148 research outputs found
Test of the ALICE DDL: Test setups and Test of ALICE DDL Integration to ALICE TPC test system
Presentation made at the 4th Workshop on Electronics for LHC Experiments, INFN Rome, 21-25 September 1998.The Detector Data Link (DDL) has been developed to constitute a standard interface between the ALICE sub-detectors and the DAQ system.In this paper we present the test environment and the application software library made for supporting the DDL development and its integration into the ALICE detector system. The test setups contain VME64 crates, MVME processor cards, a VMETRO analyser, a logic-analyser and Read-out-Receiver (RORC) andDestination-Interface-Unit (DIU) cards. They made possible to measure the maximum throughput of the full read-out chain and also to measurethe transmission latencies. They support the functional and long-term stability tests as well
The ALICE detector data link
The ALICE detector data link has been designed to cover all the needs for data transfer between the detector and the data-acquisition system. It is a 1 Gbit/s, full-duplex, multi-purpose fibre optic link that can be used as a medium for the bi-directional transmission of data blocks between the front-end electronics and the data- acquisition system and also for the remote control and test of the front-end electronics, In this paper the concept, the protocol, the specific test tools, the prototypes of the detector data link and the read-out receiver card, their application in the ALICE-TPC test system and the integration with the DATE software are presented. The test results on the performance are also shown. (14 refs)
The ALICE DAQ: Current Status and Future Challenges
Proposal of abstract for CHEP2000The ALICE DAQ system has been designed to support an aggregate eventr building bandwidth of up to 2.5 GByte/s and a storage capability o fup to 1.25 GByte/s to mass storage.A general framework called the ALICE Data Acquisition Test Environment (DATE) system has been developed as a basis for prototyping the components of the DAQ. DATE supports a wide spectrum of configurations from simple systems to more complex systems with multiple detectors and multiple event builders.Prototypes of several key components of the ALICE DAQ have been developed and integrated with the DATE system, such as the ALICE Detector Data Link, the online data monitoring from ROOT and the interface to the Mass Storage systems. Combined tests of several of these components are pursued during the ALICE Data Challenges.The architecture of the ALICE DAQ system will be presented together with the current status of the different prototypes. The recent addition of a Transition Radiation Detector (TRD) to ALICE has required a revision of the requirements and the architecture of the DAQ. This will allow a higher level of data selection. These new opportunities and implementation challenges will also be presented
Deuteron and antideuteron production in Au+Au collisions at sqrt(s_NN)=200 GeV
The production of deuterons and antideuterons in the transverse momentum
range 1.1 < p_T < 4.3 GeV/c at mid-rapidity in Au + Au collisions at
sqrt(s_NN)=200 GeV has been studied by the PHENIX experiment at RHIC. A
coalescence analysis comparing the deuteron and antideuteron spectra with those
of protons and antiprotons, has been performed. The coalescence probability is
equal for both deuterons and antideuterons and increases as a function of p_T,
which is consistent with an expanding collision zone. Comparing (anti)proton
yields p_bar/p = 0.73 +/- 0.01, with (anti)deuteron yields: d_bar/d = 0.47 +/-
0.03, we estimate that n_bar/n = 0.64 +/- 0.04.Comment: 326 authors, 6 pages text, 5 figures, 1 Table. Submitted to PRL.
Plain text data tables for the points plotted in figures for this and
previous PHENIX publications are (or will be) publicly available at
http://www.phenix.bnl.gov/papers.htm
Mid-Rapidity Direct-Photon Production in p+p Collisions at sqrt(s) = 200 GeV
A measurement of direct photons in p+p collisions at sqrt(s)=200 GeV is
presented. A photon excess above background from pi^0 --> gamma+gamma, eta -->
gamma+gamma, and other decays is observed in the transverse momentum range 5.5
< p_T < 7 GeV/c. The result is compared to a next-to-leading-order perturbative
QCD calculation. Within errors, good agreement is found between the QCD
calculation and the measured result.Comment: 330 authors, 7 pages text, RevTeX, 2 figures, 2 tables. Submitted to
Physical Review D. Plain text data tables for the points plotted in figures
for this and previous PHENIX publications are (or will be) publicly available
at http://www.phenix.bnl.gov/papers.htm
Observation of direct-photon collective flow in sqrt(s_NN)=200 GeV Au+Au collisions
The second Fourier component v_2 of the azimuthal anisotropy with respect to
the reaction plane was measured for direct photons at midrapidity and
transverse momentum (p_T) of 1--13 GeV/c in Au+Au collisions at sqr(s_NN)=200
GeV. Previous measurements of this quantity for hadrons with p_T < 6 GeV/c
indicate that the medium behaves like a nearly perfect fluid, while for p_T > 6
GeV/c a reduced anisotropy is interpreted in terms of a path-length dependence
for parton energy loss. In this measurement with the PHENIX detector at the
Relativistic Heavy Ion Collider we find that for p_T > 4 GeV/c the anisotropy
for direct photons is consistent with zero, as expected if the dominant source
of direct photons is initial hard scattering. However, in the p_T < 4 GeV/c
region dominated by thermal photons, we find a substantial direct photon v_2
comparable to that of hadrons, whereas model calculations for thermal photons
in this kinematic region significantly underpredict the observed v_2.Comment: 384 authors, 6 pages, 3 figures, and 1 table. Submitted to Phys. Rev.
Lett. v2 has minor changes to match the submission version. Plain text data
tables for the points plotted in the figures are publicly available at
http://www.phenix.bnl.gov/phenix/WWW/info/data/ppg126_data.htm
Azimuthal anisotropy of pi^0 and eta mesons in Au+Au collisions at sqrt(s_NN)=200 GeV
The azimuthal anisotropy coefficients v_2 and v_4 of pi^0 and eta mesons are
measured in Au+Au collisions at sqrt(s_NN)=200 GeV, as a function of transverse
momentum p_T (1-14 GeV/c) and centrality. The extracted v_2 coefficients are
found to be consistent between the two meson species over the measured p_T
range. The ratio of v_4/v_2^2 for pi^0 mesons is found to be independent of p_T
for 1-9 GeV/c, implying a lack of sensitivity of the ratio to the change of
underlying physics with p_T. Furthermore, the ratio of v_4/v_2^2 is
systematically larger in central collisions, which may reflect the combined
effects of fluctuations in the initial collision geometry and finite viscosity
in the evolving medium.Comment: 384 authors, 71 institutions, 11 pages, 9 figures, and 2 tables.
Submitted to Physical Review C. Plain text data tables for the points plotted
in figures for this and previous PHENIX publications are (or will be)
publicly available at http://www.phenix.bnl.gov/papers.htm
Suppressed pi^0 Production at Large Transverse Momentum in Central Au+Au Collisions at sqrt(s_NN) = 200 GeV
Transverse momentum spectra of neutral pions in the range 1 < p_T < 10 GeV/c
have been measured at mid-rapidity by the PHENIX experiment at RHIC in Au+Au
collisions at sqrt(s_NN) = 200 GeV. The pi^0 multiplicity in central reactions
is significantly below the yields measured at the same sqrt(s_NN) in peripheral
Au+Au and p+p reactions scaled by the number of nucleon-nucleon collisions. For
the most central bin, the suppression factor is ~2.5 at p_T = 2 GeV/c and
increases to ~4-5 at p_T ~= 4 GeV/c. At larger p_T, the suppression remains
constant within errors. The deficit is already apparent in semi-peripheral
reactions and increases smoothly with centrality.Comment: 326 authors, 6 pages text, RevTeX, 3 figures, 2 tables. Submitted to
PRL. Plain text data tables for the points plotted in figures for this and
previous PHENIX publications are (or will be) publicly available at
http://www.phenix.bnl.gov/papers.htm
Scaling properties of proton and anti-proton production in sqrt(s_NN) = 200 GeV Au + Au collisions
We report on the yield of protons and anti-protons, as a function of
centrality and transverse momentum, in Au+Au collisions at sqrt(s_NN) = 200 GeV
measured at mid-rapidity by the PHENIX experiment at RHIC. In central
collisions at intermediate transverse momenta (1.5 < p_T < 4.5 GeV/c) a
significant fraction of all produced particles are protons and anti-protons.
They show a centrality-scaling behavior different from that of pions. The
p-bar/pion and p/pion ratios are enhanced compared to peripheral Au+Au, p+p,
and electron+positron collisions. This enhancement is limited to p_T < 5 GeV/c
as deduced from the ratio of charged hadrons to pi^0 measured in the range 1.5
< p_T < 9 GeV/c.Comment: 325 authors, 6 pages text, 4 figures, RevTeX 4. Minor changes to text
and figures to meet PRL length restrictions; no changes to figures;
resubmitted to PRL. Plain text data tables for the points plotted in figures
for this and previous PHENIX publications are (or will be) publicly available
at http://www.phenix.bnl.gov/papers.htm
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