Dr. Kimberly Palladino

Abstract:

We report on observations of coherent, impulsive radio Cherenkov radiation from electromagnetic showers in solid ice. This is the first observation of the Askaryan effect in ice. As part of the complete validation process for the ANITA experiment, we performed an experiment at the Stanford Linear Accelerator Center in June 2006 using a 7.5 metric ton ice target. We measure for the first time the large-scale angular dependence of the radiation pattern, a major factor in determining the solid-angle acceptance of ultrahigh-energy neutrino detectors.

Abstract:

The ANtarctic Impulsive Transient Antenna (ANITA) searches for ultra high energy neutrinos interacting in the Antarctic ice cap. It is a long duration balloon experiment composed of an array of broadband dual-polarized horn antennas that had its first science flight over Antarctica in December 2006 through January 2007. ANITA relies upon the Askaryan effect, in which a particle shower in a dense medium emits coherent Cherenkov radiation at radio wavelengths, for the detection of a neutrino induced shower. ANITA is designed to detect-or constrain flux models of-ultra high energy neutrinos created by the interaction of ultra high energy cosmic rays with the cosmic microwave background. In this paper we discuss the detector performance during the first ANITA flight.

Abstract:

The balloon-borne ANITA neutrino telescope successfully launched from McMurdo Station, Antarctica during the 2006-2007 austral summer. In this paper we present ongoing studies of the energy resolution and system response of the ANITA detector, which provide an excellent test bed for validating the ANITA Monte Carlo and will be of great interest if ANITA discovers signal events. While in view of the launch site ANITA received calibration pulses from two antennas, located on the surface and in a borehole in the Ross Ice Shelf, which facilitate these studies.

Abstract:

The ANITA (Antarctic Impulsive Transient Antenna) experiment may be the first experiment to identify astrophysical neutrinos of energy greater than 1018 eV. A Monte Carlo simulation has been developed to determine the sensitivity and improve the event reconstruction capabilities of ANITA at energies up to 1021 eV. Charged leptons created in charged current neutrino-nucleon interactions can produce secondary showers when they experience hard energy losses through bremsstrahlung, pair production, and photonuclear interactions as they propagate through the ice. Because the cross sections of these interactions depend on the flavor and energy of the charged lepton, the distribution of the showers can indicate the flavor and energy of the neutrino. Results from the simulation are presented.