120183131
ATLAS LIQUID ARGON HADRONIC CALORIMETERS
The ATLAS experiment is a general purpose detector designed to exploit the full potential of the Large Hadron Collider at both low and high luminosity running. Central to the ATLAS physics program is what one can term discovery physics. In defining the calorimeter design goals this discovery physics has been a major consideration. An important design touchstone was the ability to discover a standard model Higgs over a wide mass range. This is shown in Fig.1. At low masses the energy resolution for photons, and fine electromagnetic spatial resolution, are at a premium in order to distinguish photons from 0 π and to reconstruct the channel H γγ → against a large background; this sets the design goals for the electromagnetic calorimeter system. In the intermediate mass region the decay channel H l l l l + − + − → again mandates high quality electromagnetic calorimetry over a wide rapidity range. In the high mass region up to 1 TeV, the ability to identify jets and to reconstruct jet invariant masses is a major design consideration. Many “discovery” topics, such as supersymmetery, depend on the detection of missing energy and require hermetic hadronic calorimetry. These are only the major design goals, and clearly more optimization than can be covered here has gone on in the design of ATLAS, see [1]. A summary of the calorimeter design goals, and the chosen technologies is given in Fig. 2. At this meeting the construction and testing of the electromagnetic calorimeters was covered in separate contributions, see [2], [3]. Here we restrict ourselves to a discussion of the Forward Calorimeter, the assembly of the end cap calorimeters, and plans for combined test beams.
108443384
Design and development of tungsten-liquid argon modules for the ATLAS forward calorimeter system
The design of a tungsten-liquid argon calorimeter for the high |η| region of the ATLAS detector at the LHC is discussed. A novel design using hexagonally packed, tubular, thin gap electrodes running parallel to the beam direction is employed. The absorber matrix is composed of small “slugs” of sintered tungsten alloy. To test the mechanical design and construction methodology, a small engineering prototype, or “maquette”, has been constructed. This maquette is a full featured, full depth device, deviating from the final production modules only in lateral size.
24278126
Performance of the ATLAS liquid argon forward calorimeter in beam tests
One of two ATLAS Forward Calorimeters, consisting of three modules, one behind the other, was exposed to particle beams of known energies in order to study the detector performance with and without the presence of upstream material in the beam, and at the inner edge of the acceptance where shower energy containment is incomplete. Data were taken in the H6 beamline at CERN using electron and hadron beams with energies from 10 to 200 GeV. Results related to the intrinsic detector calibration, based on data taken with a minimal amount of material in front of the detector, have been previously published, but are updated here. This paper focuses on studies of data taken with additional upstream material in place. The effects of this additional material on the linearity and resolution of the response are presented. The response at the inner edge of the acceptance is also investigated. For all analyses, results based on a GEANT4 simulation of the beam-test setup and detector response are also presented.
117400633
A proposal for a preliminary beam survey in the 3.5 mrad beam
We propose to measure the yields of positive and negative pions, kaons, and nucleons at 200 GeV/c from several target materials in the 3.5 mrad beam of the Meson Laboratory.
123836660
THREE BODY DECAYS OF NEUTRAL K MESONS.
123565642
Dimuon Production by Neutrons
A very narrow resonance with a mass of 3.1 GeV/c2 is observed in the reaction n+Be→μ++μ-+X. The total cross section for this process, as well as its P⊥2 and x distribution, are given.
119851490
Photoproduction of narrow resonances
A very narrow resonance with a mass of 3.105 GeV/${\mathit{c}}^{2}$ is observed in the reaction $\ensuremath{\gamma}+\mathrm{Be}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}+{\ensuremath{\mu}}^{\ensuremath{-}}+X$. The total cross section for this process, as well as its $t$ distribution, is given.