Are you an EPFL student looking for a semester project?
Work with us on data science and visualisation projects, and deploy your project as an app on top of Graph Search.
Since almost a century ago, it is known that a quarter of the energy density in the Universe is represented by the dark matter which has been seen only through gravitational interaction. Despite of intensive searches for a dark matter constituent in different methods, no positive results have been seen yet. Recently, special hopes are put into the observation of the charged cosmic rays which could bear signs of dark matter annihilation. This is due to the several anomalies observed in positron fraction and total e+ +e− flux in the cosmic rays. Since the available data do not allow to draw strong conclusion about the nature of those anomalies, a new balloon-borne experiment for the precise measurement of the cosmic ray positron fraction has been proposed. A Positron Electron Balloon Spectrometer (PEBS) is equipped with a magnetic spectrometer, a transition radiation detector, an electromagnetic calorimeter and a time of flight system, and will give the means to extend the measurement to higher energies. This thesis is devoted to the description of the development and performance study of one of the PEBS constituents - the electromagnetic calorimeter (ECAL). This sub-detector plays a key role in the PEBS performance delivering an energy measurement of incident positrons and electrons and allowing to distinguish the positrons from the vast proton background. The ECAL uses a novel approach for the light detection - silicon photomultipliers (SiPM). The understanding of the SiPM response to the large range of signals, starting from tens of photons and going up to tens of thousands of photons, is necessary in calorimetry applications. Therefore a detailed study of their operation is carried out with simulation and described in this work. During the four years of study, two prototypes of the ECAL were built and exposed to a test beam at PS and SPS facilities at CERN. The results of the prototypes performance for the energies up to 180 GeV are discussed in detail, assessing the PEBS ECAL capabilities to achieve design requirements for particle identification.
Jian Wang, Matthias Finger, Qian Wang, Yiming Li, Matthias Wolf, Varun Sharma, Yi Zhang, Konstantin Androsov, Jan Steggemann, Leonardo Cristella, Xin Chen, Davide Di Croce, Arvind Shah, Rakesh Chawla, João Miguel das Neves Duarte, Tagir Aushev, Tian Cheng, Yixing Chen, Werner Lustermann, Andromachi Tsirou, Alexis Kalogeropoulos, Andrea Rizzi, Ioannis Papadopoulos, Paolo Ronchese, Hua Zhang, Siyuan Wang, Jessica Prisciandaro, Peter Hansen, Tao Huang, David Vannerom, Michele Bianco, Sebastiana Gianì, Kun Shi, Wei Shi, Abhisek Datta, Wei Sun, Jian Zhao, Thomas Berger, Federica Legger, Bandeep Singh, Ji Hyun Kim, Donghyun Kim, Dipanwita Dutta, Zheng Wang, Sanjeev Kumar, Wei Li, Yong Yang, Geng Chen, Yi Wang, Ajay Kumar, Ashish Sharma, Georgios Anagnostou, Joao Varela, Csaba Hajdu, Muhammad Ahmad, Ekaterina Kuznetsova, Ioannis Evangelou, Matthias Weber, Muhammad Shoaib, Milos Dordevic, Vineet Kumar, Francesco Fiori, Quentin Python, Meng Xiao, Sourav Sen, Viktor Khristenko, Xiao Wang, Kai Yi, Jing Li, Rajat Gupta, Zhen Liu, Muhammad Waqas, Hui Wang, Seungkyu Ha, Maren Tabea Meinhard, Giorgia Rauco, Ali Harb, Benjamin William Allen, Long Wang, Pratyush Das, Miao Hu, Anton Petrov, Xin Gao, Chen Chen, Valérie Scheurer, Giovanni Mocellin, Muhammad Ansar Iqbal, Lukas Layer
Jian Wang, Matthias Finger, Qian Wang, Yiming Li, Matthias Wolf, Varun Sharma, Yi Zhang, Konstantin Androsov, Jan Steggemann, Xin Chen, Rakesh Chawla, Matteo Galli, Anna Mascellani, João Miguel das Neves Duarte, Tagir Aushev, Tian Cheng, Yixing Chen, Werner Lustermann, Andromachi Tsirou, Alexis Kalogeropoulos, Andrea Rizzi, Ioannis Papadopoulos, Paolo Ronchese, Hua Zhang, Siyuan Wang, Tao Huang, David Vannerom, Michele Bianco, Sebastiana Gianì, Sun Hee Kim, Kun Shi, Abhisek Datta, Federica Legger, Gabriele Grosso, Ji Hyun Kim, Donghyun Kim, Zheng Wang, Sanjeev Kumar, Wei Li, Yong Yang, Geng Chen, Ajay Kumar, Ashish Sharma, Georgios Anagnostou, Joao Varela, Csaba Hajdu, Muhammad Ahmad, Ioannis Evangelou, Milos Dordevic, Meng Xiao, Sourav Sen, Xiao Wang, Kai Yi, Jing Li, Rajat Gupta, Hui Wang, Seungkyu Ha, Long Wang, Pratyush Das, Anton Petrov, Xin Sun, Xin Gao, Valérie Scheurer, Giovanni Mocellin, Muhammad Ansar Iqbal, Lukas Layer