Thermal-neutron capture by magnesium isotopes

Journal Article · Wed Apr 01 04:00:00 EST 1992 · Physical Review, C (Nuclear Physics); (United States)

DOI:https://doi.org/10.1103/PhysRevC.45.1597· OSTI ID:7286527

Walkiewicz, T A; Raman, S ^[1]; Jurney, E T; Starner, J W; Lynn, J E ^[2]

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1. Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
2. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

We have studied the primary and secondary {gamma} rays (33 in {sup 25}Mg, 212 in {sup 26}Mg, and 35 in {sup 27}Mg) following thermal-neutron capture by the stable {sup 24}Mg, {sup 25}Mg, and {sup 26}Mg isotopes. Almost all of these {gamma} rays have been incorporated into the corresponding level schemes consisting of 9 excited levels in {sup 25}Mg, 55 in {sup 26}Mg, and 10 in {sup 27}Mg. In each case, the observed {gamma} rays account for nearly 100% of all captures. The measured neutron separation energies for {sup 25}Mg, {sup 26}Mg, and {sup 27}Mg are, respectively, 7330.65{plus minus}0.05, 11 093.18{plus minus}0.05, and 6443.40{plus minus}0.05 keV. The measured thermal-neutron capture cross sections for {sup 24}Mg, {sup 25}Mg, and {sup 26}Mg are, respectively, 54.1{plus minus}1.3, 200{plus minus}3, and 39.0{plus minus}0.8 mb. In all three cases, primary electric-dipole ({ital E}1) transitions account for the bulk of the total capture cross section. We have calculated these {ital E}1 partial cross sections using direct-capture theory. We have also speculated on the mechanism responsible for the magnetic-dipole ({ital M}1) transitions which are quite strong in {sup 26}Mg.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 7286527
• Journal Information: Physical Review, C (Nuclear Physics); (United States), Journal Name: Physical Review, C (Nuclear Physics); (United States) Vol. 45:4; ISSN 0556-2813; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

663430* -- Nucleon-Induced Reactions & Scattering-- (1992-)
663530 -- Nuclear Mass Ranges-- A=20-38-- (1992-)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTIVATION ANALYSIS
BARYON REACTIONS
BARYONS
CAPTURE
CHEMICAL ANALYSIS
E1-TRANSITIONS
ELEMENTARY PARTICLES
ENERGY-LEVEL TRANSITIONS
FERMIONS
GAMMA SPECTRA
HADRON REACTIONS
HADRONS
M1-TRANSITIONS
MAGNESIUM 25 TARGET
MAGNESIUM 26 TARGET
MAGNESIUM 27 TARGET
MULTIPOLE TRANSITIONS
NEUTRON ACTIVATION ANALYSIS
NEUTRON REACTIONS
NEUTRONS
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUCLEONS
SPECTRA
TARGETS
THERMAL NEUTRONS