Online Reconstruction

Online Reconstruction

• Linda R. Coney

• 5 November 2009

Online Reconstruction

• G4MICE uses the unpacker to look at data from DATE

• It then converts the raw data into information with physical meaning

• Goal:

• Provide a fixed set of histograms to be filled during data taking
• These histograms will contain quantities that can give information about the physics happening – a first look at analysis quantities
• Provides another data quality check
• Are we taking the data we think we are?
• Are the detectors & beam behaving as planned?
• Provide graphical interface to display plots
• Provide comparison plots for shifters

• Not meant to be final results

• Collaboration chooses list of useful histograms

• Preliminary list follows

Online Reconstruction Histograms

• Step I

• TOF

• # planes hit/event
• # slabs hit/event
• Pulse heights
• Distribution in x, y across TOF0, TOF1, TOF2
• 2D x vs y  gives shape of beam
• Reconstructed time-of-flight
• Momentum if assume  etc
• dt (plane 1 vs plane2) in TOF0, TOF1, TOF2
• 2D x vs y  gives shape of beam
• RF phase calculated vs absolute time in spill

• CKOV

• Light yield in CKOVA and in CKOVB
• Construct some CKOV measure using the two CKOVs

• KL ???

• PID determination

• CKOV A B light yield vs TOF
• TOF vs PTracker
• Check x,y in TOF1 vs x,y in the tracker at input and similarly at the other end of the channel for TOF2 and tracker2

Online Reconstruction Histograms

• Step II & Beyond

• Tracker(s)

• # planes hit/event
• # stations hit
• Pulse heights
• # points used in online reconstruction
• Muon px, py, pz, pT, p at the 2 tracker reference planes
• x,x’, y,y’
• 1D, 2D plots of position at 2 tracker reference planes
• Light yield distributions for each station

• PID determination

• CKOV A B light yield vs TOF
• TOF vs PTracker
• Check x,y in TOF1 vs x,y in Tracker1 at input and same for TOF2 and exit of Tracker2

• EMR ???

Online Reconstruction Histograms

• Step I & Beyond

• Beam emittance, amplitude

• Beamline 2D plots (x, x’) & (y,y’)
• x,y
• x’,x
• y’,y
• x, y
• momentum
• MICE Step III and IV – energy in Tracker1 vs energy in Tracker2 and DE
• MICE Step V and VI
• DE vs RF phase
• DE vs absolute time

Online Reconstruction Histograms

• What is needed to produce these plots?

• Online Reconstruction farm

• G4MICE installed on farm

• TOF reconstruction

• CKOV reconstruction

• Tracker reconstruction

• KL reconstruction

• EMR reconstruction

• Calibration for all detectors

• Unpacking code for each detector

• Check that G4MICE uses unpacker in a same way that Online Monitoring uses unpacker

Current Status of Reconstruction

• TOF Reconstruction and calibration well underway

• CKOV reco same

• Tracker reconstruction works

Online Reconstruction Farm

• Installed two farm computers in MICE control room March 09

• MICEOnRec01a
• MICEOnRec01b
• MICEOnRec02a
• MICEOnRec02b

• Total of three quad-core processors

• G4MICE installed on both

• Tests run

• Reconstructed tracker cosmic ray test data
• 114 events/second
• Ran simulation, digitization, and reconstruction of Step VI
• Simulation: ~262 events/second
• Simulation + Digi: ~236 events/second
• Reconstruction: ~1920 events/second

Online Reconstruction Histograms

• What is needed to produce these plots?

• Online Reconstruction farm 

• G4MICE installed on farm 

• TOF reconstruction 

• CKOV reco 

• Tracker reco 

• KL reco ?

• EMR reco (later)

• Unpacking code for each detector

• TOF, CKOV, GVA, KL 
• Trackers, EMR (late 2009)

• Check that G4MICE uses unpacker in same way that Online Monitoring uses unpacker

• Can produce online monitoring plots with G4MICE 
• Testing under way to compare to standard Online Monitoring plots (11/09)

Online Reconstruction

• Read data

• Questions: Read from socket (as Online Monitoring) or from data file?
• Issues: How read socket data? Will it affect DAQ?

• Process data

• Use only released version of reconstruction software
• Online Reco in CVS
• Offline reconstruction code used to process data but then histograms specific to Online Reco will be produced
• Initial version of this code exists thanks to Mark Rayner
• Application: OnlineReconstruction
• Iterative process – initial version only has TOF information

• Create plots

• Use Root – Parallel processing on the different online reco computers
• PROOF determined to be good way to accomplish this – Paul Kyberd

• Save data – Henry Nebrensky

• Online Reco root files will be saved along with the run data and the Online Monitoring files
• OnRec.####.root

Online Reconstruction Questions

• Do we need absolute real-time information? Is one-file delay a problem?

• Which calibration to use?

• Whatever is in the release.

• How many plots do we want?

• Corrolary: What is the processing overload?

• Ntuples with the ability to play randomly with the data is not intended.

• Do we use already existing beamline design tools (ex. Chris Rogers)?

• Will it be done by the end of November?

• No. We will have a simplified version to show that the method works and will produce TOF plots.
• Iterative process – add more as more reconstruction capability exists.

• ad

Conclusions

• Now:

• Read out and decode DATE DAQ from MICE beam data
• Can reconstruct TOF, CKOV, Tracker data
• Initial version of Online Reco Application exists
• Parallel processing solution found: PROOF

• Next:

• Implement online reconstruction for Step I
• Goal to see first plots in MLCR by end November
• Can practice with old data
• Start with TOFs and CKOV
• Gather more requests for Online Reco plots

• Eventually:

• Include necessary information for further steps
• Routinely have shifters monitoring detectors and MICE physics in MLCR

MICE Online

• So far:

• DAQ front end
• Trigger
• Event Building
• Controls and Monitoring

• Given that we are successfully running the experiment and creating data

• How do we know the equipment is working well?
• How do we check the data quality?

• Two levels of real-time data quality checks

• Online Monitoring
• Look at raw data for each board in the DAQ
• No translation into physical quantities
• Online Reconstruction
• Initial look at analysis variables and detector information with geometry

• Next: see Data Flow MICE notes 252 & 255