20 research outputs found
Upgrade and Re-Deployment of the Telescope Array RADAR (TARA) Cosmic Ray Observatory Remote Stations
The Telescope Array RADAR experiment is a bi-static radar search for Ultra-High-Energy Cosmic Rays (UHECR). Here we describe an upgrade and re-deployment of two of our detectors, which, owing to their isolation from the main detector apparatus on Long Ridge, Millard County, UT, are called the Remote Stations (RS). The upgrade described here comprises a total overhaul of the trigger and timing systems, with improvements in signal-to-noise ratio sensitivity of approximately 30 dB. Our new firmware-based trigger method is sensitive to expected signals at SNR of -4 dB at high efficiency. Bench-top tests indicate that this new system is sensitive to a Radar Cross Section (RCS) of order one square meter. Deployment of the overhauled stations took place in February 2016, with a planned data-taking duration of 3-6 weeks
Radar detection of cosmic-ray and neutrino induced cascades
An ultra high energy particle, incident upon the earth, will produce a cascade of particles upon interaction. Detection of this cascade holds the key to understanding the properties of the primary-what it was, how much energy it carried, and maybe even where it came from. Of the many strategies developed over the course of the last century to detect such cascades, the radar technique is one of the latest to be explored with interest. For high enough incident energies, the relativistic progression of the cascade through a medium will produce a cloud of ionization that may become dense enough to reflect incident radio-frequency (RF) fields. If so, a broadcasting transmitter and distant receiver could feasibly detect cascades at very long baselines, thereby converting a massive volume of air or ice or sand or salt into a sensitive detector. Such an increase in volume opens up possibility of detecting events which occur on the order of 1km −2 yr −1 or less. In this dissertation, we present a detailed discussion of the radar detection method, focusing specifically on the detection of ultra high energy cosmic rays in the atmosphere, and ultra high energy neutrinos in dense material, such as ice. We will present the history and experimental efforts to date, and include the latest results from recent models and experiments seeking to address the radar problem. Ultimately, we suggest that the radar method is a promising one for the detection of 10 15 eV neutrinos which have interacted in a dense medium, such as the Antarctic ice
New Constraints on Macroscopic Dark Matter Using Radar Meteor Detectors
We show that dark-matter candidates with large masses and large nuclear
interaction cross sections are detectable with terrestrial radar systems. We
develop our results in close comparison to successful radar searches for tiny
meteoroids, aggregates of ordinary matter. The path of a meteoroid (or suitable
dark-matter particle) through the atmosphere produces ionization deposits that
reflect incident radio waves. We calculate the equivalent radar echoing area or
`radar cross section' for dark matter. By comparing the expected number of
dark-matter-induced echoes with observations, we set new limits in the plane of
dark-matter mass and cross section, complementary to pre-existing cosmological
limits. Our results are valuable because (A) they open a new detection
technique for which the reach can be greatly improved and (B) in case of a
detection, the radar technique provides differential sensitivity to the mass
and cross section, unlike cosmological probes.Comment: Main text 14 pages and 11 figures, Appendix 2 pages and 3 figure
SiPM-based azimuthal position sensor in ANITA-IV Hi-Cal Antarctic balloon experiment
Hi-Cal (High-Altitude Calibration) is a balloon-borne experiment that will be launched in December, 2016 in Antarctica following ANITA-IV (Antarctic Impulsive Transient Antenna) and will generate a broad-band pulse over the frequency range expected from radiation induced by a cosmic ray shower. Here, we describe a device based on an array of silicon photomultipliers (SiPMs) for determination of the azimuthal position of Hi-Cal. The angular resolution of the device is about 3 degrees. Since at the float altitude of ~38 km the pressure will be ~0.5 mbar and temperature ~ − 20 °C, the equipment has been tested in a chamber over a range of corresponding pressures (0.5 ÷ 1000) mbar and temperatures (−40 ÷ +50) °C
Prospects for High-Elevation Radio Detection of >100 PeV Tau Neutrinos
Tau neutrinos are expected to comprise roughly one third of both the
astrophysical and cosmogenic neutrino flux, but currently the flavor ratio is
poorly constrained and the expected flux at energies above eV is low.
We present a detector concept aimed at measuring the diffuse flux of tau
neutrinos in this energy range via a high-elevation mountaintop detector using
the radio technique. The detector searches for radio signals from upgoing air
showers generated by Earth-skimming tau neutrinos. Signals from several
antennas in a compact array are coherently summed at the trigger level,
permitting not only directional masking of anthropogenic backgrounds, but also
a low trigger threshold. This design takes advantage of both the large viewing
area available at high-elevation sites and the nearly full duty cycle available
to radio instruments. We present trade studies that consider the station
elevation, frequency band, number of antennas in the array, and the trigger
threshold to develop a highly efficient station design. Such a mountaintop
detector can achieve a factor of ten improvement in acceptance over existing
instruments with 100 independent stations. With 1000 stations and three years
of observation, it can achieve a sensitivity to an integrated
flux of GeV cm sr s, in the
range of the expected flux of all-flavor cosmogenic neutrinos assuming a pure
iron cosmic-ray composition.Comment: 26 pages, 11 figure
Application of parabolic equation methods to in-ice radio wave propagation for ultra high energy neutrino detection experiments
Many ultra-high-energy neutrino-detection experiments seek radio wave signals from neutrino interactions deep within the polar ice, and an understanding of in-ice radio wave propagation is therefore of critical importance. The parabolic equation (PE) method for modeling the propagation of radio waves is a suitable intermediate between ray tracing and finite-difference time domain (FDTD) methods in terms of accuracy and computation time. The RET collaboration has developed the first modification of the PE method for use in modeling in-ice radio wave propagation for ultra high energy cosmic ray and neutrino detection experiments. In this proceeding we will detail the motivation for the development of this technique, the process by which it was modified for in-ice use, and showcase the accuracy of its results by comparing to FDTD and ray tracing.SCOPUS: cp.pinfo:eu-repo/semantics/publishe
Detector Requirements for Model-Independent Measurements of Ultrahigh Energy Neutrino Cross Sections
The ultrahigh energy range of neutrino physics (above ), as yet devoid of detections, is an open landscape with
challenges to be met and discoveries to be made. Neutrino-nucleon cross
sections in that range - with center-of-momentum energies - are powerful probes of unexplored phenomena. We present a
simple and accurate model-independent framework to evaluate how well these
cross sections can be measured for an unknown flux and generic detectors. We
also demonstrate how to characterize and compare detector sensitivity. We show
that cross sections can be measured to % precision over
4-140 TeV (- GeV) with modest energy
and angular resolution and events per energy decade. Many allowed
novel-physics models (extra dimensions, leptoquarks, etc.) produce much larger
effects. In the distant future, with events at the highest
energies, the precision would be , probing even QCD saturation
effects.Comment: 8 pages + Appendices. v2: minor changes, matches published versio
Suggestion of coherent radio reflections from an electron-beam induced particle cascade
Testbeam experiment 576 at the SLAC National Accelerator Laboratory sought to make the first measurement of coherent radio reflections from the ionization produced in the wake of a high-energy particle shower. The >10 GeV electron beam at the SLAC End Station A was directed into a large high-density polyethylene target to produce a shower analogous to that produced by an EeV neutrino interaction in ice. Continuous wave radio was transmitted into the target, and receiving antennas monitored for reflection of the transmitted signal from the ionization left in the wake of the shower. We detail the first run of the experiment and report on preliminary hints of a signal consistent with a radio reflection at a statistical significance of 2.36σ.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Probing the radar scattering cross-section for high-energy particle cascades in ice
Recently the radar scattering technique to probe neutrino induced particle cascades above PeV energies in ice was investigated. The feasibility of the radar detection method was shown to crucially depend on several up to now unknown plasma properties, such as the plasma lifetime and the free charge collision rate. To determine these parameters, a radar scattering experiment was performed at the Telescope Array Electron Light Source facility, where a beam of high-energy electrons was directed in a block of ice. The induced ionization plasma was consequently probed using a radar detection set-up detecting over a wide frequency range from 200 MHz up to 2 GHz. First qualitative results of this experiment will be presented.SCOPUS: cp.pSCOPUS: cp.pinfo:eu-repo/semantics/publishe