Characterizing radio emission from extensive air showers with the SLAC-T510 experiment, with applications to ANITA

• Main Author: Mulrey, Katharine B.
• Format: Thesis
• Language: English
• Published: University of Delaware 2018
• Subjects: Pure sciences; Cosmic rays; Neutrinos; Radio detection; Antarctic; Antarc*
• Online Access: http://udspace.udel.edu/handle/19716/23603

Neutrino and cosmic ray astronomy allow scientists to gather information about the highest energy processes in the universe. However, since cosmic rays are charged nuclei moving in astrophysical magnetic fields, it has not been possible to determine their sources by studying their arrival directions. A pointed neutrino flux is expected at such energies, either direct from the sources or due to the GZK process, where high energy cosmic rays interact with cosmic microwave photons as they travel through the universe. Detection methods make use of particle cascades initiated by these high energy primaries. In particular, the electromagnetic radiation in radio frequencies generated by particle cascades is a powerful tool. Particle cascades emit radiation by the Askaryan process, where a charge excess in the cascade emits coherently. In the presence of a magnetic field, a transverse current develops which also emits coherently in the radio regime. Theoretical models describe this radiation and are widely used to reconstruct the energy, geometry, and composition of observed events. Therefore, understanding and validating models describing this radiation is of great importance to neutrino and cosmic ray astronomy. ☐ The SLAC T-510 beam test is the first experiment to produce a particle cascade in a controlled setting in the presence of a magnetic field. Radio-frequency (RF) emission is collected in the region of the Cherenkov cone in two polarizations designed to separately capture Askaryan and magnetically induced radiation. Field intensity, linearity with magnetic field, and spectral content are compared to particle-level simulations. The data provide experimental evidence supporting theoretical models, and show the first laboratory results of the scaling of the radiative strength with the magnetic field. ☐ SLAC T-510 grew out of a need to calibrate the sensitivity of the ANITA (Antarctic Impulsive Transient Antenna) experiment to cosmic ray air showers. ANITA uses radio techniques to detect the highest energy ...