First Upper Limits on the Radar Cross Section of Cosmic-Ray Induced Extensive Air Showers

Abstract

TARA (Telescope Array Radar) is a cosmic ray radar detection experiment colocated with Telescope Array, the conventional surface scintillation detector (SD) and fluorescence telescope detector (FD) near Delta, Utah, U.S.A. The TARA detector combines a 40 kW, 54.1 MHz VHF transmitter and high-gain transmitting antenna which broadcasts the radar carrier over the SD array and within the FD field of view, towards a 250 MS/s DAQ receiver. TARA has been collecting data since 2013 with the primary goal of observing the radar signatures of extensive air showers (EAS). Simulations indicate that echoes are expected to be short in duration (~10 microseconds) and exhibit rapidly changing frequency, with rates on the order of 1 MHz/microsecond. The EAS radar cross-section (RCS) is currently unknown although it is the subject of over 70 years of speculation. A novel signal search technique is described in which the expected radar echo of a particular air shower is used as a matched filter template and compared to waveforms obtained by triggering the radar DAQ using the Telescope Array fluorescence detector. No evidence for the scattering of radio frequency radiation by EAS is obtained to date. We report the first quantitative RCS upper limits using EAS that triggered the Telescope Array Fluorescence Detector.

21 pages, 30 figures

References in corpus (4)

• Big-Bang Nucleosynthesis
• 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
• The Cosmic Ray Energy Spectrum Observed with the Surface Detector of the Telescope Array Experiment
• Telescope Array Radar (TARA) Observatory for Ultra-High Energy Cosmic Rays

Cited by in corpus (9)

• Observation of Radar Echoes From High-Energy Particle Cascades
• New Constraints on Macroscopic Dark Matter Using Radar Meteor Detectors
• Suggestion of Coherent Radio Reflections from an Electron-Beam Induced Particle Cascade
• The Radar Echo Telescope for Cosmic Rays: Pathfinder Experiment for a Next-Generation Neutrino Observatory
• Implementation of a custom time-domain firmware trigger for RADAR-based cosmic ray detection
• Past, Present and Future of UHECR Observations
• Complex Analysis of Askaryan Radiation: A Fully Analytic Model in the Time-Domain
• Particle-level model for radar based detection of high-energy neutrino cascades
• Macroscopic approach to the radar echo scatter from high-energy particle cascades