Task #13473

Milestone #13399: Parent reconstruction milestones/tasks for reconstruction necessary for MCC8 and reconstruction "v6"

Milestone #13400: MCC8 and "v6" reconstruction development

Milestone #13405: Shower Reconstruction

Task #13420: Shower Reconstruction - Pandora tasks

Particle (esp. shower) merging

Added by John Marshall over 4 years ago. Updated over 4 years ago.

Target version:
Start date:
Due date:
% Done:


Estimated time:
Duration: 55


This is a rather broad issue encompassing:
i). Merging existing Particles together to increase (most likely) shower completeness.
ii). Merging remnants with existing Particles to increase completeness.
iii). Bringing remnants into existence as their own Particles.

Speculative, longer-term: experiment with moving the shower branch growing into a 3x2D operation, with branch additions considered from all view at same time (currently additions are made completely independently).


#1 Updated by Lorena Escudero sanchez over 4 years ago

  • % Done changed from 0 to 30

#2 Updated by John Marshall over 4 years ago

  • % Done changed from 30 to 80

Key issues affecting completeness of reconstructed showers:
1. Elements of sparse shower excluded - Appear as separate 3D Particles, or Remnant 2D Clusters (not in Particles)
2. Event Slicing (to tackle left-over cosmic rays) splits shower into multiple slices.

Use sliding linear fits to 3D Shower Clusters to define 3D cones:
-Use cones to aid collection of downstream fragments.
-Can use neutrino interaction vertex to define/choose cone direction.
-Need to be rather “generous” to collection most/all fragments.

-3D linear fit provides an axis; divide into layers. Assign Hits to layers and calculate layer “fit contributions”.
-By sliding/summing along nearby n layers, can obtain a local linear fit position and direction.
-Now exploit sliding 3D fit results to define cones:
--Fit position in chosen layer can provide cone apex
--Mean fit direction for next m layers defines direction
--Hit positions/algorithm chooses angle and length.

Exploit reusable 3DSlidingConeFit functionality in a number of algorithms and tools in reconstruction:
1. 3D Event Slicing: use cones to collect 3D Hits for more complete slices.
2. 3D Particle → 3D Particles: shower cone fits pick up downstream 3D fragment Particles.
3. 3D Particle → 2D Clusters: project cone fits, pick up downstream 2D remnant Clusters.

Also add simple backstop alg to assign any left-over “isolated” Clusters to nearest Particle within range.

Associated pattern recognition performance shown at MicroBooNE collaboration meeting.

Also available in: Atom PDF