Étude des moments angulaires des niveaux du 215Po par une méthode de corrélations angulaires
Abstract
Angular correlations for transitions and have been measured. We propose angular moments , and for the ground state and excited states of 272 and 401 keV of 215Po, respectively.
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Cited by (10)
Nuclear data sheets for A = 215
2013, Nuclear Data SheetsThe evaluated spectroscopic data are presented for 12 known nuclides of mass 215 (Hg, Tl, Pb, Bi, Po, At, Rn, Fr, Ra, Ac, Th, Pa). For 215Hg, 215Tl, 215Pb, and 215Pa nuclei, no excited states are known. The decay characteristics of 215Hg and 215Tl are unknown. The decay scheme of 215Pb is considered as incomplete. Ordering of γ cascades in the decay of 36.9–s isomer of 215Bi and for high–spin states above 2251 keV in 215Fr are not established. High–spin excitations, including several isomeric states, are well known in 215Bi, 215Po, 215Rn, 215Fr, 215Ra, and 215Ac. No particle–transfer reaction data are available for any of the A=215 nuclei.
The rms charge radii for 215Pb, 215Bi, 215Po, 215Rn, 215Fr and 215Ra have been evaluated by Daniel Abriola, from extrapolation or interpolation of available evaluated data in 2013An02 for radii of respective Z chains using formula 9 in 2004An14.
This evaluation was carried out as part of ENSDD–workshop at VECC, Kolkata for Nuclear Structure and Decay Data, organized and hosted by VECC and Board of Research in Nuclear Sciences (BRNS) in Kolkata, India, November 26–29, 2012. This work supersedes the previous A = 215 evaluation (2001Br31) published by E. Browne which covered literature prior to May 2001.
Nuclear data sheets for A = 215, 219, 233, 227, 231
2001, Nuclear Data SheetsThe evaluator presents in this publication spectroscopic data and level schemes from radioactive decay and nuclear reaction studies for all nuclei with mass numbers A=215, 219, 223, 227, and 231. Nuclei with mass number A=215 have spherical shape, and their nuclear structure have been interpreted in terms of the shell model. Nuclei with mass number A=219 belong to a transitional region with spherical, quadrupole, and possibly octupole deformations; those with mass numbers A=223 and 227 belong to a newly studied region of coexisting quadrupole with possible octupole deformations; and nuclei with mass number A=231 essentially have quadrupole deformation. Highlights of this publication are given below: A recent study of the 206Pb(13C,4nγ) reaction (1998St24) has extended up to Jπ=61/2+ the previously known level scheme from 208Pb(13C,6nγ) (1988Fu10,1983Lo16). This study has provided a new interpretation for all the spectroscopic data above the 2247--keV (Jπ=29/2--) level in 215Ra. A new isotope, 219U (42 μs), which was identified with the recoil separator VASSILISSA (1994Ye08,1994AnZY,1993An07), has been included in this evaluation. The first 223Rn β-- decay scheme (1992Ku03) and a significantly improved measurement of 227Ac α decay (1995Sh03) are presented here. A level scheme of 223Fr has been constructed on the basis of these studies, where most of the levels below 600 keV have been assigned to parity doublet bands and interpreted in terms of the reflection--asymmetric rotor model. This evaluation includes the first level structures of 227Fr and 227Th. Levels in 227Fr are from 227Rn β-- decay (1997Ku20); those in 227Th, are from 231U α decay, from 227Pa electron--capture decay, and from 226Ra(α,3nγ) (1997Mu08,1995Li04,1998Ma83). A study of the β-- decay of a mass--separated source of 231Fr has produced the first level scheme of 231Ra (2001Fr05). The only published data (1994Br36,1996Le01) on the electron--capture decay of 231U have provided much information on the level structure of 231Pa. Studies on 232Th(p,2nγ) and Coulomb Excitation of 231Pa (1996Le01,1999Wu05), which have complemented the existing spectroscopic data from these reactions, have suggested the possibility of weak octupole correlations in 231Pa. A new isotope of plutonium, 231Pu (1999La14), has been included in this evaluation.
Nuclear data sheets for A = 215,219,223,227
1992, Nuclear Data SheetsThis publication presents evaluated spectroscopic data and corresponding level schemes from radioactive decay and nuclear reaction studies for all nuclei with mass numbers A=215, 219, 223, and 227.
Nuclei with mass number A=215 have spherical shape, and their nuclear structure has been interpreted in terms of the shell model. Nuclei with mass number A=219 belong to a transitional region, with spherical, quadrupole, and possibly, octupole deformations, and those with mass numbers A=223 and 227, to newly studied regions of deformations (pure quadrupole coexisting with possible octupole). Because deformations are small in these regions, nuclear states are no longer fully characterized by single Nilsson orbitals. This terminology, however, is used throughout this evaluation to label states rather than to accurately describe their nature.
Highlights of this publication include the emission of 14C by 223Ra, discovered by Rose and Jones (84Ro30), and its fine structure, measured by Brillard et al. (89Br34). This constitutes a new mode of decay and provides additional arguments for configuration assignments. They further include the first set of nuclear levels in 215Fr, 215Ra, and 215Ac, determined from in—beam γ-ray spectroscopic measurements.
Two major publications have been extensively used in this evaluation: the theoretical paper “Reflection—asymmetric Rotor Model of Odd—A ≈219–229 Nuclei” by Leander and Chen (88Le13), which presents a calculation of single—particle state properties by the coupling of shell—model states to a reflection—asymmetric rotor core; and the review paper “Intrinsic States of Deformed Odd—A Nuclei in the Mass Regions (151≤A≤193) and (A≥221)” by Jain et al. (90Ja11), which gives the systematics and assignments of single—particle states in such mass regions.
These evaluations for A=215, 219, 223, and 227 supersede the earlier ones by C. Maples: 77Ma29, Nuclear Data Sheets 22, 207 (1977); 77Ma30, Nuclear Data Sheets 22, 223 (1977); 77Ma31, Nuclear Data Sheets 22, 243 (1977); and 77Ma32, Nuclear Data Sheets 22, 275 (1977).
Nuclear data sheets for A = 215
1977, Nuclear Data SheetsAvailable information on decay characteristics and level structure for all nuclei with A = 215 has been examined. A summary and evaluation of exprimental data, including adopted values and comparison with theory are presented. The individual level schemes are discussed, and comments pertaining to adopted spin and parity assignments and to gamma-ray multipolarities are given. Any apparent discrepancies and inconsistencies are pointed out.
Much of the level information in the A = 215 mass chain is obtained from the α=decay of the A = 219 parent nuclei While a summary of these results is reflected in both the level schemes and in discussions under “Level Properties” and “Gamma-Ray Properties”, the actual data are presented under the respective A = 219 parent.
Decay energies and separation energies have been taken systematically from the 1977 Mass Adjustment (76WaBo, 77Wa08). Detailed ocmparison has been made between the adopted α-energies and the input values to the Mass Adjustment.
Nuclear data sheets for A = 219
1977, Nuclear Data SheetsAvailable information on decay characteristics and level structure for all nuclei with A = 219 has been examined. A summary and evaluation of experimental data, including adopted values and comparison with theory are presented. The individual level schemes are discussed, and comments pertaining to adopted spin and parity assignments and to gamma-ray multipolarities are given. Any apparent discrepancies and inconsistencies are pointed out.
Much of the level information in the A = 219 mass chain is obtained from the α-decay of the A = 223 parent nuclei. While a summary of these results is reflected in both the level schemes and in discussions under “Level Properties” and “Gamma-Ray Properties”, the actual data are presented under the respective A = 223 parent.
Decay energies and separation energies have been taken systematically from the 1977 Mass Adjustment (76WaBo, 77Wa08). Detailed comparison has been made between the adopted α-energies and the input values to the Mass Adjustment.
Electromagnetic transition rates in <sup>215</sup>Po
1974, Nuclear Physics, Section AThe half-lives of the excited levels at 272 and 402 keV in 215Po have been measured by the delayed coincidence and α-recoil Doppler shift attenuation methods to be 195(15) ps and 66(5) ps, respectively. Reduced electromagnetic transition probabilities are deduced. The results are interpreted in terms of the core excitation model.