Search results for "Scheme"

Directional correlations of some γ-ray cascades in200Hg

1971

Directional correlation functions of 10 γ-ray cascades in200Hg have been measured using a200Tl source and a Ge(Li)-NaI(Tl) coincidence spectrometer arrangement. Values of the mixing parameter δ for several transitions are determined, and the spin assignments for the following levels in200Hg are established (level energies are given in keV): 1029.4 (0+), 1254.2 (2+), 1573.7 (2+), 1593.4 (2+), 1641.5 (2+), 1730.9 (2+) and 1775.6 (3+).

Decay of 14.6 h90Nb

1975

The disintegration of 14.6 h90Nb produced by bombarding natural Zr with 13 MeV protons was investigated by methods of γ-ray spectrometry. Results from singles, coincidence and anti-Compton spectrometer measurements are reported. A decay scheme is proposed including excited states in90Zr at 1761, 2186.4, 2319.1, 2739.4, 2747.9, 3077.0, 3448.2, 3589.5, 3977.1, 4232.4, 4319.5, 4375.4, 4541.6, 5060.0, 5164.6 and 5432.9 keV. Over 10 γ-ray transitions and several levels proposed in an earlier investigation are shown to be in error.

Decay of the heaviest isotope of neodymium:154Nd

1985

The neutron-rich isotope154Nd has been separated from235U fission products with the HELIum-jet On-line mass Separator HELIOS and investigated by γ-singles, γγ- and γX-coincidence measurements. The Z- and A-assignment have been confirmed by the observation of promethium KX-rays and by the genetic relationship to the daughter product 1.7-min154Pm. A half-life of 26±2 s has been obtained for154Nd, and a partial decay scheme is proposed. A 40 s activity previously assigned to154Nd could not be confirmed.

High-precision mass measurement ofS31with the double Penning trap JYFLTRAP improves the mass value forCl32

2010

The decay of 0.57 s114Cs

1980

Fusion reactions between58Ni projectiles and58Ni target nuclei were used to produce114Cs activity, which was studied by on-line mass separation and decay spectroscopy. The obtained half-life of 0.57±0.02 s and the probability ratio of 44±3 between betadelayed proton and beta-delayed alpha emission represent data with improved precision. The absolute branching ratios for both particle decay modes were determined to be (7 ±2)×10−2 and (1.6±0.6)×10−3, respectively. These branching ratios and the shapes of particle spectra are discussed with reference to the statistical model calculations. Groundstate alpha decay of114Cs was observed with an alpha energy of 3,226±30 keV and a branching ratio of…

Neutrinoless double beta decay to excited collective 0+ states

2000

Abstract The many recently performed experiments to study the two-neutrino double beta (2 νββ ) decay to the first excited 0 + final state encourage similar experiments to be done for the neutrinoless double beta (0 νββ ) decay. Based on the accumulated theoretical and experimental information on the 2 νββ decays one could hope that the 0 νββ decay to the excited 0 + state would be very efficient in restricting the parameter space of modern particle-physics theories. In this article the 0 νββ decays of 76 Ge and 82 Se to excited collective 0 + states are studied within a realistic nuclear model. It is found that the lower limits for the half-lives of these decays are of the order of 10 27 y…

Λ Decay Induced by Two Nucleons

1995

The decay of Λ hypernuclei induced by two nucleons is revised, along with its implications in the experimental determination of the ratio of neutron- to proton-stimulated Λ decay.

Nuclear structure of (231)Ac

2008

The low-energy structure of 231Ac has been investigated by means of gamma ray spectroscopy following the beta-decay of 231Ra. Multipolarities of 28 transitions have been established by measuring conversion electrons with a mini-orange electron spectrometer. The decay scheme of 231Ra --> 231Ac has been constructed for the first time. The Advanced Time Delayed beta-gamma-gamma(t) method has been used to measure the half-lives of five levels. The moderately fast B(E1) transition rates derived suggest that the octupole effects, albeit weak, are still present in this exotic nucleus. The low-energy structure of 231 Ac has been investigated by means of γ ray spectroscopy following the β − decay of…

Nuclear structure of 131Te studied with (n,γ) and reactions

2003

Abstract The structure of 131 Te has been investigated with the 130 Te( n , γγ ) 131 Te reaction using thermal neutrons and with the 130 Te( d , p ) 131 Te reaction using polarized deuterons with energy E d =18 MeV. About 290 levels were identified in most cases including spin, parity and γ -decay. The γ -decay scheme after neutron capture is essentially complete containing about 100% of the decay of the capture state and about 100% of the population of the 11/2 − isomer and of the ground state. The scheme includes 42 primary transitions with energies between 750 keV and 2500 keV. The experimental level scheme is compared with predictions of the Interacting Boson–Fermion model (IBFM) and of…

Capturing Shock Reflections: An Improved Flux Formula

1996

Godunov type schemes, based on exact or approximate solutions to the Riemann problem, have proven to be an excellent tool to compute approximate solutions to hyperbolic systems of conservation laws. However, there are many instances in which a particular scheme produces inappropriate results. In this paper we consider several situations in which Roe's scheme gives incorrect results (or blows up all together) and we propose an alternative flux formula that produces numerical approximations in which the pathological behavior is either eliminated or reduced to computationally acceptable levels.