arXiv subjects

Shoukat Ali

Publications and source records attributed to Shoukat Ali.

3 recordsLinked to original sources

arXiv2026

The Study of a Cosmic Ray Candidate Detected by the Askaryan Radio Array

Experiments designed to detect ultra-high energy (UHE) neutrinos using radio techniques are also capable of detecting the radio signals from cosmic-ray (CR) induced air showers. These CR signals are important both as a background and as a tool for calibrating the detector. The Askaryan Radio Array (ARA), a radio detector array, is designed to detect UHE neutrinos. The array currently comprises five independent stations, each instrumented with antennas deployed at depths of up to 200 meters within the ice at the South Pole. In this study, we focus on a candidate event recorded by ARA Station 2 (A2) that shows features consistent with a downward-going CR-induced air shower. This includes distinctive double-pulse signals in multiple channels, interpreted as geomagnetic and Askaryan radio emissions arriving at the antennas in sequence. To investigate this event, we use detailed simulations that combine a modern ice-impacting CR shower simulation framework, FAERIE, with a realistic detector simulation package, AraSim. We will present results for an optimization of the event topology, identified through simulated CR showers, comparing the vertex reconstruction of both the geomagnetic and Askaryan signals of the event, as well as the observed time delays between the two signals in each antenna.

astro-ph.IM↗

arXiv2025

Development of a Custom kV-amplitude, pressure-tolerant Radio-Frequency transmitter

Current experiments seeking first-ever observation of Ultra-High Energy Neutrinos (UHEN) typically utilize radio frequency (RF) receiver antennas deployed in cold, radio-transparent polar ice, to measure the coherent RF signals resulting from neutrino interactions with ice molecules. Accurate calibration of the receiver response, sampling the full range of possible neutrino geometries, is necessary to estimate the energy and incoming direction of the incident neutrino. Herein, we detail the design and performance of a custom radio-frequency calibration transmitter, consisting of a battery-powered, kiloVolt-scale signal generator (`IDL' pulser) driving an antenna (South Pole UNiversity of Kansas antenna, or `SPUNK') capable of operating at pressures of 200 atmospheres. Performance was validated by lowering the transmitter into a borehole at the South Pole to a depth of 1740 m, yielding high Signal-to-Noise ratio signals at a distance of 5 km from the source.

astro-ph.IM↗

arXiv2025

Study of an Isolated Double-pulse Cosmic Ray Candidate Recorded with the Askaryan Radio Array

The radio-frequency emissions produced by particle showers on Earth, resulting from cosmic rays (CRs) and ultra-high energy neutrinos (UHE-$\nu$) originating from astrophysical sources share significant similarities, enabling radio detectors initially designed for UHE-$\nu$ searches to also study CRs. The Askaryan Radio Array (ARA), an experiment currently operating within the ice at the South Pole, is primarily designed to detect UHE-$\nu$s. To date, ARA has deployed five stations, with each station equipped with antennas installed at depths up to 200 meters in the ice. Data recorded by ARA Station-2 (A2) suggest a potential CR origin for a subset of events identified in a UHE-$\nu$ search. This subset includes a double-pulse event potentially from a downward propagating CR-induced air shower, with in-air geomagnetic emission followed by in-ice Askaryan emission producing the two pulses. A detailed investigation of this CR candidate event using comprehensive simulations has been conducted with the goal of identifying the parameters of a CR-induced air shower that best match the experimentally observed quantities. We simulate predicted CR signals in ARA by combining an impacting CR shower simulation framework (FAERIE) with a realistic detector simulation (AraSim). We determine the event topology based on the vertex reconstruction of both the putative geomagnetic and Askaryan signals. After inferring the event geometry, we show that the simulation matches the observed time structure of the event (channel-by-channel relative signal arrival times) for the recorded event.

astro-ph.HE↗