FORMATION OF THE NUCLEAR ISOMERS OF SCANDIUM-44 AND COBALT-58 BY THE (/cap alpha/,N) REACTION
Journal Article
·
· Dissertation Abstr.
OSTI ID:4823304
Isomeric ratios, sigma /sub m/ sigma /sub g/, for the formation of Sc/ sup 44/ and Co/sup 58/ isomers in the ( alpha ,n) reactions were measured as a function of alpha-particle energy. The isomeric ratio of Sc/sup 44/ is 0.3 at 6 Mev, increases to 2.0 at 26 Mev, and then decreases to 0.9 at 40 Mev. Similar behavior was observed in the study of the Co/sup 58/ isomeric pair: 1.1 at 12 Mev, 3.4 at 20 Mev, and 1.9 at 29.5 Mev. Total cross sections for the isomeric pairs were also measured. The excitation function for Sc/sup 44/ showed an appreciable tail in the high-energy region. Based on the energy dependence of the isomeric ratio and the total cross section, it was concluded that the isomeric pairs are formed by a compound-nucleus mechanism at an alpha-particle energy below 20 Mev and partly by a direct-interaction mechanism at higher energies. This conclusion was confirmed by measuring the recoil ranges of Sc/sup 44/ and Co/sup 58/. As the alpha-particle energy was increased, the average ranges of the Sc/sup 44/ isomeric pair became less than that of Sc/sup 43/ which was taken to be formed by a compound-nucleus mechanism. The decrease in range was greater for the ground-state isomer. Similar behavior was observed when the average ranges of the Co/sup 58/isomeric pair were compared with that of Co/sup 57/. Calculations were made for the isomeric ratios predicted by a compoundnucleus mechanism and by a direct-interaction model. In the compound- nucleus reaction, the isomeric ratio is mainly determined by the energy of the alpha particle and the spin dependence of the level density in the residual nucleus. For a direct interaction, the spin dependence of the level density in the final product appears to be a predominant factor.
- Research Organization:
- Clark Univ., Worcester, Mass.
- NSA Number:
- NSA-16-023030
- OSTI ID:
- 4823304
- Journal Information:
- Dissertation Abstr., Journal Name: Dissertation Abstr. Vol. Vol: 22
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
Similar Records
YIELD RATIOS FOR THE ISOMERIC PAIR Sc$sup 44$m$sup 44$ FORMED IN (cap alpha, cap alpha n) AND (cap alpha,N) REACTIONS
INDEPENDENT YIELDS OF ISOMERIC PAIRS IN NUCLEAR REACTIONS (thesis)
RATIO OF CROSS SECTIONS FOR FORMATION OF THE Sc$sup 44$ AND Sc$sup 44$m PAIR IN HEAVY ION REACTIONS
Journal Article
·
Sat Jul 15 00:00:00 EDT 1961
· Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D
·
OSTI ID:4839777
INDEPENDENT YIELDS OF ISOMERIC PAIRS IN NUCLEAR REACTIONS (thesis)
Technical Report
·
Tue Mar 31 23:00:00 EST 1959
·
OSTI ID:4243268
RATIO OF CROSS SECTIONS FOR FORMATION OF THE Sc$sup 44$ AND Sc$sup 44$m PAIR IN HEAVY ION REACTIONS
Journal Article
·
Tue Oct 01 00:00:00 EDT 1963
· Zh. Eksperim. i Teor. Fiz.
·
OSTI ID:4117185