We study the longitudinal development of hadronic showers in ice for energies up to 100 EeV and its implications for radio and optical Cherenkov emission. A small fraction of showers induced by ...primaries of energy above 1 EeV is shown to display the characteristic elongation associated to the Landau Pomeranchuck Migdal (LPM) effect. The rest look like ordinary showers because the highest energy
π
0's interact instead of decaying in two photons. The LPM effect observed in this fraction of the showers is mainly due to
η and
η′ production and decay. We give parameterizations for the total and excess charge tracklengths and for the amplitude and angular spread of the electric field spectrum in the Cherenkov direction. Implications for neutrino detection are briefly addressed.
In the present work we carry out a study of the high energy cosmic rays mass identification capabilities of a hybrid detector employing both fluorescence telescopes and particle detectors at ground ...using simulated data. It involves the analysis of extensive showers with zenith angles above 60° making use of the joint distribution of the depth of maximum and muon size at ground level as mass discriminating parameters. The correlation and sensitivity to the primary mass are investigated. Two different techniques – clustering algorithms and neural networks – are adopted to classify the mass identity on an event-by-event basis. Typical results for the achieved performance of identification are reported and discussed. The analysis can be extended in a very straightforward way to vertical showers or can be complemented with additional discriminating observables coming from different types of detectors.
This paper presents our results for full 3-D simulations of very-high to ultra-high energy electromagnetic cascades – and the associated coherent Cherenkov radiation – as might be produced by ...high-energy neutrino interactions in dense media. Using “thinning” techniques, we develop an algorithm based on the existing “ZHS” code, and demonstrate that the new “ZHS-thinned” code can produce fast and accurate results for showers up to
10
20
eV
. Using ZHS-thinned, we develop new parameterisations for the radiation from showers in ice, salt, and the lunar regolith, with a separate treatment of the megaregolith (deep regolith). Our parameterisations include for the first time a method to simulate fluctuations in shower length induced by the LPM effect. Our results, which avoid the pit-falls of scaling simulations from lower energies, allow improved calculations of the detection probability for experiments searching for high-energy neutrinos using the radio technique.
We study the implications of the LPM effect for the Cherenkov radiation of EeV electromagnetic showers in the coherent radiowave regime for ice. We show that for showers above 100 PeV the electric ...field scales with shower energy but has a markedly narrower angular distribution than for lower energy showers. We give an electric field frequency and angular spectrum parameterization valid for showers having energy up to the EeV regime and discuss the implications for neutrino detectors based on arrays of radio antennas. Implications of the LPM effect for under water neutrino detectors in project are also briefly addressed.
We present the design, implementation and data taking performance of the MIcrowave Detection of Air Showers (MIDAS) experiment, a large field of view imaging telescope designed to detect microwave ...radiation from extensive air showers induced by ultra-high energy cosmic rays. This novel technique may bring a tenfold increase in detector duty cycle when compared to the standard fluorescence technique based on detection of ultraviolet photons. The MIDAS telescope consists of a 4.5m diameter dish with a 53-pixel receiver camera, instrumented with feed horns operating in the commercial extended C-Band (3.4–4.2GHz). A self-trigger capability is implemented in the digital electronics. The main objectives of this first prototype of the MIDAS telescope – to validate the telescope design, and to demonstrate a large detector duty cycle – were successfully accomplished in a dedicated data taking run at the University of Chicago campus prior to installation at the Pierre Auger Observatory.
•The MIDAS objective is to detect ultra high energy cosmic rays using microwaves.•GHz radiation could provide a powerful alternative to current detection methods.•The MIDAS prototype explores the potential of the microwave technique.
Inclined air showers – those arriving at ground with zenith angle with respect to the vertical
θ
>
60
°
– are characterised by the dominance of the muonic component at ground which is accompanied by ...an electromagnetic “halo” produced mainly by muon decay and muon interactions. By means of Monte Carlo simulations we give a full characterisation of the particle densities at ground in ultra-high energy inclined showers as a function of primary energy and mass composition, as well as for different hadronic models assumed in the simulations. We also investigate the effect of intrinsic shower-to-shower fluctuations in the particle densities.
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