F. Strieder
A5062715072- Nuclear physics research studies
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- Neutrino Physics Research
- Astronomical and nuclear sciences
- Advanced Chemical Physics Studies
- Gamma-ray bursts and supernovae
- Particle physics theoretical and experimental studies
- X-ray Spectroscopy and Fluorescence Analysis
- Astro and Planetary Science
- Particle accelerators and beam dynamics
- Quantum, superfluid, helium dynamics
- Quantum Chromodynamics and Particle Interactions
- Nuclear reactor physics and engineering
- Superconducting Materials and Applications
- Advanced NMR Techniques and Applications
- Atomic and Subatomic Physics Research
- Radioactive Decay and Measurement Techniques
- Radiation Detection and Scintillator Technologies
- Atmospheric Ozone and Climate
- Dark Matter and Cosmic Phenomena
- Cold Fusion and Nuclear Reactions
- Stellar, planetary, and galactic studies
- Inorganic Fluorides and Related Compounds
- Ion-surface interactions and analysis
South Dakota School of Mines and Technology
2015-2023
HUN-REN Institute for Nuclear Research
2006-2019
Gran Sasso Science Institute
2019
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Gran Sasso
2019
Istituto Nazionale di Fisica Nucleare
2019
Ruhr University Bochum
2007-2016
University of Maryland, Baltimore
2016
University of Notre Dame
2014
Joint Institute for Nuclear Astrophysics
2014
University of Campania "Luigi Vanvitelli"
2014
The available data on nuclear fusion cross sections important to energy generation in the Sun and other hydrogen-burning stars solar neutrino production are summarized critically evaluated. Recommended values uncertainties provided for key sections, a recommended spectrum is given $^{8}\mathrm{B}$ neutrinos. Opportunities further increasing precision of rates also discussed, including new facilities, experimental techniques, improvements theory. This review, which summarizes conclusions...
We report on a new measurement of the 14N(p,γ)15O capture cross section at Ep=140 to 400 keV using kV LUNA accelerator facility Laboratori Nazionali del Gran Sasso (LNGS). The uncertainties have been reduced with respect previous measurements and their analysis. analyzed data R-matrix method we find that ground state transition accounts for about 15% total S-factor. main contribution S-factor is given by 6.79 MeV state. S(0)=1.7±0.2 b, in agreement recent extrapolations. result has important...
The fusion reactions $^{12}\mathrm{C}(^{12}\mathrm{C},\ensuremath{\alpha})^{20}\mathrm{Ne}$ and $^{12}\mathrm{C}(^{12}\mathrm{C},p)^{23}\mathrm{Na}$ have been studied from $E=2.10$ to 4.75 MeV by $\ensuremath{\gamma}$-ray spectroscopy using a C target with ultralow hydrogen contamination. deduced astrophysical $S(E{)}^{*}$ factor exhibits new resonances at $E\ensuremath{\le}3.0\text{ }\text{ }\mathrm{MeV}$, in particular, strong resonance $E=2.14\text{ which lies the high-energy tail of...
We give the LUNA results on cross section measurement of a key reaction proton-proton chain strongly affecting calculated neutrino luminosity from Sun: He3+He3-->He4+2p. Due to cosmic ray suppression provided by Gran Sasso underground laboratory it has been possible measure down lower edge solar Gamow peak, i.e. as low 16.5 keV centre mass energy. The data clearly show increase due electron screening effect but they do not exhibit any evidence for narrow resonance suggested explain observed flux.
The transition between the Main Sequence and Red Giant Branch in low mass stars is powered by onset of CNO burning, whose bottleneck 14N(p, O. LUNA collaboration has recently improved energy measurements cross section this key reaction. We analyse impact revised reaction rate on estimate Globular Cluster ages, as derived from turnoff luminosity. found that age oldest Clusters should be increased about 0.7-1 Gyr with respect to current estimates.
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 3He(alpha,gamma)7Be reaction presently represents the largest nuclear uncertainty in predicted solar neutrino flux and has important implications on big bang nucleosynthesis, i.e., production of primordial 7Li. We present here results an experiment using recoil separator ERNA (European Recoil for Nuclear Astrophysics) to detect directly 7Be ejectiles. In addition, off-beam activation coincidence gamma-ray measurements were performed at selected energies. At energies above 1 MeV a large...
It is in the nature of astrophysics that many processes and objects one tries to understand are physically inaccessible. Thus, it important those aspects can be studied laboratory rather well understood. One such aspect nuclear fusion reactions, which at heart astrophysics. They sensitively influence nucleosynthesis elements earliest stages universe all formed thereafter, control associated energy generation, neutrino luminosity evolution stars. We review a new experimental approach for...
In stars with temperatures above 20×106K, hydrogen burning is dominated by the CNO cycle. Its rate determined slowest process, 14N(p, γ)15O reaction. Deep underground in Italy's Gran Sasso laboratory, at LUNA 400 kV accelerator, cross section of this reaction has been measured energies much lower than ever achieved before. Using a windowless gas target and 4π BGO summing detector, direct data obtained down to 70 keV, reaching value 0.24 picobarn. The Gamow peak covered experimental for...
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...
We report on the results of ${}^{3}\mathrm{He}{(}^{4}\mathrm{He}{,2p)}^{4}\mathrm{He}$ experiment at underground accelerator facility LUNA (Gran Sasso). For first time lowest projectile energies utilized for cross section measurement correspond to below center solar Gamow peak ${(E}_{0}=22 \mathrm{keV})$. The data provide no evidence existence a hypothetical resonance in energy range investigated. Although extrapolation is needed anymore (except low-energy tail peak), must be corrected...
The absolute cross section of the $^{13}$C($α$,n)$^{16}$O reaction has been measured at E$_α$ = 0.8 to 8.0 MeV with an overall accuracy 4%. precision is needed subtract reliably a background in observation geo-neutrinos, e.g. KamLAND detector.
The 21Na(p,gamma)22Mg reaction is expected to play an important role in the nucleosynthesis of 22Na oxygen-neon novae. decay leads emission a characteristic 1.275 MeV gamma-ray line. This report provides first direct measurement rate this using radioactive 21Na beam, and discusses its astrophysical implications. energy state was measured be E(c.m.)=205.7+/-0.5 keV with resonance strength omegagamma=1.03+/-0.16(stat)+/-0.14(sys) meV.
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 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,...
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...