Particle Detector Simulator

Collision Event

Demo particle

Events fired

Tracks live

Primary ID

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Primary energy

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How particle ID works

A collider detector is built as concentric barrel layers around the beam axis, each sensitive to a different physics process:

Tracker — silicon strips/pixels in a solenoid magnetic field. Only charged particles bend; the curvature radius gives momentum (tighter curve = lower momentum).
ECAL — dense crystal/liquid-argon absorber. Electrons and photons dump their entire energy here in an electromagnetic shower and stop.
HCAL — thick steel/scintillator stack. Hadrons (protons, pions) punch through the ECAL and shower here instead.
Muon chambers — the outermost layer. Only muons are massive and weakly-interacting enough to survive both calorimeters and reach here.

e⁻ / γ : ECAL stop,   no HCAL,  no muon hit
   pi  : ECAL tick,   HCAL stop, no muon hit
   mu  : ECAL tick,   HCAL tick, MUON hit

The combination of which layers fired — plus whether the track curved in the tracker (charged vs. neutral) — is exactly how real detectors like ATLAS and CMS at the LHC identify a particle's type and reconstruct its energy, without ever seeing the particle directly.

Tracker ECAL HCAL Muon chambers

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