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Characteristics of semiconductor BSE electron microscope detector
Plot, Vítězslav ; Hubálek, Jaromír (referee) ; Boušek, Jaroslav (advisor)
The thesis deals with the characterization of a semiconductor detector of backscattered electrons. The theoretical part describes two types of electron microscopes, the interaction of the primary beam with the sample and individual types of electrons and radiation arising during the interaction. The most used types of electron detectors in scanning electron microscope are summarized. The basic characteristics of the semiconductor backscattered electron detector and their measurement methods are described. The experimental part deals with measuring the characteristics of the detector made by Delong Instruments and comparing it with commercially available detectors. Volt-ampere characteristic and dark current, the dependence of the gain on the accelerating voltage, as well as the time response of the detector were measured.
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Cross section measurement in reactor spectrum: 55Mn(n,2n), 90Zr(n,2n), 127I(n,2n)
Burianová, Nicola ; Košťál, Michal (advisor) ; Krtička, Milan (referee)
This diploma thesis deals with the validation of spectral average cross-sections (SACS) of 55 Mn(n,2n)54 Mn, 90 Zr(n,2n)89 Zr, 127 I(n,2n)126 I reactions in well-defined LR-0 reactor spectrum. The measurement of SACS for selected reactions is of high interest because they are used for the practical reactor dosimetry. Various experiments for description of neutron field in reactor and detector characterization, which are necessary for validation, are described. The spectral average cross-sections are derived from Net Peak Areas of irradiated samples measured using a semiconductor high purity germanium detector. Obtained result were compared with MCNP6 calculations using ENDF/B-VII.0, ENDF/B-VII.1, JEFF-3.1, JEFF-3.2, JENDL-3.3, JENDL-4, ROSFOND-2010, CENDL-3.1 and IRDFF nuclear data libraries. Notable discrepancies were found in 90 Zr(n,2n)89 Zr and 127 I(n,2n)126 I reactions. This thesis also contains a theoretical basis for the interaction of neutrons with matter.
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Cross section measurement in reactor spectrum: 55Mn(n,2n), 90Zr(n,2n), 127I(n,2n)
Burianová, Nicola ; Košťál, Michal (advisor) ; Krtička, Milan (referee)
This diploma thesis deals with the validation of spectral average cross-sections (SACS) of 55 Mn(n,2n)54 Mn, 90 Zr(n,2n)89 Zr, 127 I(n,2n)126 I reactions in well-defined LR-0 reactor spectrum. The measurement of SACS for selected reactions is of high interest because they are used for the practical reactor dosimetry. Various experiments for description of neutron field in reactor and detector characterization, which are necessary for validation, are described. The spectral average cross-sections are derived from Net Peak Areas of irradiated samples measured using a semiconductor high purity germanium detector. Obtained result were compared with MCNP6 calculations using ENDF/B-VII.0, ENDF/B-VII.1, JEFF-3.1, JEFF-3.2, JENDL-3.3, JENDL-4, ROSFOND-2010, CENDL-3.1 and IRDFF nuclear data libraries. Notable discrepancies were found in 90 Zr(n,2n)89 Zr and 127 I(n,2n)126 I reactions. This thesis also contains a theoretical basis for the interaction of neutrons with matter.
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