Output filename convention
LARDON writes reconstruction output to an HDF5 file. The filename is constructed as:
{detector}_{run}_{sub}[_{flow}{writer}[_s{server}]][_{outname}].h5
{flow}{writer} suffix is only added when either -flow or -writer is set to a non-default value.{outname} suffix is only added when -out is provided.- Without
-job, the file is written to $LARDON_RECO/. With -job, it is written to the current working directory.
When -flow and -writer are both omitted (left at their default of -1), LARDON treats both as 0 internally and produces no flow/writer suffix in the output filename. If you explicitly pass -flow 0 -writer 0, LARDON does add the _00 suffix because the values differ from the internal default.
Examples
Single Event
All Events
PDS + TPC
Special Modes
Example 1 — PDVD TPC reconstruction, single eventProcess only event 11 from a PDVD file. The file np02vd_raw_run039229_0024_df-s05-d4_dw_0_20250829T115242.hdf5 requires -flow 4 -writer 0 -serv 5 to identify the correct dataflow/writer/server combination, and -hash 86/ad because the file lives in a hashed subdirectory.lardon -det pdvd -run 39229 -sub 24 \
-flow 4 -writer 0 -serv 5 \
-hash 86/ad \
-event 11 \
-out one_event \
-trk
$LARDON_RECO/pdvd_39229_24_40_s5_one_event.h5The _40 component comes from -flow 4 and -writer 0 concatenated. The _s5 component is appended because -serv 5 is non-default. If -serv were omitted or left at -1, the output would be pdvd_39229_24_40_one_event.h5.-event 11 is equivalent to -skip 11 -n 12. Only event 11 is reconstructed; events 0–10 are skipped.
Example 2 — PDVD TPC reconstruction, all eventsProcess every event in a PDVD file. -flow 0 -writer 0 are provided explicitly here, but because both are 0 they could be omitted entirely with identical results.lardon -det pdvd -run 39246 -sub 6 \
-flow 0 -writer 0 \
-out full_example \
-trk
$LARDON_RECO/pdvd_39246_00_full_example.h5The _00 suffix comes from -flow 0 -writer 0 being explicitly set to non-default values. Had both flags been omitted, the output would be pdvd_39246_6_full_example.h5.
Example 3 — VD Coldbox TPC reconstruction, first 10 eventsProcess the first 10 events of a VD Coldbox bottom file. The -hash flag points to the hashed subdirectory; -flow and -writer are omitted because they are both 0.lardon -det cbbot -run 37040 -sub 23 \
-hash 5a/a2 \
-n 10 \
-out few_events \
-trk
$LARDON_RECO/cbbot_37040_23_few_events.h5 Example 4 — TPC and PDS reconstruction via XRootD path, events 5 and 6Run both TPC and PDS reconstruction on events 5 and 6 of a VD Coldbox file accessed directly via an XRootD URL. The -file flag extracts run, subfile, and detector information from the filename automatically.lardon -file root://somewhere.abc:1094/directory/raw/data/np02vdcoldbox_raw_run037041_0079_df-s02-d0_dw_0_20250705T130324.hdf5 \
-n 6 -skip 4 \
-trk -pds \
-out evt_5_6_both_reco
$LARDON_RECO/cbbot_37041_79_evt_5_6_both_reco.h5The -skip 4 and -n 6 combination processes events at indices 4 and 5 (i.e. the 5th and 6th events, zero-indexed).Ensure your XRootD authentication (justin / rucio) is set up before using -file with root:// paths. In set_lardon.sh, uncomment the two lines related to xroot.
Online monitoringAdd -online to any standard invocation to enable LARDONline mode. LARDON produces an event display and control plots live during processing.lardon -det pdvd -run 39229 -sub 24 \
-flow 4 -writer 0 -serv 5 \
-hash 86/ad \
-trk -online
Gallery mode (PDVD only)Gallery mode renders data with an effective channel mapping so that tracks appear unbroken across CRP boundaries. Choose one of beam, top, bottom, or both.lardon -det pdvd -run 39229 -sub 24 \
-flow 4 -writer 0 -serv 5 \
-hash 86/ad \
-gallery beam \
-trk
Gallery mode is only supported for pdvd. Using any other detector will cause LARDON to exit.
Calibration (pulsing) modeAdd -pulse to process charge pulsing (calibration) data. LARDON finds and fits pulses in the raw waveforms.lardon -det cbbot -run 37040 -sub 23 \
-hash 5a/a2 \
-pulse \
-out calib_run
Pulsing reconstruction is significantly slower than standard track reconstruction. Expect substantially longer run times.
Batch job modeAdd -job when submitting LARDON as a batch job (e.g. via HTCondor). The output HDF5 file is written to the current working directory instead of $LARDON_RECO.lardon -det pdvd -run 39246 -sub 6 \
-trk \
-out batch_output \
-job
./pdvd_39246_6_batch_output.h5 (in the job’s working directory) 
