ATLAS Muon Chamber Construction Parameters for CSC, MDT, and RPC chambers

This paper describes the construction parameters of the Cathode Strip Chambers (CSC), Monitored Drift Tube (MDT) chambers, and the Resistive Plate Chambers (RPC) of the ATLAS Muon Spectrometer

A spark-resistant bulk-micromegas chamber for high-rate applications

We report on the design and performance of a spark-resistant bulk-micromegas chamber. The principle of this design lends itself to the construction of large-area muon chambers for the upgrade of the detectors at the Large Hadron Collider at CERN for luminosities in excess of 10**34/cm2/s or other high-rate applications.Comment: 12 pages, 13 figure

On TPC cluster reconstruction

For a bias-free momentum measurement of TPC tracks, the correct determination of cluster positions is mandatory. We argue in particular that (i) the reconstruction of the entire longitudinal signal shape in view of longitudinal diffusion, electronic pulse shaping, and track inclination is important both for the polar angle reconstruction and for optimum r phi resolution; and that (ii) self-crosstalk of pad signals calls for special measures for the reconstruction of the z coordinate. The problem of 'shadow clusters' is resolved. Algorithms are presented for accepting clusters as 'good' clusters, and for the reconstruction of the r phi and z cluster coordinates, including provisions for 'bad' pads and pads next to sector boundaries, respectively

Water data: bad TPC pads, 3.6 µs and 100 ns problems

Out of the 3972 pads of the HARP TPC, about 9% are 'bad' and not useful for the correct reconstruction of clusters. Bad pads comprise dead pads, noisy pads, and pads with low or undefined amplification. Pads may be bad at one time, but not at another. This memo discusses the sources of information which were used to declare a pad 'bad', and gives the list of bad pads for the water data (runs 19146 to 19301). Also, the 3.6 µs and 100 ns problems of the TPC readout are discussed, including the corrective measures which have been taken

Performance of TPC crosstalk correction

The performance of the CERN-Dubna-Milano (CDM) algorithm for TPC crosstalk correction is presented. The algorithm is designed to correct for uni-directional and bi-directional crosstalk, but not for self-crosstalk. It reduces at the 10% level the number of clusters, and the number of pads with a signal above threshold. Despite of dramatic effects in selected channels with complicated crosstalk patterns, the average longitudinal signal shape of a hit, and the average transverse signal shape of a cluster, are little affected by uni-directional and bi-directional crosstalk. The longitudinal signal shape of hits is understood in terms of preamplifier response, longitudinal diffusion, track inclination, and self-crosstalk. The transverse signal shape of clusters is understood in terms of the TPC's pad response function. The CDM crosstalk correction leads to an average charge decrease at the level of 15%, though with significant differences between TPC sectors. On the whole, crosstalk constitutes a relatively benign malfunction of the TPC readout which, after correction by the CDM algorithm and with proper attention to self-crosstalk, is not an obstacle to progress with physics analysis

Assembly and Certification of ATLAS Muon Stations for the Middle and Outer Barrel at CERN

Roughly 400 of the approximately 700 muon stations of the ATLAS barrel belong to the middle and outer layer. Barrel Middle and Barrel Outer stations consist of both an MDT chamber and one or two RPC planes delivering the level-1 trigger information. While MDT chambers and individual RPC units are constructed at their home institutes, the assembly of the RPCs into planes, including the final cabling and the mounting of the trigger electronics, as well as the integration of MDTs and RPCs into muon stations takes place at CERN. MDT chambers, RPC planes and the completed stations have to pass a series of tests before being declared 'ready-for-installation'. Final certification criteria is the passing of a one-day cosmic ray test, for which a special setup has been built in building 899 (BB5). This note gives an overview over the work carried out in BB5, with emphasis on the cosmic ray test. Examples of abnormal chamber behavior will be discussed and a summary of common mistakes in station assembly or chamber cabling will be given. A second focus of the note is on the statistical analysis of the certification results

Water data analysis: data reduction from beam and ITC info

After recalling the motivation for the analysis of water data, the first stage of data reduction is discussed. This data reduction is based on the selection of protons using beam detector data and ITC information. The resolution of the interaction time in the target which serves as reference for time-of-flight measurement of secondaries, is determined with stable beam optics to be 77 ps, otherwise 106 ps. Cuts, their selection efficiency, event numbers, purity of the data sample after cuts, and some ITC characteristics are presented

Revisiting the 'LSND anomaly' II: critique of the data analysis

This paper, together with a preceding paper, questions the so-called 'LSND anomaly': a 3.8 sigma excess of antielectronneutrino interactions over standard backgrounds, observed by the LSND Collaboration in a beam dump experiment with 800 MeV protons. That excess has been interpreted as evidence for the antimuonneutrino to antielectronneutrino oscillation in the \Deltam2 range from 0.2 eV2 to 2 eV2. Such a \Deltam2 range is incompatible with the widely accepted model of oscillations between three light neutrino species and would require the existence of at least one light 'sterile' neutrino. In a preceding paper, it was concluded that the estimates of standard backgrounds must be significantly increased. In this paper, the LSND Collaboration's estimate of the number of antielectronneutrino interactions followed by neutron capture, and of its error, is questioned. The overall conclusion is that the significance of the 'LSND anomaly' is not larger than 2.3 sigma.Comment: 30 pages, 16 figures, 6 table

Reply to 'Corrections to the HARP-CDP Analysis of the LSND Neutrino Oscillation Backgrounds'

The alleged mistakes in recent papers that reanalyze the backgrounds to the 'LSND anomaly' do not exist. We maintain our conclusion that the significance of the 'LSND anomaly' is not 3.8 sigma but not larger than 2.3 sigma.Comment: 3 page