No abstract
Ground and isomeric proton and alpha decay branches are reported for the new isotope 177 Tl, produced by bombarding a 102 Pd target with a 370 MeV beam of 78 Kr ions. The ground state is assigned as a s 1/2 configuration and the high spin isomer is assigned as a (h 11/2 ) Ϫ1 configuration. The ground-state proton decay of 171 Au has been identified for the first time, produced by bombarding a 96 Ru target with 78 Kr ions. The 171 Au ground state is also assigned as a s 1/2 configuration. Spectroscopic factors, masses, and proton separation energies are derived using these new proton decay measurements. New ground-state ␣ decays for 169 Ir and 173 Au are also reported. ͓S0556-2813͑99͒50206-9͔ PACS number͑s͒: 23.50.ϩz, 23.60.ϩe, 21.10.Pc, 27.70.ϩq Proton radioactivity measurements in the region of the drip-line from Zϭ69-79 ͓1͔ have revealed detailed information on the positions of single-particle levels, proton binding, and proton decay rates. In all cases protons have been identified as originating from approximately degenerate s 1/2 , d 3/2 , or h 11/2 orbitals. A proton decay spectroscopic factor S l j derived from a low seniority shell model calculation assuming degenerate single particle states reproduces the systematic variation in proton decay rates very well ͓1͔, as does a more sophisticated approach ͓2͔. It is of interest to extend these measurements to Tl nuclei since they reside immediately below the Zϭ82 shell closure. The most neutrondeficient Tl isotope identified to date is 179 Tl ͓3,4͔, which has ␣-decay branches from a low and a high spin state. Nearer to stability it has been shown that odd-A Tl isotopes are characterized as having a s 1/2 ground state with an isomeric h 9/2 intruder state configuration that involves the promotion of a proton from the s 1/2 orbital across the Z ϭ82 shell closure ͓5͔. It is known that these intruder states reach a minimum excitation energy of 281 keV for 189 Tl, which approximately corresponds to the neutron mid-shell. On either side of this minimum there is predicted to be a parabolic increase in excitation energy of the intruder due to the reduced interaction strength between the valence neutrons and the proton hole ͓6͔. This behavior is closely followed nearer to stability, but the information on neutrondeficient isotopes is somewhat limited, with 183 Tl being the lightest isotope for which the intruder state has been clearly identified ͑at an excitation energy of 625 keV ͓7͔͒. It is clearly of great interest to identify proton radioactivity from Tl isotopes both to obtain insight into the variation in proton decay rates in this region, and to study the low energy structure at the extreme limit of stability. The present paper describes a successful search for proton radioactivity from 177 Tl. A 4 pnA beam of 370 MeV 78 Kr ions from the Argonne ATLAS accelerator facility was used to bombard a 1 mg/cm 2 78% enriched 102 Pd target for a period of 65 hours in order to produce 177 Tl nuclei via the 1 p2n fusionevaporation channel. The Argonne Fragment Mass Analyz...
A high-spin isomer in 145 Sm was discovered by using Inverse kinematic reactions, 20 Ne e Xe,a7n) 145 Sm and 16 0 e 36 Xe,7n) 145 Sm. The half life was determined to be 0.96 J.LSec. Sixty-five 1-rays were identified by the /')'-coincidence measurements to belong to the isomer decay. The low-lying level scheme of 145 Sm was established in detail by the in-beam 1-ray measurements using the 139 La e 0 B,4n) 145 Sm reaction. A complex decay scheme of this isomer was constructed by using the data obtained from the 136 Xe induced reactions, combining the informations of low-lying states mentioned above. The excitation energy of this isomer was determined to be 8.8 MeV. The /')'-coincidence measurement using the 138 Ba (13 C,6n) 145 Sm reaction was also performed. Based on this information, the level scheme above the high-spin isomer was extended up to the state at 14.6 MeV. A 1-ray angular distribution measurement using the same reaction with pulsed beam was carried out and was used to assign a spin value of each level. Low-lying states in 145 Sm were interpreted to originate from a single neutron coupled to the 144 Sm core excitation. Experimental yrast states were compared with a calculation of a deformed independent particle model (DIPM). A configuration of the high-spin isomer was deduced by the DIPM calculation to be { 7r h ll /2 2 v (f 7 /2 h 9/2 i 13/2) } 49/2+ .
Using the phenomenological optical potential and two different semi-microscopic potentials, namely double folding and cluster folding (CF), the available experimental data for 6Li elastically scattered from [Formula: see text]C nucleus at energies 50–600[Formula: see text]MeV are reanalyzed. On the basis of the well-known cluster structure of 6Li as a composite nucleus consisting of a core “alpha” with a valence particle “deuteron” orbiting this core, special attention was paid to the CF potential. Elastic scattering data for 6Li+[Formula: see text]C system plotted as a function of momentum transfer showed that the real Coulomb nuclear interference region is independent of the bombarding energy. The aforementioned structural behavior for the data could be used to define the potential with some certainty. In addition to a Woods–Saxon imaginary potential of fixed radius, the real part of the potential derived from the cluster structure of 6Li was successful in reproducing the experimental data in the whole angular range. Coupled channel (CC) calculation effects are also performed by coupling to 6Li resonant state ([Formula: see text], [Formula: see text][Formula: see text]MeV).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.