A general purpose instrument for imaging of Cherenkov light or fluorescence light emitted by extensive air showers is presented. Its refractive optics allows for a compact and light-weight design ...with a wide field-of-view of 12{\deg}. The optical system features a 0.5 m diameter Fresnel lens and a camera with 61 pixels composed of Winston cones and large-sized 6x6 mm photo sensors. As photo sensors, semi conductor light sensors (SiPMs) are utilized. The camera provides a high photon detection efficiency together with robust operation. The enclosed optics permit operation in regions of harsh environmental conditions. The low price of the telescope allows the production of a large number of telescopes and the application of the instrument in various projects, such as FAMOUS for the Pierre Auger Observatory, HAWC's Eye for HAWC or IceAct for IceCube. In this paper the novel design of this telescope and first measurements are presented.
In the last few years, radio detection of cosmic ray air showers has experienced a true renaissance. In particular, the LOPES project has successfully implemented modern interferometric methods to ...measure radio emission from air showers. LOPES has confirmed that the emission is coherent and of geomagnetic origin, as expected by the geosynchrotron mechanism, and has demonstrated that a large scale application of the radio technique has great potential to complement current measurements of ultra-high energy cosmic rays.
Using data collected by the Askaryan Radio Array (ARA) experiment at the South Pole, we have used long-baseline propagation of radio-frequency signals to extract information on the radio-frequency ...index-of-refraction in South Polar ice. Owing to the increasing ice density over the upper 150--200 meters, rays are observed along two, nearly parallel paths, one of which is direct and a second which refracts through an inflection point, with differences in both arrival time and arrival angle that can be used to constrain the neutrino properties. We also observe indications, for the first time, of radio-frequency ice birefringence for signals propagating along predominantly horizontal trajectories, corresponding to an asymmetry of order 0.1% between the ordinary and extra-ordinary paths, numerically compatible with previous measurements of birefringent asymmetries for vertically-propagating radio-frequency signals at South Pole. Taken together, these effects offer the possibility of redundantly measuring the range from receiver to a neutrino interaction in Antarctic ice, if receiver antennas are deployed at shallow (25 m<z<100 m) depths. Such range information is essential in determining both the neutrino energy, as well as the incident neutrino direction.
Detecting Radio Pulses from Air Showers Horneffer, A.; Apel, W.D.; Arteaga, J.C. ...
2008 IEEE Nuclear Science Symposium Conference Record,
2008-Oct.
Conference Proceeding
Cosmic rays are energetic particles from outside the earth's atmosphere. When a high energy cosmic ray hits the atmosphere it triggers a cascade of secondary particles produced in nuclear ...interactions, an air shower. Up to now the established methods of measuring air showers are detection of the particles that reach the ground level or optical observation of the Cherenkov or fluorescent light.
The Askaryan Radio Array (ARA) reports an observation of radio emission coincident with the "Valentine's Day" solar flare on Feb. 15\(^{\rm{th}}\), 2011 in the prototype "Testbed" station. We find ...\(\sim2000\) events that passed our neutrino search criteria during the 70 minute period of the flare, all of which reconstruct to the location of the sun. A signal analysis of the events reveals them to be consistent with that of bright thermal noise correlated across antennas. This is the first natural source of radio emission reported by ARA that is tightly reconstructable on an event-by-event basis. The observation is also the first for ARA to point radio from individual events to an extraterrestrial source on the sky. We comment on how the solar flares, coupled with improved systematic uncertainties in reconstruction algorithms, could aid in a mapping of any above-ice radio emission, such as that from cosmic-ray air showers, to astronomical locations on the sky.
We report on a search for ultra-high-energy (UHE) neutrinos from gamma-ray bursts (GRBs) in the data set collected by the Testbed station of the Askaryan Radio Array (ARA) in 2011 and 2012. From 57 ...selected GRBs, we observed no events that survive our cuts, which is consistent with 0.12 expected background events. Using NeuCosmA as a numerical GRB reference emission model, we estimate upper limits on the prompt UHE GRB neutrino fluence and quasi-diffuse flux from \(10^{7}\) to \(10^{10}\) GeV. This is the first limit on the prompt UHE GRB neutrino quasi-diffuse flux above \(10^{7}\) GeV.
The Askaryan Radio Array (ARA) is an ultra-high energy (\(>10^{17}\) eV) cosmic neutrino detector in phased construction near the South Pole. ARA searches for radio Cherenkov emission from particle ...cascades induced by neutrino interactions in the ice using radio frequency antennas (\(\sim150-800\) MHz) deployed at a design depth of 200 m in the Antarctic ice. A prototype ARA Testbed station was deployed at \(\sim30\) m depth in the 2010-2011 season and the first three full ARA stations were deployed in the 2011-2012 and 2012-2013 seasons. We present the first neutrino search with ARA using data taken in 2011 and 2012 with the ARA Testbed and the resulting constraints on the neutrino flux from \(10^{17}-10^{21}\) eV.
We report on a measurement of the cosmic ray energy spectrum with the IceTop air shower array, thesurface component of the IceCube Neutrino Observatory at the South Pole. The data used in this ...analysiswere taken between June and October, 2007, with 26 surface stations operational at that time, corresponding to about one third of the final array. The fiducial area used in this analysis was 0.122 square kilometers.The analysis investigated the energy spectrum from 1 to 100 PeV measured for three different zenithangle ranges between 0 and 46. Because of the isotropy of cosmic rays in this energy range the spectrafrom all zenith angle intervals have to agree. The cosmic-ray energy spectrum was determined under differentassumptions on the primary mass composition. Good agreement of spectra in the three zenithangle ranges was found for the assumption of pure proton and a simple two-component model. Forzenith angles theta less than 30 deg., where the mass dependence is smallest, the knee in the cosmic ray energy spectrumwas observed at about 4 PeV, with a spectral index above the knee of about -3.1. Moreover, an indicationof a flattening of the spectrum above 22 PeV was observed.
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