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

Journal Article · Thu Feb 01 04:00:00 EST 1979 · Sov. J. Nucl. Phys. (Engl. Transl.); (United States)

OSTI ID:5873481

Grechukhin, D P; Soldatov, A A

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.

• Research Organization: I. V. Kurchatov Institute of Atomic Energy
• OSTI ID: 5873481
• Journal Information: Sov. J. Nucl. Phys. (Engl. Transl.); (United States), Journal Name: Sov. J. Nucl. Phys. (Engl. Transl.); (United States) Vol. 29:2; ISSN SJNCA
• Country of Publication: United States
• Language: English

Related Subjects

640304 -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
652013 -- Nuclear Properties & Reactions
A=220 & above
Theoretical-- Energy Levels & Transitions-- (-1987)
653006* -- Nuclear Theory-- Spontaneous & Induced Fission
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
74 ATOMIC AND MOLECULAR PHYSICS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
ANNIHILATION
ATOM COLLISIONS
BASIC INTERACTIONS
COLLISIONS
CROSS SECTIONS
DECAY
ELECTROMAGNETIC INTERACTIONS
ELECTRONIC STRUCTURE
ENERGY-LEVEL TRANSITIONS
EVEN-EVEN NUCLEI
EXCITATION
FISSION
FISSION ISOMERS
HEAVY NUCLEI
INTERACTIONS
ISOMERIC NUCLEI
ISOTOPES
K SHELL
MULTIPOLES
NUCLEAR REACTIONS
NUCLEI
POSITRON COLLISIONS
POSITRON-ATOM COLLISIONS
RADIOISOTOPES
SPONTANEOUS FISSION
URANIUM 236
URANIUM 238
URANIUM ISOTOPES
YEARS LIVING RADIOISOTOPES