The PHENIX detector is designed to perform a broad study of A-A, p-A, and p-p collisions to investigate nuclear matter under extreme conditions. A wide variety of probes, sensitive to all timescales, are used to study systematic variations with species and energy as well as to measure the spin structure of the nucleon. Designing for the needs of the heavy-ion and polarized-proton programs has produced a detector with unparalleled capabilities. PHENIX measures electron and muon pairs, photons, and hadrons with excellent energy and momentum resolution. The detector consists of a large number of subsystems that are discussed in other papers in this volume. The overall design parameters of the detector are presented. The PHENIX detector is designed to perform a broad study of A-A, p-A, and p-p collisions to investigate nuclear matter under extreme conditions. A wide variety of probes, sensitive to all timescales, are used to study systematic variations with species and energy as well as to measure the spin structure of the nucleon. Designing for the needs of the heavy-ion and polarized-proton programs has produced a detector with unparalleled capabilities. PHENIX measures electron and muon pairs, photons, and hadrons with excellent energy and momentum resolution. The detector consists of a large number of subsystems that are discussed in other papers in this volume. The overall design parameters of the detector are presented. Disciplines Engineering Physics | Physics Comments This is a manuscript of an article from Nuclear Instruments and Methods in Physics Research

[1] By exploiting data from the STEREO/heliospheric imagers (HI) we extend a well-established technique developed for coronal analysis by producing timeelongation plots that reveal the nature of solar transient activity over a far more extensive region of the heliosphere than previously possible from coronagraph images. Despite the simplicity of these plots, their power in demonstrating how the plethora of ascending coronal features observed near the Sun evolve as they move antisunward is obvious. The time-elongation profile of a transient tracked by HI can, moreover, be used to establish its angle out of the plane-ofthe-sky; an illustration of such analysis reveals coronal mass ejection material that can be clearly observed propagating out to distances beyond 1AU. This work confirms the value of the time-elongation format in identifying/characterising transient activity in the inner heliosphere, whilst also validating the ability of HI to continuously monitor solar ejecta out to and beyond 1AU. Citation: Davies, J. A., R. A.

The centrality dependence of transverse momentum distributions and yields for ± , K ± , p, and p in Au + Au collisions at ͱ s NN = 200 GeV at midrapidity are measured by the PHENIX experiment at the Relativistic Heavy Ion Collider. We observe a clear particle mass dependence of the shapes of transverse momentum spectra in central collisions below ϳ2 GeV/ c in p T. Both mean transverse momenta and particle yields per participant pair increase from peripheral to midcentral and saturate at the most central collisions for all particle species. We also measure particle ratios of − / + , K − / K + , p / p, K / , p / , and p / as a function of p T and collision centrality. The ratios of equal mass particle yields are independent of p T and centrality within the experimental uncertainties. In central collisions at intermediate transverse momenta ϳ1.5-4.5 GeV/ c, proton and antiproton yields constitute a significant fraction of the charged hadron production and show a scaling behavior different from that of pions.