data_info.txt

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Event hits

The hits file contains the following values for each hit/entry:

hit_id: numerical identifier of the hit inside the event.
x, y, z: measured x, y, z position (in millimeter) of the hit in global coordinates.
volume_id: numerical identifier of the detector group.
layer_id: numerical identifier of the detector layer inside the group.
module_id: numerical identifier of the detector module inside the layer.

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Event hit cells

The cells file contains the constituent active detector cells that comprise each hit. The cells can be used to refine the hit to track association. A cell is the smallest granularity inside each detector module, much like a pixel on a screen, except that depending on the volume_id a cell can be a square or a long rectangle. It is identified by two channel identifiers that are unique within each detector module and encode the position, much like column/row numbers of a matrix. A cell can provide signal information that the detector module has recorded in addition to the position. Depending on the detector type only one of the channel identifiers is valid, e.g. for the strip detectors, and the value might have different resolution.

hit_id: numerical identifier of the hit as defined in the hits file.
ch0, ch1: channel identifier/coordinates unique within one module.
value: signal value information, e.g. how much charge a particle has deposited.

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Event particles

The particles files contains the following values for each particle/entry:

particle_id: numerical identifier of the particle inside the event.
vx, vy, vz: initial position or vertex (in millimeters) in global coordinates.
px, py, pz: initial momentum (in GeV/c) along each global axis.
q: particle charge (as multiple of the absolute electron charge).
nhits: number of hits generated by this particle.
All entries contain the generated information or ground truth.

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Event truth

The truth file contains the mapping between hits and generating particles and the true particle state at each measured hit. Each entry maps one hit to one particle.

hit_id: numerical identifier of the hit as defined in the hits file.
particle_id: numerical identifier of the generating particle as defined in the particles file. A value of 0 means that the hit did not originate from a reconstructible particle, but e.g. from detector noise.
tx, ty, tz true intersection point in global coordinates (in millimeters) between the particle trajectory and the sensitive surface.
tpx, tpy, tpz true particle momentum (in GeV/c) in the global coordinate system at the intersection point. The corresponding vector is tangent to the particle trajectory at the intersection point.
weight per-hit weight used for the scoring metric; total sum of weights within one event equals to one.