3D Event reconstruction in ArgoNeuT Maddalena Antonello and Ornella Palamara 11 gennaio...

3D Event reconstructionin ArgoNeuT

Maddalena Antonelloand

Ornella Palamara

21 aprile 2023 1M.Antonello - INFN, LNGS

3D reconstruction procedure1. Hit identification: the hits are independently searched for in every

wire as output signal regions of a certain width above the baseline output value.

2. Fine hit reconstruction: the parameters defining the hit (position, height, area), which contain the physical information, are precisely determined.

3. Cluster reconstruction: hits are grouped into common charge deposition distributions based on their position in the wire/drift coordinate plane.

4. 2D Tracks reconstruction: clusters are, when possible, expanded and merged together to form 2D Tracks.

5. Three-dimensional (3D) hit reconstruction: the hit spatial coordinates are reconstructed using the association of hits from 2D Tracks belonging to different views (Collection and Induction).

The full procedure has been firstly tested on a straight muon Track with dip angle of 2 degrees ( track simulated by Bruce).21 aprile 2023 2M.Antonello - INFN, LNGS

Hit Finding: simulated muon

The algorithm has not been optimized to match ArgoNeuT signal features.


Hit IdentificationA hit is identified when the signal stays above a predefined threshold for a certain number of

samples. The threshold is relative to the local baseline

Local Baseline Threshold


Clusters and 2D Tracks reconstruction

• The goal of the cluster reconstruction is to perform a first grouping of hits belonging to common charge deposition distributions, such as tracks or showers.

• A cluster is defined as a group of hits within the wire/drift coordinate plane that are linked together.

• A link is defined as a pair of hits coming from consecutive wires and having overlapping drift coordinate ranges.

• Clusters are finally merged into 2D Tracks


2D Track reconstruction : simulated muon


3D Track reconstruction: motivations • The goals of the 3D track reconstruction is the determination of:

• the space coordinates (x,y,z) of each point

• the spatial orientation (ϑ,φ) of the different energy deposition segments produced by the ionizing tracks crossing the LAr sensitive volume• the track pitch length Δx (i.e. the effective length of the track “seen” by the wire).

• These information are necessary to apply corrections to the signal amplitudes due to the geometry of the track and to the e-lifetime when measuring the energy released.


• The 3D track reconstruction is performed through the creation of a sequence of 3DHits.

• Each wire plane constrains two spatial degrees of freedom of the hits, one common to all the wire planes (drift coordinate), and one specific for each plane (wire coordinate).

• 2 Hits from different views (Collection and Induction) are matched together if their wire coordinates are compatible (within w0 wires) and if their drift coordinates are compatible (within a few sample, also taking into account the drift shift due to the 4mm spacing between Induction and Collection planes).

3D Track reconstruction: step 1Matching hits

w0

wo : Number of Induction wires intersecting with one wire from the Collection view



aHitbHit

bHitMatch

aHitMatch


• 2D Track Bound Hits of Collection view are matched with 2D Track Bound Hits of Induction view.

• The algorithm try to match every remaining Hit of the 2D Collection Track as follows:– looks for hits, belonging to the same Cluster, that are

already matched;– Get the relative matching Hit in the Induction view;– Use the matching Hit already found as hint looking for

new matching inside the same Cluster.



• Once 2 Hits are matched one 3D Hit is created. The 3D Hit spatial coordinates are defined as follows:

€

x =p

2cosθw(wcoll −wind + w0)

y = d −sv

f

z =p

2sinθw(wcoll + wind −w0)

p = 4mm (wire picth)ϑw= 60 degrees (angle of Ind/Coll wires with respect to horizontal)wcoll = Collection wire coordinatewind = Induction wire coordinates = drift sample coordinatev = electron drift velocityf = readout sampling frequency. d = max drift lengthw0 = number of Induction wires intersecting with one collection wire

3D Track reconstruction: step 23D Hit creation


Reference frame definition

Cathode

X

Y

Z

Collection wires Induction wires

ArgoNeuT Sensitive volume (40x46x100 cm3)

beam


3D Track: simulated muon


3D reconstruction: evaluation on ArgoNeuT real crossing muons

Sam

ple

Sam

ple

The reconstructed 3D tracksare represented inside ArgoNeuT sensitive volume.


Y (m

m)

3D reconstruction: evaluation on ArgoNeuT real crossing muonsTOP VIEW

S1

S2

S3

- The 3D Tracks reflect the External Trigger geometry Trigger logic : (S1&S2)&S3 - Due to the low Electric Field applied, half chamber was barely read


“Neutrino-like” event: Run 422 Event 13

Collection ViewCollection View

Induction ViewInduction View


“Neutrino-like” 3D reconstruction

Very few hits on Induction,Hit finding must be optimized


Conclusions• Point by point 3D Track reconstruction has been performed for 1

simulated muon, 5 real crossing muons and one event with multiplicity >1.

• The procedure seems to work quite well, but improvements can be done– Hit Finding Algorithm optimized for ArgoNeuT electronics (--> B.Rebel)– 2D Hits matching algorithm can be improved (through parameter

optimization)• Precise measurement of the Electron drift velocity is necessary in order

to correctly reconstruct the Y cordinate.• Next steps - dE/dx measurement (using calibration factor for ADC-> Charge

conversion and the track pitch length Δx calculated on the base of the 3D reconstruction) - LAr purity measurement done with many tracks after corrections for the Electron Lifetime and the track pitch length (tracks can be now grouped with respect to their distance from wire planes).- Technical issue: integration of the 3D reconstruction code into LArSoft (after

further tests and optimization).21 aprile 2023 18M.Antonello - INFN, LNGS

Hit extraction

Ampl

itude

(AD

C)

Drift Sample:[0,2048]

Hit reconstruction: main parameters

View: Collection or InductionWire number: [0,239]


3D Event reconstruction in ArgoNeuT Maddalena Antonello and Ornella Palamara 11 gennaio...

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