Development of a sub-glacial array of radio antennas for the detection of the flux of GZK neutrinos

GZK neutrino are interesting messenger particles since, if detected, they can transmit<p>us exclusive information about ultra-high energy processes in the Universe. These particles,<p>which hold energies above 10^16 eV, interact very rarely. Therefore, detectors of<p>several gigatons of matter are needed to discover them. The ARA detector is planned<p>and currently being constructed at the South Pole. It is designed to use the Askaryan<p>effect, the emission of radio waves from neutrino induced cascades in the South Pole ice,<p>to detect neutrino interactions. With antennas distributed in 37 stations in the ice, such<p>interactions can be observed in a volume of several hundred cubic kilometers. Currently<p>2 ARA stations have been deployed in the ice and are taking data since the beginning<p>of the year 2013.<p>The first part of this thesis summarizes the current theories concerning the GZK mechanism<p>and the Askaryan effect to explain the interest in GZK neutrinos and in the used<p>detection method.<p>In the second part the ARA detector is described and calibrations of different detector<p>parts are presented. In this work, the digitization chips have been calibrated concerning<p>their timing precision and signal amplitude. In this way a timing precision of 100 ps<p>between antennas could be achieved. Furthermore, the geometry of the antenna clusters<p>is determined by cuts based on external signals to allow for a proper radio vertex reconstruction.<p>In the third part of the thesis the development of methods to distinguish radio signals<p>from thermal noise are presented. Moreover, a reconstruction method, developed to determine<p>the position of radio sources, is described. With only two stations operational<p>a discovery of GZK neutrinos is not expected and in fact no signal candidate has been<p>found in the analysis of the data. A neutrino <p>ux limit is calculated. This limit is not<p>competitive yet with the current best limits, but very promising for the full ARA detector.<p>The work shows that after completion this detector is expected to be capable of a<p>neutrino discovery.Doctorat en Sciences