PHENIX detectorThe PHENIX detector records many different particles emerging from RHIC collisions, including photons, electrons, muons, and quark-containing particles called hadrons.

Photons (particles of light) and leptons (electrons and muons) are not affected by the strong force, which binds quarks and gluons together into hadrons. Because they can emerge unchanged from the interior of a RHIC collision, photons and leptons carry unmodified information about processes within the collision. A good analogy is that PHENIX looks "inside" the hot, dense matter formed in the collision, much like x-ray or MRI images show medical doctors the "inside" of the human body. For example, escaping photons can reveal information about the temperature of the collision.

PHENIX schematic

PHENIX weighs 4,000 tons and has a dozen detector subsystems. Three large steel magnets produce high magnetic fields to bend charged particles along curved paths. Tracking chambers record hits along the flight path to measure the curvature and thus determine each particle's momentum. Other detectors identify the particle type and/or measure the particle's energy. Still others record where the collision occurred and determine whether each collision was "head-on" (central), a "near-miss" (peripheral), or something in between.

PHENIX has over 450 members from 51 institutions in 11 countries. The PHENIX detector is located at the 8 o'clock position on the RHIC ring.

PHENIX experimental group home page

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working inside PHENIX
Working inside the massive PHENIX detector.


A computer image generated from data collected at the PHENIX detector during RHIC's second run cycle.Reconstructed tracks (in green) point towards the location of the collisions. The beam path is shown in red.