In this paper, we consider a
generalized formulation of a quasistatic frictional contact problem for a material point, subject to a system of linear springs and constrained to remain in a half plane. ...The unilateral Signorini law and the Coulomb law of friction govern the contact with the boundary of the forbidden region. The formulation we consider here is
generalized, because it is given in terms of a variable different from the original time variable. The new variable (arc-length type) allows us to spread out the behavior of the system along time discontinuities that are expected in this kind of problem (in terms of the new variable, the solution is absolutely continuous). The mathematical formulation is given by means of a differential inclusion, which admits branches of solutions. Among them, assuming that the applied force does not oscillate with infinite frequence, it is possible to select one that will make it possible to reconstruct a solution to the mechanical problem.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The J-PARC T59 experiment, named WAGASCI, has been developing a neutrino detector to measure a cross section ratio of charged current interaction on nucleus between water and plastic targets with ...uncertainties of a few percent at the J-PARC neutrino beamline. The WAGASCI detector adopts three-dimensional grid structure of 3mm-thick plastic scintillator bars around water target, to perform three-dimensional reconstruction of a particle trajectory, to improve the acceptance for large angle tracks. The light from scintillator is read out by MPPCs. An array of 32-channel MPPCs has been newly developed for this experiment. The total number of channels for the WAGASCI detector is 1280. The SPIROC2D ASIC chip, developed by OMEGA, has been employed in the frontend electronics. SPIROC2D is an auto-triggered, bi-gain, 36-channel ASIC, allowing the measurement of the charge from one to 2000 photoelectrons and the time with 100ps resolution. It contains a 16-deep analog memory array, which allows 16 hits to be stored in an acquisition gate. The backend electronics utilize Spartan6 FPGAs. The system to synchronize the data acquisition to the beam timing from J-PARC has been also developed and the data acquisition system has also been developed. The data taking with neutrino beam has started since autumn October 16, 2017.
Recent results from the Front-End electronics of the Detector of Internally Reflected Cerenkov light (DIRC) for the BaBar experiment at SLAC (Stanford, USA) are presented. It measures to better than ...1 ns the arrival time of Cerenkov photoelectrons detected in a 11000 phototubes array and their amplitude spectra. It mainly comprises 64-channel DIRC Front-End Boards (DFB) equipped with eight full-custom analog chips performing zero-cross discrimination with 2 mV threshold and pulse shaping, four full-custom digital time to digital chips (TDC) for timing measurements with 500 ps binning and a readout logic selecting hits in the trigger window, and DIRC Crate Controller cards (DCC) serializing the data collected front up to 16 DFBs onto a 1.2 Gb/s optical link. Extensive test results of the pre-production chips are presented, as well as system tests.
The DIRC front-end electronics chain for BaBar Bailly, P.; Chauveau, J.; Buono, L.Del ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/1999, Volume:
433, Issue:
1
Journal Article
Peer reviewed
The detector of Internally Reflected Cherenkov light (DIRC) of the BaBar detector (SLAC Stanford, USA) measures better than 1
ns the arrival time of Cherenkov photoelectrons, detected in a 11
000 ...phototubes array and their amplitude spectra. It mainly comprises of 64-channel DIRC Front-End Boards (DFB) equipped with eight full-custom Analog chips performing zero-cross discrimination with 2 mV threshold and pulse shaping, four full-custom Digital TDC chips for timing measurements with 500 ps binning and a readout logic selecting hits in the trigger window, and DIRC Crate Controller cards (DCC) serializing the data collected from up to 16 DFBs onto a 1.2 Gb/s optical link. Extensive test of the pre-production chips have been performed as well as system tests.
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IJS, IMTLJ, KILJ, KISLJ, NUK, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The DIRC, a new type of ring-imaging Cherenkov detector that images internally reflected Cherenkov light, is being constructed as the main hadronic particle identification component of the BABAR ...detector at SLAC. The device makes use of 5 meter long fused silica (colloquially called quartz) bars, which serve both as the Cherenkov radiators and as light pipes for transmitting the light to an array of photo-multiplier tubes. This paper describes a program of research and development-aimed at determining whether bars that meet the stringent requirements of the DIRC can be obtained from commercial sources. The results of studies of bulk absorption of fused silica, surface finish, radiation damage and bulk inhomogeneities are discussed
The Front-End electronics of the Detector of Internally Reflected Cerenkov light (DIRC) for the BaBar experiment is presented. Its aim is to measure to better than 1 ns the arrival time of Cerenkov ...photoelectrons, detected in a 11000 phototubes array and their amplitude spectra. It mainly comprises 64-channel DIRC Front-End Boards (DFB) equipped with eight full-custom analog chips performing zero-cross discrimination with 2 mV threshold and pulse shaping, four full-custom digital TDC chips for timing measurements with and a readout logic selecting hits in the trigger window, and DIRC Crate Controller cards (DCC) serializing the data collected from up to 16 DFBs onto a 1.2 Gb/s optical link. Extensive test results of the pre-production chips are presented, as well as system tests.
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