31. Effect of gamma irradiation on Schottky-contacted vertically aligned ZnO nanorod-based hydrogen sensorSapana Ranwa, Surendra Singh Barala, Mattia Fanetti, Mahesh Kumar, 2016, original scientific article Abstract: We report the impact of gamma irradiation on the performance of a gold Schottky-contacted ZnO nanorod-based hydrogen sensor. RF-sputtered vertically aligned highly c-axis-oriented ZnO NRs were grown on Si(100) substrate. X-ray diffraction shows no significant change in crystal structure at low gamma doses from 1 to 5 kGy. As gamma irradiation doses increase to 10 kGy, the single crystalline ZnO structure converts to polycrystalline. The photoluminescence spectra also shows suppression of the near-band emission peak and the huge wide-band spectrum indicates the generation of structural defects at high gamma doses. At 1 kGy, the hydrogen sensor response was enhanced from 67% to 77% for 1% hydrogen in pure argon at a 150 °C operating temperature. However, at 10 kGy, the relative response decreases to 33.5%. High gamma irradiation causes displacement damage and defects in ZnO NRs, and as a result, degrades the sensor's performance as a result. Low gamma irradiation doses activate the ZnO NR surface through ionization, which enhances the sensor performance. The relative response of the hydrogen sensor was enhanced by ∼14.9% with respect to pristine ZnO using 1 kGy gamma ray treatment. © 2016 IOP Publishing Ltd.
Found in: ključnih besedah
Keywords: ZnO, nanorods, gamma irradiation, sensor
Published: 12.01.2017; Views: 3343; Downloads: 0
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34. Prospects for Cherenkov Telescope Array Observations of the Young Supernova Remnant RX J1713.7−3946Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Samo Stanič, Gašper Kukec Mezek, F. Acero, 2017, original scientific article Found in: ključnih besedah
Summary of found: ...very-high energy gamma-rays,
supernova remnants (SNR), SNR RX J1713.7−3946,
Cherenkov Telescope Array...
Keywords: very-high energy gamma-rays, supernova remnants (SNR), SNR RX J1713.7−3946, Cherenkov Telescope Array
Published: 10.05.2017; Views: 3854; Downloads: 0
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35. Indirect Detection ExperimentsGabrijela Zaharijas, 2017, published scientific conference contribution abstract (invited lecture) Found in: ključnih besedah
Summary of found: ...to the latest indications of an unaccounted gamma-ray excess at few GeV in the Fermi-LAT...
Keywords: We live in a golden age for astro-particle physics, with a significant number of experiments actively monitoring high-energy Universe. Many of these probes provide excellent tests of particle physics models of dark matter particles. In particular, experiments such as Fermi -LAT, AMS-02, Ice Cube, ... are significantly cutting into the parameter space of one of the most popular candidates, the WIMPs. In this talk I will describe some of the strategies and methods used to search for dark matter with astrophysical data. Special attention will be given to the latest indications of an unaccounted gamma-ray excess at few GeV in the Fermi-LAT data in the region around the Galactic Centre, which steered lots of attention as it was shown to be consistent with putative signals of WIMP dark matter particles and complementary constraints provided by other experiments. Finally I will discuss projections of the expected sensitivities with upcoming experiments and continued data taking with current ones.
Published: 17.07.2017; Views: 3985; Downloads: 0
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37. New Frontiers in Black Hole Astrophysics2017, proceedings of peer-reviewed scientific conference contributions (international and foreign conferences) Found in: ključnih besedah
Summary of found: ...astronomy, black holes, active galactic nuclei, gamma ray bursts, tidal disruption events, gravitational waves...
Keywords: astronomy, black holes, active galactic nuclei, gamma ray bursts, tidal disruption events, gravitational waves
Published: 17.08.2017; Views: 3168; Downloads: 0
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40. Very high-energy gamma-ray signature of ultrahigh-energy cosmic-ray acceleration in Centaurus AJagdish Joshi, Marlui Miranda, Lili Yang, Soebur Razzaque, 2017, published scientific conference contribution abstract Abstract: The association of at least a dozen ultrahigh-energy cosmic-ray (UHECR) events with energy 54 EeV or higher detected by the Pierre Auger Observatory from the direction of Centaurus-A, the nearest radio galaxy, supports the scenario of UHECR acceleration in the jets of radio galaxies. Multiwavelength observations of Centaurus-A suggest that the inner jet is likely the site for particle acceleration, which emits in X-ray to very high-energy (VHE) gamma-ray. We model broadband spectral energy distribution with emission from shock-accelerated electrons and protons in a combined synchrotron-self-Compton and photo-hadronic scenario. The UHECR flux from Centaurus-A, required to explain Pierre Auger data, successfully explains observed VHE gamma rays as photo-hadronic emission.
Found in: ključnih besedah
Keywords: Centaurus A, gamma ray, cosmic rays
Published: 17.01.2018; Views: 2550; Downloads: 0
Fulltext (2,27 MB) |
