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2019, Nucleus
The estimation of spectroscopic properties of neutron-deficient nuclei in the A=100 tin mass region is needed for the understanding of the rp-process path and the experimental exploration of the nuclear landscape. In order to evaluate some spectroscopic properties of the Gamow-Teller β+ decay of neutron deficient isobars of A=100, we have performed shell model calculations by means of Oxbash nuclear structure code. The jj45pn valence space used consists of nine proton and neutron orbitals. The calculations included few valence hole-proton and particle-neutronin π g9/2 and vg7/2 orbitals respectively, in 100Sn doubly magic core. Effective interaction deduced from CD-Bonn one is introduced taking into account the nuclear monopole effect in this mass region. The results are then compared with the available experimental data.
Journal of Basrah Researches ((Sciences)) Vol. (41). No. (1) A (2015), 2015
The nuclear structure of A=110 (Mo, Ru, Pd and Cd) isobars has been investigated using the proton-neutron interacting boson model (IBM-2). The energy levels and electromagnetic transition probabilities have been calculated. The symmetry and mixed symmetry 2 + states are identified as arising from boson number weighted symmetry and anti-symmetry vibrations in the degree of freedom. The influence of model parameters and F-spin mixing on the energy of and states suggested that these states are F = F max-1 (mixed-symmetry) states in these isobars.
The β + /EC-decay of 100 In, the one proton-hole and one neutron-particle neighbour nucleus to the doubly-magic 100 Sn, was investigated at the GSI ISOL facility by using a Germanium detector array for high-resolution spectroscopy and a highly-efficient NaI total-absorption spectrometer (TAS) to measure the Gamow-Teller (GT) strength and distribution. The beta-decay scheme was studied for the first time. Large-scale shell-model calculations using a realistic interaction are used to assign configurations to low-lying states in 100 In and 100 Cd. The experimental GT beta-decay strength distributions as measured in TAS are compared to shell-model predictions. The hindrance factor for the total GT strength amounts to h=4.1(9). This value agrees well with a value extrapolated for the GT resonance in 100 Sn from previously measured values in neighbouring nuclei.
Zeitschrift f�r Physik A Atomic Nuclei, 1988
With the use of the 58Ni+S~ fusion-evaporation reaction and chemically selective on-line mass separation, the EC//3 + decay of t~ was studied by ?-ray and conversionelectron spectroscopy. In the course of these studies, a new 15.7-s isomeric state of t~ was observed. Reinvestigation of the {/-decays of the two heavier even isotopes of tin, produced in the s 8Ni + 58Ni reaction and mass separated without chemical discrimination, brought new information on the decay of l~ and ~~ The QEc values of 1~ l~ and 1~ were determined to be 4550 +300 keV, 3200+100 keV and-250 <2270 keV, respectively. In the data analysis, the emphasis is put on the identification of the 0+-~ 1 + Gamow-Teller /~ transitions and determination of their strengths. For 1~176 the total Gamow-Teller strengths are measured to be 20% to 30% of that predicted by the single-particle shell model with the inclusion of pairing correlations and core polarization. Predictions of the decay properties of the as yet unobserved ~~ and l~176 are made.
Physical review letters, 2014
This Letter reports on a systematic study of β-decay half-lives of neutron-rich nuclei around doubly magic (208)Pb. The lifetimes of the 126-neutron shell isotone (204)Pt and the neighboring (200-202)Ir, (203)Pt, (204)Au are presented together with other 19 half-lives measured during the "stopped beam" campaign of the rare isotope investigations at GSI collaboration. The results constrain the main nuclear theories used in calculations of r-process nucleosynthesis. Predictions based on a statistical macroscopic description of the first-forbidden β strength reveal significant deviations for most of the nuclei with N<126. In contrast, theories including a fully microscopic treatment of allowed and first-forbidden transitions reproduce more satisfactorily the trend in the measured half-lives for the nuclei in this region, where the r-process pathway passes through during β decay back to stability.
Nuclear Physics A, 2002
The first information on the level structure of the N=21 nuclei, 35 Si and 33 Mg, has been obtained by the beta decay study of 35 Al and 33 Na, produced by fragmentation of an UC target with 1.4 GeV protons at CERN/ISOLDE. The experimental technique involved β-γ, β-γ-γ, and β-n-γ coincidences, neutron spectra being obtained by time of flight measurements. Gamma detection was made either using large Ge counters or small BaF 2 scintillators (for lifetime measurements). In the case of the 35 Al decay, (T 1/2 = 41.6(2.2)ms), a simple structure has been found for the level scheme of 35 Si (Z=14, N=21) which has been interpreted with the level sequence : 7/2 − , 3/2 − and 3/2 + corresponding respectively to the ground state and the states at 910 and 974 keV. The lifetime of the 974 keV [T 1/2 = 5.9(6)ns] is found consistent with the proposed level scheme and multipolarities. The investigation of the N=21, very neutron rich isotones, has been carried on with the study of 33 Mg resulting from the 33 Na decay, (T 1/2 = 8.0(6) ms). In this case also, a level scheme could be obtained for the first time, with 5 bound states in 32 Mg and 31 Mg levels, populated in the 1n and 2n channels. These results are compared with sd-fp shell model calculations which give a fair account of the Gamow-Teller distribution and a reasonable explanation of the lowest levels with predominant contribution of 1p-1h and 2p-2h excitations.
Physical Review Letters, 2019
A record number of 100 Sn nuclei was detected and new isotopic species toward the proton dripline were discovered at the RIKEN Nishina Center. Decay spectroscopy was performed with the high-efficiency detector arrays WAS3ABi and EURICA. Both the half-life and the β-decay end point energy of 100 Sn were measured more precisely than the literature values. The value and the uncertainty of the resulting strength for the pure 0 þ → 1 þ Gamow-Teller decay was improved to B GT ¼ 4.4 þ0.9 −0.7. A discrimination between different model calculations was possible for the first time, and the level scheme of 100 In is investigated further.
2007
The decay of excited states in the waiting-point nucleus 130 Cd 82 has been observed for the first time. An 8 two-quasiparticle isomer has been populated both in the fragmentation of a 136 Xe beam as well as in projectile fission of 238 U, making 130 Cd the most neutron-rich N 82 isotone for which information about excited states is available. The results, interpreted using state-of-the-art nuclear shell-model calculations, show no evidence of an N 82 shell quenching at Z 48. They allow us to follow nuclear isomerism throughout a full major neutron shell from 98 Cd 50 to 130 Cd 82 and reveal, in comparison with 76 Ni 48 one major proton shell below, an apparently abnormal scaling of nuclear two-body interactions.
EPJ Web of Conferences, 2017
The monopole effect resulting from the interaction between the magic core and the valence particles has a particular interest in the study of nuclear structure. To understand the importance of this interaction, we have realized some spectroscopic calculations for odd-odd In isotopes containing one hole proton and few neutron particles in addition to 100 Sn doubly magic core in their valence spaces. The using interaction is derived from jj45apn one taking into account the monopole interaction in the studied mass region, and using recent single particle and hole energies. The calculations are performed in the framework of the nuclear shell model by means of Oxbash nuclear structure code.
The European Physical …, 2000
The decay of the neutron-rich isotope 216 Bi, produced by proton-induced spallation at the PS Booster-ISOLDE facility, was investigated by β − γγ, αγ coincidence and spectrum-multiscaling measurements. A new method for reducing isobaric contamination enabled to cover the unknown region "east" of 208 Pb for the isobaric chain A=216. The half-life of the β decay of 216 Bi was found as T 1/2 = 135 ± 5 s. Its decay scheme was extended and the possible shell model configurations are proposed.
The European Physical Journal A - Hadrons and Nuclei, 2002
Neutron deficient nuclei near 100 Sn have been produced by fragmentation of a 1 · A GeV 112 Sn beam. The fragments were separated, identified and stopped in a highly segmented silicon strip detector stack. This detector measured the total energy of emitted β + -particles. γ-radiation was measured with surrounding detectors. The half-lives for many nuclides have been determined for the first time and give important information for the following topics: For the heaviest particle-stable odd-odd nuclei 90 Rh, 94 Ag and 98 In we observed for the first time fast β-decays, compatible with superallowed Fermi transitions and confirmed such decays for 78 Y, 82 Nb and 86 Tc. We have also observed long-lived T = 0 states in some of these nuclei. We measured the half-lives of all rp-process waiting-point nuclei from 80 Zr up to 92,93 Pd. In addition we find the proton drip line nucleus 77 Y to decay dominantly via β-decay. To study the Gamov-Teller strength in the β-decay near the doubly magic 100 Sn we measured the half-life, β-and γ-spectrum of 102 Sn. We propose a level scheme for the daughter nuclide 102 In and deduce the Gamov-Teller strength (BGT = 4.0 ± 0.6). This is one of the largest values known.
Progress in Particle and Nuclear Physics, 2013
The European Physical Journal A, 2002
Neutron deficient nuclei near 100 Sn have been produced by fragmentation of a 1 • A GeV 112 Sn beam. The fragments were separated, identified and stopped in a highly segmented silicon strip detector stack. This detector measured the total energy of emitted β +-particles. γ-radiation was measured with surrounding detectors. The half-lives for many nuclides have been determined for the first time and give important information for the following topics: For the heaviest particle-stable odd-odd nuclei 90 Rh, 94 Ag and 98 In we observed for the first time fast β-decays, compatible with superallowed Fermi transitions and confirmed such decays for 78 Y, 82 Nb and 86 Tc. We have also observed long-lived T = 0 states in some of these nuclei. We measured the half-lives of all rp-process waiting-point nuclei from 80 Zr up to 92,93 Pd. In addition we find the proton drip line nucleus 77 Y to decay dominantly via β-decay. To study the Gamov-Teller strength in the β-decay near the doubly magic 100 Sn we measured the half-life, β-and γ-spectrum of 102 Sn. We propose a level scheme for the daughter nuclide 102 In and deduce the Gamov-Teller strength (BGT = 4.0 ± 0.6). This is one of the largest values known.
Zeitschrift für Physik A Atomic Nuclei, 1989
Neutron-deficient isotopes of cadmium were produced in the p(600 MeV)+natSn spaltation reaction. The ISOLDE facility provided mass-separated beams of these isotopes. The production yield was 103 to 104 atoms/s for l~176 and roughly two orders of magnitude less for 98Cd. The properties of the ~~176176176 decay were studied in detail by X-ray, y-ray and conversion electron spectroscopy. Forty nine y-transitions were assigned to this decay, and all but five of them were placed in the decay scheme. The half-life was determined to be 49.1+0.5 s. The QEC value of 3890+70keV was deduced from a comparison of experimental and theoretical /?+/(EC+/~ +) probability ratios. Seven 0+-*1 + Gamow-Teller transitions with log ft values between 3.5 and 4.9 were identified. The total (summed) strength is about five times smaller than predicted by the shell model for the transformation of a g9/2 proton into a g7/2 neutron. The quenching of the Gamow-Teller strength and other questions of nuclear structure are discussed for the ~~176 decay. The properties of 98Cd are inferred by extrapolation of 1~176176176 data, and some preliminary experimental results on 98Cd decay are presented.
EPJ Web of Conferences
A systematic study of the β-decay of neutron-deficient nuclei has been carried out and has provided spectroscopic information of importance for both nuclear structure and nuclear astrophysics. Following an overview of the most relevant achievements, we focus on the latest results on the β decay of 60Ge and 62Ge. We also summarise our results on the mass excesses in comparison with systematics and a recent measurement. Finally, we present updated half-life trends for Tz = -1/2, -1 and -2 neutron-deficient nuclides.
The European Physical Journal A, 2006
The β decays of 102 Sn and 104 Sn were studied by using high-resolution germanium detectors as well as a Total Absorption Spectrometer (TAS). For 104 Sn, with three new β-delayed γ-rays identified, the total Gamow-Teller strength (BGT) value of 2.7(3) was obtained. For 102 Sn, the γ-γ coincidence data were collected for the first time, allowing us to considerably extend the decay scheme. This scheme was used to unfold the TAS data and to deduce a BGT value of 4.2(8) for this decay. This result is compared to shell model predictions, yielding a hindrance factor of 3.6(7) in agreement with those obtained previously for 98 Cd and 100 In. Together with the latter two, 102 Sn completes the triplet of Z ≤ 50, N ≥ 50 nuclei with two proton holes, one proton hole and one neutron particle, and two neutron particles with respect to the doubly magic 100 Sn core. PACS. 21.10.-k Properties of nuclei; nuclear energy levels-23.40.-s Beta decay; double β decay; electron and muon capture-23.20.Lv Gamma transitions and level energies-27.60.+j 90 ≤ A ≤ 149
Physical Review Letters, 2006
Two new emitters 109 Xe and 105 Te were identified through the observation of the 109 Xe ! 105 Te ! 101 Sn -decay chain. The 109 Xe nuclei were produced in the fusion-evaporation reaction 54 Fe 58 Ni; 3n 109 Xe and studied using the Recoil Mass Spectrometer at the Holifield Radioactive Ion Beam Facility. Two transitions at E 4062 7 keV and E 3918 9 keV were interpreted as the l 2 and l 0 transitions from the 7=2 ground state in 109 Xe (T 1=2 13 2 ms) to the 5=2 ground state and a 7=2 excited state, located at 150 13 keV in 105 Te. The observation of the subsequent decay of 105 Te marks the discovery of the lightest known -decaying nucleus. The measured transition energy E 4703 5 keV and half-life T 1=2 620 70 ns were used to determine the reduced -decay width 2 . The ratio 2 105 Te = 2 213 Po of 3 indicates a superallowed character of the emission from 105 Te.
Cornell University - arXiv, 2022
One of the main ingredients in nuclear structure studies using shell model are the singleparticle energy (spe). In order to obtain these values accurately, experimental data is needed. The region around the doubly magic nuclide 100 Sn is very interesting for nuclear studies in terms of structure, reaction and nuclear astrophysics. Experimental spectrum data for the 101 Sn isotope is required for nuclear shell model studies to be carried out in this region. Since there is not enough experimental data in the literature, different approaches are used for the obtaining spe's for the region such as using the hole excitation spectrum in 131 Sn or using the lightest and closest isotope 107 Sn which figures the model space orbitals. In this work, we have performed second order polynomial fits of the tree single-particle states s 1/2 , d 3/2 and h 11/2 in the light Sn isotopes up to 113 Sn and 115 Sn which are not determined yet experimentally. By an extrapolation toward light Sn isotopes, we can obtain the excitation energies of all the single-particle states in 101 Sn. Subsequently, neutron spe's of the model space orbitals are defined. Shell model calculations for even and odd 102-107 Sn isotopes are carried out using the new interactions and the results are compared with the experimental data and results obtained using the widely used interaction sn100pn.
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