Construction of a detector for use in relativistic heavy ion experiments will be carried out. The detector will be sited at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. The detector, known as PHOBOS, will provide a first look at the behavior and decay of matter at the extreme energy densities that will be created in gold-on-gold collisions with energies of 100GeV/nucleon in the center-of-mass system. This work is aimed at characterizing the hypothesized quark-gluon plasma which is created in such energetic collisions, and in which quarks and gluons are thought to be deconfined, unlike the case in normal hadronic matter. Specific elements of the PHOBOS detector associated with the present activity include the particle identification system which will permit the different mesons coming from decay of the quark-gluon plasma to be separately identified, which is important to characterizing the properties of the plasma. The data gathered by PHOBOS will extend our knowledge of matter to energies and densities thought to have existed only in the first microseconds of the early universe. This topic is a high priority within US nuclear science, as established by the joint NSF/DOE Nuclear Science Advisory Committee in its 1996 Long Range Plan. Education of students and postdocs is a strong component of this experimental program.
