LUX-ZEPLIN

Abstract:

The Antarctic Impulsive Transient Antenna (ANITA) experiment is being developed to search for ultra-high-energy (UHE) neutrino interactions ($>3\times10^{18}$ eV) in the Antarctic ice cap. A neutrino interaction in the ice will produce a radio pulse by the means of the Askaryan effect. The large radio transparency of ice allows for such a pulse to be recorded by a cluster of balloon-borne antennas. The details of the ANITA instrument, now in a construction phase, and the science we hope to achieve is discussed. In order to prepare for the main mission, we have flown ANITA-lite during the 2003/04 austral season. ANITA-lite consisted of two quad-ridge horn antennas and a prototype RF (radio frequency) triggering and recording system. Here we present the results of an impulsive RF background survey of Antarctica, as well as proof-of-principle gain, tracking, and timing calibrations conducted by observing solar radio emissions and calibration radio-pulses. A preliminary UHE neutrino flux limit based on ANITA-lite data is also presented.

Abstract:

In this study, we examined the luminescence response of Ti-doped Al2 O3 crystals to high-energy vacuum ultraviolet (UV) excitation. In addition to the thoroughly studied emission band of Ti3+ in the near-infrared region and blue emission at 420 nm, we detected a UV emission band at 290 nm. The excitation spectra of all emission bands were measured over the 4-20 eV spectral range. Our results indicate that intrinsic anion defects are involved in the process of the excitation of the 420 nm emission assigned to the charge transfer transitions 2p O2- →3d Ti4+. Analysis of the spectral and decay characteristics of the UV emission enables us to suggest that this band is associated with radiative decay of excitons localized at Ti ions. © 2005 American Institute of Physics.