We have measured the response of an array of monitored drift tubes (MDT) to fast neutrons produced by a t(d,n)/sup 4/He reaction at the TANDEM Van de Graaff accelerator of the National Center of ...Scientific Research (NCSR) "Demokritos". The MDT setup consisted of 24 drift tubes operating with a gas mixture of ArCO/sub 2/ (93:7%) at 3 bar absolute pressure. The neutron energy was 18.3 MeV. The operating anode wire voltage varied from 2200 V to 2800 V. The PC based data acquisition system was self-triggered by the OR of all 24 MDT. Data were also taken by triggering on a single tube. The data analysis is presented and the response of the MDT detector to energetic neutrons is discussed with emphasis on the determination of the MDT sensitivity to neutrons.
Motivated by the high muon momentum resolution and identification efficiency achievable with the ATLAS detector, currently being installed at CERN, we explore the observability of the supersymmetric ...h/A/H decays to two muons. The high experimental resolution in this decay mode compensates to some extent for the suppression of the branching ratio, with respect to the h/A/H → τ τ decays. The search is performed in a wide Higgs mass range, starting from 110 GeV/c2. In the case of gg → bb(h/H/A) production mode, the additional b-jets produced in association with the h/H/A bosons are used to suppress the background. Using fully simulated signal and background event samples, we study the performance of the reconstruction algorithms relevant to the analysis, such as the muon reconstruction, b-tagging and the measurement of the missing energy. The influence of the detector misalignment on the reconstruction performance is also taken into consideration. Emphasis is given on the optimization of the event selection procedure and the corresponding selection criteria, taking into account the different background composition depending on the mass range in which the Higgs search is performed.
Measurement of Muon Energy Loss in ATLAS Nikolopoulos, K.; Fassouliotis, D.; Kourkoumelis, C. ...
2006 IEEE Nuclear Science Symposium Conference Record,
2006-Oct., Letnik:
1
Conference Proceeding
The ATLAS muon spectrometer is designed to provide precise momentum measurement for muons up to O(1 TeV/c). The fluctuations in the energy loss of muons in the material downstream of the muon ...spectrometer could deteriorate the physics performance, which requires the momentum to be expressed at the interaction point. A method to account for this energy loss using the calorimeter measurement is presented. The method provides an estimation of the energy loss on an event-by-event basis thus reducing the statistical fluctuations. The momentum resolution is optimized with significant suppression of the non-Gaussian tails as it is demonstrated using simulated single muon data. The performance of the method on physics samples with several muons in the final state, is also briefly described.
In order to benefit from the expected increase in luminosity of the upgraded LHC accelerator, the innermost station in the forward region of the ATLAS Muon Spectrometer will be replaced by the New ...Small Wheel, (NSW) currently under construction. NSW features two new detector technologies (resistive Micromegas detectors, (MM) and small strip Thin Gap Chambers, (sTGC)) comprising ~ 2.4 × 10 6 readout channels. The large number of readout channels, the high data rates and the harsh conditions, under which the NSW will operate, pose significant challenges to its trigger and data acquisition system. The Level-1 Data Driver Card (L1DDC) boards are part of the on NSW detector electronics and mainly consist of high radiation and magnetic field tolerant custom made ASICs. Three different types of L1DDC boards have been developed; two for the readout chain of the MMs and sTGCs and one for the trigger electronics chain of the sTGCs. Over 97% of the 1184 L1DDC boards (572 for the MM and 612 for the sTGC detector technologies) that have been tested at four testing sites are found to operate according to their specifications.
The photon radiation in the initial state lowers the energy available for the e
+e
− collisions; this effect is particularly important at LEP2 energies (above the mass of the
Z boson). Being aligned ...to the beam direction, such initial state radiation is mostly undetected. This article describes the procedure used by the DELPHI experiment at LEP to estimate the effective centre-of-mass energy in hadronic events collected at energies above the
Z peak. Typical resolutions ranging from 2 to 3
GeV on the effective center-of-mass energy are achieved, depending on the event topology.
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