0000000000263062
AUTHOR
W. Bell
showing 6 related works from this author
Abstracts of the 6th FECS Conference 1998 Lectures.
1998
International audience
Luminosity determination in pp collisions at s=7 TeV using the ATLAS detector at the LHC
2011
Measurements of luminosity obtained using the ATLAS detector during early running of the Large Hadron Collider (LHC) at s√=7 TeV are presented. The luminosity is independently determined using several detectors and multiple algorithms, each having different acceptances, systematic uncertainties and sensitivity to background. The ratios of the luminosities obtained from these methods are monitored as a function of time and of μ, the average number of inelastic interactions per bunch crossing. Residual time- and μ-dependence between the methods is less than 2% for 0<μ<2.5. Absolute luminosity calibrations, performed using beam separation scans, have a common systematic uncertainty of ±11%, do…
Cryogenic operation of silicon detectors
2000
This paper reports on measurements at cryogenic temperatures of a silicon microstrip detector irradiated with 24 GeV protons to a #uence of 3.5]1014 p/cm2 and of a p}n junction diode detector irradiated to a similar #uence. At temperatures below 130 K a recovery of charge collection e$ciency and resolution is observed. Under reverse bias conditions this recovery degrades in time towards some saturated value. The recovery is interpreted qualitatively as
Production and investigation of multiply charged metal clusters in a Penning trap
1996
Singly charged gold cluster ions from a laser-vaporization source are transferred into a Penning trap and subjected to electron bombardment. The charged reaction products are analyzed by time-of-flight mass spectrometry after axial ejection from the trap. They include singly charged cluster fragments, multiply charged clusters of the initial size and multiply charged cluster fragments. The multiply charged clusters are selected and further investigated by collision induced dissociation. Two types of reactions can be distinguished: Dissociation into several charged fragments and evaporation of neutrals. Several features of multiply charged clusters relevant for future investigations are revi…
Study of the leptonic decays of the Z0 boson
1990
Measurements are presented of the cross section ratios Rℓ = σℓ(e+e-→ℓ+ℓ -)/σhh(e+e-→hadrons) for ℓ = e, μ and τ using data taken from a scan around the Z0. The results are Re = (5.09±0.32±0.18)%, Rμ = (4.96±0.35±0.17)% and Rτ,=(4.72±0.38± 0.29)% where, for the ratio Re, the t-channel contribution has been subtracted. These results are consistent with the hypothesis of lepton universality and test this hypothesis at the energy scale s ∼ 8300 GeV2. The absolute cross sections σℓ(e+e-→ℓ +ℓ-) have also been measured. From the cross sections the leptonic partial widths Γe = (83.2±3.0±2.4) MeV, (ΓeΓμ) 1/2=(84.6±3.0±2.4) MeV and (ΓeΓτ) 1/2=(82.6±3.3±3.2) MeV have been extracted. Assuming lepton un…
Charge collection efficiency and resolution of an irradiated double-sided silicon microstrip detector operated at cryogenic temperatures
1999
Abstract This paper presents results on the measurement of the cluster shapes, resolution and charge collection efficiency of a double-sided silicon microstrip detector after irradiation with 24 GeV protons to a fluence of 3.5×10 14 p/cm 2 and operated at cryogenic temperatures. An empirical model is presented which describes the expected cluster shapes as a function of depletion depth, and is shown to agree with the data. It is observed that the clusters on the p-side broaden if the detector is under-depleted, leading to a degradation of resolution and efficiency. The model is used to make predictions for detector types envisaged for the LHC experiments. The results also show that at cryo…