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Influence of the laser mixture composition on the existence of the dinitrogen bands
Morávek, Matěj Jan ; Hrachová, Věra (advisor) ; Kudrna, Pavel (referee)
This project studies mixtures of helium, nitrogen and carbon dioxid, widely used in so called CO2 lasers. These lasers are classified as discharge lasers. In the case of low output lasers is often used a DC glow discharge. We can find bands so called first and second positive systems of a dinitrogen molecule in an emission spectrum of the glow discharge. It is possible to deduce energetic balance and a vibrational temperature from these bands. The vibrational temperature was studied by the vibrational spectroscopy of dinitrogen molecule for various discharge currents and pressures and for various distribution of nitrogen in the mixture (we will start with an industrial mixture LASAL 63).
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Study of plasma in the mixtures with molecular gas at wide pressure range
Morávek, Matěj Jan ; Hrachová, Věra (advisor) ; Mazánková, Věra (referee) ; Pavlík, Jaroslav (referee)
Study of plasma in the mixtures with molecular gas at wide pressure range Matěj Jan Morávek Abstract: The positive column of DC glow discharge sustained in oxygen and oxygen-nitrogen mixtures has been studied in two discharge tubes of the same shape made from different materials (Silica and Pyrex glass) for total pressures 650 - 2000 Pa and discharge currents up to 40 mA. Various parameters of the discharge - axial electric field strength, concentration of electrons and emission spectra - were studied with emphasis placed on transition region between low- and high-gradient form of the positive column. We have focused on the qualitative and quantitative analysis of the differences in emission spectra for both particular forms and the transitional region between them. The impact of 1 % admixture of nitrogen was also studied.
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Low temperature plasma diagnostics by Cavity Ring-Down Spectroscopy
Kassayová, Miroslava ; Dohnal, Petr (advisor) ; Morávek, Matěj Jan (referee)
Low temperature plasma occurs in interstellar gas clouds, solar system, ionosp- here of the Earth and is used in plasmatic technologies. The study of the reactions of simple atomic or molecular ions with molecules and electrons in low temperature plasma allows better understanding of chemical processes in interstellar gas clouds and atmospheres of gas giants and gives feedback for quantum mechanical calcula- tions. It also allows to connect new facts gained via astronomical observations. The parameters of plasma (kinetic and rotational temperature of ions, their concentra- tions, etc.) may vary and many diagnostic technics are used to determine them. The aim of this bachelor thesis is to find suitable infrared transitions of N2H+ and utilize them for spectroscopical study of the electron - ion recombination of N2H+ ions with electrons. 1
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Study of laser mixture in the large pressure region
Morávek, Matěj Jan ; Hrachová, Věra (advisor) ; Kudrna, Pavel (referee)
This work studies discharge plasma in a mixture of gases, similar to that used in the so-called CO2-lasers. This mixture consists of CO2, N2 and He. The effect of the mixture composition and discharge parameters (especially pressure, in the range of 266 Pa - 100 kPa) on the distribution of energy in the vibrational levels of nitrogen was examined. This is important parameter for modelling of the discharge plasma. The effect of the mixture composition on the degree of dissociation of the CO2 molecules was also studied. The relative concentration of CO was applied to find the conditions leading to a minimal dissociation of the carbon dioxide. Measurements of radial profiles were also made. Results from two discharge tubes made from different materials were compared. Two types of discharge were utilized to acquire a wide pressure range - low pressure DC glow discharge in the range of 266 Pa to 1330 Pa and dielectric barrier discharge in the range of 5 kPa to 100 kPa. Both discharges are used in commercial CO2-lasers. We observed a descending dependence of the vibrational temperature on the pressure and a big step caused by increased occurrence of standing ionizing waves in the mixtures with low nitrogen ratio. Vibrational temperature in the DBD was markedly lower than in the DC GD, because of the...
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Influence of the laser mixture composition on the existence of the dinitrogen bands
Morávek, Matěj Jan ; Hrachová, Věra (advisor) ; Kudrna, Pavel (referee)
This project studies mixtures of helium, nitrogen and carbon dioxid, widely used in so called CO2 lasers. These lasers are classified as discharge lasers. In the case of low output lasers is often used a DC glow discharge. We can find bands so called first and second positive systems of a dinitrogen molecule in an emission spectrum of the glow discharge. It is possible to deduce energetic balance and a vibrational temperature from these bands. The vibrational temperature was studied by the vibrational spectroscopy of dinitrogen molecule for various discharge currents and pressures and for various distribution of nitrogen in the mixture (we will start with an industrial mixture LASAL 63).
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