The PHENIX experiment in the RHIC run 7

PHENIX is one of two large experiments at Brookhaven National Laboratory´s Relativistic Heavy Ion Collider (RHIC). Previously, the PHENIX experiment had completed very successful Runs that featured different beam species in RHIC. Since the previous Au+Au run in 2004, we had improved the performance of the data acquisition system by introducing several key technologies, such as distributed compression and multi-event buffering, that had increased the event rate to 5 KHz for the smaller collision systems that we measured since, Cu+Cu, and p+p. However, this rate had yet to be reached in the largest and most demanding collision system, Au+Au at 200 AGeV. Previously, the data logging capability had been demonstrated to exceed 600 MB/S, although this value had never reached in actual running. The RHIC luminosity and the smaller collision systems before did not deliver enough data to saturate the logging capability. In this Run 7, we exceeded the 600 MB/S logging rate for the highest multiplicities, where we also reached the current practical limit of 5 KHz event rate with the large events size. We have in the past used GRID middleware tools to transfer substantial data volumes in the order of 400 TB off-site in order to make use of remote computing capacity in Japan, France, and other sites in the US, and used this technology to achieve priority processing of triggered events again in Run 7. The Run 7 also introduced several new prototype detectors in the experiment, a new high-resolution time-of-flight detector, a reaction plane detector, a Muon Piston Calorimeter, and, as a prototype, a Hadron Blind Detector that is designed to tag the background from conversion electrons and improve the photon and electron measurement capability of the PHENIX apparatus We will describe the ingredients which made those highest rates possible, and show some performance figures.