Modeling and Validating RF-Only Interferometric Triggering with Cosmic Rays for BEACON

Abstract

When Earth-skimming tau neutrinos interact within the Earth, they generate upgoing tau leptons that can decay in the atmosphere, forming extensive air showers. The Beamforming Elevated Array for COsmic Neutrinos (BEACON) is a novel detector concept that utilizes a radio interferometer atop a mountain to search for the radio emission due to these extensive air showers. The prototype, located at the White Mountain Research Station in California, consists of 4 crossed-dipole antennas operating in the 30-80 MHz range and uses a directional interferometric trigger for reduced thresholds and background rejection. The prototype will first be used to detect down-going cosmic rays to validate the detector model. A Monte-Carlo simulation was developed to predict the acceptance of the prototype to cosmic rays, as well as the expected rate of detection. In this simulation, cosmic ray induced air showers with random properties are generated in an area around the prototype array. It is then determined if a given shower triggers the array using radio emission simulations from ZHAireS and antenna modelling from XFdtd. Here, we present the methodology and results of this simulation.

High-Energy and Ultra-High-Energy Neutrinos

“…While the prototype is too small to search for tau neutrinos, the technique can be tested thoroughly through searches for cosmic rays at high zenith angles [669]. A cosmic-ray search is underway currently [670], and with the observed flux, the projected neutrino sensitivity will be trained on the measured trigger threshold in situ.…”

Design and Initial Performance of the Prototype for the BEACON Instrument for Detection of Ultrahigh Energy Particles

“…Thresholds are computed as the power sum over a 16 sample (32 ns) window in each beam and are shown here referenced to the RMS noise in a beam, which is monitored continuously by the DAQ. On the bottom of Figure 11, the beam power SNR thresholds are compared to the beam voltage SNR thresholds in the beams, computed from simulations of cosmic rays modeled with ZHAireS and propagated through the prototype signal chain [60]. This comparison arrives at a beam voltage SNR threshold which approaches the thresholds assumed in the tau neutrino sensitivity study (5 ) [20].…”

“…We expect a few cosmic ray events per day to trigger the prototype given nominal beam voltage SNR thresholds of 5 [60]. Cosmic ray candidates will appear as isolated above-horizon events that are not identifiable as RFI events and do not cluster spatially or temporally.…”

“…Figure 20 shows the waveform from the event of interest alongside an event waveform generated with the cosmic ray simulation [60] and compares the observed linear polarization angle and arrival direction with simulated distributions. The tangent of the polarization angle is calculated as the ratio of the maximum of the aligned and averaged de-dispersed waveforms in VPol to HPol when upsampled and symmetric filtering is applied across polarizations (such that VPol is filtered with the TV notch filter as well, ensuring similar power is lost in both averaged waveforms and a representative ratio is preserved).…”

Rapporteur ICRC 2021: Neutrinos and Muons

“…There are various proposed radio air shower arrays in pathfinder mode aiming at the detection of through -induced air showers. To this end, one can either blanket large areas with simple antennas as proposed for GRAND [14,15] or one can set-up smaller arrays on mountain tops overlooking large areas, like proposed for BEACON [16,17] or TAROGE [18]. Demonstrators for both approaches are currently operational.…”