In this paper we infer the mass composition of the ultra high energy cosmic rays (UHECRs) from measurements of Xmax distributions recorded at the Pierre Auger (2014) and Telescope Array (TA) (2016) ...Observatories, by fitting them with all possible combinations of Monte Carlo (MC) templates from a large set of primary species (p, He, C, N, O, Ne, Si and Fe), as predicted by EPOS-LHC, QGSJETII-04 and Sibyll 2.1 hadronic interaction models. We use the individual fractions of nuclei reconstructed from one experiment in each energy interval to build equivalent MC Xmax distributions, which we compare with the experimental Xmax distributions of the other experiment, applying different statistical tests of compatibility. The results obtained from both experiments confirm that the mass composition of the UHECRs is dominated (≳70%) by protons and He nuclei in the energy range investigated lgE(eV) = 17.8–19.3 (Auger) and lgE(eV) = 18.2–19.0 (TA). The indirect comparisons between the Xmax distributions recorded by the two experiments show that the degree of compatibility of the two datasets is good, even excellent in some high energy intervals, especially above the ankle (lgE(eV)∼18.7). However, our study reveals that, at low energies, further effort in data analysis is required in order to harmonize the results of the two experiments.
The limited knowledge of atmospheric parameters like humidity, pressure, temperature, and the index of refraction has been one of the important systematic uncertainties in reconstructing the depth of ...the shower maximum from the radio emission of air showers. Current air shower Monte Carlo simulation codes like CORSIKA and the radio plug-in CoREAS use various averaged parameterized atmospheres. However, time-dependent and location-specific atmospheric models are needed for the cosmic ray analysis method used for LOFAR data. There, dedicated simulation sets are used for each detected cosmic ray, to take into account the actual atmospheric conditions at the time of the measurement. Using the Global Data Assimilation System (GDAS), a global atmospheric model, we have implemented time-dependent, realistic atmospheric profiles in CORSIKA and CoREAS. We have produced realistic event-specific atmospheres for all air showers measured with LOFAR, an event set spanning several years and many different weather conditions. A complete re-analysis of our data set shows that for the majority of data, our previous correction factor performed rather well; we found only a small systematic shift of 2 g/cm2 in the reconstructed Xmax. However, under extreme weather conditions, for example, very low air pressure, the shift can be up to 15 g/cm2. We provide a correction formula to determine the shift in Xmax resulting from a comparison of simulations done using the US-Std atmosphere and the GDAS-based atmosphere.
A new modulation and demodulation scheme Jin Qi
2010 International Conference on Future Information Technology and Management Engineering,
2010-Oct., Volume:
1
Conference Proceeding
Recently, because of the increase in spectrum demand, sine-like modulation has been proposed. In this new scheme, the side band of power spectrum density is rather low, so that it wouldn't cause ...interference to other signals. In this paper, we proposed a new kind of sine-like modulation, and also analyzed the corresponding demodulation scheme in detail.
Provider: - Institution: - Data provided by Europeana Collections- Karlsruhe, Karlsruher Institut für Technologie (KIT), Diss., 2014- All metadata published by Europeana are available free of ...restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- Karlsruhe, Karlsruher Institut für Technologie (KIT), Diss., 2012- All metadata published by Europeana are available free of ...restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
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