Review and prospects of the CASCADE data acquisition system at CERN

CASCADE, a multi-processor real-time data-acquisition system for HEP experiments developed at CERN by the ECP-DS group, has now been in operation for one year. The current implementation supports configurations based on VMEbus processors running OS-9 and on UNIX workstations interconnected via VICbus or Ethernet. The project is reviewed by describing the main characteristics of the package, the applications in which it has been used, and the results of this experience. The main improvements of 1994, which include a parameterized multi-level event builder, a remote monitoring option and a powerful run control facility, as well as ongoing developments and prospects for 1995, are presented

The ROD crate DAQ software framework of the ATLAS data acquisition system

In the ATLAS experiment at the LHC, the ROD Crate DAQ provides a complete software framework to implement data acquisition functionality at the boundary between the detector specific electronics and the common part of the data acquisition system. Based on a plugin mechanism, it allows selecting and using common services (like data output and data monitoring channels) and developing software to control and acquire data from detector specific modules providing the infrastructure for control, monitoring and calibration. Including also event building functionality, the ROD Crate DAQ is intended to be the main data acquisition tool for the first phase of detector commissioning. This paper presents the design, functionality and performance of the ROD Crate DAQ and its usage in the ATLAS data acquisition system and during detector tests

Integration of VICbus, FDL, SCI and Ethernet in the CERN CASCADE data acquisition system

Cascade is a multi-processor real-time data-acquisition system for HEP experiments developed at CERN by the ECP-DS group. Configurations supported today include VMEbus processors running OS-9 and UNIX workstations. The CASCADE data acquisition processes, called stages communicate via links, at present VICbus between VME crates and Ethernet between VMEbus processors and workstations. Work is in progress to introduce new inter-stage links based on the Fast Data Link between VME crates and on SCI for data exchange between SUN stations. The paper gives a short description of the architecture of CASCADE with emphasis on the link aspects. The implementation and current status of the inter-stage links based on VICbus, Ethernet, FDI, and SCI will be described and results on the performances presented

Experience with fibre channel in the environment of the ATLAS DAQ protoype "-1" project

Fibre Channel equipment has been evaluated in the environment of the ATLAS DAQ prototype "-1". Fibre Channel PCI and PMC cards have been tested on PwerPC-based VME processor boards running LynxOS and on Pentium-based personal computers running Windows NT. The performance in terms of overhead and bandwidth has been measured in point-to-point, arbitrated loop and fabric configuration with a Fibre Ch annel switch. The possible used of the equipment for event building in the ATLAS DAQ prototype "-1" has been studied

Using Linux PCs in DAQ applications

ATLAS Data Acquisition/Event Filter "-1" (DAQ/EF1) project provides the opportunity to explore the use of commodity hardware (PCs) and Open Source Software (Linux) in DAQ applications. In DAQ/EF-1 there is an element called the LDAQ which is responsible for providing local run-control, error-handling and reporting for a number of read- out modules in front end crates. This element is also responsible for providing event data for monitoring and for the interface with the global control and monitoring system (Back-End). We present the results of an evaluation of the Linux operating system made in the context of DAQ/EF-1 where there are no strong real-time requirements. We also report on our experience in implementing the LDAQ on a VMEbus based PC (the VMIVME-7587) and a desktop PC linked to VMEbus with a Bit3 interface both running Linux. We then present the problems encountered during the integration with VMEbus, the status of the LDAQ implementation and draw some conclusions on the use of Linux in DAQ applications. (18 refs)

Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector

The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +c¯¯)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−s¯¯¯ quark asymmetry

Inclusive search for same-sign dilepton signatures in pp collisions at root s=7 TeV with the ATLAS detector

An inclusive search is presented for new physics in events with two isolated leptons (e or mu) having the same electric charge. The data are selected from events collected from p p collisions at root s = 7 TeV by the ATLAS detector and correspond to an integrated luminosity of 34 pb(-1). The spectra in dilepton invariant mass, missing transverse momentum and jet multiplicity are presented and compared to Standard Model predictions. In this event sample, no evidence is found for contributions beyond those of the Standard Model. Limits are set on the cross-section in a fiducial region for new sources of same-sign high-mass dilepton events in the ee, e mu and mu mu channels. Four models predicting same-sign dilepton signals are constrained: two descriptions of Majorana neutrinos, a cascade topology similar to supersymmetry or universal extra dimensions, and fourth generation d-type quarks. Assuming a new physics scale of 1 TeV, Majorana neutrinos produced by an effective operator V with masses below 460 GeV are excluded at 95% confidence level. A lower limit of 290 GeV is set at 95% confidence level on the mass of fourth generation d-type quarks

Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

A measurement of the production cross-section for top quark pairs(\ttbar) in $pp$ collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron $e$ or muon $\mu$) with large missing transverse energy and at least four jets, and dilepton ($ee$, $\mu\mu$ or $e\mu$) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be $12.2 \pm 3.9$ events and $2.5 \pm 0.6$ events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde