PARTICLE-GAMMA COINCIDENCE STUDIES OF ALPHA-INDUCED REACTIONS ON C$sup 12$ AND Ne$sup 2$$sup 0$
The 22-Mev alpha -particle beam of the Indiana University cyclotron was used to bombard targets of C/sup 12/ and Ne/sup 20/. Angularr distributions of elastic and inelastic particle groups were measured for both nuclei. Qualitative comparison of the results both with current nuclear interaction theory and with measurements at other bombarding energies are shown. Problems concerning the production of unnatural-parity states are discussed. A search was made for a weak gamma -transition between the 9.63-Mev (3/sup -/) and the 4.43-Mev (2/sup +/ ) excited states of C/sup 12/ using the reaction ques. Weak evidence for this transition is indicated by the data, and the theoretical implications of such a transition are discussed. Angular correlations were measured between the 4.43- Mev gamma -ray and the inelastic alpha group from the 4.43Mev (2/sup +/) level of C/sup 12/. The results show agreement (at small laboratory angles) with the predictions of inelastic diffraction scattering in the adiabatic approximation. Coincidence spectra of the reaction C/sup 12/ ( alpha ,p gamma )N/sup 15/ (Q = - 4.96 Mev) reveal the existence of a 2.3-Mev gamma transition between the 7.57- Mev and the 5.28-Mev excited states of N/sup 15/. This transition is consistent with the shell-model predictions for the spins and parities of the two states. Coincidence spectra of the reaction Ne/sup 20/( alpha alpha ' gamma )Ne/sup 20/ provide evidence for the existence of two new levels in Ne/sup 20/, and several gamma transitions. A level at 7.93 Mev is thought to have spin and parity 3/sup +/ and to decay by cascade through the 4.97-Mev (2/sup -/) level. Another level at 5.88 Mev is tentatively assigned 3/sup +/ and is found to decay strongly by cascade through the 4.25-Mev (4/sup +/) level and weakly by cascade through the 1.63-Mev (2/sup +/) level. Some verification of the recent report of a new 7.26- Mev gamma-emitting level is given. Also, the existence of the recently discovered 7.02 state is verified by the coincidence spectra. Possible interpretation of the Ne/sup 20/ levels as rotational bands is discussed, and the difficulties of fitting the levels into rotational bands are presented. (Dissertation Abst., Vol. 23, No. 7).
- Research Organization:
- Originating Research Org. not identified
- NSA Number:
- NSA-17-017290
- OSTI ID:
- 4720993
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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Related Subjects
ALPHA BEAMS
ANGULAR DISTRIBUTION
CARBON 12
COINCIDENCE METHODS
CYCLOTRONS
DECAY
DIFFRACTION
ENERGY
ENERGY LEVELS
ENERGY RANGE
GAMMA RADIATION
MEASURED VALUES
NEON 20
NITROGEN 15
NUCLEAR MODELS
NUCLEAR REACTIONS
ORBITS
PARITY
PHYSICS
PROTONS
Q-VALUE
ROTATION
SCATTERING
SPECTRA
SPIN
TARGETS