1,883 research outputs found

    Science Objectives of the JEM EUSO Mission on International Space Station

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    JEM-EUSO space observatory is planned with a very large exposure factor which will exceed the critical exposure factor required for observing the most of the sources within the propagational horizon of about one hundred Mpc. The main science objective of JEM-EUSO is the source-identifying astronomy in particle channel with extremey-high-energy particles. Quasi-linear tracking of the source objects through galactic magnetic field should become feasible at energy > 10(exp 20) eV for all-sky. The individual GZK profile in high statistics experiments should differ from source to source due to different distance unless Lorentz invariance is somehow limited. hi addition, JEM-EUSO has three exploratory test observations: (i), extremely high energy neutrinos beginning at E > 10(exp 19) eV: neutrinos as being expected to have a slowly increasing cross section in the Standard Model, and in particular, hundreds of times more in the extra-dimension models. (ii). fundamental physics at extreme Super LHC (Large Hadronic Collider) energies with the hierarchical unified energy much below the GUT scale, and (iii). global atmospheric observation, including large-scale and local plasma discharges, night-glow, meteorites, and others.

    Cosmic Ray-Air Shower Measurement from Space

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    A feasibility study has been initiated to observe from space the highest energy cosmic rays above 1021 eV. A satellite observatory concept, the Maximum-energy Auger (Air)-Shower Satellite (MASS), is recently renamed as the Orbital Wide-angle Collector (OWL) by taking its unique feature of using a very wide field-of-view (FOV) optics. A huge array of imaging devices (about 10(exp 6) pixels) is required to detect and record fluorescent light profiles of cosmic ray cascades in the atmosphere. The FOV of MASS could extend to as large as about 60 in. diameter, which views (500 - 1000 km) of earth's surface and more than 300 - 1000 cosmic ray events per year could be observed above 1020 eV. From far above the atmosphere, the MASS/OWL satellite should be capable of observing events at all angles including near horizontal tracks, and would have considerable aperture for high energy photon and neutrino observation. With a large aperture and the spatial and temporal resolution, MASS could determine the energy spectrum, the mass composition, and arrival anisotropy of cosmic rays from 1020 eV to 1022 eV; a region hitherto not explored by ground-based detectors such as the Fly's Eye and air-shower arrays. MASS/OWL's ability to identify cosmic neutrinos and gamma rays may help providing evidence for the theory which attributes the above cut-off cosmic ray flux to the decay of topological defects. Very wide FOV optics system of MASS/OWL with a large array of imaging devices is applicable to observe other atmospheric phenomena including upper atmospheric lightning. The wide FOV MASS optics being developed can also improve ground-based gamma-ray observatories by allowing simultaneous observation of many gamma ray sources located at different constellations

    Iron Losses of Silicon Steel due to Rotating Fluxes (Inclined Rotating Flux and Distorted One)

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    Characteristics of iron losses in silicon steel due to inclined rotating fluxes and distorted ones are described. Iron losses due to rotating fluxes have been measured at various conditions for grain-oriented and non-oriented silicon steels by using an improved thermistor-bridge method. Loss measurements indicate that the iron loss due to the inclined rotating flux is greater than that due to the non-inclined one. However, the iron loss due to the distorted rotating flux is not always greater than that due to the non-distorted one

    Identifying Subclasses of Long Gamma-Ray Bursts with Cumulative Light Curve Morphology of Prompt Emissions

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    We argue a new classification scheme of long gamma-ray bursts (LGRBs) using the morphology of the cumulative light curve of the prompt emission. We parametrize the morphology by the absolute deviation from their constant luminosity (ADCLADCL) and derive the value for 36 LGRBs which have spectropic redshifts, spectral parameters determined by the Band model, 1-second peak fluxes, fluences, and 64-msec resolution light curves whose peak counts are 10 times larger than background fluctuations. Then we devide the sample according to the value of ADCL into two groups (ADCL0.17ADCL 0.17) and, for each group, derive the spectral peak energy EpE_{\rm p} - peak luminosity LpL_{\rm p} correlation and the Fundamental Plane of LGRBs, which is a correlation between the spectral peak energy EpE_{\rm p}, the luminosity time TLT_{\rm L} (Eiso/Lp\equiv E_{\rm iso}/L_{\rm p} where EisoE_{\rm iso} is isotropic energy) and the peak luminosity LpL_{\rm p}. We find that both of the correlations for both groups are statistically more significant compared with ones derived from all samples. The Fundamental Planes with small and large ADCL are given by Lp=1052.53±0.01(Ep/102.71keV)1.84±0.03(TL/100.86sec)0.29±0.08L_{\rm p}=10^{52.53\pm 0.01}(E_{\rm p}/10^{2.71}{\rm keV})^{1.84\pm 0.03} (T_{\rm L}/10^{0.86}{\rm sec})^{0.29\pm0.08} with χν2=10.93/14\chi^2_{\nu}=10.93/14 and Lp=1052.98±0.08(Ep/102.71keV)1.82±0.09(TL/100.86sec)0.85±0.27L_{\rm p}=10^{52.98\pm0.08}(E_{\rm p}/10^{2.71}{\rm keV})^{1.82\pm 0.09} (T_{\rm L}/10^{0.86}{\rm sec})^{0.85\pm 0.27} with χν2=7.58/8\chi^2_{\nu}=7.58/8, respectively. This fact implies the existence of subclasses of LGRBs characterized by the value of ADCLADCL. Also there is a hint for the existence of the intermediate-ADCLADCL class which deviates from both fundamental planes. Both relations are so tight that our result provides a new accurate distance measurement scheme up to the high redshift universe.Comment: 10 pages, 8 figures, 2 tables. Submitted to PAS

    Effect of eddy current in shielding plate and electron gun on flux distribution in CRT

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    The eddy current induced in an inner magnetic shield (IMS) and an electron gun affect the flux distribution of a cathode ray tube, causing a possible degrade of picture quality. In this paper, the effect of the distance between an IMS and a deflection coil on the eddy-current distribution is examined. The eddy current induced in the electron gun, when the coils for velocity modulation (VM) are set near the electron gun, is also analyzed. It is found that the variation of flux distribution is mainly affected by the shape of VM coil.</p
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