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31	First Principles Calculations of Electron Transport and Structural Damage by Intense Irradiation Ortiz, Carlos January 2009 (has links) First principle electronic structure theory is used to describe the effect of crystal binding on radiation detectors, electron transport properties, and structural damage induced by intense irradiation. A large database containing general electronic structure results to which data mining algorithms can be applied in the search for new functional materials, a case study is presented for scintillator detector materials. Inelastic cross sections for the generation of secondary electron cascades through impact ionization are derived from the dielectric response of an electron gas and evolved in time with Molecular Dynamics (MD). Qualitative and quantitive estimates are presented for the excitation and relaxation of a sample irradiated with Free Electron Laser pulses. A study is presented in where the structural damage on covalent bonded crystals following intense irradiation is derived from a Tight Binding approach and evolved in time with MD in where the evolution of the sample is derived from GW theory for the quasiparticle spectra and a dedicated Boltzmann transport equation for the impact ionization. Condense matter theory electronic structure quasiparticles GW theory molecular dynamics Boltzmann transport electron transport impact ionization structural damage dielectric response structural biology radiation detectors scintillators positron emission tommography Electronic structure Elektronstruktur Semiconductor physics Halvledarfysik Biological physics Biologisk fysik Critical phenomena (phase transitions) Kritiska fenomen (fasövergångar) Functional materials Funktionella material
32	Víceelektrodový systém ionizačního detektoru pro environmentální rastrovací elektronový mikroskop / Multi-electrode system of ionization detector for environmental scanning electrone microscope Uhlář, Vít January 2015 (has links) Thesis deals with environmental scanning electron microscopy and with detection of signal electrons by using ionization detector. First part talks about the principle of environmental scanning electron microscope. Second part describes signals generated by interaction of primary electron beam with sample. Third section explains the principle of impact ionization and ionization detector. Experimental part deals with usage of segmental ionization detector and with measuring of signal amplification from copper and platinum. Thesis also examines arrangement of electrodes of ionisation detector on material contrast and examines also on influence of voltage contrast on base - emitter junction of an NPN bipolar transistor. All experiments were carried out in dependency on saturated water vapour pressure in sample chamber.

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First Principles Calculations of Electron Transport and Structural Damage by Intense Irradiation

Víceelektrodový systém ionizačního detektoru pro environmentální rastrovací elektronový mikroskop / Multi-electrode system of ionization detector for environmental scanning electrone microscope