On the stability of superheavy nuclei

The European Physical Journal A - The Dynamical Cluster-decay Model (DCM) has been employed to analyze the charge particle emission from $$^{207, 209}$$ Pb $$^*$$ isotopes formed in highly...     

Atom Trap Trace Analysis of Ca Isotopes

In our experiment we aim at the detection of the rarest, naturally occuring calcium isotope Ca by means of atom trap trace analysis. On basis of single-atom detection of Ca our present sensitivity for Ca is estimated to be 1 atom per hour at an abundance of 10. To reach a sensitivity at the level of natural abundance, which is 10, we need to reduce atomic beam losses. To achieve this, optical compression of the atomic beam is a promising option. We use Monte Carlo Simulations to demonstrate that optical compression of the atomic beam increases throughput of the atomic beam as well as isotope selectivity.     

Measurement of the $$^{232}$$ Th(n,f) cross section with quasi-monoenergetic neutron beams in the energy range 2–18 MeV

The European Physical Journal A - The E1 contribution to the capture reaction $$^7\mathrm {Li}(n,\gamma )^8\mathrm {Li}$$  is calculated at low energies. We employ a coupled-channel...     

Extraction of proton trace anomaly energy from near-threshold $$\phi $$ and $$J/\psi $$ photo-productions

The European Physical Journal A - We discuss a phenomenological shell model analysis of the structure of $$^{48,49,50}$$ Ca. Based on simple arguments, we propose wavefunctions fit to the available...     

Vortex–shock and vortex–vortex interactions in the compressible starting jet from two beveled nozzle configurations

Journal of Visualization - An experiment was conducted to investigate the flow structures in the compressible starting jet from two beveled nozzles (45 $$^{\circ }$$ and 30 $$^{\circ }$$ nozzle...     

Parity Violation in the Scattering of a Proton by Carbon and Oxygen

JETP Letters - The effects of parity violation in the interaction of relativistic polarized protons with $$^{{12}}{\text{C}}$$ and $$^{{16}}{\text{O}}$$ nuclei are discussed. Within the Glauber...     

Simulating the Detection of Hidden Explosives with Photonuclear Techniques

Physics of Particles and Nuclei Letters - Detecting explosives hidden in luggage by the beta activity of $$^{{12}}{\text{B}}$$ generated through the reaction $$^{{13}}{\text{C}}{{(\gamma...     

Ion Mobility Measurements and Ion Chemical Reaction Studies at Heavy Elements in a Buffer Gas Cell

Drift time measurements of ions in a buffer gas cell filled with argon have been performed from which changes of the ion mobility and ionic radii for various heavy elements and their compounds were determined. The ionic radius of americium shrinks by (3.1 1.3)% with respect to that of plutonium, and an increase of the radius by (28 2)% of plutonium oxide with respect to plutonium was found. Ion chemical reactions of erbium ions were studied online in an argon buffer gas cell to which the reaction gases oxygen (O) and methane (CH) were added. The erbium ions were implanted into the buffer gas cell with an energy of 50 MeV. The online measured reaction constant = (3.2 0.4) 10 cm/(molecule s) for the reaction Er + O ErO + O agrees with a reference measurement = (3.6 0.4) 10 cm/(molecule s), performed with a Fourier-Transform-Mass-Spectrometer.     

Er-Yb Codoped Ferroelectrics for Controlling Visible Upconversion Emissions

Under a 980 nm laser pumping, quenching of green upconversion (UC) emission accompanied with enhancement of red UC emission observed was dominated by the energy back-transfer (EBT) process in Er³⁺ and Yb³⁺ co-doped PbTiO₃, BaTiO₃, and SrTiO₃ polycrystalline powders. The efficiency of the EBT process depends not only on Yb³⁺ concentration but also on level match of the doped Er³⁺ and Yb³⁺ ions caused by the crystal fields with different symmetries. Our UC emission spectra and X-ray diffraction confirm that the centrosymmetric crystal field arising from reducing tetragonality causes level match of transition of Er³⁺ and of Yb³⁺. This level match is responsible for enhancing red UC emission.     

g-factors of rotational states in176Hf,177Hf,and180Hf

g-factors of rotational states in¹⁷⁶Hf and¹⁸⁰Hf were measured with the twelve detector IPAC-apparatus of our laboratory [1]. The natural radioactivity 3.78·10¹⁰y¹⁷⁶Lu and the 5.5 h isomer^180mHf were used which populate the ground-state rotational bands of¹⁷⁶Hf and¹⁸⁰Hf. The integral rotations ofγ-γ directional correlations in strong external magnetic fields and in static hyperfine fields of (Lu→Hf)Fe₂ and HfFe₂ were observed. The following results were obtained: $$\begin{array}{l} ^{176} Hf: g\left( {4_1^ + } \right) = + 0.334\left( {38} \right) \\ ^{180} Hf: g\left( {2_1^ + } \right) = + 0.305\left( {14} \right) \\ g\left( {4_1^ + } \right) = + 0.358\left( {43} \right) \\ {{ g\left( {6_1^ + } \right)} \mathord{\left/ {\vphantom {{ g\left( {6_1^ + } \right)} {g\left( {4_1^ + } \right)}}} \right. \kern-\nulldelimiterspace} {g\left( {4_1^ + } \right)}} = + 0.95\left( {12} \right) \\ \end{array}$$ . The hyperfine field in (Lu→Hf)Fe₂ was calibrated by observing the integral rotation of the 9/2^? first excited state of¹⁷⁷Hf populated in the decay of 6.7d¹⁷⁷Lu. Theg-factor of this state was redetermined in an external magnetic field as $$^{177} Hf: g\left( {{9 \mathord{\left/ {\vphantom {9 {2^ - }}} \right. \kern-\nulldelimiterspace} {2^ - }}} \right) = + 0.228\left( 7 \right)$$ . Finally theg-factor of the 2 ₁ ⁺ state of¹⁷⁶Hf was derived from the measuredg(2 ₁ ⁺ ) of¹⁸⁰Hf by use of the precisely known ratiog(2 ₁ ⁺ ,¹⁷⁶Hf)/g(2 ₁ ⁺ ,¹⁸⁰Hf) [2] as $$^{176} Hf: g\left( {2_1^ + } \right) = + 0.315\left( {30} \right)$$ .     

Systematic Low-Energy Optical Model Potential for $$\alpha$$ -Nucleus Elastic Scattering

Physics of Atomic Nuclei - The elastic scattering of $$\alpha$$ particle from $${}^{89}$$ Y, $${}^{92}$$ Mo, $${}^{106-116}$$ Cd, $${}^{112}$$ Sn, and $${}^{144}$$ Sm nuclei ( $$Z=39{-}62$$ ) at...     

Microscopic Analysis of Elastic Scattering Angular Distributions for Five Different Density Distribution of 9Be Nucleus

Physics of Atomic Nuclei - The elastic scattering angular distributions of the weakly bound $${}^{9}$$ Be projectile by $${}^{27}$$ Al, $${}^{64}$$ Zn, $${}^{89}$$ Y, $${}^{120}$$ Sn, and...     

Systematic Approach to Calculate the Total Kinetic Energy Distribution of Actinides for the Photofission Phenomenon

Physics of Atomic Nuclei - The total kinetic energy as a function of fragment mass (TKE/A) was calculated for photofission of $${}^{232}$$ Th, $${}^{234}$$ U, $${}^{238}$$ U, $${}^{240}$$ Pu, and...     

Emission of High-Energy Alpha Particles in the Interaction of $${}^{48}$$ Ca Nuclei with Tantalum,Gold, and Uranium Nuclei at 280 MeV

Physics of Atomic Nuclei - The energy spectra of alpha particles from reactions induced by 280-MeV $${}^{48}$$ Ca beams incident to $${}^{181}$$ Ta, $${}^{197}$$ Au, and $${}^{238}$$ U targets were...     

Comparing a New Optimized Potential with Woods–Saxon Potential in Heavy-Ion Reactions $${}^{{28}}$$ Si, $${}^{{32,36}}$$ S, $${}^{{40,48}}$$ Ca, $${}^{{46,50}}\textrm{Ti}{+}^{{90}}$$ Zr

Physics of Atomic Nuclei - This study analyzed the fusions of zirconium with projectiles $${}^{28}$$ Si, $${}^{32,36}$$ S, $${}^{40,48}$$ Ca, $${}^{46,50}$$ Ti by using the CCFULL code. The...     

Hopf Bifurcations,Drops in the Lid-Driven Square Cavity Flow

The lid-driven square cavity flow is investigated by numerical experiments. It is found that from $ \mathrm{Re} $$=$ $5,000 $ to $ \mathrm{Re} $$=$$ 7,307.75 $ the solution is stationary, but at $ \mathrm{Re}$$=$$7,308 $ the solution is time periodic. So the critical Reynolds number for the first Hopf bifurcation localizes between $ \mathrm{Re} $$=$$ 7,307.75 $ and $ \mathrm{Re} $$=$$ 7,308 $. Time periodical behavior begins smoothly, imperceptibly at the bottom left corner at a tiny tertiary vortex; all other vortices stay still, and then it spreads to the three relevant corners of the square cavity so that all small vortices at all levels move periodically. The primary vortex stays still. At $ \mathrm{Re} $$=$$ 13,393.5 $ the solution is time periodic; the long-term integration carried out past $ t_{\infty} $$=$$ 126,562.5 $ and the fluctuations of the kinetic energy look periodic except slight defects. However, at $ \mathrm{Re} $$=$$ 13,393.75 $ the solution is not time periodic anymore: losing unambiguously, abruptly time periodicity, it becomes chaotic. So the critical Reynolds number for the second Hopf bifurcation localizes between $ \mathrm{Re} $$=$$ 13,393.5 $ and $ \mathrm{Re} $$=$$ 13,393.75 $. At high Reynolds numbers $ \mathrm{Re} $$=$$ 20,000 $ until $ \mathrm{Re} $$=$$ 30,000 $ the solution becomes chaotic. The long-term integration is carried out past the long time $ t_{\infty} $$=$$ 150,000 $, expecting the time asymptotic regime of the flow has been reached. The distinctive feature of the flow is then the appearance of drops: tiny portions of fluid produced by splitting of a secondary vortex, becoming loose and then fading away or being absorbed by another secondary vortex promptly. At $ \mathrm{Re} $$=$$ 30,000 $ another phenomenon arises—the abrupt appearance at the bottom left corner of a tiny secondary vortex, not produced by splitting of a secondary vortex.     

Perchlorate Reduction by Nanoscale Iron Particles

We report herein the near complete reduction of perchlorate (ClO ) to chloride by nanoscale iron particles. The nanoparticles also reduce chlorate (ClO ), chlorite (ClO ) and hypochlorite (ClO ) to chloride. No reaction was observed with microscale iron powder under identical conditions. The temperature sensitivity of the perchlorate-nanoparticle reaction is evidenced by progressively increasing rate constant values of 0.013, 0.10, 0.64 and 1.52 mg perchlorate per g nanoparticles per hour (mg-g^-1-hr^-1), respectively, at temperatures of 25, 40, 60 and 75°C. The activation energy of perchlorate-iron reaction was calculated to be 79.02 ± 7.75 kJ/mole. Despite favorable thermodynamics, the relatively large activation energy for this reaction suggests that perchlorate reduction is limited by the slow kinetics. The nanoscale iron particles may represent a potential treatment method for perchlorate-contaminated water.     

Mössbauer Study of Microstructure and Magnetic Properties (Co,Ni)–Zr Substituted Ba Ferrite Particles

The β-NMR of short-lived β-emitter in a rutile TiO₂ single crystal has been measured as functions of temperature and external magnetic field. Atomic motion induced spin lattice relaxation was observed for two known sites, O substitutional and interstitial sites. The data were analyzed in terms of the thermal atomic jump, which suggests that the motion of defects around the substitutional ¹²N atom for O, and of the interstitial ¹²N atom are attributed to the spin lattice relaxation. The electric field gradients have shown temperature dependence for both sites, which is probably due to the thermal expansion of rutile.     

Gyromagnetic ratio of the 2+ rotational state of184W and observation of a large hyperfine anomaly with respect to183Wg in iron

Theg-factor of the 2⁺ rotational state of¹⁸⁴W was redetermined by an IPAC measurement in an external magnetic field of 9.45 (5)T as: $$g_{2^ + } (^{184} W) = + 0.289(7).$$ In the evaluation the remeasured half-life of the 2⁺ state: $$T_{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} (2^ + ) = 1.251(12)ns$$ was used. TDPAC-measurements with a sample of carrierfree¹⁸⁴Re in high purity iron gave the hyperfine fields: $$B_{300 K}^{hf} (^{184} W_2 + \underline {Fe} ) = 70.1(21)T$$ and $$B_{40 K}^{hf} (^{184} W_{2^ + } \underline {Fe} ) = 71.8(22)T.$$ A comparison with the hyperfine field known from a spin echo experiment with¹⁸³W _g Fe leads to the hyperfine anomaly: $$^{184} W_{2^ + } \Delta ^{183} W_g = + 0.145(36).$$ The hyperfine splitting observed in a Mössbauer source experiment with another sample of carrierfree^184m Re in high purity iron indicates that the smaller splitting, measured previously by a Mössbauer absorber experiment is due to the high tungsten concentration in the absorber. The new value for theg-factor of the 2⁺ state together with the result of the Mössbauer experiment allow an improved calibration for our recent investigation of theg _R -factors of the 4⁺ and 6⁺ rotational states. The recalculated values are: $$g_{4^ + } (^{184} W) = + 0.293(23)$$ and $$g_{6^ + } (^{184} W) = + 0.299(43).$$ The remeasured 792-111 keVγ-γ angular correlation $$W(\Theta ) = 1 - 0.034(4) \cdot P_2 + 0.325(6) \cdot P_4 $$ gives for the mixing ratio of theK-forbidden 792keV transition: $$\delta ({{E2} \mathord{\left/ {\vphantom {{E2} {M1}}} \right. \kern-\nulldelimiterspace} {M1}}) = - \left( {17.6\begin{array}{*{20}c} { + 1.8} \\ { - 1.5} \\ \end{array} } \right).$$ A detailed investigation of the attenuation ofγ-γ angular correlations in liquid sources of¹⁸⁴Re and^184m Re revealed the reason for erroneous results of early measurements of the 2⁺ g _R -factor: The time dependence of the perturbation is not of a simple exponential type. It contains an unresolved strong fast component.     

Search for Scalar Resonance in the ωϕ System in the Pion-Nuclear Interaction at Momentum of 29 GeV/c

Physics of Atomic Nuclei - The charge-exchange reaction $${{\pi }^{ - }}p \to n\omega (783)\phi (1020)$$ , $$\omega \to {{\pi }^{ + }}{{\pi }^{ - }}{{\pi }^{0}}$$ , $$\phi \to {{K}^{ + }}{{K}^{ -...