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.

Abstract:

Reflection, emission and luminescence spectra of Czochralski grown molybdate crystals, i.e. MgMoO4, CaMoO4 and CdMoO 4 have been investigated over a 8-295 K temperature range using VUV synchrotron radiation. Preliminary interpretation of the spectroscopic properties has been carried out on the basis of present knowledge of the electronic structure and emission properties of these materials. The results of this study support the conclusion that molybdate crystals have good prospect for application in the search for rare events as cryogenic phonon-scintillation detectors. © 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.