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Title: Excitation of a spontaneously fissile isomer in positron annihilation in the K shell of an atom

Abstract

Theoretical estimates are presented for the cross sections for excitation of spontaneously fissile isomers of uranium in the nonradiative annihilation of a positron in the K shell of the atom. Calculations have been made for the series of multipoles E0, E1, E2, E3, E4, and also M1, M2, M3 in the positron energy range E/sub +/ from 1.5 to 2.5 MeV, which corresponds to the nuclear excitation interval E*=1.9--2.9 Mev, where it is assumed that the levels of the spontaneously fissile isomers are located. Various schemes of excitation of the isomers are considered, both in terms of the accepted hypothesis of shape isomerism of the nucleus and also in the possible hypothesis of a multiparticle nature of the structure of the isomeric state. Concrete calculations have been made for the isotopes /sup 236/U and /sup 238/U, for which in particular there exist sufficient experimental data for evaluation of the cross section for direct excitation to a spontaneously fissile isomeric state in terms of the model of shape isomerism, which in principle permits a check of this model. The theoretical values presented for the cross sections for nonradiative annihilation of positrons can be used also in estimates for the region ofmore » nuclei Z=90--96.« less

Authors:
;
Publication Date:
Research Org.:
I. V. Kurchatov Institute of Atomic Energy
OSTI Identifier:
5873481
Alternate Identifier(s):
OSTI ID: 5873481
Resource Type:
Journal Article
Journal Name:
Sov. J. Nucl. Phys. (Engl. Transl.); (United States)
Additional Journal Information:
Journal Volume: 29:2
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 74 ATOMIC AND MOLECULAR PHYSICS; FISSION ISOMERS; EXCITATION; POSITRON-ATOM COLLISIONS; ANNIHILATION; URANIUM 236; URANIUM 238; CROSS SECTIONS; ISOMERIC NUCLEI; K SHELL; MULTIPOLES; SPONTANEOUS FISSION; ACTINIDE ISOTOPES; ACTINIDE NUCLEI; ALPHA DECAY RADIOISOTOPES; ATOM COLLISIONS; BASIC INTERACTIONS; COLLISIONS; DECAY; ELECTROMAGNETIC INTERACTIONS; ELECTRONIC STRUCTURE; ENERGY-LEVEL TRANSITIONS; EVEN-EVEN NUCLEI; FISSION; HEAVY NUCLEI; INTERACTIONS; ISOTOPES; NUCLEAR REACTIONS; NUCLEI; POSITRON COLLISIONS; RADIOISOTOPES; URANIUM ISOTOPES; YEARS LIVING RADIOISOTOPES 653006* -- Nuclear Theory-- Spontaneous & Induced Fission; 640304 -- Atomic, Molecular & Chemical Physics-- Collision Phenomena; 652013 -- Nuclear Properties & Reactions, A=220 & above, Theoretical-- Energy Levels & Transitions-- (-1987)

Citation Formats

Grechukhin, D.P., and Soldatov, A.A. Excitation of a spontaneously fissile isomer in positron annihilation in the K shell of an atom. United States: N. p., 1979. Web.
Grechukhin, D.P., & Soldatov, A.A. Excitation of a spontaneously fissile isomer in positron annihilation in the K shell of an atom. United States.
Grechukhin, D.P., and Soldatov, A.A. Thu . "Excitation of a spontaneously fissile isomer in positron annihilation in the K shell of an atom". United States.
@article{osti_5873481,
title = {Excitation of a spontaneously fissile isomer in positron annihilation in the K shell of an atom},
author = {Grechukhin, D.P. and Soldatov, A.A.},
abstractNote = {Theoretical estimates are presented for the cross sections for excitation of spontaneously fissile isomers of uranium in the nonradiative annihilation of a positron in the K shell of the atom. Calculations have been made for the series of multipoles E0, E1, E2, E3, E4, and also M1, M2, M3 in the positron energy range E/sub +/ from 1.5 to 2.5 MeV, which corresponds to the nuclear excitation interval E*=1.9--2.9 Mev, where it is assumed that the levels of the spontaneously fissile isomers are located. Various schemes of excitation of the isomers are considered, both in terms of the accepted hypothesis of shape isomerism of the nucleus and also in the possible hypothesis of a multiparticle nature of the structure of the isomeric state. Concrete calculations have been made for the isotopes /sup 236/U and /sup 238/U, for which in particular there exist sufficient experimental data for evaluation of the cross section for direct excitation to a spontaneously fissile isomeric state in terms of the model of shape isomerism, which in principle permits a check of this model. The theoretical values presented for the cross sections for nonradiative annihilation of positrons can be used also in estimates for the region of nuclei Z=90--96.},
doi = {},
journal = {Sov. J. Nucl. Phys. (Engl. Transl.); (United States)},
number = ,
volume = 29:2,
place = {United States},
year = {1979},
month = {2}
}