Complex radioactivity

doi:10.1016/0375-9474(89)90653-2

Nuclear Physics A

Volume 502, 9 October 1989, Pages 41-58

https://doi.org/10.1016/0375-9474(89)90653-2 Get rights and content

Abstract

Twelve cases of radioactive decay involving emission of monoenergetic ¹⁴C, Ne, Mg or Si nuclei have been discovered. Partial half-lives range from 10¹¹ to 10²⁸s; branching ratios relative to alpha decay range from ~10⁻¹⁶ to ~10⁻⁹. A hindrance factor of ~40 in emission rate favors even-even over odd-A parents. Both cluster models and superasymmetric fission models fit the decay rates to within a factor 2 to 3.

References (55)

D.N. Poenaru
At. Data Nucl. Data Tables
(1986)
E. Hourani
Phys. Lett.
(1985)
Wang Shicheng
Nucl. Instr. Meth.
(1988)
R. Blendowske et al.
Phys. Rev. Lett.
(1988)
F. Barranco et al.
Phys. Rev. Lett.
(1988)
V.A. Rubchenya et al.
Iz. Akad. Nauk SSSR, Ser. Fiz.
(1986)
B. Buck et al.
Phys. Rev. C
(1975)
D.N. Poenaru
Institute for Theor. Physics (Univ. of Frankfurt) preprint 226
(1988)
M. Ivascu et al.
Nucl. Phys.
(1988)
A. Sandulescu et al.
Sov. J. Part. Nucl.
(1980)

D.N. Poenaru et al.

J. Phys. (Paris)

(1984)

D.N. Poenaru et al.

Rev. Roum. Phys.

(1984)

D.N. Poenaru et al.

J. Phys. G

(1984)

D.N. Poenaru et al.

Phys. Rev. C

(1985)

D.N. Poenaru

publ. NP-54-86, Inst. Central de Fizica

(1986)

W. Greiner et al.

D.V. Aleksandrov

JETP Lett.

(1984)

H.J. Rose et al.

Nature

(1984)

W. Shicheng

Phys. Rev. C Rapid Commun.

(1989)

P.B. Price et al.

Phys. Rev. Lett.

(1985)

S.W. Barwick

Phys. Rev. C

(1986)

S. Gales

Phys. Rev. Lett.

(1984)

W. Kutschera

Phys. Rev. C

(1985)

R.L. Fleischer et al.

Nuclear Tracks in Solids

(1975)

D. Hasegan et al.

Wang Shicheng

Phys. Rev. C Rapid Comm.

(1987)

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Three disintegration modes of the parent nucleus $^{222} Ra$ , namely the fission, the cluster emission and the alpha decay, are treated in a unified manner. The half-lives are calculated by taking into account the penetration probabilities through the potential barrier along disintegration trajectories in the deformation space appropriate to each kind of decay. These trajectories start from the same parent ground state configuration. The disintegration paths are obtained from the least action principle. The deformation energy is calculated within the macroscopic–microscopic procedure based on the Woods–Saxon two center shell model. The effective mass is determined microscopically with the cranking method and the Gaussian Overlap Approximation. The nuclear shape parametrization is characterized by the most important five degrees of freedom encountered in fission, corresponding to the elongation, the mass asymmetry, the necking and the two fragment deformations. Partial half-life results for alpha-decay and cluster emission processes treated as superasymmetric fission agree with the experimental data. The spontaneous fission half-life is predicted. Molecular states are evidenced for the superasymmetric fission process as a result of the large shell effects in the nascent fragments.
Alpha and exotic cluster decay with a new single particle basis
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A single particle basis consisting of two different harmonic oscillator representations is introduced with the aim of studying microscopically alpha and cluster decay processes. A correct description of the wave functions at large distances is obtained within a minimal single particle basis. Experimental data corresponding to a large number of alpha decay transitions from even-even nuclei are well reproduced. Applications to ¹⁴C decay from Ra isotopes are presented.
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1999, Radiation Measurements
The technique of Solid State Nuclear Track Detection (SSNTD) has matured since long as a viable method of charged particle detection. The usage of this method has been successfully extended to neutron detection and gamma dose measurements as well. The etch-track mechanism has been further exploited to generate a major application area of nuclear track filters. In spite of the remarkable diversity of SSNTD applications that have emerged over the years in different fields, its potential is by no means saturated. In this article, a brief review of SSNTD applications is presented with reference to contemporary interests in science and technology. For convenience, the coverage of topics is organized under broad categories of Nuclear Physics, Materials Research, Geology, Environmental Science and allied technologies. While identifying high interest areas, those with limited but innovative applications are also mentioned. In some cases, the important results are quoted for the purpose of illustrating the strength of track detection method. In general, the presentation is aimed at providing a broad perspective of current SSNTD uses instead of detailed description of individual applications. The coverage is selective rather than exhaustive and portrays authors' preferences. Some comments related to the adoption of this technique as a mainstream method of detection are also given.
Microscopic theory of cluster radioactivity
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Recent developments in the dynamical microscopic theories of cluster decay are reviewed with special emphasis on the nuclear structure aspects and physical interpretation of the models. What we call dynamical microscopic theories are those in which the decay width is derived from the nucleonic structures, of the participating nuclei, which are deduced through the solution of their equations of motion. After a brief review of the various expressions for the decay width, we turn to the nuclear-structure aspects of the problem. We thoroughly discuss the treatment of the Pauli effects in models involving macroscopic elements. We settle the long-standing controversy over the cluster-core norm operator that relates microscopic and macroscopic relative-motion wave functions in the transition amplitude. We conclude that the way the norm operator was originally introduced in the mid-1970s is in principle correct. The main part of the paper is a detailed review, in which the approaches considered are categorized according to the structure models used for the parent nucleus. The approaches discussed are the ordinary shell models, the cluster-like shell models and the Bardeen-Cooper-Schrieffer (BCS) approach. By discussing these diverse calculations, it is concluded that the most essential prerequisite for a realistic model of the mother nucleus is that it should correctly describe the cluster correlation in the surface region. This implies that the proton-neutron interaction is indispensable, and the moderate success of ordinary shell models is accounted for by their failure to include both proton-neutron interaction and large enough bases. For the special case of a doubly-closed-shell residual state, cluster-like models are able to cope with this problem, because their bases are more economical, and, for these cases, they provide a fully satisfactory decay theory. The BCS approach, on the other hand, is widely applicable, and is the only one that has been applied to heavy-cluster decay with reasonable success. We point out, however, that the formation amplitude calculated in this model still contains approximations. We explain the success of the BCS theory by showing that, in spite of appearance, it does include proton-neutron interaction, in an effective manner. In discussing the results for the widths, we address the problem of the preformation probability of a cluster-core pair in the parent nucleus. One can be fairly confident that in the ground state of ²¹²Po the amount of core-α-clustering is as high as 20–30%, but, in respect of other cluster-decaying nuclei, the theory is not yet conclusive. We conclude that a satisfactory understanding of heavy-cluster radioactivity requires the application of both more sophisticated cluster models and improved BCS approaches.
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The results of the investigation of some properties of polyethyleneterephtalate, phosphate glass and mica for the study of cluster decay and spontaneous fission of heavy nuclei are given. The investigation results of ²³⁰U cluster decay and ²²⁶Ra spontaneous fission investigation are presented. The probability of ²³⁰U cluster decay in relation to α-decay is less than 7.5·10¹⁴. The partial half-life of ²²⁶Ra spontaneous fission is more than 6.6·10¹⁷ yrs. The fusion-fission cross sections for the ( $^{208} Pb +^{16} O →^{224} Th$ ) reaction, as the inverse reaction of cluster decay, in the subbarrier region of ion energy was measured. For the energies of 78, 75, 73 and 68 MeV ¹⁶O (lab.system) the cross-sections are 7.8; 3.7·10⁻², 8.5·10⁻⁴ and 6·10⁻⁶ mb, respectively.
Nuclear data sheets for A = 224
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Abstract: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.

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^☆: This work was supported in part by the U.S.Department of Energy. Much of the text was adapted from an article to appear in Annual Review of Nuclear and Particle Science, Vol. 39 (1989).

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Complex radioactivity☆

Abstract

At. Data Nucl. Data Tables

Phys. Lett.

Nucl. Instr. Meth.

Phys. Rev. Lett.

Phys. Rev. Lett.

Iz. Akad. Nauk SSSR, Ser. Fiz.

Phys. Rev. C

Nucl. Phys.

Sov. J. Part. Nucl.

J. Phys. (Paris)

Rev. Roum. Phys.

J. Phys. G

Phys. Rev. C

publ. NP-54-86, Inst. Central de Fizica

JETP Lett.

Nature

Phys. Rev. C Rapid Commun.

Phys. Rev. Lett.

Phys. Rev. C

Phys. Rev. Lett.

Phys. Rev. C

Nuclear Tracks in Solids

Phys. Rev. C Rapid Comm.