Search results for "Internal conversion"
showing 10 items of 58 documents
Is the single-state dominance realized in double-β-decay transitions?
1998
In the single-state-dominance hypothesis (SSDH) the decay rate of the two-neutrino double-\ensuremath{\beta} decay to the final ground state is solely determined by virtual single-\ensuremath{\beta}-decay transitions via the ${1}^{+}$ ground state of the intermediate nucleus. A very important consequence the SSDH will be that some of nonaccelerator measurements of double-\ensuremath{\beta}-decay observables could be circumvented by single-\ensuremath{\beta}-decay measurements. To assess the validity of the SSDH, we have carried out a theoretical analysis of all double-\ensuremath{\beta}-decay transitions where the spin-parity of the ground-state of the intermediate nucleus is ${1}^{+}$. The…
Spin-flip? ? decay of even-even deformed nuclei110Ru and112Ru
1991
Neutron-rich nuclides110Ru and112Ru produced in symmetric fission of238U by 20 MeV protons have been studied at the IGISOL facility by means ofβ-ray,γ-ray and conversion electron spectroscopy. A total of 12 and 6γ-transitions were observed in the decays of110Ru and112Ru, respectively. Multipolarities were determined for a few transitions. The beta decay half-life was determined to be 11.6±0.6 s for110Ru and 1.75±0.07 s for112Ru. As a side product, a new value of 2.1±0.3 s for theβ half-life of the112Rh 1+ state was obtained. The decay energy measured with the plastic scintillator was 2.81 ±0.05 MeV for110Ru and 4.52 ±0.08 MeV for112Ru. The beta decay schemes of110Ru and112Ru isotopes indica…
Investigation of the decay of to excited states in
1996
The two-neutrino mode of double beta decay of is investigated both theoretically and experimentally. The calculations, using the quasiparticle random phase approximation approach, show that for the detection of transitions to the two first excited states in the daughter nuclide will be possible in the very near future. On the experimental side, new, most stringent limits on half-lives for the double beta decay of to excited states in have been obtained with a `well-type' germanium detector. They range between and years (90% CL).
Level structure of120Sn from the decay of120In and120Sb isomers
1971
Gamma rays in the decay of the 3.2 s (1+) and 44 s (4, 5+)120In isomers and the 15.9 min (1+) and 5.8 d (8−)120Sb isomers have been investigated using Ge(Li) spectrometers and prompt and delayed Ge(Li)-NaI(Tl) coincidence techniques. The constructed level scheme of120Sn contains 18 levels at the following energies (keV): 0 (0+), 1171.6 (2+), 1875.6 (0+), 2096.9 (1, 2, 3), 2160.7 (0+), 2195.0 (4+), 2284.8 (5−), 2355.6 (2+), 2421.2 (1, 2, 3), 2466.3 (4+), 2482.1 (7−), 2643.5 (4+), 3058.6 (4+), 3179.7 (4+), 3349.9 (3, 4+), 3440 (3, 4+), 3447.6 (5, 6+) and 3777 (4+). The levels are compared with the levels obtained from recent charged-particle reaction studies and the structure of120Sn is brief…
Aufbau eines automatisch arbeitenden ??2-Spektrometers und Untersuchung des Konversionslinienspektrums von In114m und ThB mit Folgeprodukten
1963
An automatically operatedπ√2 spectrometer is described. The regulated current supply is transistorized. With this spectrometer the electron spectra of In114m and of ThB with daughter products have been investigated. TheK/L ratio of the 191 keV isomeric transition in In114m was found to be 1·25±0·03, in excellent agreement with the theoretical value ofSliv andBand. In the electron spectrum of ThB and daughter products 46 lines were found betweenBϱ=1750Г cm andBϱ=10000Г cm. Some of them are new. Most important is a new weak line atBϱ=7030Г cm which fixes a new level atE=1·807 MeV in ThC′ (Po212). Simultaneously the earlier reported discrepancy between electron andγ-ray intensities for 1·8 MeV…
Radioactivity of neutron-rich oxygen fluorine and neon isotopes
1999
The $\ensuremath{\gamma}$ radiation and neutrons emitted following the $\ensuremath{\beta}$ decays of ${}^{24}\mathrm{O},$ ${}^{25--27}\mathrm{F},$ and ${}^{28\ensuremath{-}30}\mathrm{Ne}$ have been measured. The nuclides were produced in the quasifragmentation of a 2.8 GeV ${}^{36}\mathrm{S}$ beam, separated in-flight and identified through time-of-flight and energy-loss measurements. The ions were stopped in a silicon detector telescope, which was used to detect the $\ensuremath{\beta}$ particles emitted in their subsequent radioactive decay. The coincident $\ensuremath{\gamma}$ rays were measured using four large volume germanium detectors mounted close to the implantation point and the …
Identification of a millisecond isomeric state inCd81129via the detection of internal conversion and Compton electrons
2014
Abstract The decay of an isomeric state in the neutron-rich nucleus 129 Cd has been observed via the detection of internal conversion and Compton electrons providing first experimental information on excited states in this nucleus. The isomer was populated in the projectile fission of a 238 U beam at the Radioactive Isotope Beam Factory at RIKEN. From the measured yields of γ -rays and internal conversion electrons, a multipolarity of E 3 was tentatively assigned to the isomeric transition. A half-life of T 1 / 2 = 3.6 ( 2 ) ms was determined for the new state which was assigned a spin of ( 21 / 2 + ) , based on a comparison to shell model calculations performed using state-of-the-art reali…
Probing double beta decay by nuclear muon capture
2005
A reliable theoretical calculations on two-neutrino and neutrinoless double-beta-decay rates requires a solid description about the nuclear structure of the intermediate nuclear states. It has been suggested that the ordinary muon capture could be used to probe the structure of the intermediate states in double beta decays.
Conversion electron and beta decay spectroscopy at SHIP
2004
Abstract Novel methods for internal conversion electron and β -decay spectroscopy at the focal plane of a recoil separator are discussed. As an example the experimental data collected at the focal plane of the velocity filter SHIP (GSI, Darmstadt) are presented and compared with the results of the GEANT Monte Carlo simulations. It is shown that the simultaneous detection of conversion electrons, γ -rays and X-rays is possible, which significantly broadens the range of applications of this and similar systems.
Observation of a dramatic hindrance of the nuclear decay of isomeric states for fully ionized atoms
2003
Abstract The half-lives of isomeric states of fully ionized 144Tb, 149Dy and 151Er have been measured. These nuclides were produced via fragmentation of about 900 MeV/u 209Bi projectiles, separated in flight with the fragment separator (FRS) and stored in the cooler ring (ESR). The decay times of the cooled fragments have been measured with time-resolved Schottky spectrometry. We observed for the first time drastic increases of the half-lives of bare isomers by factors of up to 30 compared to their neutral counterparts. This is due to the exclusion of the strong internal conversion and electron-capture channels in the radioactive decay of these bare nuclei. The experimental results are in g…