Air shower registration algorithm and mathematical processing of showers with radio signal at the Yakutsk array

The paper describes the techniques and method of registration of air shower radio emission at the Yakutsk array of extensive air showers at a frequency of 32 MHz. At this stage, emission registration involves two set of antennas, the distance between them is 500m. One set involves 8 antennas, second - 4 antennas. The antennas are perpendicularly crossed dipoles with radiation pattern North South,West East and raised 1.5 m above the ground. Each set of antennas connected to an industrial PC. The registration requires one of two triggers. First trigger are generated by scintillation detectors of Yakutsk array. Scintillation detectors cover area of 12 km^2 and registers air showers with energy more than 10^17 eV. The second trigger is generated by Small Cherenkov Array that covers area of 1 km^2 and registers air showers with energy 10^15 - 5*10^17 eV. Small Cherenkov Array is part of Yakutsk array and involve Cherenkov detectors located at a distance of 50, 100, 250 m. For further selection we are using an additional criterion the radio pulse must be localized in the area corresponding to the delay time on first and second triggers. In addition, descriptions of the algorithm and the flowcharts of the program for the air shower selection and further analysis are given. This method registers EAS radio emission with energy 10^16 - 10^19 eV. With the absolute calibration, the amplitudes of all antennas converted to a single value. Air shower radio emission dependences from zenith angle and shower energy are plotted.

Yakutsk array radio emission registration results in the energy range of 3*10^16-5*10^18 eV

This paper presents the set of measurements of ultra-high energy air shower radio emission at frequency 32 MHz in period of 2008-2012. The showers are selected by geomagnetic and azimuth angles and then by the energy in three intervals: 3*10^16 3*10^17 eV, 3*10^17 6*10^17 eV and 6*10^17 5*10^18 eV. In each energy interval average lateral distribution function using mathematically averaged data from antennas with different directions are plotted. In the paper, using experimental data the dependence of radio signal averaged amplitude from geomagnetic angle, the shower axis distance and the energy are determined. Depth of maximum of cosmic ray showers Xmax for the given energy range is evaluated. The evaluation is made according QGSJET model calculations and average lateral distribution function shape.