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Author: Philip Wahrlich Publisher: ISBN: Category : Cosmic rays Languages : en Pages : 480
Book Description
"The Pierre Auger Observatory (PAO) was constructed to study the highest energy cosmic rays (UHECR). A hybrid of ground array and fluorescence detector, it is the largest ultra-high energy cosmic ray detector to date. As such, the PAO detects UHECR in unprecedented amounts, offering unique insights into the nature and origin of these most extraordinarily energetic particles in the universe. In this thesis we improve the accuracy of arrival direction uncertainty estimates for reconstructed events. We validate these improved uncertainty estimators through a number of statistical techniques, involving both recorded and simulated data. Furthermore, we identify and correct a number of systematic errors which arise in algorithmic corner cases. We propose novel techniques for measuring the time synchronisation of each detector in the using recorded air shower data. We use these techniques to measure the synchronisation of each detector across the PAO surface detector and fluorescence detector. Finally, we perform a cursory search for a point source of UHECR at the Galactic centre. A slight over-density of events is measured from the direction of the Galactic centre, however this over-density is not substantial enough to indicate a departure from isotropy." -- page 12.
Author: Philip Wahrlich Publisher: ISBN: Category : Cosmic rays Languages : en Pages : 480
Book Description
"The Pierre Auger Observatory (PAO) was constructed to study the highest energy cosmic rays (UHECR). A hybrid of ground array and fluorescence detector, it is the largest ultra-high energy cosmic ray detector to date. As such, the PAO detects UHECR in unprecedented amounts, offering unique insights into the nature and origin of these most extraordinarily energetic particles in the universe. In this thesis we improve the accuracy of arrival direction uncertainty estimates for reconstructed events. We validate these improved uncertainty estimators through a number of statistical techniques, involving both recorded and simulated data. Furthermore, we identify and correct a number of systematic errors which arise in algorithmic corner cases. We propose novel techniques for measuring the time synchronisation of each detector in the using recorded air shower data. We use these techniques to measure the synchronisation of each detector across the PAO surface detector and fluorescence detector. Finally, we perform a cursory search for a point source of UHECR at the Galactic centre. A slight over-density of events is measured from the direction of the Galactic centre, however this over-density is not substantial enough to indicate a departure from isotropy." -- page 12.
Author: Publisher: ISBN: Category : Languages : en Pages : 20
Book Description
We present a comprehensive study of the influence of the geomagnetic field on the energy estimation of extensive air showers with a zenith angle smaller than 60{sup o}, detected at the Pierre Auger Observatory. The geomagnetic field induces an azimuthal modulation of the estimated energy of cosmic rays up to the ≈ 2% level at large zenith angles. We present a method to account for this modulation of the reconstructed energy. We analyse the effect of the modulation on large scale anisotropy searches in the arrival direction distributions of cosmic rays. At a given energy, the geomagnetic effect is shown to induce a pseudo-dipolar pattern at the percent level in the declination distribution that needs to be accounted for. In this work, we have identified and quantified a systematic uncertainty affecting the energy determination of cosmic rays detected by the surface detector array of the Pierre Auger Observatory. This systematic uncertainty, induced by the influence of the geomagnetic field on the shower development, has a strength which depends on both the zenith and the azimuthal angles. Consequently, we have shown that it induces distortions of the estimated cosmic ray event rate at a given energy at the percent level in both the azimuthal and the declination distributions, the latter of which mimics an almost dipolar pattern. We have also shown that the induced distortions are already at the level of the statistical uncertainties for a number of events N ≃ 32 000 (we note that the full Auger surface detector array collects about 6500 events per year with energies above 3 EeV). Accounting for these effects is thus essential with regard to the correct interpretation of large scale anisotropy measurements taking explicitly profit from the declination distribution.
Author: Publisher: ISBN: Category : Languages : en Pages : 128
Book Description
Anisotropy in the cosmic-ray arrival direction distribution has been well documented over a large energy range, but its origin remains largely a mystery. In the TeV to PeV energy range, the galactic magnetic field thoroughly scatters cosmic rays, but anisotropy at the part-per-mille level and smaller persists, potentially carrying information about nearby cosmic-ray accelerators and the galactic magnetic field. The IceCube Neutrino Observatory was the first detector to observe anisotropy at these energies in the Southern sky. This work uses 318 billion cosmic-ray induced muon events, collected between May 2009 and May 2015 from both the in-ice component of IceCube as well as the surface component, IceTop. The observed global anisotropy features large regions of relative excess and deficit, with amplitudes on the order of $10^{-3}$. While a decomposition of the arrival direction distribution into spherical harmonics shows that most of the power is contained in the low-multipole ($\ell \leq 4$) moments, higher-multipole components are found to be statistically significant down to an angular scale of less than $10^{\circ}$, approaching the angular resolution of the detector. Above 100\,TeV, a change in the topology of the arrival direction distribution is observed, and the anisotropy is characterized by a wide relative deficit whose amplitude increases with primary energy up to at least 5\,PeV, the highest energies currently accessible to IceCube with sufficient event statistics. No time dependence of the large- and small-scale structures is observed in the six-year period covered by this analysis within statistical and systematic uncertainties. Analysis of the energy spectrum and composition in the PeV energy range as a function of sky position is performed with IceTop data over a five-year period using a likelihood-based reconstruction. Both the energy spectrum and the composition distribution are found to be consistent with a single source population over declination bands. This work represents an early attempt at understanding the anisotropy through the study of the spectrum and composition. The high-statistics data set reveals more details on the properties of the anisotropy, potentially able to shed light on the various physical processes responsible for the complex angular structure and energy evolution.
Author: Claus Grupen Publisher: Springer Science & Business Media ISBN: 3642132715 Category : Science Languages : en Pages : 1251
Book Description
The handbook centers on detection techniques in the field of particle physics, medical imaging and related subjects. It is structured into three parts. The first one is dealing with basic ideas of particle detectors, followed by applications of these devices in high energy physics and other fields. In the last part the large field of medical imaging using similar detection techniques is described. The different chapters of the book are written by world experts in their field. Clear instructions on the detection techniques and principles in terms of relevant operation parameters for scientists and graduate students are given.Detailed tables and diagrams will make this a very useful handbook for the application of these techniques in many different fields like physics, medicine, biology and other areas of natural science.
Author: Publisher: ISBN: Category : Languages : en Pages : 15
Book Description
Energy-dependent patterns in the arrival directions of cosmic rays are searched for using data of the Pierre Auger Observatory. We investigate local regions around the highest-energy cosmic rays with $E \ge 6 \times 10^$ eV by analyzing cosmic rays with energies above $E \ge 5 \times 10^$ eV arriving within an angular separation of approximately 15$^{\circ }$ . We characterize the energy distributions inside these regions by two independent methods, one searching for angular dependence of energy-energy correlations and one searching for collimation of energy along the local system of principal axes of the energy distribution. No significant patterns are found with this analysis. The comparison of these measurements with astrophysical scenarios can therefore be used to obtain constraints on related model parameters such as strength of cosmic-ray deflection and density of point sources.
Author: F. Meyer Publisher: ISBN: Category : Languages : en Pages : 4
Book Description
Reconstruction of cosmic ray arrival directions for Surface Detectors (SD) and Fluorescence Detectors (FD) of the Pierre Auger Observatory requires accurate timing (25 nanoseconds or better) between measurements at individual detectors and instrument triggers. Timing systems for both SD and FD are based on Motorola Oncore UT+ GPS receivers installed into custom-built time-tagging circuits that are calibrated in the laboratory to a statistical precision of better than 15 ns. We describe timing calibration and synchronization methods applied in the field for both the SD and the FD systems in four areas: (1) checks of timing offsets within the SD using co-located station pairs and timing residuals on reconstructed showers, (2) calibration within the FD using a custom-build LED calibration system, (3) calibration between SD and FD using laser signals fed simultaneously into an SD station and across the FD via the Central Laser Facility (CLF), and (4) studies of synchronization between FD and SD through the analysis of events detected by both systems, called hybrid events. These hybrid events allow for a much more accurate reconstruction of the shower and for relatively tight constraints on timing calibration offsets. We demonstrate that statistical and systematic timing uncertainties have no significant impact on the event reconstruction.
Author: Pierre Sokolsky Publisher: World Scientific ISBN: 1800612621 Category : Science Languages : en Pages : 323
Book Description
The universe is pervaded by particles with extreme energies, millions of times greater than we can produce on Earth. They have been a mystery for over a century. Now, current and future experiments in particle astrophysics are leading us to answers to the most fundamental questions about them. How does nature accelerate the highest energy particles in the universe? Do new interactions between them occur at such extreme energies? Are there unknown aspects of spacetime that can be uncovered by studying these particles?This book brings together three fields within 'extreme astronomy': ultra-high-energy cosmic ray physics, neutrino astronomy, and gamma-ray astronomy, and discusses how each can help answer these questions. Each field is presented with a theoretical introduction that clearly elucidates the key questions scientists face. This is followed by chapters that discuss the current set of experiments — how they work and their discoveries. Finally, new techniques and approaches are discussed to solve the mysteries uncovered by the current experiments.
Author: Claudia Cecchi Publisher: World Scientific ISBN: 9814480711 Category : Science Languages : en Pages : 561
Book Description
The International Conference on Calorimetry in Particle Physics is the major and most comprehensive forum for discussion on state-of-the-art developments of calorimetry technologies. The Eleventh Conference covered all aspects of calorimetric detection and measurements, with emphasis on high energy physics and astrophysics experiments. Besides the usual discussion on calorimetry technologies this edition is enriched by the presence of two sections dedicated to new techniques for calorimetry and applications to calorimetry for the next Linear Collider experiments.
Author: Maurice M Shapiro Publisher: World Scientific ISBN: 9814472093 Category : Science Languages : en Pages : 239
Book Description
This book introduces young researchers to the exciting field of ultra-high energy astrophysics including charged particles, gamma rays and neutrinos. At ultra-high energy the radiation is produced by interactions of cosmic ray particles accelerated in explosive events such as supernovae or hypernovae, black holes or, possibly, the big bang. Through direct contact with senior scientists, now actively planning the next generation of experiments/models, the excitement and motivation for research at ultra-high energy was conveyed. The underpinning of these fields is a synthesis of knowledge and techniques from nuclear and particle physics, astronomy and cosmology. Informing the participants of this background, how it was derived, and the new challenges for the future are the major goal. Further, the course has helped to foster new astrophysical research and promoted contacts, which have resulted in new collaborations.
Author: Richard Brenner Publisher: World Scientific ISBN: 9814478563 Category : Science Languages : en Pages : 530
Book Description
The Lepton-Photon symposiums — as represented by the contributions in this volume — are among the most popular conferences in high energy physics since they give an in-depth snapshots of the status of the field as provided by leading experts.The volume covers the latest results on flavor factories, quantum chromodynamics (QCD), electroweak physics, dark matter searches, neutrino physics and cosmology, from a phenomenological point of view. It also offers a glimpse of the immediate future of the field through summaries on the status of the next generation of high energy accelerators and planned facilities for astroparticle physics.The review nature of the articles makes the volume particularly useful to students, as well as being of interest to established researches in high-energy physics and related fields.
Author: Philip Wahrlich
Author: Philip Wahrlich
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Author: 
Author: Claus Grupen
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Author: F. Meyer
Author: Pierre Sokolsky
Author: Claudia Cecchi
Author: Maurice M Shapiro
Author: Richard Brenner