Application of vertex and mass constraints in track-based alignment Amoraal, J.; Blouw, J.; Blusk, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2013, Letnik:
712
Journal Article
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The software alignment of planar tracking detectors using samples of charged particle trajectories may lead to global detector distortions that affect vertex and momentum resolution. We present an ...alignment procedure that constrains such distortions by making use of samples of decay vertices reconstructed from two or more trajectories and putting constraints on their invariant mass. We illustrate the method by using a sample of invariant-mass constrained vertices from D0→K−π+ decays to remove a curvature bias in the LHCb spectrometer.
•The ALEPH detector at LEP is used to measure cosmic ray muons.•Momentum spectrum and charge ratio of vertical muons at surface level are determined.•Results are compared to and interpreted by Monte ...Carlo models.•Information about energy spectrum and chemical composition of cosmic ray primaries is inferred.
The ALEPH detector at LEP has been used to measure the momentum spectrum and charge ratio of vertical cosmic ray muons underground. The sea-level cosmic ray muon spectrum for momenta up to 2.5TeV/c has been obtained by correcting for the overburden of 320m water equivalent (mwe). The results are compared with Monte Carlo models for air shower development in the atmosphere. From the analysis of the spectrum the total flux and the spectral index of the cosmic ray primaries is inferred. The charge ratio suggests a dominantly light composition of cosmic ray primaries with energies in the energy range between 103 and 105GeV.
Measurements of radiation effects in an antifuse FPGA Placinta, V.M.; Cojocariu, L.N.; Maciuc, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
October 2023, 2023-10-00, Letnik:
1055
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This paper presents the irradiation and the measurement analysis for a commercial antifuse Field Programmable Gate Array (FPGA) from Microsemi’s Axcelerator family, part number AX250. Following ...proton and X-ray beam irradiation, at very high dose rate above 1krad/s, the total ionizing dose (TID) first effects were visible around 260 krad (SiO 2), and this threshold value increases at lower radiation dose rates. We expect for most space and accelerator applications that this value will be at least several Mrads, or even that the FPGA might never reach this threshold. At very high radiation dose rates, TID-induced leakage currents were observed in the device. FPGA data were recorded continuously for more than 100 h after each irradiation with a fully operating FPGA. Quantitatively, the room-temperature annealing of the radiation-induced defects leads to a fast decrease of the device leakage current by a factor of 7 in the first 100 h after irradiation. The last measurements done after three months place the currents to within 30% to 70 % relative to the before-irradiation values in case of two tested FPGA. Several firmware configurations were used to test different logic resources and to measure single event upsets (SEUs). An upper limit of SEU logic cross-section was found to be (2.56 ± 0.51) ⋅ 10−13 cm 2/FPGA for dose rates around 1krad/s. SEU cross-section values for RAM blocks have on average a value of (3.72 ± 0.8) ⋅ 10−14 cm 2/bit. The complete list of results is given and the effects are extrapolated to a high-energy physics experiment environment — LHCb RICH at CERN.
The branching fractions of the decay Formula: see text for different intermediate states are measured using data, corresponding to an integrated luminosity of 1.0 fb
, collected by the LHCb ...experiment. The total branching fraction, its charmless component Formula: see text and the branching fractions via the resonant Formula: see text states
(1
) and
(2
) relative to the decay via a
/
intermediate state are Formula: see text Upper limits on the
branching fractions into the
(2
) meson and into the charmonium-like states
(3872) and
(3915) are also obtained.
The prompt production of the charmonium $\chi_{c1}$ and $\chi_{c2}$ mesons has been studied in proton-proton collisions at the Large Hadron Collider at a centre-of-mass energy of $\sqrt{s}=7$ TeV. ...The $\chi_c$ mesons are identified through their decays $\chi_c\to J/\psi\,\gamma$ with $J/\psi \to \mu^+ \mu^-$ using 36 $\mathrm{pb^{-1}}$ of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for the two $\chi_c$ spin states, $\sigma(\chi_{c2})/\sigma(\chi_{c1})$, has been determined as a function of the $J/\psi$ transverse momentum, $p_{\mathrm{T}}^{J/\psi}$, in the range from 2 to 15 GeV/$c$. The results are in agreement with the next-to-leading order non-relativistic QCD model at high $p_{\mathrm{T}}^{J/\psi}$ and lie consistently above the pure leading-order colour singlet prediction.
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