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Novostavba bytového domu v Bystřici nad Pernštejnem
Schauer, Petr ; Pilný, Ondřej (oponent) ; Kalousek, Lubor (vedoucí práce)
Předmětem této bakalářské práce je projektová dokumentace k Novostavbě bytového domu v Bystřici nad Pernštejnem. Řešený objekt leží na severozápadním okraji města. Jedná se o třípodlažní nepodsklepený objekt. V druhém a třetím nadzemním podlaží se rozprostírá sedm bytových jednotek, o velikostech 1+KK a 2+KK. V prvním nadzemním podlaží se nachází čtyři garážová stání se sklepními kójemi. Součástí jsou tři samostatné sklepní kóje, technická místnost, kočárkárna a úklidová místnost. Jedná se o zděný objekt z vápenopískových cihel. Konstrukční systém je smíšený a založen na základových pasech. Stropní konstrukce jsou navrženy jako monolitické stropní desky. Zastřešení je řešeno jako jednoplášťová plochá střešní konstrukce. Objekt je dále vybaven výtahem a bezbariérovým přístupem. Před objektem se nacházejí čtyři venkovní stání, z toho jedno pro osoby se sníženou schopností pohybu. Přístup do budovy je umožněn po zpevněných plochách. Celý objekt je zateplen systémem ETICS. Fasádní barvy jsou navrženy v odstínech bílé a šedé s antracitovými výplněmi otvorů.
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Novostavba bytového domu v Bystřici nad Pernštejnem
Schauer, Petr ; Pilný, Ondřej (oponent) ; Kalousek, Lubor (vedoucí práce)
Předmětem této bakalářské práce je projektová dokumentace k Novostavbě bytového domu v Bystřici nad Pernštejnem. Řešený objekt leží na severozápadním okraji města. Jedná se o třípodlažní nepodsklepený objekt. V druhém a třetím nadzemním podlaží se rozprostírá sedm bytových jednotek, o velikostech 1+KK a 2+KK. V prvním nadzemním podlaží se nachází čtyři garážová stání se sklepními kójemi. Součástí jsou tři samostatné sklepní kóje, technická místnost, kočárkárna a úklidová místnost. Jedná se o zděný objekt z vápenopískových cihel. Konstrukční systém je smíšený a založen na základových pasech. Stropní konstrukce jsou navrženy jako monolitické stropní desky. Zastřešení je řešeno jako jednoplášťová plochá střešní konstrukce. Objekt je dále vybaven výtahem a bezbariérovým přístupem. Před objektem se nacházejí čtyři venkovní stání, z toho jedno pro osoby se sníženou schopností pohybu. Přístup do budovy je umožněn po zpevněných plochách. Celý objekt je zateplen systémem ETICS. Fasádní barvy jsou navrženy v odstínech bílé a šedé s antracitovými výplněmi otvorů.
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Stable Ce4+ centres - a tool to optimize cathodoluminescence performance in garnet scintillators
Lalinský, Ondřej ; Schauer, Petr ; Rathaiah, M. ; Kučera, M.
Garnet single crystals are widely used as scintillators in electron detectors. Cerium activated lutetium aluminum garnet Cex:Lu3-xAl5O12 (LuAG:Ce) is a promising example of such material for these applications. This is mainly due to its high light yield (LY) of 25 kph/MeV, short decay time of 60–80 ns, high atomic density (6.7 g/cm3), and high radiation stability with no hygroscopicity. The cathodoluminescence (CL) performance can be improved by Ga and Gd doping the garnet matrix. Proper admixture of these elements can increase the LY to 50–60 kph/MeV in addition to eliminating unwanted slower decay components. There was an idea that further decay acceleration can be achieved by doping the garnet with monovalent (Li+) or divalent ions (Mg2+, Ca2+). This should increase the valency of some Ce3+ centres to Ce4+ which should better compete with electron traps, and thus accelerate the decay. Our previous work proved the same decay trend, however, at a price of the LY. Such LY loss may induce the idea, if the stable Ce4+ centres are really participating in Ce3+ emission.
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New detectors for low-energy BSE
Lalinský, Ondřej ; Schauer, Petr ; Kučera, M. ; Hanuš, M. ; Lučeničová, Z.
Backscattered electrons (BSE) are mostly used to study the specimen’s topography. Nowadays, low energy (units of keV) electron beam imaging is often necessary for example for the research of nanomaterials, biomaterials or semiconductors. Because BSE detectors are mostly non-accelerating or low-accelerating, electrons with approximately the same energy as primary beam (PB) have to be detected. Therefore, BSE detectors need to become optimized for such low-energy electrons. For the scintillation detectors, the biggest problem probably lies in the scintillator. Semiconductor detectors aren’t studied in this work. Cerium activated bulk single crystals of yttrium aluminium garnet (YAG:Ce)Ce(X):Y(3-X)Al(5)O(12) are widely used as scintillators for the detection of high-energy backscattered electrons (BSE). However, commonly used YAG:Ce single crystal strongly loses its light yield (LY) with the decrease of the PB energy. As possible available alternatives for this application, bulk single crystals of yttrium aluminium perovskite (YAP:Ce) Ce(x)Y(1-X)AlO(3) and CRY018 can be predicted. However, similar LY drop can be expected also with these scintillators.
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Performance of YAG:Ce Scintillators for Low-Energy Electron Detectors in S(T)EM
Lalinský, Ondřej ; Bok, Jan ; Schauer, Petr ; Frank, Luděk
Cerium activated single crystals of yttrium aluminium garnet (YAG:Ce) Y3-xCexAl5O12 are widely used as scintillators in electron detectors for S(T)EM. Nowadays, it is sometimes necessary to detect low-energy electrons without post-acceleration. In such cases, extremely sensitive detectors are required that are able to detect even electrons with energies of only hundreds of eV while avoiding charging of the scintillator surface. However, commonly used scintillators strongly lose their light yield with the decrease of the incident electron energy. Moreover, a thinner conductive layer on the scintillator surface has to be used to allow low-energy electrons to pass through. Possible charging of the surface negatively affects its cathodoluminescence (CL) light yield. The low-energy electron excitation takes place closer to the scintillator surface where damage can be expected owing to its preparation, which also reduces the CL light yield. The aim was to study the influence of the scintillator and its conductive layer on the low-energy electron detection efficiency.
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Innovation possibilities of scintillation electron detector for SEM
Schauer, Petr ; Bok, Jan
To evaluate performance of a scintillation detection system for SEM, it is necessary to consider many scintillator parameters. Various attributes of the scintillator for the SEM electron detector are listed in. The very important parameters are those affecting the detective quantum efficiency (DQE) which is primarily a measure of image noise. Not a less important indicator of image quality is the modulation transfer function (MTF) which describes the ability to show fine image details. Therefore, using a scanning imaging system, the detector bandwidth, which is given especially by the scintillator decay time, is the key to the good MTF. Currently, the YAG:Ce single crystal scintillator (introduced already in 1978 having somewhat limiting decay characteristic is the most frequently used scintillator in the SEM. The aim of this paper is to outline possibilities of scintillator innovation to get the improved MTF and DQE.
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Current state and prospects of scintillation materials for detectors in SEM
Schauer, Petr ; Bok, Jan
The two principal quantities are important for assessing the quality of each imaging system. Firstly, it is the detective quantum efficiency (DQE), which is primarily a measure of image noise. As the DQE is determined by signal to noise ratio (SNR), the efficient and noise-free components are the key to the high DQE. Second, not less important indicator of image quality is also the modulation transfer function (MTF). MTF describes the ability of adjacent pixels to change from black to white in response to patterns of varying spatial frequency, and hence it determines the actual capability to show fine detail, whether with full or reduced contrast. Using a scanning imaging system the fast components are the key to the good MTF. In a scintillation electron detector of scanning electron microscope (SEM) the scintillator is the most crucial component, because it significantly influences both the DQE and MTF. The aim of this study is to assess the scintillation materials suitable for SEM detectors characterized by the both high efficiency and fast decay characteristic.
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Quality assessment of scintillation detector in SEM using MFT
Bok, Jan ; Schauer, Petr
One of the recent trends in S(T)EM is increasing of the e-beam scanning speed. In general, higher speeds decrease object degradation and prevent image artifacts caused by slow electrical discharging. However, the increase of the scanning speed is limited by the time response of the segnal-electron detector. When the detector response is slower than the scanning speed, it can have negative influence to the quality of the scanned image, such as contrast reduction and image blurring. Usually, the rise and fall edges of the time response curve to a square electron pulse have more complex form, such as a multi-exponential function of time. Evaluate and compare the time-dependent edges in contex of their influence on the image quality is rather complicated. Therefore, we propose to express the detector time response by the modulation transfer function (MTF), which contains all relevant information. It can give the answer to the important question, what maximum scanning speed can be used not to significantly decrease the image quality.
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