251. Energy response of ISS-CREAM calorimeter with attenuation effectH.G. Zhang, Jon Paul Lundquist, 2020, drugi sestavni deli Opis: 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.
Ključne besede: cosmic rays, high-energy, particle physics, detectors
Objavljeno v RUNG: 29.04.2020; Ogledov: 3126; Prenosov: 166
 Celotno besedilo (2,54 MB) |
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253. A systematic uncertainty on the energy scale of the Telescope Array fluorescence detectorsT. Fujii, Jon Paul Lundquist, 2018, objavljeni znanstveni prispevek na konferenci Opis: The Telescope Array experiment (TA) is the largest cosmic-ray detector in the northern hemi-sphere and consists of a surface detector (SD) array, plus three fluorescence detector (FD) stations overlooking the SD. The large field-of-view of an FD allows for reconstruction of the air-shower development in the atmosphere by imaging ultra-violet fluorescence light from atmospheric nitrogen excited by UHECRs. In estimation of the primary energy it is necessary to add to the calorimetric energy observed by the FD a “missing energy”, meaning the fraction of the primary energy that is not deposited by charged particles in the air. We report on the measurement of the missing energy from observed data collected by the TA FD and TA SD, independently of Monte Carlo simulations, using a technique pioneered by the Pierre Auger Observatory. We also address the effect on the energy scale attributed to fluorescence yield parameters.
Ključne besede: UHECR, cosmic rays, energy spectrum
Objavljeno v RUNG: 29.04.2020; Ogledov: 2643; Prenosov: 80
Celotno besedilo (4,74 MB) |
254. Evidence of Intermediate-Scale Energy Spectrum Anisotropy of Cosmic Rays E>10^19.2 eV with the Telescope Array Surface DetectorJon Paul Lundquist, objavljeni povzetek znanstvenega prispevka na konferenci Opis: Evidence of an intermediate-scale energy spectrum anisotropy has been found in the arrival directions of ultra-high energy cosmic rays of energies above 10^19.2 eV in the northern hemisphere, using 7 years of Telescope Array (TA) surface detector (SD) data. A relative energy distribution test is done comparing events inside oversampled spherical caps of equal exposure, to those outside, using the Poisson likelihood ratio. The center of maximum significance is at 139 R.A., 45 Dec., and has a deficit of events with energies 10^19.210^19.75 eV. The post-trial probability of this energy anisotropy, appearing by chance anywhere on an isotropic sky, is found by Monte Carlo
(MC) simulation to be 9x10^-5 (3.74 σ_global).
Ključne besede: UHECR, cosmic rays, energy spectrum, anisotropy
Objavljeno v RUNG: 29.04.2020; Ogledov: 2646; Prenosov: 82
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255. Evidence of Intermediate-Scale Energy Spectrum Anisotropy in the Northern Hemisphere from Telescope ArrayJon Paul Lundquist, 2018, objavljeni znanstveni prispevek na konferenci Opis: Evidence of an energy dependent intermediate-scale anisotropy has been found in the arrival directions of ultra-high energy cosmic rays in the northern hemisphere, using 7 years of TA surface detector data. The previously reported ``hot spot" excess E ≥ 10^19.75 EeV is found to correspond to a deficit, or ``cold spot," of events for 10^19.2≤ E < 10^19.75 EeV. This feature suggests energy dependent magnetic deflection of cosmic-rays. The global post-trial significance of the energy spectrum deviation is found to be 3.74σ.
Ključne besede: UHECR, cosmic rays, energy spectrum, anisotropy, magnetic deflection
Objavljeno v RUNG: 28.04.2020; Ogledov: 2765; Prenosov: 79
Celotno besedilo (4,87 MB) |
256. Telescope Array Hot/Coldspot Study – Intermediate Scale AnisotropyJon Paul Lundquist, objavljeni povzetek znanstvenega prispevka na konferenci Opis: Indications of energy dependent intermediate scale anisotropy has been found in the arrival directions of ultra high energy cosmic rays with energies above 20 EeV in the northern hemisphere, using 7 years of TA surface detector data. The previously reported “hotspot‘” excess for E>57 EeV is found to correspond to a deficit, or “coldspot ”, of events for energies 2057 EeV has a Li Ma statistical significance of 4.62σ, and the deficit for energies 20Ključne besede: cosmic rays, energy spectrum, anisotropy, magnetic deflection
Objavljeno v RUNG: 28.04.2020; Ogledov: 2765; Prenosov: 0
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257. Track Reconstruction for ISS-CREAM Resulting in Improved Energy and Charge ResolutionsJon Paul Lundquist, 2019, objavljeni znanstveni prispevek na konferenci Opis: 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.
Ključne besede: cosmic rays, high energy, detectors, track fitting
Objavljeno v RUNG: 28.04.2020; Ogledov: 2702; Prenosov: 84
Celotno besedilo (481,98 KB) |
258. Supergalactic Structure of Multiplets with the Telescope Array Surface DetectorJon Paul Lundquist, P. Sokolsky, 2019, objavljeni znanstveni prispevek na konferenci Opis: Evidence of supergalactic structure of multiplets has been found for ultra-high energy cosmic rays (UHECR) with energies above 10^19 eV using 7 years of data from the Telescope Array (TA) surface detector. The tested hypothesis is that UHECR sources, and intervening magnetic fields, may be correlated with the supergalactic plane, as it is a fit to the average matter density within the GZK horizon. This structure is measured by the average behavior of the strength of intermediate-scale correlations between event energy and position (multiplets). These multiplets are measured in wedge-like shapes on the spherical surface of the fieldof-view to account for uniform and random magnetic fields. The evident structure found is consistent with toy-model simulations of a supergalactic magnetic sheet and the previously published Hot/Coldspot results of TA. The post-trial probability of this feature appearing by chance, on an isotropic sky, is found by Monte Carlo simulation to be ~4.5σ.
Ključne besede: UHECR, cosmic rays, energy spectrum, anisotropy, large-scale structure, magnetic deflection
Objavljeno v RUNG: 28.04.2020; Ogledov: 2834; Prenosov: 150
Celotno besedilo (1,38 MB) |
259. Improving Particle Identification with Resistant Track Finding for the ISS-CREAM CalorimeterJon Paul Lundquist, objavljeni povzetek znanstvenega prispevka na konferenci Opis: 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.
Ključne besede: cosmic rays, high energy, track finding
Objavljeno v RUNG: 28.04.2020; Ogledov: 2931; Prenosov: 0
Gradivo ima več datotek! Več... |
260. Supergalactic Structure of Energy-Angle CorrelationsJon Paul Lundquist, P. Sokolsky, 2020, objavljeni znanstveni prispevek na konferenci Opis: Evidence for the supergalactic structure of multiplets (energy-angle correlations) has previously been shown using ultra-high energy cosmic ray (UHECR) data from Telescope Array (TA) with energies above 10^19 eV. The supergalactic deflection hypothesis (that UHECR sources and intervening magnetic fields are correlated) is measured by the all-sky behavior of the strength of
intermediate-scale correlations. The multiplets are measured in spherical surface wedge bins of the field-of-view to account for uniform and random magnetic fields. The structure found is consistent with the previously published energy spectrum anisotropy results of TA and toy-model simulations of a supergalactic magnetic sheet. The 7 year data post-trial significance of this feature appearing by chance, on an isotropic sky, was found by Monte Carlo simulation to be ∼4σ. The analysis has now been applied to 10 years of data.
Ključne besede: Cosmic rays, UHECR, energy spectrum, magnetic deflection, large-scale structure, supergalactic, multiplets
Objavljeno v RUNG: 27.04.2020; Ogledov: 2717; Prenosov: 85
Celotno besedilo (1,66 MB) |
