More%20design%20Works

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• More design Works
• More simulation to study the physics reaches
  with BESIII. magnet? solid angle coverage ?
  Identify several important physics topics, and
  study
• the physics performances.
• D physics, leptonic, semileptonic, D-Dbar
  mixing
• What is the luminosity needed after
  CLEOc,
• 1 10 to 33 or gt 3 10 to 33
• Some physics topics demand high mom.
  Resolution and very good PID

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• More study about IR, the backgrounds and mask
  design.
• More detector simulation to arrive design
  optimization
• - TOF time resolution, the z position error
  from track extrapolation?
• - the low limit of photon detection?
• Each system (detector components, DAQ and
  electronics) needs RD, prototypes
• Commissioning machine with detector outside beam
  line, radiation issue.

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• Major issues related with BESIII design
• The radius of crystal calorimeter, affecting
  performances and cost. Possibility of using CsI
  crystals as EMC.
• Personally, CsI is fine, except radius
  problem, if we use existing magnet (CLEO I)
• Backgrounds associated with machine operation,
  the design of interaction regions, vacuum, masks,
  etc.

Experienced man power big issue
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Competition from CLEOC Serious challenge from
CLEOC project Design machine and detector to be
as advanced as possible, Complete the
BEPCII/BESIII project ASAP Collaboration between
BES and CLEO

• Fit with BEPCII lattice, space? 1.8 m from IP to
  SCQ
• Schedule, commitment of detector moving?
• - Physics collaboration?

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BESIII Collaboration Welcome international
collaboration, and domestic collaboration,
groups to participate in BESIII project Design,
MC simulation, decision making process for
making Final decision, Sub-detectors RD
and construction Electronics RD and
manufacture Online/Offline software, more
flexible arrangement Software
package Reconstructions and
Calibration code Physics study
In charge of some sub-system or send people to
IHEP
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• about Cost and schedule
• Cost for EMC, SC magnet and electronics is most
  crucial
• MDC, EMC and SC magnet (including iron
  structure) on critical path.
• Man power issues
• Serious man power shortage exists, especially
  the experienced people.

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• Cost estimation of Detector subsystem
  (Preliminary)
• In M RMB (1 USD 8.3 RMB)
• Beam pipe vertex chamber
  3.0
• MDC
  11.0
• TOF
  6.0
• Barrel EMC
  54.0
• Endcap EMC
  20.0
• Barrel Muon detector
  4.5
• Endcap Muon detector
  2.5
• Super conducting magnet
  45.0?
• Luminosity
  2.0
• Electronics
  63.0?
• Trigger and DAQ
  13.0
• Total
  224.0
• about 1/4 to 1/3 of the detector budget
  either be contributed other sources
• or be staged.

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Schedule

• Feasibility Study Report of BEPC II has been
  submitted to the funding agency .
• Technical Design Report of BEPC II to be
  submitted by first half of 2002.
• Construction started from Summer of 2002
• BESII detector moved away Summer of 2004, and the
  BESIII iron yoke started to be assembled, mapping
  magnet early 2005
• Preliminary date of the machine long shutdown
  for installation Spring of 2005
• Tuning of Machine Beginning of 2006
• BESIII detector moved to beam line, May 2006
• Machine-detector tuning, test run at end of 2006

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Schematic of BESIII detector
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Major Upgrades in BESIII

• Superconducting magnet
• Calorimeter BGO with ?E/E 2.5 _at_ 1GeV
• MDC IV with small cell, Al wires and He gas
• Vertex detector Scintillation fibers for
  trigger
• Time-of-flight ?T 65 ps
• Muon detector
• New trigger and DAQ system
• New readout electronics

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Scintillating fiber for Trigger

• 1.27 mm or thinner Be beam pipe may be used
• R 3.5 cm
• 2 double-layers one axis layer and one stereo
  layer
• Scintillating fiber 0.30.3 mm2, L60 cm
• Clear fibers 0.30.3 mm2, L1.4 m
• two side readout by APD (F3) (below 300)
• Signal/noise lt6 p.e.gt / lt1p.e.gt
• ?? 50 ?m ?z 1mm
• Total of channels 27 x 8 216

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Main Draft Chamber

• End-plates with stepped shape to provide space
  for SC quards and reduce background
• Inner part stepped conical shape, cos ? 0.93
• Outer part L 190 cm, cos? 0.83 with full
  tracking volume
• cell size 1.4 cm x 1.4 cm
• Number of layers (cell in R) 36
• Gas HeC2H6 , or HeC3H8
• Sense wire 30 ?m gold-plated W ,
• Field wire 110 ?m gold-plated Al
• Single wire resolution 130 ?m
• Mom. resolution 0.8 _at_ 1GeV 1T, 0.67
  _at_1GeV1.2T
• DE/dx resolution 7

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Trackerr simulation of MDC, ?pt as a function of
pt in for pion, wire resolution 130 ? m
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Trackerr simulation of MDC, ?pt as a function of
pt in for pion, wire resolution 100 ? m
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PID Time of Flight Counters

• Double layers TOF ( or TOF CCT)
• plastic scintillator (BC-404)
• 80 pieces per layer in ?
• R 66 75 cm,
• Thickness 4 cm, length 190 cm
• Readout both sides by F-PMT
• Time Resolution 65 ps
• 2son k/? separation
• 1.11.5GeV/c (for polar angle 00 450)
• For CCT option, need RD

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TOFTOF
TOFCCT
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BGO Barrel Calorimeter

• To provide minimum space for main draft chamber
  and TOF and to obtain the necessary solid angle,
  one must modify L3 BGO crystals, and add new
  crystals
• 13 X0 ?E/E 2.5 _at_ 1GeV
• Rin 75cm , Lin 200cm cos ? 0.83
• Cut L3 BGO crystals (10752) 22 X0 (24cm)
  into 13X0 (14cm) 8.5 X0(9.5cm)
• Making new bars of 14 cm
• by gluing 9.5cm new crystal of 4.5cm
• new BGO crystals needed.  

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• Endcap Detector
• Two possible technologies can be used,
• CsI crystals as in the detector figure, similar
  technology as in the barrel, need endcap TOF.
• 2. Similar technique as KLOE using lead-fiber
• technique, may not need TOF counters.
• The first choice is preferred.

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Superconducting Magnet for BESIII

• B 1 1.2 T,
• L 3.2 m
• Rin 105 cm, Rout 145 cm
• Technically quite demanding for IHEP,no
• experience before, need collaboration from
• abroad and other institutes in China, both for
• coil and cryogenic system.

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Muon Counter

• Barrel (L 3.6m ) Endcap cos? 0.9
• Consist of 12 layers stream tube or RPC
• Rin 145cm (yoke thickness 40cm)
• Iron plate thickness 2-6 cm
• ? counter thickness 1.5 cm
• Readout hits on strips 3cm
• total weight of iron 400 tons

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Muon acceptance
Pion contamination
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• Interaction Region
• It is very compact at IR, very close cooperation
  is needed in the designs of detector and machine
  components at IR
• Understand the space sharing, the support,
  vacuum tight
• Understand the backgrounds from machine and how
  to reduce them,
• - Beam loss calculation (masks)
• - Synchrotron radiation (masks)
• - Heating effect (cooling if necessary)
• Understand the effects of the fringe field from
  SCQ to the detector performances

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• Luminosity Monitor
• Because the situation at the IR, the luminosity
  has to either
• be located quite far away from the IR (3-5m), or
  in front of
• Machine Q magnet, to be designed carefully.
• Accurate position determination
• Multiple detection elements at each side to
  reduce the
• variation of luminosity when the beam position
  shifted
• BGO crystals ?

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• Trigger
• Trigger rate estimation
  (using the same
  trigger conditions as now)
• Background rate, with 40 times beam current and
  half of the beam lifetime, the rough estimation
  for the background is 80 times the current rate
  (10-15), or 800-1200 Hz, taking 1500 as a design
  number
• Good event rate

When leave room for maximum luminosity to be as
calculated, 1?1033, 200 times as current event
rate, to be 1500 Hz

• Cosmic ray background can almost be negligible

Total peak trigger rate can be more than 3000 Hz,
additional trigger (software) is needed to reduce
the event rate to 2000Hz.
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Level 0 and 1 are hardware triggers, latency
2.4?s, Level2 is software filtering using
online computing farm Because fastest detector
element TOF need a time window of about 30 ns,
the trigger can identify bunch train only, not
individual bunch

• Level 0 with TOF signals
• Level 1 with hardware track finding, EMC
  clustering, total EMC energy, VC tracking or
  hits, ? counter hits

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• Front-end Electronics
• Pipeline scheme is required
• Requirements
• For the timing measurement
• 25 ps for TOF, 0.5 ns for MDC
• For charge measurement
• 1 accuracy for EMC, 2 for MDC and TOF
• Total number of electronic channels 76800 (too
  many muon channels?)

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Data Acquisition System Event builder 3000 Hz ? 6
K bytes 20 Mb/s Event filtering Data
storage Run control Online event monitor Slow
control
Switch network
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• Offline Computing and Analyses Software
• Computing, network, data storage, data base,
  processing management
• Supporting software package, data offline
  calibration, event reconstruction, event
  generators, detector simulation

Total CPU 36000 MIPS Data storage 500 Tbytes/y
on tapes, 24 Tbytes/y on disks Bandwidth for data
transfer 100 Mbps
Substantial manpower needed for software
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Major New Subsystems of BESIII

• Vertex chamber ZHANG
  Qinjian
• Main drift chamber CHEN
  Yuanbo
• Time of flight counter HENG
  Yuekun
• EMC shower counter LU
  Jungguang
• Luminosity monitor WU Jian
  (USTC)
• Trigger system LIU
  Zhenan
• Front-end electronics SHENG Huiyi, ZHAO,
  Jingwei
• Data Acquisition HE
  Kanglin
• Computing and software MAO Zepu

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• Detector RD
• A lot of new detector technology
• RD for most sub-systems started
• Detector optimization is needed
• Modify the detector design when international
  collaboration is formed, new ideas are mostly
  welcome

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Cost Estimation

• Detector 220M Chinese Yuan ( 30 M US )
• 2/3 to 3/4 are from Chinese Government
• International collaboration and contribution
  are needed

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Intl. Cooperation on BEPC II / BES III

• Intl. cooperation played key role in design,
  construction and running of BEPC/BES.
• Intl. cooperation will play key role again in
  BEPC II / BES III design, review, key
  technology, installation, tuning
• Participation of foreign groups is mostly
  welcomed.
• BESIII should be an international
  collaboration,
• Establish organization accordingly.

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If not enough fund is expected, 2nd option
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• Summary
• BEPC energy region is rich of physics, a lot of
  important physics results are expected to be
  produced from BESIII at BEPCII
• Detector design is started, need a lot of
  detailed work to finish detector design
• Very interesting and very challenging project

Thanks