Status of BESIII Representing BES collaborationWeiguo LiIHEP, [email protected], Aug. 18, 2004
BEPCII/BESIII ProjectBESIII Design and Current StatusSchedule and CollaborationSummary
BEPCII/BESIII Project Covered by Zhang Chuang in this sessionTwo rings
BEPCII Design Goals
Beam energy
1 2.1 GeV
Optimal energy
1.89 GeV
Luminosity
1 x 10 33 cm-2s-1 @ 1.89 GeV
Linac requirements
Full energy injection: 1.55 1.89 GeV
Positron injection rate > 50 mA/min
Dedicated SR
250 mA @ 2.5 GeV
Expected Number of Events in One Years Running
Physics Channel C. M. Energy (GeV) Peak Lumi. (1033cm-2s-1) Cross Section(nb) Events per Year J/3.0970.6~3400101093.6701.0~2.4121063.6861.0~6403.0109D3.7701.0~525106Ds4.0300.6~0.321.0106Ds4.1400.6~0.672.0106
BESIII Detector
BESIII Main Parameters
systemBES III XY = 130 mMDCP/P = 0.5 %(1 GeV) dE/dx = 6-7 %EMCE/E = 2.5 %(1 GeV) z,= 5-6mm (1 GeV)TOFT = 90-100 ps Barrel 110 ps endcap counter9- 8 layersMagnet 1.0 tesla
Main drift chamberInner 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 windowsOuter 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 < 130mMomentum resolution@1GeV:
dE/dX resolution: 6-7%.
Blue/red Stereo wiresBlack:Axial: 12+7 wiresStructure and layer arrangement
Cell structureDrift velocity vs field
3
2.332.322.442.34
0.9240.9242.682.59
2.792.842.92.83
1.2071.2072.982.89
2.9433.082.99
1.4191.4193.163.07
3.093.163.223.13
1.7371.7373.373.31
3.381.9553.473.4
2.232.233.583.52
3.532.4063.633.57
2.732.733.73.65
3.683.0083.743.7
3.363.363.773.75
3.793.5343.5343.76
4.5C
28.5C
28.5C
4.5C
4.5C
28.5C
E/P(V/cmTorr)
(cm/s)
Sheet1
0.7522.332.342.322.44
0.9242.592.68
1.1282.792.832.842.9
1.2072.892.98
1.3162.942.9933.08
1.4193.073.16
1.5043.093.133.163.22
1.7373.313.37
1.9553.383.43.47
2.233.523.58
2.4063.533.573.63
2.733.653.7
3.0083.683.73.74
3.363.753.77
3.5343.793.76
Sheet1
4.5C
28.5C
28.5C
4.5C
4.5C
28.5C
E/P(V/cmTorr)
(cm/s)
Sheet2
Sheet3
Resolution vs Drift Distancecosmic ray16.4mm cell 14.0mm cell Primary ionization fluctuationsDistortion of fieldWire 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
Time of Flight CountersBarrel2*88 scintillator bars, BC408, 2.32 m long, 5cm thickEndcap48+48 scintillator barsresolution100-110 ps/layerPMT: Hamamatzu R5942Endcap sideviewBarrel mechanical
K/ separation: 0.8GeV.Factors contribute to the time resolution
Time of Flight systemBeam test finished, intrinsic timing resolution of BC408 reached ~90ps for barrel and ~95ps for endcap, comparing with Eijen 200 scintillatorsPMT tested in 1T magnetic field Electronics using HPTDC tested, resolution ~ 18 ps Currently under study:reflecting materials for scintillator barsTesting facility for mass productionPID with Aerogel Cerenkov countersStart to order PMT and scintillator in 2005
Beam TestIntrinsic resolution of BC408 and EJ200 BarrelEndcap
no partition wall Mechanical support structure
Light output > 33% of reference crystal~5000 e/MeVUniformity < 7%Radiation hardness Light output > 80% after 1kradCrystal size: Lateral, +0 -200mCrystal quality control
BESIII Super-conducting magnetCoil: Single layer solenoid ,steady fieldCooling mode: In-direct cooling by two phase flow liquid helium Cable: Pure Al stabilized NbTi/CuFabrication technology:Inner windingCold mass support: GFRP tension rodThermal shield: Liquid Nitrogen plus multi-layer thermal insulationFlux return: Barrel/End yoke, pole tip
Cryostat Inner radius1.375m Outer radius1.7m Length3.91mCoil Mean radius1.485m Length3.52mCable dimension3.7mm*20mmElectrical parameters Central field1.0T Nominal current3250A Inductance2.1HStored energy9.5MJCold mass3.6tonTotal Weight14.6tonRadiation thickness2X0
BESIII Super-conducting magnetSC cableHitachi cable Ltd., deliveredSC magnetCollaboration with WANG NMR INC., US. Current status Engineer design completedWinding machine readySupporting cylinder will be ready end of Aug. Engineer design of cryogenics is nearly doneStart winding the magnet this Sep. Magnet cooled down summer of 2005, then field mapping
m system : RPC9 and 8 layers, 2000 m2Bakelite, no linseed oil 4cm strips, 10000 channelsProduction started (endcap)Noise less than 0.04 Hz/cm2
Covered by ZHANG Jiawen in this session
RPC prototypes
R&D: under neutron radiationAfter some time for recovery, all properties back to the level almost the same as before radiation.
Trigger system Event rate: Good event rate: ~ 2000 HzBhabha event rate: ~800HzCosmic-ray rate: 10:1Beam background rate: 10000:1Total event rate 4000 HzPipeline: BEPCII in multi-bunch mode ( 93 )bunch spacing: 8ns trigger latency: 6.4 sevents stored in pipeline buffer No dead time due to triggerLargely use optical fibers, FPGA,
Trigger systemconfigurationGlobal Trigger Logic6.4 sTOFMDCEMCMUDISCDISCMu trackDISCTrigSumTrack FinderEtotal EnergyHit/Seg CountTrack Seg. FinderDAQRFTTCTC SumL1PCLOCKTrack MatchEnergy BalanceCluster Counting
Trigger simulation: MDC triggerTrigger SystemDesign done,Trigger efficiency and background rejection meet the requirementsTrigger boards being Designed.
DAQ Systemdata transfer requirementsL1 trigger rate: 4 KHz Event Size: 12 KBytesBandwidth required after L1: 48 MByte/secBandwidth required on tape: 36 MByte/sec> 1000 current BESII system
DAQ Systemconfiguration
File Server
Online Farm PCs
1 Gbps Switch
Run Control
Histogram Display
Event Display
Fast EthernetSwitch
FarmSupervisor
...
MDC
Fast Ethernet
VME Crates (16)
Readout PCs (4)
TOF
Fast Ethernet
VME Crates (2)
Readout PC (1)
EMC
Fast Ethernet
VME Crates (16)
Readout PCs (4)
MUC
Fast Ethernet
VME Crates (4)
Readout PC (1)
TRG
Fast Ethernet
VME Crates (10)
Readout PCs (2)
Some tests of power pc
Chart1
0.24533333310.13199999950.24466666650.0839999982
0.14266666660.13233333280.12633333310.0756666668
0.13799999970.13233333320.10383333280.0716666666
0.13633333330.13233333320.08833333320.0681666665
0.13654166660.13233333320.08320833330.0678749999
Ttotal(opt=1)
Ttotal(opt=0)
Tcpu(opt=1)
Tcpu(opt=0)
Event Num
Time(s)
Sheet1
NevtOnet(opt=1)Onet(opt=0)Ttotal(opt=1)Ttotal(opt=0)Tcpu(opt=1)Tcpu(opt=0)Oidl(opt=1)Oidl(opt=0)
16.1333333283.2999999880.24533333310.13199999950.24466666650.08399999820.0166666661.200000032
27.1333333286.6166666420.14266666660.13233333280.12633333310.07566666680.8166666742.8333333
413.79999996813.2333333240.13799999970.13233333320.10383333280.07166666663.416666696.066666664
827.26666665626.4666666480.13633333330.13233333320.08833333320.06816666659.60000001612.83333334
1654.61666664252.9333332960.13654166660.13233333320.08320833330.067874999921.3333333225.783333342
Chart2
0.0360.1520.056
0.0340.1480.054
0.0340.1470.054
0.0340.14750.0545
0.033750.148750.05425
Tcpu(notbl)
Tcpu(tbl)
Tcpu(GEO)
Event Num
Time(s)
Tpack
Sheet2
NevtOcpu(notbl)usOcpu(GEO)usOcpu(tbl)usTcpu(notbl)sTcpu(GEO)sTcpu(tbl)s
1914380.0360.0560.152
21727740.0340.0540.148
434541470.0340.0540.147
8681092950.0340.05450.1475
161352175950.033750.054250.14875
Chart3
0.1760.2920.0360.1520.0840.056
0.137670.251670.0340.1480.075670.028
0.119670.232670.0340.1470.071670.014
0.109170.222670.0340.14750.068170.007
0.105130.220130.033750.148750.067880.0035
Total (no Calibration)
Total (Calibration)
EB (no Calibration)
EB (Calibration)
Network Transfer
DMA Transfer
Number of Events / Interrupt
Time (s)
The CPU Usage
Sheet3
NevtTnet(opt=0)Tpack(notbl)TdmaTpack(tbl)T(opt=0,notbl)T(opt=0,tbl)
10.0840.0360.0560.1520.1760.292
20.075670.0340.0280.1480.137670.25167
40.071670.0340.0140.1470.119670.23267
80.068170.0340.0070.14750.109170.22267
160.067880.033750.00350.148750.105130.22013
Beam pipe and shieldingBe beam pipe: 30 cm long, 63mm in diameter, 2 layers10-20 m Gold plating to reduce SR backgroundsHOM power: 200W, SR: < 24 WLiquid cooling channel between walls20 mm Tungsten shielding
Beam background: a serious issue1.89 GeV @ 1 AmpAll Cu surfaces
Total Beam-related BackgroundsBackgrounds are simulated from - Synchrotron Radiation; - Beam-gas; - Touschek effect; - Injection.With some masks and shielding near detectorSingle rate Max: at MDC 40 K; TOF: 10KDose/year at endcap EMC Max:~210rad/year, Ave:~ 50rad/year.Should be carefully monitored
BESIII Offline Software System (BOSS) A Team has been set up, most of the tasks are assignedCompleted:Three versions of software FrameworkCurrently based on GaudiA GEANT4 based MC with all sub-detectorsPreliminary reconstruction codes with most sub-detectorsThree releases planned before end of 2006Need more people to work on the reconstruction and prepare for the calibration
BESIII mechanics and return yoke
Engineer design completedContract for mechanics and return yoke awarded Pre-assembly this Nov.Start assembly next Feb.Preparation for installation started
BESIII StatusDesign has been finishedMost of the R&D work successfulDetailed Budget and CPM available Most of the budget have been contractedMass production has been started:CsI CrystalsRPC muon chambersSupport structure and YokeSuperconducting magnetDrift chamber structure
BESIII Schedule11/2004: supporting structure/yoke installation2-3/2005: endcap muon chamber installation5/2005: magnet installation10/2005: magnetic field mapping2/2006: EMC installation3/2006: MDC/TOF installation7/2006: BESIII debug and commissioning, Cosmic ray10/2006: BESIII detector in beam-line11/2006: commissioning detector/machine
A few items are on critical path for BESIII Mechanical support and Yoke Mechanical support of Barrel EMC; Crystal production Super-conducting Magnet Offline softwareTechnical Challenge Background issues PID, MDC, EMC performance; DAQ system
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:[email protected] or [email protected]
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.
Thanks
BEPCII MilestonesMay. 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 ringsCryogenics system ready for SC devices, field mappingFeb.- Sep. 06: Tuning of machine + SR running Oct. 06 : BESIII detector moved into beam lineNov. 06 Feb. 07 : Machine-detector tuning. Physics run by March 2007
Crystal size:front5.2cm x 5.2cm rear 6.4cm x 6.4cm length28cmCrystal production
QuantitySaint-Gobain3000SIC1920Hamamatzu1320
EMC support module ( 1/60 )
BESIII Main Detector ComponentsSmall cell, He gas based drift chamberTime of Flight CountersCsI(Tl) crystal calorimeterRPC muon chamber system Super-conducting magnet of 1T
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