Protonnyalábos mikromegmunkálás = Proton beam Micromachinig

A téma keretében a mikromegmunkálás módszerét telepítettük az ATOMKI pásztázó proton mikroszondájához. Második lépésben különböző nyomdetektor és más reziszt anyagokat vizsgáltunk a mikromegmunkálás szempontjából. A megmunkált anyagok különböző jellemzőit vizsgáltuk a besugárzási paraméterek függvényében. Az előállított eszközök (mikrostruktúrák) alkalmazási lehetőségeit fel kívántuk kutatni, mikrostruktúrákat állítottuk elő demonstrációs és konkrét alkalmazási célból. A világon második kutatócsoport lettünk e témában, szerepünk azonban nem másodrendű. Kihasználva saját adottságainkat, a nemzetközi irodalomhoz új kutatási eredményekkel járultunk hozzá. Az ATOMKI pásztázó proton mikroszondája így egy új, perspektivikus alkalmazási területet nyert. | We have installed the Proton Beam Micromachining (PBM) / P-beam Writing (PBW) method on the Scanning Nuclear Microprobe of ATOMKI. We have investigated various solid state nuclear track detector and other resist materials for micromachining properties. We have characterized various properties of materials as a function of irradiation parameters. We have explored the potential application areas of the produced microstructures. We have created products for demonstration and real application purposes. We became the second research group in the world in this field, but our role is not of secondary importance. Exploiting our resources, we have added new scientific results to the literature. The Scanning Nuclear Microprobe of ATOMKI has gained a new, prosperous application area

Can the ions be guided with MeV/amu energies? The case of the 1 MeV proton microbeam

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Tilted pillar array fabrication by the combination of proton beam writing and soft lithography for microfluidic cell capture Part 2: Image sequence analysis based evaluation and biological application

As a continuation of our previously published work, this paper presents a detailed evaluation of a microfabricated cell capture device utilizing a doubly tilted micropillar array. The device was fabricated using a novel hybrid technology based on the combination of proton beam writing and conventional lithography techniques. Tilted pillars offer unique flow characteristics and support enhanced fluidic interaction for improved immuno-affinity based cell capture. The performance of the microdevice was evaluated by an image sequence analysis based in-house developed single cell tracking system. Individual cell tracking allowed in-depth analysis of the cell-chip surface interaction mechanism from hydrodynamic point of view. Simulation results were validated by using the hybrid device and the optimized surface functionalization procedure. Finally, the cell capture capability of this new generation microdevice was demonstrated by efficiently arresting cells from a HT29 cellline suspension

Proton and electron irradiations of CH4:H2O mixed ices

The organic chemistry occurring in interstellar environments may lead to the production of complex molecules that are relevant to the emergence of life. Therefore, in order to understand the origins of life itself, it is necessary to probe the chemistry of carbon-bearing molecules under conditions that simulate interstellar space. Several of these regions, such as dense molecular cores, are exposed to ionizing radiation in the form of galactic cosmic rays, which may act as an important driver of molecular destruction and synthesis. In this paper, we report the results of a comparative and systematic study of the irradiation of CH4:H2O ice mixtures by 1 MeV protons and 2 keV electrons at 20 K.We demonstrate that our irradiations result in the formation of a number of new products, including both simple and complex daughter molecules such as C2H6, C3H8, C2H2, CH3OH, CO, CO2, and probably also H2CO. A comparison of the different irradiation regimes has also revealed that proton irradiation resulted in a greater abundance of radiolytic daughter molecules compared to electron irradiation, despite a lower radiation dose having been administered. These results are important in the context of the radiation astrochemistry occurring within the molecular cores of dense interstellar clouds, as well as on outer Solar System objects.Comment: Published as an open access article in the MDPI journal Atom

Proton and Electron Irradiations of CH4:H2O Mixed Ices

The organic chemistry occurring in interstellar environments may lead to the production of complex molecules that are relevant to the emergence of life. Therefore, in order to understand the origins of life itself, it is necessary to probe the chemistry of carbon-bearing molecules under conditions that simulate interstellar space. Several of these regions, such as dense molecular cores, are exposed to ionizing radiation in the form of galactic cosmic rays, which may act as an important driver of molecular destruction and synthesis. In this paper, we report the results of a comparative and systematic study of the irradiation of CH4 :H2O ice mixtures by 1 MeV protons and 2 keV electrons at 20 K. We demonstrate that our irradiations result in the formation of a number of new products, including both simple and complex daughter molecules such as C2H6, C3H8, C2H2, CH3OH, CO, CO2, and probably also H2CO. A comparison of the different irradiation regimes has also revealed that proton irradiation resulted in a greater abundance of radiolytic daughter molecules compared to electron irradiation, despite a lower radiation dose having been administered. These results are important in the context of the radiation astrochemistry occurring within the molecular cores of dense interstellar clouds, as well as on outer Solar System objects

Bombardment of CO ice by cosmic rays: I. Experimental insights into the microphysics of molecule destruction and sputtering

We present a dedicated experimental study of microscopic mechanisms controlling radiolysis and sputtering of astrophysical ices due to their bombardment by cosmic ray ions. Such ions are slowed down due to inelastic collisions with bound electrons, resulting in ionization and excitation of ice molecules. In experiments on CO ice irradiation, we show that the relative contribution of these two mechanisms of energy loss to molecule destruction and sputtering can be probed by selecting ion energies near the peak of the electronic stopping power. We have observed a significant asymmetry, both in the destruction cross section and the sputtering yield, for pairs of ion energies corresponding to same values of the stopping power on either side of the peak. This implies that the stopping power does not solely control these processes, as usually assumed in the literature. Our results suggest that electronic excitations represent a significantly more efficient channel for radiolysis and, possibly, also for sputtering of CO ice. We also show that the charge state of incident ions as well as the rate for CO$^+$ production in the ice have negligible effect on these processes.Comment: Accepted for publication in Ap

Sulfur Ion Implantations Into Condensed CO2: Implications for Europa

The ubiquity of sulfur ions within the Jovian magnetosphere has led to suggestions that the implantation of these ions into the surface of Europa may lead to the formation of SO2. However, previous studies on the implantation of sulfur ions into H2O ice (the dominant species on the Europan surface) have failed to detect SO2 formation. Other studies concerned with similar implantations into CO2 ice, which is also known to exist on Europa, have offered seemingly conflicting results. In this letter, we describe the results of a study on the implantation of 290 keV S+ ions into condensed CO2 at 20 and 70 K. Our results demonstrate that SO2 is observed after implantation at 20 K, but not at the Europa-relevant temperature of 70 K. We conclude that this process is likely not a reasonable mechanism for SO2 formation on Europa, and that other mechanisms should be explored instead