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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

HitSpooling: an improvement for the supernova neutrino detection system in icecube

Heereman von Zuydtwyck, David 13 July 2015 (has links)
The IceCube Neutrino Observatory consists of a lattice of 5160 photomultiplier tubes (PMTs)<p>which monitor one cubic kilometer of deep Antarctic ice at the geographic South Pole.<p>IceCube was primarily designed to detect neutrinos of energies greater than O(100 GeV).<p>Due to subfreezing ice temperatures, the photomultipliers' dark noise rates are particularly<p>low which enables IceCube to search for neutrinos from galactic supernovae by detecting<p>bursts of MeV neutrinos emitted during the core collapse and for several seconds following.<p>For that purpose, a dedicated online supernova DAQ system records the total number of hits<p>in the detector, without any further information from the PMTs, and generates supernova<p>candidate triggers in case of a significant detector rate enhancement. A new feature to the<p>standard DAQ, called HitSpooling, was implemented in IceCube during this thesis. The<p>HitSpooling system is implemented in the standard DAQ system and buffers the complete<p>raw data stream of the photomultipliers for several hours or days. By reading out time periods<p>of HitSpool data around supernova candidate triggers, generated by the online supernova<p>DAQ system, we overcome the limitations of the latter and have access to the entire information<p>of the detector in case of a supernova. Furthermore, HitSpool data is a powerful<p>source for studying and understanding the noise behavior of the detector as well as background<p>processes coming from atmospheric muons. The idea of HitSpooling was developed in the<p>scope of this thesis and is the basis of the work at hand. The developed interface between the<p>standard DAQ and the supernova DAQ system is presented. The correlated dark noise component<p>in optical modules of IceCube is quantified for the first time and possible explanations<p>are discussed. The possibility of identifying triggering and subthreshold atmospheric muons<p>in HitSpool data and subtracting them from a possible supernova signal is analyzed. Furthermore,<p>the conversion from HitSpool data to supernova DAQ type data was developed<p>which allows for a comparison of both data types with respect to lightcurves and significances<p>of selected supernova candidate triggers. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

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