Search results for "hell"

Structure of the As, Ge, Ga nuclei

2012

Abstract The level structures of the N = 50 83As, 82Ge, and 81Ga isotones have been investigated by means of multi-nucleon transfer reactions. A first experiment was performed with the CLARA–PRISMA setup to identify these nuclei. A second experiment was carried out with the GASP array in order to deduce the γ-ray coincidence information. The results obtained on the high-spin states of such nuclei are used to test the stability of the N = 50 shell closure in the region of 78Ni ( Z = 28 ). The comparison of the experimental level schemes with the shell-model calculations yields an N = 50 energy gap value of 4.7(3) MeV at Z = 28 . This value, in a good agreement with the prediction of the fini…

Collective 2$^{+1}$ excitations in$^{206}$Po and$^{208,210}$Rn

2016

In the present study, $B(E2; 2^{+}_{1}\rightarrow 0^{+}_{1})$ values have been measured in the 208,210Rn and 206Po nuclei through Coulomb excitation of re-accelerated radioactive beams in inverse kinematics at CERN-ISOLDE. These nuclei have been proposed to lie in, or at the boundary of the region where the seniority scheme should persist. However, contributions from collective excitations are likely to be present when moving away from the N=126 closed shell. Such an effect is confirmed by the observed increased collectivity of the $2^{+}_{1}\rightarrow 0^{+}_{1}$ transitions. Experimental results have been interpreted with the aid of theoretical studies carried out within the BCS-based QRP…

Spectroscopy of34,35Sibyβdecay:sd−fpshell gap and single-particle states

2001

Medium-spin levels and the character of the 20.4 ns isomer in 145Gd

1982

Abstract Levels of the N = 81 nucleus 145Gd have been investigated by in-beam γ-ray and conversion electron spectroscopy with the 144Sm(3He, 2n) reaction. Fourteen new low- and medium-spin states between 1.0 and 2.4 MeV excitation, the known yrast levels up to spin 21 2 + , five other high-spin non-yrast states and a new 20.4 ns 13 2 isomer at 2200.2 keV in 145Gd have been observed. The isomer decays via a fast 927.3 keV E3 transition with B(E3) = 48 ± 7 W.u. Another weaker decay branch is a mixed, strongly hindered E1 + M2 + E3 transition to the v h −1 11 2 state. We propose an octupole v f 7 2 j −2 × 3 − main configuration for the isomer, analogous to the 997 keV 13 2 + isomer in 147Gd. T…

Proton Inelastic Scattering onNi56in Inverse Kinematics

1994

Inelastic proton scattering to the first excited ${2}^{+}$ state of the doubly magic $^{56}\mathrm{Ni}$ nucleus was investigated in inverse kinematics, using a secondary beam of radioactive $^{56}\mathrm{Ni}$ nuclei. At an incident energy of 101 MeV/nucleon, a value $B(E2,{0}^{+}\ensuremath{\rightarrow}{2}^{+})=600\ifmmode\pm\else\textpm\fi{}120 {e}^{2}$ ${\mathrm{fm}}^{4}$ was measured. This result completes the set of experimental data for the first excited ${2}^{+}$ states in the $1f\ensuremath{-}2p$ shell with a closed shell of neutrons or protons. These data are compared to recent shell-model calculations.

Shell-model study on event rates of lightest supersymmetric particles scattering offKr83andTe125

2016

We investigate the elastic and inelastic scattering of lightest supersymmetric particle (LSP) dark matter off two possible target nuclei, $^{83}\mathrm{Kr}$ and $^{125}\mathrm{Te}$. For the nuclear-structure calculations, we employ the nuclear shell model using recently generated realistic interactions. We have condensed the nuclear-physics contribution to a set of nuclear-structure factors that are independent of the adopted supersymmetric (SUSY) model. Total event rates are then easily calculated by combining the nuclear-structure factors with SUSY parameters of choice. In particular, $^{125}\mathrm{Te}$ shows promise as a detector material with both the elastic and inelastic channels yie…

Equivalence between local Fermi gas and shell models in inclusive muon capture from nuclei

2005

Motivated by recent studies of inclusive neutrino nucleus processes and muon capture within a correlated local Fermi gas model (LFG), we discuss the relevance of nuclear finite size effects in these reactions at low energy, in particular for muon capture. To disentangle these effects from others coming from the reaction dynamics we employ here a simple uncorrelated shell model that embodies the typical finite size content of the problem. The integrated decay widths of muon atoms calculated with this shell model are then compared for several nuclei with those obtained within the uncorrelated LFG, using in both models exactly the same theoretical ingredients and parameters. We find that the t…

Positron Production In Heavy-Ion Collisions

1985

Atomic systems with a nuclear charge Z much greater than 100 exhibit a number of unique features not otherwise found in nature. Two characteristic properties are illustrated in Figs. 1 and 2. In Fig. 1 we have plotted the binding energy of a K-shell electron around hypothetical nuclei up to Z ≈ 200. For Z > 150 the binding energy exceeds the rest energy m e c 2 of the electron; i.e., adding the electron to the nucleus actually diminishes the total mass of the system. At the critical charge Z c ≈ 170–175 the binding energy reaches twice the electron rest mass, the threshold for spontaneous creation of an electron-positron pair. As has been discussed extensively in the literature (Pieper and …

Quantum-state-selective decay spectroscopy of Ra213

2017

An experimental scheme combining the mass resolving power of a Penning trap with contemporary decay spectroscopy has been established at GSI Darmstadt. The Universal Linear Accelerator (UNILAC) at GSI Darmstadt provided a $^{48}\mathrm{Ca}$ beam impinging on a thin $^{170}\mathrm{Er}$ target foil. Subsequent to velocity filtering of reaction products in the Separator for Heavy Ion reaction Products (SHIP), the nuclear ground state of the $5n$ evaporation channel $^{213}\mathrm{Ra}$ was mass-selected in SHIPTRAP, and the $^{213}\mathrm{Ra}$ ions were finally transferred into an array of silicon strip detectors surrounded by large composite germanium detectors. Based on comprehensive geant4 s…

On the SN 1993J Radio Shell Structure

2005

An accurate measurement of the expansion deceleration of SN 1993J depends on how well the shell size and its emission structure are known. With the goal of determining the emission structure of the shell, we have developed a new approach, which we call “Green Function Deconvolution” (GFD), based on iterative use of Green functions on the sky plane to reconstruct the radial emission profiles of spherically symmetric sources. This approach works reasonably well in the case of optically thin emitting sources, which is not the case for SN 1993J since, as we find, the emission from the central part of SN 1993J further away from us is strongly or totally absorbed. We describe the GFD method and p…