The PHENIX Detector

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

Looking 'Inside' a Collision

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.

A Massive Machine

PHENIX weighs 4,000 tons and has a dozen detector sub-systems. 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.

Funding Agencies