The DZERO level 3 data acquisition system

Rice University, Houston, Texas, United States
IEEE Transactions on Nuclear Science (Impact Factor: 1.46). 07/2004; DOI: 10.1109/TNS.2004.828785
Source: IEEE Xplore

ABSTRACT The DZERO experiment began RunII datataking operation at Fermilab in spring 2001. The physics program of the experiment requires the Level 3 data acquisition (DAQ) system system to handle average event sizes of 250 kilobytes at a rate of 1 kHz. The system routes and transfers event fragments of approximately 1-20 kilobytes from 63 VME crate sources to any of approximately 100 processing nodes. It is built upon a Cisco 6509 Ethernet switch, standard PCs, and commodity VME single board computers (SBCs). The system has been in full operation since spring 2002.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present measurements of the inclusive Drell-Yan e+e- differential cross section (dσ/dMe+e -) and forward-backward asymmetry (AFB ) as a function of the dielectron invariant mass over the range 70--400 GeV/c2. The data sample consists of 177.3 pb-1 of pp¯ collisions at s = 1.96 TeV collected by the DØ detector. The results are consistent with the predictions of the standard model.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Modern detectors used in high energy physics experiments are complex instruments designed to register collisions of particles at a rate in the MHz range. Data that correspond to a single collision of particles, referred to as an event, are acquired from millions of readout channels, and filtered, first by dedicated hardware, and then by computing farms running sophisticated filtering algorithms. In case of data acquisition systems with single-stage software filtration, due to the high input rate (the order of 100 kHz), the data are usually distributed in a static way between filtering nodes. However, the static distribution determines strongly the system, and results in decreased fault tolerance. The main objective of the presented studies is to increase the system's overall fault tolerance through dynamic load balancing. The proposed method aims to balance the workload inside heterogeneous systems, as well as, homogeneous systems, where the imbalance could be caused by faults. Moreover, our research includes developing a scalable load balancing protocol along with a distributed asynchronous load assignment policy. As a case study we consider the Data Acquisition system of the Compact Muon Solenoid experiment at CERN's new Large Hadron Collider.
    Parallel and Distributed Processing Workshops and Phd Forum (IPDPSW), 2011 IEEE International Symposium on; 06/2011
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A search for charged massive stable particles has been performed with the D0 detector using 1.1 fb{sup -1} of data. The speed of the particle has been calculated based on the time-of-flight and position information in the muon system. The present research is limited to direct pair-production of the charged massive long-lived particles. We do not consider CMSPs that result from the cascade decays of heavier particles. In this analysis, the exact values of the model parameters of the entire supersymmetric particle mass spectrum, relevant for cascade decays, are not important. We found no evidence of the signal. 95% CL cross-section upper limits have been set on the pair-productions of the stable scaler tau lepton, the gaugino-like charginos, and the higgsino-like charginos. The upper cross section limits vary from 0.31 pb to 0.04 pb, for stau masses in the range between 60 GeV and 300 GeV. We use the nominal value of the theoretical cross section to set limits on the mass of the pair produced charginos. We exclude the pair-produced stable gaugino-like charginos with mass below 206 GeV, and higgsino-like charginos below 171 GeV, respectively. Although the present sensitivity is insufficient to test the model of the pair produced stable staus, we do set cross section limits which can be applied to the pair production of any charged massive stable particle candidates with similar kinematics. These are the most restrictive limits to the present on the cross sections for CMSPs and the first published from the Tevatron Collider Run II. The manuscript has been published by Physical Review Letters in April 2009 and is available at arXiv as.


Available from