Abstract
The SHiP experiment has been proposed at CERN to shed light
on phenomena still unexplained in the framework of the Standard
Model, such as the nature of dark matter, the baryonic asymmetry ...of
the Universe and the neutrino oscillations, searching for hints of
New Physics. A section of the detector will be dedicated to the
study of neutrino physics with special emphasis on tau neutrino
properties, still very poorly measured. A system to identify the
muons produced in neutrino interactions, based on RPC technology,
has been proposed and it is presented in detail in this paper.
The RPC trigger system of the F/B muon spectrometer at the L3 experiment Aloisio, A; Alviggi, M.G; Carlino, G ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/1996, Letnik:
379, Številka:
3
Journal Article
Recenzirano
The L3 experiment has recently been upgraded with a Forward-Backward muon spectrometer in view of the LEP 200 physics. Due to their high efficiency and good time resolution, Resistive Plate Counters ...(RPCs) where chosen for building a system providing the muon trigger in that region. The detector has been successfully built and installed, and the expected performances are confirmed.
An ageing test of three ATLAS production RPC stations is in progress at X5 GIF, the CERN irradiation facility. The chamber efficiency as a function of the operating voltage is measured at different ...source intensities, up to a maximum counting rate of about 700 Hz/cm/sup 2/. All along the test, plate resistivity has been monitored using two different methods: by measuring the I-V characteristics in pure Ar, and by comparing the efficiency vs high voltage curves at different source intensities. The increase in plate resistivity, which is one of the dominant ageing effects for RPCs with phenolic-melaminic electrodes, has been shown to be strongly dependent on environmental relative humidity. Indeed, after setting to values between 40% and 50% the relative humidity of both the operating gas and the air surrounding the chambers, a significant decrease of the plate resistivity has been observed.
Resistive plate chambers will be used as trigger detectors in the barrel region of the muon spectrometer of the ATLAS experiment at the LHC. The total number of RPC units to be installed is greater ...than 1000, covering a total surface of about 3650 m/sup 2/. Three cosmic rays test stands have been designed and built in Naples, Lecce and Rome "Tor Vergata" INFN laboratories in order to carry out the quality assurance tests on the ATLAS RPCs. Although the three test stands are based on different setups and use different techniques to trigger and to reconstruct cosmic rays, the same tests are performed, in order to have the same quality criteria. Since august 2002 more than 600 units have been tested, mainly in the Naples site. This large number of RPC units tested allows to perform a statistical evaluation of the uniformity and stability of the main RPC performance characteristics over such a large scale production. Most of the tested RPCs satisfied the required specifications and only a small fraction of them had to be rejected.
In this Report, QCD results obtained from a study of hadronic event structure in high energy
e
+
e
-
interactions with the
L3 detector are presented. The operation of the
LEP collider at many ...different collision energies from 91 to 209
GeV offers a unique opportunity to test QCD by measuring the energy dependence of different observables. The main results concern the measurement of the strong coupling constant,
α
s
, from hadronic event shapes and the study of effects of soft gluon coherence in charged particle multiplicity and momentum distributions.
The ATLAS level-1 muon trigger will be crucial for the online selection of events with high transverse momentum muons and for its correct association to the bunch-crossing corresponding to the ...detected events. This system uses dedicated coarse granularity and fast detectors capable of providing measurements in two orthogonal projections. The resistive plate chambers (RPCs) are used in the barrel region (|/spl eta/| < 1). The associated trigger electronics is based on a custom chip, the coincidence matrix, that performs space coincidences within programmable roads and time gates. The system is highly redundant and communicates with the ATLAS level-1 trigger processor with the MUCTPI interface. The trigger electronics provides also the readout of the RPCs. Preliminary results achieved with a full trigger tower with production detectors in the H8 test beam at CERN will be shown, in particular preliminary results on the integration of the barrel muon trigger electronics with the MUCTPI interface and with the ATLAS DAQ system will be discussed.
Single- and multi-photon events with missing energy are selected in 619 pb−1 of data collected by the L3 detector at LEP at centre-of-mass energies between 189 and 209 GeV. The cross sections of the ...process e+e−→νν̄γ(γ) are found to be in agreement with the Standard Model expectations, and the number of light neutrino species is determined, including lower energy data, to be Nν=2.98±0.05±0.04. Selection results are given in the form of tables which can be used to test future models involving single- and multi-photon signatures at LEP. These final states are also predicted by models with large extra dimensions and by several supersymmetric models. No evidence for such models is found. Among others, lower limits between 1.5 and 0.65 TeV are set, at 95% confidence level, on the new scale of gravity for the number of extra dimensions between 2 and 6.
We have measured the cosmic ray absolute flux and its variations caused by "day-night" and "barometric" effect, for the first time in the Naples area,, by using a telescope of resistive plate chamber ...(RPC) detectors. Because of the high sensitivity needed for this measure, the RPC behaviour must be very well controlled and all the influences induced by the environmental parameters, must be compensated. For this purpose we introduced, among others features, an alternative method for the stabilization of the RPC working point. We present here all the results for both aspects: the cosmic ray flux measurements, the barometric effect and a description of the RPC stabilization method used.
The mass and the total decay width of the W boson are measured with the L3 detector at the LEP e+e– collider using W-boson pairs produced in 0.7 fb–1 of data collected at centre-of-mass energies ...between 161 and 209 GeV. Combining semi-leptonic and fully-hadronic final states, the mass and the width of the W boson are determined to be where the first uncertainty is statistical and the second systematic.
A 13-inch Optical Module (OM) containing a large-area (10-inch) photomultiplier was designed as part of Phase-2 of the NEMO project. An intense R&D activity on the photomultipliers, the voltage ...supply boards, the optical coupling as well as the study of the influences of the Earth's magnetic field has driven the choice of each single component of the OM. Following a well-established production procedure, 32 OMs were assembled and their functionality tested. The design, the testing and the production phases are thoroughly described in this paper.
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