atlantis

name	atlantis
description	Use when visualizing ATLAS detector events with the Atlantis event display: launching the Atlantis GUI, opening JiveXML event files, producing JiveXML output from Athena reconstruction, or troubleshooting Java runtime issues in containerized environments.

Atlantis

Overview

Atlantis is the ATLAS event display — a Java-based graphical tool for visualizing detector events in 2D projections. It reads JiveXML files produced by the Athena JiveXML algorithm and provides interactive exploration of tracks, calorimeter deposits, muon hits, and jets across multiple detector views.

When to Use

• Visualizing reconstructed ATLAS events interactively
• Inspecting individual tracks, calorimeter clusters, or muon segments in 2D projections
• Producing event display images for talks, papers, or analysis documentation
• Debugging reconstruction output by examining event geometry

Key Concepts

Concept	Notes
JiveXML	XML format for event display data, produced by Athena
Y-X projection	Transverse view (beam axis perpendicular to screen)
R-Z projection	Longitudinal view (beam axis horizontal)
phi-eta view	Unrolled detector view in pseudorapidity vs azimuthal angle
Interactive cuts	Apply pT, eta, or object-type filters directly in the GUI

Canonical Patterns

Setup and launch

setupATLAS
lsetup atlantis

atlantis                         # launch GUI
atlantis file.xml               # open specific JiveXML event file
atlantis --file file.xml        # alternative syntax

Producing JiveXML files from Athena

Add the JiveXML algorithm to an Athena job to write event display data:

from AthenaCommon.AlgSequence import AlgSequence
topSequence = AlgSequence()
from JiveXML.JiveXMLConf import JiveXML__AlgoJiveXML
topSequence += JiveXML__AlgoJiveXML()

This writes one .xml file per event in the run directory. Control output with algorithm properties:

jivexml = JiveXML__AlgoJiveXML()
jivexml.AtlasRelease = "24.0.0"
jivexml.WriteToFile = True
jivexml.OnlineMode = False
topSequence += jivexml

Working with the GUI

• Navigate events: Use the event browser toolbar to step through events in a JiveXML file or directory
• Select objects: Click on tracks or clusters to inspect properties (pT, eta, phi, charge)
• Apply cuts: Use the cut panel to filter objects by pT threshold, eta range, or object type
• Export images: File → Save Canvas to export the current view as PNG or EPS

Gotchas

• Java runtime required: Atlantis is Java-based. Ensure a JRE is available in the environment (java -version to check).
• Singularity/Apptainer issues: Known Java display problems when running inside containers — set DISPLAY correctly or use VNC/X11 forwarding.
• Large XML files: Complex events with many tracks and clusters produce large JiveXML files. Limit output to events of interest in Athena.
• All ATLAS energy/momentum values are in MeV: Values displayed in the GUI follow ATLAS conventions.
• Custom objects: JiveXML output may need specific Athena configuration to include non-standard reconstruction objects.

Interop

• setupATLAS: lsetup atlantis requires a working ALRB environment — see the setupatlas skill.
• Athena: JiveXML files are produced by Athena reconstruction jobs; the JiveXML algorithm must be added to the job sequence.

Contact: [e-mail]

Docs

https://twiki.cern.ch/twiki/bin/viewauth/AtlasComputing/Atlantis

Additional info: http://atlantis.web.cern.ch