Miao He
Institute of High Energy Physics, Beijing On behalf of the Daya Bay collaboration
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Reactor Accelerator Supernova Atmosphere
Sun Earth Big Bang
Natural sources Artificial sources
neutrinos
Elementary particles in SM
3
* , 1
i i
i
U
να: weak eigenstates (νe, νμ, ντ)
νi: mass eigenstates (ν1, ν2, ν3)
Uα,i: mixing matrix (PMNS matrix) Neutrino mixing
Disappearance of reactor antineutrino: 𝝂𝒆→ 𝝂𝒆
Pee 1 sin22q13sin2 (1.27Dm2eeL/E)
6 reactor cores, 17.4 GWth
Relative measurement
2 near sites, 1 far site
Multiple detector modules
Good cosmic shielding
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amplitude frequency
The Daya Bay experiment
8 identical antineutrino
detector modules to reduce uncorrelated systematic
uncertainties
3 independent detectors (RPC+IWS+OWS) make up
muon veto system in each site
n e
e
p
Reactor electron antineutrinos are identified by the prompt- delayed signal pairs
Multiple data streams from each experiment hall (EH)
Data taking efficiency (2013)
Data taking time > 97%
Physics data taking time > 95%
Typical trigger rate
EH1: 1.3kHz
EH2: 1.0kHz
EH3: 0.6kHz
Data volume
320 raw data files per day, 1GB per file
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Online data taking monitoring of trigger rate physics run: ~48 hours/run
Pedestal run and
electronics diagnosis run EH1
EH2
EH3
Daya Bay 55 days
Daya Bay 139 days
Daya Bay 217 days
Daya Bay 621 days
sin22θ13
2012.3.8
2012.6.5
2013.8.22
2014.6.3 EH1
EH2
EH3
Start data taking in 3 halls on 2011.12.24
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IHEP/lxslc5 LBNL/pdsf
Daya Bay onsite Raw Data
Onsite data processing/PQM
Keep-Up Production
Data Quality DB DQ strip charts
at SJTU
Online DB
DCS DB
Onsite DB Offline DB
spade spade spade
Offline data monitor (ODM) at IHEP/LBNL
IHEP, Beijing in 10~15 minutes
LBNL, California in 15~20 minutes Daya Bay onsite，
in 5 minutes
Data transfer monitoring Daya Bay onsite network monitoring
Daya Bay to IHEP IHEP to LBNL
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Data storage center at LBNL
IHEP LBNL
Disk space 750TB 963TB
Harddisk file system Lustre GPFS
Tape system CASTOR HPSS
Accumulated raw data 320TB (disk), 640TB (tape) 320TB (disk), 640TB (tape)
CPU (cores) ~800 371 dedicated + additional shared
Infrastructure of data storage
Monitoring of data received/sent Monitoring of CPUs and jobs
Software framework (NuWa): Neutrino at Daya Wan
Adoption of LHCb/ATLAS Gaudi framework provides a fully developed component system for simulation, reconstruction and analysis
Extending Gaudi Transient Event Store (TES) to Archive Event Store (AES) for prompt-delayed analysis
A Lightweight Analysis Framework (LAF)
Compatible with NuWa data objects with higher I/O performance
Flexible data buffer allows to access events backwards and forwards
Multiple analysis modules running simultaneously
Bitten-slave based auto building and testing system running on multiple offline servers
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女娲
Calibration sources
Weekly calibration runs: LED, radioactive sources
Calibration samples in physics runs: PMT dark noise, spallation neutron (spn)
Calibration automation
File-by-file track (Rolling gain, spn energy scale, channel quality): automated accumulation of calibration sample and generation of calibration constants
Run-by-run track (LED gain, Co60 energy scale): semi-automation to find calibration data and generate calibration constants
Calibration constants version control
Using the rollback date of DBI: choose the latest calibration constants that were inserted into offline database before the rollback date
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Physics Performance Monitoring (PQM): quasi real-time data processing onsite using the
offline software
Raw data are processed file by file using the Portable Batch System (PBS)
16 dedicated CPU cores and 40 additional cores shared with users
Web display
Latency: ~40 minutes
Example1: Number of blocked triggers in one event vs. run time
Example2: Reconstructed energy distribution for all triggers in one AD
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A “Keep-up” production (KUP) is running at IHEP and LBNL, using the latest calibration constants and full reconstruction
Web display using an Offline Data Monitor (ODM)
Occupied computing resource: ~ 30 cores
Latency: ~ 3 hours
Multifunctional Daya Bay ODM
Example plots on ODM
Physics production (PP) uses the validated and frozen calibration constants and reconstruction algorithms.
Data volume: ~1.2 times raw data. Only keep one version on disk.
Physics production takes place 1 or 2 times per year, ~ 1 month processing time for each production
A special production strategy for the first two publications
Fix offline software, update calibration constants and extend production on the weekly basis
Weekly data production Weekly calibration
Good/bad file tagging based on auto check and manual check on data quality
Data quality strip chart: history of the detector performance
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Daily auto check Manual check and comment
Antineutrino candidate rate Energy scale stability
Daya Bay is a reactor antineutrino oscillation experiment
Daya Bay gave the first observation of the neutrino mixing angle θ13 based on the first 55 days of data
Daya Bay provided the most precision measurement of θ13 based on 621 days of data
The offline system provides quick and stable data transfer, data processing and data quality monitoring
Data Bay will continue taking data till the end of 2017. The computing resources and offline software will be upgraded to accommodate the data processing and data storage
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PRL 112, 061801 (2014)
2011.12.24 start data taking in 3 halls
2012.2.17 accumulate 55
days of data
2012.3.8 1st result of θ13
2011.12 2012.1 2012.2 2012.3 … 2012.6 … 2013.8 … 2014.6
2012.6.5 update result
2013.8.22 spectrum analysis result
CPC, 37:
011001 (2013) PRL 108,
171803 (2012)
2014.6.3 8AD result
Analysis platform
• Data transfer and storage
• Database
• Offline software
Data processing
• Detector calibration
• Event reconstruction
• Data quality
Physics analysis