|
|
The comparison of plastic scintillation detector with detector NaI(Tl), their utility and dosimetric properties. 1. The plastic scintillator detector 2. NaI(Tl) detector
VÁVRA, Jiří
This bachelor thesis deals with ionizing radiation, especially with its detection by another name measurement, in two scintillation detectors of ionizing radiation, a plastic scintillation detector and the detector of thallium-activated sodium iodide by another name NaI (Tl). The first description of an ionizing radiation in general terms is in the first chapter, eg. what is ionizing radiation and radioactivity, types of radioactive decay are listed and explained, further there are explained the interaction of ionizing radiation. Subsequently there are shown the passage of ionizing radiation by the material and in shortly way sources of ionizing radiation. Then there are quantities and units characterizing the radiation field in the space and the radiation exposure to the substance. As I do not deal with the effects of ionizing radiation on the organism in my bachelor thesis, there are not listed quantities and units associated with it. After information about ionizing radiation there is general information about scintillation detectors, which ideal properties should have scintillation material, the principle of scintillation detectors. In particular, there are information about mentioned detectors and their properties. The aim of the thesis is to compare the plastic scintillation detector with the detector NaI (Tl), which are used very often nowadays. Then to compare functional characteristics of these detectors, which are used in dosimetry, in industry, healthcare, and others. Then to compare efficiency, resolution, energy dependence, etc. with using the measurement of point emitters. There were used to measure the detectors of the same size for effective comparison, then radionuclide sources emitting the ionizing radiation with different energies in the entire measurement range. All measurements were made over a sufficiently long period and in the lead shielding to avoid interference from other (natural) radiation. The resulting spectras are indicated by peaks of the radionuclides to be a distinct difference in the resolution at used detectors, then there is graphically illustrated the light yield of detectors. I performed the energy calibration of both detectors, the efficiency calibration of the detector only at NaI (Tl) detector. It was not possible to implement this calibration at a plastic detector mainly due to the bad resolution of the detector and the resulting lack of calibration points. This problem has resulted that the energy calibration curve is not linear at a plastic detector; therefore, it is not entirely optimal. Both formed curves are essentially ideal at the detector NaI (Tl). It is shown from the measured spectras and their evaluation that the detector NaI (Tl) has a significantly better resolution and better light yield. So why and for what to use a plastic scintillator detector? The fact is discussed at the end of this thesis. Although plastic detectors have low spectrometric properties, they are used very often. Mainly because they are several times cheaper and they can be produced in large sizes and different shapes for a reasonable price. They are used for quick selection, thus determining whether the measured object emits ionizing radiation or not. NaI (Tl) detectors are used to identify radionuclides because of their relatively high resolution.
|
|
|
Design of a comparator with offset compensation in CMOS technology
Hylský, Josef ; Vávra, Jiří (referee) ; Kledrowetz, Vilém (advisor)
This work contains basic knowledge about comparators and its design in the CMOS technology. The first chapter deals with a wide use of a comparator, its charakteristice and the CMOS technology that is used to produce the transistors for the implementation of comparators. In the two following chapters there are examples of connexion of comparators, the design of the two-stage open loop comparator and improving of its charakteristic. The preamplifier and its application in high-speed Latchs comparators are introduced in the next chapter. The design of the comparator are introduced inthe next chapter. The design of the comparator and its application in high-speed comparators are introduced in the next chapter.
|
|
|
Operating amplifier tester
Zápeca, Jan ; Khateb, Fabian (referee) ; Vávra, Jiří (advisor)
The bachelor's thesis tries to describe the evolution of the device designated for testing of the operational amplifier 1458. The evolution is associated with theoretical preparation useful for future application of obtained knowledge. This knowledge is presented by measuring methods which are suitably chosen and by choice of parts. Consequently, particular coplexes join together and the conception of future operational amplifier 1458 tester is created. The conception of tester in logically connected blocs form leads to creation of electrical scheme and also to smooth transition from theoretical part to practical application of knowledge. The tester is designed as a digital device. The microcontroller becomes the principal control component. The microcontroller defines accurately the final function of device. Tha last part of bachelor's thesis describes the tester manufacturing. The conclusion respresents the summary of knowledge and results of bachelor´s thesis. Functional device, which is the result of bachelor´s thesis, detects the operational amplifier defect in 2 levels - the gain fault and the defect of overcurrents. The tester identifies explicitly whether tested operational amplifier 1458 is defective.
|
|
|
Low voltage low power current conveyor CCII
Kadaňka, Petr ; Vávra, Jiří (referee) ; Khateb, Fabian (advisor)
This paper is focused on comparing CCIIs by their construction principle. It researchs differences between gate-driven and bulk-driven approach, and between design based on current mirrors or operational amplifier. Designed current conveyor functionality is verified by SPICE simulation. Main objective of this work is to obtain current conveyor with lowest possible supply voltage and minimal power consumption.
|
|
| |
|
|
Current-Input Current-Output Active Circuit Elements and their Applications
Vávra, Jiří ; Sedláček, Jiří (referee) ; Maschke, Jan (referee) ; Biolek, Dalibor (advisor)
The thesis deals with definitions of new current- or mixed-mode circuit elements and their implementations and applications. Based on the analysis of the state-of-the-art, novel application circuits employing the above circuit elements are designed. For the purpose of the experimental verification, the active elements are implemented via commercial integrated circuits, and their applications are simulated via PSpice. The application circuits are focused on frequency filters, rectifiers, oscillators, and current-copy circuits. Selected applications are analyzed with respect on real influences, and measurements on circuit prototypes are also performed.
|
|
| |
|
|
Integrated D/A converter for automotive applications
Kubáň, Marián ; Vávra, Jiří (referee) ; Kolka, Zdeněk (advisor)
Presented thesis deals with the conceptual design of an integrated 11-bit, dual, bipolar, DA converter with current output. Converter is designed in I3T50E proprietary technology of ONSemiconductor. The converter is of a segmented architecture with 6 MSB bits unary and 4 LSB bits binary weighted. Work also describes basic general properties of DA converters, topology examples with regard to the project assignment. The design is assumed for automotive industrial field of application. The operating temperature range is from -40 Deg.C. up to 175 Deg.C. The qualities of produced integrated converter are measured and results are discussed.
|
|
| |
|
| |
guest ::
RSS feed.