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BESIII PROJECT

BESIII PROJECT. Zhen ’ An LIU Inst. Of High Energy Physics Representing BEPCII/BESIII Team QWG Meeting Oct. 12-15, 2004 IHEP, Beijing. The B eijing E lectron P ositron C ollider. Linac,Transportation Line,

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BESIII PROJECT

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  1. BESIII PROJECT Zhen’An LIU Inst. Of High Energy Physics Representing BEPCII/BESIII Team QWG Meeting Oct. 12-15, 2004 IHEP, Beijing

  2. The Beijing Electron Positron Collider Linac,Transportation Line, Storage Ring,BES,BSRF L ~ ~51030 /cm2s at J/ peak Ecm~2-5 GeV Construction: 1984-1988 A unique e+e- machine in the -charm energy region since 1989.

  3. BESII Detector (1995-1997 upgrade) VC: xy = 100 m TOF: T = 180 ps  counter: r= 3 cm MDC: xy = 200 m BSC: E/E= 22 % z = 5.5 cm dE/dx= 8.4 %  = 7.9 mr B field: 0.4 T p/p=1.8(1+p2) z = 2.3 cm Dead time/event: 10 ms

  4. BESMain Physics Results Data Taken: 66M J/events, 18Mevents, 33 pb-1(3770)events, 5 pb-1data, 22 pb-1Ds data • Precise Mass Measurement of  lepton. • 2-5 GeV R measurement. • Systematic study of (2S) decays. • Systematic study of J/ decays. ObtainfDs from Ds pure leptonic decay. • Measure Br(DS) in model independent way. • BES has 116 entries in PDG.

  5. The need for upgrade • Interesting physics limited by statistics: glueball/hybrid searches, CKM matrix elements, DDbar mixing, rp puzzle, non-pQCD… • Large systematic error due to limited resolution • Detector is aging • Multi-bunch mode & High event rate On Feb. 10, 2003, the Chinese government, the state council, approved officially the BEPCII/BESIII upgrade project

  6. BEPCII: High Lumi. Large Angle Double–ring Collider 500MHz SC cavity Build new ring inside existing tunnel . Two half new rings and two half old rings cross at two IR’s, forming a double ring collider.

  7. Double ring installation – Wood model No spacing problems

  8. BEPCII Design goal

  9. BEPCII main parameters Passed SLAC review in May 2002.

  10. The BESIII Detector • small cell, He gas based drift chamber • CsI(Tl) crystal calorimeter • Superconducting magnet of 1T • PID system based on TOF • RPC muon chamber system

  11. The detector of BESIII,BESII and CLEOc

  12. Physics at BEPCII/BESIII • Precision measurement of CKM matrix • Precision test of Standard Model • QCD and hadron production • Light hadron spectroscopy • Charmonium physics • Search for new physics

  13. Physics to be studied in -charm region • Search for glueballs, quark-gluon hybrids and exotic states • Charmonium Spectroscopy and decay properties • Precision measurement of R • Tau physics: tau mass, tau-neutrino mass, decay properties, Lorenz structure of charged current, CP violation in tau decays … • Charm physics: including decay properties of D and Ds, fD and fDs;; charmed baryons. • Light quark spectroscopy, mc • Testing QCD, QCD technologies, CKM parameters • New Physics: rare decays, oscillations, CP violations in c- hadrons • …..

  14. Event statistics at BESIII *CLEO took 10 nb D production cross section while we took 5 nb

  15. For more detailed information and description of BESIII physics studies please refer to http://www.qwg.to.infn.it/WS-sep03/WS2talks/future/harris_BESIII.ppt

  16. Schedule • 5/2004: BESII detector was removed already • 11/2004: supporting structure/york installation • 3/2005: muon chamber installation • 5/2005: magnet installation • 10/2005: magnetic field mapping • 2/2006: EMC installation • 3/2006: MDC/TOF installation • 6/2006: Cosmic-ray run • 9/2006: BESIII detector in place • 12/2006: tuning of detector/machine

  17. Parameters and Current Status of BESIII

  18. Main drift chamber • Inner diameter: 63mm; Outer diameter: 810mm; length: 2400 mm • Inner cylinder: 1 mm Carbon fiber, outer cylinder: 10 mm CF with 8 windows • End flange: 18 mm thick Al 7075 ( 6 steps) • 7000 Signal wires : 25(3% Rhenium) mm gold-plated tungsten • 22000 Field wires: 110 mm gold-plated Aluminum • Small cell: inner---6*6 mm2, outer--- 8.2 *8.2 mm2, • Gas: He + C3H8 (60/40) • Momentum resolution (@ 1 GeV/c): • dE/dX resolution: 6-7%.

  19. -4.0 GeV/c π

  20. MDC wiring machine

  21. Optical transmission Trigger MQT Q Measurement Wire Signal Preamp dE/dx Amp + Shaper + Timing Timing VMEbus T Measurement Trigger Clock Calibration Readout Control Fan out MDC electronics DT < 0.5 ns, 0-400 ns, INL <0.5% DQ < 5fc, 15-1800 fc, INL<2% Design have been finished, several prototypes have been successfully tested

  22. EMC: CsI(Tl) crystals • 6300 crystals, (5.2x 5.2 – 6.4 x 6.4) x 28cm3 (15 X0) • PD readout, noise ~1100 ENC • Energy resolution: 2.5%@1GeV • Position resolution: 5mm@1GeV • Tiled angle: theta ~ 1-3o, phi ~ 1.5o • Minimum materials between crystals

  23. CsI Crystal production:SIC, Hammamatzu, Saint-Gobain

  24. no partition wall Mechanical support structure

  25. Assembling module of the Al-cells

  26. On crystal T/Q info. Global Buffer ÷2 10 bit ADC Local Buffer Main amplifier ×1 V M E ×16 preamp CLK Analog Sum L1 L1Reset Test, DAC Buffer full SCLK，DIN TEST Control Fan out Trigger CLK L1 CHK Baffer full EMC electronics σQ < 0.16 fc (1000 ENC) 0.5fc ～ 1500fc, 15bit Cross talk: <0.3%, INL<1% Design have been finished, several prototypes have been successfully tested

  27. Super-conducting magnet • Al stabilized NbTi/Cu conductor from Hitachi • 1.0 T, <5% non-uniformity • 921 turns, 3150A @4.5K • R = 1.475 m, L=3.52m, cold mass 3.6t • Thickness: 1.92 X0 • Inner-winding method

  28. SC magnet winding machine Suport cylinder Winding machine Windingmachine and dummy coil

  29. 图3.8.20 桶部光电倍增管的支撑环，内外两层共176个孔。 Particle ID: TOF system • 392 pieces BC408, 2.4 m long, 5cm thick • Time resolution 100-110 ps/layer • PMT: Hamamatzu R5942

  30. Beam Test：Intrinsic resolution of BC408/EJ200 Endcap：< 94 ps Barrel：< 90 ps

  31. TOF electronics • Specifications: • Time measurement : <25ps • Charge measurement: 4mv~4V, 10 bit • Fast trigger signal • System configuration: • preamplifier Bilinear Gain Stage + Fully Differential Output Stage • Frontend electronics(9U VME Boards) time/Q measurement，HPTDC based, 25 ps • Clock synchronized with the RF cavity 500MHz signal clock signal cable: Phase Stabilized Optical Fiber (PSOF) Design have been finished, several prototypes have been successfully tested

  32. m system : RPC • 9 layers, 2000 m2 • Bakelite, no linseed oil • 4cm strips, 10000 channels • Tens of prototypes (up to 1*0.6 m2 ) • Noise less than 0.2 Hz/cm2

  33. RPC production underway in the clean room

  34. VME crate PPC JTAG controller Input /output module System controller RPC L1/CLK/Reset/Check… Readout module Power supply μ counter readout Design have been finished, prototypes have been successfully tested, production ready

  35. Trigger system • Pipeline: • BEPCII in multi-bunch mode (93 )，bunch spacing: 8ns • trigegr latency: 6.4 s，events stored in pipeline buffer • No dead time due to trigger • Largely use optical fibers, FPGA, … • Event rate: • Good event rate: ~ 2000 Hz • Bhabha evt rate: ~800Hz • Cosmic-ray rate: <200Hz, rejection > 10:1 • Beam bg rate: <2000Hz, rejection > 10000:1 • Total event rate： 4000 Hz

  36. Trigger system：configuration Global Trigger Logic TOF DISC Hit/Seg Count Track Match MDC DISC Track Seg. Finder Track Finder DAQ Energy Balance EMC TrigSum TC Sum Etotal Energy L1P Cluster Counting MU DISC Mu track CLOCK RF TTC 6.4 s Design largely based on FPGA technology have been designed, prototypes underway

  37. Block Diagram of DAQ Architecture • DAQ system based on VME/PowerPC and PC farm have been designed, mini-version setup, software underway

  38. BESIII magnetic yoke and mechanics

  39. Beam background: a serious issue 1.89 GeV @ 1 Amp All Cu surfaces Total dose near the interaction region ~ 150 MeV/ms < 20 rad/year @ CsI crystals < 20 rad/year @ MDC electronics < 1 rad/year @ TOF OK for safety MDC < 20 KHz/wire TOF < 5 KHz/ch @E>500 KeV EMC < 2 KHz/ch @E>100 KeV Careful MC study has been made.

  40. Beam pipe and shielding • Be beam pipe: 30 cm long, 63mm in diameter, 2 layers • HOM power: 200W, SR: < 24 W • 20 mm Gold plating to reduce backgrounds • Liquid cooling channel between beam pipe • 20 mm Tungsten shielding

  41. Other systems • Offline computing environment based on a large scale PC farm is under study • MC based on GEANT4, first reconstruction framework released, sub-detector reconstruction code underway

  42. International collaboration IHEP, Beijing Beijing University , Beijing Tsinghua University , Beijing USTC, Hefei National Central University, Taipei KEK, Tokyo University, Tokyo Hawaii University, Honolulu Washington University, Seattle More collaborators welcomed

  43. Summary • The BEPCII/BESIII has been approved officially by the Chinese government • The BESIII detector design is finished, prototyping is successful, mass production have been started • Rich physics after CLEO-c(upgrade of BEPCII to 3*1033 cm-2s-1 is possible) • Collaborators are welcomed!

  44. Thanks

  45. Event statistics at BESIII *CLEO took 10 nb D production cross section while we took 5 nb

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