Raw data

The raw inputs are ROOT files from NPS replay or Geant4+SIMC simulation. These paths are available on the JLab filesystem and may not be visible outside the JLab network.

Locations

Source	Format	JLab path
HCANA replay	ROOT tree T	/cache/hallc/c-nps/analysis/pass2/replays/updated/nps_hms_coin_{run}_{seg}_1_-1.root
Geant4 + SIMC example	ROOT tree nerd	/lustre24/expphy/volatile/eic/ckin/nps_geant4/nps_excl_pi0_x36_6_short.root

In the replay filename, run and seg are the run and segment numbers. The 1 is retained for historical naming compatibility, and -1 denotes a file containing all requested events.

HCANA replay ROOT structure

The replay converter reads tree T by default. Its important branches are:

Branch	Structure and use
Ndata.NPS.cal.fly.adcSampWaveform	Number of valid entries in the flattened waveform buffer
NPS.cal.fly.adcSampWaveform	Repeated block records used as node features
Ndata.NPS.cal.fly.block_clusterID	Number of HCANA cluster-label entries
NPS.cal.fly.block_clusterID	Cluster ID indexed by block; -1 means unassigned
NPS.cal.vtpClusX/Y/E/Time/Size	Recorded VTP cluster position, energy, time, and size, used by VTP matching

Flattened waveform encoding

NPS.cal.fly.adcSampWaveform is decoded as:

block_id, num_samples, sample_0, ..., sample_(num_samples-1),
block_id, num_samples, sample_0, ...

The converter accepts unique block IDs from 0 through 1079 and expects each retained waveform to have 110 samples. Invalid and duplicate block records are skipped. A truncated record stops waveform parsing, while an event with no waveform or a non-110-sample first waveform is rejected.

Blocks labelled -1 in NPS.cal.fly.block_clusterID are omitted from the cluster map used to construct targets and edges.

Geant4 + SIMC ROOT structure

SIMC generates the Hall C physics events. The HallC SIMC-Geant framework transports those events through Geant4, simulates the NPS response, reconstructs clusters, and writes the ROOT ntuple consumed here.

The simulation converter reads tree nerd by default. Its expected branches fall into four groups:

Group	Representative branches	Meaning
Event and calorimeter	evtNb, edep[1080]	Event number and deposited energy for every NPS block
Photon truth	phot1_*, phot2_*	Hit flags, generation vertices, calorimeter impact points, cluster sizes/positions, and deposited energies
Reconstructed clusters	nClusters, clust_E/X/Y/Size, clust_Signals	Cluster summaries and block-level pulse data
SIMC kinematics	Q2, W, t, Weight, spectrometer variables, photon four-vectors, and vertex variables	Original generator-level event information

The clust_Signals branch is a flat vector encoding a nested cluster structure:

cluster_id, number_of_blocks,
  block_id, number_of_pulses,
    pulse_time, pulse_energy,
    pulse_time, pulse_energy, ...
  block_id, number_of_pulses, ...
cluster_id, number_of_blocks, ...

Although the raw branch stores each pulse as (time, energy), the simulation converter arranges each output feature pair as (energy, time).

Next: Training data describes the graphs derived from these ROOT sources.