19 research outputs found
Prospects for High-Elevation Radio Detection of >100 PeV Tau Neutrinos
Tau neutrinos are expected to comprise roughly one third of both the
astrophysical and cosmogenic neutrino flux, but currently the flavor ratio is
poorly constrained and the expected flux at energies above eV is low.
We present a detector concept aimed at measuring the diffuse flux of tau
neutrinos in this energy range via a high-elevation mountaintop detector using
the radio technique. The detector searches for radio signals from upgoing air
showers generated by Earth-skimming tau neutrinos. Signals from several
antennas in a compact array are coherently summed at the trigger level,
permitting not only directional masking of anthropogenic backgrounds, but also
a low trigger threshold. This design takes advantage of both the large viewing
area available at high-elevation sites and the nearly full duty cycle available
to radio instruments. We present trade studies that consider the station
elevation, frequency band, number of antennas in the array, and the trigger
threshold to develop a highly efficient station design. Such a mountaintop
detector can achieve a factor of ten improvement in acceptance over existing
instruments with 100 independent stations. With 1000 stations and three years
of observation, it can achieve a sensitivity to an integrated
flux of GeV cm sr s, in the
range of the expected flux of all-flavor cosmogenic neutrinos assuming a pure
iron cosmic-ray composition.Comment: 26 pages, 11 figure
Design and Initial Performance of the Prototype for the BEACON Instrument for Detection of Ultrahigh Energy Particles
The Beamforming Elevated Array for COsmic Neutrinos (BEACON) is a planned
neutrino telescope designed to detect radio emission from upgoing air showers
generated by ultrahigh energy tau neutrino interactions in the Earth. This
detection mechanism provides a measurement of the tau flux of cosmic neutrinos.
We have installed an 8-channel prototype instrument at high elevation at
Barcroft Field Station, which has been running since 2018, and consists of 4
dual-polarized antennas sensitive between 30-80 MHz, whose signals are
filtered, amplified, digitized, and saved to disk using a custom data
acquisition system (DAQ). The BEACON prototype is at high elevation to maximize
effective volume and uses a directional beamforming trigger to improve
rejection of anthropogenic background noise at the trigger level. Here we
discuss the design, construction, and calibration of the BEACON prototype
instrument. We also discuss the radio frequency environment observed by the
instrument, and categorize the types of events seen by the instrument,
including a likely cosmic ray candidate event.Comment: 21 pages, 20 figure
Energy and Flux Measurements of Ultra-High Energy Cosmic Rays Observed During the First ANITA Flight
The first flight of the Antarctic Impulsive Transient Antenna (ANITA)
experiment recorded 16 radio signals that were emitted by cosmic-ray induced
air showers. For 14 of these events, this radiation was reflected from the ice.
The dominant contribution to the radiation from the deflection of positrons and
electrons in the geomagnetic field, which is beamed in the direction of motion
of the air shower. This radiation is reflected from the ice and subsequently
detected by the ANITA experiment at a flight altitude of 36km. In this paper,
we estimate the energy of the 14 individual events and find that the mean
energy of the cosmic-ray sample is 2.9 EeV. By simulating the ANITA flight, we
calculate its exposure for ultra-high energy cosmic rays. We estimate for the
first time the cosmic-ray flux derived only from radio observations. In
addition, we find that the Monte Carlo simulation of the ANITA data set is in
agreement with the total number of observed events and with the properties of
those events.Comment: Added more explanation of the experimental setup and textual
improvement