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Papers by Miklós Kiss

Journal of Central European Green Innovation

A nehéz magok (vas felett) neutronbefogási folyamatok során keletkeznek. Ezen elemek gyakoriságát... more A nehéz magok (vas felett) neutronbefogási folyamatok során keletkeznek. Ezen elemek gyakoriságát jellemzi az elemgyakoriság, az izotóp gyakoriság, illetve a magok gyakorisága, vagyis a magok egyedi gyakorisága. Nagyon hasznosnak tűnik a magok egyedi gyakoriságának vizsgálata. Ez a megközelítés lehetőséget ad új információk kiolvasására a tapasztalt gyakoriságokból. Ami fontos, lehetséges becslést adni, hogy milyen neutronsűrűség szükséges a tapasztalt gyakoriságok reprodukálásához egyensúlyi magszintézist feltételezve. Ez akkor lehetséges, amikor két stabil magot egy nem stabil mag választ el. Ezeken a helyeken vizsgáltuk, hogy milyen neutronsűrűség kell az egyensúlyi magszintézishez.A magok részleges keletkezésének lehetősége egy másik fontos kérdés. Matematikai definíciót találtunk egy egységes interpretációjára annak, hogy egy elágazás mikor zár izotonikusan és mikor nyílik izotopikusan. Egy sokkal kifejezőbb jellemzőt vezettünk be az elágazás jellemzésére, az ún. részleges kele...

Proceedings of XIII Nuclei in the Cosmos — PoS(NIC XIII), 2015

Heavy elements are formed in nucleosynthesis processes. Abundances of these elements can be class... more Heavy elements are formed in nucleosynthesis processes. Abundances of these elements can be classified as elemental abundance, isotopic abundance, and abundance of nuclei. In this work the nuclei are identified by (Z,N), which allows reading out new information from the measured abundances. We are interested in the neutron density required to reproduce the measured abundance of nuclei assuming equilibrium processes. This is only possible when two stable nuclei are separated by an unstable nucleus. At these places we investigated the neutron density required for equilibrium nucleosynthesis both isotopically and isotonically at temperatures of AGB interpulse and thermal pulse phases. We obtained an estimate for equilibrium nucleosynthesis neutron density in most of the cases. Next we investigated the possibility of partial formation of nuclei. We analyzed the meaning of the branching factor. We found a mathematical definition for the unified interpretation of a branching point closed at isotonic case and open at isotopic case. We introduce a more expressive variant of branching ratio called partial formation rate. With these we are capable of determining the characteristic neutron density values. We found that all experienced isotope ratios can be obtained both at K 10 8 temperature and at K 10 3 8 ⋅ temperature and at intermediate neutron density (3 12 cm 10 2 − ⋅ ≤).

Heavy elements (beyond iron) are formed in neutron capture nucleosynthesis processes. We have pro... more Heavy elements (beyond iron) are formed in neutron capture nucleosynthesis processes. We have proposed a simple unified model to investigate the neutron capture nucleosynthesis in arbitrary neutron density environment. We have also investigated what neutron density is required to reproduce the measured abundance of nuclei assuming equilibrium processes. We found both of these that the medium neutron density has a particularly important role at neutron capture nucleosynthesis. About these results most of the nuclei can formed at medium neutron capture density environment e.g. in some kind of AGB stars. Besides these observations our model is capable to use educational purpose.

Journal of Physics: Conference Series, 2010

ISRN Astronomy and Astrophysics, 2013

Studying the published values of Maxwellian-averaged neutron capture cross sections, we found sim... more Studying the published values of Maxwellian-averaged neutron capture cross sections, we found simple phenomenological rules obeyed by the cross sections as a function of proton and neutron numbers. We use these rules to make predictions for cross sections of neutron capture on nuclei with proton number above 83, where very few MACS data are available. These predictions may be useful in certain models of nucleosynthesis of heavy nuclei in stars.

Studying the published values of Maxwellian-averaged neutron capture cross sections, we found sim... more Studying the published values of Maxwellian-averaged neutron capture cross sections, we found simple phenomenological rules obeyed by the cross sections as a function of proton and neutron numbers. We use these rules to make predictions for cross sections of neutron capture on nuclei with proton number above 83, where very few MACS data are available. ese predictions may be useful in certain models of nucleosynthesis of heavy nuclei in stars.

Nearly sixty years after BBFH [1], it is very important to re-investigate neutron capture process... more Nearly sixty years after BBFH [1], it is very important to re-investigate neutron capture processes. Since 1957 everybody has spoken about s-process and r-process, but how are these processes realized in fact? Do s-path and r-path exist, or these are only two useful approximations?
It is the best to investigate the beginnings. How does the formation of nuclei occur starting from seed nucleus Fe-26 ? It is possible that other nuclei can capture a neutron as well, but because of the high abundance of iron, this process is the most important.
The possibility of experimental investigation is very limited, so it is very useful to investigate it through a model. The computational model is almost the only way to look into the details.
There is a simple full network computer model for neutron capture nucleosynthesis [2,3] which was made strictly following Käppeler [4]. In the early 2000s it was possible to run such a simple network model on a computer. In case of this model it was not necessary to exclude any nuclei from the neutron capture process arbitrarily. It is possible to get the order of formation of nuclei by the model step by step. Surprisingly the Fe-60 is formed before the Ni-60 and before any other nuclei above Ni-60 along the s-path.

A former paper of me investigated the conditions which are required to get back the abundance of ... more A former paper of me investigated the conditions which are required to get back the abundance of nuclei (Kiss 2014). According to this investigation the required neutron density (10^10 cm^-3-10^15 cm^-3) is available at the asymptotic giant branch (AGB) stars. How much is the AGB contribution, what part of stellar mass goes through the AGB evolution phase? From this what part returns into the interstellar medium (ISM) Where is the Galactic Fe-60 formed? In this paper these questions are examined. The result is that most stellar matter was or is in AGB stars. The AGB contribution of interstellar medium is greater than the supernovae (SNII) contribution: that is, much more mass goes through AGB stars than core collapsing supernovae.

Heavy elements are formed in nucleosynthesis processes. Abundances of these elements can be class... more Heavy elements are formed in nucleosynthesis processes. Abundances of these elements can be classified as elemental abundance, isotopic abundance, and abundance of nuclei. In this work the nuclei are identified by (Z,N), which allows reading out new information from the measured abundances. We are interested in the neutron density required to reproduce the measured abundance of nuclei assuming equilibrium processes. This is only possible when two stable nuclei are separated by an unstable nucleus. At these places we investigated the neutron density required for equilibrium nucleosynthesis both isotopically and isotonically at temperatures of AGB interpulse and thermal pulse phases. We obtained an estimate for equilibrium nucleosynthesis neutron density in most of the cases. Next we investigated the possibility of partial formation of nuclei. We analyzed the meaning of the branching factor. We found a mathematical definition for the unified interpretation of a branching point closed at isotonic case and open at isotopic case. We introduce a more expressive variant of branching ratio called partial formation rate. With these we are capable of determining the characteristic neutron density values. We found that all experienced isotope ratios can be obtained both at

We prospose a unified model for the nucleosynthesis of heavy (A > 57) elements in stars. The neut... more We prospose a unified model for the nucleosynthesis of heavy (A > 57) elements in stars. The neutron flux can be set to describe neutron capture in arbitrary neutron flux. Our approach solves the coupled differential equations, that describe the neutron capture and decays of 2696 nuclei, numerically without truncating those to include only either capture or decay as traditionally assumed in weak neutron flux (s process). As a result the synthesis of heavy nuclei always evolves along a wide band in the valley of stable nuclei. The observed abundances in the Solar system are reproduced reasonably already in the simplest version of the model. The model predicts that the nucleosynthesis in weak or modest neutron flux produces elements that are traditionally assumed to result in the high neutron flux of supernovae explosions (r process).

Conference Presentations by Miklós Kiss

Back in 1981 it was realized that there is no nationwide competition in physics for the ninth and... more Back in 1981 it was realized that there is no nationwide competition in physics for the ninth and tenth grade high school students. To be able to recognize students talented in physics as early as possible, a new competition named after a famous Hungarian physics teacher Mikola was organized for them. The competition consists of three rounds. The first and second rounds mainly focus on theory and problem solving. The final round consists of both theoretical questions and experiments. The usual venues of the finals are the Berze High School in Gyöngyös (ninth grade) and Leőwey High School in Pécs (tenth grade). This year (2015) the 34th Mikola competition was held.

Heavy elements (beyond iron) are formed in neutron capture nucleosynthesis processes. A simple un... more Heavy elements (beyond iron) are formed in neutron capture nucleosynthesis processes. A simple unified model is proposed to investigate the neutron capture nucleosynthesis in arbitrary neutron density environment. Neutron density required to reproduce the measured abundance of nuclei assuming equilibrium processes is investigated as well. Medium neutron density was found to play a particularly important role in neutron capture nucleosynthesis. Using these findings most of the nuclei can be formed in a medium neutron capture density environment e.g. in certain AGB stars. Besides these observations the proposed model suits educational purposes as well. INTRODUCTION Nearly sixty years after BBFH [1], it is possible and necessary to review and rethink our knowledge about the neutron capture nucleosynthesis. The result of the formation of the nuclei is shown in the various abundances. It is important to mention that the unstable nuclei decayed into stable nuclei and we are only able to observe the abundance of the remaining stable nuclei. "The success of any theory of nucleosynthesis has to be measured by comparison with the abundance patterns observed in nature." – say Käppeler, Beer and Wisshak [2], that is, we need to create such model that gives back the observed abundances.

Journal of Central European Green Innovation

A nehéz magok (vas felett) neutronbefogási folyamatok során keletkeznek. Ezen elemek gyakoriságát... more A nehéz magok (vas felett) neutronbefogási folyamatok során keletkeznek. Ezen elemek gyakoriságát jellemzi az elemgyakoriság, az izotóp gyakoriság, illetve a magok gyakorisága, vagyis a magok egyedi gyakorisága. Nagyon hasznosnak tűnik a magok egyedi gyakoriságának vizsgálata. Ez a megközelítés lehetőséget ad új információk kiolvasására a tapasztalt gyakoriságokból. Ami fontos, lehetséges becslést adni, hogy milyen neutronsűrűség szükséges a tapasztalt gyakoriságok reprodukálásához egyensúlyi magszintézist feltételezve. Ez akkor lehetséges, amikor két stabil magot egy nem stabil mag választ el. Ezeken a helyeken vizsgáltuk, hogy milyen neutronsűrűség kell az egyensúlyi magszintézishez.A magok részleges keletkezésének lehetősége egy másik fontos kérdés. Matematikai definíciót találtunk egy egységes interpretációjára annak, hogy egy elágazás mikor zár izotonikusan és mikor nyílik izotopikusan. Egy sokkal kifejezőbb jellemzőt vezettünk be az elágazás jellemzésére, az ún. részleges kele...

Proceedings of XIII Nuclei in the Cosmos — PoS(NIC XIII), 2015

Heavy elements are formed in nucleosynthesis processes. Abundances of these elements can be class... more Heavy elements are formed in nucleosynthesis processes. Abundances of these elements can be classified as elemental abundance, isotopic abundance, and abundance of nuclei. In this work the nuclei are identified by (Z,N), which allows reading out new information from the measured abundances. We are interested in the neutron density required to reproduce the measured abundance of nuclei assuming equilibrium processes. This is only possible when two stable nuclei are separated by an unstable nucleus. At these places we investigated the neutron density required for equilibrium nucleosynthesis both isotopically and isotonically at temperatures of AGB interpulse and thermal pulse phases. We obtained an estimate for equilibrium nucleosynthesis neutron density in most of the cases. Next we investigated the possibility of partial formation of nuclei. We analyzed the meaning of the branching factor. We found a mathematical definition for the unified interpretation of a branching point closed at isotonic case and open at isotopic case. We introduce a more expressive variant of branching ratio called partial formation rate. With these we are capable of determining the characteristic neutron density values. We found that all experienced isotope ratios can be obtained both at K 10 8 temperature and at K 10 3 8 ⋅ temperature and at intermediate neutron density (3 12 cm 10 2 − ⋅ ≤).

Heavy elements (beyond iron) are formed in neutron capture nucleosynthesis processes. We have pro... more Heavy elements (beyond iron) are formed in neutron capture nucleosynthesis processes. We have proposed a simple unified model to investigate the neutron capture nucleosynthesis in arbitrary neutron density environment. We have also investigated what neutron density is required to reproduce the measured abundance of nuclei assuming equilibrium processes. We found both of these that the medium neutron density has a particularly important role at neutron capture nucleosynthesis. About these results most of the nuclei can formed at medium neutron capture density environment e.g. in some kind of AGB stars. Besides these observations our model is capable to use educational purpose.

Journal of Physics: Conference Series, 2010

ISRN Astronomy and Astrophysics, 2013

Studying the published values of Maxwellian-averaged neutron capture cross sections, we found sim... more Studying the published values of Maxwellian-averaged neutron capture cross sections, we found simple phenomenological rules obeyed by the cross sections as a function of proton and neutron numbers. We use these rules to make predictions for cross sections of neutron capture on nuclei with proton number above 83, where very few MACS data are available. These predictions may be useful in certain models of nucleosynthesis of heavy nuclei in stars.

Studying the published values of Maxwellian-averaged neutron capture cross sections, we found sim... more Studying the published values of Maxwellian-averaged neutron capture cross sections, we found simple phenomenological rules obeyed by the cross sections as a function of proton and neutron numbers. We use these rules to make predictions for cross sections of neutron capture on nuclei with proton number above 83, where very few MACS data are available. ese predictions may be useful in certain models of nucleosynthesis of heavy nuclei in stars.

Nearly sixty years after BBFH [1], it is very important to re-investigate neutron capture process... more Nearly sixty years after BBFH [1], it is very important to re-investigate neutron capture processes. Since 1957 everybody has spoken about s-process and r-process, but how are these processes realized in fact? Do s-path and r-path exist, or these are only two useful approximations?
It is the best to investigate the beginnings. How does the formation of nuclei occur starting from seed nucleus Fe-26 ? It is possible that other nuclei can capture a neutron as well, but because of the high abundance of iron, this process is the most important.
The possibility of experimental investigation is very limited, so it is very useful to investigate it through a model. The computational model is almost the only way to look into the details.
There is a simple full network computer model for neutron capture nucleosynthesis [2,3] which was made strictly following Käppeler [4]. In the early 2000s it was possible to run such a simple network model on a computer. In case of this model it was not necessary to exclude any nuclei from the neutron capture process arbitrarily. It is possible to get the order of formation of nuclei by the model step by step. Surprisingly the Fe-60 is formed before the Ni-60 and before any other nuclei above Ni-60 along the s-path.

A former paper of me investigated the conditions which are required to get back the abundance of ... more A former paper of me investigated the conditions which are required to get back the abundance of nuclei (Kiss 2014). According to this investigation the required neutron density (10^10 cm^-3-10^15 cm^-3) is available at the asymptotic giant branch (AGB) stars. How much is the AGB contribution, what part of stellar mass goes through the AGB evolution phase? From this what part returns into the interstellar medium (ISM) Where is the Galactic Fe-60 formed? In this paper these questions are examined. The result is that most stellar matter was or is in AGB stars. The AGB contribution of interstellar medium is greater than the supernovae (SNII) contribution: that is, much more mass goes through AGB stars than core collapsing supernovae.

Heavy elements are formed in nucleosynthesis processes. Abundances of these elements can be class... more Heavy elements are formed in nucleosynthesis processes. Abundances of these elements can be classified as elemental abundance, isotopic abundance, and abundance of nuclei. In this work the nuclei are identified by (Z,N), which allows reading out new information from the measured abundances. We are interested in the neutron density required to reproduce the measured abundance of nuclei assuming equilibrium processes. This is only possible when two stable nuclei are separated by an unstable nucleus. At these places we investigated the neutron density required for equilibrium nucleosynthesis both isotopically and isotonically at temperatures of AGB interpulse and thermal pulse phases. We obtained an estimate for equilibrium nucleosynthesis neutron density in most of the cases. Next we investigated the possibility of partial formation of nuclei. We analyzed the meaning of the branching factor. We found a mathematical definition for the unified interpretation of a branching point closed at isotonic case and open at isotopic case. We introduce a more expressive variant of branching ratio called partial formation rate. With these we are capable of determining the characteristic neutron density values. We found that all experienced isotope ratios can be obtained both at

We prospose a unified model for the nucleosynthesis of heavy (A > 57) elements in stars. The neut... more We prospose a unified model for the nucleosynthesis of heavy (A > 57) elements in stars. The neutron flux can be set to describe neutron capture in arbitrary neutron flux. Our approach solves the coupled differential equations, that describe the neutron capture and decays of 2696 nuclei, numerically without truncating those to include only either capture or decay as traditionally assumed in weak neutron flux (s process). As a result the synthesis of heavy nuclei always evolves along a wide band in the valley of stable nuclei. The observed abundances in the Solar system are reproduced reasonably already in the simplest version of the model. The model predicts that the nucleosynthesis in weak or modest neutron flux produces elements that are traditionally assumed to result in the high neutron flux of supernovae explosions (r process).

Back in 1981 it was realized that there is no nationwide competition in physics for the ninth and... more Back in 1981 it was realized that there is no nationwide competition in physics for the ninth and tenth grade high school students. To be able to recognize students talented in physics as early as possible, a new competition named after a famous Hungarian physics teacher Mikola was organized for them. The competition consists of three rounds. The first and second rounds mainly focus on theory and problem solving. The final round consists of both theoretical questions and experiments. The usual venues of the finals are the Berze High School in Gyöngyös (ninth grade) and Leőwey High School in Pécs (tenth grade). This year (2015) the 34th Mikola competition was held.

Heavy elements (beyond iron) are formed in neutron capture nucleosynthesis processes. A simple un... more Heavy elements (beyond iron) are formed in neutron capture nucleosynthesis processes. A simple unified model is proposed to investigate the neutron capture nucleosynthesis in arbitrary neutron density environment. Neutron density required to reproduce the measured abundance of nuclei assuming equilibrium processes is investigated as well. Medium neutron density was found to play a particularly important role in neutron capture nucleosynthesis. Using these findings most of the nuclei can be formed in a medium neutron capture density environment e.g. in certain AGB stars. Besides these observations the proposed model suits educational purposes as well. INTRODUCTION Nearly sixty years after BBFH [1], it is possible and necessary to review and rethink our knowledge about the neutron capture nucleosynthesis. The result of the formation of the nuclei is shown in the various abundances. It is important to mention that the unstable nuclei decayed into stable nuclei and we are only able to observe the abundance of the remaining stable nuclei. "The success of any theory of nucleosynthesis has to be measured by comparison with the abundance patterns observed in nature." – say Käppeler, Beer and Wisshak [2], that is, we need to create such model that gives back the observed abundances.