The ARIANNA collaboration completed the installation of the hexagonal radio array (HRA) in December 2014, serving as a pilot program for a planned high energy neutrino telescope located about 110 km ...south of McMurdo Station on the Ross Ice Shelf near the coast of Antarctica. The goal of ARIANNA is to measure both diffuse and point fluxes of astrophysical neutrinos at energies in excess of 1016 eV. Upgraded hardware has been installed during the 2014 deployment season and stations show a livetime of better than 90% between commissioning and austral sunset. Though designed to observe radio pulses from neutrino interactions originating within the ice below each detector, one station was modified to study the low-frequency environment and signals from above. We provide evidence that the HRA observed both continuous emission from the Galaxy and a transient solar burst. Preliminary work on modeling the (weak) Galactic signal confirm the absolute sensitivity of the HRA detector system.
From an elevation of ~38 km, the balloon-borne ANtarctic Impulsive Transient Antenna (ANITA) is designed to detect the up-coming radio frequency (RF) signal resulting from a sub-surface ...neutrino-nucleon collision. Although no neutrinos have been discovered thus far, ANITA is nevertheless the only experiment to self-trigger on radio frequency emissions from cosmic-ray induced atmospheric air showers. In the majority of those cases, down-coming RF signals are observed via their reflection from the Antarctic ice sheet and back up to the ANITA interferometer. Estimating the energy scale of the incident cosmic rays therefore requires an estimate of the fractional power reflected at the air-ice interface. Similarly, inferring the energy of neutrinos interacting in-ice from observations of the upwards-directed signal refracting out to ANITA also requires consideration of signal coherence across the interface. By comparing the direct Solar RF signal intensity measured with ANITA to the surface-reflected Solar signal intensity, as a function of incident elevation angle relative to the surface {\Theta}, we estimate the power reflection coefficients R({\Theta}). We find general consistency between our average measurements and the values of R({\Theta}) expected from the Fresnel equations, separately for horizontal- vs. vertical-polarizations.
The Cosmic Ray Isotope Spectrometer (CRIS) experiment was launched aboard the NASA Advanced Composition Explorer satellite on August 25, 1997. The experimental objective of CRIS is to measure the ...isotopic composition of galactic cosmic ray nuclei for elements with charge 3<Z<28 over the energy range {approx}50-500 MeV/nuc. The instrument consists of a scintillating fiber hodoscope to determine particle trajectory, and four stacks of silicon wafers for multiple dE/dx and E{sub tot} measurements. This instrument is the first to use scintillating fibers in space. The CRIS instrument has a large geometrical factor of {approx}250 cm{sup 2} sr. The spatial resolution obtained by the fiber hodoscope is {approx}100 {mu}m. The mass resolution achieved is {approx}0.12 amu for Carbon and 0.30 amu for the heaviest isotopes measured. Mass histograms of selected isotopes are presented.
TIGER, the Trans-Iron Galactic Element Recorder, is a cosmic-ray balloon borne experiment that utilizes a scintillating Fiber Hodoscope/Time of Flight (TOF) counter. It was flown aboard a high ...altitude balloon on September 24, 1997. The objective of this experiment is to measure the elemental abundances of all nuclei within the charge range: 26{<=}Z{<=}40. This initial balloon flight will test the detector concept, which will be used in future balloon and space experiments. The instrument and the fiber detector are described.
X-ray polarimetry promises to give qualitatively new information about high-energy astrophysical sources, such as binary black hole systems, micro-quasars, active galactic nuclei, and gamma-ray ...bursts. We designed, built and tested a hard X-ray polarimeter, X-Calibur, to be used in the focal plane of the balloon-borne InFOCuS grazing incidence hard X-ray telescope. X-Calibur combines a low-Z Compton scatterer with a CZT detector assembly to measure the polarization of 20-60 keV X-rays making use of the fact that polarized photons Compton scatter preferentially perpendicular to the electric field orientation. The X-Calibur detector assembly is completed, tested, and calibrated; a first flight is scheduled from Ft. Sumner, NM, in fall 2014. In principal, a similar space-borne experiment could be operated in the 5-100 keV regime. X-Calibur achieves a high detection efficiency of order unity.
We have conducted a search for extended energy deposition trails left by ultra-relativistic magnetic monopoles interacting in Antarctic ice. The non-observation of any satisfactory candidates in the ...31 days of accumulated ANITA-II flight data results in an upper limit on the diffuse flux of relativistic monopoles. We obtain a 90% C.L. limit of order 10^{-19}/(cm^2-s-sr) for values of Lorentz boost factor 10^{10}<gamma at the anticipated energy E=10^{16} GeV. This bound is stronger than all previously published experimental limits for this kinematic range.
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