The Cosmic-Ray Composition between 2 PeV and 2 EeV Observed with the TALE Detector in Monocular Mode

Abstract

We report on a measurement of the cosmic ray composition by the Telescope Array Low-Energy Extension (TALE) air fluorescence detector (FD). By making use of the Cherenkov light signal in addition to air fluorescence light from cosmic ray (CR) induced extensive air showers, the TALE FD can measure the properties of the cosmic rays with energies as low as $\sim 2$ PeV and exceeding 1 EeV. In this paper, we present results on the measurement of $X_{\max }$ distributions of showers observed over this energy range. Data collected over a period of $\sim 4$ years was analyzed for this study. The resulting $X_{\max }$ distributions are compared to the Monte Carlo (MC) simulated data distributions for primary cosmic rays with varying composition and a 4-component fit is performed. The comparison and fit are performed for energy bins, of width 0.1 or 0.2 in ${\log }_{10}(E/\mathrm{eV})$, spanning the full range of the measured energies. We also examine the mean $X_{\max }$ value as a function of energy for cosmic rays with energies greater than $10^{15.8}$ eV. Below $10^{17.3}$ eV, the slope of the mean $X_{\max }$ as a function of energy (the elongation rate) for the data is significantly smaller than that of all elements in the models, indicating that the composition is becoming heavier with energy in this energy range. This is consistent with a rigidity-dependent cutoff of events from galactic sources. Finally, an increase in the $X_{\max }$ elongation rate is observed at energies just above $10^{17}$ eV indicating another change in the cosmic rays composition.

20 pages, 22 figures, accepted for publication in ApJ

References in corpus (21)

• EPOS LHC : test of collective hadronization with LHC data
• Monte Carlo treatment of hadronic interactions in enhanced Pomeron scheme: I. QGSJET-II model
• The IceCube Neutrino Observatory: Instrumentation and Online Systems
• KASCADE measurements of energy spectra for elemental groups of cosmic rays: Results and open problems
• The surface detector array of the Telescope Array experiment
• Indications of Intermediate-Scale Anisotropy of Cosmic Rays with Energy Greater Than 57 EeV in the Northern Sky Measured with the Surface Detector of the Telescope Array Experiment
• Spectrum of cosmic-ray nucleons and the atmospheric muon charge ratio
• One-dimensional Hybrid Approach to Extensive Air Shower Simulation
• Proton and Helium Spectra from the CREAM-III Flight
• New air fluorescence detectors employed in the Telescope Array experiment
• The Cosmic Ray Energy Spectrum Observed with the Surface Detector of the Telescope Array Experiment
• Simulation of Imaging Atmospheric Cherenkov Telescopes with CORSIKA and sim_telarray
• IceTop: The surface component of IceCube
• Study of Ultra-High Energy Cosmic Ray Composition Using Telescope Array's Middle Drum Detector and Surface Array in Hybrid Mode
• A Study of the Composition of Ultra High Energy Cosmic Rays Using the High Resolution Fly's Eye
• Cosmic Ray Spectrum and Composition from PeV to EeV Using 3 Years of Data From IceTop and IceCube
• Ultra high energy cosmic rays: implications of Auger data for source spectra and chemical composition
• Depth of Ultra High Energy Cosmic Ray Induced Air Shower Maxima Measured by the Telescope Array Black Rock and Long Ridge FADC Fluorescence Detectors and Surface Array in Hybrid Mode
• The Cosmic-Ray Energy Spectrum between 2 PeV and 2 EeV Observed with the TALE detector in monocular mode
• Final Results from the High Resolution Fly's Eye (HiRes) Experiment
• The Energy Spectrum of Telescope Array's Middle Drum Detector and the Direct Comparison to the High Resolution Fly's Eye Experiment

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• Ultra-High-Energy Cosmic Rays: The Intersection of the Cosmic and Energy Frontiers
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• Galactic contribution to the high-energy neutrino flux found in track-like IceCube events
• Magnetically Arrested Disks in Quiescent Black-Hole Binaries: Formation Scenario, Observable Signatures, and Potential PeVatrons
• Framework and Tools for the Simulation and Analysis of the Radio Emission from Air Showers at IceCube
• Energy spectra of elemental groups of cosmic rays with the KASCADE experiment data and machine learning
• Determination of the Cosmic-Ray Chemical Composition: Open Issues and Prospects
• The Unreasonable Effectiveness of the Air-Fluorescence Technique in Determining the EAS Shower Maximum
• A LOFAR-style reconstruction of cosmic-ray air showers with SKA-Low
• Methods of machine learning for the analysis of cosmic rays mass composition with the KASCADE experiment data
• In-ice Askaryan Emission from Air Showers: Implications for Radio Neutrino Detectors
• Precise Measurement of the Cosmic Ray Helium Spectrum above 0.1 PeV
• Very-high-energy gamma rays from cosmic rays escaping from Galactic black hole binaries
• Measuring temporal characteristics of the Cherenkov radiation signal from extensive air showers of cosmic rays with a wide field-of-view telescope addendum to the Yakutsk array
• Cosmic ray mass composition measurement in the energy range from $10^{16.5}$ eV to $10^{18.5}$ eV observed with the TALE hybrid detector
• The Sensitivity of PUEO to Cosmogenic Neutrinos and Exotic Physics Scenarios