Hardware controls for the STAR experiment at RHIC Reichhold, D; Bieser, F; Bordua, M ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2003, Letnik:
499, Številka:
2
Journal Article
Recenzirano
The STAR detector sits in a high radiation area when operating normally; therefore it was necessary to develop a robust system to remotely control all hardware. The STAR hardware controls system ...monitors and controls approximately 14,000 parameters in the STAR detector. Voltages, currents, temperatures, and other parameters are monitored. Effort has been minimized by the adoption of experiment-wide standards and the use of pre-packaged software tools. The system is based on the Experimental Physics and Industrial Control System (EPICS)
1. VME processors communicate with subsystem-based sensors over a variety of field busses, with High-level Data Link Control (HDLC) being the most prevalent. Other features of the system include interfaces to accelerator and magnet control systems, a web-based archiver, and C++-based communication between STAR online, run control and hardware controls and their associated databases. The system has been designed for easy expansion as new detector elements are installed in STAR.
A hardware controls system has been implemented for the STAR experiment at RHIC. Approximately 10000 parameters governing experiment operation are currently controlled and monitored. The system is ...based on the Experimental Physics and Industrial Control System (EPICS). The architecture of STAR hardware controls is presented as well as the results of operation of the integrated baseline system. Novel features of the system include a specialized field bus (High-level Data Link Control-HDLC), new EPICS record support, Control DEVice (CDEV) interfaces to accelerator and magnet control systems, and C++ based communication between STAR online and Hardware Controls and their associated databases.
The forward time projection chamber in STAR Ackermann, K.H.; Bieser, F.; Brady, F.P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2003, Letnik:
499, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Two cylindrical forward TPC detectors are described which were constructed to extend the phase space coverage of the STAR experiment to the region 2.5<|
η|<4.0. For optimal use of the available space ...and in order to cope with the high track density of central Au+Au collisions at RHIC, a novel design was developed using radial drift in a low diffusion gas. From prototype measurements a 2-track resolution of 1–
2
mm
is expected.
We report the first measurement of the opening angle distribution between pairs of jets produced in high-energy collisions of transversely polarized protons. The measurement probes (Sivers) ...correlations between the transverse spin orientation of a proton and the transverse momentum directions of its partons. With both beams polarized, the wide pseudorapidity (-1< or = eta < or = +2) coverage for jets permits separation of Sivers functions for the valence and sea regions. The resulting asymmetries are all consistent with zero and considerably smaller than Sivers effects observed in semi-inclusive deep inelastic scattering. We discuss theoretical attempts to reconcile the new results with the sizable transverse spin effects seen in semi-inclusive deep inelastic scattering and forward hadron production in pp collisions.
The balance function is a new observable based on the principle that charge is locally conserved when particles are pair produced. Balance functions have been measured for charged particle pairs and ...identified charged pion pairs in Au+Au collisions at the square root of SNN = 130 GeV at the Relativistic Heavy Ion Collider using STAR. Balance functions for peripheral collisions have widths consistent with model predictions based on a superposition of nucleon-nucleon scattering. Widths in central collisions are smaller, consistent with trends predicted by models incorporating late hadronization.
Azimuthal correlations for large transverse momentum charged hadrons have been measured over a wide pseudorapidity range and full azimuth in Au+Au and p+p collisions at sqrts(NN)=200 GeV. The ...small-angle correlations observed in p+p collisions and at all centralities of Au+Au collisions are characteristic of hard-scattering processes previously observed in high-energy collisions. A strong back-to-back correlation exists for p+p and peripheral Au+Au. In contrast, the back-to-back correlations are reduced considerably in the most central Au+Au collisions, indicating substantial interaction as the hard-scattered partons or their fragmentation products traverse the medium.
Inclusive transverse momentum distributions of charged hadrons within 0.2<p(T)<6.0 GeV/c have been measured over a broad range of centrality for Au+Au collisions at sqrts(NN)=130 GeV. Hadron yields ...are suppressed at high p(T) in central collisions relative to peripheral collisions and to a nucleon-nucleon reference scaled for collision geometry. Peripheral collisions are not suppressed relative to the nucleon-nucleon reference. The suppression varies continuously at intermediate centralities. The results indicate significant nuclear medium effects on high-p(T) hadron production in heavy-ion collisions at high energy.
We report STAR results on the azimuthal anisotropy parameter v(2) for strange particles K(0)(S), Lambda, and Lambda at midrapidity in Au+Au collisions at sqrts(NN)=130 GeV at the Relativistic Heavy ...Ion Collider. The value of v(2) as a function of transverse momentum, p(t), of the produced particle and collision centrality is presented for both particles up to p(t) approximately 3.0 GeV/c. A strong p(t) dependence in v(2) is observed up to 2.0 GeV/c. The v(2) measurement is compared with hydrodynamic model calculations. The physics implications of the p(t) integrated v(2) magnitude as a function of particle mass are also discussed.
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