Gold hits gold at Brookhaven

12 July 2000

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Just a month ago, on 10 June, the Relativistic Heavy Ion Collider (RHIC) at the Brookhaven National Laboratory (BNL) in New York began to make beams of high-energy gold nuclei collide head on, in an attempt to create quark-gluon plasma, a state of matter that should have existed only ten millionths of a second after the Big Bang. The image shows the aftermath of a head-on collision between nuclei, each with an energy of 30 GeV per nucleon, at the heart of the STAR detector. Around 1000 tracks of charged particles spray outwards leaving tracks in the Time Projection Chamber (TPC) - a segmented cylindrical structure which surrounds the pipes that carry the counter-rotating beams. This image shows the view looking at the end of the cylinder (outlined by the fine white line); a view from the side can be seen here. The TPC is basically a volume that is filled with gas and subject to an electric field. The charged particles leave trails of ionised gas, which are sensed at the end of the chamber. The TPC in STAR is the world's largest, with a volume of about 50 cubic metres.

Credit: STAR collaboration / Brookhaven National Laboratory