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Status of BESIII Representing BES collaboration Weiguo Li IHEP, CAS liwg@ihep.ac ICHEP04

Status of BESIII Representing BES collaboration Weiguo Li IHEP, CAS liwg@ihep.ac.cn ICHEP04 Beijing, Aug. 18, 2004. BEPCII/BESIII Project BESIII Design and Current Status Schedule and Collaboration Summary. BEPCII/BESIII Project. Two rings. Covered by Zhang Chuang in this session.

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Status of BESIII Representing BES collaboration Weiguo Li IHEP, CAS liwg@ihep.ac ICHEP04

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  1. Status of BESIII Representing BES collaboration Weiguo Li IHEP, CAS liwg@ihep.ac.cn ICHEP04 Beijing, Aug. 18, 2004

  2. BEPCII/BESIII Project • BESIII Design and Current Status • Schedule and Collaboration • Summary

  3. BEPCII/BESIII Project Two rings Covered by Zhang Chuang in this session

  4. BEPCIIDesign Goals

  5. Expected Number of Events in One Year’s Running

  6. BESIII Detector 工

  7. BESIII Main Parameters

  8. Main drift chamber • Inner diameter: 63mm; Outer diameter: 810mm; length: 2400 mm;43 sense wire layers. • Inner cylinder: 1.2 mm Carbon fiber, outer cylinder: 11 mm CF with 8 windows • Outer endplate: 18 mm; stepped section 25mm; Al 7075 • 6796 Signal wires : 25 mm gold-plated tungsten • 21884 Field wires: 110 mm gold-plated Aluminum • Small cell: inner---6*6 mm2, outer--- 8.1*8.1 mm2, • Gas: He + C3H8 (60/40) • Wire resolution < 130m • Momentum resolution@1GeV: • dE/dX resolution: 6-7%.

  9. Structure and layer arrangement Blue/red Stereo wires Black:Axial: 12+7 wires

  10. 图1多层多单元漂移室模型部分丝层布局结构示意图图1多层多单元漂移室模型部分丝层布局结构示意图 Drift velocity vs field Cell structure

  11. Resolution vs Drift Distancecosmic ray Primary ionization fluctuations Distortion of field 16.4mm cell 14.0mm cell Wire resolution of 130 m is achievable; beam test done at KEK, data is being analyzed; Outer and inner cylinders are ready; Endplates are in fabrication; feed through prototypes are fine;wiring machine will be ready soon;prototype of readout electronics. Wiring will start at the end of 2004

  12. Time of Flight Counters • Barrel：2*88 scintillator bars, BC408, 2.32 m long, 5cm thick • Endcap：48+48 scintillator bars • resolution：100-110 ps/layer • PMT: Hamamatzu R5942 Barrel mechanical Endcap sideview

  13. Source of errors Barrel Time resolution Endcap time resolution One layer intrinsic time resolution 80～90ps 80-90ps Bunch time uncertainty 20ps 20ps Bunch length uncertainly 15mm，35ps 15mm，35ps MDC positioning precision 5mm,25ps 10mm,50ps Electronics 25ps 25ps Track length 30ps 30ps Time walk correction 10ps 10ps Total resolution for one layer 100～110ps 110～120ps Factors contribute to the time resolution • K/ separation: 0.8GeV.

  14. Time of Flight system • Beam test finished, intrinsic timing resolution of BC408 reached ~90ps for barrel and ~95ps for endcap, comparing with Eijen 200 scintillators • PMT tested in 1T magnetic field • Electronics using HPTDC tested, resolution ~ 18 ps • Currently under study: • reflecting materials for scintillator bars • Testing facility for mass production • PID with Aerogel Cerenkov counters • Start to order PMT and scintillator in 2005

  15. Beam Test：Intrinsic resolution of BC408 and EJ200 Barrel Endcap

  16. CsI(Tl) EMC Crystal production • 6240 crystals, (5.2x 5.2 – 6.4 x 6.4) x 28cm3 • PD readout, noise <1000 ENC at lab • Energy resolution: 2.5%@1GeV • Position resolution: 6mm@1GeV • Tiled angle: theta ~ 1-3o, phi ~ 1.5o • No wall between crystals,

  17. no partition wall Mechanical support structure

  18. Status • Crystal productions have some delay, the quality is fine, no big problems expected; • The devices for measuring crystal properties and PD are designed and are functioning • The EMC monitoring system is designed • Electronics are on schedule, <1000e at lab • The mechanical support structure is designed, prototype being tested.

  19. Crystal quality control Light output > 33% of reference crystal ~5000 e/MeV • Uniformity < 7% • Radiation hardness • Light output > 80% • after 1krad • Crystal size: • Lateral, +0 • -200m

  20. BESIII Super-conducting magnet Coil:Single layer solenoid ,steady field Cooling mode:In-direct cooling by two phase flow liquid helium Cable:Pure Al stabilized NbTi/Cu Fabrication technology:Inner winding Cold mass support:GFRP tension rod Thermal shield:Liquid Nitrogen plus multi-layer thermal insulation Flux return:Barrel/End yoke, pole tip

  21. BESIII Super-conducting magnet • SC cable • Hitachi cable Ltd., delivered • SC magnet • Collaboration with WANG NMR INC., US. • Current status • Engineer design completed • Winding machine ready • Supporting cylinder will be ready end of Aug. • Engineer design of cryogenics is nearly done • Start winding the magnet this Sep. • Magnet cooled down summer of 2005, then field • mapping

  22. m system : RPC • 9 and 8 layers, 2000 m2 • Bakelite, no linseed oil • 4cm strips, 10000 channels • Production started (endcap) • Noise less than 0.04 Hz/cm2 Covered by ZHANG Jiawen in this session

  23. Expected Performances • Solid angle: 0.89，Barrel: 0.62- 0.77 • Position resolution: 1.2 cm • Minimum momentum：0.4GeV • Efficiency: > 95% • Punch-through: <15%- a few % μ efficiency and pion punch- through rate vs momentum

  24. RPC prototypes

  25. R&D: under neutron radiation After some time for recovery, all properties back to the level almost the same as before radiation.

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

  27. 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

  28. Trigger simulation: MDC trigger Trigger System Design done, Trigger efficiency and background rejection meet the requirements Trigger boards being Designed.

  29. DAQ Systemdata transfer requirements L1 trigger rate: 4 KHz Event Size: 12 KBytes Bandwidth required after L1: 48 MByte/sec Bandwidth required on tape: 36 MByte/sec > 1000current BESII system

  30. DAQ System configuration

  31. Some tests of power pc

  32. Beam pipe and shielding • Be beam pipe: 30 cm long, 63mm in diameter, 2 layers • 10-20 m Gold plating to reduce SR backgrounds • HOM power: 200W, SR: < 24 W • Liquid cooling channel between walls • 20 mm Tungsten shielding

  33. Beam background: a serious issue 1.89 GeV @ 1 Amp All Cu surfaces

  34. Total Beam-related Backgrounds Backgrounds are simulated from - Synchrotron Radiation; - Beam-gas; - Touschek effect; - Injection. With some masks and shielding near detector Single rate Max: at MDC 40 K; TOF: 10K Dose/year at endcap EMC Max:~210rad/year, Ave:~ 50rad/year. Should be carefully monitored

  35. BESIII Offline Software System (BOSS) • A Team has been set up, most of the tasks are assigned • Completed: • Three versions of software Framework • Currently based on Gaudi • A GEANT4 based MC with all sub-detectors • Preliminary reconstruction codes with most sub-detectors • Three releases planned before end of 2006 • Need more people to work on the reconstruction and prepare for the calibration

  36. 4 π- tracks in BESIII p=0.5 -1.5GeV |cosθ|<0.9 pion punch-through Hits in end-cap TOF

  37. BESIII mechanics and return yoke • Engineer design completed • Contract for mechanics and return yoke awarded • Pre-assembly this Nov. • Start assembly next Feb. • Preparation for installation started

  38. BESIII Status • Design has been finished • Most of the R&D work successful • Detailed Budget and CPM available • Most of the budget have been contracted • Mass production has been started: • CsI Crystals • RPC muon chambers • Support structure and Yoke • Superconducting magnet • Drift chamber structure

  39. BESIII Schedule • 11/2004: supporting structure/yoke installation • 2-3/2005: endcap muon chamber installation • 5/2005: magnet installation • 10/2005: magnetic field mapping • 2/2006: EMC installation • 3/2006: MDC/TOF installation • 7/2006: BESIII debug and commissioning, Cosmic ray • 10/2006: BESIII detector in beam-line • 11/2006: commissioning detector/machine

  40. A few items are on critical path for BESIII • Mechanical support and Yoke • Mechanical support of Barrel EMC; Crystal • production • Super-conducting Magnet • Offline software • Technical Challenge • Background issues • PID, MDC, EMC performance; • DAQ system

  41. BESIII Collaboration There are about 18 Chinese institutes in BES collaboration, about 10 are actively involved in BESIII project, Physicists from US and Japan are participating in BESIII project, More foreign participants are welcome. Contact persons: liwg@ihep.ac.cn or yfwang@ihep.ac.cn

  42. Summary BESIII project is in good shape right now, We have to work hard to meet the challenges and difficulties ahead of us. I believe we should be able to complete BESIII project on time and with good quality, and start to take data in 2007.

  43. Thanks

  44. BEPCII Milestones • May. 04 – Oct. 04. : • Linac upgrade • BESII detector removed • Nov. 04 – March 05: SR running • April 05 – Jan. 06: Long shutdown • Remove existing ring • Install two rings • Cryogenics system ready for SC devices, field mapping • Feb.- Sep. 06: Tuning of machine + SR running • Oct. 06 : BESIII detector moved into beam line • Nov. 06 – Feb. 07 : Machine-detector tuning. • Physics run by March 2007

  45. Crystal production Crystal size: front：5.2cm x 5.2cm rear： 6.4cm x 6.4cm length：28cm

  46. EMC support module ( 1/60 )

  47. BESIII Main Detector Components • Small cell, He gas based drift chamber • Time of Flight Counters • CsI(Tl) crystal calorimeter • RPC muon chamber system • Super-conducting magnet of 1T

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