

  22. Schematic view of MRPC TOF endcap barrel

  23. Summary • BEPCII achieved a luminosity of 31032cm-2s-1 • The performance of the BESIII detector reached expectations • 100 M y’ , 200M J/ events have been accumulated; the data quality is good & preliminary results are being obtained • We are expecting exciting physics results • Upgrade of BESIII is undergoing Thank you !

  24. EMC installation

  25. MDC and TOF installation

  26. Be Beam-pipe installation

  27. BESIII moved to IP: precision < 1 mm

  28. MDC Data/MC comparison • Detailed simulation: • Resolution/efficiency of each cell as a function of drift distance, DOCA, Q, HV, Noise, entrance angle, … • Improvements: more data, better understanding, …

  29. Very low electronics noise (EMC)

  30. EMC Data/MC comparison for Bhabha events Dots: data Solid line: MC with background mixing Dash line/shade: MC without background mixing

  31. EMC Data/MC comparison e- e+ p- p+ p

  32. Summary of BESIII performance ●Layer 7 ●Layer 22 Wire reso. Design: 130 mm dE/dxreso.: 5.80% Design：6-8% CsI(Tl) energy reso. Design: 2.5%@ 1 GeV Barrel TOF reso.: 78ps Design：90ps Bhabha

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