Bulletin of the American Physical Society
2009 APS April Meeting
Volume 54, Number 4
Saturday–Tuesday, May 2–5, 2009; Denver, Colorado
Session D8: Ultra-High Energy Cosmic Ray Instruments |
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Sponsoring Units: DAP Chair: Stefan Westerhoff, University of Wisconsin-Madison Room: Governor's Square 17 |
Saturday, May 2, 2009 3:30PM - 3:42PM |
D8.00001: Physics of the Telescope Array Experiment Pierre Sokolsky The Telescope Array (TA) experiment has as its aim studying ultrahigh energy cosmic rays. It consists of a surface detector (SD) of 512 scintillation counters and three fluorescence detectors overlooking the SD. The experiment is located in Millard County, Utah, and is the largest in the northern hemisphere. In this talk a description will be given of the experiment and its physics aims. [Preview Abstract] |
Saturday, May 2, 2009 3:42PM - 3:54PM |
D8.00002: The Fluorescence Detectors of the Telescope Array Experiment Lauren Scott The Telescope Array (TA), the first dedicated Northern Hemisphere ``hybrid'' ultrahigh energy cosmic ray (UHECR) detector, is online in Millard Country, Utah. The three Fluorescence Detector sites (FD) located at Black Rock Mesa, Long Ridge and Middle Drum have been taking data since November 2007. By measuring the characteristics of UHECR-induced extensive air showers using the FD, we can measure the energies, composition and arrival directions of the highest-energy cosmic rays. We will show preliminary data from the experiment and comparisons with simulated data from our full detector Monte Carlo simulation program. [Preview Abstract] |
Saturday, May 2, 2009 3:54PM - 4:06PM |
D8.00003: The Telescope Array's Low Energy Extension: TALE John Matthews A great deal of information about the sources of ultra high energy cosmic rays exists encoded in the energy spectrum. There are three spectral features in the ultra high energy regime (the second knee, the ankle, and the GZK cut-off). An important composition change also occurs in this energy range. The Telescope Array (TA) is a large area ultra high energy cosmic ray observatory built and operated by groups from the US, Japan, Korea, and Russia. The existing part of the Telescope Array already has good efficiency above the ankle ($\sim $10$^{18.5}$ eV). These detectors are already in the field collecting data. The TA Low Energy Extension (TALE) refers to the detectors devoted to the ``low energy'' portion of the spectrum - 10$^{16.5}$ - 10$^{19}$ eV. The aim of TA/TALE is to understand the origin of cosmic rays and to study their composition over a broad energy range. We will introduce the detector components and discuss the opportunities. [Preview Abstract] |
Saturday, May 2, 2009 4:06PM - 4:18PM |
D8.00004: The TALE Infill Array Douglas Bergman The TALE Infill Array in conjunction with the TALE Tower Detector will provide hybrid coverage of the cosmic ray energy spectrum down to $3\times10^{16}$ eV. It will consist of about 100, two square meter scintillators on the surface spaced at 400 m; and 24 buried twelve square meter scintillators. The combination of surface and underground detectors will allow for the determination of the muon content of showers and thus give a handle on cosmic ray composition. [Preview Abstract] |
Saturday, May 2, 2009 4:18PM - 4:30PM |
D8.00005: The TALE Fluorescence Detectors Charles Jui The TALE fluorescence detectors are designed to extend the threshold for fluorescence observation by TA down to 3x10$^{16}$ eV. It will comprise two main components. The first is a set of 24 telescopes working in stereo, with an existing TA FD station at $\sim $6 km separation. These will cover between 3-31 degrees in elevation and have azimuthal coverage maximizing the stereo aperture in the 10$^{18}$-10$^{19}$ eV energy range. The second component consists of 15 telescopes equipped with 4m diameter mirrors and covering the sky between 31 and 73 degrees in elevation. The larger mirror size pushes the physics threshold down to 3x10$^{16}$ eV, and provides view of the shower maximum for the lower energy events. The Tower detector will cover one quadrant in azimuth and operate in hybrid mode with the TALE infill array to provide redundant composition measurements from both shower maximum information and muon-to-electron ratio. [Preview Abstract] |
Saturday, May 2, 2009 4:30PM - 4:42PM |
D8.00006: Using laser shots to determine the speed resolution of air showers at the southern Pierre Auger observatory Kathleen Gesterling, Fred Sarazin, Lawrence Wiencke Laser shots from the Central Laser Facility (CLF) at the Southern Pierre Auger Observatory are used to simulate the signal received by the Fluorescence Detectors (FDs) from extensive air showers. Because the geometry of the CLF and the FDs is known, it is possible to fit the time profile recorded in the FDs using the ``shower'' speed as a free parameter. In this test case, the analysis of a collection of laser shots allowed us to determine with which precision and accuracy we were able to re-measure the speed of light. By using stereo or hybrid events, a modified algorithm accounting for real cosmic ray showers may be able to identify objects propagating significantly below the speed of light. [Preview Abstract] |
Saturday, May 2, 2009 4:42PM - 4:54PM |
D8.00007: Mission preparation status of Extreme Universe Space Observatory (EUSO) on Japanese Experiment Module (JEM) of International Space Station (ISS) Yoshiyuki Takahashi JEM-EUSO is an international mission that is designed to identify the astronomical origin of extreme energy cosmic ray particles with energies $>$10$^{20}$ eV. Its instrument uses a near-UV telescope with the diameter of 2.5-m and the field-of-view of 60-degrees for the detection of fluorescence and Cherenkov light along the linear track of a cosmic ray event in atmosphere. JEM-EUSO can detect at least 1,000 particles above 7 x 10$^{19}$ eV in a three year mission for the least expected flux by Greisen-Zatsepin-Kuzmin cutoff. Their energy and arrival direction will be accurately measured while all-sky is covered and monitored. These data will be used to identify the sources of the highest-energy particles including neutrinos and clarify their origin. The Japan Experiment Module (JEM) on the International Space Station (ISS) will host JEM-EUSO. Whereas an ordinary astronomical observatory looks up at the universe from earth, JEM-EUSO observes the universe by looking toward the earth because the earth's atmosphere is the largest detector yet employed in our quest to understand the origins of these elusive particles coming from the universe JEM-EUSO is a new type of astronomical space observatory, namely, an ``earth-observing'' astronomical telescope. [Preview Abstract] |
Saturday, May 2, 2009 4:54PM - 5:06PM |
D8.00008: Weather effects on the rate of events at the Pierre Auger Observatory Adrienne Criss, Paul Sommers The Pierre Auger Observatory studies high energy cosmic rays using both a surface detector and a florescence detector. Correcting for weather-induced rate variations is essential before searching for large scale anisotropy patterns. Additionally, weather-induced rate variations may yield clues to the nuclear mass composition of the primary cosmic rays. Here we present how the rate of events (defined as the number of events recorded divided by the exposure) of the surface detector varies with the atmospheric pressure and temperature measured at ground level. We examine the rate dependence on weather at different zenith angles and energies. [Preview Abstract] |
Saturday, May 2, 2009 5:06PM - 5:18PM |
D8.00009: Extensive air shower simulation: $10^{19}$ eV and beyond Benjamin Stokes The history of ultra-high energy cosmic ray observation is now approaching 50 years. However, until quite recently, the full simulation of an extensive air shower was computationally impossible due to the vast quantity of daughter particles involved. However, with the advent of modern cluster computing, simulations that once would have taken years to complete can be done in a matter of hours or even minutes. Full shower simulations produced by a parallelization scheme employing the Karlsruhe Extensive Air Shower Simulation Code (CORSIKA) will be presented in conjunction with a ``dethinning'' technique that attempts to recover information lost by the CORSIKA statistical thinning algorithm. [Preview Abstract] |
Saturday, May 2, 2009 5:18PM - 5:30PM |
D8.00010: Updates on IceCube's Radio Frequency extension Dave Besson The radio frequency (RF) transparency of cold ice makes it an excellent medium for an ultra-high energy neutrino detector. Detector modules can be sparsely deployed at shallower depths, covering a large volume at low cost. In the last three years, RF detectors have been deployed in the Antarctic ice as an enhancement to the optically-based IceCube Neutrino Observatory, as a step towards a large-scale cosmogenic (or ``GZK'') neutrino detector. During the recent Antarctic summer (2008-2009), three additional antenna clusters were deployed at depths of 300 to 1400 meters. We will discuss the status of the detector development and show preliminary results from IceCube's RF extension (often referred to as ``AURA: the Askaryan Under-ice Radio Array''). [Preview Abstract] |
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