Guard rings investigation of silicon sensors with modified pixel implant shapes in the context of the ATLAS experiment

Based on the standard design of the planar n + -in-n silicon pixel sensors of the innermost part of the tracking detector of the ATLAS experiment, six modified pixel designs were developed in Dortmund in order to increase the average electric field and thus the radiation hardness. The REINER pixel sensors contain these six modified pixel implantation shapes beside structures with the standard pixel design. Each pixel structure is provided by 13 guard rings and can be biased and investigated separately. This thesis aims to deeply investigate the electrical performances of the REINER sensors. The individual pixel designs have been cut from the original full REINER structure for the first time and a study of the single structures has been performed. The obtained results show that the cut sensors are broken and cannot be properly used anymore. These unexpected results that have been obtained hint at the investigation of the multi-guard ring structure of the implants in order to investigate the strength of the electric field at the edge of the sensor. The results show that the guard ring structure of each design properly works when a design is biased and its guard rings voltage measured. However, when the guard rings voltage is logged on another design, different from the biased one, the non-zero measurements proves that the pixel designs truly influence each other due to a non-ideal operation of the guard ring structure

Ricerca di neutrini dal piano galattico con il telescopio ANTARES

In questa tesi si cerca un flusso diffuso di neutrini proveniente dal Piano Galattico. ANTARES, un telescopio di neutrini che si trova nel Mar Mediterraneo, ha un’area di visibilità tale da poter osservare questa parte di cielo, quindi isolare l’emissione di neutrini per trovarne le sorgenti. Si osserva la variazione del numero di neutrini atmosferici ricostruiti sotto l'effetto dello scrambling delle coordinate galattiche, effettuando diversi tagli di selezione sul parametro di energia, per verificare la compatibilità dell'osservazione reale con quella simulata

Five years of Sentinel-5p TROPOMI operational ozone profiling and geophysical validation using ozonesonde and lidar ground-based networks

International audienceThe Sentinel-5 Precursor (S5P) satellite operated by the European Space Agency (ESA) carries the TROPOspheric Monitoring Instrument (TROPOMI) on a Sun-synchronous low-Earth orbit since October 13, 2017. The S5P mission has acquired more than five years of TROPOMI nadir ozone profile data retrieved from the Level-0-to-1B processor version 2.0 and the Level-1B-to-2 Optimal Estimation based processor version 2.4.0. The latter is described in detail in this work, followed by the geophysical validation of the resulting ozone profiles for the period May 2018 to April 2023. Comparison of TROPOMI 5 ozone profile data to co-located ozonesonde and lidar measurements used as references, concludes to a median agreement better than 5 to 10 % in the troposphere. The bias goes up to-15 % in the upper stratosphere (35-45 km) where it can exhibit vertical oscillations. The comparisons show a dispersion of about 30 % in the troposphere and 10 to 20 % in the upper troposphere to lower stratosphere (UTLS) and in the middle stratosphere, which is close to mission requirements. Chi-square tests of the observed differences confirm on average the validity of the ex-ante (prognostic) satellite and ground-based data 10 uncertainty estimates in the middle stratosphere, above about 20 km. Around the tropopause and below, the mean chi-square