4,086 research outputs found

    The system of EAS time analysis

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    The extensive air showers' (EAS) front shape, angle of incidence, disk thickness, particle distribution along the shower, on the delayed and EAS front advancing particles were determined. The suggested system of the EAS time analysis allows determination of the whole EAS longitudinal structure at the observation points. The information from the detectors is continuously recorded in the memory with the memory cell switching in 5 ns, this enables fixation of the moment of pulse input from the detector with an accuracy to + or - 2.5 ns. Along with the fast memory, a slow memory with the cell switching in 1 micron s is introduced in the system, this permits observation of relatively large time intervals with respect to the trigger pulse with an appropriately lower accuracy

    Weak and Magnetic Inelastic Scattering of Antineutrinos on Atomic Electrons

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    Neutrino scattering on electrons is considered as a tool for laboratory searches of the neutrino magnetic moment. We study inelastic νˉee−\bar\nu_ee^--scattering on electrons bound in the germanium (Z=32) and iodine (Z=53) atoms for antineutrinos generated in a nuclear reactor core and also in the 90^{90}Sr-90^{90}Y and 147^{147}Pm artificial sources. Using the relativistic Hartree-Fock-Dirac model, we calculate both the magnetic and weak scattering cross sections for the recoil electron energy range of 1 to 100 keV where a higher sensitivity to the neutrino magnetic moment could be achieved. Particular attention is paid to the approximate procedure which allows us to take into account the effects of atomic binding on the inelastic scattering spectra in a simple way.Comment: 7 pages in LaTeX, 10 figures in P

    Reactor monitoring and safeguards using antineutrino detectors

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    Nuclear reactors have served as the antineutrino source for many fundamental physics experiments. The techniques developed by these experiments make it possible to use these very weakly interacting particles for a practical purpose. The large flux of antineutrinos that leaves a reactor carries information about two quantities of interest for safeguards: the reactor power and fissile inventory. Measurements made with antineutrino detectors could therefore offer an alternative means for verifying the power history and fissile inventory of a reactors, as part of International Atomic Energy Agency (IAEA) and other reactor safeguards regimes. Several efforts to develop this monitoring technique are underway across the globe.Comment: 6 pages, 4 figures, Proceedings of XXIII International Conference on Neutrino Physics and Astrophysics (Neutrino 2008); v2: minor additions to reference

    Disruption of Particle Detector Electronics by Beam Generated EMI

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    The possibility that radio frequency beam generated electromagnetic interference (EMI) could disrupt the operation of particle detector electronics has been of some concern since the inception of short pulse electron colliders more than 30 years ago [1]. Some instances have been reported where this may have occurred but convincing evidence has not been available. This possibility is of concern for the International Linear Collider (ILC). We have conducted test beam studies demonstrating that electronics disruption does occur using the vertex detector electronics (VXD) from the SLD detector which took data at the SLC at SLAC. We present the results of those tests, and we describe the need for EMI standards for beam and detector instrumentation in the IR region at the ILC

    Neutrino oscillations and uncertainty relations

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    We show that coherent flavor neutrino states are produced (and detected) due to the momentum-coordinate Heisenberg uncertainty relation. The Mandelstam-Tamm time-energy uncertainty relation requires non-stationary neutrino states for oscillations to happen and determines the time interval (propagation length) which is necessary for that. We compare different approaches to neutrino oscillations which are based on different physical assumptions but lead to the same expression for the neutrino transition probability in standard neutrino oscillation experiments. We show that a Moessbauer neutrino experiment could allow to distinguish different approaches and we present arguments in favor of the 163Ho-163Dy system for such an experiment.Comment: Some small changes in section 2, results unchanged. Added referenc

    Air ions induced aerosol sensing by eye-safe LIDAR

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    Low concentrations aerosols quantification is rather challenging for LIDAR instruments due to eye-safety restrictions so high energy pulses cannot be utilized to improve the sensitivity. Highly sensitive but eye-save LIDAR has been developed for the quantification of the water droplet aerosol which was induced by air ions. Few days sensing of aerosols in closed tunnel revealed a strong correlation between air optical transparency (LIDAR measurements) and concentrations of positive/negative ions (ion counter Sapphir 3-M). The correlation coefficient was observed to be almost unity for the air transparency signal and air ions unipolarity coefficient. High sensitivity of the water droplet aerosol quantification makes the developed eye-safe LIDAR a perspective instrument for space resolved measurements of the air ions distribution. Space and time resolved measurements of air ions exhalation can be a new instrument for tectonic activity study including new earthquake forecasting indicators search

    Observation of exotic meson production in the reaction π−p→η′π−p \pi^{-} p \to \eta^{\prime} \pi^- p at 18 GeV/c

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    An amplitude analysis of an exclusive sample of 5765 events from the reaction π−p→η′π−p\pi^{-} p \to \eta^{\prime} \pi^- p at 18 GeV/c is described. The η′π−\eta^{\prime} \pi^- production is dominated by natural parity exchange and by three partial waves: those with JPC=1−+,2++,J^{PC} = 1^{-+}, 2^{++}, and 4++4^{++}. A mass-dependent analysis of the partial-wave amplitudes indicates the production of the a2(1320)a_2(1320) meson as well as the a4(2040)a_4(2040) meson, observed for the first time decaying to η′π−\eta^{\prime}\pi^-. The dominant, exotic (non-qqˉ)q\bar{q}) 1−+1^{-+} partial wave is shown to be resonant with a mass of 1.597±0.010−0.010+0.0451.597 \pm 0.010^{+0.045}_{-0.010} GeV/c^2 and a width of 0.340±0.040±0.0500.340 \pm 0.040 \pm 0.050 GeV/c^2 . This exotic state, the π1(1600)\pi_1(1600), is produced with a tt dependence which is different from that of the a2(1320)a_2(1320) meson, indicating differences between the production mechanisms for the two states.Comment: 5 pages with 4 figure
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