arXiv subjects

K. McBride

Publications and source records attributed to K. McBride.

9 recordsLinked to original sources

arXiv2026

The High-Energy Light Isotope eXperiment (HELIX) Instrument

The HELIX detector is a balloon-borne instrument designed to measure the flux of light (Z < 11) cosmic-ray isotopes. In this paper we describe the initial configuration of HELIX, optimized for measurements in the energy range from approximately 0.2 GeV per nucleon to beyond 3 GeV per nucleon. In addition to a spectrometer, which is based on a one-tesla superconducting magnet and a drift-chamber tracker, HELIX employs scintillator-based time-of-flight counters and a ring-imaging Cherenkov detector, allowing event-by-event reconstruction of primary particle mass, charge, and magnetic rigidity.

astro-ph.IM↗

arXiv2026

Trigger system for the Payload for Ultrahigh Energy Observations (PUEO) balloon-borne neutrino detector

The Payload for Ultrahigh Energy Observations (PUEO) is a NASA balloon-borne instrument for the detection of ultra-high energy (UHE) neutrinos with energies above $10^{17.5}~\textrm{eV}$ via either the Askaryan effect or geomagnetic emissions from an upward-going air shower. The main instrument trigger system for PUEO is a fully digital supersample rate beamformer based on 24 Xilinx Radio Frequency System-on-a-Chip (RFSoC) digitizers sampling 192 channels operating at $3~\textrm{GSa/s}$ and a system clock frequency of $375~\textrm{MHz}$. The trigger implements frequency band conditioning, dynamic radio-frequency interference (RFI) rejection, and matched filtering, with significant emphasis on optimization to reduce both the power and resource usage while maintaining sensitivity. The system implements 48 total synthetic antenna beams with up to 8 antennas each, covering a $\sim25^\circ$ range in zenith and $\sim60^\circ$ range in azimuth. Preflight testing demonstrated a trigger performance of a minimum signal-to-noise ratio (SNR) of $\sim1.5$ using simulated signals while consuming between $5-7~\textrm{W}$ in the trigger logic.

astro-ph.IM↗

arXiv2025

Cosmic Rays and the Askaryan Effect Reveal Subsurface Structure and Buried Ice on the Moon

We present the first full-wavelength numerical simulations of the electric field generated by cosmic ray impacts into the Moon. Billions of cosmic rays fall onto the Moon every year. Ultra-high energy cosmic ray impacts produce secondary particle cascades within the regolith and subsequent coherent, widebandwidth, linearly-polarized radio pulses by the Askaryan Effect. Observations of the cosmic ray particle shower radio emissions can reveal subsurface structure on the Moon and enable the broad and deep prospecting necessary to confirm or refute the existence of polar ice deposits. Our simulations show that the radio emissions and reflections could reveal ice layers as thin as 10 cm and buried under regolith as deep as 9 m. The Askaryan Effect presents a novel and untapped opportunity for characterizing buried lunar ice at unprecedented depths and spatial scales.

physics.space-ph↗

arXiv2023

The High Energy Light Isotope eXperiment program of direct cosmic-ray studies

HELIX is a new NASA-sponsored instrument aimed at measuring the spectra and composition of light cosmic-ray isotopes from hydrogen to neon nuclei, in particular the clock isotopes 10Be (radioactive, with 1.4 Myr lifetime) and 9Be (stable). The latter are unique markers of the production and Galactic propagation of secondary cosmic-ray nuclei, and are needed to resolve such important mysteries as the proportion of secondary positrons in the excess of antimatter observed by the AMS-02 experiment. By using a combination of a 1 T superconducting magnet spectrometer (with drift-chamber tracker) with a high-resolution time-of-flight detector system and ring-imaging Cherenkov detector, mass-resolved isotope measurements of light cosmic-ray nuclei will be possible up to 3 GeV/n in a first stratospheric balloon flight from Kiruna, Sweden to northern Canada, anticipated to take place in early summer 2024. An eventual longer Antarctic balloon flight of HELIX will yield measurements up to 10 GeV/n, sampling production from a larger volume of the Galaxy extending into the halo. We review the instrument design, testing, status and scientific prospects.

astro-ph.IM↗

arXiv2023

Electron-beam Calibration of Aerogel Tiles for the HELIX RICH Detector

The HELIX cosmic-ray detector is a balloon-borne instrument designed to measure the flux of light isotopes in the energy range from 0.2 GeV/n to beyond 3 GeV/n. It will rely on a ring-imaging Cherenkov (RICH) detector for particle identification at energies greater than 1 GeV/n and will use aerogel tiles with refractive index near 1.15 as the radiator. To achieve the performance goals of the experiment it is necessary to know the refractive index and its position dependence over the lateral extent of the tiles to a precision of O(10$^{-4}). In this paper we describe the apparatus and methods developed to calibrate the HELIX tiles in an electron beam, in order to meet this requirement.

astro-ph.IM↗

arXiv2021

Analysis of a Tau Neutrino Origin for the Near-Horizon Air Shower Events Observed by the Fourth Flight of the Antarctic Impulsive Transient Antenna (ANITA)

We study in detail the sensitivity of the Antarctic Impulsive Transient Antenna (ANITA) to possible $ν_τ$ point source fluxes detected via $τ$-lepton-induced air showers. This investigation is framed around the observation of four upward-going extensive air shower events very close to the horizon seen in ANITA-IV. We find that these four upgoing events are not observationally inconsistent with $τ$-induced EASs from Earth-skimming $ν_τ$, both in their spectral properties as well as in their observed locations on the sky. These four events, as well as the overall diffuse and point source exposure to Earth-skimming $ν_τ$, are also compared against published ultrahigh-energy neutrino limits from the Pierre Auger Observatory. While none of these four events occurred at sky locations simultaneously visible by Auger, the implied fluence necessary for ANITA to observe these events is in strong tension with limits set by Auger across a wide range of energies and is additionally in tension with ANITA's Askaryan in-ice neutrino channel above $10^{19}$ eV. We conclude by discussing some of the technical challenges with simulating and analyzing these near horizon events and the potential for future observatories to observe similar events.

astro-ph.HE↗

arXiv2021

A search for ultrahigh-energy neutrinos associated with astrophysical sources using the third flight of ANITA

The ANtarctic Impulsive Transient Antenna (ANITA) long-duration balloon experiment is sensitive to interactions of ultra high-energy (E > 10^{18} eV) neutrinos in the Antarctic ice sheet. The third flight of ANITA, lasting 22 days, began in December 2014. We develop a methodology to search for energetic neutrinos spatially and temporally coincident with potential source classes in ANITA data. This methodology is applied to several source classes: the TXS 0506+056 blazar and NGC 1068, the first potential TeV neutrino sources identified by IceCube, flaring high-energy blazars reported by the Fermi All-Sky Variability Analysis, gamma-ray bursts, and supernovae. Among searches within the five source classes, one candidate was identified as associated with SN 2015D, although not at a statistically significant level. We proceed to place upper limits on the source classes. We further comment on potential applications of this methodology to more sensitive future instruments.

astro-ph.HE↗

arXiv2020

Unusual Near-horizon Cosmic-ray-like Events Observed by ANITA-IV

ANITA's fourth long-duration balloon flight in late 2016 detected 29 cosmic-ray (CR)-like events on a background of $0.37^{+0.27}_{-0.17}$ anthropogenic events. CRs are mainly seen in reflection off the Antarctic ice sheets, creating a characteristic phase-inverted waveform polarity. However, four of the below-horizon CR-like events show anomalous non-inverted polarity, a $p = 5.3 \times 10^{-4}$ chance if due to background. All anomalous events are from locations near the horizon; ANITA-IV observed no steeply-upcoming anomalous events similar to the two such events seen in prior flights.

astro-ph.HE↗

arXiv2019

The Simulation of the Sensitivity of the Antarctic Impulsive Transient Antenna (ANITA) to Askaryan Radiation from Cosmogenic Neutrinos Interacting in the Antarctic Ice

A Monte Carlo simulation program for the radio detection of Ultra High Energy (UHE) neutrino interactions in the Antarctic ice as viewed by the Antarctic Impulsive Transient Antenna (ANITA) is described in this article. The program, icemc, provides an input spectrum of UHE neutrinos, the parametrization of the Askaryan radiation generated by their interaction in the ice, and the propagation of the radiation through ice and air to a simulated model of the third and fourth ANITA flights. This paper provides an overview of the icemc simulation, descriptions of the physics models used and of the ANITA electronics processing chain, data/simulation comparisons to validate the predicted performance, and a summary of the impact of published results.

astro-ph.IM↗