Thermal-neutron scattering lengths and capture by even calcium isotopes

Journal Article · Sat Apr 01 04:00:00 EST 1989 · Phys. Rev. C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.39.1297· OSTI ID:6312185

Raman, S; Kahane, S; Moon, R M; Fernandez-Baca, J A; Zarestky, J L; Lynn, J E; Richardson, Jr, J W

Neutron-diffraction patterns have been measured for isotopically enriched powder samples of calcite using both steady-state and pulsed-neutron techniques. Greatly enhanced precision over previous work has been achieved for /sup 40/Ca and /sup 44/Ca, while the results for /sup 42/Ca, /sup 43/Ca, and /sup 48/Ca represent new data. The coherent scattering lengths deduced from these measurements have been employed in a more definitive analysis of primary electric-dipole gamma rays from thermal-neutron capture. In three cases (/sup 40/Ca, /sup 42/Ca, and /sup 48/Ca) the estimates from a spherical optical-model formulation of the direct-capture mechanism are in agreement with the experimental cross sections. In /sup 44/Ca the theory overestimates the measured cross sections on average by about 60%; this divergence can be explained by considering the modifications to the theory due to collective vibrations of the /sup 44/Ca core.

• Research Organization: Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
• OSTI ID: 6312185
• Journal Information: Phys. Rev. C; (United States), Journal Name: Phys. Rev. C; (United States) Vol. 39:4; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

651520 -- Nuclear Properties & Reactions
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Experimental
653001* -- Nuclear Theory-- Nuclear Structure
Moments
Spin
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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALKALINE EARTH METAL COMPOUNDS
BARYON REACTIONS
BARYONS
CALCITE
CALCIUM 40 TARGET
CALCIUM 42 TARGET
CALCIUM 44 TARGET
CALCIUM 48 TARGET
CALCIUM CARBONATES
CALCIUM COMPOUNDS
CAPTURE
CARBON COMPOUNDS
CARBONATE MINERALS
CARBONATES
COHERENT SCATTERING
CROSS SECTIONS
DIFFRACTION
DIMENSIONS
DIPOLE MOMENTS
DIRECT REACTIONS
ELECTRIC DIPOLE MOMENTS
ELECTRIC MOMENTS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
FERMIONS
GAMMA RADIATION
HADRON REACTIONS
HADRONS
IONIZING RADIATIONS
LENGTH
MINERALS
NEUTRON DIFFRACTION
NEUTRON REACTIONS
NEUTRONS
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUCLEONS
OPTICAL MODELS
OXYGEN COMPOUNDS
PULSED NEUTRON TECHNIQUES
RADIATIONS
SCATTERING
SCATTERING LENGTHS
TARGETS
THERMAL NEUTRONS
TIME-OF-FLIGHT METHOD