A5078043712- Astrophysics and Cosmic Phenomena
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Particle physics theoretical and experimental studies
- Gamma-ray bursts and supernovae
- Pulsars and Gravitational Waves Research
- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Radio Wave Propagation Studies
- Particle accelerators and beam dynamics
- Computational Physics and Python Applications
- Particle Detector Development and Performance
- Gyrotron and Vacuum Electronics Research
- Radiation Detection and Scintillator Technologies
- Cryospheric studies and observations
- Atmospheric Ozone and Climate
- Radiation Therapy and Dosimetry
- Arctic and Antarctic ice dynamics
- Geophysics and Gravity Measurements
- Scientific Research and Discoveries
- Precipitation Measurement and Analysis
- Atomic and Subatomic Physics Research
- Noncommutative and Quantum Gravity Theories
- Radio, Podcasts, and Digital Media
University of Wisconsin–River Falls
2016-2025
The University of Texas at Arlington
2018-2024
Lawrence Berkeley National Laboratory
2023-2024
Southern University and Agricultural and Mechanical College
2013-2024
Clark Atlanta University
2013-2024
University of Alaska Anchorage
2007-2024
Providence College
2007-2024
UCLouvain
2023
Chiang Mai University
2021-2023
Pacific Northwest National Laboratory
2023
We present new limits on ultrahigh energy neutrino fluxes above ${10}^{17}\text{ }\text{ }\mathrm{eV}$ based data collected by the Radio Ice Cherenkov Experiment (RICE) at South Pole from 1999--2005. discuss estimation of backgrounds, calibration and analysis algorithms (both online offline), procedures used for dedicated search, refinements in our Monte Carlo (MC) simulation, including recent situ measurements complex ice dielectric constant. An enlarged set a more detailed study hadronic...
Radio Cherenkov radiation is arguably the most efficient mechanism for detecting showers from ultrahigh energy particles of 1 PeV and above. Showers occurring in Antarctic ice should be detectable at distances up to km. We report on electromagnetic shower development using a GEANT Monte Carlo simulation. have studied deposition by determined parameters several different media, finding agreement with published results where available. also radio pulse emission charged shower, focusing...
Abstract The energy spectrum of Galactic cosmic-ray (GCR) ions at Earth varies with solar activity as these cross the heliosphere. Thus, this “solar modulation” GCRs provides remote sensing heliospheric conditions throughout ∼11 yr sunspot cycle and ∼22 magnetic cycle. A neutron monitor (NM) is a stable ground-based detector that measures rate variations above geomagnetic or atmospheric cutoff rigidity high precision (∼0.1%) over such timescales. Furthermore, we developed electronics...
A search for muon neutrinos from dark matter annihilations in the Galactic Center region has been performed with 40-string configuration of IceCube Neutrino Observatory using data collected 367 days live-time starting April 2008. The observed fluxes were consistent atmospheric background expectations. Upper limits on self-annihilation cross-section are obtained particle masses ranging 100 GeV to 10 TeV. In case decaying matter, lower lifetime have determined between 200 and 20
We reevaluate our published calculations of electromagnetic showers generated by GEANT 3.21 and the radio frequency pulses they produce in ice. are prompted a recent report showing that 3.21--modeled sensitive to internal settings electron tracking subroutine. shower pulse characteristics obtained with different 4. The default setting we used previous work speeds up simulation at cost information near end tracks. find ${e}^{\ensuremath{-}}$ ${e}^{+}$ lower energy yield more accurate...
Abstract A technique has recently been developed for tracking short-term spectral variations in Galactic cosmic rays (GCRs) using data from a single neutron monitor (NM), by collecting histograms of the time delay between successive counts and extracting leader fraction L as proxy index. Here we analyze four Antarctic NMs 2015 March to 2023 September. We have calibrated South Pole NM with respect daily index determined published GCR proton fluxes during 2015–2019 Alpha Magnetic Spectrometer...
Using a Kolmogorov turbulence model, we investigate the effects of fluctuations in matter and neutrino density region near supernova core on flavor oscillations neutrinos emitted collapse single-angle, two-flavor approximation. Deviation from smooth background causes significant alterations final state ensemble after 400 km, but even very large do not strongly affect collective phase. In both cases, there is strong effect evolution at intermediate radii, with becoming much more chaotic. The...
From histograms of time delays between counts in a neutron monitor, one can extract the leader fraction, $L$, that did not follow previous count same counter tube associated with cosmic ray shower. The fraction is inverse multiplicity and indicate variations spectral index over certain rigidity range above local cutoff. Here we calibrate $L$ from South Pole an atmospheric cutoff $\sim 1$ GV, respect to daily determined using published data Alpha Magnetic Spectrometer (AMS-02) aboard...
A technique has recently been developed for tracking short-term spectral variations in Galactic cosmic rays (GCRs) using data from a single neutron monitor (NM), by collecting histograms of the time delay between successive counts and extracting leader fraction $L$ as proxy index. Here we analyze four Antarctic NMs during 2015 March to 2023 September. We have calibrated South Pole NM with respect daily index determined published GCR proton fluxes 2015--2019 Alpha Magnetic Spectrometer...
Observations of apparent neutron bursts from air shower cores interacting in soil have been recently reported. The primary mechanism for bursts, which show up as anomalous long-duration counts a detector, is the production evaporation neutrons that enter ground vicinity detector. Neutron monitors are ground-based detectors observe cosmic ray flux GeV range, allowing them to be sensitive bursts. would produce an unwanted background should taken into account spectral studies using...
Magnetic activity on the sun influences flux of galactic cosmic rays at Earth in process known as solar modulation. While most pronounced 1 GeV and below, it also operates much higher energy, still exhibiting magnetic polarity dependence. Historically, an observational gap exists between approximately 17 (the highest geomagnetic cutoff) neutron monitor data muon observations primary that are mostly above 50 GeV. We have shown a can be used calorimeter to measure spectrum atmospheric...
Neutron monitors (NM) are ground-based cosmic ray detectors that measure the flux of primary rays at GeV-energy range by counting (primarily) secondary neutrons in atmospheric cascades. The South Pole NM started 1964 as an International Geophysical Year (IGY) monitor operated until 1974. In 1977 three NM64 with boron-trifluoride proportional counters were installed. January 2004, they replaced helium-3 detectors. Apart from a four-year gap (2005-2009), has continuously since then. Over...
Whitepaper #349 in the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033. Main topics: space weather applications; basic research. Additional research/operations/research loop; research/applications/operations pipeline; […]