???, IHEP

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• ???, IHEP
• On behalf of
• ??????
• DAQIHEP

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sin22q13 Measurement at reactors
Well understood, isotropic source of electron
anti-neutrinos
Detectors are located underground to shield
against cosmic rays.
1.0
Unoscillated flux observed here
Probability ?e
Distance (L)
1500 meters
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Dayabay Reactor Neutrino Experiment
900 m
465 m
607 m
810 m
292 m
Total Tunnel length 3000 m
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Detecting ??e

• Inverse ?-decay in 0.1 Gd-doped liquid
  scintillator
• Antineutrino signal, algorithm implemented in
  offline or on online computer farm
• Time coincidence
• Energy correlated

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Requirements of readout electronics

• Readout board designed for all detector systems
  except RPC.
• Neutrino detector
• Charge measurement
• Dynamic range for each PMT 0 PE -- 500 PE
• 50 p.e is the maximum for a neutrino event
• 500 p.e. for through-going muons
• resolution lt10 _at_ 1 p.e, 0.025_at_ 400 p.e.
• Noise lt 0.1 p.e.
• Digitization time(mainly shaping time) lt 1 ms
• Timing measurement
• To determine event time and event vertex
• dynamic range 0 500 ns
• resolution lt 500 ps
• Muon detector
• Water pool Same requirements as neutrino
  detector
• Water Tracker Hit and/or charge
• RPC BESIII electronics

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Readout board diagram
On board calibration circuit
TDC algorithm Gray counters
16 Channel inputs
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Trigger requirement

• Good background rejection power
• rate can go to KHz
• rate limited by DAQ capabilities
  (hopefully lt 10 MB/s/module)
• Low threshold ( T3s lt 1MeV )
• Record prompt positron signals and delayed
  signals from the neutrino interactions.
• Record the background to enable background
  analysis.
• High and well known efficiency
• Flexibility (to fight backgrounds), same trigger
  board for different detector.
• FPGA
• Daughter card
• Reliability (to reduce systematic errors)
• Independency, Separate trigger for each of
  neutrino module, and each of muon detector, water
  pool, water cenrenkov module and RPC.
• Redundancy (to measure the trigger efficiency)
• Provide a system clock

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Algorithms

• Central trigger OR of the following two
• Energy total charge gt 15 PE
• Multiplicity gt 15 PMT fired
• Veto trigger OR of the following two
• RPC gt two hits in any plane (Scin. gt 1 hits )
• Water gt few PMT fired
• Prompt and delayed sub-event triggered and
  recorded independently, time correlation offline
• Central and veto events triggered and recorded
  independently, time correlation offline
• No dead-time induced. Trigger rate is limited by
  electronics recover time and by DAQ bandwidth.
• Trigger type
• Primary physics trigger
• LED
• Radioactive source
• Periodic trigger
• Muon trigger

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PMT dark current rate

• PMT max. number 200
• PMT dark current rate50k
• Integration windows100ns

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Trigger rate
Detector Event Trigger Rate Trigger Rate Trigger Rate Occ. Ch size (bits)
Detector Event DB LA Far Occ. Ch size (bits)
??e Module Cosmic-µ 36x2 22x2 1.2x4 100 22464
??e Module Rad. 50x2 50x2 50x4 100 22464
Pool Cosmic-µ 250 160 13.6 50 340(252)64
Tracker Cosmic-µ 1390 819 57.8 100 864
RPC Cosmic-µ 260 260 415 10 7650(5040)1
RPC Rad.Noise 186 117 10.5 10 7650(5040)1
Site totals kB/s 653 483 419 1555 1555
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Trigger board

• One board per module
• Same hardware design for central and veto board
• Each trigger board can handle up to 256 PMTs
• Decision time ? Readout event buffer depth
• Multiplicity trigger based on FPGA 200 ns
• Energy trigger based on total charge 300 ns ?
  
• System clock Local clock

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Trigger scheme
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Timing

• Each site has a master clock to synchronize the
  veto and central modules
• A GPS time/1 PPS/10 kHz reference will be
  delivered to each site for an absolute time stamp
• If GPS can not be used, we can use a local clock,
  a problem for Supernova studies.
• Precision GPS time 100 ns. Time-stamp
  precision level 25ns.
• Each trigger board have a local clock for self
  trigger and testing.

Mid-site
DYB
LA
FAR
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DAQ block diagram
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Data acquisition online control

• VME based front-end hardware, Motorola PowerPC
  controller
• RT-Linux RTOS TimeSys Co. LinuxLink
• Back-end Linux PC. Software based on
  BES-III/Atlas Framework
• Each detector system and each neutrino module at
  each site is readout (trigger) independently.
• 8 antineutrino streams and 9 muon streams. Event
  reassembled using timestamp offline.
• One neutrino module ? One VME crate.
• Water pool ? One VME crate (near), Two VME crates
  (far).
• Water Cerenkov Module system TWO VME crates.
• Communication
• Copper between trigger-FEE
• Twisted cable between PowerPC and readout
  computer
• Optical between site-site/site-surface.

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Data acquisition and online control

• Online control
• Local online control in each detector hall each
  detector system has its own online control.
  Detector debugging and commissioning in parallel.
• Global online control in surface room Operate
  and monitor all detector system.
• Data storage
• Data throughout 1.5MB/s. ? 0.4TB/day (safety
  factor of 3).
• Local tapes
• Local disks
• Data transfer
• Tapes from DYB to IHEP or to Shenzhen Uni.
• A data link from Shenzhen Uni. to IHEP via
  network can be discussed
• A data center at IHEP to be established. Raw data
  or processed data tapes will be copied and
  shipped to other data centers in the world, or
  distributed via GRID.

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One Readout VME crate
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Status

• Simple version of readout boards and trigger
  board are successfully running on the prototype.
• We are working on the 2nd version of readout
  board and trigger board
• We finished conceptual design of DAQ
• DAQ group is formed and begin to work on the
  project