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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
Summary of found: ...of the composition of Ultra-High Energy Cosmic Rays (UHECRs) made by the High Resolution Fly’s...
Keywords: Ultra-High Energy Cosmic Rays, Cosmic ray composition, Atmospheric fluorescence, Extensive air shower array, Hybrid, Telescope Array
Published: 24.04.2020; Views: 1675; Downloads: 0
.pdf Fulltext (3,45 MB)

42.
Evidence for Declination Dependence of Ultrahigh Energy Cosmic Ray Spectrum in the Northern Hemisphere
J. P. Lundquist, R.U. Abbasi, 2018, other component parts

Abstract: The energy of the ultrahigh energy spectral cutoff was measured, integrating over the northern hemisphere sky, by the Telescope Array (TA) collaboration, to be 10^19.78±0.06 eV, in agreement with the High Resolution Fly's Eye (HiRes) experiment, whereas the Pierre Auger experiment, integrating over the southern hemisphere sky, measured the cutoff to be at 10^19.62±0.02 eV. An 11% energy scale difference between the TA and Auger does not account for this difference. However, in comparing the spectra of the Telescope Array and Pierre Auger experiments in the band of declination common to both experiments ( −15.7∘<δ<24.8∘ ) we have found agreement in the energy of the spectral cutoff. While the Auger result is essentially unchanged, the TA cutoff energy has changed to 10^19.59±0.06 eV. In this paper we argue that this is an astrophysical effect.
Found in: ključnih besedah
Summary of found: ...Astrophysics, High Energy Astrophysical Phenomena, UHECR, Cosmic Rays, Anisotropy, Energy Spectrum...
Keywords: Astrophysics, High Energy Astrophysical Phenomena, UHECR, Cosmic Rays, Anisotropy, Energy Spectrum
Published: 27.04.2020; Views: 1630; Downloads: 54
.pdf Fulltext (687,87 KB)

43.
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
Keywords: Cosmic rays, Ultra-high energy, Fluorescence detector, Energy spectrum, Ankle, GZK cutoff
Published: 27.04.2020; Views: 1532; Downloads: 0
.pdf Fulltext (1,23 MB)

44.
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: 1505; Downloads: 0
.pdf Fulltext (409,81 KB)

45.
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: ...Telescope Array experiment studies ultra high energy cosmic rays using a hybrid detector. Fluorescence telescopes...
Keywords: Cosmic rays, Energy spectrum, Telescope Array, Hybrid, Ultra high energy
Published: 27.04.2020; Views: 1470; Downloads: 0
.pdf Fulltext (3,12 MB)

46.
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... ...with a predominantly protonic composition of cosmic rays when interpreted via the QGSJET01 and QGSJET-II...
Keywords: Cosmic rays, Energy spectrum, Telescope Array, Hybrid, Ultra high energy
Published: 27.04.2020; Views: 1496; Downloads: 0
.pdf Fulltext (314,89 KB)

47.
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: ...balloons to the International Space Station the Cosmic Ray Energetics And Mass detector (ISS-CREAM) has... ...cosmic rays, high energy, track finding...
Keywords: cosmic rays, high energy, track finding
Published: 28.04.2020; Views: 1510; Downloads: 0
.pdf Fulltext (3,23 MB)

48.
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: ... Cosmic Ray Energetics And Mass for the International... ...cosmic rays, high energy, detectors, track fitting...
Keywords: cosmic rays, high energy, detectors, track fitting
Published: 28.04.2020; Views: 1506; Downloads: 52
.pdf Fulltext (481,98 KB)

49.
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: ...The NASA mission, Cosmic Ray Energetic And Mass experiment for the... ...cosmic rays, high-energy, particle physics, detectors...
Keywords: cosmic rays, high-energy, particle physics, detectors
Published: 29.04.2020; Views: 1522; Downloads: 70
.pdf Fulltext (2,54 MB)

50.
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: 1593; Downloads: 0
.pdf Fulltext (267,06 KB)

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