Search results for "INTRUDER"
showing 8 items of 18 documents
Investigations into the alpha-decay of 195At
2003
The low-energy nuclear structure and decay properties of the neutron-deficient isotopes 195At and 191Bi have been studied. 195At was produced in the reaction 142Nd(56Fe,p2n)195At and 191Bi as the daughter activity of 195At. The activities were implanted in a position-sensitive silicon detector after being separated from the primary beam by a gas-filled recoil separator. The 1/2+ intruder state was determined to be the ground state in 195At with an alpha-decay energy of E α = 6953(3) keV and a half-life T 1/2 = 328(20) ms. Another state with an alpha-decay energy E α = 7075(4) keV and a half-life T 1/2 = 147(5) ms was found to decay to a 148.7(5) keV excited state in 191Bi for which a spin a…
Half-life and configuration of the 1/2+ intruder state in203Bi
1984
The decay properties of theJπ=1/2+,Eexc=1,098 keV state in203Bi were studied. The state was populated via the204Pb(p, 2n) reaction and the activity was studied with the ion guide isotope separator on-line system IGISOL. The half-life of the 1/2+ state was measured to beT1/2=303 ±5 ms. From this value the partial half-lives of the three depopulating branches 1/2+ →7/2− (E3), 1/2+→5/2− (E3 +M2) and 1/2+→9/2 g.s. − (M4) were deduced. Since all the transitions are configuration forbidden in first order, a detailed study of second-order shell-model configuration mixing could be performed.
Proton Decay of an Intruder State inB185i
1996
The new proton radioactivity ${}^{185m}\mathrm{Bi}$ has been observed, produced via the ${}^{95}\mathrm{Mo}{(}^{92}\mathrm{Mo},pn{)}^{185}\mathrm{Bi}$ reaction. Its decay proceeds from the low-lying ${\frac{1}{2}}^{+}$ intruder state in ${}^{185}\mathrm{Bi}$ to the ${}^{184}\mathrm{Pb}$ ground state with the emission of a proton of energy $1.585\ifmmode\pm\else\textpm\fi{}0.009\mathrm{MeV}$ and a half-life of $44\ifmmode\pm\else\textpm\fi{}16\ensuremath{\mu}\mathrm{s}$. This marks the first observation of proton radioactivity above the $Z\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}82$ closed shell, and it has been used to obtain the admixture of a ${0}^{+}$ intruder state in ${}^{184…
Système de sécurité biométrique multimodal par imagerie, dédié au contrôle d’accès
2019
Research of this thesis consists in setting up efficient and light solutions to answer the problems of securing sensitive products. Motivated by a collaboration with various stakeholders within the Nuc-Track project, the development of a biometric security system, possibly multimodal, will lead to a study on various biometric features such as the face, fingerprints and the vascular network. This thesis will focus on an algorithm and architecture matching, with the aim of minimizing the storage size of the learning models while guaranteeing optimal performances. This will allow it to be stored on a personal support, thus respecting privacy standards.
Experimental study of isomeric intruder ½+ states 197,203At
2017
A newly observed isomeric intruder ½ + state [ T ½ = 3.5 ( 6 ) ms ] is identified in 203 At using a gas-filled recoil separator and fusion-evaporation reactions. The isomer is depopulated through a cascade of E 3 and mixed M 1 / E 2 transitions to the 9 / 2 − ground state, and it is suggested to originate from the π ( s ½ ) − 1 configuration. In addition, the structures above the ½ + state in 203 At and 197 At are studied using in-beam γ -ray spectroscopy, recoil-decay tagging, and recoil-isomer decay tagging methods. The ½ + state is fed from 3 / 2 + and 5 / 2 + states, and the origin of these states are discussed. peerReviewed
De-excitation of the strongly coupled band in 177Au and implications for core intruder configurations in the light Hg isotopes
2017
International audience; Excited states in the proton-unbound nuclide $^{177}$Au were populated in the $^92}$Mo($^{88}$Sr, p2n) reaction and identified using the Jurogam-II and GREAT spectrometers in conjunction with the RITU gas-filled separator at the University of Jyväskylä Accelerator Laboratory. A strongly coupled band and its decay path to the 11/2−α-decaying isomer have been identified using recoil-decay tagging. Comparisons with cranked Hartree-Fock-Bogoliubov (HFB) calculations based on Skyrme energy functionals suggest that the band has a prolate deformation and is based upon coupling the odd 1h11/2 proton hole to the excited 02+ configuration in the $^{178}$Hg core. Although these…
Shape coexistence in the neutron-deficient even-even Hg182-188 isotopes studied via Coulomb excitation
2014
Coulomb-excitation experiments to study electromagnetic properties of radioactive even-even Hg isotopes were performed with 2.85 MeV/nucleon mercury beams from REX-ISOLDE. Magnitudes and relative signs of the reduced E2 matrix elements that couple the ground state and low-lying excited states in Hg182-188 were extracted. Information on the deformation of the ground and the first excited 0+ states was deduced using the quadrupole sum rules approach. Results show that the ground state is slightly deformed and of oblate nature, while a larger deformation for the excited 0+ state was noted in Hg182,184. The results are compared to beyond mean field and interacting-boson based models and interp…
Evidence for Shape Coexistence in Neutron-Rich Rh and Ag Nuclei
1988
Neutron-rich nuclei of Rh and Ag have been investigated by γ-ray spectroscopic measurements as well as single-particle transfer reactions like (d,3He) and (3He,d). The obtained level schemes of 105,107,109,111Rh and 113,115Ag show two different types of excitation: (I) proton-hole states related to a spherical shape of the nucleus and (II) proton-particle states with a rotational band-like structure (intruder band) pointing towards deformation of the nucleus. The “fingerprints” for such a shape coexistence and resulting systematics in these nuclei and the possible interpretation of the intruder band as a rotational band built upon the 1/2+[431] Nilsson configuration are discussed.