36 research outputs found
Calibration and Physics with ARA Station 1: A Unique Askaryan Radio Array Detector
The Askaryan Radio Array Station 1 (A1), the first among five autonomous
stations deployed for the ARA experiment at the South Pole, is a unique
ultra-high energy neutrino (UHEN) detector based on the Askaryan effect that
uses Antarctic ice as the detector medium. Its 16 radio antennas (distributed
across 4 strings, each with 2 Vertically Polarized (VPol), 2 Horizontally
Polarized (HPol) receivers), and 2 strings of transmitting antennas
(calibration pulsers, CPs), each with 1 VPol and 1 HPol channel, are deployed
at depths less than 100 m within the shallow firn zone of the 2.8 km thick
South Pole (SP) ice. We apply different methods to calibrate its Ice Ray
Sampler second generation (IRS2) chip for timing offset and ADC-to-Voltage
conversion factors using a known continuous wave input signal to the digitizer,
and achieve a precision of sub-nanoseconds. We achieve better calibration for
odd, compared to even samples, and also find that the HPols under-perform
relative to the VPol channels. Our timing calibrated data is subsequently used
to calibrate the ADC-to-Voltage conversion as well as precise antenna
locations, as a precursor to vertex reconstruction. The calibrated data will
then be analyzed for UHEN signals in the final step of data compression. The
ability of A1 to scan the firn region of SP ice sheet will contribute greatly
towards a 5-station analysis and will inform the design of the planned IceCube
Gen-2 radio array.Comment: 10 page
Preliminary Investigation of the Corrosion Behavior of Proprietary Micro-alloyed Steels in Aerated and Deaerated Brine Solutions
The corrosion performance of fairly new generation of micro-alloyed steels was compared in different concentrations of aerated and deaerated brines. Electrochemical polarization, weight loss and surface analyses techniques were employed. The results showed a threshold of corrosion rate at 3.5 wt.% NaCl in both aerated and deaerated solutions. The average corrosion current density for steel B, for example, increased from 1.3 µA cm¯² in 1 wt.% NaCl to 1.5 µA cm¯² in 3.5 wt.% NaCl, but decreased to 1.4 µA cm¯² in 10 wt.% deaerated NaCl solutions. The aerated solutions exhibited an average of over 80% increase in corrosion current density in the respective concentrations when compared with the deaerated solution. These results can be attributed to the effects of dissolved oxygen (DO) which has a maximum solubility in 3.5 wt.% NaCl. DO as a depolarizer and electron acceptor in cathodic reactions accelerates anodic metal dissolution. The difference in carbon content and microstructures occasioned by thermo-mechanical treatment contributed to the witnessed variation in corrosion performance of the steels. Specifically, the results of the various corrosion techniques corroborated each other and showed that the corrosion rate of the micro-alloyed steels can be ranked as CR[Steel A] < CRₓ₆₅ < CR[Steel B] < CR[Steel C]
MARES: A macroscopic approach to the radar echo scatter from high-energy particle cascades
In this work, we provide a macroscopic model to predict the radar echo
signatures found when a radio signal is reflected from a cosmic-ray or
neutrino-induced particle cascade propagating in a dense medium like ice. Its
macroscopic nature allows for an energy independent runtime, taking less than
10 s for simulating a single scatter event. As a first application, we discuss
basic signal properties and simulate the expected signal for the T-576
beam-test experiment at the Stanford Linear Accelerator Center (SLAC). We find
good signal strength agreement with the only observed radar echo from a
high-energy particle cascade to date.Comment: To be submitte
Precision measurement of the index of refraction of deep glacial ice at radio frequencies at Summit Station, Greenland
Glacial ice is used as a target material for the detection of ultra-high
energy neutrinos, by measuring the radio signals that are emitted when those
neutrinos interact in the ice. Thanks to the large attenuation length at radio
frequencies, these signals can be detected over distances of several
kilometers. One experiment taking advantage of this is the Radio Neutrino
Observatory Greenland (RNO-G), currently under construction at Summit Station,
near the apex of the Greenland ice sheet. These experiments require a thorough
understanding of the dielectric properties of ice at radio frequencies. Towards
this goal, calibration campaigns have been undertaken at Summit, during which
we recorded radio reflections off internal layers in the ice sheet. Using data
from the nearby GISP2 and GRIP ice cores, we show that these reflectors can be
associated with features in the ice conductivity profiles; we use this
connection to determine the index of refraction of the bulk ice as n=1.778 +/-
0.006
In situ, broadband measurement of the radio frequency attenuation length at Summit Station, Greenland
Over the last 25 years, radiowave detection of neutrino-generated signals,
using cold polar ice as the neutrino target, has emerged as perhaps the most
promising technique for detection of extragalactic ultra-high energy neutrinos
(corresponding to neutrino energies in excess of 0.01 Joules, or
electron volts). During the summer of 2021 and in tandem with the initial
deployment of the Radio Neutrino Observatory in Greenland (RNO-G), we conducted
radioglaciological measurements at Summit Station, Greenland to refine our
understanding of the ice target. We report the result of one such measurement,
the radio-frequency electric field attenuation length . We find an
approximately linear dependence of on frequency with the best fit of
the average field attenuation for the upper 1500 m of ice: MHz m for
frequencies MHz.Comment: 13 pages, 8 figures, Accepted to Journal of Glaciolog
Measurement of atmospheric neutrino mixing with improved IceCube DeepCore calibration and data processing
We describe a new data sample of IceCube DeepCore and report on the latest measurement of atmospheric neutrino oscillations obtained with data recorded between 2011–2019. The sample includes significant improvements in data calibration, detector simulation, and data processing, and the analysis benefits from a sophisticated treatment of systematic uncertainties, with significantly greater level of detail since our last study. By measuring the relative fluxes of neutrino flavors as a function of their reconstructed energies and arrival directions we constrain the atmospheric neutrino mixing parameters to be sin2θ23=0.51±0.05 and Δm232=2.41±0.07×10−3 eV2, assuming a normal mass ordering. The errors include both statistical and systematic uncertainties. The resulting 40% reduction in the error of both parameters with respect to our previous result makes this the most precise measurement of oscillation parameters using atmospheric neutrinos. Our results are also compatible and complementary to those obtained using neutrino beams from accelerators, which are obtained at lower neutrino energies and are subject to different sources of uncertainties
Measurement of Atmospheric Neutrino Mixing with Improved IceCube DeepCore Calibration and Data Processing
We describe a new data sample of IceCube DeepCore and report on the latest
measurement of atmospheric neutrino oscillations obtained with data recorded
between 2011-2019. The sample includes significant improvements in data
calibration, detector simulation, and data processing, and the analysis
benefits from a detailed treatment of systematic uncertainties, with
significantly higher level of detail since our last study. By measuring the
relative fluxes of neutrino flavors as a function of their reconstructed
energies and arrival directions we constrain the atmospheric neutrino mixing
parameters to be and , assuming a normal mass ordering. The
resulting 40\% reduction in the error of both parameters with respect to our
previous result makes this the most precise measurement of oscillation
parameters using atmospheric neutrinos. Our results are also compatible and
complementary to those obtained using neutrino beams from accelerators, which
are obtained at lower neutrino energies and are subject to different sources of
uncertainties
Search for Extended Sources of Neutrino Emission in the Galactic Plane with IceCube
The Galactic plane, harboring a diffuse neutrino flux, is a particularly
interesting target to study potential cosmic-ray acceleration sites. Recent
gamma-ray observations by HAWC and LHAASO have presented evidence for multiple
Galactic sources that exhibit a spatially extended morphology and have energy
spectra continuing beyond 100 TeV. A fraction of such emission could be
produced by interactions of accelerated hadronic cosmic rays, resulting in an
excess of high-energy neutrinos clustered near these regions. Using 10 years of
IceCube data comprising track-like events that originate from charged-current
muon neutrino interactions, we perform a dedicated search for extended neutrino
sources in the Galaxy. We find no evidence for time-integrated neutrino
emission from the potential extended sources studied in the Galactic plane. The
most significant location, at 2.6 post-trials, is a 1.7 sized
region coincident with the unidentified TeV gamma-ray source 3HWC J1951+266. We
provide strong constraints on hadronic emission from several regions in the
Galaxy.Comment: 13 pages, 4 figures, 5 tables including an appendix. Accepted for
publication in Astrophysical Journa