Rauscher T.,University of Basel |
Rauscher T.,University of Hertfordshire |
Dauphas N.,University of Chicago |
Dillmann I.,Helmholtz Center for Heavy Ion Research |
And 4 more authors.
Reports on Progress in Physics | Year: 2013
A small number of naturally occurring, proton-rich nuclides (the p-nuclei) cannot be made in the s- and r-processes. Their origin is not well understood. Massive stars can produce p-nuclei through photodisintegration of pre-existing intermediate and heavy nuclei. This so-called γ-process requires high stellar plasma temperatures and occurs mainly in explosive O/Ne burning during a core-collapse supernova. Although the γ-process in massive stars has been successful in producing a large range of p-nuclei, significant deficiencies remain. An increasing number of processes and sites has been studied in recent years in search of viable alternatives replacing or supplementing the massive star models. A large number of unstable nuclei, however, with only theoretically predicted reaction rates are included in the reaction network and thus the nuclear input may also bear considerable uncertainties. The current status of astrophysical models, nuclear input and observational constraints is reviewed. After an overview of currently discussed models, the focus is on the possibility to better constrain those models through different means. Meteoritic data not only provide the actual isotopic abundances of the p-nuclei but can also put constraints on the possible contribution of proton-rich nucleosynthesis. The main part of the review focuses on the nuclear uncertainties involved in the determination of the astrophysical reaction rates required for the extended reaction networks used in nucleosynthesis studies. Experimental approaches are discussed together with their necessary connection to theory, which is especially pronounced for reactions with intermediate and heavy nuclei in explosive nuclear burning, even close to stability. © 2013 IOP Publishing Ltd.
Kiss G.G.,MTA Atomki |
Kiss G.G.,RIKEN |
Szucs T.,MTA Atomki |
Szucs T.,Helmholtz Center Dresden |
And 8 more authors.
Journal of Physics G: Nuclear and Particle Physics | Year: 2015
The γ-process in core-collapse and/or type Ia supernova explosions is thought to explain the origin of the majority of the so-called p nuclei (the 35 proton-rich isotopes between Se and Hg). Reaction rates for γ-process reaction network studies have to be predicted using Hauser-Feshbach statistical model calculations. Recent investigations have shown problems in the prediction of α-widths at astrophysical energies which are an essential input for the statistical model. It has an impact on the reliability of abundance predictions in the upper mass range of the p nuclei. With the measurement of the 164,166Er(α,n)167,169Yb reaction cross sections at energies close to the astrophysically relevant energy range we tested the recently suggested low energy modification of the α+nucleus optical potential in a mass region where γ-process calculations exhibit an underproduction of the p nuclei. Using the same optical potential for the α-width which was derived from combined 162Er(α,n) and 162Er(α,γ) measurement makes it plausible that a low-energy modification of the optical α+nucleus potential is needed. © 2015 IOP Publishing Ltd.
Spadtke P.,Helmholtz Center for Heavy Ion Research |
Lang R.,Helmholtz Center for Heavy Ion Research |
Mader J.,Helmholtz Center for Heavy Ion Research |
Maimone F.,Helmholtz Center for Heavy Ion Research |
And 4 more authors.
Review of Scientific Instruments | Year: 2016
Simulation of ion beam extraction from an Electron Cyclotron Resonance Ion Source (ECRIS) is a fully 3 dimensional problem, even if the extraction geometry has cylindrical symmetry. Because of the strong magnetic flux density, not only the electrons are magnetized but also the Larmor radius of ions is much smaller than the geometrical dimension of the plasma chamber (Ø 64 × 179 mm). If we assume that the influence of collisions is small on the path of particles, we can do particle tracking through the plasma if the initial coordinates of particles are known. We generated starting coordinates of plasma ions by simulation of the plasma electrons, accelerated stochastically by the 14.5 GHz radio frequency power fed to the plasma. With that we were able to investigate the influence of different electron energies on the extracted beam. Using these assumptions, we can reproduce the experimental results obtained 10 years ago, where we monitored the beam profile with the help of viewing targets. Additionally, methods have been developed to investigate arbitrary 2D cuts of the 6D phase space. To this date, we are able to discuss full 4D information. Currently, we extend our analysis tool towards 5D and 6D, respectively. © 2015 AIP Publishing LLC.
PubMed | University of Brighton, Institute for Nuclear Science & Technology, University of Oslo, Tohoku University and 9 more.
Type: Journal Article | Journal: Physical review letters | Year: 2015
We report on the measurement of the first 2(+) and 4(+) states of (66)Cr and (70,72)Fe via in-beam -ray spectroscopy. The nuclei of interest were produced by (p,2p) reactions at incident energies of 260MeV/nucleon. The experiment was performed at the Radioactive Isotope Beam Factory, RIKEN, using the DALI 2-ray detector array and the novel MINOS device, a thick liquid hydrogen target combined with a vertex tracker. A low-energy plateau of 2(1)(+) and 4(1)(+) energies as a function of the neutron number was observed for N38 and N40 for even-even Cr and Fe isotopes, respectively. State-of-the-art shell model calculations with a modified Lenzi-Nowacki-Poves-Sieja (LNPS) interaction in the pfg(9/2)d(5/2) valence space reproduce the observations. Interpretation within the shell model shows an extension of the island of inversion at N=40 for more neutron-rich isotopes towards N=50.
PubMed | University of Pannonia, Hungarian Academy of Sciences and MTA Atomki
Type: Journal Article | Journal: Electrophoresis | Year: 2016
Design, fabrication, integration, and feasibility test results of a novel microfluidic cell capture device is presented, exploiting the advantages of proton beam writing to make lithographic irradiations under multiple target tilting angles and UV lithography to easily reproduce large area structures. A cell capture device is demonstrated with a unique doubly tilted micropillar array design for cell manipulation in microfluidic applications. Tilting the pillars increased their functional surface, therefore, enhanced fluidic interaction when special bioaffinity coating was used, and improved fluid dynamic behavior regarding cell culture injection. The proposed microstructures were capable to support adequate distribution of body fluids, such as blood, spinal fluid, etc., between the inlet and outlet of the microfluidic sample reservoirs, offering advanced cell capture capability on the functionalized surfaces. The hydrodynamic characteristics of the microfluidic systems were tested with yeast cells (similar size as red blood cells) for efficient capture.
Mathe D.,med Research Centers Ltd. |
Szigeti K.,Semmelweis University |
Hegedus N.,Semmelweis University |
Horvath I.,Semmelweis University |
And 3 more authors.
Applied Radiation and Isotopes | Year: 2016
212Pb is a clinically relevant therapeutic alpha emitter isotope. A surrogate, 203Pb, if prepared with sufficiently high specific activity could be used to estimate 212Pb in vivo absorbed doses. An improved production procedure of 203Pb with a simple, new separation method and high specific radioactivity for imaging is reported. We determined the in-vivo biodistribution of 203Pb in mice by SPECT/CT. This highlights application possibilities of 203Pb for further in vivo and clinical uses (radiolabeled 212Pb-peptide co-injection, dosimetry calculation). © 2016 Elsevier Ltd.
PubMed | MTA Atomki, Semmelweis University, med Research Centers Ltd. and Debrecen University
Type: | Journal: Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine | Year: 2016
(212)Pb is a clinically relevant therapeutic alpha emitter isotope. A surrogate, (203)Pb, if prepared with sufficiently high specific activity could be used to estimate (212)Pb in vivo absorbed doses. An improved production procedure of (203)Pb with a simple, new separation method and high specific radioactivity for imaging is reported. We determined the in-vivo biodistribution of (203)Pb in mice by SPECT/CT. This highlights application possibilities of (203)Pb for further in vivo and clinical uses (radiolabeled (212)Pb-peptide co-injection, dosimetry calculation).
Soki E.,Debrecen University |
Csige I.,MTA Atomki
Nukleonika | Year: 2016
The final product of a post-volcanic activity is the exhalation of low-temperature (<100°C) gases containing mostly carbon dioxide. The phenomenon is called mofettes, which are often used for therapeutic treatments in the form of dry CO2 spas. Along its pathway to the surface, the deep origin gas also intakes different radon isotopes from the rocks and soils; therefore, the risks associated with radon exposures should also be a concern. In this work, we have found that the 222Rn activity concentration in the mofette gas of Mátraderecske is particularly high; it is in the order of 200 kBq·m-3. However, owing to the carefully designed flow pattern of mofette gas and fresh air, the radon level is about 1 kBq·m-3 at the breath level of the staff, accompanying the treatment, which is the radon reference level for workers in Hungary. We have also found that in this dry spa, radon is a good tracer of CO2; therefore, it can be used to monitor the CO2 distribution in the treatment pools.
Fulop Z.,MTA Atomki |
Levai G.,MTA Atomki
Nuclear Physics News | Year: 2015
Some twenty minutes’ walk from the center of Debrecen, Hungary’s second largest city, there stands a complex of three two-storeyed red-brick buildings. Originally serving as an orphanage of the reformed church of Hungary, the buildings now have a rather different role: two of them house the physics departments of the University of Debrecen, while the third one is where Atomki, the Institute for Nuclear Research of the Hungarian Academy of Sciences (MTA) was founded in 1954, and where its offices and some of its laboratories are still located. Anyone passing by is reminded of these times by the 800 kV cascade generator, which peacefully rests in the garden after being decommissioned in 1992. But it is not the only reminder there of the historic times. © 2015, Taylor & Francis.
Betak E.,Slovak Academy of Sciences |
Cseh J.,MTA ATOMKI
Proceedings of the 14th International Conference on Nuclear Reaction Mechanisms, NRM 2015 | Year: 2015
We bring the possibility to include the cluster emission into the statistical pre-equilibrium (exciton) model enlarged for considering also the heavy ion collisions. At this moment, the calculations have been done without treatment of angular momentum variables, but all the approach can be straightforwardly applied to heavy-ion reactions with cluster emission including the angular momentum variables. The direct motivation of this paper is a possibility of producing the superdeformed nuclei, which are easier to be detected in heavy-ion reactions than in those induced by light projectiles (nucleons, deuterons, α-particles). © 2015, CERN. All rights reserved.