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41.
Study of Ultra-High Energy Cosmic Ray composition using Telescope Array’s Middle Drum detector and surface array in hybrid mode
Jon Paul Lundquist, R.U. Abbasi, 2015, original scientific article

Abstract: Previous measurements of the composition of Ultra-High Energy Cosmic Rays (UHECRs) made by the High Resolution Fly’s Eye (HiRes) and Pierre Auger Observatory (PAO) are seemingly contradictory, but utilize different detection methods, as HiRes was a stereo detector and PAO is a hybrid detector. The five year Telescope Array (TA) Middle Drum hybrid composition measurement is similar in some, but not all, respects in methodology to PAO, and good agreement is evident between data and a light, largely protonic, composition when comparing the measurements to predictions obtained with the QGSJetII-03 and QGSJet-01c models. These models are also in agreement with previous HiRes stereo measurements, confirming the equivalence of the stereo and hybrid methods. The data is incompatible with a pure iron composition, for all models examined, over the available range of energies. The elongation rate and mean values of are in good agreement with Pierre Auger Observatory data. This analysis is presented using two methods: data cuts using simple geometrical variables and a new pattern recognition technique.
Found in: ključnih besedah
Keywords: Ultra-High Energy Cosmic Rays, Cosmic ray composition, Atmospheric fluorescence, Extensive air shower array, Hybrid, Telescope Array
Published: 24.04.2020; Views: 1669; Downloads: 0
.pdf Fulltext (3,45 MB)

42.
The energy spectrum of cosmic rays above 1017.2 eV measured by the fluorescence detectors of the Telescope Array experiment in seven years
J. P. Lundquist, R.U. Abbasi, 2016, original scientific article

Abstract: The Telescope Array (TA) experiment is the largest detector to observe ultra-high-energy cosmic rays in the northern hemisphere. The fluorescence detectors at two stations of TA are newly constructed and have now completed seven years of steady operation. One advantage of monocular analysis of the fluorescence detectors is a lower energy threshold for cosmic rays than that of other techniques like stereoscopic observations or coincidences with the surface detector array, allowing the measurement of an energy spectrum covering three orders of magnitude in energy. Analyzing data collected during those seven years, we report the energy spectrum of cosmic rays covering a broad range of energies above 10^17.2eV measured by the fluorescence detectors and a comparison with previously published results.
Found in: ključnih besedah
Summary of found: ...experiment is the largest detector to observe ultra-high-energy cosmic rays in the northern hemisphere. The...
Keywords: Cosmic rays, Ultra-high energy, Fluorescence detector, Energy spectrum, Ankle, GZK cutoff
Published: 27.04.2020; Views: 1526; Downloads: 0
.pdf Fulltext (1,23 MB)

43.
Measurement of the proton-air cross section with Telescope Array’s Middle Drum detector and surface array in hybrid mode
J. P. Lundquist, R.U. Abbasi, 2015, original scientific article

Found in: ključnih besedah
Summary of found: ...Cosmic Rays, proton cross-section, ultra-high energy, particle physics...
Keywords: Cosmic Rays, proton cross-section, ultra-high energy, particle physics
Published: 27.04.2020; Views: 1496; Downloads: 0
.pdf Fulltext (409,81 KB)

44.
The hybrid energy spectrum of Telescope Array’s Middle Drum Detector and surface array
J. P. Lundquist, R.U. Abbasi, 2015, original scientific article

Abstract: The Telescope Array experiment studies ultra high energy cosmic rays using a hybrid detector. Fluorescence telescopes measure the longitudinal development of the extensive air shower generated when a primary cosmic ray particle interacts with the atmosphere. Meanwhile, scintillator detectors measure the lateral distribution of secondary shower particles that hit the ground. The Middle Drum (MD) fluorescence telescope station consists of 14 telescopes from the High Resolution Fly’s Eye (HiRes) experiment, providing a direct link back to the HiRes measurements. Using the scintillator detector data in conjunction with the telescope data improves the geometrical reconstruction of the showers significantly, and hence, provides a more accurate reconstruction of the energy of the primary particle. The Middle Drum hybrid spectrum is presented and compared to that measured by the Middle Drum station in monocular mode. Further, the hybrid data establishes a link between the Middle Drum data and the surface array. A comparison between the Middle Drum hybrid energy spectrum and scintillator Surface Detector (SD) spectrum is also shown.
Found in: ključnih besedah
Keywords: Cosmic rays, Energy spectrum, Telescope Array, Hybrid, Ultra high energy
Published: 27.04.2020; Views: 1458; Downloads: 0
.pdf Fulltext (3,12 MB)

45.
Indications of Proton-Dominated Cosmic-Ray Composition above 1.6 EeV
J. P. Lundquist, R.U. Abbasi, 2010, original scientific article

Abstract: We report studies of ultrahigh-energy cosmic-ray composition via analysis of depth of air shower maximum (Xmax), for air shower events collected by the High-Resolution Fly’s Eye (HiRes) observatory. The HiRes data are consistent with a constant elongation rate d⟨Xmax⟩/d[log(E)] of 47.9 ± 6.0 (stat) ± 3.2 (syst) g/cm^2/decade for energies between 1.6 and 63 EeV, and are consistent with a predominantly protonic composition of cosmic rays when interpreted via the QGSJET01 and QGSJET-II high-energy hadronic interaction models. These measurements constrain models in which the galactic-to-extragalactic transition is the cause of the energy spectrum ankle at 4×10^18 eV.
Found in: ključnih besedah
Summary of found: ...We report studies of ultrahigh- energy cosmic-ray composition via analysis of depth of...
Keywords: Cosmic rays, Energy spectrum, Telescope Array, Hybrid, Ultra high energy
Published: 27.04.2020; Views: 1487; Downloads: 0
.pdf Fulltext (314,89 KB)

46.
Constraints on the diffuse photon flux with energies above 10^18 eV using the surface detector of the Telescope Array experiment
J. P. Lundquist, R.U. Abbasi, 2018, original scientific article

Abstract: We present the results of the search for ultra-high-energy photons with nine years of data from the Telescope Array surface detector. A multivariate classifier is built upon 16 reconstructed parameters of the extensive air shower. These parameters are related to the curvature and the width of the shower front, the steepness of the lateral distribution function, and the timing parameters of the waveforms sensitive to the shower muon content. A total number of two photon candidates found in the search is fully compatible with the expected background. The 95% CL limits on the diffuse flux of the photons with energies greater than 10^18.0, 10^18.5, 10^19.0, 10^19.5 and 10^20.0 eV are set at the level of 0.067, 0.012, 0.0036, 0.0013, correspondingly.
Found in: ključnih besedah
Summary of found: ...present the results of the search for ultra-high-energy photons with nine years of data from...
Keywords: Ultra-high-energy photons, Telescope array experiment, Extensive air showers
Published: 30.04.2020; Views: 1571; Downloads: 0
.pdf Fulltext (1,33 MB)

47.
Energy spectrum of ultra-high energy cosmic rays observed with the Telescope Array using a hybrid technique
J. P. Lundquist, T. Abu-Zayyad, 2015, original scientific article

Abstract: We measure the spectrum of cosmic rays with energies greater than eV with the fluorescence detectors (FDs) and the surface detectors (SDs) of the Telescope Array Experiment using the data taken in our first 2.3-year observation from May 27, 2008 to September 7, 2010. A hybrid air shower reconstruction technique is employed to improve accuracies in determination of arrival directions and primary energies of cosmic rays using both FD and SD data. The energy spectrum presented here is in agreement with our previously published spectra and the HiRes results.
Found in: ključnih besedah
Keywords: Ultra-high energy cosmic rays, Telescope Array, Hybrid spectrum
Published: 30.04.2020; Views: 1586; Downloads: 0
.pdf Fulltext (267,06 KB)

48.
The surface detector array of the Telescope Array experiment
J. P. Lundquist, T. Abu-Zayyad, 2012, original scientific article

Abstract: The Telescope Array (TA) experiment, located in the western desert of Utah, USA, is designed for the observation of extensive air showers from extremely high energy cosmic rays. The experiment has a surface detector array surrounded by three fluorescence detectors to enable simultaneous detection of shower particles at ground level and fluorescence photons along the shower track. The TA surface detectors and fluorescence detectors started full hybrid observation in March, 2008. In this article we describe the design and technical features of the TA surface detector.
Found in: ključnih besedah
Summary of found: ...of extensive air showers from extremely high energy cosmic rays. The experiment has a surface...
Keywords: Ultra-high energy cosmic rays, Telescope Array experiment, Extensive air shower array
Published: 19.05.2020; Views: 1419; Downloads: 0
.pdf Fulltext (1,81 MB)

49.
New air fluorescence detectors employed in the Telescope Array experiment
J. P. Lundquist, H. Tokuno, 2012, original scientific article

Abstract: Since 2007, the Telescope Array (TA) experiment, based in Utah, USA, has been observing ultra high energy cosmic rays to understand their origins. The experiment includes a surface detector (SD) array and three fluorescence detector (FD) stations. The FD stations, installed surrounding the SD array, measure the air fluorescence light emitted from extensive air showers (EASs) for precise determination of their energies and species. The detectors employed at one of the three FD stations were relocated from the High Resolution Fly's Eye (HiRes) experiment. At the other two stations, newly designed detectors were constructed for the TA experiment. An FD consists of a primary mirror and a camera equipped with photomultiplier tube pixels. To obtain the EAS parameters with high accuracy, understanding the FD optical characteristics is important. In this paper, we report the characteristics and installation of the new FDs and the performances of the FD components. The results of the monitored mirror reflectance during the observation time are also described in this report.
Found in: ključnih besedah
Summary of found: ...Utah, USA, has been observing ultra high energy cosmic rays to understand their origins. The...
Keywords: Ultra high energy cosmic rays, Extensive air showers, Air fluorescence light detectors
Published: 19.05.2020; Views: 1295; Downloads: 0
.pdf Fulltext (1,44 MB)

50.
Highlights from the Pierre Auger Observatory
Lukas Zehrer, Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Marta Trini, Samo Stanič, Gašper Kukec Mezek, Andrej Filipčič, Antonella Castellina, 2019, published scientific conference contribution

Found in: ključnih besedah
Summary of found: ... ultra-high energy cosmic rays, extensive air showers, Pierre...
Keywords: ultra-high energy cosmic rays, extensive air showers, Pierre Auger Observatory
Published: 16.06.2020; Views: 1422; Downloads: 53
.pdf Fulltext (4,92 MB)

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