0000000000067674
AUTHOR
Zs. Dombrádi
Evidence for a spin-aligned neutron-proton paired phase from the level structure of (92)Pd
4 páginas, 4 figuras.-- El Pdf es la versión pre-print.-- et al.
Study of $^{45}$Ar through (d, p) reaction at SPIRAL
NESTER; International audience; The structure of the neutron-rich nucleus $^{45}$Ar has been investigated through the d($^{44}$Ar,$^{45}$Ar)p transfer reaction. Radioactive beam of $^{44}$Ar at 10 A MeV has been provided by the SPIRAL facility at GANIL. The protons corresponding to a neutron pick-up on bound or unbound states mechanism in $^{45}$Ar nuclei were detected at backward angles by the detector array MUST. The transfer-like ejectiles were detected in the SPEG spectrometer. Level scheme, spin assignments and spectroscopic factors have been deduced for $^{45}$Ar and compared to shell model predictions. These parameters will be subsequently used to infer (n, $\gamma$) cross sections i…
γ-ray linear polarization measurements and(g9/2)−3neutron alignment in91Ru
The authors would like to thank the operators of the GANIL cyclotrons for providing the 36Ar beam. We would also like to thank the EXOGAM Collaboration for use of the clover Ge detector array, the DIAMANT Collaboration for use of the charged particle detector system, and the European gamma-ray Spectroscopy Pool for use of the neutron detector system. We acknowledge funding support from the French-Polish LEA COPIGAL and the IN2P3-Polish laboratories COPIN Agreement No. 06-122, from the UK STFC, from the Swedish Research Council (Contracts No. 2007-4067 and No. 2008-5793), from the Goran Gustafsson Foundation, from the OTKA under Contract No. K100835, and from the Bolyai Janos Foundation. AG …
β decay of Ni75 and the systematics of the low-lying level structure of neutron-rich odd- A Cu isotopes
Background: Detailed spectroscopy of neutron-rich odd-A Cu isotopes is of great importance for studying the shell evolution in the region of Ni78. While there is experimental information on excited states in Cu69−73,77,79 isotopes, the information concerning Cu75 is very limited. Purpose: Experimentally observed single-particle, core-coupling, and proton-hole intruder states in Cu75, will complete the systematics of these states in the chain of isotopes. Method: Excited states in Cu75 were populated in the β decay of Ni75 isotopes. The Ni nuclei were produced by the in-flight fission of U238 projectiles, and were separated, identified, and implanted in a highly segmented Si detector array f…
Role of the Δ Resonance in the Population of a Four-Nucleon State in the Fe56→Fe54 Reaction at Relativistic Energies
The 54Fe nucleus was populated from a 56Fe beam impinging on a Be target with an energy of E=A ¼ 500 MeV. The internal decay via γ-ray emission of the 10þ metastable state was observed. As the structure of this isomeric state has to involve at least four unpaired nucleons, it cannot be populated in a simple two-neutron removal reaction from the 56Fe ground state. The isomeric state was produced in the low-momentum (-energy) tail of the parallel momentum (energy) distribution of 54Fe, suggesting that it was populated via the decay of the Δ0 resonance into a proton. This process allows the population of fournucleon states, such as the observed isomer. Therefore, it is concluded that the obser…
Nuclear structure “southeast” ofPb208: Isomeric states inHg208andTl209
The nuclear structure of neutron-rich N>126 nuclei has been investigated following their production via relativistic projectile fragmentation of a E/A=1 GeV U-238 beam. Metastable states in the N=128 isotones Hg-208 and Tl-209 have been identified. Delayed gamma-ray transitions are interpreted as arising from the decay of I-pi=(8(+)) and (17/2(+)) isomers, respectively. The data allow for the so far most comprehensive verification of the shell-model approach in the region determined by magic numbers Z 126.
Structure of 106In nucleus
Abstract Single-γ, γγ-coincidence, and γ-ray angular distribution spectra of the 106Cd(p, nγ)106In reaction were measured with Ge(HP), Ge(Li), and Ge(LEPS) detectors at various bombarding proton energies between 8 and 11 MeV. Altogether 141 (among them 117 new) transitions have been assigned to 106In. The conversion electrons were studied with an intermediate-image magnetic spectrometer plus Si(Li) detector, as well as with a superconducting magnetic lens combined with a Si(Li) detector. Internal conversion coefficients have been determined for 22 transitions. A more complete level scheme of 106In, containing 49 levels below 1650 keV excitation energy, has been proposed. On the basis of the…
In-beam γ-ray spectroscopy of 103Cd
Excited states of Cd-103 were studied in the reaction Ni-58(Cr-50,4pn)Cd-103. The NORDBALL array with neutron and charged particle detectors was employed for the detection of gamma rays and light evaporated particles. The level scheme of Cd-103 was significantly extended. A strong cascade of E2 transitions connecting negative parity states was found, Shell model calculations were performed and positive parity excited states were interpreted in terms of neutron-particle and proton-hole excitations with respect to the doubly magic N = Z = 50 core. The negative parity band was well reproduced by the total routhian surface calculations. (C) 1997 Elsevier Science B.V.
Low-lying excitations in Ni 72
A. I. Morales et al.; 14 págs.; 9 figs.; 3 tabs.
In-beam spectroscopy of 110Te
The neutron-deficient nucleus Te-110 has been investigated by in-beam spectroscopic methods using the NORDBALL multi-detector array. Except for the energy of one level observed in alpha-decay, exci ...
Structure ofIn112nucleus
The \ensuremath{\gamma}-ray spectra of the $^{112}\mathrm{Cd}$(p,n\ensuremath{\gamma}${)}^{112}$In and $^{109}\mathrm{Ag}$(\ensuremath{\alpha},n\ensuremath{\gamma}${)}^{112}$In reactions were measured with Ge(Li) spectrometers for bombarding energies of 4.8 MeV protons and 17.1 MeV \ensuremath{\alpha} particles. The energies and relative intensities of 79 $^{112}\mathrm{In}$ \ensuremath{\gamma}-ray transitions have been determined. The electron spectra were measured with combined magnet plus Si(Li) as well as superconducting magnetic lens plus Si(Li) spectrometers. Internal conversion coefficients of 40 $^{112}\mathrm{In}$ transitions have been determined, and the level scheme of $^{112}\ma…
Stability of chiral geometry in the odd–odd Rh isotopes: spectroscopy of 106Rh
International audience; 136 P. Joshi et al. / Physics Letters B 595 (2004) 135–142AbstractThe nucleus 106Rh was populated using the reaction 96Zr(13C, p2n) at a beam energy of 51 MeV. γ -ray transitions wereidentified using the EUROBALL-IV γ -ray spectrometer and the DIAMANT charged particle array. The yrast band, which isbased upon a πg−19/2 ⊗ νh11/2 configuration, has been extended to I π = (22−). A new I = 1 band has been identified whichresides ∼ 300 keV above the yrast band. Core–quasiparticle coupling model calculations show reasonably good agreement withthe data. The properties of the two pairs of strongly coupled bands are consistent with a chiral interpretation for these states. 2…
Simultaneous investigation of the T=1(Jπ=0+) and T=0(Jπ=9+) β decays in Br70
The $\beta$ decay of the odd-odd nucleus $^{70}$Br has been investigated with the BigRIPS and EURICA setups at the Radioactive Ion Beam Factory (RIBF) of the RIKEN Nishina Center. The $T=0$ ($J^{\pi}=9^+$) and $T=1$ ($J^{\pi}=0^+$) isomers have both been produced in in-flight fragmentation of $^{78}$Kr with ratios of 41.6(8)\% and 58.4(8)\%, respectively. A half-life of $t_{1/2}=2157^{+53}_{-49}$ ms has been measured for the $J^{\pi}=9^+$ isomer from $\gamma$-ray time decay analysis. Based on this result, we provide a new value of the half-life for the $J^{\pi}=0^+$ ground state of $^{70}$Br, $t_{1/2}=78.42\pm0.51$ ms, which is slightly more precise, and in excellent agreement, with the bes…
Shapes ofPb192,190ground states fromβ-decay studies using the total-absorption technique
The beta decay of Pb-192,Pb-190 has been studied using the total absorption technique at the ISOLDE (CERN) facility. The beta-decay strength deduced from the measurements, combined with QRPA theoretical calculations, allow us to infer that the ground states of the Pb-192,Pb-190 isotopes are spherical. These results represent the first application of the shape determination method using the total absorption technique for heavy nuclei and in a region where there is considerable interest in nuclear shapes and shape effects.
Hindered Gamow-Teller Decay to the Odd-OddN=ZGa62: Absence of Proton-NeutronT=0Condensate inA=62
Search for a new kind of superfluidity built on collective proton-neutron pairs with aligned spin is performed studying the Gamow-Teller decay of the T=1, Jπ=0+ ground state of Ge62 into excited states of the odd-odd N=Z nucleus Ga62. The experiment is performed at GSI Helmholtzzentrum fur Schwerionenforschung with the Ge62 ions selected by the fragment separator and implanted in a stack of Si-strip detectors, surrounded by the RISING Ge array. A half-life of T1/2=82.9(14) ms is measured for the Ge62 ground state. Six excited states of Ga62, populated below 2.5 MeV through Gamow-Teller transitions, are identified. Individual Gamow-Teller transition strengths agree well with theoretical pred…
Isospin dependence of electromagnetic transition strengths among an isobaric triplet
*Aydın, Sezgin ( Aksaray, Yazar )
Structure ofSb118nucleus
{gamma}, {gamma}{gamma}-coincidence, internal conversion electron, and {gamma}-ray angular distribution spectra of the {sup 118}Sn({ital p},{ital n}{gamma}){sup 118}Sb reaction were measured at different bombarding proton energies between 5.5 and 7.5 MeV. {gamma}, {gamma}{gamma}-coincidence, and internal conversion electron spectra of the {sup 115}In ({alpha},{ital n}{gamma}){sup 118}Sb reaction were also measured at {ital E}{sub {alpha}}=14.5 MeV. Ge(HP), Ge(Li), Ge(LEPS) {gamma}-ray detectors, as well as a superconducting magnetic lens electron spectrometer (with Si(Li) detectors), were used in the experiments. About 210 (including {similar to}130 new) {gamma} rays have been assigned to {…
Lifetime Measurements with the Doppler Shift Attenuation Method Using a Thick Homogeneous Production Target — Verification of the Method
International audience; Doppler Shift Attenuation Method (DSAM) analysis of excited-state lifetimes normally employs thin production targets mounted on a thick stopper foil (“backing”) serving to slow down and stop the recoiling nuclei of interest in a well-defined manner. Use of a thick, homogeneous production target leads to a more complex analysis as it results in a substantial decrease in the energy of the incident projectile which traverses the target with an associated change in the production cross section of the residues as a function of penetration depth. Here, a DSAM lifetime analysis using a thick homogeneous target has been verified using the Doppler broadened lineshapes of γ ra…
$^{78}$Ni revealed as a doubly magic stronghold against nuclear deformation
Nuclear magic numbers, which emerge from the strong nuclear force based on quantum chromodynamics, correspond to fully occupied energy shells of protons, or neutrons inside atomic nuclei. Doubly magic nuclei, with magic numbers for both protons and neutrons, are spherical and extremely rare across the nuclear landscape. While the sequence of magic numbers is well established for stable nuclei, evidence reveals modifications for nuclei with a large proton-to-neutron asymmetry. Here, we provide the first spectroscopic study of the doubly magic nucleus $^{78}$Ni, fourteen neutrons beyond the last stable nickel isotope. We provide direct evidence for its doubly magic nature, which is also predi…
Identification and spectroscopy of the108Te nucleus
Excited states of 108 Te were populated in the 54 Fe + 58 Ni (270 MeV) reaction using the NORDBALL detector array equipped with charged-particle and neutron detector systems for reaction channel separation. Gamma rays belonging to the neutron deficient nucleus 108 Te were identified for the first time. On the basis of γγ-coincidence and angular correlation relations a level scheme was constructed with tentative spin and parity assignments. The structure of the nucleus is discussed in the framework of systematics of heavier Te nuclei.