31. 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 ModeJ. P. Lundquist, R.U. Abbasi, 2018, izvirni znanstveni članek Opis: The Telescope Array (TA) observatory utilizes fluorescence detectors and surface detectors (SDs) to observe air showers produced by ultra high energy cosmic rays in Earth's atmosphere. Cosmic-ray events observed in this way are termed hybrid data. The depth of air shower maximum is related to the mass of the primary particle that generates the shower. This paper reports on shower maxima data collected over 8.5 yr using the Black Rock Mesa and Long Ridge fluorescence detectors in conjunction with the array of SDs. We compare the means and standard deviations of the observed Xmax distributions with Monte Carlo Xmax distributions of unmixed protons, helium, nitrogen, and iron, all generated using the QGSJet II-04 hadronic model. We also perform an unbinned maximum likelihood test of the observed data, which is subjected to variable systematic shifting of the data Xmax distributions to allow us to test the full distributions, and compare them to the Monte Carlo to see which elements are not compatible with the observed data. For all energy bins, QGSJet II-04 protons are found to be compatible with TA hybrid data at the 95% confidence level after some systematic Xmax shifting of the data. Three other QGSJet II-04 elements are found to be compatible using the same test procedure in an energy range limited to the highest energies where data statistics are sparse.
Najdeno v: ključnih besedah
Ključne besede: acceleration of particles, astrochemistry, astroparticle physics, cosmic rays, elementary particles, UHECR, composition
Objavljeno: 27.04.2020; Ogledov: 1705; Prenosov: 0
 Polno besedilo (5,52 MB) |
32. Telescope Array Composition SummaryJ. P. Lundquist, W. Hanlon, 2018, objavljeni znanstveni prispevek na konferenci Opis: Ultra high energy cosmic ray (UHECR) chemical composition is
important to resolving questions about the locations of UHECR
sources and propagation models. Because composition can only be
deduced by a process of statistical inference via the observation of air shower maxima (Xmax), UHECR observatories with large data
collection rates must be employed to reduce statistical
fluctuations. Telescope Array (TA), the largest cosmic ray
observatory in the Northern Hemisphere, is designed to answer the
question of UHECR composition, as well as other important features
of cosmic ray flux, by combining a large array of over 500
scintillation surface detectors spread over 700 km^2, and three
fluorescence detector stations overlooking the array. With eight
years of data recorded, results of the measurements of UHECR
composition will be presented. UHECR composition is traditionally
measured by comparing the first and second moments of the
distributions of shower maxima, which evolves with energy, between
data and simulations. Reducing statistical fluctuations in the data
helps to distinguish between different primary elements in the
flux. In the current generation of cosmic ray observatories, UHECR
data sets are large enough, and statistical uncertainties are now
small enough, that we can safely distinguish between very light
primary source flux (i.e., protons) and heavy flux (i.e.,
iron). Reducing systematic uncertainties is also important though,
since large systematic shifts in air shower maxima will influence
the interpretation of the data when compared to models. TA therefore employs different methods of measuring Xmax, including stereo air fluorescence, air fluorescence-surface counter hybrid, and a new technique using only surface counters. Updated results of TA hybrid composition among the different methods are presented using up to eight years of data. Agreement among all TA hybrid composition results are shown as well as detailed systematic errors which can be further explored by comparing composition results of the different measurement methods. Comparison of TA Xmax data are
compared to different composition models as well.
Najdeno v: ključnih besedah
Ključne besede: UHECR, Cosmic rays, composition
Objavljeno: 29.04.2020; Ogledov: 1299; Prenosov: 51
Polno besedilo (499,33 KB) |
33. Composition Measurements via Depth of Airshower Maximum at the Telescope ArrayW. Hanlon, J. P. Lundquist, 2018, objavljeni znanstveni prispevek na konferenci Opis: Telescope Array (TA) was designed to answer important questions about the UHECR flux with energies above 10^17 eV such as spectrum, arrival direction, and mass composition. Because the UHECR flux is rapidly falling in this energy region, TA’s large exposure makes it one of the few experiments in the world that can adequately explore these issues. Composition is particularly difficult to measure because mass can not be measured directly due to the low flux. TA’s multiple methods of observing UHECR induced air showers will be explained, as well as how composition can be measured by these methods. Good agreement among the different measurement techniques is found leading to greater confidence in measuring UHECR mass composition and a way to test and understand TA systematic uncertainties.
Najdeno v: ključnih besedah
Ključne besede: UHECR, cosmic rays, composition
Objavljeno: 29.04.2020; Ogledov: 1415; Prenosov: 65
Polno besedilo (758,27 KB) |
34. |
35. Report of the Working Group on the Composition of Ultra-High Energy Cosmic RaysJ. P. Lundquist, M. Unger, 2016, objavljeni znanstveni prispevek na konferenci Opis: The atmospheric depth, Xmax, at which the particle number of an air shower reaches its maximum is a good indicator for the mass of the primary particle. We present a comparison of the energy evolution of the mean of Xmax as measured by the Telescope Array and Pierre Auger Collaborations. After accounting for the different resolutions, acceptances and analysis strategies of the two experiments, the two results are found to be in good agreement within systematic uncertainties.
Najdeno v: ključnih besedah
Ključne besede: UHECR, cosmic rays, composition
Objavljeno: 29.04.2020; Ogledov: 1609; Prenosov: 50
Polno besedilo (329,86 KB) |
36. Mass Composition of Cosmic Rays with Energies above 10[sup]17.2 eV from the Hybrid Data of the Pierre Auger ObservatoryLukas Zehrer, Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Marta Trini, Samo Stanič, Gašper Kukec Mezek, Andrej Filipčič, Alexey Yushkov, 2019, objavljeni znanstveni prispevek na konferenci Najdeno v: ključnih besedah
Ključne besede: Pierre Auger Observatory, ultra-high energy cosmic rays (UHECR), UHECR hybrid detection, UHECR mass composition
Objavljeno: 21.12.2020; Ogledov: 1069; Prenosov: 37
Polno besedilo (749,44 KB) |
37. e/p separation study using the ISS-CREAM top and bottom counting detectorsY. Amarea, D. Angelaszek, S. C. Kang, N. Anthony, G. H. Choi, M. Chung, M. Copley, L. Derome, L. Eraud, C. Falana, Jon Paul Lundquist, 2019, objavljeni znanstveni prispevek na konferenci Opis: Cosmic Ray Energetics And Mass for the International Space Station (ISS-CREAM) is an experiment for studying the origin, acceleration, and propagation mechanisms of high-energy cosmic rays. The ISS-CREAM instrument was launched on the 14th of August 2017 to the ISS aboard the SpaceX-12 Dragon spacecraft. The Top and Bottom Counting Detectors (TCD/BCD) are parts of the ISS-CREAM instrument and designed for studying electron and gamma-ray physics. The TCD/BCD each consist of an array of 20 × 20 photodiodes on a plastic scintillator. The TCD/BCD can separate electrons from protons by using the difference between the shapes of electromagnetic and hadronic showers in the high energy region. The Boosted Decision Tree (BDT) method, which is a deep learning method, is used in this separation study. We will present results of the electron/proton separation study and rejection power in various energy ranges.
Najdeno v: ključnih besedah
Ključne besede: instrumentations, high energy cosmic rays, particle detectors, composition
Objavljeno: 08.02.2021; Ogledov: 1028; Prenosov: 0
Polno besedilo (2,14 MB) |
38. |
