A5017662219- Nuclear physics research studies
- Nuclear Physics and Applications
- Astronomical and nuclear sciences
- Atomic and Molecular Physics
- Nuclear reactor physics and engineering
- Quantum Chromodynamics and Particle Interactions
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced NMR Techniques and Applications
- Radiation Detection and Scintillator Technologies
- Neutrino Physics Research
- Particle physics theoretical and experimental studies
- Advanced Chemical Physics Studies
- Atomic and Subatomic Physics Research
- Particle Detector Development and Performance
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Superconducting Materials and Applications
- Radiation Therapy and Dosimetry
- Inorganic Fluorides and Related Compounds
- Medical Imaging Techniques and Applications
- Gamma-ray bursts and supernovae
- Particle accelerators and beam dynamics
- Radiopharmaceutical Chemistry and Applications
- High-pressure geophysics and materials
- Dark Matter and Cosmic Phenomena
University of Debrecen
2009-2025
HUN-REN Institute for Nuclear Research
2015-2024
GSI Helmholtz Centre for Heavy Ion Research
2014-2024
Hungarian Research Network
2006-2022
Eötvös Loránd University
2022
RIKEN Nishina Center
2009-2021
Petersburg Nuclear Physics Institute
2021
Hungarian Academy of Sciences
2008-2019
Gran Sasso Science Institute
2019
Joint Institute for Nuclear Astrophysics
2019
A long-standing question in nuclear physics is whether chargeless systems can exist. To our knowledge, only neutron stars represent near-pure systems, where neutrons are squeezed together by the gravitational force to very high densities. The experimental search for isolated multi-neutron has been an ongoing quest several decades1, with a particular focus on four-neutron system called tetraneutron, resulting few indications of its existence so far2-4, leaving tetraneutron elusive six...
The energies of the excited states in very neutron-rich (42)Si and (41,43)P have been measured using in-beam gamma-ray spectroscopy from fragmentation secondary beams (42,44)S at 39A MeV. low 2(+) energy (42)Si, 770(19) keV, together with level schemes (41,43)P, provides evidence for disappearance Z=14 N=28 spherical shell closures, which is ascribed mainly to action proton-neutron tensor forces. New model calculations indicate that best described as a well-deformed oblate rotor.
Recent observations of (6)Li in metal poor stars suggest a large production this isotope during big bang nucleosynthesis (BBN). In standard BBN calculations, the (2)H(α,γ)(6)Li reaction dominates production. This has never been measured inside energy region because its cross section drops exponentially at low and electric dipole transition is strongly suppressed for isoscalar particles (2)H α energies below Coulomb barrier. Indirect measurements using dissociation only give upper limits...
Subjecting a physical system to extreme conditions is one of the means often used obtain better understanding and deeper insight into its organization structure. In case atomic nucleus, such approach investigate isotopes that have very different neutron-to-proton (N/Z) ratios than in stable nuclei. Light, neutron-rich exhibit most asymmetric N/Z those lying beyond limits binding, which undergo spontaneous neutron emission exist only as short-lived resonances (about 10-21 s), provide...
The nuclear physics input from the He3(α,γ)Be7 cross section is a major uncertainty in fluxes of Be7 and B8 neutrinos Sun predicted by solar models Li7 abundance obtained big-bang nucleosynthesis calculations. present work reports on new precision experiment using activation technique at energies directly relevant to nucleosynthesis. Previously such low had been reached experimentally only prompt-γ with inferior precision. Using windowless gas target, high beam intensity, background...
Solar neutrino fluxes depend both on astrophysical and nuclear physics inputs, namely the cross sections of reactions responsible for production inside core. While flux solar $^{8}\mathrm{B}$ neutrinos has been recently measured at Superkamiokande with a 3.5% uncertainty precise measurement $^{7}\mathrm{Be}$ is foreseen in next future, predicted are still affected by larger errors. The largest to determine comes from...
The very neutron-rich oxygen isotopes ${}^{25}$O and ${}^{26}$O are investigated experimentally theoretically. unbound states populated in an experiment performed at the R3B-LAND setup GSI via proton-knockout reactions from ${}^{26}$F ${}^{27}$F relativistic energies around 442 414 MeV/nucleon, respectively. From kinematically complete measurement of decay into ${}^{24}$O plus one or two neutrons, ground-state energy width determined, upper limits for lifetime extracted. In addition, results...
Quasifree one-proton knockout reactions have been employed in inverse kinematics for a systematic study of the structure stable and exotic oxygen isotopes at ${\mathrm{R}}^{3}\mathrm{B}/\mathrm{LAND}$ setup with incident beam energies range $300--450\text{ }\mathrm{MeV}/\mathrm{u}$. The isotopic chain offers large variation separation that allows quantitative understanding single-particle strength changing isospin asymmetry. provide complementary approach to intermediate-energy one-nucleon...
The ^{17}O(p,α)^{14}N reaction plays a key role in various astrophysical scenarios, from asymptotic giant branch stars to classical novae. It affects the synthesis of rare isotopes such as ^{17}O and ^{18}F, which can provide constraints on models. A new direct determination E_{R}=64.5 keV resonance strength performed at Laboratory for Underground Nuclear Astrophysics (LUNA) accelerator has led most accurate value date ωγ=10.0±1.4_{stat}±0.7_{syst} neV, thanks significant background...
The Ne22(p,γ)Na23 reaction takes part in the neon-sodium cycle of hydrogen burning. This affects synthesis elements between Ne20 and Al27 asymptotic giant branch stars novae. rate is very uncertain because a large number unobserved resonances lying Gamow window. At proton energies below 400 keV, only upper limits exist literature for resonance strengths. Previous evaluations differ by factors. In present work, first direct observations at 156.2, 189.5, 259.7 keV are reported. Their strengths...
One of the main neutron sources for astrophysical s process is reaction ^{13}C(α,n)^{16}O, taking place in thermally pulsing asymptotic giant branch stars at temperatures around 90 MK. To model nucleosynthesis during this cross section needs to be known 150-230 keV energy window (Gamow peak). At these sub-Coulomb energies, direct measurements are severely affected by low event rate, making us rely on input from indirect methods and extrapolations higher-energy data. This leads an uncertainty...
Abstract Studies of charged-particle reactions for low-energy nuclear astrophysics require high sensitivity, which can be achieved by means detection setups with efficiency and low backgrounds, to obtain precise measurements in the energy region interest stellar scenarios. High-efficiency total absorption spectroscopy is an established powerful tool studying radiative capture reactions, particularly if combined cosmic background reduction several orders magnitude obtained at Laboratory...
The C12/C13 ratio is a significant indicator of nucleosynthesis and mixing processes during hydrogen burning in stars. Its value mainly depends on the relative rates C12(p,γ)N13 C13(p,γ)N14 reactions. Both reactions have been studied at Laboratory for Underground Nuclear Astrophysics (LUNA) Italy down to lowest energies date (Ec.m.=60 keV) reaching first time high energy tail shell giant Our cross sections, obtained with both prompt γ-ray detection activation measurements, are most precise...
The electric quadrupole transition from the first 2(+) state to ground 0(+) in 16C is studied through measurement of lifetime by a recoil shadow method applied inelastically scattered radioactive nuclei. measured mean 77+/-14(stat)+/-19(syst) ps. central value corresponds B(E2;2+(1)-->0(+)) 0.63e(2) fm(4), or 0.26 Weisskopf units. strength found be anomalously small compared empirically predicted value.
The flux of Be7 and B8 neutrinos from the Sun production Li7 via primordial nucleosynthesis depend on rate He3(α,γ)Be7 reaction. In an extension a previous study showing cross section data at 127–167 keV center-of-mass energy, present work reports measurement 106 performed Italy's Gran Sasso underground laboratory by activation method. This energy is closer to solar Gamow than ever reached before. result σ=0.567±0.029stat±0.016syst nb. are compared with studies high recommended S(0) value...
The structure of 617−20C nuclei was investigated by means the in-beam γ-ray spectroscopy technique using fragmentation reactions radioactive beams. Based on particle-γ and particle-γγ coincidence data, level schemes are constructed for neutron-rich C17−20 nuclei. systematics first excited 2+ states in carbon isotopes is extended time to A=20 showing that contrast case oxygen isotopes, N=14 subshell closure disappears. Experimental results compared with shell-model calculations. Agreement...
The rate of the hydrogen-burning carbon-nitrogen-oxygen (CNO) cycle is controlled by slowest process, 14N(p,γ)15O, which proceeds capture to ground and several excited states in O15. Previous extrapolations for state contribution disagreed a factor 2, corresponding 15% uncertainty total astrophysical S factor. At Laboratory Underground Nuclear Astrophysics (LUNA) 400 kV accelerator placed deep underground Gran Sasso facility Italy, new experiment on has been carried out at 317.8, 334.4,...
Neutron single particle energies have been measured in 23O using the 22O(d,p)23O*-->22O+n process. The of resonant states deduced to be 4.00(2) MeV and 5.30(4) MeV. first excited state can assigned nu d3/2 from a comparison with shell model calculations. 4.0 energy difference between s1/2 gives size N=16 gap which is agreement recent USD05 ("universal" sd 2005) calculation, large enough explain unbound nature oxygen isotopes heavier than A=24. resonance detected at 5.3 out space. Its...
Background: The O17(p,γ)F18 reaction affects the production of key isotopes (e.g., F18 and O18) in explosive hydrogen burning that powers classical novae. Under these conditions, rate is dominated by contributions from a narrow resonance at Ec.m.=183keV combined direct capture low-energy tails broad resonances. At present, astrophysical not well constrained because lack data energy region appropriate to Purpose: This study aims measurement cross section order determine its temperature...
Proton captures on Mg isotopes play an important role in the Mg–Al cycle active stellar H-burning regions. In particular, low-energy nuclear resonances 25Mg(p, γ)26Al reaction affect production of radioactive 26Algs as well resulting Mg/Al abundance ratio. Reliable estimations these quantities require precise measurements strengths resonances. Based a new experimental study performed at Laboratory for Underground Nuclear Astrophysics, we provide revised rates γ)26Algs and γ)26Alm reactions...