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71.
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)

72.
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)

73.
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
Summary of found: ...The Telescope Array experiment studies ultra high energy cosmic rays using a hybrid detector....
Keywords: Cosmic rays, Energy spectrum, Telescope Array, Hybrid, Ultra high energy
Published: 27.04.2020; Views: 1458; Downloads: 0
.pdf Fulltext (3,12 MB)

74.
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 ultra high-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)

75.
Improving Particle Identification with Resistant Track Finding for the ISS-CREAM Calorimeter
J. P. Lundquist, published scientific conference contribution abstract

Abstract: Moving from Antarctic balloons to the International Space Station the Cosmic Ray Energetics And Mass detector (ISS-CREAM) has begun taking the highest energy direct measurements of cosmic ray (CR) particles ever attempted. ISS-CREAM will investigate how the energy distributions evolve, for protons all the way to iron nuclei, and will provide important information for models of galactic sources and CR propagation. The CR particle identification can be significantly improved by tracking particle-detector interactions from the calorimeter (for energy measurement) back to the Silicon Charge Detector for atomic number determination. A track finding algorithm resistant to such issues as particle multiplicity, backscatter, and noise is outlined.
Found in: ključnih besedah
Summary of found: ...cosmic rays, high energy, track finding...
Keywords: cosmic rays, high energy, track finding
Published: 28.04.2020; Views: 1495; Downloads: 0
.pdf Fulltext (3,23 MB)

76.
Track Reconstruction for ISS-CREAM Resulting in Improved Energy and Charge Resolutions
J. P. Lundquist, 2019, published scientific conference contribution

Abstract: Cosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM) has taken 1.5 years of direct measurements of high-energy cosmic ray (HECR) particles for energies from 10^12 to 10^15 eV. HECR particle identification is significantly improved by tracking particle-detector interactions from the calorimeter (CAL) back to the Silicon Charge Detector (SCD) for charge determination. A track finding algorithm resistant to such issues as particle multiplicity, backscatter, and electronic noise will be outlined. Also, shown is the energy resolution improvement, and the resulting all particle spectrum, provided by ensuring good particle tracks. This allows ISSCREAM to investigate how the energy distributions evolve, for protons all the way to iron nuclei, and will provide important information for models of galactic sources and HECR propagation.
Found in: ključnih besedah
Summary of found: ...taken 1.5 years of direct measurements of high-energy cosmic ray (HECR) particles for energies from...
Keywords: cosmic rays, high energy, detectors, track fitting
Published: 28.04.2020; Views: 1497; Downloads: 52
.pdf Fulltext (481,98 KB)

77.
Energy response of ISS-CREAM calorimeter with attenuation effect
J. P. Lundquist, H.G. Zhang, 2020, other component parts

Abstract: The NASA mission, Cosmic Ray Energetic And Mass experiment for the International Space Station (ISS-CREAM) is to measure individual cosmic-ray particle energy spectra from protons to iron nuclei, with an energy range from ~1 TeV to the so-called "knee", near 1015eV. Energies of cosmic-ray particles are measured from electromagnetic showers induced by particles in the calorimeter. As a pioneer mission, the balloon-borne CREAM instrument has successfully flown seven times over the Antarctica for a cumulative exposure of 191 days. The CREAM calorimeter has shown sufficient capability to measure energies of cosmic-ray particles by capturing the electromagnetic shower profile within the interested energy range. The ISS-CREAM calorimeter is expected to have a similar performance and, before it was launched, an engineering-unit calorimeter was shipped to CERN for a full beam test. The full performance test includes position, energy, and angle scans of electron and pion beams together with a high voltage scan for calibration and characterization. In addition to the regular analysis for performance test, we also applied an additional step to generate the universal energy responses by correcting the attenuation effect in the calorimeter readout. The general energy responses could be obtained after shifting the incident beam positions to a reference position near the center of the calorimeter, which provided improved energy resolutions. The result of this analysis will be used to determine the incident energies of the cosmic-ray particles in the flight data.
Found in: ključnih besedah
Summary of found: ...electron and pion beams together with a high voltage scan for calibration and characterization. In addition...
Keywords: cosmic rays, high-energy, particle physics, detectors
Published: 29.04.2020; Views: 1511; Downloads: 70
.pdf Fulltext (2,54 MB)

78.
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)

79.
The bursts of high energy events observed by the telescope array surface detector
J. P. Lundquist, R.U. Abbasi, 2017, original scientific article

Abstract: The Telescope Array (TA) experiment is designed to detect air showers induced by ultra high energy cosmic rays. The TA ground Surface particle Detector (TASD) observed several short-time bursts of air shower like events. These bursts are not likely due to chance coincidence between single shower events. The expectation of chance coincidence is less than 10^-4 for five-year's observation. We checked the correlation between these bursts of events and lightning data, and found evidence for correlations in timing and position. Some features of the burst events are similar to those of a normal cosmic ray air shower, and some are not. On this paper, we report the observed bursts of air shower like events and their correlation with lightning.
Found in: ključnih besedah
Keywords: High energy radiation, Lightning, Terrestrial gamma-ray flash
Published: 30.04.2020; Views: 1474; Downloads: 0
.pdf Fulltext (1,70 MB)

80.
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)

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