New isotopes of emanation and francium: 223Em, 224Em and 224Fr☆
Abstract
An examination of the products of the interaction of thorium with 230 MeV protons has revealed evidence for the existence of the neutron-excess isotopes: 223Em, 224Em and 224Fr.
The existence of these three new isotopes was confirmed by identification of their decay products: 223Ra and 224Ra.
References (3)
- B.M. Foreman et al.
J. Inorg. Nucl. Chem.
(1958)
Cited by (7)
Nuclear Data Sheets for A = 224
2015, Nuclear Data SheetsThe experimental nuclear spectroscopic data for ten experimentally known nuclides of mass number 224 (Bi, Po, At, Rn, Fr, Ra, Ac, Th, Pa, U) have been evaluated and presented together with the Adopted properties for levels and γ rays. For 224Bi, 224Po, 224At, 224Rn, 224Fr, 224Pa and 224U nuclei, only the ground–state information is known. Half–lives of ground states of 224Bi and 224Po have not yet been measured. The decay of 224Rn to 224Fr has been studied, but no decay scheme has been proposed. The decay of 224Ac to 224Ra is reported only in an abstract style conference proceedings. For a definite Jπ assignment for ground state of 224Ac, a detailed study of this decay may be helpful. In the decay of 228Pa to 224Ac, authors of 1994Ah03 state that the lowest state observed in their work may not be the ground state. Thus an extensive study of 228Pa α decay, and studies involving nuclear reactions are warranted since the level scheme of 224Ac presented in this evaluation is considered as incomplete due to the lack of confirmed information about multipolarities, mixing ratios and other spectroscopic details. Three new nuclides 224Bi, 224Po, and 224At are added in this revision, together with new in–beam γ–ray and Coulomb excitation data for 224Ra. Although, not much new experimental data have appeared since the previous evaluation (1997Ar05), extensive modifications have been made in almost all the datasets. This work supersedes the information presented in the previous NDS evaluations of A = 224: 1997Ar05, 1986Ma45 and 1976El05.
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 = 224
1997, Nuclear Data SheetsAbstract:Detailed level schemes, decay schemes, and the experimental data on which they are based are presented for all nuclei with mass number A=224. The experimental data are evaluated, inconsistencies and discrepancies are noted, and adopted values for level and γ-ray energies, γ intensities, as well as for other nuclear properties are given.
Cutoff Date:All data received by October 1996 have been included.
General Policies and Organization of Material:See the January issue of Nuclear Data Sheets.
Acknowledgments:The advice and assistance of the members of the Nuclear Data Project (Oak Ridge National Laboratory) and National Nuclear Data Center (Brookhaven National Laboratory) are gratefully acknowledged. The evaluator is also indebted to the editors and reviewers of the Nuclear Data Sheets for their critical review of the manuscript.
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 = 216, 220, 224, and 228
1986, Nuclear Data SheetsDetailed level schemes, decay schemes, and the experimental data on which they are based are presented for all nuclei with mass numbers A=216, 220, 224, and 228. The experimental data are evaluated; inconsistencies and discrepancies are noted; and adopted values for level and γ-ray energies, γ intensities, as well as for other nuclear properties are given.
Nuclear data sheets for A = 223
1977, Nuclear Data SheetsAvailable information on decay characteristics and level structure for all nuclei with A = 223 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 coments 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 = 223 mass chain is obtained from the α-decay and the A = 227 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 = 227 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.
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Research work carried out in Radiochemistry Laboratories at Liverpool University 1959–1960.