1. 3D Event reconstruction in ArgoNeuT Maddalena Antonello and Ornella Palamara 11 gennaio 20161M.Antonello - INFN, LNGS

2. 3D reconstruction procedure 1.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). 11 gennaio 20162M.Antonello - INFN, LNGS

3. Hit Finding: simulated muon The algorithm has not been optimized to match ArgoNeuT signal features. 11 gennaio 20163M.Antonello - INFN, LNGS

4. Hit Identification A 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 11 gennaio 20164M.Antonello - INFN, LNGS

5. 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 11 gennaio 20165M.Antonello - INFN, LNGS

6. 2D Track reconstruction : simulated muon 11 gennaio 20166M.Antonello - INFN, LNGS

7. 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. 11 gennaio 20167M.Antonello - INFN, LNGS

8. 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 w 0 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 1 Matching hits w0w0 w o : Number of Induction wires intersecting with one wire from the Collection view 11 gennaio 20168M.Antonello - INFN, LNGS

9. 3D Track reconstruction: step 1 Matching hits aHitbHit bHitMatch aHitMatch 11 gennaio 20169M.Antonello - INFN, LNGS

10. 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. 3D Track reconstruction: step 1 Matching hits 11 gennaio 201610M.Antonello - INFN, LNGS

11. Once 2 Hits are matched one 3D Hit is created. The 3D Hit spatial coordinates are defined as follows: p = 4mm (wire picth) ϑ w = 60 degrees (angle of Ind/Coll wires with respect to horizontal) w coll = Collection wire coordinate w ind = Induction wire coordinate s = drift sample coordinate v = electron drift velocity f = readout sampling frequency. d = max drift length w 0 = number of Induction wires intersecting with one collection wire 3D Track reconstruction: step 2 3D Hit creation 11 gennaio 201611M.Antonello - INFN, LNGS

12. Reference frame definition Cathode X Y Z Collection wires Induction wires ArgoNeuT Sensitive volume (40x46x100 cm 3 ) beam 11 gennaio 201612M.Antonello - INFN, LNGS

13. 3D Track: simulated muon 11 gennaio 201613M.Antonello - INFN, LNGS

14. 3D reconstruction: evaluation on ArgoNeuT real crossing muons Sample The reconstructed 3D tracks are represented inside ArgoNeuT sensitive volume. 11 gennaio 201614M.Antonello - INFN, LNGS

15. Y (mm) 3D reconstruction: evaluation on ArgoNeuT real crossing muons TOP 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 11 gennaio 201615M.Antonello - INFN, LNGS

16. “Neutrino-like” event: Run 422 Event 13 Collection View Induction View 11 gennaio 201616M.Antonello - INFN, LNGS

17. “Neutrino-like” 3D reconstruction Very few hits on Induction, Hit finding must be optimized 11 gennaio 201617M.Antonello - INFN, LNGS

18. 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). 11 gennaio 201618M.Antonello - INFN, LNGS

19. Hit extraction Amplitude (ADC) Drift Sample: [0,2048] Hit reconstruction: main parameters View: Collection or Induction Wire number: [0,239] 11 gennaio 201619M.Antonello - INFN, LNGS