Search results for "DECAY"
showing 10 items of 2087 documents
First candidates for γ vibrational bands built on the [505]11/2⁻ neutron orbital in odd-A Dy isotopes
2020
Rotational structures have been measured using the Jurogam II and GAMMASPHERE arrays at low spin following the 155Gd(α,2n)157Dy and 148Nd(12C,5n)155Dy reactions at 25 and 65 MeV, respectively. We report high-K bands, which are conjectured to be the first candidates of a Kπ=2+γ vibrational band, built on the [505]11/2− neutron orbital, in both odd-A155,157Dy isotopes. The coupling of the first excited K=0+ states or the so-called β vibrational bands at 661 and 676 keV in 154Dy and 156Dy to the [505]11/2− orbital, to produce a Kπ=11/2− band, was not observed in both 155Dy and 157Dy, respectively. The implication of these findings on the interpretation of the first excited 0+ states in the cor…
Decay spectroscopy of 179 82 Pb 97 and evidence for a 9/2− intruder state in 179 81 Tl 98
2017
The very neutron-deficient isobars 179Pb and 179Tl have been produced using the fusion-evaporation reactions 104Pd(78Kr,xpyn), where x≤1 and y≥2. The gas-filled separator RITU was employed to transport and separate the recoiling nuclei of interest from the scattered beam and unwanted products. The GREAT spectrometer was used to study the decay properties through α−α and α−γ correlations, which has allowed the ground state of 179Pb to be assigned as Iπ=9/2−. The decay of 179Pb was measured to have an α-particle energy and half-life of Eα=7348(5)keV and t1/2=2.7(2) ms, respectively. A search for a νi13/2 state in 179Pb was performed, but only a limit of excitation energy and half-life was obt…
Half-lives for highly forbidden beta decays in medium-heavy nuclei
2016
Kuudellekymmenelle aiemmin tutkimattomalle uniikille beetahajoamiselle laskettiin puoliintumisajat ja tuloksia verrattiin aiempiin tutkimuksiin koskien kerran kiellettyjä uniikkeja siirtymiä ja Gamow-Teller-siirtymiä. Half-lives for 60 previously unstudied highly forbidden beta decays were calculated, and the results compared to earlier studies regarding first-forbidden and Gamow-Teller-decays.
Charged-current neutrino and antineutrino scattering off 116Cd described by Skyrme forces
2014
We perform calculations of the cross sections for charged-current neutrino and antineutrino scattering off 116Cd using ten different Skyrme interactions, at energies typical of supernova neutrinos. We use the quasiparticle random-phase approximation in its charged-changing mode (pnQRPA) to construct the required nuclear wave functions for the participant initial and final states. We compare the results of these calculations with the results of calculations based on the Bonn one-boson-exchange potential. The response of 116Cd to supernova neutrinos is calculated by folding the obtained cross sections with suitably parametrized Fermi-Dirac distributions of the electron-neutrino and electron-a…
Octupole states in 207Tl studied through β decay
2020
The β decay of 207Hg into the single-proton-hole nucleus 207Tl has been studied through γ-ray spectroscopy at the ISOLDE Decay Station (IDS) with the aim of identifying states resulting from coupling of the πs−11/2, πd−13/2, and πh−111/2 shell model orbitals to the collective octupole vibration. Twenty-two states were observed lying between 2.6 and 4.0 MeV, eleven of which were observed for the first time, and 78 new transitions were placed. Two octupole states (s1/2-coupled) are identified and three more states (d3/2-coupled) are tentatively assigned using spin-parity inferences, while further h11/2-coupled states may also have been observed for the first time. Comparisons are made with st…
Identical transitions in the strongly deformed 99Sr and 100Sr
2001
The decay of the very neutron-rich nucleus 100 Rb has been studied by γ spectroscopy of online mass-separated samples. Schemes for β decay to 100 Sr and β n decay to 99 Sr are presented. New sets of transitions in 99 Sr and 100 Sr with identical energies are observed. All identical bands so far observed in neutron-rich Sr isotopes obey a simple energy rule valid for even-even, odd-even, and odd-odd bands. peerReviewed
Direct measurement of the mass difference of $^{72}$As-$^{72}$Ge rules out $^{72}$As as a promising $\beta$-decay candidate to determine the neutrino…
2021
We report the first direct determination of the ground-state to ground-state electron-capture $Q$-value for the $^{72}$As to $^{72}$Ge decay by measuring their atomic mass difference utilizing the double Penning trap mass spectrometer, JYFLTRAP. The $Q$-value was measured to be 4343.596(75)~keV, which is more than a 50-fold improvement in precision compared to the value in the most recent Atomic Mass Evaluation 2020. Furthermore, the new $Q$-value was found to be 12.4(40)~keV (3.1 $\sigma$) lower. With the significant reduction of the uncertainty of the ground-state to ground-state $Q$-value value combined with the level scheme of $^{72}$Ge from $\gamma$-ray spectroscopy, we confirm that th…
Evolution of deformation in neutron-rich Ba isotopes up to A=150
2018
12 pags., 11 figs., 3 tabs. -- Open Access funded by Creative Commons Atribution Licence 4.0
Alpha-decay studies of the nuclides 195Rn and 196Rn
2001
The new neutron deficient nuclide 195 Rn and the nuclide 196 Rn have been produced in fusion evaporation reactions using 56 Fe ions on 142 Nd targets. A gas-filled recoil separator was used to separate the fusion products from the scattered beam. The activities were implanted in a position sensitive silicon detector. The isotopes were identified using spatial and time correlations between implants and decays. Two α decaying isomeric states, with E α = 7536 ( 11 ) keV [ T 1 / 2 = ( 6 + 3 − 2 ) ms ] for the ground state and E α = 7555 ( 11 ) keV [ T 1 / 2 = ( 5 + 3 − 2 ) ms ] for an isomeric state were identified in 195 Rn . In addition, the half-life and α decay energy of 196 Rn were measure…
Photoluminescence time decay of surface oxygen deficient centers in un‐doped and Ge‐doped silica
2005
We report a study of the emission decay from the singlet excited state of two fold coordinated Si and Ge centers stabilized on the surface of silica and Ge-doped silica. The PL lifetimes are of the order of nanoseconds and increase on decreasing the temperature. The results suggest that, for the surface centers, the phonon assisted intersystem-crossing process linking the excited states affects the decay rates, is effective down to low temperatures and is distributed because of the inhomogeneity of the defects. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)