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Laser ablation of calcium and aluminium atoms as a particle source for ion trap
Grim, Jakub ; Pekař, Zdeněk ; Pham, Minh Tuan ; Číp, Ondřej
Laser ablation is an effective method for generating particles from a variety of materials, including those with high evaporation temperatures such as aluminum. The use of high-energy laser pulses enables controlled evaporation of the material and the creation of an ablation crater. Successful results have been obtained in a pilot setup for the generation of neutral calcium and aluminium atoms by laser ablation. The method is being compared with thermal resistance oven in order to optimize the prosec generation of these particles. Subsequent spectroscopic measurements on the generated atoms are performed to optimize the absorption and emission of photons for subsequent ionization in the ion trap. A study of the transitions of neutral Ca and Al atoms shows that laser ablation provides a more efficient generation of atoms with the possibility of greater control over the process.
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The spectroscopy of a cloud of Calcium atoms for the experiment of laser cooling
Grim, Jakub ; Pham, Minh Tuan (referee) ; Číp, Ondřej (advisor)
The thesis is focused on the research on methods of generating calcium atoms into ion traps. To be specific, it is a pulse laser ablation method and generating by the calcium heat oven heated by electric current, which is currently being used. Part of the thesis is the design of experimental apparatus for the generation of calcium atoms including vacuum and optical assembly and subsequent experimental assembly itself according to design. At the end, there is an experiment, where is used electric current for heating the oven, ablation laser for ablation of calcium atoms and fluorescence spectroscopy for detection of generated neutral calcium atoms.
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Measurement of magnetic field stability using 40Ca+ ion
Pham, Minh Tuan ; Lešundák, Adam ; Čížek, Martin ; Podhora, L. ; Řeřucha, Šimon ; Jedlička, Petr ; Slodička, L. ; Lazar, Josef ; Číp, Ondřej
One of the main limitations in the long-term measurement of the clock transition's absolute frequency is the magnetic field's fluctuation. The time-varying fluctuation of the external magnetic field leads to frequency shifts of the Zeeman components, thereby reducing the optical clock's frequency stability over time. Currently, optical atomic references are usually implemented with the help of a single ion. However, scaling the number of ions to higher values brings an indisputable benefit in the form of a high signal-to-noise ratio and, thus to the efficiency of the entire measurement process. In this case, the ions are spread over a large area, forming so-called ionic Coulomb crystals. In addition to the spatial stability of the magnetic field, the homogeneity of the magnetic field is also significant when working with Coulomb crystals. Excessive magnetic perturbation can be greatly reduced by covering the assembly with a magnetic shield or by using permanent magnets instead of conventionally used magnetic coils. Another method is averaging over multiple-level transitions. This contribution presents a simple method for measuring the stability of the magnetic field at the ion position.
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Laboratory astrochemistry and applications of computer simulations
Roučka, Štěpán ; Hrach, Rudolf (advisor) ; Bonaventura, Zdeněk (referee) ; Novák, Stanislav (referee)
This work is focused on laboratory studies of ion chemistry at conditions relevant for astrophysics. The three main outcomes of the thesis are: (1) The experimental study of the reaction rate coefficient of the associative detachment reaction H- + H -> H2 + e-; measurement of the thermal rate coefficient at the temperatures in the range 10-135 K is described. (2) The design of a novel apparatus for detecting the electrons produced in the RF trap and measuring their energy; numerical simulations and preliminary experimental results are presented. (3) The development of a model of the electron cooling in the afterglow plasma and the application of the model in the analysis of the H3+ recombination measurements.
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The spectroscopy of a cloud of Calcium atoms for the experiment of laser cooling
Grim, Jakub ; Pham, Minh Tuan (referee) ; Číp, Ondřej (advisor)
The thesis is focused on the research on methods of generating calcium atoms into ion traps. To be specific, it is a pulse laser ablation method and generating by the calcium heat oven heated by electric current, which is currently being used. Part of the thesis is the design of experimental apparatus for the generation of calcium atoms including vacuum and optical assembly and subsequent experimental assembly itself according to design. At the end, there is an experiment, where is used electric current for heating the oven, ablation laser for ablation of calcium atoms and fluorescence spectroscopy for detection of generated neutral calcium atoms.
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Laboratory studies of ion-molecule reactions with molecular and atomic hydrogen at temperatures relevant to astrochemistry
Mulin, Dmytro ; Glosík, Juraj (advisor) ; Kotrík, Tomáš (referee) ; Španěl, Patrik (referee)
The results of the laboratory study of reaction rate coefficients of several ion- molecule reactions with atomic and molecular hydrogen and molecular deuterium at low temperatures are presented in the thesis. The reaction rate coefficients of the N+ and H+ reaction with H2 were measured with respect to the nuclear spin configuration and rotational excitation of H2. The reactions of anions were a subject of the isotope exchange and isotope effect study. The measurements of the rate coefficients of H2O and D2O formation in the reaction of O- with H2 and D2, isotope exchange reactions OH- + D2 and OD- + H2, and associative detachment and charge transfer channels of D- + H interaction were performed. Experiments were carried out using an AB-22PT instrument with an ion trap. It has producing, guiding, trapping, and detecting systems for ions and a separate source of atomic H. The cooling system allowed to measure the temperature dependencies of the reaction rate coefficients at temperatures relevant to astrochemistry (10 K - 300 K)
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Reactions of Hydrogen Molecules with Ions and Recombination of H+3 Ions with Electrons at Cryogenic Temperatures
Hejduk, Michal ; Glosík, Juraj (advisor) ; Čížek, Martin (referee) ; Votava, Ondřej (referee)
We studied how distribution of nuclear-spin states of H+ 3 ions or H2 molecules influence rate coefficients of H+ 3 -electron recombination or reactions of H2 with N+ or H+ , with regard to kinetic and internal temperatures of the reactants. Experiments were carried out in plasma environment or in an ensemble of ions in an ion trap. Main diagnostic methods were the Langmuir probe diagnos- tics, laser absorption- and mass spectroscopy. The distribution of nuclear spin states (para and ortho) was varied using a specially constructed para-hydrogen generator. We performed pioneer measurements of the rate coefficients for the nuclear-spin-state-selective binary and ternary H+ 3 -electron recombination in thermalised plasma. We performed studies of N+ + para/ortho-H2 reaction with high accuracy and interpreted the results as dependent on fine structure states of N+ ions. We measured a temperature dependence of the rate coeffi- cients for radiative and ternary channels of H+ + para/ortho-H2 association. 1
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Laboratory astrochemistry and applications of computer simulations
Roučka, Štěpán ; Hrach, Rudolf (advisor) ; Bonaventura, Zdeněk (referee) ; Novák, Stanislav (referee)
This work is focused on laboratory studies of ion chemistry at conditions relevant for astrophysics. The three main outcomes of the thesis are: (1) The experimental study of the reaction rate coefficient of the associative detachment reaction H- + H -> H2 + e-; measurement of the thermal rate coefficient at the temperatures in the range 10-135 K is described. (2) The design of a novel apparatus for detecting the electrons produced in the RF trap and measuring their energy; numerical simulations and preliminary experimental results are presented. (3) The development of a model of the electron cooling in the afterglow plasma and the application of the model in the analysis of the H3+ recombination measurements.
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