Hit Finder Validation & Prospects for Purity Measurement - - PowerPoint PPT Presentation

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Hit Finder Validation & Prospects for Purity Measurement

Matthew Thiesse 7 September 2016 35-ton Sim/Reco Meeting

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Overview

• Recent progress has been good, some interesting plots

ahead

• The priority to fjnd a “good event” list has been

narrowed to fjnding a “good wire” list since the levels of signal and noise vary so much over time and throughout the detector

• MC studies have shown what should be possible from

the hit reconstruction, does it still apply for real data??? Is calorimetric measurement even possible?

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Code changes

• Committed new reconstruction fhicl fjles and new Hit Reconstruction module:

– dune/HitFinderDUNE/RobustHitFinder_module.cc – dune/fcl/dune35t/reco/standard_reco_dune35tdata_robusthit.fcl – dune/fcl/dune35t/reco/standard_reco_dune35tsim_robusthit.fcl

• Fixed some existing muon counter code:

– dune/DetSim/SimCounter35t_module.cc

• Now gives accurate timing information

– dune/T0Reco/t0reco.fcl

• Use @local::dune35t_t0counter for real data
• Use @local::dune35t_t0countersim for simulated data
• Not sure if people are using T0Counter_module.cc to fjnd counter coincidences and

anab::T0 objects, but you should! It works!

– Now works for simulation too, with the appropriate fhicl tag

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Last week

• Validating RobustHitFinder
• For real data, situation looks

bleak

• Red line ---->

– Essentially hit fjnding

effjciency vs. drift distance

– Should be a fmat line – hit

fjnding effjciency should not depend on drift distance

– i.e. the hit fjnding threshold

should be low enough that even the lowest charge hits are recorded

Drift distance (cm)

Red Line: Average number of hits per event. Divide this by number of good wires to get an efficiency.

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MC Study

• Did MCC-scale simulation of
• pposite-counter East-west

muons

• Test RobustHitFinder

“effjciency”

• Using threshold of 2*RMS,

no loss of hit-fjnding effjciency with drift distance was observed.

• Simulated noise: 2.5ADC
• e- lifetime: 3ms
• 336 total collection plane wires possible

for track parallel to APA

• Roughly 290 wires not already ignored by

channelstatus_dune.fcl

• So, divide 315-ish (red points) by 290 is

better than 100% effjciency

• This means more than one hit is recorded

per event per wire on average (deltas)

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MC Study

• Need to confjrm that it is consistent
• n a channel-by-channel basis since

the threshold is determined on a channel-by-channel basis

• I apologize for the messy plot, need

to fjnd a better way to present this info…

• Each line represents the same thing

as the red lines in slides 4 and 5, except one black line per channel

• Confjrms expectation: no loss of

effjciency with drift distance, all wires have more-or-less fmat effjciency.

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MC Study

• What if the hit fjnding

threshold changes? Or equivalently, the signal-to-noise is reduced?

• Make an artifjcial cut
• n hit amplitude...

Amplitude: (ADC counts)

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MC Study

• Make a cut at 25ADC

amplitude

• Drastic loss of

effjciency with drift distance for almost all wires

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Real 35-ton Data

• For real data, situation is grim
• For clarity, straight line fjt is

shown in red, rather than jagged TGraph lines

• Hit fjnding threshold: 2*RMS
• Interesting, some wires have

very low effjciency, consistently.

– TPC3, not yet corrected for

whether wires are “active” or not during the run

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Real 35-ton Data

“REAL” HITS

Threshold = 2.0*RMS

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Real 35-ton Data

*Note: Effective track length on wire is undefined if a hit is not on a track. Use wire pitch (0.449cm) instead.

“NOISE” HITS

Threshold = 2.0*RMS

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Real 35-ton Data

Threshold: 1.5*RMS REAL HITS NOISE HITS

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Real 35-ton Data

Threshold: 2.5*RMS REAL HITS NOISE HITS

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Moving Forward

• The RobustHitFinder seems to be

validated for low-noise data (i.e. MC)

• No conclusion yet on real 35-ton

data

• Need to make extremely tight

cuts on channel/wire noise RMS

• Lots of checking with event

display

• Possibly found more “Bad” wires

to add to the list, will probably update the list before the end of this week.

• Purity measurement is

still not out of reach!

• With enough events,

even 1 good wire should be able to give a decent measurement of purity!

• The more consistently

good wires, the better!