Reconstructing Neutrino Interactions in

rucksackbulgeAI and Robotics

Dec 1, 2013 (3 years and 6 months ago)

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Reconstructing Neutrino Interactions in

Liquid Argon TPCs


Ben Newell

Steve Dennis

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Outline


LAr
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TPCs


Automation desirable


Algorithmic recognition

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Cellular Automata


Conway's 'Game of Life'


Local rules


Cell states update simultaneously

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CATS


The Cellular Automaton at HERA
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B


HERA
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B experiment uses eight 'superlayers'


Create 'track segments' between layers


Cellular automaton on track segments

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Cellular Automata for Track Reconstruction


Cells have an index


initially 1


Local


only neighbours


Common endpoint


'Breaking angle'


Principal Direction

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The CA Algorithm


Forward Pass


For each cell:


Look for leftward neighbours


Check if any have same index


Mark index to update



Update all indices


Repeat

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The CA Algorithm


Reverse Pass


Start at highest index cell


Run to cell of index 1 using steps of 1


Mark cells used


Repeat with unused cells


Build all possible paths


Result: List of track candidates

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CARLA


A Cellular Automaton for Reconstruction in
Liquid Argon


Implemented in Python


Extra steps required to suit our needs

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Clustering the Data


LAr
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TPC resolution ~mm


Thousands of voxels in principal direction


Performance problems


Clustering


Voxel size


Clustering orthogonal to principal direction


Reject 'lone' points

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Post
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Processing


Problems:


Breaking


Kinks


Clones



Filtering by shared points


Track cleaning


Breaker


Merger

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Generalisation to 3D


Simple to work in higher dimensions


Directionality


May miss tracks



Solution: permute the axes and run on each


Recombine the results

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CARLA in 3D

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Parameters for reconstruction


Voxel size


Clustering radius


Cell tolerance


Filtering tolerance


Breaking Angle


Merger


Direction Tolerance


Distance Tolerance


Breaker


Correlation Tolerance


Segment length

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Early results

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Efficiency of CARLA

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2D: Efficiency of reconstructing correct 2 tracks

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2D: Variation of efficiency with breaking angle

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2D: Variation of efficiency with voxel size

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3D: Opening Angle Variance

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3D: Opening Angle Variance

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CARLA in 3D

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Future Developments


Improvements to filtering


Documentation


User Interface