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 B 0 s π ± invariant mass distribution is investigated in order to search for possible exotic meson states. The analysis is based on a data sample recorded with the LHCb detector corresponding to ...3 fb − 1 of p p collision data at √ s = 7 and 8 TeV. No significant excess is found, and upper limits are set on the production rate of the claimed X ( 5568 ) state within the LHCb acceptance. Upper limits are also set as a function of the mass and width of a possible exotic meson decaying to the B 0 s π ± final state. The same limits also apply to a possible exotic meson decaying through the chain B * 0 s π ± , B * 0 s → B 0 s γ where the photon is excluded from the reconstructed decays.
The CP violation observables S and C in the decay channel B0→D+D− are determined from a sample of proton-proton collisions at centre-of-mass energies of 7 and 8 TeV, collected by the LHCb experiment ...and corresponding to an integrated luminosity of 3 fb−1. The observable S describes CP violation in the interference between mixing and the decay amplitude, and C parametrizes direct CP violation in the decay. The following values are obtained from a flavour-tagged, decay-time-dependent analysis:SC=−0.54+0.17−0.16(stat)±0.05(syst),=0.26+0.18−0.17(stat)±0.02(syst).These values constrain higher-order Standard Model corrections to be small.
Data from a dedicated cosmic ray run of the ALEPH detector were used in a study of muon trident production, i.e., muon pairs produced by muons. Here the overburden and the calorimeters are the target ...materials while the ALEPH time projection chamber provides the momentum measurements. A theoretical estimate of the muon trident cross section is obtained by developing a Monte Carlo simulation for muon propagation in the overburden and the detector. Two muon trident candidates were found to match the expected theoretical pattern. The observed production rate implies that the nuclear form factor cannot be neglected for muon tridents.
This work includes measurements of the single event effects and cumulative effects induced in the antifuse FPGA by radiation. Several FPGAs were irradiated with 24 MeV protons and X-rays. During ...irradiations, the dose rate values were between 0.1 and 1 krad/s and the maximum value of the total ionization dose was 8 Mrad. For these dose rates, the radiation-induced leakage currents were observed in the FPGA power consumption. This induced leakage current was measured above a non-fixed threshold which depends on dose rate. At a very high dose rate of 1 krad/s, the threshold value is about 260 krad. We have also measured a very fast room-temperature annealing process. With the FPGA operating continuously after the beam exposure, the annealing process restored the core current in one FPGA from 470 mA to 60 mA in about 38 hours. During the first 3-4 months after irradiation, the core current continued the descending trend, and the relative difference with respect to the current before irradiation shrinks to 30%-50%. Using dedicated firmware, the FPGA logic resources (Flip-Flops, RAM Blocks, and I/O blocks) were monitored for single event effects. Only in the most extreme conditions tested, a low number of logic errors (3 errors) was found for a fluence of (2.5 ± 0.5) * 10 13 protons/cm 2 , hence the upper limit of the cross-section was computed to be 2.6 * 10 -13 cm 2 /DUT. The RAM resources were determined to be prone to single-event upsets, and the cross-section value was determined to be (3.72 ± 0.8) * 10 -14 cm 2 /bit. The FPGA will operate with no visible effects in a typical radiation environment from space or high-energy physics experiments. The expected dose rates for experiments are on order of 0.1 rads/s, and any effects will be mitigated through a rapid room-temperature annealing process.
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