Browsing by Author "Gezhagn, Tewodros"

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    Electromagnetic Fields in Relativistic Heavy Ion Collisions
    (Addis Ababa University, 2021-03-25) Gezhagn, Tewodros
    Understanding the Quark Gluon Plasma, whose existence was known from the combination of three observations; is the central goal of high energy physics. All the three observations came from studying elliptic ow: how the energy; momentum and number of created particles are not uniform with direction. Any elliptic ow related studies have the chance to clear the road of understanding QGP well and answering what a_ects elliptic ow is part of the journey. This includes quantifying the created electromagnetic _eld during heavy ion collisions; which is ignored by the hydrodynamic models; and investigating its contribution to the ow of particles. So; the purpose of this research was to investigate the e_ect of electromagnetic _eld evolution created in relativistic heavy ion collision on the ow of identi_ed particles. In order to address these problems; our model set-up followed three basic steps: describe the full relativistic viscous hydrodynamics of the considered heavy ions collision using the well known iEBE􀀀VISHNU frame work; calculate the electromagnetic _eld created by the system with the possible drifting velocity sparked by it and _nally investigate the change it brought to the _nal ow of those particles after injecting the drift velocities. The evolution of the electromagnetic _elds calculated was found to play a role on the bending of ow. Beside the nature of created particles; the _eld evolution was a_ected by the electrical conductivity of the evolved system. The _eld arouse ow at lower transverse momentum and suppress it at higher. This change in ow is larger for heavier particles than the lighter ones during the early evolution time. Finally we found that; even ow harmonics are a_ected than the odds. This study de_nitively answers the question on whether elliptic ow is a_ected by the evolved electromagnetic _eld or not. Further study by softening many of the crude assumptions we made and a full event by event viscous hydrodynamic simulation, keeping the functionality of parameters we took as constant, is needed to establish a better ground on understanding the e_ect of electromagnetic _eld well and see from there what new things we can learn about the QGP.
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    Estimation of Amount of Sodium in the Natural Rock Sample using Neutron Activation Analysis
    (Addis Ababa University, 2012-03) Gezhagn, Tewodros
    This study deals with the elemental analysis of rock sample which are collected from North Wollo (Woldia). Neutron Activation Analysis (NAA) is a sensitive analytical technique useful for performing both qualitative and quantitative multi-elemental analysis of major, minor and trace elements in samples from almost every conceivable field of scientific on technical interest. Am-Be Neutron source was used. The mass of sodium found in 2.103 gm. of irradiated sample is 0.034861216 gm.; which means 1.65 % of the irradiated sample is sodium